FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Bertucci, A Durante, M Gialanella, G Grossi, G Manti, L Pugliese, M Scampoli, P Mancusi, D Sihver, L Rusek, A AF Bertucci, A. Durante, M. Gialanella, G. Grossi, G. Manti, L. Pugliese, M. Scampoli, P. Mancusi, D. Sihver, L. Rusek, A. TI Shielding of relativistic protons SO RADIATION AND ENVIRONMENTAL BIOPHYSICS LA English DT Article; Proceedings Paper CT 4th International Workshop on Space Radiation Research/17th Annual NASA Space Radiation Health Investigators Meeting CY JUN 05-09, 2006 CL St Petersburg, RUSSIA ID ENERGY IRON IONS; HUMAN-LYMPHOCYTES; ABERRATIONS; RISK AB Protons are the most abundant element in the galactic cosmic radiation, and the energy spectrum peaks around 1 GeV. Shielding of relativistic protons is therefore a key problem in the radiation protection strategy of crewmembers involved in long-term missions in deep space. Hydrogen ions were accelerated up to 1 GeV at the NASA Space Radiation Laboratory, Brookhaven National Laboratory, New York. The proton beam was also shielded with thick ( about 20 g/cm(2)) blocks of lucite (PMMA) or aluminium ( Al). We found that the dose rate was increased 40-60% by the shielding and decreased as a function of the distance along the axis. Simulations using the General Purpose Particle and Heavy-Ion Transport code System (PHITS) show that the dose increase is mostly caused by secondary protons emitted by the target. The modified radiation Weld after the shield has been characterized for its biological eVectiveness by measuring chromosomal aberrations in human peripheral blood lymphocytes exposed just behind the shield block, or to the direct beam, in the dose range 0.53 Gy. Notwithstanding the increased dose per incident proton, the fraction of aberrant cells at the same dose in the sample position was not significantly modified by the shield. The PHITS code simulations show that, albeit secondary protons are slower than incident nuclei, the LET spectrum is still contained in the low-LET range (< 10 keV/mu m), which explains the approximately unitary value measured for the relative biological effectiveness. C1 Univ Naples Federico II, Dept Phys, I-80126 Naples, Italy. Univ Naples Federico II, Dept Biol, I-80126 Naples, Italy. Chalmers, S-41296 Gothenburg, Sweden. NASA, Space Radiat Lab, Brookhaven Natl Lab, Upton, NY 11973 USA. RP Durante, M (reprint author), Univ Naples Federico II, Dept Phys, Monte S Angelo,Via Cintia, I-80126 Naples, Italy. EM durante@na.infn.it RI Durante, Marco/K-1315-2014; OI Mancusi, Davide/0000-0002-2518-8228; Durante, Marco/0000-0002-4615-553X NR 11 TC 9 Z9 9 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0301-634X J9 RADIAT ENVIRON BIOPH JI Radiat. Environ. Biophys. PD JUN PY 2007 VL 46 IS 2 BP 107 EP 111 DI 10.1007/s00411-006-0088-6 PG 5 WC Biology; Biophysics; Environmental Sciences; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Environmental Sciences & Ecology; Radiology, Nuclear Medicine & Medical Imaging GA 166EF UT WOS:000246360000005 PM 17256178 ER PT J AU Hada, M Meador, JA Cucinotta, FA Gonda, SR Wu, H AF Hada, M. Meador, J. A. Cucinotta, F. A. Gonda, S. R. Wu, H. TI Chromosome aberrations induced by dual exposure of protons and iron ions SO RADIATION AND ENVIRONMENTAL BIOPHYSICS LA English DT Article; Proceedings Paper CT 4th International Workshop on Space Radiation Research/17th Annual NASA Space Radiation Health Investigators Meeting CY JUN 05-09, 2006 CL St Petersburg, RUSSIA ID ANCHORAGE-INDEPENDENT GROWTH; MAMMARY EPITHELIAL-CELLS; HUMAN-LYMPHOCYTES; INDUCTION; RADIATION; PARTICLES; RAYS AB During space travel, astronauts will be exposed to protons and heavy charged particles. Since the proton flux is high compared to HZE particles, on average, it is assumed that a cell will be hit by a proton before it is hit by an HZE ion. Although the effects of individual ion species on human cells have been investigated extensively, little is known about the effects of exposure to mixed beam irradiation. To address this, we exposed human epithelial cells to protons followed by HZE particles and analyzed chromosomal damage using the multicolor banding in situ hybridization (mBAND) procedure. With this technique, individually painted chromosomal bands on one chromosome allowed the identification of intra-chromosomal aberrations (inversions and deletions within a single painted chromosome) as well as inter-chromosomal aberrations (translocation to unpainted chromosomes). Our results indicated that chromosome aberration frequencies from exposures to protons followed by Fe ions did not simply decrease as the interval between the two exposures increased, but peak when the interval was 30 min. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Space Res Assoc, Houston, TX USA. RP Hada, M (reprint author), NASA, Lyndon B Johnson Space Ctr, 2101 NASA Pkwy, Houston, TX 77058 USA. EM megumi.hada1@jsc.nasa.gov NR 15 TC 10 Z9 12 U1 1 U2 3 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0301-634X J9 RADIAT ENVIRON BIOPH JI Radiat. Environ. Biophys. PD JUN PY 2007 VL 46 IS 2 BP 125 EP 129 DI 10.1007/s00411-006-0083-y PG 5 WC Biology; Biophysics; Environmental Sciences; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Environmental Sciences & Ecology; Radiology, Nuclear Medicine & Medical Imaging GA 166EF UT WOS:000246360000008 PM 17237947 ER PT J AU Ponomarev, AL Belli, M Hahnfeldt, PJ Hlatky, L Sachs, RK Cucinotta, FA AF Ponomarev, Artem L. Belli, Mauro Hahnfeldt, Philip J. Hlatky, Lynn Sachs, Rainer K. Cucinotta, Francis A. TI Subtraction of background damage in PFGE experiments on DNA fragment-size distributions SO RADIATION AND ENVIRONMENTAL BIOPHYSICS LA English DT Article; Proceedings Paper CT 4th International Workshop on Space Radiation Research/17th Annual NASA Space Radiation Health Investigators Meeting CY JUN 05-09, 2006 CL St Petersburg, RUSSIA ID FIELD GEL-ELECTROPHORESIS; DOUBLE-STRAND BREAKS; HIGH-LET RADIATION; LIGHT-IONS; MODEL AB The non-random distribution of DNA breakage in pulsed-field gel electrophoresis (PFGE) experiments poses a problem of proper subtraction of the background damage to obtain a fragment-size distribution due to radiation only. As been pointed out by various authors, a naive bin-to-bin subtraction of the background signal will not result in the right DNA mass distribution histogram, and may even result in negative values. Previous more systematic subtraction methods have been based mainly on random breakage, appropriate for low-LET radiation but problematic for high LET. Moreover, an investigation is needed whether the background breakage itself is random or non-random. Previously a new generalized formalism based on stochastic processes for the subtraction of the background damage in PFGE experiments for any LET and any background was proposed, and as now applied it to a set of PFGE data for Fe ions. We developed a Monte Carlo algorithm to compare the naive subtraction procedure in artificial data sets to the result produced by the new formalism. The simulated data corresponded to various cases, involving non-random (high-LET) or random radiation breakage and random or non-random background breakage. The formalism systematically gives better results than naive bin-by-bin subtraction in all these artificial data sets. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. USRA, Houston, TX 77058 USA. Ist Super Sanita, Technol & Hlth Dept, I-00161 Rome, Italy. Tufts Univ, Sch Med, St Elizabeths Med Ctr, Ctr Canc Syst Biol, Boston, MA 02135 USA. Univ Calif Berkeley, Dept Math & Phys, Berkeley, CA 94720 USA. RP Ponomarev, AL (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code SK,Build 37,Room 119, Houston, TX 77058 USA. EM aponomar@ems.jsc.nasa.gov NR 13 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0301-634X J9 RADIAT ENVIRON BIOPH JI Radiat. Environ. Biophys. PD JUN PY 2007 VL 46 IS 2 BP 155 EP 160 DI 10.1007/s00411-007-0098-z PG 6 WC Biology; Biophysics; Environmental Sciences; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Environmental Sciences & Ecology; Radiology, Nuclear Medicine & Medical Imaging GA 166EF UT WOS:000246360000012 PM 17406880 ER PT J AU Jamieson, BG Lynch, BA Harpold, DN Niemann, HB Shappirio, MD Mahaffy, PR AF Jamieson, B. G. Lynch, B. A. Harpold, D. N. Niemann, H. B. Shappirio, M. D. Mahaffy, P. R. TI Microfabricated silicon leak for sampling planetary atmospheres with a mass spectrometer SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID PIONEER VENUS; PROBE; ION; GERMANIUM; MISSION; HELIUM AB A microfabricated silicon mass spectrometer inlet leak has been designed, fabricated, and tested. This leak achieves a much lower conductance in a smaller volume than is possible with commonly available metal or glass capillary tubing. It will also be shown that it is possible to integrate significant additional functionality, such as inlet heaters and valves, into a silicon microleak with very little additional mass. The fabricated leak is compatible with high temperature (up to 500 degrees C) and high pressure (up to 100 bars) conditions, as would be encountered on a Venus atmospheric probe. These leaks behave in reasonable agreement with their theoretically calculated conductance, although this differs between devices and from the predicted value by as much as a factor of 2. This variation is believed to be the result of nonuniformity in the silicon etching process which is characterized in this work. Future versions of this device can compensate for characterized process variations in order to produce devices in closer agreement with designed conductance values. The integration of an inlet heater into the leak device has also been demonstrated in this work. (c) 2007 American Institute of Physics. C1 Sci & Biomed Microsyst, Severna Pk, MD 21146 USA. MEU Technol, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Jamieson, BG (reprint author), Sci & Biomed Microsyst, Severna Pk, MD 21146 USA. EM brianj@sbmicrosystems.com RI Mahaffy, Paul/E-4609-2012; Harpold, Dan/I-3345-2013 NR 21 TC 1 Z9 1 U1 1 U2 3 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 2007 VL 78 IS 6 AR 065109 DI 10.1063/1.2748360 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 184FJ UT WOS:000247626200043 PM 17614640 ER PT J AU Kosugi, T Matsuzaki, K Sakao, T Shimizu, T Sone, Y Tachikawa, S Hashimoto, T Minesugi, K Ohnishi, A Yamada, T Tsuneta, S Hara, H Ichimoto, K Suematsu, Y Shimojo, M Watanabe, T Shimada, S Davis, JM Hill, LD Owens, JK Title, AM Culhane, JL Harra, LK Doschek, GA Golub, L AF Kosugi, T. Matsuzaki, K. Sakao, T. Shimizu, T. Sone, Y. Tachikawa, S. Hashimoto, T. Minesugi, K. Ohnishi, A. Yamada, T. Tsuneta, S. Hara, H. Ichimoto, K. Suematsu, Y. Shimojo, M. Watanabe, T. Shimada, S. Davis, J. M. Hill, L. D. Owens, J. K. Title, A. M. Culhane, J. L. Harra, L. K. Doschek, G. A. Golub, L. TI The Hinode (Solar-B) mission: An overview SO SOLAR PHYSICS LA English DT Article ID MAGNETIC RECONNECTION; FLARE; CORONA; POINT; LOOPS AB The Hinode satellite (formerly Solar-B) of the Japan Aerospace Exploration Agency's Institute of Space and Astronautical Science (ISAS/JAXA) was successfully launched in September 2006. As the successor to the Yohkoh mission, it aims to understand how magnetic energy gets transferred from the photosphere to the upper atmosphere and results in explosive energy releases. Hinode is an observatory style mission, with all the instruments being designed and built to work together to address the science aims. There are three instruments onboard: the Solar Optical Telescope (SOT), the EUV Imaging Spectrometer (EIS), and the X-Ray Telescope (XRT). This paper provides an overview of the mission, detailing the satellite, the scientific payload, and operations. It will conclude with discussions on how the international science community can participate in the analysis of the mission data. C1 Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. Natl Astron Observ, Tokyo 1818588, Japan. Mitsubishi Electr Corp, Kamakura Works, Kanagawa 2478520, Japan. NASA, George C Marshall Space Flight Ctr, Space Sci Off, Huntsville, AL 35812 USA. Lockheed Martin Solar & Astrophys Lab, Palo Alto, CA 94304 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Shimizu, T (reprint author), Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. EM shimizu@solar.isas.jaxa.jp RI Shimojo, Masumi/J-2605-2016; OI Shimojo, Masumi/0000-0002-2350-3749; Harra, Louise/0000-0001-9457-6200; Golub, Leon/0000-0001-9638-3082 NR 23 TC 958 Z9 965 U1 7 U2 56 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JUN PY 2007 VL 243 IS 1 BP 3 EP 17 DI 10.1007/s11207-007-9014-6 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 215JB UT WOS:000249803500002 ER PT J AU Culhane, JL Harra, LK James, AM Al-Janabi, K Bradley, LJ Chaudry, RA Rees, K Tandy, JA Thomas, P Whillock, MCR Winter, B Doschek, GA Korendyke, CM Brown, CM Myers, S Mariska, J Seely, J Lang, J Kent, BJ Shaughnessy, BM Young, PR Simnett, GM Castelli, CM Mahmoud, S Mapson-Menard, H Probyn, BJ Thomas, RJ Davila, J Dere, K Windt, D Shea, J Hagood, R Moye, R Hara, H Watanabe, T Matsuzaki, K Kosugi, T Hansteen, V Wikstol, O AF Culhane, J. L. Harra, L. K. James, A. M. Al-Janabi, K. Bradley, L. J. Chaudry, R. A. Rees, K. Tandy, J. A. Thomas, P. Whillock, M. C. R. Winter, B. Doschek, G. A. Korendyke, C. M. Brown, C. M. Myers, S. Mariska, J. Seely, J. Lang, J. Kent, B. J. Shaughnessy, B. M. Young, P. R. Simnett, G. M. Castelli, C. M. Mahmoud, S. Mapson-Menard, H. Probyn, B. J. Thomas, R. J. Davila, J. Dere, K. Windt, D. Shea, J. Hagood, R. Moye, R. Hara, H. Watanabe, T. Matsuzaki, K. Kosugi, T. Hansteen, V. Wikstol, O. TI The EUV imaging spectrometer for Hinode SO SOLAR PHYSICS LA English DT Article ID CORONAL DIAGNOSTIC SPECTROMETER; SOLAR-B SATELLITE; MAGNETIC RECONNECTION; EMISSION-LINES; LABORATORY CALIBRATION; LOOP OSCILLATIONS; ATOMIC DATABASE; QUIET SUN; ULTRAVIOLET; SPECTRUM AB The EUV Imaging Spectrometer (EIS) on Hinode will observe solar corona and upper transition region emission lines in the wavelength ranges 170 - 210 angstrom and 250 - 290 angstrom. The line centroid positions and profile widths will allow plasma velocities and turbulent or non-thermal line broadenings to be measured. We will derive local plasma temperatures and densities from the line intensities. The spectra will allow accurate determination of differential emission measure and element abundances within a variety of corona and transition region structures. These powerful spectroscopic diagnostics will allow identification and characterization of magnetic reconnection and wave propagation processes in the upper solar atmosphere. We will also directly study the detailed evolution and heating of coronal loops. The EIS instrument incorporates a unique two element, normal incidence design. The optics are coated with optimized multilayer coatings. We have selected highly efficient, backside-illuminated, thinned CCDs. These design features result in an instrument that has significantly greater effective area than previous orbiting EUV spectrographs with typical active region 2 - 5 s exposure times in the brightest lines. EIS can scan a field of 6x8.5 arc min with spatial and velocity scales of 1 arc sec and 25 kms(-1) per pixel. The instrument design, its absolute calibration, and performance are described in detail in this paper. EIS will be used along with the Solar Optical Telescope (SOT) and the X-ray Telescope (XRT) for a wide range of studies of the solar atmosphere. C1 UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. Rutherford Appleton Lab, Space Sci & Technol Dept, Didcot OX11 0QX, Oxon, England. Univ Birmingham, Sch Phys & Space Res, Space Res Grp, Birmingham B15 2TT, W Midlands, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. George Mason Univ, Sch Computat Sci, Fairfax, VA 22030 USA. Columbia Univ, Dept Astron, Pupin Phys Labs, New York, NY 10027 USA. Perdix Corp, Wilton, NH 03086 USA. Swales Aerosp, Beltsville, MD 20705 USA. Artep Inc, Ellicott City, MD 21042 USA. Natl Astron Observ, Tokyo 181, Japan. Inst Space & Astronaut Sci, Kanagawa 229, Japan. Univ Oslo, Inst Theoret Astrophys, N-0315 Oslo, Norway. RP Culhane, JL (reprint author), UCL, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England. EM jlc@mssl.ucl.ac.uk OI Young, Peter/0000-0001-9034-2925; James, Adrian/0000-0002-0023-4363; Harra, Louise/0000-0001-9457-6200 NR 51 TC 537 Z9 542 U1 4 U2 23 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JUN PY 2007 VL 243 IS 1 BP 19 EP 61 DI 10.1007/s01007-007-0293-1 PG 43 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 215JB UT WOS:000249803500003 ER PT J AU Golub, L DeLuca, E Austin, G Bookbinder, J Caldwell, D Cheimets, P Cirtain, J Cosmo, M Reid, P Sette, A Weber, M Sakao, T Kano, R Shibasaki, K Hara, H Tsuneta, S Kumagai, K Tamura, T Shimojo, M McCracken, J Carpenter, J Haight, H Siler, R Wright, E Tucker, J Rutledge, H Barbera, M Peres, G Varisco, S AF Golub, L. DeLuca, E. Austin, G. Bookbinder, J. Caldwell, D. Cheimets, P. Cirtain, J. Cosmo, M. Reid, P. Sette, A. Weber, M. Sakao, T. Kano, R. Shibasaki, K. Hara, H. Tsuneta, S. Kumagai, K. Tamura, T. Shimojo, M. McCracken, J. Carpenter, J. Haight, H. Siler, R. Wright, E. Tucker, J. Rutledge, H. Barbera, M. Peres, G. Varisco, S. TI The X-ray telescope (XRT) for the Hinode mission SO SOLAR PHYSICS LA English DT Article ID I TELESCOPE; ABERRATION AB The X-ray Telescope (XRT) of the Hinode mission provides an unprecedented combination of spatial and temporal resolution in solar coronal studies. The high sensitivity and broad dynamic range of XRT, coupled with the spacecraft's onboard memory capacity and the planned downlink capability will permit a broad range of coronal studies over an extended period of time, for targets ranging from quiet Sun to X-flares. This paper discusses in detail the design, calibration, and measured performance of the XRT instrument up to the focal plane. The CCD camera and data handling are discussed separately in a companion paper. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. Natl Astron Observ, Tokyo 1818588, Japan. Natl Astron Observ, Nobeyama Solar Radio Observ, Minamisa Ku, Nagano 3841305, Japan. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Osservatorio Astron Palermo GS Vaiana, I-90134 Palermo, Italy. RP Golub, L (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM lgolub@cfa.harvard.edu RI DeLuca, Edward/L-7534-2013; Shimojo, Masumi/J-2605-2016; OI DeLuca, Edward/0000-0001-7416-2895; Shimojo, Masumi/0000-0002-2350-3749; Barbera, Marco/0000-0002-3188-7420; PERES, Giovanni/0000-0002-6033-8180; Varisco, Salvatore/0000-0002-6891-8390 NR 11 TC 393 Z9 397 U1 1 U2 7 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JUN PY 2007 VL 243 IS 1 BP 63 EP 86 DI 10.1007/s11207-007-0182-1 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 215JB UT WOS:000249803500004 ER PT J AU Cohen, CMS Mewaldt, RA Leske, RA Cummings, AC Stone, EC Wiedenbeck, ME von Rosenvinge, TT Mason, GM AF Cohen, C. M. S. Mewaldt, R. A. Leske, R. A. Cummings, A. C. Stone, E. C. Wiedenbeck, M. E. von Rosenvinge, T. T. Mason, G. M. TI Solar elemental composition based on studies of solar energetic particles SO SPACE SCIENCE REVIEWS LA English DT Review DE Sun : abundances; Sun : coronal mass ejections (CMEs); Sun : flares ID ISOTOPE SPECTROMETER; UPPER-ATMOSPHERE; CHARGE STATES; EVENTS; ABUNDANCES; SHOCK; FRACTIONATION; ACCELERATION; FLARES; WIND AB Solar abundances can be derived from the composition of the solar wind and solar energetic particles (SEPs) as well as obtained through spectroscopic means. Past comparisons have suggested that all three samples agree well, when rigidity-related fractionation effects on the SEPs were accounted for. It has been known that such effects vary from one event to the next and should be addressed on an event-by-event basis. This paper examines event variability more closely, particularly in terms of energy-dependent SEP abundances. This is now possible using detailed SEP measurements spanning several decades in energy from the Ultra Low Energy Isotope Spectrometer (ULEIS) and the Solar Isotope Spectrometer (SIS) on the ACE spacecraft. We present examples of the variability of the elemental composition with energy and suggest they can be understood in terms of diffusion from the acceleration region near the interplanetary shock. By means of a spectral scaling procedure, we obtain energy-independent abundance ratios for 14 large SEP events and compare them to reported solar wind and coronal abundances as well as to previous surveys of SEP events. C1 CALTECH, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. RP Cohen, CMS (reprint author), CALTECH, Pasadena, CA 91125 USA. EM cohen@srl.caltech.edu NR 34 TC 17 Z9 18 U1 0 U2 3 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD JUN PY 2007 VL 130 IS 1-4 BP 183 EP 194 DI 10.1007/s11214-007-9218-y PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 213GA UT WOS:000249653200019 ER PT J AU Leske, RA Mewaldt, RA Cohen, CMS Cummings, AC Stone, EC Wiedenbeck, ME von Rosenvinge, TT AF Leske, R. A. Mewaldt, R. A. Cohen, C. M. S. Cummings, A. C. Stone, E. C. Wiedenbeck, M. E. von Rosenvinge, T. T. TI Solar isotopic composition as determined using solar energetic particles SO SPACE SCIENCE REVIEWS LA English DT Review DE Sun : abundances; Sun : particle emission; Sun : coronal mass ejections (CMEs); Sun : flares ID IONIC CHARGE; HIGH-ENERGIES; EVENTS; ABUNDANCES; WIND; FRACTIONATION; SPECTROMETER; STATES; ACE AB Solar energetic particles (SEPs) provide a sample of the Sun from which solar composition may be determined. Using high-resolution measurements from the Solar Isotope Spectrometer (SIS) onboard NASA's Advanced Composition Explorer (ACE) spacecraft, we have studied the isotopic composition of SEPs at energies >= 20 MeV/nucleon in large SEP events. We present SEP isotope measurements of C, O, Ne, Mg, Si, S, Ar, Ca, Fe, and Ni made in 49 large events from late 1997 to the present. The isotopic composition is highly variable from one SEP event to another due to variations in seed particle composition or due to mass fractionation that occurs during the acceleration and/or transport of these particles. We show that various isotopic and elemental enhancements are correlated with each other, discuss the empirical corrections used to account for the compositional variability, and obtain estimated solar isotopic abundances. We compare the solar values and their uncertainties inferred from SEPs with solar wind and other solar system abundances and find generally good agreement. C1 CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leske, RA (reprint author), CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. EM ral@srl.caltech.edu NR 41 TC 13 Z9 13 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD JUN PY 2007 VL 130 IS 1-4 BP 195 EP 205 DI 10.1007/s11214-007-9185-3 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 213GA UT WOS:000249653200020 ER PT J AU Mewaldt, RA Cohen, CMS Mason, GM Cummings, AC Desai, MI Leske, RA Raines, J Stone, EC Wiedenbeck, ME von Rosenvinge, TT Zurbuchen, TH AF Mewaldt, R. A. Cohen, C. M. S. Mason, G. M. Cummings, A. C. Desai, M. I. Leske, R. A. Raines, J. Stone, E. C. Wiedenbeck, M. E. von Rosenvinge, T. T. Zurbuchen, T. H. TI On the differences in composition between solar energetic particles and solar wind SO SPACE SCIENCE REVIEWS LA English DT Review DE Sun : particle emission; Sun : solar wind; Sun : coronal mass ejections (CMEs); Sun : abundances; Sun : flares; acceleration of particles ID IONIC CHARGE STATES; ELEMENTAL ABUNDANCES; UPPER-ATMOSPHERE; SEED POPULATION; 1 AU; EVENTS; HEAVY; HE-3; FRACTIONATION; ACCELERATION AB Although the average composition of solar energetic particles (SEPs) and the bulk solar wind are similar in a number of ways, there are key differences which imply that solar wind is not the principal seed population for SEPs accelerated by coronal mass ejection (CME) driven shocks. This paper reviews these composition differences and considers the composition of other possible seed populations, including coronal material, impulsive flare material, and interplanetary CME material. C1 CALTECH, Pasadena, CA 91125 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. SW Res Inst, San Antonio, TX 78238 USA. Univ Michigan, Ann Arbor, MI 48109 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mewaldt, RA (reprint author), CALTECH, Pasadena, CA 91125 USA. EM rmewaldt@srl.caltech.edu NR 60 TC 40 Z9 40 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD JUN PY 2007 VL 130 IS 1-4 BP 207 EP 219 DI 10.1007/s11214-007-9187-1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 213GA UT WOS:000249653200021 ER PT J AU Cane, HV Richardson, IG von Rosenvinge, TT AF Cane, H. V. Richardson, I. G. von Rosenvinge, T. T. TI Fe/O ratios in interplanetary shock accelerated particles SO SPACE SCIENCE REVIEWS LA English DT Review DE acceleration of particles; shock waves; Sun : flares ID CORONAL MASS EJECTIONS; SEED POPULATION; 1 AU; EVENTS AB It is widely accepted that diffusive shock acceleration is an important process in the heliosphere, in particular in producing the energetic particles associated with interplanetary shocks driven by coronal mass ejections. In its simplest formulation shock acceleration is expected to accelerate ions with higher mass to charge ratios less efficiently than those with lower mass to charge. Thus it is anticipated that the Fe/O ratio in shock-accelerated ion populations will decrease with increasing energy above some energy. We examine the circumstances of five interplanetary shocks that have been reported to have associated populations in which Fe/O increases with increasing energy. In each event, the situation is complex, with particle contributions from other sources in addition to the shock. Furthermore, we show that the Fe/O ratio in shock-accelerated ions can decrease even when the shock is traveling through an Fe-rich ambient ion population. Thus, although shock acceleration of an Fe-rich suprathermal population has been proposed to explain large Fe-rich solar particle events, we find no support for this proposal in these observations. C1 NASA, Goddard Space Flight Ctr, Astroparticle Phys Lab, Greenbelt, MD 20771 USA. Univ Tasmania, Sch Math & Phys, Hobart, Tas, Australia. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Cane, HV (reprint author), NASA, Goddard Space Flight Ctr, Astroparticle Phys Lab, Greenbelt, MD 20771 USA. EM hilary.cane@utas.edu.au OI Richardson, Ian/0000-0002-3855-3634 NR 11 TC 11 Z9 11 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD JUN PY 2007 VL 130 IS 1-4 BP 301 EP 307 DI 10.1007/s11214-007-9201-7 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 213GA UT WOS:000249653200029 ER PT J AU Heber, VS Wiens, RC Reisenfeld, DB Allton, JH Baur, H Burnett, DS Olinger, CT Wiechert, U Wieler, R AF Heber, V. S. Wiens, R. C. Reisenfeld, D. B. Allton, J. H. Baur, H. Burnett, D. S. Olinger, C. T. Wiechert, U. Wieler, R. TI The genesis solar wind concentrator target: Mass fractionation characterised by neon isotopes SO SPACE SCIENCE REVIEWS LA English DT Review DE solar wind; noble gases; genesis oxygen isotopic analysis; UV laser ablation ID MISSION; MATTER; ION AB The concentrator on Genesis provided samples of increased fluences of solar wind ions for precise determination of the oxygen isotopic composition. The concentration process caused mass fractionation as a function of the radial target position. This fractionation was measured using Ne released by UV laser ablation and compared with modelled Ne data, obtained from ion-trajectory simulations. Measured data show that the concentrator performed as expected and indicate a radially symmetric concentration process. Measured concentration factors are up to similar to 30 at the target centre. The total range of isotopic fractionation along the target radius is 3.8%/amu, with monotonically decreasing Ne-20/Ne-22 towards the centre, which differs from model predictions. We discuss potential reasons and propose future attempts to overcome these disagreements. C1 ETH, Isotope Geol & Mineral Resources, CH-8092 Zurich, Switzerland. Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Univ Montana, Missoula, MT 59812 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. CALTECH, Pasadena, CA 91109 USA. Free Univ Berlin, AG Geochem, D-12249 Berlin, Germany. RP Heber, VS (reprint author), ETH, Isotope Geol & Mineral Resources, CH-8092 Zurich, Switzerland. EM heber@erdw.ethz.ch RI Wieler, Rainer/A-1355-2010; Reisenfeld, Daniel/F-7614-2015 OI Wieler, Rainer/0000-0001-5666-7494; NR 14 TC 7 Z9 7 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD JUN PY 2007 VL 130 IS 1-4 BP 309 EP 316 DI 10.1007/s11214-007-9179-1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 213GA UT WOS:000249653200030 ER PT J AU Leske, RA Mewaldt, RA Cohen, CMS Cummings, AC Stone, EC Wiedenbeck, ME von Rosenvinge, TT AF Leske, R. A. Mewaldt, R. A. Cohen, C. M. S. Cummings, A. C. Stone, E. C. Wiedenbeck, M. E. von Rosenvinge, T. T. TI An update on ultra-heavy elements in solar energetic particles above 10 MeV/Nucleon SO SPACE SCIENCE REVIEWS LA English DT Review DE Sun : abundances; Sun : particle emission; Sun : coronal mass ejections (CMEs); Sun : flares ID ABUNDANCES; EVENTS AB Measurements below several MeV/nucleon from Wind/LEMT and ACE/ULEIS show that elements heavier than Zn (Z=30) can be enhanced by factors of similar to 100 to 1000, depending on species, in He-3-rich solar energetic particle (SEP) events. Using the Solar Isotope Spectrometer (SIS) on ACE we find that even large SEP (LSEP) shock-accelerated events at energies from similar to 10 to > 100 MeV/nucleon are often very iron rich and might contain admixtures of flare seed material. Studies of ultra-heavy (UH) SEPs (with Z > 30) above 10 MeV/nucleon can be used to test models of acceleration and abundance enhancements in both LSEP and He-3-rich events. We find that the long-term average composition for elements from Z=30 to 40 is similar to standard solar system values, but there is considerable event-to-event variability. Although most of the UH fluence arrives during LSEP events, UH abundances are relatively more enhanced in He-3-rich events, with the (34 < Z < 40)/O ratio on average more than 50 times higher in He-3-rich events than in LSEP events. At energies > 10 MeV/nucleon, the most extreme event in terms of UH composition detected so far took place on 23 July 2004 and had a (34 < Z < 40)/O enhancement of similar to 250-300 times the standard solar value. C1 CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leske, RA (reprint author), CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. EM ral@srl.caltech.edu NR 13 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD JUN PY 2007 VL 130 IS 1-4 BP 335 EP 340 DI 10.1007/s11214-007-9191-5 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 213GA UT WOS:000249653200034 ER PT J AU Kruger, H Landgraf, M Altobelli, N Grun, E AF Krueger, Harald Landgraf, Markus Altobelli, Nicolas Gruen, Eberhard TI Interstellar dust in the solar system SO SPACE SCIENCE REVIEWS LA English DT Review DE dust; interstellar dust; heliosphere; interstellar matter ID MASS-DISTRIBUTION; ULYSSES; HELIOSPHERE; FLUX; GRAINS; DISCOVERY; STREAMS; GALILEO; ORBITS AB The Ulysses spacecraft has been orbiting the Sun on a highly inclined ellipse almost perpendicular to the ecliptic plane (inclination 79 degrees, perihelion distance 1.3 AU, aphelion distance 5.4 AU) since it encountered Jupiter in 1992. The in situ dust detector on board continuously measured interstellar dust grains with masses up to 10(-13) kg, penetrating deep into the solar system. The flow direction is close to the mean apex of the Sun's motion through the solar system and the grains act as tracers of the physical conditions in the local interstellar cloud (LIC). While Ulysses monitored the interstellar dust stream at high ecliptic latitudes between 3 and 5 AU, interstellar impactors were also measured with the in situ dust detectors on board Cassini, Galileo and Helios, covering a heliocentric distance range between 0.3 and 3 AU in the ecliptic plane. The interstellar dust stream in the inner solar system is altered by the solar radiation pressure force, gravitational focussing and interaction of charged grains with the time varying interplanetary magnetic field. We review the results from in situ interstellar dust measurements in the solar system and present Ulysses' latest interstellar dust data. These data indicate a 30 degrees shift in the impact direction of interstellar grains w.r.t. the interstellar helium flow direction, the reason of which is presently unknown. C1 Max Planck Inst Sonnensyst Forsch, D-37191 Katlenburg Lindau, Germany. Max Planck Inst Kernphys, D-69029 Heidelberg, Germany. European Space Agcy, ESOC, D-64293 Darmstadt, Germany. NASA, JPL, Pasadena, CA USA. Univ Hawaii, HIGP, Honolulu, HI 96822 USA. RP Kruger, H (reprint author), Max Planck Inst Sonnensyst Forsch, D-37191 Katlenburg Lindau, Germany. EM krueger@mps.mpg.de NR 23 TC 43 Z9 43 U1 0 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD JUN PY 2007 VL 130 IS 1-4 BP 401 EP 408 DI 10.1007/s11214-007-9181-7 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 213GA UT WOS:000249653200040 ER PT J AU Wiedenbeck, ME Binns, WR Cummings, AC Davis, AJ de Nolfo, GA Israel, MH Leske, RA Mewaldt, RA Stone, EC von Rosenvinge, TT AF Wiedenbeck, M. E. Binns, W. R. Cummings, A. C. Davis, A. J. de Nolfo, G. A. Israel, M. H. Leske, R. A. Mewaldt, R. A. Stone, E. C. von Rosenvinge, T. T. TI An overview of the origin of galactic cosmic rays as inferred from observations of heavy ion composition and spectra SO SPACE SCIENCE REVIEWS LA English DT Review DE ISM : cosmic rays; abundances; acceleration of particles; supernovae; general ID ADVANCED COMPOSITION EXPLORER; CHEMICAL EVOLUTION; ENERGY-SPECTRA; ELEMENTS; NUCLEOSYNTHESIS; SUPERBUBBLES; CONSTRAINTS; ABUNDANCES; SECONDARY; HYDROGEN AB The galactic cosmic rays arriving near Earth, which include both stable and long-lived nuclides from throughout the periodic table, consist of a mix of stellar nucleosynthesis products accelerated by shocks in the interstellar medium (ISM) and fragmentation products made by high-energy collisions during propagation through the ISM. Through the study of the composition and spectra of a variety of elements and isotopes in this diverse sample, models have been developed for the origin, acceleration, and transport of galactic cosmic rays. We present an overview of the current understanding of these topics emphasizing the insights that have been gained through investigations in the charge and energy ranges Z less than or similar to 30 and E/M less than or similar to 1 GeV/nuc, and particularly those using data obtained from the Cosmic Ray Isotope Spectrometer on NASA's Advanced Composition Explorer mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. CALTECH, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wiedenbeck, ME (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MC 169-327, Pasadena, CA 91109 USA. EM mark.e.wiedenbeck@jpl.nasa.gov RI de Nolfo, Georgia/E-1500-2012 NR 37 TC 13 Z9 13 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD JUN PY 2007 VL 130 IS 1-4 BP 415 EP 429 DI 10.1007/s11214-007-9198-y PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 213GA UT WOS:000249653200042 ER PT J AU Binns, WR Wiedenbeck, ME Arnould, M Cummings, AC de Nolfo, GA Goriely, S Israel, MH Leske, RA Mewaldt, RA Meynet, G Scott, LM Stone, EC von Rosenvinge, TT AF Binns, W. R. Wiedenbeck, M. E. Arnould, M. Cummings, A. C. de Nolfo, G. A. Goriely, S. Israel, M. H. Leske, R. A. Mewaldt, R. A. Meynet, G. Scott, L. M. Stone, E. C. von Rosenvinge, T. T. TI OB associations, wolf-rayet stars, and the origin of galactic cosmic rays SO SPACE SCIENCE REVIEWS LA English DT Review DE ISM : cosmic rays; Stars : Wolf-Rayet ID ISOTOPIC COMPOSITION; PARTICLE-ACCELERATION; MASSIVE STARS; SUPERBUBBLE ORIGIN; SUPERNOVA-REMNANTS; STELLAR EVOLUTION; ABUNDANCES; NUCLEOSYNTHESIS; CONSTRAINTS; NEON AB We have measured the isotopic abundances of neon and a number of other species in the galactic cosmic rays (GCRs) using the Cosmic Ray Isotope Spectrometer (CRIS) aboard the ACE spacecraft. Our data are compared to recent results from two-component (Wolf-Rayet material plus solar-like mixtures) Wolf-Rayet (WR) models. The three largest deviations of galactic cosmic ray isotope ratios from solar-system ratios predicted by these models,C-12/O-16, Ne-22/Ne-20, and Fe-58/Fe-56, are very close to those observed. All of the isotopic ratios that we have measured are consistent with a GCR source consisting of similar to 20% of WR material mixed with similar to 80% material with solar-system composition. Since WR stars are evolutionary products of OB stars, and most OB stars exist in OB associations that form superbubbles, the good agreement of our data with WR models suggests that OB associations within superbubbles are the likely source of at least a substantial fraction of GCRs. In previous work it has been shown that the primary Ni-59 (which decays only by electron-capture) in GCRs has decayed, indicating a time interval between nucleosynthesis and acceleration of > 10(5) y. It has been suggested that in the OB association environment, ejecta from supernovae might be accelerated by the high velocity WR winds on a time scale that is short compared to the half-life of Ni-59. Thus the Ni-59 might not have time to decay and this would cast doubt upon the OB association origin of cosmic rays. In this paper we suggest a scenario that should allow much of the Ni-59 to decay in the OB association environment and conclude that the hypothesis of the OB association origin of cosmic rays appears to be viable. C1 Washington Univ, St Louis, MO 63130 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Libre Bruxelles, Inst Astron & Astrophys, Brussels, Belgium. CALTECH, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Observ Geneva, CH-1290 Sauverny, Switzerland. RP Binns, WR (reprint author), Washington Univ, St Louis, MO 63130 USA. EM wrb@wuphys.wustl.edu RI de Nolfo, Georgia/E-1500-2012 NR 61 TC 18 Z9 18 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD JUN PY 2007 VL 130 IS 1-4 BP 439 EP 449 DI 10.1007/s11214-007-9195-1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 213GA UT WOS:000249653200044 ER PT J AU DellaCorte, C AF DellaCorte, Christopher TI Closing this chapter... SO TRIBOLOGY & LUBRICATION TECHNOLOGY LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP DellaCorte, C (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM cdellacorte@stle.org NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 1545-858X J9 TRIBOL LUBR TECHNOL JI Tribol. Lubr. Technol. PD JUN PY 2007 VL 63 IS 6 BP 6 EP 6 PG 1 WC Engineering, Mechanical SC Engineering GA 173VE UT WOS:000246899800002 ER PT J AU Saiz-Lopez, A Notario, A Albaladejo, J McFiggans, G AF Saiz-Lopez, Alfonso Notario, Alberto Albaladejo, Jose McFiggans, Gordon TI Seasonal variation of NOx loss processes coupled to the HNO3 formation in a daytime urban atmosphere: A model study SO WATER AIR AND SOIL POLLUTION LA English DT Article DE air pollution; atmospheric modelling; HNO3; traffic emissions; seasonal variation ID VOLATILE ORGANIC-COMPOUNDS; ACIDIFYING WET DEPOSITION; MASTER CHEMICAL MECHANISM; NITRIC-ACID MEASUREMENTS; GAS-PHASE REACTION; MCM V3 PART; TROPOSPHERIC DEGRADATION; CHEMISTRY; RADICALS; OZONE AB We studied the seasonal cycle of the coupling between atmospheric denoxification processes and in-situ daytime formation of gas phase HNO3 using a photochemical air pollution model. The model is constrained with urban atmospheric boundary layer observations of O-3, NO2 and NO made in Ciudad Real, central Spain. The highest daytime HNO3 mixing ratio of 0.3 ppbv was predicted to occur in summer, following a modelled OH concentration peak of similar to 1.4x10(6) molecules cm(-3) and subsequent reaction with NO2. During winter, calculated values of HNO3 are lower due to less incoming radiation and higher wet removal of atmospheric HNO3. The predicted mixing ratios are in good agreement with observations of atmospheric HNO3 at similar urban environments in central Spain. Additionally, a marked seasonal cycle is predicted with minimum HNO3 concentrations occurring in winter, indicative that traffic emissions and photochemistry dominate the in-situ formation of gas phase HNO3 at this location. This process has implications in the removal of NOx from the urban atmosphere. C1 CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. Univ Manchester, Sch Earth Atmospher & Envrionm Sci, Manchester M13 9PL, Lancs, England. Univ Castilla La Mancha, Fac Ciencias Quim, Ciudad Real 13071, Spain. Univ Castilla La Mancha, Inst Tecnol Quim & Medioambiental, Ciudad Real 13071, Spain. Univ Leeds, Sch Chem, Leeds LS2 9JT, W Yorkshire, England. RP Saiz-Lopez, A (reprint author), CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. EM alfonso.saiz-lopez@jpl.nasa.gov RI McFiggans, Gordon/B-8689-2011; Notario, Alberto/K-5975-2014; Saiz-Lopez, Alfonso/B-3759-2015; Albaladejo, Jose/N-3557-2014 OI McFiggans, Gordon/0000-0002-3423-7896; Notario, Alberto/0000-0003-0097-6647; Saiz-Lopez, Alfonso/0000-0002-0060-1581; Albaladejo, Jose/0000-0001-8776-6807 NR 40 TC 10 Z9 10 U1 0 U2 12 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0049-6979 J9 WATER AIR SOIL POLL JI Water Air Soil Pollut. PD JUN PY 2007 VL 182 IS 1-4 BP 197 EP 206 DI 10.1007/s11270-006-9332-6 PG 10 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA 166EJ UT WOS:000246360400018 ER PT J AU Hudson, TL Aharonson, O Schorghofer, N Farmer, CB Hecht, MH Bridges, NT AF Hudson, Troy L. Aharonson, Oded Schorghofer, Norbert Farmer, Crofton B. Hecht, Michael H. Bridges, Nathan T. TI Water vapor diffusion in Mars subsurface environments SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID POROUS-MEDIA; LIQUID WATER; GROUND ICE; PHYSICAL-PROPERTIES; GLOBAL DISTRIBUTION; GASEOUS DIFFUSION; MARTIAN REGOLITH; VIKING LANDERS; NEAR-SURFACE; STABILITY AB [1] The diffusion coefficient of water vapor in unconsolidated porous media is measured for various soil simulants at Mars-like pressures and subzero temperatures. An experimental chamber which simultaneously reproduces a low-pressure, low-temperature, and low-humidity environment is used to monitor water flux from an ice source through a porous diffusion barrier. Experiments are performed on four types of simulants: 40 - 70 mu m glass beads, sintered glass filter disks, 1 - 3 mu m dust ( both loose and packed), and JSC Mars - 1. A theoretical framework is presented that applies to environments that are not necessarily isothermal or isobaric. For most of our samples, we find diffusion coefficients in the range of 2.8 to 5.4 cm(2) s(-1) at 600 Pascal and 260 K. This range becomes 1.9 - 4.7 cm(2) s(-1) when extrapolated to a Mars-like temperature of 200 K. Our preferred value for JSC Mars - 1 at 600 Pa and 200 K is 3.7 +/- 0.5 cm(2) s(-1). The tortuosities of the glass beads is about 1.8. Packed dust displays a lower mean diffusion coefficient of 0.38 +/- 0.26 cm(2) s(-1), which can be attributed to transition to the Knudsen regime where molecular collisions with the pore walls dominate. Values for the diffusion coefficient and the variation of the diffusion coefficient with pressure are well matched by existing models. The survival of shallow subsurface ice on Mars and the providence of diffusion barriers are considered in light of these measurements. C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Hudson, TL (reprint author), CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. EM thudson@gps.caltech.edu RI Schorghofer, Norbert/A-1194-2007; Bridges, Nathan/D-6341-2016 NR 89 TC 48 Z9 48 U1 1 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 31 PY 2007 VL 112 IS E5 AR E05016 DI 10.1029/2006JE002815 PG 27 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 174NQ UT WOS:000246949400002 ER PT J AU McCleese, DJ Schofield, JT Taylor, FW Calcutt, SB Foote, MC Kass, DM Leovy, CB Paige, DA Read, PL Zurek, RW AF McCleese, D. J. Schofield, J. T. Taylor, F. W. Calcutt, S. B. Foote, M. C. Kass, D. M. Leovy, C. B. Paige, D. A. Read, P. L. Zurek, R. W. TI Mars Climate Sounder: An investigation of thermal and water vapor structure, dust and condensate distributions in the atmosphere, and energy balance of the polar regions SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID GENERAL-CIRCULATION MODEL; EMISSION SPECTROMETER; DATA ASSIMILATION; GLOBAL SURVEYOR; INTERANNUAL VARIABILITY; RECONNAISSANCE ORBITER; MAPPER OBSERVATIONS; MARTIAN ATMOSPHERE; RADIO OCCULTATION; SURFACE AB [1] Against a backdrop of intensive exploration of the Martian surface environment, intended to lead to human exploration, some aspects of the modern climate and the meteorology of Mars remain relatively unexplored. In particular, there is a need for detailed measurements of the vertical profiles of atmospheric temperature, water vapor, dust, and condensates to understand the intricately related processes upon which the surface conditions, and those encountered during descent by landers, depend. The most important of these missing data are accurate and extensive temperature measurements with high vertical resolution. The Mars Climate Sounder experiment on the 2005 Mars Reconnaissance Orbiter, described here, is the latest attempt to characterize the Martian atmosphere with the sort of coverage and precision achieved by terrestrial weather satellites. If successful, it is expected to lead to corresponding improvements in our understanding of meteorological phenomena and to enable improved general circulation models of the Martian atmosphere for climate studies on a range of timescales. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Oxford, Dept Phys, Oxford OX1 3PU, England. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. RP McCleese, DJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Daniel.J.McCleese@jpl.nasa.gov OI Calcutt, Simon/0000-0002-0102-3170 NR 55 TC 83 Z9 83 U1 1 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 31 PY 2007 VL 112 IS E5 AR E05S06 DI 10.1029/2006JE002790 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 174NQ UT WOS:000246949400001 ER PT J AU Mazarico, E Zuber, MT Lemoine, FG Smith, DE AF Mazarico, E. Zuber, M. T. Lemoine, F. G. Smith, D. E. TI Martian exospheric density using Mars Odyssey radio tracking data SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID GENERAL-CIRCULATION MODEL; SOLAR-CYCLE VARIATION; GLOBAL SURVEYOR; UPPER-ATMOSPHERE; ORBIT; THERMOSPHERES; ACCELEROMETER; EARTH; AEROBRAKING; IONOSPHERE AB We present measurements of the density of the Martian atmosphere at similar to 400 km altitude. Our analysis used radio tracking data to perform precise orbit determination on the Mars Odyssey spacecraft between March 2002 and November 2005. Recent improvements in a priori physical models make it possible to isolate the contribution of the atmospheric drag from the various forces acting on the spacecraft. For each spacecraft trajectory segment (arc) we adjusted an atmospheric drag coefficient (CD), which scales the a priori model density. From the drag coefficient we obtained a time series of the measured density. These measurements at the Mars Odyssey orbiting altitude are close to noise level, and the various tests we conducted show the robustness of the measurements. We obtained a better agreement with the atmospheric model used during the second Martian year, when solar activity is lower. Using various simple exponential atmosphere models, we estimated the scale height near the spacecraft periapsis and found values between 25 and 50 km, in the lower range of expected values, and used exospheric temperature estimates to assess the role of EUV heating of the upper atmosphere. We did not observe one-to-one correlation between solar activity and exospheric density, but we detected a solar rotation periodicity in our measurements. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Greenbelt, MD 20771 USA. RP Mazarico, E (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, 77 Massachusetts Ave, Cambridge, MA 02139 USA. EM mazarico@mit.edu RI Lemoine, Frank/D-1215-2013; Mazarico, Erwan/N-6034-2014 OI Mazarico, Erwan/0000-0003-3456-427X NR 49 TC 10 Z9 10 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 30 PY 2007 VL 112 IS E5 AR E05014 DI 10.1029/2006JE002734 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 174NN UT WOS:000246949100002 ER PT J AU Murchie, S Arvidson, R Bedini, P Beisser, K Bibring, JP Bishop, J Boldt, J Cavender, P Choo, T Clancy, RT Darlington, EH Marais, DD Espiritu, R Fort, D Green, R Guinness, E Hayes, J Hash, C Heffernan, K Hemmler, J Heyler, G Humm, D Hutcheson, J Izenberg, N Lee, R Lees, J Lohr, D Malaret, E Martin, T McGovern, JA McGuire, P Morris, R Mustard, J Pelkey, S Rhodes, E Robinson, M Roush, T Schaefer, E Seagrave, G Seelos, F Silverglate, P Slavney, S Smith, M Shyong, WJ Strohbehn, K Taylor, H Thompson, P Tossman, B Wirzburger, M Wolff, M AF Murchie, S. Arvidson, R. Bedini, P. Beisser, K. Bibring, J.-P. Bishop, J. Boldt, J. Cavender, P. Choo, T. Clancy, R. T. Darlington, E. H. Marais, D. Des Espiritu, R. Fort, D. Green, R. Guinness, E. Hayes, J. Hash, C. Heffernan, K. Hemmler, J. Heyler, G. Humm, D. Hutcheson, J. Izenberg, N. Lee, R. Lees, J. Lohr, D. Malaret, E. Martin, T. McGovern, J. A. McGuire, P. Morris, R. Mustard, J. Pelkey, S. Rhodes, E. Robinson, M. Roush, T. Schaefer, E. Seagrave, G. Seelos, F. Silverglate, P. Slavney, S. Smith, M. Shyong, W.-J. Strohbehn, K. Taylor, H. Thompson, P. Tossman, B. Wirzburger, M. Wolff, M. TI Compact reconnaissance Imaging Spectrometer for Mars (CRISM) on Mars Reconnaissance Orbiter (MRO) SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Review ID THERMAL EMISSION SPECTROMETER; ART. NO. 5115; OMEGA/MARS EXPRESS; MERIDIANI-PLANUM; MARTIAN SURFACE; ATMOSPHERIC DUST; GUSEV CRATER; WATER-VAPOR; MGS-TES; INTERANNUAL VARIABILITY AB The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is a hyperspectral imager on the Mars Reconnaissance Orbiter (MRO) spacecraft. CRISM consists of three subassemblies, a gimbaled Optical Sensor Unit (OSU), a Data Processing Unit (DPU), and the Gimbal Motor Electronics (GME). CRISM's objectives are (1) to map the entire surface using a subset of bands to characterize crustal mineralogy, (2) to map the mineralogy of key areas at high spectral and spatial resolution, and (3) to measure spatial and seasonal variations in the atmosphere. These objectives are addressed using three major types of observations. In multispectral mapping mode, with the OSU pointed at planet nadir, data are collected at a subset of 72 wavelengths covering key mineralogic absorptions and binned to pixel footprints of 100 or 200 m/pixel. Nearly the entire planet can be mapped in this fashion. In targeted mode the OSU is scanned to remove most along-track motion, and a region of interest is mapped at full spatial and spectral resolution (15-19 m/pixel, 362-3920 nm at 6.55 nm/channel). Ten additional abbreviated, spatially binned images are taken before and after the main image, providing an emission phase function (EPF) of the site for atmospheric study and correction of surface spectra for atmospheric effects. In atmospheric mode, only the EPF is acquired. Global grids of the resulting lower data volume observations are taken repeatedly throughout the Martian year to measure seasonal variations in atmospheric properties. Raw, calibrated, and map-projected data are delivered to the community with a spectral library to aid in interpretation. C1 Appl Phys Lab, Laurel, MD 20723 USA. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. Inst Astrophys Spatiale, F-91405 Orsay, France. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Space Sci Inst, Boulder, CO 80301 USA. Appl Coherent Technol, Herndon, VA USA. NASA, Jet Propuls Lab, Pasadena, CA 91109 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. Northwestern Univ, Ctr Planetary Sci, Evanston, IL 60208 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Murchie, S (reprint author), Appl Phys Lab, 11100 Johns Hopkins Rd,Room MP3-W165, Laurel, MD 20723 USA. EM scott.murchie@jhuapl.edu RI Murchie, Scott/E-8030-2015; Seelos, Frank/C-7875-2016; McGuire, Patrick/D-2962-2013; Humm, David/B-8825-2016; Smith, Michael/C-8875-2012; Izenberg, Noam/F-3952-2015 OI Murchie, Scott/0000-0002-1616-8751; Seelos, Frank/0000-0001-9721-941X; McGuire, Patrick/0000-0001-6592-4966; Humm, David/0000-0003-1520-261X; Izenberg, Noam/0000-0003-1629-6478 NR 134 TC 353 Z9 356 U1 10 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 30 PY 2007 VL 112 IS E5 AR E05S03 DI 10.1029/2006JE002682 PG 57 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 174NN UT WOS:000246949100001 ER PT J AU Zuber, MT Lemoine, FG Smith, DE Konopliv, AS Smrekar, SE Asmar, SW AF Zuber, Maria T. Lemoine, Frank G. Smith, David E. Konopliv, Alex S. Smrekar, Suzanne E. Asmar, Sami W. TI Mars Reconnaissance Orbiter Radio Science Gravity Investigation SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID GENERAL-CIRCULATION MODEL; GLOBAL SURVEYOR; GRAVITATIONAL-FIELD; INTERIOR STRUCTURE; LASER ALTIMETER; CHANDLER-WOBBLE; MARTIAN CRUST; TOPOGRAPHY; ROTATION; EVOLUTION AB The objectives of the Mars Reconnaissance Orbiter (MRO) Radio Science Gravity Investigation are to improve knowledge of the static structure and characterize the temporal variability of the Martian gravitational field relevant to the planet's internal dynamics, the structure and dynamics of the atmosphere, and the orbital evolution of spacecraft at Mars. The investigation will utilize range rate and range measurements from X-band and, when available, Ka-band tracking systems of the MRO spacecraft. MRO will enable a considerable improvement in the spatial resolution and quality of Mars' global gravity field. The low orbital periapsis of MRO (similar to 255 km) will yield gravity maps suitable for study of regional (similar to 10(2) km) structure of the crust and lithosphere. The addition of tracking data from the Mars Global Surveyor and Mars Odyssey spacecraft, also currently orbiting Mars, will be useful in decorrelating errors in spherical harmonic coefficients of the gravity field that will improve the quality of the static field. Studies of the low-degree gravity field combined with measurements of rotational dynamics will permit insight about the structure of Mars' deep interior. Changes in the low-degree spherical harmonic coefficients of the Martian gravity field and in polar mass anomalies will be used to track the seasonal cycle of CO2 exchange with the surface. Measurements of spacecraft drag will be used to estimate density variations in the atmosphere relevant to weather patterns and aerobraking of future spacecraft. Tracking observations will also be used to improve the ephemeris of Mars and the masses of the Martian moons. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Greenbelt, MD 20771 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. RP Zuber, MT (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, 54-518,77 Massachusetts Ave, Cambridge, MA 02139 USA. EM zuber@mit.edu; frank.lemoine@gsfc.nasa.gov; david.e.smith@nasa.gov; alex.konopliv@jpl.nasa.gov; ssmrekar@jpl.nasa.gov; sami.w.asmar@jpl.nasa.gov RI Lemoine, Frank/D-1215-2013 NR 94 TC 22 Z9 23 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 30 PY 2007 VL 112 IS E5 AR E05S07 DI 10.1029/2006JE002833 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 174NN UT WOS:000246949100003 ER PT J AU Horner-Johnson, BC Gordon, RG Argus, DF AF Horner-Johnson, Benjamin C. Gordon, Richard G. Argus, Donald F. TI Plate kinematic evidence for the existence of a distinct plate between the Nubian and Somalian plates along the Southwest Indian Ridge SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID STATISTICAL TESTS; NORTH AMERICA; MOTION; BOUNDARY; AFRICA; ANTARCTICA; CAPRICORN; LOCATION; CLOSURE; GPS AB [1] Previously, we estimated the angular velocity of the Nubian plate relative to the Somalian plate from an updated set of spreading rates and transform fault azimuths. We found that the Nubia-Somalia plate boundary intersects the Southwest Indian Ridge (SWIR) between approximate to 26 degrees E and approximate to 32 degrees E if both the Nubian and Somalian plates are rigid and if the boundary between them is narrow. These prior results are not completely satisfactory mainly for two reasons: ( 1) The four-plate circuit Somalia-Antarctica-Nubia- Arabia does not close. ( 2) The largest (M-w <= 6.8) recorded "African'' earthquakes that are near, but not along, the SWIR occur near 48 degrees E, well east of the intersection with the Nubia-Somalia boundary. Here we investigate these problems through detailed analysis of plate motion data, especially those along the SWIR east of the Andrew Bain Transform Fault Complex. We find an improved fit to the data and improved plate circuit closure if a region of the African lithosphere is interpreted as a new component plate. This new plate lies between the Nubian and Somalian plates along the SWIR and is separated from the latter by a diffuse boundary that includes the locations of the largest off-ridge earthquakes. Following C. J. H. Hartnady, we call this new plate "Lwandle.'' Use of this new plate geometry shifts the Nubia-Somalia pole of rotation northeastward to just south of South Africa and thus alters estimates of current India-Eurasia plate motion. C1 Rice Univ, Dept Earth Sci, Houston, TX 77005 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Horner-Johnson, BC (reprint author), Rice Univ, Dept Earth Sci, MS-126, Houston, TX 77005 USA. EM ben@rice.edu; rgg@rice.edu; argus@cobra.jpl.nasa.gov RI Argus, Donald/F-7704-2011 NR 22 TC 32 Z9 32 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAY 30 PY 2007 VL 112 IS B5 AR B05418 DI 10.1029/2006JB004519 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 174OB UT WOS:000246950500005 ER PT J AU Kim, JW Hwang, JS von Frese, RRB Kim, HR Lee, SH AF Kim, Jeong Woo Hwang, Jong Sun von Frese, Ralph R. B. Kim, Hyung Rae Lee, Seon-Ho TI Geomagnetic field modeling from satellite attitude control magnetometer measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article AB [1] To demonstrate the utility of satellite attitude control magnetometer measurements for mapping main field variations, we analyzed the three-axis magnetometer (TAM) measurements that provide attitude control for the KOMPSAT-1 satellite. Initial processing involved transforming the TAM's magnetic measurements from the Earth-Centered Inertial coordinates (ECI) to the Earth-Centered Earth-Fixed coordinates (ECEF) and then to spherical coordinates. The magnetic field of the satellite body produces symmetric signatures in the ascending and descending orbital measurements and thus can be readily removed. Spectral correlation filtering of the orbital observations helped to eliminate the dynamic external field and solar activity noise components. The ascending and descending data were then spectrally reconstructed to estimate the total magnetic field with minimum track line noise. Correlation coefficients of 0.97 and 0.96 mark the correlation of the KOMPSAT-1 total geomagnetic intensity map with the Orsted and IGRF2000 core magnetic field models, respectively. Power spectra from Gauss coefficients of KOMPSAT-1 model showed closeness with the models from Orsted data and IGRF2000 model. The spherical harmonic coefficients calculated from the KOMPSAT-1 model by conjugate gradient inversion are strongly coherent with the Orsted and IGRF2000 coefficients through degree 9. C1 Sejong Univ, Dept Geoinformat Engn, Seoul 143747, South Korea. Yonsei Univ, Dept Earth Syst Sci, Seoul 120749, South Korea. Sejong Univ, Geohazard Informat Lab, Seoul, South Korea. Ohio State Univ, Sch Earth Sci, Columbus, OH 43210 USA. NASA, Goddard Space Flight Ctr, Planetary Geodynam Lab,Univ Maryland Baltimore Ct, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. Korea Aerosp Res Inst, Satellite Control Syst Dept, Taejon 305333, South Korea. RP Kim, JW (reprint author), Sejong Univ, Dept Geoinformat Engn, Seoul 143747, South Korea. EM jwkim@sejong.ac.kr NR 25 TC 1 Z9 1 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAY 30 PY 2007 VL 112 IS B5 AR B05105 DI 10.1029/2005JB004042 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 174OB UT WOS:000246950500001 ER PT J AU Tu, JN Song, P Reinisch, BW Green, JL AF Tu, Jiannan Song, Paul Reinisch, Bodo W. Green, James L. TI Smooth electron density transition from plasmasphere to the subauroral region SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETIC-FIELD; PLASMAPAUSE; IMAGE; MAGNETOSPHERE; SATELLITE; INSTABILITY; CONVECTION; RECOVERY; MODEL AB [1] Upper hybrid resonance (UHR) noise band and the nonthermal continuum (NTC) radiation were routinely observed by the radio plasma imager (RPI) onboard the IMAGE satellite when it transited the plasmasphere and subauroral regions. The lower cutoff frequencies of the UHR band and the NTC radiation provide an estimate of the electron plasma frequencies along the satellite orbit. A steep electron density gradient, which defines the plasmapause, was commonly observed when IMAGE transited from the plasmasphere to the subauroral region or vice versa. It appears however that, on many occasions, the electron density transition from the plasmasphere to the subauroral region is smooth without a clear signature of the plasmapause. Such smooth transitions can occur at various magnetic local times. The events presented in this study were observed after geomagnetic activities had been quiet for 2 or more days with Kp primarily less than 3. The smooth density transitions from the plasmasphere to the subauroral region may be an observational evidence of the suggested plasmaspheric wind. C1 Univ Massachusetts, Ctr Atmospher Res, Lowell, MA 01854 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tu, JN (reprint author), Univ Massachusetts, Ctr Atmospher Res, 600 Suffolk St, Lowell, MA 01854 USA. EM jiannan_tu@uml.edu NR 32 TC 21 Z9 21 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 30 PY 2007 VL 112 IS A5 AR A05227 DI 10.1029/2007JA012298 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 174ON UT WOS:000246951800002 ER PT J AU Skowronski, N Clark, K Nelson, R Hom, J Patterson, M AF Skowronski, Nicholas Clark, Kenneth Nelson, Ross Hom, John Patterson, Matt TI Remotely sensed measurements of forest structure and fuel loads in the Pinelands of New Jersey SO REMOTE SENSING OF ENVIRONMENT LA English DT Article; Proceedings Paper CT EastFIRE Conference 2005 CY MAY 11-13, 2005 CL George Mason Univ, Fairfax, VA HO George Mason Univ DE single-beam LIDAR; forest biomass; ladder fuels; fuel loads ID CANOPY; PARAMETERS; INVENTORY; ALTIMETRY AB We used a single-beam, first return profiling LIDAR (Light Detection and Ranging) measurements of canopy height, intensive biometric measurements in plots, and Forest Inventory and Analysis (FIA) data to quantify forest structure and ladder fuels (defined as vertical fuel continuity between the understory and canopy) in the New Jersey Pinelands. The LIDAR data were recorded at 400 Hz over three intensive areas of 1 km(2) where transects were spaced at 200 m, and along 64 transects spaced 1 km apart (total of ca. 2500 km(2)). LIDAR and field measurements of canopy height were similar in the three intensive study areas, with the 80th percentile of LIDAR returns explaining the greatest amount of variability (79%). Correlations between LIDAR data and aboveground tree biomass measured in the field were highly significant when all three 1 km(2) areas were analyzed collectively, with the 80th percentile again explaining the greatest amount of variability (74%). However, when intensive areas were analyzed separately, correlations were poor for Oak/Pine and Pine/Scrub Oak stands. Similar results were obtained using FIA data; at the landscape scale, mean canopy height was positively correlated with aboveground tree biomass, but when forest types were analyzed separately, correlations were significant only for some wetland forest (Pitch Pine lowlands and mixed hardwoods; r(2)=0.74 and 0.59, respectively), and correlations were poor for upland forests (Oak/Pine, Pine/Oak and Pine/Scrub Oak, r(2)=0.33, 0.11 and 0.21, respectively). When LIDAR data were binned into 1-m height classes, more LIDAR pulses were recorded from the lowest height classes in stands with greater shrub biomass, and significant differences were detected between stands where recent prescribed fire treatments had been conducted and unburned areas. Our research indicates that single-beam LIDAR can be used for regional-scale (forest biomass) estimates, but that relationships between height and biomass can be poorer at finer scales within individual forest types. Binned data are useful for estimating the presence of ladder fuels (vertical continuity of leaves and branches) and horizontal fuel continuity below the canopy. (C) 2007 Published by Elsevier Inc. C1 USDA Forest Serv, No Global Change Program, Newtown Sq, PA 19073 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Clark, K (reprint author), USDA Forest Serv, POB 232, New Lisbon, NJ 08064 USA. EM kennethclark@fs.fed.us RI Nelson, Ross/H-8266-2014; Skowronski, Nicholas/N-4417-2013 OI Skowronski, Nicholas/0000-0002-5801-5614 NR 19 TC 53 Z9 55 U1 0 U2 21 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAY 30 PY 2007 VL 108 IS 2 SI SI BP 123 EP 129 DI 10.1016/j.rse.2006.09.032 PG 7 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 168QO UT WOS:000246539300002 ER PT J AU Hao, XJ Qu, JJ AF Hao, Xianjun Qu, John J. TI Retrieval of real-time live fuel moisture content using MODIS measurements SO REMOTE SENSING OF ENVIRONMENT LA English DT Article; Proceedings Paper CT EastFIRE Conference 2005 CY MAY 11-13, 2005 CL George Mason Univ, Fairfax, VA HO George Mason Univ DE live fuel moisture content; remote sensing; wildland fire; leaf model ID LEAF WATER-CONTENT; RADIATIVE-TRANSFER MODELS; REFLECTANCE DATA; VEGETATION FRACTION; INVERSION METHODS; PROSPECT; INDEX; TEMPERATURE; CANOPIES; SOYBEANS AB Live fuel moisture content (LFMC) is one of the most important fuel properties and a critical parameter for wildland fire danger rating estimation and fire behavior analysis. Direct ground measurement of live fuel moisture content has disadvantages of high cost and limited spatial distribution extent. This paper presents an algorithm to retrieve live fuel moisture content from multiple bands of MODIS measurements. We analyzed the physical relationship between surface reflectance and live fuel moisture content using simulated MODIS measurements of diverse leaf samples, derived approximate inversion models, and proposed a semi-physical approach for live fuel moisture retrieval employing multiple MODIS bands. Using simulated MODIS measurements, the correlation coefficients between the true LFMC and estimated LFMC with our inversion models are 0.7738, 0.8397, 0.9560 and 0.9576 respectively. For validation, we tested our inversion method with woody live fuel moisture measurements at fire weather stations in Georgia. The correlation coefficients between measured LFMC and estimated LFNIC with our inversion models are 0.5727, 0.6522, 0.755 1, and 0.7737 respectively. Both model simulation and station measurements demonstrated advantages of our approach in accuracy. Our study suggests the potential for near real-time applications of live fuel moisture. (C) 2006 Elsevier Inc. All rights reserved. C1 George Mason Univ, EastFIRE Lab, CEOSR ESGS, Coll Sci, Fairfax, VA 22030 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hao, XJ (reprint author), George Mason Univ, EastFIRE Lab, CEOSR ESGS, Coll Sci, MS 6C3,4400 Univ Dr, Fairfax, VA 22030 USA. EM xhao1@gmu.edu RI Hao, Xianjun/F-7253-2016; Hao, Xianjun/C-9543-2011 OI Hao, Xianjun/0000-0002-8186-6839; Hao, Xianjun/0000-0002-8186-6839 NR 37 TC 14 Z9 15 U1 0 U2 7 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAY 30 PY 2007 VL 108 IS 2 SI SI BP 130 EP 137 DI 10.1016/j.rse.2006.09.033 PG 8 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 168QO UT WOS:000246539300003 ER PT J AU Wang, WT Qu, JJ Hao, XJ Liu, YQ Sommers, WT AF Wang, Wanting Qu, John J. Hao, Xianjun Liu, Yongqiang Sommers, William T. TI An improved algorithm for small and cool fire detection using MODIS data: A preliminary study in the southeastern United States SO REMOTE SENSING OF ENVIRONMENT LA English DT Article; Proceedings Paper CT EastFIRE Conference 2005 CY MAY 11-13, 2005 CL George Mason Univ, Fairfax, VA HO George Mason Univ DE algorithm; remote sensing; MODIS; regional fire detection; small; cool fires ID HIGH-RESOLUTION RADIOMETER; PRODUCT AB Traditional fire detection algorithms mainly rely on hot spot detection using thermal infrared (TIR) channels with fixed or contextual thresholds. Three solar reflectance channels (0.65 mu m, 0.86 mu m, and 2.1 mu m) were recently adopted into the MODIS version 4 contextual algorithm to improve the active fire detection. In the southeastern United States, where most fires are small and relatively cool, the MODIS version 4 contextual algorithm can be adjusted and improved for more accurate regional fire detection. Based on the MODIS version 4 contextual algorithm and a smoke detection algorithm, an improved algorithm using four TIR channels and seven solar reflectance channels is described. This approach is presented with fire events in the southeastern United States. The study reveals that the T-22 of most small, cool fires undetected by the MODIS version 4 contextual algorithm is lower than 310 K. The improved algorithm is more sensitive to small, cool fires in the southeast especially for fires detected at large scan angles. (C) 2006 Elsevier Inc. All rights reserved. C1 George Mason Univ, Dept Earth Syst & Geoinformat Sci, EastFIRE Lab, ESGS,Coll Sci, Fairfax, VA 22030 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USDA Forest Serv, Forestry Sci Lab, Athens, GA 30602 USA. RP Qu, JJ (reprint author), George Mason Univ, Dept Earth Syst & Geoinformat Sci, EastFIRE Lab, ESGS,Coll Sci, 4400 Univ Dr, Fairfax, VA 22030 USA. EM jqu@scs.gmu.edu RI Hao, Xianjun/F-7253-2016; Hao, Xianjun/C-9543-2011 OI Hao, Xianjun/0000-0002-8186-6839; Hao, Xianjun/0000-0002-8186-6839 NR 27 TC 26 Z9 32 U1 3 U2 9 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAY 30 PY 2007 VL 108 IS 2 SI SI BP 163 EP 170 DI 10.1016/j.rse.2006.11.009 PG 8 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 168QO UT WOS:000246539300006 ER PT J AU Baaske, P Weinert, FM Duhr, S Lemke, KH Russell, MJ Braun, D AF Baaske, Philipp Weinert, Franz M. Duhr, Stefan Lemke, Kono H. Russell, Michael J. Braun, Dieter TI Extreme accumulation of nucleotides in simulated hydrothermal pore systems SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE concentration problem; hydrothermal vents; molecular evolution; origin of life problem; RNA world ID HOT-SPRINGS; LIFE; ORIGIN; EVOLUTION; THERMOPHORESIS; CONVECTION; SEPARATION; EMERGENCE; OLIGOMERS; REDOX AB We simulate molecular transport in elongated hydrothermal pore systems influenced by a thermal gradient. We find extreme accumulation of molecules in a wide variety of plugged pores. The mechanism is able to provide highly concentrated single nucleotides, suitable for operations of an RNA world at the origin of life. It is driven solely by the thermal gradient across a pore. On the one hand, the fluid is shuttled by thermal convection along the pore, whereas on the other hand, the molecules drift across the pore, driven by thermodiffusion. As a result, millimeter-sized pores accumulate even single nucleotides more than 10(8)-fold into micrometer-sized regions. The enhanced concentration of molecules is found in the bulk water near the closed bottom end of the pore. Because the accumulation depends exponentially on the pore length and temperature difference, it is considerably robust with respect to changes in the cleft geometry and the molecular dimensions. Whereas thin pores can concentrate only long polynucleotides, thicker pores accumulate short and long polynucleotides equally well and allow various molecular compositions. This setting also provides a temperature oscillation, shown previously to exponentially replicate DNA in the protein-assisted PCR. Our results indicate that, for life to evolve, complicated active membrane transport is not required for the initial steps. We find that interlinked mineral pores in a thermal gradient provide a compelling high-concentration starting point for the molecular evolution of life. C1 Univ Munich, Dept Biophys, D-80799 Munich, Germany. Swiss Fed Inst Technol, Geochem Grp, Inst Mineral & Petrol, CH-8092 Zurich, Switzerland. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Braun, D (reprint author), Univ Munich, Dept Biophys, Amalienstr 54, D-80799 Munich, Germany. EM dieter.braun@physik.lmu.de NR 41 TC 145 Z9 148 U1 4 U2 57 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 29 PY 2007 VL 104 IS 22 BP 9346 EP 9351 DI 10.1073/pnas.0609592104 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 174IN UT WOS:000246935700048 PM 17494767 ER PT J AU Li, JV Chuang, SL Aifer, E Jackson, EM AF Li, Jian V. Chuang, Shun Lien Aifer, Edward Jackson, Eric M. TI Surface recombination velocity reduction in type-II InAs/GaSb superlattice photodiodes due to ammonium sulfide passivation SO APPLIED PHYSICS LETTERS LA English DT Article ID INAS/GA1-XINXSB SUPERLATTICE; INFRARED PHOTODIODES; ELECTRONS AB The surface recombination velocity (SRV) of minority electrons in a type-II InAs/GaSb superlattice photodiode is quantitatively investigated using the electron beam induced current technique and its value used to evaluate the effects of two different passivation methods. Before passivation, the SRV was determined to be (5.0 +/- 0.2)x10(4) cm/s. The SRVs of two samples passivated at room temperature are compared with that of the unpassivated sample. One passivation method, using a neutralized (NH4)(2)S solution for 60 min, reduces the SRV by a factor of 2. The other passivation method, using 4% (NH4)(2)S solution for 30 min, reduces the SRV by more than one order of magnitude. (C) 2007 American Institute of Physics. C1 Univ Illinois, Dept Elect & Comp Engn, Urbana, IL 61801 USA. USN, Res Lab, Washington, DC 20375 USA. SFA Inc, Largo, MD 20774 USA. RP Li, JV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM s-chuang@uiuc.edu RI Li, Jian/B-1627-2016 NR 13 TC 9 Z9 9 U1 1 U2 9 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 28 PY 2007 VL 90 IS 22 AR 223503 DI 10.1063/1.2743905 PG 3 WC Physics, Applied SC Physics GA 173ZB UT WOS:000246909900081 ER PT J AU Khakoo, MA Wang, S Laher, R Johnson, PV Malone, CP Kanik, I AF Khakoo, M. A. Wang, S. Laher, R. Johnson, P. V. Malone, C. P. Kanik, I. TI Direct evidence for channel-coupling effects in molecules: electron impact excitation of the a ''(1)Sigma(+)(g) state of N-2 SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID DIFFERENTIAL CROSS-SECTIONS; SCATTERING; ENERGIES; NITROGEN; MERCURY; HELIUM; TRANSITIONS; C3-PI-U; 6S6P; N2 AB New measurements of differential cross-sections for excitation of the a'' (1) Sigma(+)(g) (v' = 0, 1) state in molecular nitrogen reveal a cusp-like angular distribution. This feature is distinctly observed for the first time in the present electron energy-loss experiment as a result of finer scattering angle grid and impact energy coverage than previous measurements. This feature is similar to that observed in atomic targets such as He, Hg and Ba. The observed phenomenon suggests an interference effect related to configuration-interaction coupling between lower and excited states that are of the same symmetry. It is hoped that the present work will stimulate theoretical investigations into the physics that governs this cusp-like behaviour. C1 Calif State Univ Fullerton, Dept Phys, Fullerton, CA 92831 USA. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Khakoo, MA (reprint author), Calif State Univ Fullerton, Dept Phys, Fullerton, CA 92831 USA. RI Malone, Charles/A-6294-2010; Wang, Shiyang/C-1729-2012; Johnson, Paul/D-4001-2009 OI Malone, Charles/0000-0001-8418-1539; Johnson, Paul/0000-0002-0186-8456 NR 33 TC 9 Z9 9 U1 0 U2 7 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD MAY 28 PY 2007 VL 40 IS 10 BP F167 EP F173 DI 10.1088/0953-4075/40/10/F01 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 168VK UT WOS:000246551900001 ER PT J AU Savchenkov, AA Matsko, AB Ilchenko, VS Maleki, L AF Savchenkov, Anatoliy A. Matsko, Andrey B. Ilchenko, Vladimir S. Maleki, Lute TI Optical resonators with ten million finesse SO OPTICS EXPRESS LA English DT Article ID CAF2; SPECTROSCOPY; SCATTERING; CRYSTALS; LOSSES; LASER AB We report a significant improvement of the finesse and quality factor of a calcium fluoride whispering gallery mode optical resonator achieved with iterative thermal annealing. The initial and final values of the resonator finesse are F-i approximate to 5 x 10(5) and F-f >= 10(7) respectively. The measurements are conducted at room temperature in the laboratory atmosphere. (C) 2007 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Savchenkov, AA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 298-100, Pasadena, CA 91109 USA. EM Andrey.Matsko@jpl.nasa.gov RI Matsko, Andrey/A-1272-2007 NR 22 TC 137 Z9 137 U1 7 U2 36 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD MAY 28 PY 2007 VL 15 IS 11 BP 6768 EP 6773 DI 10.1364/OE.15.006768 PG 6 WC Optics SC Optics GA 178SL UT WOS:000247240300027 PM 19546987 ER PT J AU Mohageg, M Savchenkov, AA Ilchenko, VS Maleki, L AF Mohageg, Makan Savchenkov, Anatoliy A. Ilchenko, Vladimir S. Maleki, Lute TI Measurement of the far field intensity distribution of a bent and cleaved fiber taper SO OPTICS EXPRESS LA English DT Article ID FABRICATION AB We have theoretically predicted and experimentally demonstrated mode conversion in fiber tapers subject to large adiabatic bending. The far field intensity distribution of the taper mode is imaged in part by cleaving the taper at the position of minimum diameter. (C) 2007 Optical Society of America C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mohageg, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM makan.mohageg@jpl.nasa.gov NR 11 TC 0 Z9 0 U1 1 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD MAY 28 PY 2007 VL 15 IS 11 BP 6988 EP 6993 DI 10.1364/OE.15.006988 PG 6 WC Optics SC Optics GA 178SL UT WOS:000247240300054 PM 19547014 ER PT J AU Chai, TF Carmichael, GR Tang, YH Sandu, A Hardesty, M Pilewskie, P Whitlow, S Browell, EV Avery, MA Nedelec, P Merrill, JT Thompson, AM Williams, E AF Chai, Tianfeng Carmichael, Gregory R. Tang, Youhua Sandu, Adrian Hardesty, Michael Pilewskie, Peter Whitlow, Sallie Browell, Edward V. Avery, Melody A. Nedelec, Philippe Merrill, John T. Thompson, Anne M. Williams, Eric TI Four-dimensional data assimilation experiments with International Consortium for Atmospheric Research on Transport and Transformation ozone measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ADJOINT SENSITIVITY-ANALYSIS; VARIATIONAL STATISTICAL-ANALYSIS; BOUND-CONSTRAINED OPTIMIZATION; CHEMISTRY DATA ASSIMILATION; CHEMICAL KINETIC SYSTEMS; MOZAIC AIRBORNE PROGRAM; RECURSIVE FILTERS; NUMERICAL ASPECTS; TRACE-P; PART I AB [ 1] Ozone measurements by various platforms during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) operations in the summer of 2004 are assimilated into the STEM regional chemical transport model (CTM). Under the four-dimensional variational data assimilation (4D-Var) framework, the model forecast ( background) error covariance matrix is constructed using both the so-called NMC ( National Meteorological Center, now National Centers for Environmental Prediction) method and the observational (Hollingworth-Lonnberg) method. The inversion of the covariance matrix is implemented using truncated singular value decomposition (TSVD) approach. The TSVD approach is numerically stable even with severely ill conditioned vertical correlation covariance matrix and large horizontal correlation distances. Ozone observations by different platforms ( aircraft, surface, and ozonesondes) are first assimilated separately. The impacts of the various measurements are evaluated on their ability to improve the predictions, defined as the information content of the observations under the current framework. In the end, all observations are assimilated into the CTM. The final analysis matches well with observations from all platforms. Assessed with all the observations throughout the boundary layer and midtroposphere, the model bias is reduced from 11.3 ppbv for the base case to - 1.5 ppbv. A reduction of 10.3 ppbv in root mean square error is also seen. In addition, the potential of improving air quality forecasts by chemical data assimilation is demonstrated. The effect of assimilating ozone observations on model predictions of other species is also shown. C1 Univ Iowa, Ctr Global & Reg Environm Res, Iowa City, IA 52246 USA. Virginia Polytech Inst & State Univ, Dept Comp Sci, Blacksburg, VA 24061 USA. NOAA, Environm Technol Lab, Boulder, CO USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Climate Change Res Ctr, Durham, NH 03824 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. CNRS, Lab Aerol, F-31400 Toulouse, France. Univ Rhode Isl, Grad Sch Oceanog, Ctr Atmospher Chem Studies, Narragansett, RI 02882 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Div Chem Sci, Earth Syst Res Lab, Boulder, CO 80305 USA. RP Chai, TF (reprint author), Univ Iowa, Ctr Global & Reg Environm Res, 429 IATL, Iowa City, IA 52246 USA. EM tchai@cgrer.uiowa.edu RI Chai, Tianfeng/E-5577-2010; Hardesty, Robert/H-9844-2013; Williams, Eric/F-1184-2010; Tang, Youhua/D-5205-2016; Thompson, Anne /C-3649-2014; Manager, CSD Publications/B-2789-2015 OI Chai, Tianfeng/0000-0003-3520-2641; Tang, Youhua/0000-0001-7089-7915; Thompson, Anne /0000-0002-7829-0920; NR 41 TC 48 Z9 48 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 26 PY 2007 VL 112 IS D12 AR D12S15 DI 10.1029/2006JD007763 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 173AZ UT WOS:000246847200001 ER PT J AU Miller, CE Crisp, D DeCola, PL Olsen, SC Randerson, JT Michalak, AM Alkhaled, A Rayner, P Jacob, DJ Suntharalingam, P Jones, DBA Denning, AS Nicholls, ME Doney, SC Pawson, S Boesch, H Connor, BJ Fung, IY O'Brien, D Salawitch, RJ Sander, SP Sen, B Tans, P Toon, GC Wennberg, PO Wofsy, SC Yung, YL Law, RM AF Miller, C. E. Crisp, D. DeCola, P. L. Olsen, S. C. Randerson, J. T. Michalak, A. M. Alkhaled, A. Rayner, P. Jacob, D. J. Suntharalingam, P. Jones, D. B. A. Denning, A. S. Nicholls, M. E. Doney, S. C. Pawson, S. Boesch, H. Connor, B. J. Fung, I. Y. O'Brien, D. Salawitch, R. J. Sander, S. P. Sen, B. Tans, P. Toon, G. C. Wennberg, P. O. Wofsy, S. C. Yung, Y. L. Law, R. M. TI Precision requirements for space-based X-CO2 data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID IN-SITU OBSERVATIONS; ATMOSPHERIC CARBON-DIOXIDE; EMPIRICAL AGE SPECTRA; REFLECTED SUNLIGHT; 3-DIMENSIONAL TRANSPORT; DIFFERENTIAL ABSORPTION; AIRCRAFT OBSERVATION; GLOBAL OBSERVATIONS; WESTERN PACIFIC; NORTH PACIFIC AB [1] Precision requirements are determined for space-based column-averaged CO2 dry air mole fraction (X-CO2) data. These requirements result from an assessment of spatial and temporal gradients in X-CO2, the relationship between X-CO2 precision and surface CO2 flux uncertainties inferred from inversions of the X-CO2 data, and the effects of X-CO2 biases on the fidelity of CO2 flux inversions. Observational system simulation experiments and synthesis inversion modeling demonstrate that the Orbiting Carbon Observatory mission design and sampling strategy provide the means to achieve these X-CO2 data precision requirements. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA Headquarters, Sci Mission Directorate, Washington, DC USA. Los Alamos Natl Lab, Los Alamos, NM USA. Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA USA. Univ Michigan, Dept Civil & Environm Engn, Ann Arbor, MI 48109 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. UVSQ, CNRS, CEA, Lab Sci Climat & Environm IPSL, Gif Sur Yvette, France. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Univ Toronto, Dept Phys, Toronto, ON, Canada. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Woods Hole Oceanog Inst, Dept Marine Chem & Geochem, Woods Hole, MA 02543 USA. Goddard Earth Sci & Technol Ctr, Baltimore, MD USA. NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. Natl Inst Water & Atmospher Res, Omakau, New Zealand. Univ Calif Berkeley, Berkeley Atmospher Sci Ctr, Berkeley, CA 94720 USA. NOAA, Earth Syst Res Lab, Global Monitoring Div, Boulder, CO USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. CSIRO Marine & Atmospher Res, Aspendale, Vic, Australia. RP Miller, CE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM charles.e.miller@jpl.nasa.gov RI Salawitch, Ross/B-4605-2009; Law, Rachel/A-1969-2012; Wennberg, Paul/A-5460-2012; Doney, Scott/F-9247-2010; Denning, Scott/F-4974-2011; Jones, Dylan/O-2475-2014; Boesch, Hartmut/G-6021-2012; Pawson, Steven/I-1865-2014 OI Salawitch, Ross/0000-0001-8597-5832; Law, Rachel/0000-0002-7346-0927; Doney, Scott/0000-0002-3683-2437; Denning, Scott/0000-0003-3032-7875; Jones, Dylan/0000-0002-1935-3725; Pawson, Steven/0000-0003-0200-717X NR 58 TC 167 Z9 169 U1 1 U2 44 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 26 PY 2007 VL 112 IS D10 AR D10314 DI 10.1029/2006JD007659 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 173AV UT WOS:000246846800004 ER PT J AU Sakerin, SM Smirnov, A Kabanov, DM Pol'kin, VV Panchenko, MV Holben, BN Kopelevich, OV AF Sakerin, S. M. Smirnov, A. Kabanov, D. M. Pol'kin, V. V. Panchenko, M. V. Holben, B. N. Kopelevich, O. V. TI Aerosol optical and microphysical properties over the Atlantic Ocean during the 19th cruise of the Research Vessel Akademik Sergey Vavilov SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; DEPTH MEASUREMENTS; SEA-SALT; ATMOSPHERIC AEROSOL; SIZE DISTRIBUTIONS; SUN PHOTOMETERS; BLACK CARBON; WIND-SPEED; PARTICLES; MODEL AB [1] This paper presents aerosol optical depths in the total atmospheric column, aerosol size distributions, number concentrations and black carbon mass concentrations at the deck level measured in October-December 2004 on board the R/V Akademik Sergey Vavilov. Aerosol optical depths measured within the spectral range 0.34-4.0 mm were close to background oceanic conditions (similar to 0.04-0.08) in the high-latitude southern Atlantic. Angstrom parameters derived within 440-870 nm and 870-2150 nm spectral ranges did not exceed 0.6, yielding averages of 0.34 and 0.12, respectively. The mass concentration of black carbon varied within the range 0.02-0.08 mu g/m(3) in the 34-55 degrees S latitudinal belt. The average of 0.04 mu g/m(3) (s.d. similar to 0.015) is close to the reported results for the remote areas of the South Indian Ocean. Aerosol volume size distributions measured within the size range of 0.4-10 mu m can be characterized by a geometric volume mean radius similar to 3 mu m. This is consistent with the columnar retrievals reported by the Aerosol Robotic Network (AERONET). C1 Russian Acad Sci, Inst Atmospher Opt, Siberian Branch, Tomsk 634055, Russia. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Russian Acad Sci, PP Shirshov Inst Oceanol, Moscow 117997, Russia. RP Sakerin, SM (reprint author), Russian Acad Sci, Inst Atmospher Opt, Siberian Branch, Tomsk 634055, Russia. EM asmirnov@aeronet.gsfc.nasa.gov RI Smirnov, Alexander/C-2121-2009; Kopelevich, Oleg/G-2248-2014 OI Smirnov, Alexander/0000-0002-8208-1304; Kopelevich, Oleg/0000-0002-3697-3387 NR 46 TC 7 Z9 11 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 26 PY 2007 VL 112 IS D10 AR D10220 DI 10.1029/2006JD007947 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 173AV UT WOS:000246846800010 ER PT J AU Sanny, J Judnick, D Moldwin, MB Berube, D Sibeck, DG AF Sanny, J. Judnick, D. Moldwin, M. B. Berube, D. Sibeck, D. G. TI Global profiles of compressional ultralow frequency wave power at geosynchronous orbit and their response to the solar wind SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTERPLANETARY MAGNETIC-FIELD; SYNCHRONOUS ORBIT; MAGNETOSPHERIC PULSATIONS; GEOMAGNETIC-ACTIVITY; SEMIANNUAL VARIATION; HIGH-LATITUDES; LONG-PERIOD; ULF WAVES; DEPENDENCE; VELOCITY AB [1] We investigate the global local-time profiles of compressional wave power in three ultralow frequency (ULF) bands corresponding to Pc3, Pc4, and Pc5 pulsations using magnetic field data from the geosynchronous GOES satellites. The global power profiles of the three frequency bands are studied for low, moderate, and high levels of geomagnetic activity based on the Dst index. We also consider the seasonal variation of the ULF power profiles, as well as the effects of solar wind and interplanetary magnetic field ( IMF) parameters. For high geomagnetic activity, we find that the greatest power is associated with compressional Pc5 pulsations in the afternoon sector; for low geomagnetic activity, ULF power levels are consistently highest in the tail region. A summer power minimum in all three frequency bands is observed in our study of seasonal variation, while higher power levels occur around local midnight throughout the year. The enhancement of ULF power by high solar wind velocity and pressure is greater for the lower-frequency waves. Furthermore, solar wind plasma parameters have a significantly greater influence on ULF wave power than IMF parameters like cone angle and northward/southward orientation. C1 Loyola Marymount Univ, Dept Phys, Los Angeles, CA 90045 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sanny, J (reprint author), Loyola Marymount Univ, Dept Phys, Los Angeles, CA 90045 USA. EM jsanny@lmu.edu RI Moldwin, Mark/F-8785-2011; Sibeck, David/D-4424-2012 OI Moldwin, Mark/0000-0003-0954-1770; NR 35 TC 6 Z9 6 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 26 PY 2007 VL 112 IS A5 AR A05224 DI 10.1029/2006JA012046 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 173CE UT WOS:000246850300004 ER PT J AU Young, LH Benson, DR Montanaro, WM Lee, SH Pan, LL Rogers, DC Jensen, J Stith, JL Davis, CA Campos, TL Bowman, KP Cooper, WA Lait, LR AF Young, Li-Hao Benson, David R. Montanaro, William M. Lee, Shan-Hu Pan, Laura L. Rogers, David C. Jensen, Jorgen Stith, Jeffrey L. Davis, Christopher A. Campos, Teresa L. Bowman, Kenneth P. Cooper, William A. Lait, Leslie R. TI Enhanced new particle formation observed in the northern midlatitude tropopause region SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID UPPER TROPOSPHERE; SIZE DISTRIBUTION; NUMBER CONCENTRATION; CONDENSATION NUCLEI; LOWER STRATOSPHERE; AEROSOL-PARTICLES; MIXING PROCESSES; AIRCRAFT; NUCLEATION; GROWTH AB [1] The free troposphere and lower stratosphere is a source region for new particle formation. In particular, nucleation can be active near the tropopause because of low temperatures. Here we show enhanced new particle formation observed during midlatitude tropopause folds. Number concentrations and size distributions of particles with diameters from 4 to 2000 nm were measured in the midlatitude tropopause region on 1 and 7 December 2005 during the NSF/NCAR GV Progressive Science Missions. High number concentrations of ultrafine particles with diameters from 4 to 9 nm, ranging from similar to 700 to 3960 cm(-3), were measured during tropopause folds. Our observations show that stratospheric and tropospheric air exchange during tropopause folding events, with a large gradient of temperature and relative humidity, may have enhanced new particle formation. Our results are consistent with other modeling predictions showing that nucleation rates are increased with mixing of two air masses with different temperatures and relative humidities. In addition, new particle formation events were also associated with vertical motion that may also have brought higher concentrations of water vapor and aerosol precursors ( that originate at the ground level) from lower altitudes to higher altitudes where temperatures and surface areas are lower. The average ultrafine particle concentrations for the regions that were not affected by tropopause folds were also high (> 100 cm(-3)), indicating that nucleation is active in the tropopause region, in general. Our results suggest that atmospheric dynamics, such as stratosphere and troposphere exchange and vertical motion, affect new particle formation in this region. C1 Kent State Univ, Dept Chem, Kent, OH 44240 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Natl Ctr Atmospher Res, Res Aviat Facil, Broomfield, CO USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Young, LH (reprint author), Kent State Univ, Dept Chem, 302 Williams Hall Kent, Kent, OH 44240 USA. EM slee19@kent.edu RI Pan, Laura/A-9296-2008; Jensen, Jorgen/C-9211-2009; Bowman, Kenneth/A-1345-2012; Lee, Shan-Hu/F-9913-2014; OI Pan, Laura/0000-0001-7377-2114; Bowman, Kenneth/0000-0002-2667-8632; Young, Li-Hao/0000-0002-3328-8181 NR 39 TC 25 Z9 27 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 25 PY 2007 VL 112 IS D10 AR D10218 DI 10.1029/2006JD008109 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 173AT UT WOS:000246846600002 ER PT J AU Raj, SV Ghosn, LJ Robinson, C Humphrey, D AF Raj, S. V. Ghosn, L. J. Robinson, C. Humphrey, D. TI High heat flux exposures of coated GRCop-84 substrates SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE coatings; vacuum plasma spray; space launch vehicles; hydrogen-oxygen test; copper alloys ID COATINGS AB The performance of several overlay coatings on Cu-8 at. %Cr4%Nb alloy (GRCop-84) thermally cycled in a high heat flux hydrogen-oxygen combustion flame are reported. Finite element analyses (FEA) were conducted to evaluate the expected performances of coatings with different thermal conductivities as well as to determine a suitable thickness for coating deposition. Top coats consisting of Cu-26%Cr, NiAl and NiCrAlY along with a Cu-8%Cr bond coat were vacuum plasma sprayed on GRCop-84 thin sheet specimens. It was observed that the Cu-26%Cr coating formed blisters whereas the NiAl and NiCrAlY coatings showed no significant differences between the exposed and unexposed specimens. Water-cooled rectangular specimens specially designed to simulate a rocket engine liner were coated with a NiCrAlY-top coat using either a Cu-8%Cr or a Cu-8%Cr-1%Al bond coat. Preliminary tests conducted on these specimens showed no visible evidence of coating spallation after 40 cycles. The measured temperatures and heat fluxes were used in FEA models to estimate the stresses, strains and temperatures across the coating interfaces in these specimens. Published by Elsevier B.V. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Cleveland, OH 44135 USA. QSS Grp Inc, Cleveland, OH 44135 USA. ASRC Aerosp, Cleveland, OH 44135 USA. RP Raj, SV (reprint author), NASA, Glenn Res Ctr, MS 106-5,21000 Brookpk Rd, Cleveland, OH 44135 USA. EM sai.v.raj@nasa.gov NR 20 TC 10 Z9 10 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD MAY 25 PY 2007 VL 457 IS 1-2 BP 300 EP 312 DI 10.1016/j.msea.2006.12.133 PG 13 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 164ES UT WOS:000246216900044 ER PT J AU Posner, A AF Posner, Arik TI Up to 1-hour forecasting of radiation hazards from solar energetic ion events with relativistic electrons SO SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS LA English DT Article ID PARTICLE EVENTS; MAGNETIC-FIELD; INTERPLANETARY SHOCKS; ACCELERATION; SUN; FLARES; ABUNDANCES; DEPENDENCE; PLASMA; CORONA AB [1] The sudden and prompt occurrence of solar energetic particle events poses a hazard to manned space activities and interferes with robotic space science missions. This study demonstrates the possibility of short-term forecasting of the appearance and intensity of solar ion events by means of relativistic, near-light speed electrons. A list of the most severe proton events measured by GOES 8 in the years 1996-2002 serves as a basis to derive the fundamentals of the forecasting method with statistical and superposed epoch techniques. The Comprehensive Suprathermal and Energetic Particle Analyzer (COSTEP) on SOHO provides relativistic electron and < 50 MeV proton observations at 1 AU. With a subset of solar particle events (SPEs) where the location of the associated flare on the Sun has been determined, we find that ( 1) relativistic electrons always arrive at 1 AU ahead of nonrelativistic SPEs allowing their forecasting; ( 2) the intensity increase of both, electrons and protons alike, depends on the magnetic connection, i.e., the magnetic longitude difference between the observer and the flare; and ( 3) as coming from one source under near-identical propagation conditions, significant correlations exist that show that the early electron intensity and increase can be utilized as a matrix to forecast the upcoming proton intensity. The study demonstrates one initial empirical forecasting technique with electron and proton observations in 2003. C1 [Posner, Arik] SW Res Inst, San Antonio, TX 78238 USA. [Posner, Arik] NASA Headquarters, Washington, DC USA. RP Posner, A (reprint author), SW Res Inst, 6220 Culebra Rd, San Antonio, TX 78238 USA. EM aposner@swri.org OI Posner, Arik/0000-0003-1572-8734 NR 54 TC 37 Z9 37 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 1542-7390 J9 SPACE WEATHER JI Space Weather PD MAY 25 PY 2007 VL 5 IS 5 AR S05001 DI 10.1029/2006SW000268 PG 28 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 261JC UT WOS:000253073900001 ER PT J AU Limpasuvan, V Wu, DL Alexander, MJ Xue, M Hu, M Pawson, S Perkins, JR AF Limpasuvan, Varavut Wu, Dong L. Alexander, M. Joan Xue, Ming Hu, Ming Pawson, Steven Perkins, James R. TI Stratospheric gravity wave simulation over Greenland during 24 January 2005 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NONHYDROSTATIC ATMOSPHERIC SIMULATION; FLUX-PROFILE RELATIONSHIPS; PREDICTION SYSTEM ARPS; SURFACE PROCESSES; MESOSCALE MODEL; MOUNTAIN WAVES; PARAMETERIZATION; GENERATION; ATLANTIC; CLOUDS AB [ 1] The "Advanced Regional Prediction System'' forecast model is extended up to the stratopause and over the entire hemisphere to simulate gravity waves during 24 January 2005. With a 15-km horizontal resolution, the simulation produces dominant gravity wave features near Eastern Greenland that are associated mainly with orographic forcing by the Greenland terrain. The simulated wave temperature perturbations compare favorably with radiance perturbations from NASA Atmospheric Infrared Sounder observations. In the upper stratosphere ( 40 - 50 km), vertical overturning of the isentropes suggests the occurrence of wave breaking just east of Greenland that leads to a tremendous reduction of wave amplitudes. The associated flux divergence produces horizontal flow deceleration of 12 - 120 m s(-1) day(-1) and coincides with areas of depleted stratospheric wind speed, suggesting strong interactions between orographic gravity waves and the polar vortex. A simulation using the coarser 50-km horizontal resolution produces gravity waves of significantly weaker amplitudes. C1 Coastal Carolina Univ, Dept Chem & Phys, Conway, SC 29528 USA. CALTECH, NASA Jet Prop Lab, Pasadena, CA USA. NW Res Associates Inc, Colorado Res Associate Div, Boulder, CO USA. Univ Oklahoma, Ctr Anal & Predict Storms, Norman, OK 73019 USA. NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. Coastal Carolina Univ, Dept Comp Sci, Conway, SC USA. RP Limpasuvan, V (reprint author), Coastal Carolina Univ, Dept Chem & Phys, POB 261954, Conway, SC 29528 USA. EM var@coastal.edu RI Xue, Ming/F-8073-2011; Limpasuvan, Varavut/K-6266-2013; Wu, Dong/D-5375-2012; Pawson, Steven/I-1865-2014 OI Xue, Ming/0000-0003-1976-3238; Pawson, Steven/0000-0003-0200-717X NR 53 TC 17 Z9 17 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 24 PY 2007 VL 112 IS D10 AR D10115 DI 10.1029/2006JD007823 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 173AS UT WOS:000246846500007 ER PT J AU Pope, FD Hansen, JC Bayes, KD Friedl, RR Sander, SP AF Pope, Francis D. Hansen, Jaron C. Bayes, Kyle D. Friedl, Randall R. Sander, Stanley P. TI Ultraviolet absorption spectrum of chlorine peroxide, ClOOCl SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID GAUSSIAN DISTRIBUTION FUNCTION; CROSS-SECTIONS; SELF-REACTION; TEMPERATURE-DEPENDENCE; ATMOSPHERIC OXIDATION; 250 NM; RADICALS; DIMER; PHOTOLYSIS; KINETICS AB The photolysis of chlorine peroxide (ClOOCl) is understood to be a key step in the destruction of polar stratospheric ozone. This study generated and purified ClOOCl in a novel fashion, which resulted in spectra with low impurity levels and high peak absorbances. The ClOOCl was generated by laser photolysis of Cl(2) in the presence of ozone, or by photolysis of ozone in the presence of CF(2)Cl(2). The product ClOOCl was collected, along with small amounts of impurities, in a trap at about -125 degrees C. Gas-phase ultraviolet spectra were recorded using a long path cell and spectrograph/diode array detector as the trap was slowly warmed. The spectrum of ClOOCl could be fit with two Gaussian-like expressions, corresponding to two different electronic transitions, having similar energies but different widths. The energies and band strengths of these two transitions compare favorably with previous ab initio calculations. The cross sections of ClOOCl at wavelengths longer than 300 nm are significantly lower than all previous measurements or estimates. These low cross sections in the photolytically active region of the solar spectrum result in a rate of photolysis of ClOOCl in the stratosphere that is much lower than currently recommended. For conditions representative of the polar vortex (solar zenith angle of 86(o), 20 km altitude, and O(3) and temperature profiles measured in March 2000) calculated photolysis rates are a factor of 6 lower than the current JPL/NASA recommendation. This large discrepancy calls into question the completeness of present atmospheric models of polar ozone depletion. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bayes, KD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM kdbayes@jpl.nasa.gov RI Pope, Francis/F-8552-2012 OI Pope, Francis/0000-0001-6583-8347 NR 46 TC 59 Z9 61 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 24 PY 2007 VL 111 IS 20 BP 4322 EP 4332 DI 10.1021/jp067660w PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 169CC UT WOS:000246569300027 PM 17474723 ER PT J AU Vaddiraju, S Sunkara, MK Chin, AH Ning, CZ Dholakia, GR AF Vaddiraju, S. Sunkara, M. K. Chin, A. H. Ning, C. Z. Dholakia, G. R. TI Synthesis of group III antimonide nanowires SO JOURNAL OF PHYSICAL CHEMISTRY C LA English DT Article ID BULK SYNTHESIS; GROWTH; GASB; SEMICONDUCTORS; LASERS AB Synthesis of nanowires of Group III antimonides (GaSb and InSb) is studied in detail using two approaches: (i) direct antimonidization of Group III metal droplets and (ii) reactive vapor transport of Group III metals in the presence of antimony in the vapor phase. The diameter of the GaSb nanowires ranged from 30 to 700 nm and length from a few to hundreds of micrometers. GaSb nanowires as long as 1 millimeter have been synthesized using direct antimonidization of large (several millimeters) sized gallium droplets. Reactive vapor transport of Group III metals in the presence of antimony in the vapor phase led to the formation of homoepitaxially oriented GaSb nanowire arrays on top of GaSb crystals. In the case of InSb, 100-nm-thick nanowires were obtained by direct antimonidization of indium droplets. Optical and electrical measurements of the GaSb nanowires, performed using photoluminescence and scanning tunneling spectroscopy, reveal a band gap of similar to 0.72 eV, similar to that of bulk GaSb. C1 Univ Louisville, Dept Chem Engn, Louisville, KY 40292 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Arizona State Univ, Dept Elect Engn, Tempe, AZ 85287 USA. Arizona State Univ, Ctr Nanophoton, Tempe, AZ 85287 USA. RP Sunkara, MK (reprint author), Univ Louisville, Dept Chem Engn, Louisville, KY 40292 USA. EM mahendra@louisville.edu; cning@asu.edu RI Sunkara, Mahendra/A-3033-2008; Ning, C. Z./D-4699-2009 OI Ning, C. Z./0000-0003-4583-8889 NR 25 TC 43 Z9 44 U1 0 U2 39 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1932-7447 J9 J PHYS CHEM C JI J. Phys. Chem. C PD MAY 24 PY 2007 VL 111 IS 20 BP 7339 EP 7347 DI 10.1021/jp068943r PG 9 WC Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary SC Chemistry; Science & Technology - Other Topics; Materials Science GA 169CH UT WOS:000246569800018 ER PT J AU Crucian, B Lee, P Stowe, R Jones, J Effenhauser, R Widen, R Sams, C AF Crucian, Brian Lee, Pascal Stowe, Raymond Jones, Jeff Effenhauser, Rainer Widen, Raymond Sams, Clarence TI Immune system changes during simulated planetary exploration on Devon Island, high arctic SO BMC IMMUNOLOGY LA English DT Article ID EPSTEIN-BARR-VIRUS; CELL-MEDIATED-IMMUNITY; SHORT-TERM SPACEFLIGHT; SPACE-FLIGHT; CYTOKINE PRODUCTION; ANTARCTIC WINTER; T-LYMPHOCYTES; SIGNAL-TRANSDUCTION; PERIPHERAL-BLOOD; FLOW-CYTOMETRY AB Background: Dysregulation of the immune system has been shown to occur during spaceflight, although the detailed nature of the phenomenon and the clinical risks for exploration class missions have yet to be established. Also, the growing clinical significance of immune system evaluation combined with epidemic infectious disease rates in third world countries provides a strong rationale for the development of field- compatible clinical immunology techniques and equipment. In July 2002 NASA performed a comprehensive immune assessment on field team members participating in the Haughton-Mars Project (HMP) on Devon Island in the high Canadian Arctic. The purpose of the study was to evaluate the effect of mission-associated stressors on the human immune system. To perform the study, the development of techniques for processing immune samples in remote field locations was required. Ten HMP-2002 participants volunteered for the study. A field protocol was developed at NASA-JSC for performing sample collection, blood staining/processing for immunophenotype analysis, whole-blood mitogenic culture for functional assessments and cell-sample preservation on-location at Devon Island. Specific assays included peripheral leukocyte distribution; constitutively activated T cells, intracellular cytokine profiles, plasma cortisol and EBV viral antibody levels. Study timepoints were 30 days prior to mission start, mid-mission and 60 days after mission completion. Results: The protocol developed for immune sample processing in remote field locations functioned properly. Samples were processed on Devon Island, and stabilized for subsequent analysis at the Johnson Space Center in Houston. The data indicated that some phenotype, immune function and stress hormone changes occurred in the HMP field participants that were largely distinct from pre-mission baseline and post-mission recovery data. These immune changes appear similar to those observed in astronauts following spaceflight. Conclusion: The immune system changes described during the HMP field deployment validate the use of the HMP as a ground-based spaceflight/planetary exploration analog for some aspects of human physiology. The sample processing protocol developed for this study may have applications for immune studies in remote terrestrial field locations. Elements of this protocol could possibly be adapted for future in-flight immunology studies conducted during space missions. C1 NASA, Lyndon B Johnson Space Ctr, Wyle Labs, Houston, TX 77058 USA. SETI Inst, Mars Inst, Mountain View, CA 94043 USA. NASA, Ames Res Ctr, Mountain View, CA 94043 USA. Microgen Labs, La Marque, TX 77568 USA. Tampa Gen Hosp, Tampa, FL 33601 USA. RP Crucian, B (reprint author), NASA, Lyndon B Johnson Space Ctr, Wyle Labs, 1290 Hercules Dr, Houston, TX 77058 USA. EM bcrucian@ems.jsc.nasa.gov; pascal.lee@marsinstitute.info; rpstowe@microgenlabs.com; jeffrey.a.jones@nasa.gov; rainer.k.effenhauser@nasa.gov; rwiden@tgh.org; csams@ems.jsc.nasa.gov NR 55 TC 11 Z9 11 U1 7 U2 13 PU BIOMED CENTRAL LTD PI LONDON PA MIDDLESEX HOUSE, 34-42 CLEVELAND ST, LONDON W1T 4LB, ENGLAND SN 1471-2172 J9 BMC IMMUNOL JI BMC Immunol. PD MAY 23 PY 2007 VL 8 AR 7 DI 10.1186/1471-2172-8-7 PG 13 WC Immunology SC Immunology GA 178IO UT WOS:000247214600001 PM 17521440 ER PT J AU Fleming, EL Jackman, CH Weisenstein, DK Ko, MKW AF Fleming, Eric L. Jackman, Charles H. Weisenstein, Debra K. Ko, Malcolm K. W. TI The impact of interannual variability on multidecadal total ozone simulations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review ID QUASI-BIENNIAL OSCILLATION; TROPICAL LOWER STRATOSPHERE; ZONALLY AVERAGED TRANSPORT; TWO-DIMENSIONAL MODEL; SOLAR PROTON EVENTS; 2-DIMENSIONAL MODEL; MIDDLE ATMOSPHERE; NORTHERN MIDLATITUDES; GENERAL-CIRCULATION; COLUMN OZONE AB [1] We have used a two-dimensional chemistry and transport model to study the effects of interannual dynamical variability on global total ozone for 1979-2004. Long-term meteorological data from the National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) reanalysis-2 project and the European Center for Medium Range Weather Forecasts (ECMWF) updated reanalysis (ERA-40) are used to construct yearly dynamical fields for use in the model. The simulations qualitatively resolve much of the seasonal and interannual variability observed in long-term global total ozone data, including fluctuations related to the quasi-biennial oscillation (QBO). We performed a series of model experiments to examine the relative roles of the interannual variability, changes in halogen and volcanic aerosol loading, and the 11-year solar cycle in controlling the multidecadal ozone changes. Statistical regression is used to isolate these signals in the observed and simulated time series. At Northern midlatitudes, the simulated interannual dynamical variability acts to reinforce the chemical ozone depletion caused by the enhanced aerosol loading following the eruption of Mt. Pinatubo in 1991. However, at Southern midlatitudes, the interannual variability masks the aerosol-induced chemical effect. The simulated solar cycle response in total ozone is generally consistent with observations and is primarily due to the direct photochemical effect. The halogen-induced total ozone trend for 1979-1996 derived from the model is in good agreement with that derived from observations in the tropics and the Northern Hemisphere (NH). However, at Southern midlatitudes, the trend derived from the model is more sensitive to halogen loading than that derived from observations. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. Atmospher & Environm Res Inc, Lexington, MA 02421 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Fleming, EL (reprint author), NASA, Goddard Space Flight Ctr, Code 613-3,Greenbelt Rd, Greenbelt, MD 20771 USA. EM fleming@kahuna.gsfc.nasa.gov; charles.h.jackman@nasa.gov; weisenstein@aer.com; malcolm.k.ko@nasa.gov RI Jackman, Charles/D-4699-2012; Ko, Malcolm/D-5898-2015 NR 104 TC 26 Z9 26 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 23 PY 2007 VL 112 IS D10 AR D10310 DI 10.1029/2006JD007953 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 173AR UT WOS:000246846400006 ER PT J AU Bousserez, N Attie, JL Peuch, VH Michou, M Pfister, G Edwards, D Emmons, L Mari, C Barret, B Arnold, SR Heckel, A Richter, A Schlager, H Lewis, A Avery, M Sachse, G Browell, EV Hair, JW AF Bousserez, N. Attie, J. L. Peuch, V. H. Michou, M. Pfister, G. Edwards, D. Emmons, L. Mari, C. Barret, B. Arnold, S. R. Heckel, A. Richter, A. Schlager, H. Lewis, A. Avery, M. Sachse, G. Browell, E. V. Hair, J. W. TI Evaluation of the MOCAGE chemistry transport model during the ICARTT/ITOP experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID DRY DEPOSITION VELOCITIES; MOZAIC AIRBORNE PROGRAM; IN-SERVICE AIRCRAFT; TROPOSPHERIC OZONE; GLOBAL SIMULATION; MOPITT INSTRUMENT; AIR-POLLUTION; WATER-VAPOR; ASIAN DUST; ART. AB [1] Intercontinental Transport of Ozone and Precursors (ITOP), part of International Consortium for Atmospheric Research on Transport and Transformation (ICARTT), was a large experimental campaign designed to improve our understanding of the chemical transformations within plumes during long-range transport (LRT) of pollution from North America to Europe. This campaign took place in July and August 2004, when a strong fire season occurred in North America. Burning by-products were transported over large distances, sometimes reaching Europe. A chemical transport model, Modelisation de la Chimie Atmospherique Grande Echelle (MOCAGE), with a high grid resolution (0.5 degrees x 0.5 degrees) over the North Atlantic area and a daily inventory of biomass burning emissions over the United States, has been used to simulate the period. By comparing our results with available aircraft in situ measurements and satellite data (MOPITT CO and SCIAMACHY NO2), we show that MOCAGE is capable of representing the main characteristics of the tropospheric ozone-NOx-hydrocarbon chemistry during the ITOP experiment. In particular, high resolution allows the accurate representation of the pathway of exported pollution over the Atlantic, where plumes were transported preferentially at 6 km altitude. The model overestimates OH mixing ratios up to a factor of 2 in the lower troposphere, which results in a global overestimation of hydrocarbons oxidation by-products ( PAN and ketones) and an excess of O-3 ( 30 - 50 ppbv) in the planetary boundary layer (PBL) over the continental United States. Sensitivity study revealed that lightning NO emissions contributed significantly to the NOx budget in the upper troposphere of northeast America during the summer 2004. C1 Univ Toulouse 3, OMP, Lab Aerol, F-31400 Toulouse, France. Meteo France, Ctr Natl Rech Meteorol, F-31057 Toulouse, France. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ Leeds, Sch Earth & Environm, Inst Atmospher Sci, Leeds LS2 9JT, W Yorkshire, England. Inst Environm Phys, D-28334 Bremen, Germany. Deutsch Zentrum Luft & Raumfahrt, Inst Phys Atmosphare, D-82230 Operpfaffenhofen, Wessling, Germany. Univ York, Dept Chem, York YO10 5DD, N Yorkshire, England. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Bousserez, N (reprint author), Univ Toulouse 3, OMP, Lab Aerol, 14 Ave Edouard Belin, F-31400 Toulouse, France. EM attjl@aero.obs-mip.fr RI Lewis, Alastair/A-6721-2008; Peuch, Vincent-Henri/A-7308-2008; Pfister, Gabriele/A-9349-2008; Richter, Andreas/C-4971-2008; Barret, Brice/I-9350-2012; Arnold, Steve/B-8856-2014; Emmons, Louisa/R-8922-2016; OI Lewis, Alastair/0000-0002-4075-3651; Richter, Andreas/0000-0003-3339-212X; Barret, Brice/0000-0002-1784-4758; Emmons, Louisa/0000-0003-2325-6212; Arnold, Steve/0000-0002-4881-5685 NR 63 TC 43 Z9 43 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 22 PY 2007 VL 112 IS D10 AR D10S42 DI 10.1029/2006JD007595 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 173AQ UT WOS:000246846300003 ER PT J AU Tang, SM Zhang, SN Hopkins, PF AF Tang, Su Min Zhang, Shuang Nan Hopkins, Philip F. TI Is the dependence of spectral index on luminosity real in optically selected AGN samples ? SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE methods : statistical; galaxies : active; quasars : general; X-rays : galaxies ID SOFT-X-RAY; ACTIVE GALACTIC NUCLEI; DIGITAL-SKY-SURVEY; COSMOLOGICAL EVOLUTION; ENERGY-DISTRIBUTION; QUASAR SURVEY; RADIO-QUIET; CHANDRA; EMISSION; REGRESSION AB We critically examine the dependence of spectral index on luminosity in optically selected AGN samples. An analysis of optically selected high-z quasars showed an anticorrelation of alpha(OX), the spectral index between the rest-frame 2500 angstrom and 2 keV, with optical luminosity. We examine this relationship by means of Monte Carlo simulations and conclude that a constant alpha(OX) independent of optical luminosity is still consistent with this high-z sample. We further find that contributions of large dispersions and narrow range of optical luminosity are most important for the apparent, yet artificial, alpha(OX)-l(o) correlation reported. We also examine another, but more complete, low-z optical selected AGN sub-sample from Steffen et al., and our analysis shows that a constant alpha(OX) independent of optical luminosity is also consistent with the data. By comparing X-ray and optical luminosity functions, we find that a luminosity-independent alpha(OX) is in fact more preferred than the luminosity-dependent alpha(OX) model. We also discuss the selection effects caused by flux limits, which might systematically bias the l(X)-l(o) relation and cause discrepancy in optically selected and X-ray selected AGN samples. To correctly establish a dependence of alpha(OX) of AGNs on their luminosity, a larger and more complete sample is needed and consequences of luminosity dispersions and selection effects in flux-limited samples must be taken into account properly. C1 Tsinghua Univ, Dept Phys, Beijing 100084, Peoples R China. Tsinghua Univ, Ctr Astrophys, Beijing 100084, Peoples R China. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Tang, SM (reprint author), Tsinghua Univ, Dept Phys, Beijing 100084, Peoples R China. EM stang@cfa.harvard.edu; zhangsn@tsinghua.edu.cn NR 33 TC 14 Z9 14 U1 0 U2 1 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 21 PY 2007 VL 377 IS 3 BP 1113 EP 1121 DI 10.1111/j.1365-2966.2007.11589.x PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 166GS UT WOS:000246367000013 ER PT J AU Zhang, PB Lee, C Verweij, H Akbar, SA Hunter, G Dutta, PK AF Zhang, Pengbei Lee, Chonghoon Verweij, Henk Akbar, Sheikh A. Hunter, Gary Dutta, Prabir K. TI High temperature sensor array for simultaneous determination of O-2, CO, and CO2 with kernel ridge regression data analysis SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article DE exhaust analysis; combustion sensors; harsh environment; fire safety ID CARBON-MONOXIDE; GAS SENSOR; ELECTROLYTE AB A sensor array comprising of three chemical gas sensors was evaluated to predict the concentrations of O-2 CO, and CO2 in a gas stream with the sensors at 600 degrees C. The data analysis involved a non-linear multivariate regression method (kernel ridge regression, KRR) along with a searching algorithm to predict gas concentrations. The sensors in the array included a resistance-based 2% CuO/10% La-2 O-3/TiO2 sensor, and two potentiometric sensors, including a yttria stabilized zirconia (YSZ) sensor with a metal/metal oxide internal reference electrode, and a lithium phosphate-based sensor. In addition, the possibility of using the KRR algorithm to predict gas concentrations beyond the training data is explored. (C) 2006 Elsevier B.V. All rights reserved. C1 Ohio State Univ, Dept Chem, Columbus, OH 43210 USA. Ohio State Univ, Dept Elect & Comp Engn, Columbus, OH 43210 USA. Ohio State Univ, Dept Mat Sci & Engn, Columbus, OH 43210 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Dutta, PK (reprint author), Ohio State Univ, Dept Chem, Columbus, OH 43210 USA. EM dutta.1@osu.edu RI Akbar, Sheikh/J-6170-2013; Verweij, Henk Verweij/F-6948-2015 OI Akbar, Sheikh/0000-0003-3567-274X; NR 21 TC 14 Z9 14 U1 1 U2 12 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD MAY 21 PY 2007 VL 123 IS 2 BP 950 EP 963 DI 10.1016/j.snb.2006.11.009 PG 14 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 176CJ UT WOS:000247060100044 ER PT J AU Raj, SV Barrett, C Karthikeyan, J Garlick, R AF Raj, S. V. Barrett, C. Karthikeyan, J. Garlick, R. TI Comparison of the cyclic oxidation behavior of cold sprayed CuCrAl-coated and uncoated GRCop-84 substrates for space launch vehicles SO SURFACE & COATINGS TECHNOLOGY LA English DT Article DE cold spray; GRCop-84; NiCrAlY coating; copper alloy coating; launch vehicles; oxidation AB A newly developed Cu-23 (wt.%) Cr-5% Al (CuCrAl) alloy shown to resist hydridation and oxidation in an as-cast form is currently being considered as a protective coating for GRCop-84, which is an advanced copper alloy containing 8 (at.%) Cr and 4 (at.%) Nb. The coating was deposited on GRCop-84 substrates by the cold spray deposition technique. Cyclic oxidation tests conducted in air on both coated and uncoated substrates between 773 and 1073 K revealed that the coating remained intact and protected the substrate up to 1073 K. No significant weight loss of the coated specimens were observed at 773 and 873 K after cumulative cyclic times of 500 and 250 h, respectively. About a 10% weight loss observed at 973 and 1073 K was attributed to the excessive oxidation of the uncoated sides. In contrast, the uncoated substrate lost as much as 80% of its original weight under similar test conditions. It is concluded that the cold sprayed CuCrAl coating is suitable for protecting GRCop-84 substrates. (C) 2007 Elsevier B.V. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. ASB Ind Inc, Barberton, OH 44203 USA. RP Raj, SV (reprint author), NASA, Glenn Res Ctr, MS 106-5,21000 Brookpk Rd, Cleveland, OH 44135 USA. EM sai.v.raj@nasa.gov NR 24 TC 10 Z9 14 U1 1 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD MAY 21 PY 2007 VL 201 IS 16-17 BP 7222 EP 7234 DI 10.1016/j.surfcoat.2007.01.034 PG 13 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 168FX UT WOS:000246509800044 ER PT J AU Papadakis, IE Ioannou, Z Kazanas, D AF Papadakis, I. E. Ioannou, Z. Kazanas, D. TI Fourier-resolved spectroscopy of active galactic nuclei using XMM-Newton data. I. The 3-10 keV band results SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : Seyfert; X-rays : galaxies ID ACCRETING BLACK-HOLES; X-RAY VARIABILITY; K-ALPHA LINE; SEYFERT-1 GALAXIES; SPECTRAL VARIABILITY; LUMINOUS LMXBS; BOUNDARY-LAYER; EMISSION; MCG-6-30-15; STATE AB We present the results from Fourier-resolved spectroscopy of archival XMM-Newton data of five AGNs, namely, Mrk 766, NGC 3516, NGC 3783, NGC 4051, and Ark 564. This work supplements an earlier study of MCG -6-30-15 and of several Galactic black hole candidate sources. Our results exhibit much larger diversity than for Galactic sources, a fact we attribute to the diversity of their masses. When we take into account this effect and combine our results with those for Cyg X-1, it seems reasonable to conclude that at high frequencies, the slope of the Fourier-resolved spectra in accreting black hole systems decreases with increasing frequency as proportional to f (-0.25), irrespective of whether the systemis in its high or low state. This result implies that the flux variations in AGNs are accompanied by complex spectral slope variations as well. We also find that the Fe K alpha line in Mrk 766, NGC 3783, and NGC 4051 is variable on timescales of similar to 1 day to 1 hr. The iron fluorescence line is absent in the spectra of the highest frequencies, and there is an indication that, just like in Cyg X-1, the equivalent width of the line in the Fourier-resolved AGNs decreases with increasing frequency. C1 Univ Crete, Dept Phys, Iraklion 71003, Crete, Greece. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Fdn Res & Technol Hellas, IESL, Iraklion 71110, Greece. RP Papadakis, IE (reprint author), Univ Crete, Dept Phys, Iraklion 71003, Crete, Greece. RI Papadakis, Iossif/C-3235-2011 NR 38 TC 10 Z9 10 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2007 VL 661 IS 1 BP 38 EP 51 DI 10.1086/513307 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169EE UT WOS:000246574700005 ER PT J AU Walter, F Cannon, JM Roussel, H Bendo, GJ Calzetti, D Dale, DA Draine, BT Helou, G Kennicutt, RC Moustakas, J Rieke, GH Armus, L Engelbracht, CW Gordon, K Hollenbach, DJ Lee, J Li, A Meyer, MJ Murphy, EJ Regan, MW Smith, JDT Brinks, E de Blok, WJG Bigiel, F Thornley, MD AF Walter, Fabian Cannon, John M. Roussel, Helene Bendo, George J. Calzetti, Daniela Dale, Daniel A. Draine, Bruce T. Helou, George Kennicutt, Robert C., Jr. Moustakas, John Rieke, George H. Armus, Lee Engelbracht, Charles W. Gordon, Karl Hollenbach, David J. Lee, Janice Li, Aigen Meyer, Martin J. Murphy, Eric J. Regan, Michael W. Smith, John-David T. Brinks, Elias de Blok, W. J. G. Bigiel, Frank Thornley, Michele D. TI Dust and atomic gas in dwarf irregular galaxies of the M81 group: The SINGS and things view SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : dwarf; galaxies : individual ( DDO 53, DDO 165, Holmberg I; Holmberg II, IC 2574, M81 dwA, M81 dwB); galaxies : irregular; galaxies : ISM; infrared : galaxies ID AROMATIC-HYDROCARBON EMISSION; SPECTRAL ENERGY-DISTRIBUTION; STAR-FORMING GALAXIES; ELEMENTAL ABUNDANCE VARIATIONS; LOW-METALLICITY ENVIRONMENTS; INFRARED-EMISSION; INTERSTELLAR-MEDIUM; GLOBAL PROPERTIES; NEARBY GALAXIES; MASSIVE STARS AB We present observations of the dust and atomic gas phase in seven dwarf irregular galaxies of the M81 group from the Spitzer SINGS and VLA THINGS surveys. The Spitzer observations provide a first glimpse of the nature of the nonatomic ISM in these metal-poor (Z similar to 0.1 Z(circle dot)), quiescent (SFR similar to 0.001-0.1 M-circle dot yr(-1)) dwarf galaxies. Most detected dust emission is restricted to H I column densities > 1x 10(21) cm(-2), and almost all regions of high H I column density (> 2.5 x 10(21) cm(-2)) have associated dust emission. Spitzer spectroscopy of two regions in the brightest galaxies (IC 2574 and Holmberg II) show distinctly different spectral shapes and aromatic features, although the galaxies have comparable gas-phase metallicities. This result emphasizes that the strength of the aromatic features is not a simple linear function of metallicity. We estimate dust masses of similar to 10(4-)10(6) M-circle dot for the M81 dwarf galaxies, resulting in an average dust-to-gas ratio (M-dust/M-H (I)) of similar to 3 x 10(-4) (1.5 x 10(-3) if only the H I that is associated with dust emission is considered); this is an order of magnitude lower than the typical value derived for the SINGS spirals. The dwarf galaxies are underluminous per unit star formation rate at 70 mu m as compared to the more massive galaxies in SINGS by a factor of similar to 2. However, the average 70/160 mu m ratio in the sample dwarf galaxies is higher than what is found in the other galaxies of the SINGS sample. This can be explained by a combination of a lower dust content in conjunction with a higher dust temperature in the dwarfs. C1 Max Planck Inst Astron, D-69117 Heidelberg, Germany. Wesleyan Univ, Dept Astron, Middletown, CT 06459 USA. Univ London Imperial Coll Sci Technol & Med, London SW7 2AZ, England. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. CALTECH, Pasadena, CA 91101 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NYU, Dept Phys, New York, NY 10003 USA. Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA. Yale Univ, Dept Astron, New Haven, CT 06520 USA. Univ Hertfordshire, Ctr Astrophys Res, Hatfield AL10 9AB, Herts, England. Mt Stromlo & Siding Spring Observ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia. Bucknell Univ, Dept Phys, Lewisburg, PA 17837 USA. RP Cannon, JM (reprint author), Max Planck Inst Astron, D-69117 Heidelberg, Germany. OI Draine, Bruce/0000-0002-0846-936X; Brinks, Elias/0000-0002-7758-9699 NR 61 TC 70 Z9 71 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2007 VL 661 IS 1 BP 102 EP 114 DI 10.1086/514807 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169EE UT WOS:000246574700012 ER PT J AU de Paz, AG Madore, BF Boissier, S Thilker, D Bianchi, L Contreras, CS Barlow, TA Conrow, T Forster, K Friedman, PG Martin, DC Morrissey, P Neff, SG Rich, RM Schiminovich, D Seibert, M Small, T Donas, J Heckman, TM Lee, YW Milliard, B Szalay, AS Wyder, TK Yi, S AF de Paz, Armando Gil Madore, Barry F. Boissier, Samuel Thilker, David Bianchi, Luciana Contreras, Carmen Sanchez Barlow, Tom A. Conrow, Tim Forster, Karl Friedman, Peter G. Martin, D. Christopher Morrissey, Patrick Neff, Susan G. Rich, R. Michael Schiminovich, David Seibert, Mark Small, Todd Donas, Jose Heckman, Timothy M. Lee, Young-Wook Milliard, Bruno Szalay, Alex S. Wyder, Ted K. Yi, Sukyoung TI Chemical and photometric evolution of extended ultraviolet disks: Optical spectroscopy of M83 ( NGC 5236) and NGC 4625 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : abundances; galaxies : evolution; H ii regions; techniques : spectroscopic; ultraviolet : galaxies ID H-II REGIONS; CHEMO-SPECTROPHOTOMETRIC EVOLUTION; EMISSION-LINE GALAXIES; STAR-FORMATION RATE; OXYGEN ABUNDANCE DETERMINATION; COMBINED STELLAR STRUCTURE; DE-MADRID LIST; SPIRAL GALAXIES; INFRARED-EMISSION; GALACTIC DISKS AB We present the results from the analysis of optical spectra of 31 H alpha-selected regions in the extended UV (XUV) disks of M83 (NGC 5236) and NGC 4625 recently discovered by GALEX. The spectra were obtained using IMACS at the Las Campanas Observatory 6.5 m Magellan I telescope and COSMIC at the Palomar 200 inch (5 m) telescope, respectively, for M83 and NGC 4625. The line ratios measured indicate nebular oxygen abundances (derived from the R23 parameter) of the order of Z(circle dot)/5-Z(circle dot)/10. For most emission-line regions analyzed the line fluxes and ratios measured are best reproduced by models of photoionization by single stars with masses in the range 20-40 M-circle dot and oxygen abundances comparable to those derived from the R23 parameter. We find indications for a relatively high N/O abundance ratio in the XUV disk of M83. Although the metallicities derived imply that these are not the first stars formed in the XUV disks, such a level of enrichment could be reached in young spiral disks only 1 Gyr after these first stars would have formed. The amount of gas in the XUV disks allows maintaining the current level of star formation for at least a few Gyr. C1 Observ Carnegie Inst Washington, The Observ, Pasadena, CA 91101 USA. Univ Complutense Madrid, Dept Astrofis, E-28040 Madrid, Spain. CALTECH, NASA, IPAC Extragalact Database, Pasadena, CA 91125 USA. Astrophys Lab, F-13376 Marseille 12, France. Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA. CSIC, Ctr Estudios Mat, Madrid 29006, Spain. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Yonsei Univ, Ctr Space Astrophys, Seoul 120749, South Korea. RP de Paz, AG (reprint author), Observ Carnegie Inst Washington, The Observ, Pasadena, CA 91101 USA. EM agpaz@ociw.edu; barry@ipac.caltech.edu; samuel.boissier@oamp.fr; dthilker@pha.jhu.edu; bianchi@pha.jhu.edu; carmen@damir.iem.csic.es; tab@srl.caltech.edu; tim@srl.caltech.edu; krl@srl.caltech.edu; friedman@srl.caltech.edu; cmartin@srl.caltech.edu; patrick@srl.caltech.edu; neff@stars.gsfc.nasa.gov; rmr@astro.ucla.edu; ds@srl.caltech.edu; mseibert@srl.caltech.edu; tas@srl.caltech.edu; jose.donas@oamp.fr; heckman@pha.jhu.edu; ywlee@csa.yonsei.ac.kr; bruno.milliard@oamp.fr; szalay@pha.jhu.edu; wyder@srl.caltech.edu; yi@astro.ox.ac.uk RI Gil de Paz, Armando/J-2874-2016 OI Gil de Paz, Armando/0000-0001-6150-2854 NR 86 TC 49 Z9 49 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2007 VL 661 IS 1 BP 115 EP 134 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169EE UT WOS:000246574700013 ER PT J AU Henley, DB Shelton, RL Kuntz, KD AF Henley, David B. Shelton, Robin L. Kuntz, K. D. TI An XMM-Newton observation of the local bubble using a shadowing filament in the southern galactic hemisphere SO ASTROPHYSICAL JOURNAL LA English DT Article DE Galaxy : general; Galaxy : halo; ISM : general; ISM : individual (Local Bubble); X-rays : ISM ID SOFT-X-RAY; INTERSTELLAR-MEDIUM; CROSS-SECTIONS; ABSORPTION; SOLAR; GAS; EMISSION; ELEMENTS; MODELS; HALO AB We present an analysis of the X-ray spectrum of the Local Bubble, obtained by simultaneously analyzing spectra from two XMM-Newton pointings on and off an absorbing filament in the southern Galactic hemisphere (b approximate to - 45 degrees). We use the difference in the Galactic column density in these two directions to deduce the contributions of the unabsorbed foreground emission due to the Local Bubble, and the absorbed emission from the Galactic halo and the extragalactic background. We find the Local Bubble emission is consistent with emission from a plasma in collisional ionization equilibrium with a temperature log (TLB/K) = 6.06(-0.04)(+0.02) and an emission measure integral n(e)(2)dl = 0.018 cm(-6) pc. Our measured temperature is in good agreement with values obtained from ROSAT All-Sky Survey data, but is lower than that measured by other recent XMM-Newton observations of the Local Bubble, which find log (T-LB/K) approximate to 6.2 (although for some of these observations it is possible that the foreground emission is contaminated by non-Local Bubble emission from Loop I). The higher temperature observed toward other directions is inconsistent with our data when combined with a FUSE measurement of the Galactic halo O VI intensity. This therefore suggests that the Local Bubble is thermally anisotropic. Our data are unable to rule out a nonequilibrium model in which the plasma is underionized. However, an overionized recombining plasma model, while observationally acceptable for certain densities and temperatures, generally gives an implausibly young age for the Local Bubble (less than or similar to 6 x 10(5) yr). C1 Univ Georgia, Dept Phys & Astron, Athens, GA 30602 USA. Johns Hopkins Univ, Henry A Rowland Dept Phys & Astron, Baltimore, MD 21218 USA. NASA Goddard Space Flight Ctr, Explorat Univere Div, Greenbelt, MD 20771 USA. RP Henley, DB (reprint author), Univ Georgia, Dept Phys & Astron, Athens, GA 30602 USA. EM dbh@physast.uga.edu; rls@hal.physast.uga.edu; kuntz@milkyway.gsfc.nasa.gov NR 68 TC 33 Z9 34 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2007 VL 661 IS 1 BP 304 EP 319 DI 10.1086/513590 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169EE UT WOS:000246574700027 ER PT J AU Wolff, CL O'Donovan, AE AF Wolff, Charles L. O'Donovan, Adam E. TI Coupled groups of g-modes in a Sun with a mixed core SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : oscillations; Sun : interior; Sun : oscillations ID SOLAR-NEUTRINO PROBLEM; ANGULAR-MOMENTUM; CONVECTION ZONE; INTERNAL WAVES; STABILITY; TRANSPORT; INTERIOR; HELIOSEISMOLOGY; OSCILLATIONS; FREQUENCIES AB Groups of linear g-modes can sum to create nonlinear motion in small '' hot volumes '' ( diameter similar to 10 Mm) near the solar center that help drive the modes. We explore the consequences of coupling only in the hot volumes where the time-averaged rate of (3)He burning can double if temperature oscillations exceed 10%. Anticipating large local motions in the core, we impose a mixed shell r = ( 0: 10 +/- 0: 03) R circle dot on an otherwise standard solar model before computing g-mode solutions. Mixing is rapid (<<10(6) yr) in this shell, with slower mixing somewhat beyond. If l is the principal spherical harmonic index, a set of g-modes for any single l similar to 5 with six consecutive radial harmonics can be excited with nearly linear thermal amplitudes AT <= 0: 05 throughout the star. But far smaller thresholds for excitation are actually expected when sets for many values of l can be computed simultaneously. This is a new kind of stellar instability whose effectiveness rises with the number of active modes. Each set rotates rigidly and maximizes the release of nuclear energy from its hot volumes. There is some evidence for their rotation rates in the long solar activity record. The upward wave flux powered by the hot volumes has also been suggested to explain the 1.3 yr reversing flows tentatively detected below the Sun's convective envelope. An analog using uncoupled modes is also investigated based on an observation that indicates g-mode activity up to l empty set 20. If all modes in that range had linear amplitudes of only ATempty set 0: 0015, their combined effect would give positive growth rates to dozens of low harmonic g-modes. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, College Pk, MD 20742 USA. RP Wolff, CL (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM charles.l.wolff@nasa.gov OI Wolff, Charles/0000-0001-8854-507X NR 49 TC 10 Z9 10 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2007 VL 661 IS 1 BP 568 EP 585 DI 10.1086/513305 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169EE UT WOS:000246574700053 ER PT J AU Hajian, AR Behr, BB Cenko, AT Olling, RP Mozurkewich, D Armstrong, JT Pohl, B Petrossian, S Knuth, KH Hindsley, RB Murison, M Efroimsky, M Dantowitz, R Kozubal, M Currie, DG Nordgren, TE Tycner, C McMillan, RS AF Hajian, Arsen R. Behr, Bradford B. Cenko, Andrew T. Olling, Robert P. Mozurkewich, David Armstrong, J. Thomas Pohl, Brian Petrossian, Sevan Knuth, Kevin H. Hindsley, Robert B. Murison, Marc Efroimsky, Michael Dantowitz, Ronald Kozubal, Marek Currie, Douglas G. Nordgren, Tyler E. Tycner, Christopher McMillan, Robert S. TI Initial results from the usno dispersed Fourier transform spectrograph SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : spectroscopic; instrumentation : interferometers; instrumentation : spectrographs; planetary systems; techniques : interferometric ID STELLAR SPECTRA; SPACED DATA; CONSTRAINTS; PARAMETERS; PRECISION; CATALOG; LINES AB We have designed and constructed a '' dispersed Fourier transform spectrometer '' (dFTS), consisting of a conventional FTS followed by a grating spectrometer. By combining these two devices, we negate a substantial fraction of the sensitivity disadvantage of a conventional FTS for high-resolution, broadband, optical spectroscopy, while preserving many of the advantages inherent to interferometric spectrometers. In addition, we have implemented a simple and inexpensive laser metrology system, which enables very precise calibration of the interferometer wavelength scale. The fusion of interferometric and dispersive technologies with a laser metrology system yields an instrument well suited to stellar spectroscopy, velocimetry, and extrasolar planet detection, which is competitive with existing high- resolution, high- accuracy stellar spectrometers. In this paper we describe the design of our prototype dFTS, explain the algorithm we use to efficiently reconstruct a broadband spectrum from a sequence of narrowband interferograms, and present initial observations and resulting velocimetry of stellar targets. C1 USN Observ, Washington, DC 20392 USA. USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Seabrook Engn, Lanham, MD 20706 USA. Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. NVI Inc, Greenbelt, MD 20770 USA. NASA, Ames Res Ctr, Intelligent Syst Div, Moffett Field, CA 94035 USA. Dexter & Southfield Sch, Clay Ctr Observ, Brookline, MA 02445 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. USN Observ, Flagstaff, AZ 86001 USA. Univ Redlands, Dept Phys, Redlands, CA 92373 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RP Hajian, AR (reprint author), USN Observ, Washington, DC 20392 USA. EM hajian@usno.navy.mil; bbb@usno.navy.mil; atc@usno.navy.mil; olling@astro.umd.edu; dave@mozurkewich.com; tom.armstrong@nrl.navy.mil; bpohl@physics.unc.edu; spetrossian@excelgov.org; kknuth@albany.edu; hindsley@nrl.navy.mil; murison@usno.navy.mil; me@usno.navy.mil; dantowitz@dexter.org; marek@portents.com; currie@umd.edu; tyler_nordgren@redlands.edu; tycner@nofs.navy.mil; bob@lpl.arizona.edu OI Efroimsky, Michael/0000-0003-1249-9622 NR 34 TC 9 Z9 9 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2007 VL 661 IS 1 BP 616 EP 633 DI 10.1086/513181 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169EE UT WOS:000246574700057 ER PT J AU Bonev, BP Mumma, MJ Villanueva, GL Disanti, MA Ellis, RS Magee-Sauer, K Dello Russo, N AF Bonev, Boncho P. Mumma, Michael J. Villanueva, Geronimo L. Disanti, Michael A. Ellis, Richard S. Magee-Sauer, Karen Dello Russo, Neil TI A search for variation in the H2O ortho-para ratio and rotational temperature in the inner coma of comet C/2004 Q2 (Machholz) SO ASTROPHYSICAL JOURNAL LA English DT Article DE comets : general; comets : individual (C/2004 Q2 (Machholz)); infrared : solar system ID NUCLEAR-SPIN CONVERSION; WATER PRODUCTION; HYDROGEN; SEPARATION; MOLECULES; EMISSION; ISOMERS; METHANE; NEAT; LEE AB We present spatially resolved measurements of the rotational temperature and ortho-para ratio for H2O in the inner coma of the Oort Cloud comet C/2004 Q2 ( Machholz). Our results are based on direct simultaneous detections of ortho-H2O and para-H2O via" hot-band" fluorescence near 2.9 mu m. We find a well-defined decline in rotational temperature with increasing nucleocentric distance ( up to similar to 1000 km). The ortho-para ratio remains constant ( within stochastic uncertainty) with increasing nucleocentric distance and is close to the statistical equilibrium value of 3.0 (2.86 +/- 0.06 [ 0.17], including, respectively, stochastic [ systematic] uncertainty), resulting 00in spin temperature T-spin >= 34 K. We compare the present results with those reported for other comets and discuss the difficulties in interpreting spin temperatures deduced from measured ortho-para ratios. Improved understanding of the special conditions that enable nuclear spin conversion would test the extent to which derived spin temperatures reflect the formative history or the processing record of cometary ices. C1 Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. Univ Toledo, Toledo, OH 43606 USA. NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Greenbelt, MD 20771 USA. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Rowan Univ, Dept Phys & Astron, Glassboro, NJ 08028 USA. Johns Hopkins Univ, Appl Phys Lab, Dept Space, Planetary Explorat Grp, Laurel, MD 20023 USA. RP Bonev, BP (reprint author), Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. EM bbonev@ssedmail.gsfc.nasa.gov RI mumma, michael/I-2764-2013; Magee-Sauer, Karen/K-6061-2015; Dello Russo, Neil/G-2727-2015 OI Magee-Sauer, Karen/0000-0002-4979-9875; Dello Russo, Neil/0000-0002-8379-7304 NR 23 TC 44 Z9 44 U1 1 U2 10 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2007 VL 661 IS 1 BP L97 EP L100 DI 10.1086/518419 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169EH UT WOS:000246575000025 ER PT J AU DiSanti, MA Anderson, WM Villanueva, GL Bonev, BP Magee-Sauer, K Gibb, EL Mumma, MJ AF DiSanti, M. A. Anderson, W. M. Villanueva, G. L. Bonev, B. P. Magee-Sauer, K. Gibb, E. L. Mumma, M. J. TI Depleted carbon monoxide in fragment C of the Jupiter-family comet 73P/Schwassmann-Wachmann 3 SO ASTROPHYSICAL JOURNAL LA English DT Article DE comets : general; comets : individual (73P/Schwassmann-Wachmann 3); molecular processes; solar system : formation ID DEEP-IMPACT; PARENT VOLATILES; COMET 73P/SCHWASSMANN-WACHMANN-3; 9P/TEMPEL-1; ENCOUNTER; EMISSION; METHANE; ORIGIN; WATER; DUST AB Carbon monoxide emission was targeted in fragment C of the recently split Jupiter-family comet 73P/Schwassmann-Wachmann 3 during its 2006 apparition, using the Cryogenic Echelle Spectrograph ( CSHELL) at the NASA IRTF on Mauna Kea, Hawaii. Simultaneous sounding with H2O near 4.65 mu m revealed highly depleted CO, consistent with a mixing ratio of 0.5% +/- 0.13%. Along with depleted CH3OH but nearly normal HCN, this may indicate that this comet formed in the inner giant planets' region or, alternatively, that it formed relatively late, after significant clearing of the protosolar nebula. C1 NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Greenbelt, MD 20771 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. Rowan Univ, Dept Phys & Astron, Glassboro, NJ 08028 USA. Univ Missouri, Dept Phys & Astron, St Louis, MO 63121 USA. RP DiSanti, MA (reprint author), NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Code 693, Greenbelt, MD 20771 USA. EM disanti@ssedmail.gsfc.nasa.gov RI mumma, michael/I-2764-2013; Magee-Sauer, Karen/K-6061-2015 OI Magee-Sauer, Karen/0000-0002-4979-9875 NR 45 TC 30 Z9 30 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2007 VL 661 IS 1 BP L101 EP L104 DI 10.1086/518716 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169EH UT WOS:000246575000026 ER PT J AU Xie, Y Qu, JJ Xiong, X Hao, X Che, N Sommers, W AF Xie, Y. Qu, J. J. Xiong, X. Hao, X. Che, N. Sommers, W. TI Smoke plume detection in the eastern United States using MODIS SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID RADIATION BUDGET; SATELLITE DATA; FIRE; IMAGERY; VALIDATION; ALGORITHM; AEROSOLS AB In the eastern United States large amounts of smoke emitted from both wildfires and prescribed fires affect the regional air quality and long-term climate and may have an impact on public health. Satellite remote sensing is an effective approach for detecting and monitoring the smoke plume. The spectral characteristics of smoke plume are measurably different from those of other cover types, such as vegetation, cloud, snow, and so on. A multi-threshold method has been developed for detecting smoke plumes with eight MODIS spectral bands based on the analysis of spectral characteristics of different cover types. A series of tests are applied to all pixels in one granule (5-min measurements) to filter out non-smoke pixels step by step with water masking. At each step, specific thresholds are utilized. The results have been validated with true color images for a number of cases from different areas and time, showing that the algorithm works well except for a few missing or incorrect identified smoke pixels. C1 George Mason Univ, CEOSR, EastFIRE Lab, Fairfax, VA 22030 USA. NASA, Goddard Space Flight Ctr, Biosphere Sci Branch, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP Xie, Y (reprint author), George Mason Univ, CEOSR, EastFIRE Lab, MS 5C3, Fairfax, VA 22030 USA. EM yxie2@gmu.edu RI Hao, Xianjun/F-7253-2016; Hao, Xianjun/C-9543-2011 OI Hao, Xianjun/0000-0002-8186-6839; Hao, Xianjun/0000-0002-8186-6839 NR 17 TC 4 Z9 5 U1 2 U2 6 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND SN 0143-1161 EI 1366-5901 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD MAY 20 PY 2007 VL 28 IS 10 BP 2367 EP 2374 DI 10.1080/01431160701236795 PG 8 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 180OY UT WOS:000247376600020 ER PT J AU Swanson, RC Turkel, E Rossow, CC AF Swanson, R. C. Turkel, E. Rossow, C.-C. TI Convergence acceleration of Runge-Kutta schemes for solving the Navier-Stokes equations SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE Navier-Stokes; Runge-Kutta; implicit preconditioning; fourier analysis; multigrid ID INCOMPRESSIBLE FLOWS; DIFFERENCE; SOLVERS; MESHES AB The convergence of a Runge-Kutta (RK) scheme with multigrid is accelerated by preconditioning with a fully implicit operator. With the extended stability of the Runge-Kutta scheme, CFL numbers as high as 1000 can be used. The implicit preconditioner addresses the stiffness in the discrete equations associated with stretched meshes. This RK/implicit scheme is used as a smoother for multigrid. Fourier analysis is applied to determine damping properties. Numerical dissipation operators based on the Roe scheme, a matrix dissipation, and the CUSP scheme are considered in evaluating the RK/implicit scheme. In addition, the effect of the number of RK stages is examined. Both the numerical and computational efficiency of the scheme with the different dissipation operators are discussed. The RK/implicit scheme is used to solve the two-dimensional (2-D) and three-dimensional (3-D) compressible, Reynolds-averaged Navier-Stokes equations. Turbulent flows over an airfoil and wing at subsonic and transonic conditions are computed. The effects of the cell aspect ratio on convergence are investigated for Reynolds numbers between 5.7 x 10(6) and 100 x 10(6). It is demonstrated that the implicit preconditioner can reduce the computational time of a well-tuned standard RK scheme by a factor between 4 and 10. (c) 2007 Elsevier Inc. All rights reserved. C1 NASA, Langley Res Ctr, Computat Aerosci Branch, Hampton, VA 23681 USA. Tel Aviv Univ, Dept Math, IL-69978 Tel Aviv, Israel. Deutsch Zentrum Luft & Raumfahrt, D-38108 Braunschweig, Germany. RP Swanson, RC (reprint author), NASA, Langley Res Ctr, Computat Aerosci Branch, Mail Stop 128, Hampton, VA 23681 USA. EM r.c.swanson@nasa.gov RI Turkel, Eli/F-6297-2011 OI Turkel, Eli/0000-0003-4273-0303 NR 36 TC 25 Z9 27 U1 1 U2 5 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY 20 PY 2007 VL 224 IS 1 BP 365 EP 388 DI 10.1016/j.jcp.2007.02.028 PG 24 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 179YD UT WOS:000247325600021 ER PT J AU Farr, TG Rosen, PA Caro, E Crippen, R Duren, R Hensley, S Kobrick, M Paller, M Rodriguez, E Roth, L Seal, D Shaffer, S Shimada, J Umland, J Werner, M Oskin, M Burbank, D Alsdorf, D AF Farr, Tom G. Rosen, Paul A. Caro, Edward Crippen, Robert Duren, Riley Hensley, Scott Kobrick, Michael Paller, Mimi Rodriguez, Ernesto Roth, Ladislav Seal, David Shaffer, Scott Shimada, Joanne Umland, Jeffrey Werner, Marian Oskin, Michael Burbank, Douglas Alsdorf, Douglas TI The shuttle radar topography mission SO REVIEWS OF GEOPHYSICS LA English DT Review ID SYNTHETIC-APERTURE RADAR; SRTM-C-BAND; DIGITAL ELEVATION MODELS; IMAGING RADAR; INTERFEROMETRIC RADAR; ROCK-UPLIFT; TIEN-SHAN; SATELLITE; HIMALAYAS; LANDSCAPE AB [1] The Shuttle Radar Topography Mission produced the most complete, highest-resolution digital elevation model of the Earth. The project was a joint endeavor of NASA, the National Geospatial-Intelligence Agency, and the German and Italian Space Agencies and flew in February 2000. It used dual radar antennas to acquire interferometric radar data, processed to digital topographic data at 1 arc sec resolution. Details of the development, flight operations, data processing, and products are provided for users of this revolutionary data set. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ N Carolina, Dept Geol Sci, Chapel Hill, NC 27599 USA. Deutsch Zentrum Luft & Raumfahrt, D-82230 Wessling, Germany. Ohio State Univ, Dept Geol Sci, Columbus, OH 43210 USA. Univ Calif Santa Barbara, Dept Earth Sci, Santa Barbara, CA 93106 USA. RP Farr, TG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM tom.farr@jpl.nasa.gov OI Farr, Thomas/0000-0001-5406-2096 NR 87 TC 1304 Z9 1329 U1 19 U2 161 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PD MAY 19 PY 2007 VL 45 IS 2 AR RG2004 DI 10.1029/2005RG000183 PG 33 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 172YT UT WOS:000246841400001 ER PT J AU Shim, CS Wang, YH Singh, HB Blake, DR Guenther, AB AF Shim, Changsub Wang, Yuhang Singh, Hanwant B. Blake, Donald R. Guenther, Alex B. TI Source characteristics of oxygenated volatile organic compounds and hydrogen cyanide SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PACIFIC EXPLORATORY MISSION; PEM-TROPICS-B; CARBON-MONOXIDE; ATMOSPHERIC OBSERVATIONS; CYANOGENIC GLYCOSIDES; GLOBAL-MODEL; TRACE GASES; ART.; EMISSIONS; METHANOL AB [1] Airborne trace gas measurements from Transport and Chemical Evolution over the Pacific (TRACE-P), Pacific Exploratory Mission (PEM)-Tropics B, and Intercontinental Chemical Transport Experiment-North America (INTEX-NA) experiments are analyzed to examine the major source factors contributing to the observed variabilities of oxygenated volatile organic compounds and cyanides. The positive matrix factorization method is applied to coincident measurements of 11 chemicals including CH3OH, CH3COCH3, CH3CHO, C2H2, C2H6, i-C5H12, CO, CH3Cl, and CHBr3. Measurements of HCN and CH3CN are available for TRACE-P and INTEX-NA. We identify major source contributions from the terrestrial biosphere, biomass burning, industry/urban regions, and oceans. Spatial and back trajectory characteristics of these factors are examined. On the basis of TRACE-P and PEM-Tropics B data, we find a factor that explains 80 - 88% of the CH3OH variability, 20 - 40% of CH3COCH3, 7 - 35% of CH3CHO, and 41% of HCN, most likely representing the emissions from terrestrial biosphere. Our analysis suggested that biogenic emissions of HCN may be significant. Cyanogenesis in plants is likely a major emission process for HCN, which was not fully accounted for previously. Larger contributions than previous global estimations to CH3COCH3 and CH3CHO by biomass burning and industry/urban sources likely reflect significant secondary production from volatile organic compound oxidation. No evidence was found for large emissions of CH3COCH3 from the ocean. The oceanic CH3CHO contribution implies large regional variations. C1 Georgia Inst Technol, Dept Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Shim, CS (reprint author), Georgia Inst Technol, Dept Earth & Atmospher Sci, Atlanta, GA 30332 USA. EM cshim@eas.gatech.edu RI Wang, Yuhang/B-5578-2014; Guenther, Alex/B-1617-2008 OI Guenther, Alex/0000-0001-6283-8288 NR 49 TC 20 Z9 20 U1 1 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 18 PY 2007 VL 112 IS D10 AR D10305 DI 10.1029/2006JD007543 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 172XV UT WOS:000246839000003 ER PT J AU Malin, MC Bell, JF Cantor, BA Caplinger, MA Calvin, WM Clancy, RT Edgett, KS Edwards, L Haberle, RM James, PB Lee, SW Ravine, MA Thomas, PC Wolff, MJ AF Malin, Michael C. Bell, James F., III Cantor, Bruce A. Caplinger, Michael A. Calvin, Wendy M. Clancy, R. Todd Edgett, Kenneth S. Edwards, Lawrence Haberle, Robert M. James, Philip B. Lee, Steven W. Ravine, Michael A. Thomas, Peter C. Wolff, Michael J. TI Context Camera Investigation on board the Mars Reconnaissance Orbiter SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Review ID RESOLUTION STEREO CAMERA; NORTH POLAR-REGION; CRATER EJECTA MORPHOLOGIES; LOBATE DEBRIS APRONS; SURFACE GROUND ICE; MARTIAN GULLIES; CERBERUS FOSSAE; VARIABLE FEATURES; CARBON-DIOXIDE; WIND STREAKS AB [1] The Context Camera (CTX) on the Mars Reconnaissance Orbiter (MRO) is a Facility Instrument (i.e., government-furnished equipment operated by a science team not responsible for design and fabrication) designed, built, and operated by Malin Space Science Systems and the MRO Mars Color Imager team (MARCI). CTX will ( 1) provide context images for data acquired by other MRO instruments, ( 2) observe features of interest to NASA's Mars Exploration Program ( e. g., candidate landing sites), and ( 3) conduct a scientific investigation, led by the MARCI team, of geologic, geomorphic, and meteorological processes on Mars. CTX consists of a digital electronics assembly; a 350 mm f/3.25 Schmidt-type telescope of catadioptric optical design with a 5.7 degrees field of view, providing a similar to 30-km-wide swath from similar to 290 km altitude; and a 5000-element CCD with a band pass of 500 - 700 nm and 7 mu m pixels, giving similar to 6 m/pixel spatial resolution from MRO's nearly circular, nearly polar mapping orbit. Raw data are transferred to the MRO spacecraft flight computer for processing ( e. g., data compression) before transmission to Earth. The ground data system and operations are based on 9 years of Mars Global Surveyor Mars Orbiter Camera on-orbit experience. CTX has been allocated 12% of the total MRO data return, or about >= 3 terabits for the nominal mission. This data volume would cover similar to 9% of Mars at 6 m/pixel, but overlapping images ( for stereo, mosaics, and observation of changes and meteorological events) will reduce this area. CTX acquired its first ( instrument checkout) images of Mars on 24 March 2006. C1 Malin Space Sci Syst, San Diego, CA 92191 USA. Space Sci Inst, Boulder, CO 80301 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Denver Museum Nat & Sci, Denver, CO 80205 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Univ Nevada, Dept Geol Sci, Reno, NV 89557 USA. RP Malin, MC (reprint author), Malin Space Sci Syst, POB 910148, San Diego, CA 92191 USA. OI Edgett, Kenneth/0000-0001-7197-5751 NR 196 TC 271 Z9 271 U1 4 U2 26 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 18 PY 2007 VL 112 IS E5 AR E05S04 DI 10.1029/2006JE002808 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 172YI UT WOS:000246840300002 ER PT J AU Seu, R Phillips, RJ Biccari, D Orosei, R Masdea, A Picardi, G Safaeinili, A Campbell, BA Plaut, JJ Marinangeli, L Smrekar, SE Nunes, DC AF Seu, Roberto Phillips, Roger J. Biccari, Daniela Orosei, Roberto Masdea, Arturo Picardi, Giovanni Safaeinili, Ali Campbell, Bruce A. Plaut, Jeffrey J. Marinangeli, Lucia Smrekar, Suzanne E. Nunes, Daniel C. TI SHARAD sounding radar on the Mars Reconnaissance Orbiter SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID TERRA-MERIDIANI; GROUND ICE; ART.; SUBSURFACE; LOWLANDS; SURFACE; ORIGIN AB [1] SHARAD (SHAllow RADar) is a sounding radar provided by Agenzia Spaziale Italiana (ASI) as a Facility Instrument on the Mars Reconnaissance Orbiter mission. Its 20-MHz center frequency and 10-MHz bandwidth complement the lower-frequency, relatively narrower bandwidth capability of the MARSIS sounding radar. A joint Italian-U.S. team has guided the experiment development and is responsible for data analysis and interpretation. The radar transmits signals at a 700 Hz pulse repetition frequency (PRF) and collects reflections from both the surface and near subsurface of Mars. Vertical and horizontal resolutions are, respectively, 15 m ( free-space) and 3 - 6 km (cross-track) by 0.3 - 1 km ( along- track). The scientific objective of SHARAD is to map, in selected locales, dielectric interfaces to at least several hundred meters depth in the Martian subsurface and to interpret these results in terms of the occurrence and distribution of expected materials, including competent rock, soil, water, and ice. A signal-to-noise ratio of similar to 50 dB ( for a specular surface return) is achieved with 10 W of radiated power by using range and azimuth focusing in ground data processing. Preprocessed data as well as range- and azimuth-focused data will be formatted according to Planetary Data System (PDS) standards and be made available from the ASI Science Data Center (ASDC) and from the Geosciences Node of the Planetary Data System ( PDS). Important targets for SHARAD include the polar layered deposits, sedimentary stacks ( especially in Terra Meridiani), buried channel systems, buried impact craters, volcanic complexes, and shallow ice deposits in equilibrium with the atmosphere. C1 Univ Roma La Sapienza, INFOCOM, I-00184 Rome, Italy. Smithsonian Inst, Ctr Earth & Planetary Studies, Washington, DC 20013 USA. Univ G DAnnunzio, IRSPS, I-65127 Pescara, Italy. Lunar & Planetary Inst, Houston, TX 77058 USA. Ist Astrofis Spaziale & Fis Cosmica, Rome, Italy. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Seu, R (reprint author), Univ Roma La Sapienza, INFOCOM, Via Eudossiana 18, I-00184 Rome, Italy. EM phillips@wustite.wustl.edu NR 30 TC 85 Z9 86 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 18 PY 2007 VL 112 IS E5 AR E05S05 DI 10.1029/2006JE002745 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 172YI UT WOS:000246840300001 ER PT J AU Miyamoto, H Yano, H Scheeres, DJ Abe, S Barnouin-Jha, O Cheng, AF Demura, H Gaskell, RW Hirata, N Ishiguro, M Michikami, T Nakamura, AM Nakamura, R Saito, J Sasaki, S AF Miyamoto, Hideaki Yano, Hajime Scheeres, Daniel J. Abe, Shinsuke Barnouin-Jha, Olivier Cheng, Andrew F. Demura, Hirohide Gaskell, Robert W. Hirata, Naru Ishiguro, Masateru Michikami, Tatsuhiro Nakamura, Akiko M. Nakamura, Ryosuke Saito, Jun Sasaki, Sho TI Regolith migration and sorting on asteroid Itokawa SO SCIENCE LA English DT Article ID INDUCED SEISMIC ACTIVITY; SIZE SEGREGATION; IMPACT; HAYABUSA; FRAGMENTS; VELOCITY; 433-EROS AB High-resolution images of the surface of asteroid Itokawa from the Hayabusa mission reveal it to be covered with unconsolidated millimeter-sized and larger gravels. Locations and morphologic characteristics of this gravel indicate that Itokawa has experienced considerable vibrations, which have triggered global-scale granular processes in its dry, vacuum, microgravity environment. These processes likely include granular convection, landslide-like granular migrations, and particle sorting, resulting in the segregation of the fine gravels into areas of potential lows. Granular processes become major resurfacing processes because of Itokawa's small size, implying that they can occur on other small asteroids should those have regolith. C1 Univ Tokyo, Univ Museum, Dept Museum Collect Utilizat Studies, Bunkyo Ku, Tokyo 1130033, Japan. Univ Tokyo, Dept Earth & Planetary Sci, Bunkyo Ku, Tokyo 1130033, Japan. Univ Tokyo, Dept Geosyst Engn, Bunkyo Ku, Tokyo 1138656, Japan. Planetary Sci Inst, Tucson, AZ 85719 USA. Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. Kobe Univ, Grad Sch Sci & Technol, Nada Ku, Kobe, Hyogo 6578501, Japan. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Univ Aizu, Dept Comp Software, Aizu Wakamatsu, Fukushima 9658580, Japan. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Seoul Natl Univ, Dept Astron, Seoul 151747, South Korea. Fukushima Natl Coll Technol, Iwaki, Fukushima 9708034, Japan. Natl Inst Adv Ind Sci & Technol, Tsukuba, Ibaraki 3068568, Japan. Tokai Univ, Sch Engn, Kanagawa 2591292, Japan. Natl Astron Observ Japan, Res Selenodesy Project Off, Mizusawa, Oshu 0230861, Japan. RP Miyamoto, H (reprint author), Univ Tokyo, Univ Museum, Dept Museum Collect Utilizat Studies, Bunkyo Ku, Hongo 7-3-1, Tokyo 1130033, Japan. EM hm@um.u-tokyo.ac.jp RI Miyamoto, Hideaki/B-9666-2008; Miyamoto, Hideaki/E-3381-2012; Barnouin, Olivier/I-7475-2015; Nakamura, Akiko/I-1993-2012 OI Barnouin, Olivier/0000-0002-3578-7750; Nakamura, Akiko/0000-0001-6990-8496 NR 25 TC 111 Z9 111 U1 1 U2 24 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 18 PY 2007 VL 316 IS 5827 BP 1011 EP 1014 DI 10.1126/science.1134390 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 168WF UT WOS:000246554000042 PM 17446355 ER PT J AU Chatfield, RB Guan, H Thompson, AM Smit, HGJ AF Chatfield, R. B. Guan, H. Thompson, A. M. Smit, H. G. J. TI Mechanisms for the intraseasonal variability of tropospheric ozone over the Indian Ocean during the winter monsoon SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MODIFIED-RESIDUAL METHOD; TROPICAL ATLANTIC; BOUNDARY-LAYER; MAPPING SPECTROMETER; EXPERIMENT INDOEX; SOUTHEAST-ASIA; AIR-POLLUTION; WAVE-ONE; TRANSPORT; SATELLITE AB [1] We synthesize daily sonde (vertical) information and daily satellite ( horizontal) information to provide an empirical description of ozone origins over the northern Indian Ocean during the INDOEX ( Indian Ocean Experiment) field campaign ( February - March 1999). This area is shown to be a significant portion of the "high-ozone tropics''. East-west O(3) features and their flow are identified, and ozone origins are compared to other tropical regions, using water vapor as a second tracer. In the study period, multiple processes contribute to O(3) column enhancements, their importance varying strongly by latitude: ( 1) Low-altitude O(3) pollution over the northern Indian Ocean mainly originates from the Indian subcontinent and is traceable to high emission areas. Convective activity south of Sri Lanka helps direct ozone outflow from the northern Indian subcontinent. ( 2) Middle tropospheric O(3) maxima over the northern Indian Ocean originate from various sources, often transitioning within a few hours. Convective venting of Asian pollutants can add 20 - 30 ppbv to the middle troposphere at 5 degrees N - 10 degrees N, alternating with stratospheric influence. ( 3) A number of cases suggest that strong mixing-in of stratospheric air along the subtropical jet raised tropospheric O(3) in early March by similar to 40 - 50 ppbv, especially poleward of similar to 10 degrees N. ( 4) Influences of lightning and large-scale biomass burning were not strong during this period, in contrast to the situation in Africa and the South Atlantic or locally in Southeast Asia. This work illustrates successes and limitations in approaches to synthesizing disparate information on trace-gas distributions taken from satellite retrieval products and ozonesondes. C1 NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. Bay Area Environm Res Inst, Sonoma, CA USA. Forschungszentrum Julich, Julich, Germany. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. RP Chatfield, RB (reprint author), NASA, Ames Res Ctr, Div Earth Sci, Mail Stop 245-5, Moffett Field, CA 94035 USA. EM chatfield@clio.arc.nasa.gov; guan@clio.arc.nasa.gov RI Smit, Herman/J-2397-2012; Thompson, Anne /C-3649-2014 OI Smit, Herman/0000-0002-2268-4189; Thompson, Anne /0000-0002-7829-0920 NR 53 TC 8 Z9 8 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 17 PY 2007 VL 112 IS D10 AR D10303 DI 10.1029/2006JD007347 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 172XU UT WOS:000246838900001 ER PT J AU Pour-Biazar, A McNider, RT Roselle, SJ Suggs, R Jedlovec, G Byun, DW Kim, S Lin, CJ Ho, TC Haines, S Dornblaser, B Cameron, R AF Pour-Biazar, Arastoo McNider, Richard T. Roselle, Shawn J. Suggs, Ron Jedlovec, Gary Byun, Daewon W. Kim, Soontae Lin, C. J. Ho, Thomas C. Haines, Stephanie Dornblaser, Bright Cameron, Robert TI Correcting photolysis rates on the basis of satellite observed clouds SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SIMPLE PHYSICAL MODEL; SOLAR-RADIATION; PARAMETERIZATION SCHEMES; ATMOSPHERE; AEROSOLS; ABSORPTION; PROFILES; SURFACE; URBAN AB [1] Clouds can significantly affect photochemical activities in the boundary layer by altering radiation intensity, and therefore their correct specification in the air quality models is of outmost importance. In this study we introduce a technique for using the satellite observed clouds to correct photolysis rates in photochemical models. This technique was implemented in EPA's Community Multiscale Air Quality modeling system (CMAQ) and was tested over a 10 day period in August 2000 that coincided with the Texas Air Quality Study (TexAQS). The simulations were performed at 4 and 12 km grid size domains over Texas, extending east to Mississippi, for the period of 24 to 31 August 2000. The results clearly indicate that inaccurate cloud prediction in the model can significantly alter the predicted atmospheric chemical composition within the boundary layer and exaggerate or underpredict ozone concentration. Cloud impact is acute and more pronounced over the emission source regions and can lead to large errors in the model predictions of ozone and its by-products. At some locations the errors in ozone concentration reached as high as 60 ppb which was mostly corrected by the use of our technique. Clouds also increased the lifetime of ozone precursors leading to their transport out of the source regions and causing further ozone production down-wind. Longer lifetime for nitrogen oxides (NOx = NO + NO2) and its transport over regions high in biogenic hydrocarbon emissions ( in the eastern part of the domain) led to increased ozone production that was missing in the control simulation. Over Houston-Galveston Bay area, the presence of clouds altered the chemical composition of the atmosphere and reduced the net surface removal of reactive nitrogen compounds. Use of satellite observed clouds significantly improved model predictions in areas impacted by clouds. Errors arising from an inconsistency in the cloud fields can impact the performance of photochemical models used for case studies as well as for air quality forecasting. Air quality forecast models often use the model results from the previous forecast ( or some adjusted form of it) for the initialization of the new forecast. Therefore such errors can propagate into the future forecasts, and the use of observed clouds in the preparation of initial concentrations for air quality forecasting could be beneficial. C1 Univ Alabama, Earth Syst Sci Ctr, Huntsville, AL 35899 USA. Univ Houston, Inst Multidimens Air Qual Studies, Houston, TX 77004 USA. Gulf Mexico OCS Reg, Minerals Management Serv, New Orleans, LA 70123 USA. Texas Commiss Environm Qual, Austin, TX 78711 USA. Lamar Univ, Dept Chem Engn, Beaumont, TX 77710 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Lamar Univ, Dept Civil Engn, Beaumont, TX 77710 USA. Univ Alabama, Dept Atmospher Sci, Huntsville, AL 35899 USA. NOAA, Atmospher Sci Modeling Div, Air Resources Lab, Res Triangle Pk, NC 27711 USA. US EPA, Natl Exposure Res Lab, Res Triangle Pk, NC 27711 USA. RP Pour-Biazar, A (reprint author), Univ Alabama, Earth Syst Sci Ctr, Huntsville, AL 35899 USA. EM biazar@nsstc.uah.edu RI Lin, Che-Jen/K-1808-2013 OI Lin, Che-Jen/0000-0001-5990-3093 NR 29 TC 19 Z9 19 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 17 PY 2007 VL 112 IS D10 AR D10302 DI 10.1029/2006JD007422 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 172XU UT WOS:000246838900002 ER PT J AU Schmidt, GA LeGrande, AN Hoffmann, G AF Schmidt, Gavin A. LeGrande, Allegra N. Hoffmann, Georg TI Water isotope expressions of intrinsic and forced variability in a coupled ocean-atmosphere model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; ANTARCTIC ICE CORES; SEA-ICE; INTERANNUAL VARIABILITY; GLOBAL PRECIPITATION; SURFACE-TEMPERATURE; CLIMATE VARIABILITY; DEUTERIUM EXCESS; STABLE-ISOTOPES; ASIAN MONSOON AB [1] Water isotopes provide a clear record of past climate variability but establishing their precise relationship to local or regional climate changes is the key to quantitative interpretations. We have incorporated water isotope tracers within the complete hydrological cycle of Goddard Institute for Space Studies coupled ocean-atmosphere model (ModelE) in order to assess these relationships. Using multicentennial simulations of the modern (preindustrial) and mid-Holocene ( 6 kyr BP) climate, we examine the internal variability and the forced response to orbital and greenhouse gas forcing. Modelled isotopic anomalies clearly reflect climatic changes and, particularly in the tropics, are more regionally coherent than the precipitation anomalies. Matches to observations at the mid-Holocene and over the instrumental period are good. We calculate water isotope-climate relationships for many patterns of intrinsic and for forced variability relevant to the Holocene, and we show that in general, calibrations depend on the nature of the climate change. Specifically, we examine relationships between isotopes in precipitation and local temperatures and precipitation amounts in the principal ice coring regions ( Greenland, Antarctica, and the tropical Andes) and the seawater isotope-salinity gradients in the ocean. We suggest that isotope-based climate reconstructions based on spatial patterns and nonlocal calibrations will be more robust than interpretations based on local relationships. C1 Columbia Univ, NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Lab Sci Climat & Environm, F-91191 Gif Sur Yvette, France. Columbia Univ, NASA, Ctr Climate Syst Res, New York, NY 10025 USA. RP Schmidt, GA (reprint author), Columbia Univ, NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM gschmidt@giss.nasa.gov; legrande@giss.nasa.gov; hoffmann@lsce.saclay.cea.fr RI Schmidt, Gavin/D-4427-2012; LeGrande, Allegra/D-8920-2012 OI Schmidt, Gavin/0000-0002-2258-0486; LeGrande, Allegra/0000-0002-5295-0062 NR 99 TC 147 Z9 151 U1 2 U2 22 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 17 PY 2007 VL 112 IS D10 AR D10103 DI 10.1029/2006JD007781 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 172XU UT WOS:000246838900004 ER PT J AU Yang, JY Comiso, JC AF Yang, Jiayan Comiso, Josefino C. TI An unexpected seasonal variability of salinity in the Beaufort Sea upper layer in 1996-1998 SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID ARCTIC-OCEAN; ICE MOTION; CIRCULATION; OSCILLATION; REGIMES AB [1] The salinity in the upper Beaufort Sea from the mixed layer to the thermocline layer was observed by drifting buoys from 1996 to 1998. The salinity in this depth range was lower in winter and higher in the summer, the exact opposite from what one would expect from the seasonal cycle of the freshwater flux associated with the ice melting/ freezing and river runoff. In this study, we calculated the daily Ekman transport and upwelling velocity in the Beaufort Sea, using both satellite and buoy data. In fall and winter months, the offshore transport of low-salinity water from the coastal area toward the interior where the buoys were located was observed to be strong. This horizontal Ekman transport led to the freshening of the surface Ekman layer in the buoy location. The convergence of the Ekman transport resulted in a strong downwelling in the offshore regions, and so the halocline and thermocline were pushed downward. The downwelling then results in the freshening of the subsurface salinity as observed by buoys. Other processes, such as lateral advection, may have also played a role in the subsurface freshening. The lack of in situ observations needed to estimate the salinity gradient makes it difficult to assess more accurately the contribution from lateral advection. A scaling analysis using the salinity climatology suggests that the lateral salinity advection, though considerably smaller than the vertical one, may not be negligible. C1 Woods Hole Oceanog Inst, Dept Phys Oceanog, Woods Hole, MA 02543 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher & Biospher Sci, Greenbelt, MD 20771 USA. RP Yang, JY (reprint author), Woods Hole Oceanog Inst, Dept Phys Oceanog, Woods Hole, MA 02543 USA. EM jyang@whoi.edu; josefino.c.comiso@nasa.gov NR 22 TC 4 Z9 4 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAY 17 PY 2007 VL 112 IS C5 AR C05034 DI 10.1029/2004JC002716 PG 13 WC Oceanography SC Oceanography GA 172YE UT WOS:000246839900001 ER PT J AU McEwen, AS Eliason, EM Bergstrom, JW Bridges, NT Hansen, CJ Delamere, WA Grant, JA Gulick, VC Herkenhoff, KE Keszthelyi, L Kirk, RL Mellon, MT Squyres, SW Thomas, N Weitz, CM AF McEwen, Alfred S. Eliason, Eric M. Bergstrom, James W. Bridges, Nathan T. Hansen, Candice J. Delamere, W. Alan Grant, John A. Gulick, Virginia C. Herkenhoff, Kenneth E. Keszthelyi, Laszlo Kirk, Randolph L. Mellon, Michael T. Squyres, Steven W. Thomas, Nicolas Weitz, Catherine M. TI Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE) SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Review ID POLAR LAYERED DEPOSITS; MARTIAN GEOLOGIC RECORD; ART. NO. 5111; GROUND ICE; VALLES-MARINERIS; LANDING SITE; NEAR-SURFACE; NORTHERN PLAINS; CLIMATE-CHANGE; SLOPE STREAKS AB [1] The HiRISE camera features a 0.5 m diameter primary mirror, 12 m effective focal length, and a focal plane system that can acquire images containing up to 28 Gb (gigabits) of data in as little as 6 seconds. HiRISE will provide detailed images (0.25 to 1.3 m/pixel) covering similar to 1% of the Martian surface during the 2-year Primary Science Phase (PSP) beginning November 2006. Most images will include color data covering 20% of the potential field of view. A top priority is to acquire similar to 1000 stereo pairs and apply precision geometric corrections to enable topographic measurements to better than 25 cm vertical precision. We expect to return more than 12 Tb of HiRISE data during the 2-year PSP, and use pixel binning, conversion from 14 to 8 bit values, and a lossless compression system to increase coverage. HiRISE images are acquired via 14 CCD detectors, each with 2 output channels, and with multiple choices for pixel binning and number of Time Delay and Integration lines. HiRISE will support Mars exploration by locating and characterizing past, present, and future landing sites, unsuccessful landing sites, and past and potentially future rover traverses. We will investigate cratering, volcanism, tectonism, hydrology, sedimentary processes, stratigraphy, aeolian processes, mass wasting, landscape evolution, seasonal processes, climate change, spectrophotometry, glacial and periglacial processes, polar geology, and regolith properties. An Internet Web site (HiWeb) will enable anyone in the world to suggest HiRISE targets on Mars and to easily locate, view, and download HiRISE data products. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Ball Aerosp & Technol Corp, Boulder, CO 80301 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Delamere Support Syst, Boulder, CO 80304 USA. Smithsonian Inst, Natl Air & Space Museum, Washington, DC 20560 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Moffett Field, CA 94035 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Univ Bern, Inst Phys, CH-3012 Bern, Switzerland. Planetary Sci Inst, Tucson, AZ 85719 USA. RP McEwen, AS (reprint author), Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. EM mcewen@pirl.lpl.arizona.edu RI Mellon, Michael/C-3456-2016; Bridges, Nathan/D-6341-2016 NR 243 TC 162 Z9 165 U1 6 U2 63 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 17 PY 2007 VL 112 IS E5 AR E05S02 DI 10.1029/2005JE002605 PG 40 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 172YH UT WOS:000246840200001 ER PT J AU Nimmo, F Spencer, JR Pappalardo, RT Mullen, ME AF Nimmo, F. Spencer, J. R. Pappalardo, R. T. Mullen, M. E. TI Shear heating as the origin of the plumes and heat flux on Enceladus SO NATURE LA English DT Article ID STRIKE-SLIP FAULTS; TIDAL STRESSES; EUROPA; ICE; EVOLUTION; PATTERNS; NUCLEI AB Enceladus, a small icy satellite of Saturn, has active plumes jetting from localized fractures ('tiger stripes') within an area of high heat flux near the south pole(1-4). The plume characteristics(1) and local high heat flux(2) have been ascribed either to the presence of liquid water within a few tens of metres of the surface(1), or the decomposition of clathrates(5). Neither model addresses how delivery of internal heat to the near-surface is sustained. Here we show that the most likely explanation for the heat(2) and vapour production(6,7) is shear heating by tidally driven lateral (strike-slip) fault motion(1,8,9) with displacement of similar to 0.5 m over a tidal period. Vapour produced by this heating may escape as plumes through cracks reopened by the tidal stresses(10). The ice shell thickness needed to produce the observed heat flux is at least 5 km. The tidal displacements required imply a Love number of h(2)> 0.01, suggesting that the ice shell is decoupled from the silicate interior by a subsurface ocean. We predict that the tiger-stripe regions with highest relative temperatures will be the lower-latitude branch of Damascus, Cairo around 60 degrees W longitude and Alexandria around 150 degrees W longitude. C1 Univ Calif Santa Cruz, Dept Earth & Planetary Sci, Santa Cruz, CA 95064 USA. SW Res Inst, Dept Space Studies, Boulder, CO 80304 USA. CALTECH, Jet Prop Lab, Planetary Sci & Life Detect Sect, Pasadena, CA 91109 USA. Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. RP Nimmo, F (reprint author), Univ Calif Santa Cruz, Dept Earth & Planetary Sci, 1156 High St, Santa Cruz, CA 95064 USA. EM fnimmo@es.ucsc.edu NR 28 TC 124 Z9 125 U1 4 U2 23 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 17 PY 2007 VL 447 IS 7142 BP 289 EP 291 DI 10.1038/nature05783 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 168JK UT WOS:000246520300038 PM 17507976 ER PT J AU Hurford, TA Helfenstein, P Hoppa, GV Greenberg, R Bills, BG AF Hurford, T. A. Helfenstein, P. Hoppa, G. V. Greenberg, R. Bills, B. G. TI Eruptions arising from tidally controlled periodic openings of rifts on Enceladus SO NATURE LA English DT Article ID EUROPA AB In 2005, plumes were detected near the south polar region of Enceladus(1), a small icy satellite of Saturn. Observations of the south pole revealed large rifts in the crust, informally called 'tiger stripes', which exhibit higher temperatures than the surrounding terrain and are probably sources of the observed eruptions(2). Models of the ultimate interior source for the eruptions are under consideration (1,3-5). Other models of an expanding plume(6) require eruptions from discrete sources, as well as less voluminous eruptions from a more extended source, to match the observations. No physical mechanism that matches the observations has been identified to control these eruptions. Here we report a mechanism in which temporal variations in tidal stress open and close the tiger-stripe rifts, governing the timing of eruptions. During each orbit, every portion of each tiger stripe rift spends about half the time in tension, which allows the rift to open, exposing volatiles, and allowing eruptions. In a complementary process, periodic shear stress along the rifts also generates heat along their lengths(7-9), which has the capacity to enhance eruptions. Plume activity is expected to vary periodically, affecting the injection of material into Saturn's E ring(10) and its formation, evolution and structure. Moreover, the stresses controlling eruptions imply that Enceladus' icy shell behaves as a thin elastic layer, perhaps only a few tens of kilometres thick. C1 NASA, Goddard Space Flight Ctr, Planetary Geodynam Lab, Greenbelt, MD 20771 USA. Cornell Univ, CRSR, Ithaca, NY 14853 USA. Raytheon Co, Woburn, MA 01801 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Calif San Diego, Scripps Inst Oceanog, Inst Geophys & Planetary Phys, La Jolla, CA 92093 USA. RP Hurford, TA (reprint author), NASA, Goddard Space Flight Ctr, Planetary Geodynam Lab, Greenbelt, MD 20771 USA. EM hurfordt@core2.gsfc.nasa.gov RI Bills, Bruce/C-1156-2008; Hurford, Terry/F-2625-2012 NR 23 TC 74 Z9 75 U1 1 U2 11 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 17 PY 2007 VL 447 IS 7142 BP 292 EP 294 DI 10.1038/nature05821 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 168JK UT WOS:000246520300039 PM 17507977 ER PT J AU Jeong, MJ Li, ZQ Andrews, E Tsay, SC AF Jeong, Myeong-Jae Li, Zhanqing Andrews, Elisabeth Tsay, Si-Chee TI Effect of aerosol humidification on the column aerosol optical thickness over the Atmospheric Radiation Measurement Southern Great Plains site SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MID-ATLANTIC COAST; LIGHT-SCATTERING; UNITED-STATES; IN-SITU; RELATIVE-HUMIDITY; SULFATE AEROSOLS; CLOUD; SATELLITE; OCEAN; SMOKE AB [1] This study investigates the aerosol humidification effect (AHE) using 70 profiles of the aerosol scattering coefficients at high ( similar to 80%) and low ( similar to 40%) relative humidity ( RH) levels and absorption coefficient at a low RH level obtained by a light aircraft (Cessna C- 172N) over the Southern Great Plains (SGP) site from April 2003 to June 2004. The column aerosol humidification factor, R( RH), defined as the ratio of the aerosol optical thickness (AOT) at the ambient RH to that at RH = 40% throughout the column rarely exceeded 1.3 ( mean, 1.09 +/- 0.12) over the SGP site. However, for an atmospheric column of a constant RH = 85%, R( RH) is greater than 1.5 for the majority of cases ( mean, 1.57 +/- 0.28). R( RH) was fitted to a function of column RH based on this unique aerosol data set. Several methods were proposed to estimate R( RH) for use when direct measurements of R( RH) are not available. It was found that the relationship between R( RH) and aerosol extinction coefficient weighted column-mean RH works best. Performance of other methods depends on the measurements available. Sensitivity of R( RH) to a very humid ( RH = 99%) layer with varying thickness values (0.1 - 0.3 km) is examined. The results indicate that the AHE on the AOT over the SGP site is not likely to exceed 50% on the average. The methods and results of this study may be utilized with caution to remove the AHE from the AOT retrieved from satellite or automated Sun photometer measurements, which will be useful for studies on aerosol indirect effect or quantifying cloud contamination in aerosol retrievals. C1 Univ Maryland, Dept Atmospher & Ocean Sci, College Pk, MD 20742 USA. Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Jeong, MJ (reprint author), Univ Maryland, Dept Atmospher & Ocean Sci, College Pk, MD 20742 USA. EM mjeong@climate.gsfc.nasa.gov RI Jeong, Myeong/B-8803-2008; Li, Zhanqing/F-4424-2010; Tsay, Si-Chee/J-1147-2014 OI Li, Zhanqing/0000-0001-6737-382X; NR 42 TC 26 Z9 26 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 16 PY 2007 VL 112 IS D10 AR D10202 DI 10.1029/2006JD007176 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 172XT UT WOS:000246838800002 ER PT J AU Su, WY Charlock, TP Rose, FG Rutan, D AF Su, Wenying Charlock, Thomas P. Rose, Fred G. Rutan, David TI Photosynthetically active radiation from Clouds and the Earth's Radiant Energy System (CERES) products SO JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES LA English DT Article ID SURFACE SOLAR IRRADIANCE; K-DISTRIBUTION METHOD; CARBON-DIOXIDE; ULTRAVIOLET-RADIATION; AEROSOL RETRIEVALS; SATELLITE; MODEL; SPECTRORADIOMETER; ATMOSPHERE; PARAMETERIZATION AB [1] We describe a method that retrieves surface photosynthetically active radiation ( PAR) and its direct and diffuse components from the Surface and Atmospheric Radiation Budget (SARB) product of Clouds and the Earth's Radiant Energy System (CERES). The shortwave spectrum in the SARB Edition 2 is calculated in 15 bands, 4 of which are used to develop the PAR, in conjunction with the look-up tables described in this paper. We apply these look-up tables to existing CERES Terra Edition 2 products. The new retrieved surface PAR is validated with LI-COR PAR measurements at seven Surface Radiation Budget Network (SURFRAD) sites using data from March 2000 to June 2005. The relative bias of retrieved all-sky PAR at the SURFRAD sites is 4.6% ( positive sign indicating retrieval exceeds measurement), and 54% of the all-sky samples are within the +/- 10% uncertainty of the LI-COR PAR measurements. The satellite field-of-view (FOV) is more representative of the ground instrument FOV under clear conditions, so 89% of clear-sky retrievals are within the uncertainty of the LI-COR PAR measurements at SURFRAD sites with positive biases at most sites. The retrieved PAR is also validated at the Atmospheric Radiation Measurement ( ARM) Southern Great Plains Central Facility (CF) site using data from October 2003 to June 2004 for those FOVs having both LI-COR and Rotating Shadowband Spectroradiometer (RSS) ground measurements; for this small domain, all-sky relative biases are again positive (1.9%) for LI-COR but negative ( - 4.2%) for RSS. The direct-to-diffuse ratio derived from CERES is smaller than that from RSS for both clear and cloudy conditions. CERES also retrieves the broadband shortwave insolation, and the relative biases for the broadband retrievals are much less than those for PAR at the above sites. It appears that some of the ground-based measurements of PAR do not have the fidelity of those for broadband shortwave insolation. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Hampton Univ, Dept Atmospher & Planetary Sci, Hampton, VA 23668 USA. Sci Syst & Applicat Inc, Hampton, VA 23666 USA. RP Su, WY (reprint author), Sci Syst & Applicat Inc, 1 Enterprise Pkwy, Hampton, VA 23666 USA. EM w.su@larc.nasa.gov; thomas.p.charlock@nasa.gov; f.g.rose@larc.nasa.gov; d.a.rutan@larc.nasa.gov OI Rose, Fred G/0000-0003-0769-0772 NR 52 TC 8 Z9 9 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-BIOGEO JI J. Geophys. Res.-Biogeosci. PD MAY 16 PY 2007 VL 112 IS G2 AR G02022 DI 10.1029/2006JG000290 PG 11 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA 172XY UT WOS:000246839300002 ER PT J AU Maurer, JA White, VE Dougherty, DA Nadeau, JL AF Maurer, Joshua A. White, Victor E. Dougherty, Dennis A. Nadeau, Jay L. TI Reconstitution of ion channels in agarose-supported silicon orifices SO BIOSENSORS & BIOELECTRONICS LA English DT Article DE ion channel; MEMS; wafer; supported bilayer; single-channel; electrophysiology ID LIPID BILAYER-MEMBRANES; MICROMACHINED SUPPORTS; MODEL MEMBRANES; ALAMETHICIN; BIOSENSOR; INTERFACE; DIFFUSION; CHIP AB A silicon wafer with eight individually addressable microfabricated orifices was used for ion channel reconstitution and single-channel recording. A spin-on fluoropolymer created an insulating, hydrophobic interface that was more stable than silane. Total capacitance of the membranes was < 10 pF, making it easy to evaluate bilayer formation by capacitance change. Orifices of 50-250 mu m diameter were tested for ease and stability of bilayer formation; only those > 100 mu m resulted in ion channel function. Bilayers were formed over an agarose supporting layer by application of lipid in decane with a paintbrush; a second layer of agarose could then be added to stabilize the structure and prevent evaporation. Microfluidic wells were constructed on glass plates for ease of assembly and visualization of fluid flow, as well as high-resolution microscopy for studies using fluorescent lipids and channels. The microfluidics consisted of reversibly bonded silicone rubber (PDMS), so that the entire device could be washed and reused. Total electrical noise in the device was low enough to permit single-channel resolution. Successful channel insertions were observed with a self-assembling ionophore (alamethicin) as well as a complex, vesicle-associated mammalian channel (human glycine receptor, GlyR). A "hands-free" approach to bilayer formation was also tested, where lipid in solvent was applied to the wafer by spin-coating, dried, and then "sandwiched" between layers of agarose above and below the nitride. Electrical properties consistent with bilayers were observed and alamethicin recordings were obtained, however this method is not compatible with the fusion of vesicles containing mammalian channels. (c) 2006 Elsevier B.V. All rights reserved. C1 CALTECH, Div Chem & Chem Engn, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nadeau, JL (reprint author), McGill Univ, Dept Biomed Engn, 3775 Rue Univ, Montreal, PQ H3A 2B4, Canada. EM jay.nadeau@mcgill.ca OI Maurer, Joshua/0000-0002-6663-0721 FU NIGMS NIH HHS [GM-062532] NR 31 TC 27 Z9 27 U1 0 U2 10 PU ELSEVIER ADVANCED TECHNOLOGY PI OXFORD PA OXFORD FULFILLMENT CENTRE THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0956-5663 J9 BIOSENS BIOELECTRON JI Biosens. Bioelectron. PD MAY 15 PY 2007 VL 22 IS 11 BP 2577 EP 2584 DI 10.1016/j.bios.2006.10.017 PG 8 WC Biophysics; Biotechnology & Applied Microbiology; Chemistry, Analytical; Electrochemistry; Nanoscience & Nanotechnology SC Biophysics; Biotechnology & Applied Microbiology; Chemistry; Electrochemistry; Science & Technology - Other Topics GA 166MH UT WOS:000246382500026 PM 17098413 ER PT J AU Malavergne, V Tarrida, M Combes, R Bureau, H Jones, J Schwandt, C AF Malavergne, Valerie Tarrida, Martine Combes, Rossana Bureau, Helene Jones, John Schwandt, Craig TI New high-pressure and high-temperature metal/silicate partitioning of U and Pb: Implications for the cores of the Earth and Mars SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Review ID ANHYDROUS PERIDOTITE KLB-1; IRON-SULFUR COMPOUND; NI-S SYSTEM; SIDEROPHILE ELEMENTS; MELTING EXPERIMENTS; THERMAL EVOLUTION; PLANETARY CORES; SILICATE MELTS; EXPERIMENTAL CONSTRAINTS; CHEMICAL-COMPOSITION AB in order to quantify possible fractionation of U and Pb into a metallic core, we have performed piston cylinder and multi-anvil press experiments at high pressure (up to 20 GPa) and high temperature (up to 2400 degrees C) and obtained the distribution coefficient Dmetal-silicate and the exchange partition coefficient Kmetal-silicate for these elements between metal and silicates (mineral or liquid). D-metal-silicate(Pb) and Du(metal-silicate)(U) depend strongly on the S content of the metallic phase, and also on the oxygen fugacity, in agreement with an effective valence state of 4 for U in silicates and 2 for Pb in silicates. K-d metal-silicate(Pb) and K-d (U)(metal-silicate) show no discernable pressure and temperature trend. U remains lithophile even at high pressure and high temperature but its lithophile nature decreases at very low oxygen fugacity. From our experimental data, it was possible to calculate the U and Pb contents of the cores of Mars and Earth under core-mantle equilibrium conditions at high pressure and high temperature. From the Dmetal-silicate, of the present study, we obtained that: 0.008 ppm < Pb-in (the core) <4.4 ppm, and 0.0003 ppb < U-in (the core) < 0.63 ppb, depending on whether the metal is S-ftee or S-saturated respectively, and if the mantle was molten or solid during the segregation process of the Earth's core around Delta IW-2. For Mars, based on a core segregation process around Delta IW-1, we obtained that: 0.005 ppm < Pbin the-re < 3 pprn, and 0.00002 ppb < U-in the core < 0.05 ppb, depending on the metallic composition: S-free or S-saturated respectively. Our results suggest that the low concentration of Pb in the terrestrial mantle could not be explained by an early Pb sequestration in the Earth's core even if S is the dominant light element of the core. If we assume a magma ocean scenario, U might produced a maximum value of 1.5% of the total heat budget of the core with a segregation occurring below Delta IW-3. The values found in the present study for U in the Martian core suggest that the magnetic field activity of Mars before similar to 0.5 b.y. after its formation would be difficult to ascribe to the decay of U alone. (c) 2007 Elsevier Ltd. All rights reserved. C1 Lunar & Planetary Inst, Houston, TX USA. Univ Marne La Vallee, Lab Geomat, F-77454 Marne La Vallee, France. CE Saclay, CNRS, CEA, LPS, F-91191 Gif Sur Yvette, France. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Jacobs Sverdrup, ESCG, Houston, TX USA. RP Malavergne, V (reprint author), Lunar & Planetary Inst, 3600 Bay Area Blvd, Houston, TX USA. EM malaverg@univ-mlv.fr NR 119 TC 34 Z9 34 U1 1 U2 16 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 EI 1872-9533 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY 15 PY 2007 VL 71 IS 10 BP 2637 EP 2655 DI 10.1016/j.gca.2007.03.011 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 170XN UT WOS:000246699600013 ER PT J AU Boxe, CS Bodsgard, BR Smythe, W Leu, MT AF Boxe, C. S. Bodsgard, B. R. Smythe, W. Leu, M. T. TI Grain sizes, surface areas, and porosities of vapor-deposited H2O ices used to simulate planetary icy surfaces SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article; Proceedings Paper CT International Electrokinetics Conference (Elkin) CY JUN 25-29, 2006 CL Nancy, FRANCE DE ices; grain sizes; surface areas; porosity; sintering; metamorphism ID GALILEAN SATELLITES; WATER-ICE; SULFURIC-ACID; AMORPHOUS ICE; ADSORPTION; GASES; FILMS; SPECTROSCOPY; MORPHOLOGY; SULFATE AB Mean grain sizes and specific surface areas (SSAs) of ice substrates formed by vapor deposition at low temperatures are of importance in simulating external surfaces of icy satellites in the solar system. Environmental scanning electron microscopy (ESEM) was used to obtain granule sizes and to observe the phase of ice granules prepared on borosilicate, silicon, and metallic plates. Ices prepared at a temperature lower than 140 K appear to be amorphous, and their granule sizes are typically submicrometer. At slightly warmer temperatures, near 180-200 K, ice films are composed of either hexagonal or cubic granules with sizes up to a few micrometers. When briefly annealed to even warmer temperatures, ice granule sizes approach similar to 10 mu m. SSAs of ice substrates were determined from BET (Brunauer, Emmett, and Teller) analysis of gas adsorption isotherms in the temperature range from 83.5 to 261 K. SSAs decrease drastically from 102 m(2)/g at 83.5 K to 0.87 m(2)/g at 150 K and further decrease slowly to 0.22 m(2)/g at 261 K, suggesting that the transition from amorphous to crystalline forms occurs at similar to 150 K. The overall decrease in SSAs is primarily due to metamorphism and sintering. These results are comparable to recent field and laboratory measurements. Possible implications for theoretical models of icy satellites of outer planets using remote sensing techniques are also discussed. (C) 2007 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Div Sci, Pasadena, CA 91109 USA. RP Leu, MT (reprint author), CALTECH, Jet Prop Lab, Div Sci, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM ming-taun.leu@jpl.nasa.gov NR 35 TC 5 Z9 5 U1 1 U2 7 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD MAY 15 PY 2007 VL 309 IS 2 BP 412 EP 418 DI 10.1016/j.jcis.2007.01.008 PG 7 WC Chemistry, Physical SC Chemistry GA 160UL UT WOS:000245967700027 PM 17306289 ER PT J AU Leslie, FW Ramachandran, N AF Leslie, F. W. Ramachandran, N. TI Stability of magnetically suppressed solutal convection in crystal growth from solutions SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE biocrystallization; convection; fluid flows; magnetic fields; growth from solutions; microgravity conditions ID PROTEIN CRYSTALLIZATION; MICROGRAVITY; FUTURE; FLOWS; SPACE; FIELD AB Convective motions during different crystal growth processes are known to interfere with the quality of the growth process and are hypothesized to be detrimental to the quality of the grown crystal. In crystal growth from solutions for example, without fluid interfaces and free surfaces, gravity driven phenomena such as thermal and solutal buoyancy effects and sedimentation are the primary causes of fluid flows in the system. While crystallization in microgravity can approach diffusion limited growth conditions (no convection), terrestrially strong magnetic fields can be used to control fluid flow and sedimentation effects. In this work, a theory is presented on the stability of solutal convection of a magnetized fluid in the presence of a magnetic field. The requirements for stability are developed and compared to experiments performed within the bore of a superconducting magnet. The theoretical predictions are in good agreement with the experiments and show solutal convection can be stabilized if the surrounding fluid has larger magnetic susceptibility and the magnetic field has a specific structure. Discussion on the application of the technique to protein crystallization is also provided. (C) 2007 Elsevier B.V. All rights reserved. C1 BAE SYSTEMS Analyt Solut Inc, Huntsville, AL 35806 USA. NASA, George C Marshall Space Flight Ctr, XD42, Sci Directorate, Huntsville, AL 35812 USA. RP Ramachandran, N (reprint author), BAE SYSTEMS Analyt Solut Inc, Huntsville, AL 35806 USA. EM narayanan.ramachandran-1@nasa.gov NR 17 TC 13 Z9 15 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD MAY 15 PY 2007 VL 303 IS 2 BP 597 EP 606 DI 10.1016/j.jcrysgro.2006.12.058 PG 10 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 171NE UT WOS:000246741900035 ER PT J AU Kollias, P Tselioudis, G Albrecht, BA AF Kollias, Pavlos Tselioudis, George Albrecht, Bruce A. TI Cloud climatology at the Southern Great Plains and the layer structure, drizzle, and atmospheric modes of continental stratus SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RADIATION MEASUREMENT PROGRAM; GENERAL-CIRCULATION MODELS; SGP CENTRAL FACILITY; RADAR OBSERVATIONS; BUDGET EXPERIMENT; ARM CART; TEMPERATURE; DEPENDENCE; FRACTION; SITE AB [1] Long-term (6.5 years) cloud observations from the Atmospheric Radiation Measurements ( ARM) program Southern Great Plains (SGP) climate research facility in Oklahoma are used to develop detailed cloud climatology. Clouds are classified with respect to their altitude ( low, middle, and high), vertical development, and the presence of multilayer clouds. Single-layered cirrus, middle or low clouds were observed a total of 23% of the time the MilliMeter Cloud Radar (MMCR) was operating, and multilayer clouds were observed 20.5% of the time. Boundary layer clouds exhibit the strongest seasonal variability because of continental stratus associated with midlatitude frontal systems. Cirrus clouds are the most frequently observed cloud type and exhibit strong seasonal variability in cloud base height ( higher cloud base during the summer months) and relatively constant cloud fraction. The majority of middle-level clouds are shallow with vertical extent less than 1 km. No strong seasonal cycle in the fractional coverage of multilayer clouds is observed. Continental stratus clouds exhibit strong seasonal variability with maximum occurrence during the cold seasons. Nondrizzling stratus clouds exhibit a bimodal seasonal variability with maximum occurrences in the fall and spring, while drizzling stratus occur most frequently in the winter. Thermodynamic and dynamic variables from soundings and the European Centre for Medium-Range Weather Forecasts Model (ECMWF) analyses at the SGP site illustrate an interesting coupling between strong large-scale forcing and the formation of single-layered ( no other cloud layer is present) continental stratus clouds. Single-layered stratus clouds ( drizzling and nondrizzling) exhibit a strong correlation with positive omega at 500 mbar and strong northerly flow. C1 Brookhaven Natl Lab, Div Atmospher Sci, Upton, NY 11973 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Miami, Div Meteorol & Phys Oceanog, Miami, FL 33149 USA. RP Kollias, P (reprint author), McGill Univ, Dept Atmospher & Ocean Sci, 805 Sherbrooke St W, Montreal, PQ H3A 2K6, Canada. EM pavlos.kollias@mcgill.ca NR 31 TC 23 Z9 24 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 15 PY 2007 VL 112 IS D9 AR D09116 DI 10.1029/2006JD007307 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 172XR UT WOS:000246838600007 ER PT J AU Remsberg, EE AF Remsberg, Ellis E. TI A reanalysis for the seasonal and longer-period cycles and the trends in middle-atmosphere temperature from the Halogen Occultation Experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID QUASI-BIENNIAL OSCILLATION; MESOSPHERIC TEMPERATURE; SOLAR-CYCLE; GLOBAL VARIABILITY; ART.; MODEL; STRATOSPHERE AB [1] Remsberg and Deaver ( 2005) reported on multiple linear regression ( MLR) analyses of time series of middle-atmosphere temperature versus pressure ( or T( p)) profiles from the Halogen Occultation Experiment (HALOE) for its seasonal and longer-period cycles. Their results are extended herein to just over 14 years and updated to properly account for the effects of autocorrelation in their time series of zonally averaged data. The updated seasonal and annual average terms are provided, and they can be used to generate near-global, temperature distributions from 2 to 0.007 hPa that are representative of the period 1991 - 2005. Quasi-biennial oscillation (QBO-like; 853-day) and subbiennial (640-day) terms are also resolved and provided, and they exhibit good consistency across the range of latitudes and pressure altitudes. Further, somewhat exploratory analyses of the residuals from each of the 208 time series yield significant 11-year solar cycle ( or SC-like) and linear trend terms at a number of latitudes and levels. Where significant, those terms are included in the final MLR models. The amplitudes of the SC-like terms for the mesosphere agree reasonably with calculations of the direct solar radiative effects for T( p). Those SC-like amplitudes increase by about a factor of 2 from the lower to the upper mesosphere and are larger at the middle than at the low latitudes. The diagnosed T( p) cooling trends from HALOE for the low latitudes are in the range of - 0.5 to - 1.0 K/decade, which is in good agreement with the findings from models of the radiative effects on pressure surfaces due to known increases in atmospheric CO2. The diagnosed HALOE trends are somewhat larger than those predicted with models for middle latitudes of the upper mesosphere. Cooling trends also are found to be increasing from about - 0.5 to - 1.0 K/decade from 1 to 2 hPa of the upper stratosphere, also in reasonable agreement with modeled results. C1 NASA, Sci Directorate, Langley Res Ctr, Hampton, VA 23681 USA. RP Remsberg, EE (reprint author), NASA, Sci Directorate, Langley Res Ctr, Mail Stop 401B, Hampton, VA 23681 USA. EM ellis.e.remsberg@nasa.gov NR 35 TC 14 Z9 14 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 15 PY 2007 VL 112 IS D9 AR D09118 DI 10.1029/2006JD007489 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 172XR UT WOS:000246838600010 ER PT J AU Rind, D Lerner, J Jonas, J McLinden, C AF Rind, D. Lerner, J. Jonas, J. McLinden, C. TI Effects of resolution and model physics on tracer transports in the NASA Goddard Institute for Space Studies general circulation models SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID COMMUNITY CLIMATE MODEL; DOUBLED CO2 CLIMATE; HORIZONTAL RESOLUTION; ATMOSPHERIC TRANSPORT; ECMWF MODEL; STRATOSPHERIC MODELS; VERTICAL RESOLUTION; SIMULATED CLIMATE; DYNAMICAL MODEL; DIAGNOSTIC-TOOL AB [1] We explore the dependency of general circulation model tracer transports on model physics and horizontal and vertical resolution. We use NASA Goddard Institute for Space Studies (GISS) Model E at 4 degrees x 5 degrees with 20 and 23 layers and the GISS Global Climate Middle Atmosphere Model 3 at 4 degrees x 5 degrees with 23 and 53 layers and at 2 degrees x 2.5 degrees with 53 and 102 layers. The online tracers employed are CO2, CH4, N2O, CFC-11, SF6, Rn-222, bomb C-14, and O-3. Model experiments are done two ways: with specified stratospheric ozone or with the stratospheric ozone tracer used for atmospheric radiation calculations. The results show that when model physics produces greater precipitation over land in the Northern Hemisphere summer monsoon region, as occurs in Model 3, the associated dynamics ( stronger Hadley cell) and subgrid-scale transports lead to faster and more realistic interhemispheric transport. Increased vertical resolution results in some increase in vertical mixing between the boundary layer and upper troposphere, due to both convective and synoptic-scale influences. A better resolved boundary layer does not result in higher surface concentrations, as the influence of various processes ( convection, turbulence, rainfall) contribute in different ways. Transport into, within, and out of the stratosphere is faster ( less realistic) with the coarser resolution models as wave forcing generates a stronger residual circulation. It is also faster in Model E as a result of its larger parameterized orographic gravity wave drag; the latter also results in a more "leaky'' stratospheric tropical pipe. Horizontal resolution in this range by itself has minimal impact on most transports ( although for active chemical tracers, photochemistry has been shown to be resolution-dependent). In contrast, finer vertical resolution leads to faster interhemispheric transport, slower mixing into and out of the stratosphere, and greater age of stratospheric air. When both resolutions are increased, the largest changes are seen. The interactive stratospheric ozone tracer, without an ozone hole parameterization, produced ( as expected) greater ozone values than observations in the lower stratosphere. The associated temperature warming of a few degrees Celsius increased atmospheric stability and altered the tropospheric wave forcing of the Brewer Dobson circulation such that the stratospheric age of air increased by some 30%. This large sensitivity has implications for past and future stratospheric circulations and for the ability of climate perturbations to affect the stratosphere. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Ctr Climate Syst Res, New York, NY USA. Meteorol Serv Canada, Downsview, ON, Canada. RP Rind, D (reprint author), NASA, Goddard Inst Space Studies, New York, NY 10025 USA. EM drind@giss.nasa.gov RI McLinden, Chris/A-7710-2010 OI McLinden, Chris/0000-0001-5054-1380 NR 78 TC 55 Z9 56 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 15 PY 2007 VL 112 IS D9 AR D09315 DI 10.1029/2006JD007476 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 172XR UT WOS:000246838600009 ER PT J AU Thompson, AM Stone, JB Witte, JC Miller, SK Oltmans, SJ Kucsera, TL Ross, KL Pickering, KE Merrill, JT Forbes, G Tarasick, DW Joseph, E Schmidlin, FJ McMillan, WW Warner, J Hintsa, EJ Johnson, JE AF Thompson, Anne M. Stone, Jesse B. Witte, Jacquelyn C. Miller, Sonya K. Oltmans, Samuel J. Kucsera, Tom L. Ross, Kelly L. Pickering, Kenneth E. Merrill, John T. Forbes, Gerry Tarasick, David W. Joseph, Everette Schmidlin, F. J. McMillan, W. Wallace Warner, Juying Hintsa, Eric J. Johnson, James E. TI Intercontinental Chemical Transport Experiment Ozonesonde Network Study (IONS) 2004: 2. Tropospheric ozone budgets and variability over northeastern North America SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPICAL ATLANTIC; HIGH-LATITUDE; CLIMATOLOGY; EMISSIONS; CANADA; TRACE AB [1] Daily ozone soundings taken from the R/V Ronald H. Brown from 7 July through 11 August 2004 as part of the Intercontinental Chemical Transport Experiment (INTEX) Ozonesonde Network Study ( IONS) are used to investigate the vertical structure of ozone over the Gulf of Maine and to characterize variability in sources of tropospheric ozone: stratosphere, regional convection and lightning, advection, and local boundary layer pollution. These soundings were part of a network of twelve IONS (http://croc.gsfc.nasa.gov/intex/ions.html) stations that launched ozonesonde-radiosonde packages over the United States and maritime Canada during the INTEX/ International Consortium for Atmospheric Research on Transport and Transformation (ICARTT)/New England Air Quality Study (NEAQS) project from 1 July to 15 August 2004. Four of the IONS stations were in mid-Atlantic and northeast United States; four were in southeastern Canada. Although the INTEX/ ICARTT goal was to examine pollution influences under stable high-pressure systems, northeastern North America ( NENA) during IONS was dominated by weak frontal systems that mixed aged pollution and stratospheric ozone with ozone from more recent pollution and lightning. These sources are quantified to give tropospheric ozone budgets for individual soundings that are consistent with tracers and meteorological analyses. On average, for NENA stations in July-August 2004, tropospheric ozone was composed of the following: 10 - 15% each local boundary layer and regional sources ( the latter including that due to lightning-derived NO) and 20 - 25% stratospheric ozone, with the balance ( similar to 50%) a mixture of recently advected ozone and aged air of indeterminate origin. C1 Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. NOAA, Earth Syst Res Lab, Boulder, CO 80305 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. Environm Canada, Meteorol Serv Ctr, Downsview, ON M3H 5T4, Canada. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Environm Canada Sable Isl, Dartmouth, NS B2Y 2N6, Canada. Harvard Univ, Dept Chem & Chem Biol, Cambridge, MA 02138 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98195 USA. Howard Univ, Dept Phys & Astron, Washington, DC 20059 USA. Univ Maryland Baltimore Cty, Joint Ctr Environm Technol, Baltimore, MD 21250 USA. Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. RP Thompson, AM (reprint author), Penn State Univ, Dept Meteorol, 503 Walker Bldg, University Pk, PA 16802 USA. EM anne@met.psu.edu; witte@gavial.gsfc.nasa.gov; samuel.j.oltmans@noaa.gov; tlk@croc.gsfc.nasa.gov; pickerin@gator1.gsfc.nasa.gov; jmerrill@gso.uri.edu; gerry.forbes@ec.gc.ca; david.tarasick@ec.gc.ca; ejoseph@howard.edu; fjs@osb1.wff.nasa.gov; mcmillan@umbc.edu; juying@umbc.edu; ehintsa@nsf.gov; james.e.johnson@noaa.gov RI Pickering, Kenneth/E-6274-2012; Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 39 TC 54 Z9 54 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 15 PY 2007 VL 112 IS D12 AR D12S13 DI 10.1029/2006JD007670 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 172XX UT WOS:000246839200002 ER PT J AU Thompson, AM Stone, JB Witte, JC Miller, SK Pierce, RB Chatfield, RB Oltmans, SJ Cooper, OR Loucks, AL Taubman, BF Johnson, BJ Joseph, E Kucsera, TL Merrill, JT Morris, GA Hersey, S Forbes, G Newchurch, MJ Schmidlin, FJ Tarasick, DW Thouret, V Cammas, JP AF Thompson, Anne M. Stone, Jesse B. Witte, Jacquelyn C. Miller, Sonya K. Pierce, R. Bradley Chatfield, Robert B. Oltmans, Samuel J. Cooper, Owen R. Loucks, Amber L. Taubman, Brett F. Johnson, Bryan J. Joseph, Everette Kucsera, Tom L. Merrill, John T. Morris, Gary A. Hersey, Scott Forbes, Gerry Newchurch, Michael J. Schmidlin, F. J. Tarasick, David W. Thouret, Valerie Cammas, Jean-Pierre TI Intercontinental Chemical Transport Experiment Ozonesonde Network Study (IONS) 2004: 1. Summertime upper troposphere/lower stratosphere ozone over northeastern North America SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID AIR-MASS CHARACTERISTICS; AEROSOL DISTRIBUTIONS; LAMINATED STRUCTURE; BURNING SEASON; PROFILES; CLIMATOLOGY; POLLUTION; PACIFIC; BERMUDA; SONEX AB [1] Coordinated ozonesonde launches from the Intercontinental Transport Experiment (INTEX) Ozonesonde Network Study (IONS) (http://croc.gsfc.nasa.gov/intex/ions.html) in July-August 2004 provided nearly 300 O-3 profiles from eleven North American sites and the R/V Ronald H. Brown in the Gulf of Maine. With the IONS period dominated by low-pressure conditions over northeastern North America ( NENA), the free troposphere in that region was frequently enriched by stratospheric O-3. Stratospheric O-3 contributions to the NENA tropospheric O-3 budget are computed through analyses of O-3 laminae ( Pierce and Grant, 1998; Teitelbaum et al., 1996), tracers ( potential vorticity, water vapor), and trajectories. The lasting influence of stratospheric incursions into the troposphere is demonstrated, and the computed stratospheric contribution to tropospheric column O-3 over the R/V Ronald H. Brown and six sites in Michigan, Virginia, Maryland, Rhode Island, and Nova Scotia, 23% +/- 3%, is similar to summertime budgets derived from European O-3 profiles ( Collette and Ancellet, 2005). Analysis of potential vorticity, Wallops ozonesondes (37.9 degrees N, 75.5 degrees W), and Measurements of Ozone by Airbus Inservice Aircraft (MOZAIC) O-3 profiles for NENA airports in June-July-August 1996 2004 shows that the stratospheric fraction in 2004 may be typical. Boundary layer O-3 at Wallops and northeast U. S. sites during IONS also resembled O-3 climatology (June-July-August 1996 - 2003). However, statistical classification of Wallops O-3 profiles shows the frequency of profiles with background, nonpolluted boundary layer O-3 was greater than normal during IONS. C1 Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. Valparaiso Univ, Dept Phys & Astron, Valparaiso, IN 46383 USA. Univ Alabama, Dept Atmospher Sci, Huntsville, AL 35806 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. Environm Canada, Meteorol Serv Ctr, Toronto, ON M3H 5T4, Canada. NOAA, Earth Syst Res Lab, Boulder, CO 80305 USA. Howard Univ, Dept Phys & Astron, Washington, DC 20059 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Observ Midi Pyrenees, Ctr Natl Rech Sci, Lab Aerol, UMR 5560, F-31400 Toulouse, France. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Environm Canada Sable Isl, Dartmouth, NS B2Y 2N6, Canada. Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA. RP Thompson, AM (reprint author), Penn State Univ, Dept Meteorol, 503 Walker Bldg, University Pk, PA 16802 USA. EM witte@gavial.gsfc.nasa.gov; r.b.pierce@larc.nasa.gov; chatfield@clio.arc.nasa.gov; samuel.j.oltmans@noaa.gov; owen.r.cooper@noaa.gov; anne@met.psu.edu; bryan.johnson@noaa.gov; ejoseph@howard.edu; tlk@croc.gsfc.nasa.gov; jmerrill@gso.uri.edu; gmorris@valpo.edu; shersey@rice.edu; gerry.forbes@ec.gc.ca; mike@nsstc.uah.edu; fjs@osb1.wff.nasa.gov; david.tarasick@ec.gc.ca; thov@aero.obs-mip.fr; camjp@aero.obs-mip.fr RI Cooper, Owen/H-4875-2013; Pierce, Robert Bradley/F-5609-2010; Thompson, Anne /C-3649-2014; Manager, CSD Publications/B-2789-2015; OI Pierce, Robert Bradley/0000-0002-2767-1643; Thompson, Anne /0000-0002-7829-0920; Tarasick, David/0000-0001-9869-0692 NR 45 TC 57 Z9 57 U1 0 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 15 PY 2007 VL 112 IS D12 AR D12S12 DI 10.1029/2006JD007441 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 172XX UT WOS:000246839200001 ER PT J AU van Zadelhoff, GJ Heymsfield, AJ Donovan, DP McGill, MJ AF van Zadelhoff, G. -J. Heymsfield, A. J. Donovan, D. P. McGill, M. J. TI Evaluating lidar-radar microphysics retrieval using in situ measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ICE WATER-CONTENT; EFFECTIVE PARTICLE-SIZE; CRYSTAL-FACE; OPTICAL-PROPERTIES; CLOUD PROPERTIES; CIRRUS CLOUDS; ALGORITHMS; CALIPSO; MISSION AB [1] This study reports on a comparison between in situ and combined lidar and radar measurements of extinction and ice water content in ice clouds. The main goal of this exercise is to verify that the lidar-radar method can be confidently used for future satellite radar and lidar measurements. The data used in this study were obtained during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE) campaign that was conducted to study the properties of low-latitude, continentally influenced ice cloud layers. Two different methods are used to retrieve the extinction from the lidar signal. The comparison between lidar-derived and in situ - derived extinction values shows that they are strongly correlated for the two different lidar-based methods. Linear fits between the ice water contents derived from the two extinctions and radar reflectivity and the in situ values result in slope parameters of 0.93 +/- 0.28 and 1.09 +/- 0.35. The precise values depend on the assumed ice particle properties and particle size distribution used in the lidar-radar retrievals. C1 Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP van Zadelhoff, GJ (reprint author), Royal Netherlands Meteorol Inst, POB 201, NL-3730 AE De Bilt, Netherlands. EM zadelhof@knmi.nl RI McGill, Matthew/D-8176-2012; Heymsfield, Andrew/E-7340-2011; van Zadelhoff, Gerd-Jan/K-6283-2013 NR 24 TC 3 Z9 3 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 15 PY 2007 VL 112 IS D9 AR D09213 DI 10.1029/2006JD007202 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 172XR UT WOS:000246838600003 ER PT J AU Raj, SV Ghosn, LJ Lerch, BA Hebsur, M Cosgriff, LM Fedor, J AF Raj, S. V. Ghosn, L. J. Lerch, B. A. Hebsur, M. Cosgriff, L. M. Fedor, J. TI Mechanical properties of 17-4PH stainless steel foam panels SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE mechanical strength; 17-4PH stainless steel; sandwiched foams; fan blades AB Rectangular 17-4PH stainless steel sandwiched foam panels were fabricated using a commercial manufacturing technique by brazing two sheets to a foam core. Microstructural observations of the panels revealed large variations in the quality of the brazed areas from one panel to the next as well as within the same panel. Shear tests conducted on specimens machined from the panels exhibited failures either at poorly brazed face sheet-foam core interfaces or within foam cores of well-bonded specimens. Compression tests were conducted on the foam cores to evaluate their elastic and plastic deformation behavior. These data were compared with published data on polymeric and metallic foams, and with theoretical deformation models proposed for open cell foams. Published by Elsevier B.V. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Cleveland, OH 44135 USA. Cleveland State Univ, Cleveland, OH 44135 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. RP Raj, SV (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM sai.v.raj@nasa.gov NR 20 TC 20 Z9 21 U1 0 U2 8 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD MAY 15 PY 2007 VL 456 IS 1-2 BP 305 EP 316 DI 10.1016/j.msea.2006.11.142 PG 12 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 167YA UT WOS:000246487300042 ER PT J AU Gehrels, N AF Gehrels, Neil TI Swift observations of gamma-ray bursts SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article; Proceedings Paper CT Discussion Meeting on the Recent Developments in the Study of Gamma-Ray Bursts CY SEP 18-20, 2006 CL Royal Soc, London, ENGLAND HO Royal Soc DE gamma-ray bursts; high energy astrophysics; space astrophysics ID 28 FEBRUARY 1997; HOST GALAXY; AFTERGLOW; REDSHIFT; TELESCOPE; GRB-050709; SUPERNOVAE; EMISSION; GRB-060614; DISCOVERY AB Since its launch on 20 November 2004, the Swift mission has been detecting approximately 100 gamma-ray bursts (GRBs) each year, and immediately (within approx. 90 s) starting simultaneous X-ray and UV/optical observations of the afterglow. It has already collected an impressive database, including prompt emission to higher sensitivities than BATSE, uniform monitoring of afterglows and a rapid follow-up by other observatories notified through the GCN. Advances in our understanding of short GRBs have been spectacular. The detection of X-ray afterglows has led to accurate localizations and the conclusion that short GRBs can occur in non-star-forming galaxies or regions, whereas long GRBs are strongly concentrated within the star-forming regions. This is consistent with the NS merger model. Swift has greatly increased the redshift range of GRB detection. The highest redshift GRBs, at z similar to 5 6, are approaching the era of reionization. Ground-based deep optical spectroscopy of high redshift bursts is giving metallicity measurements and other information on the source environment to a much greater distance than other techniques. The localization of GRB 060218 to a nearby galaxy, and the association with SN 2006aj, added a valuable member to the class of GRBs with detected supernova. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gehrels, N (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM neil.gehrels@nasa.gov RI Gehrels, Neil/D-2971-2012 NR 40 TC 2 Z9 2 U1 0 U2 0 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-503X J9 PHILOS T R SOC A JI Philos. Trans. R. Soc. A-Math. Phys. Eng. Sci. PD MAY 15 PY 2007 VL 365 IS 1854 BP 1119 EP 1128 DI 10.1098/rsta.2006.1975 PG 10 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 150TD UT WOS:000245240400002 PM 17293335 ER PT J AU Burrows, DN Falcone, A Chincarini, G Morris, D Romano, P Hill, JE Godet, O Moretti, A Krimm, H Osborne, JP Racusin, J Mangano, V Page, K Perri, M Stroh, M AF Burrows, D. N. Falcone, A. Chincarini, G. Morris, D. Romano, P. Hill, J. E. Godet, O. Moretti, A. Krimm, H. Osborne, J. P. Racusin, J. Mangano, V. Page, K. Perri, M. Stroh, M. CA Swift XRT Team TI X-ray flares in early GRB afterglows SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article; Proceedings Paper CT Discussion Meeting on the Recent Developments in the Study of Gamma-Ray Bursts CY SEP 18-20, 2006 CL Royal Soc, London, ENGLAND HO Royal Soc DE gamma-ray bursts; gamma-ray burst afterglows; X-ray flares ID GAMMA-RAY; BURST AFTERGLOWS; ENGINE ACTIVITY; LIGHT-CURVE; TELESCOPE; EMISSION; GRB-050730; PRECURSOR; SPECTRA; MISSION AB The Swift X-ray Telescope (XRT) has discovered that flares are quite common in early X-ray afterglows of gamma-ray bursts (GRBs), being observed in roughly 50% of afterglows with prompt follow-up observations. The flares range influence from a few per cent to approximately 100% of the fluence of the prompt emission (the GRB). Repetitive flares are seen, with more than four successive flares detected by the XRT in some afterglows. The rise and fall times of the flares are typically considerably smaller than the time since the burst. These characteristics suggest that the flares are related to the prompt emission mechanism, but at lower photon energies. We conclude that the most likely cause of these flares is late-time activity of the GRB central engine. C1 Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Osservatorio Astrofis Brera, INAF, I-23807 Merate, Italy. Univ Milan, Dept Fis, I-20126 Milan, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Inst Astrofis Spaz & Fis Cosm, INAF, I-90146 Palermo, Italy. ASI Sci Data Ctr, I-00044 Frascati, Italy. RP Burrows, DN (reprint author), Penn State Univ, Dept Astron & Astrophys, 525 Davey Lab, University Pk, PA 16802 USA. EM dxb15@psu.edu RI Racusin, Judith/D-2935-2012; OI moretti, alberto/0000-0002-9770-0315; Perri, Matteo/0000-0003-3613-4409 NR 39 TC 34 Z9 34 U1 0 U2 0 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-503X J9 PHILOS T R SOC A JI Philos. Trans. R. Soc. A-Math. Phys. Eng. Sci. PD MAY 15 PY 2007 VL 365 IS 1854 BP 1213 EP 1226 DI 10.1098/rsta.2006.1970 PG 14 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 150TD UT WOS:000245240400013 PM 17293338 ER PT J AU Mason, KO Boyd, P Page, M Pandey, S Roming, P Schady, P AF Mason, Keith O. Boyd, Patricia Page, Mathew Pandey, Shashi Roming, Pete Schady, Patricia TI Optical/UV afterglows: Swift UVOT overview SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article; Proceedings Paper CT Discussion Meeting on the Recent Developments in the Study of Gamma-Ray Bursts CY SEP 18-20, 2006 CL Royal Soc, London, ENGLAND HO Royal Soc DE gamma rays : bursts; ISM : dust; extinction ID GAMMA-RAY BURSTS; GRB-050319 AB The ultraviolet and optical telescope (UVOT) on Swift provides coverage of gamma-ray bursts and their afterglows in the 170 650 nm band, yielding multiwavelength data of considerable diagnostic power in conjunction with the Swift X-ray Telescope. The results from the first eighteen months of operation show a broad range of afterglow behaviour, with considerably more complexity in many bursts than would be expected from the simple fireball model for the explosion. We briefly illustrate the capabilities of UVOT for measuring the evolution of nearby supernovae by reference to the observations of GRB 060218, and discuss the peculiar case of GRB 060614, which apparently resides in a nearby galaxy but which did not show the expected supernova feature in its light curve due to radioactive nickel decay. We discuss how the combination of X-ray and UV/optical spectral data can be used to investigate the environment of GRB host galaxies. C1 PPARC, Swindon SN2 1SZ, Wilts, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. UCL, Mullard Space Sci Lab, Dept Space & Climate Phys, Dorking RH5 6NT, Surrey, England. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. RP Mason, KO (reprint author), PPARC, Polaris House,N Star Ave, Swindon SN2 1SZ, Wilts, England. EM kom@mssl.ucl.ac.uk RI Boyd, Patricia/D-3274-2012 NR 18 TC 1 Z9 1 U1 0 U2 0 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-503X J9 PHILOS T R SOC A JI Philos. Trans. R. Soc. A-Math. Phys. Eng. Sci. PD MAY 15 PY 2007 VL 365 IS 1854 BP 1227 EP 1234 DI 10.1098/rsta.2006.1982 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 150TD UT WOS:000245240400014 PM 17293329 ER PT J AU van der Horst, AJ Kamble, A Wijers, RAMJ Resmi, L Bhattacharya, D Rol, E Strom, R Kouveliotou, C Oosterloo, T Ishwara-Chandra, CH AF van der Horst, A. J. Kamble, A. Wijers, R. A. M. J. Resmi, L. Bhattacharya, D. Rol, E. Strom, R. Kouveliotou, C. Oosterloo, T. Ishwara-Chandra, C. H. TI GRB 030329: 3 years of radio afterglow monitoring SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article; Proceedings Paper CT Discussion Meeting on the Recent Developments in the Study of Gamma-Ray Bursts CY SEP 18-20, 2006 CL Royal Soc, London, ENGLAND HO Royal Soc DE gamma-ray bursts; radio afterglows; afterglow modelling ID GAMMA-RAY BURST; CALORIMETRY; JET AB Radio observations of gamma-ray burst (GRB) afterglows are essential for our understanding of the physics of relativistic blast waves, as they enable us to follow the evolution of GRB explosions much longer than the afterglows in any other wave band. We have performed a 3-year monitoring campaign of GRB 030329 with the Westerbork Synthesis Radio Telescopes and the Giant Metrewave Radio Telescope. Our observations, combined with observations at other wavelengths, have allowed us to determine the GRB blast wave physical parameters, such as the total burst energy and the ambient medium density, as well as to investigate the jet nature of the relativistic outflow. Further, by modelling the late-time radio light curve of GRB 030329, we predict that the Low-Frequency Array (30 240 MHz) will be able to observe afterglows of similar GRBs, and constrain the physics of the blast wave during its non-relativistic phase. C1 Univ Amsterdam, Inst Astron, NL-1098 SJ Amsterdam, Netherlands. Raman Res Inst, Bangalore 560080, Karnataka, India. Indian Inst Sci, Joint Astron Programme, Bangalore 560012, Karnataka, India. Univ Leicester, Dept Phys & Astron, Leicester LE2 7RH, Leics, England. ASTRON, NL-7990 AA Dwingeloo, Netherlands. NASA, George C Marshall Space Flight Ctr, NSSTC, Huntsville, AL 35805 USA. Natl Ctr Radio Astrophys, Pune 411007, Maharashtra, India. RP van der Horst, AJ (reprint author), Univ Amsterdam, Inst Astron, Kruislaan 403, NL-1098 SJ Amsterdam, Netherlands. EM avdhorst@science.uva.nl RI Bhattacharya, Dipankar/J-6927-2015; OI Bhattacharya, Dipankar/0000-0003-3352-3142; Wijers, Ralph/0000-0002-3101-1808 NR 11 TC 3 Z9 3 U1 0 U2 0 PU ROYAL SOCIETY PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-503X J9 PHILOS T R SOC A JI Philos. Trans. R. Soc. A-Math. Phys. Eng. Sci. PD MAY 15 PY 2007 VL 365 IS 1854 BP 1241 EP 1246 DI 10.1098/rsta.2006.1993 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 150TD UT WOS:000245240400016 PM 17293318 ER PT J AU Barthelmy, SD AF Barthelmy, Scott D. TI Swift-BAT results on the prompt emission of short bursts SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article; Proceedings Paper CT Discussion Meeting on the Recent Developments in the Study of Gamma-Ray Bursts CY SEP 18-20, 2006 CL Royal Soc, London, ENGLAND HO Royal Soc DE gamma-ray burst; SHB; extended emission; long GRB ID GAMMA-RAY BURSTS AB This is a brief review of short hard bursts (SHBs) from previous missions and from Swift-BAT; in particular, a review of the developing class of gamma-ray bursts which are similar to SHBs in that they have the short hard initial spike (0.1 to a few seconds), but that they also have a long extended phase of soft emission (50 200 s). Further, we suggest that a class of events discovered by Horvath in the T90 versus hardness ratio plane is this SHB with extended emission. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Barthelmy, SD (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM scott@milkyway.gsfc.nasa.gov RI Barthelmy, Scott/D-2943-2012 NR 16 TC 3 Z9 3 U1 0 U2 0 PU ROYAL SOCIETY PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-503X J9 PHILOS T R SOC A JI Philos. Trans. R. Soc. A-Math. Phys. Eng. Sci. PD MAY 15 PY 2007 VL 365 IS 1854 BP 1281 EP 1291 DI 10.1098/rsta.2006.1967 PG 11 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 150TD UT WOS:000245240400023 PM 17293342 ER PT J AU Bennett, AF Lenski, RE AF Bennett, Albert F. Lenski, Richard E. TI An experimental test of evolutionary trade-offs during temperature adaptation SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article; Proceedings Paper CT Colloquium on In the Light of Evolution I CY DEC 01-02, 2006 CL Irvine, CA SP Natl Acad Sci, Arnold & Mabel Beckman Ctr DE bacteria; evolution; fitness ID ESCHERICHIA-COLI POPULATIONS; TERM EXPERIMENTAL EVOLUTION; ECOLOGICAL SPECIALIZATION; 20,000 GENERATIONS; GROWTH-RATE; ENVIRONMENT; SENESCENCE AB We used experimental evolution to test directly the important and commonplace evolutionary hypothesis that adaptation, increased fitness within the selective environment, is accompanied by trade-off, a loss of fitness in other nonselective environments. Specifically, we determined whether trade-offs at high temperature generally and necessarily accompany genetic adaptation to low temperature. We measured the relative fitness increment of 24 lineages of the bacterium Escherichia coli evolved for 2,000 generations at 20 degrees C and the relative fitness decrement of these lines at 40 degrees C. Trade-offs at the higher temperature were examined for their generality, universality, quantitative relationship, and historical contingency. Considering all 24 lines as a group, a significant decline in fitness was found at 40 degrees C (mean decline = 9.4%), indicating the generality of the trade-off effect. However, in a lineage-by-lineage analysis, only 15 of 24 showed a significant trade-off, and one lineage increased fitness at high temperature. Thus, although general, trade-offs were not universal. Furthermore, there was no quantitative association between the magnitude of adaptive fitness increment at 20 degrees C and fitness decline at 40 degrees C, and no effect of lineages' historical thermal environment on either their improvement at 20 degrees C or the extent of their trade-off at high temperature. We do not yet know the underlying mechanisms responsible for the trade-off, but they are sufficiently prevalent to drive a general effect. However, approximately one-third of the experimental lineages achieved low-temperature adaptation without detectable high-temperature trade-offs; therefore, it cannot be necessary that every change conferring benefit in cold environments has a negative effect on function in warmer environments. C1 Univ Calif Irvine, Dept Ecol & Evolutionary Biol, Irvine, CA 92697 USA. Michigan State Univ, Dept Microbiol & Mol Genet, E Lansing, MI 48824 USA. NASA, Astrobiol Inst, Moffett Field, CA 94035 USA. RP Bennett, AF (reprint author), Univ Calif Irvine, Dept Ecol & Evolutionary Biol, Irvine, CA 92697 USA. EM abennett@uci.edu OI Lenski, Richard/0000-0002-1064-8375 NR 28 TC 90 Z9 90 U1 4 U2 63 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 15 PY 2007 VL 104 SU 1 BP 8649 EP 8654 DI 10.1073/pnas.0702117104 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 170WV UT WOS:000246697800013 PM 17494741 ER PT J AU Riccardi, A Kump, LR Arthur, MA D'Hondt, S AF Riccardi, Anthony Kump, Lee R. Arthur, Michael A. D'Hondt, Steven TI Carbon isotopic evidence for chemocline upward excursions during the end-Permian event SO PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY LA English DT Article DE Permian; Triassic; mass extinction; carbon-isotope ID TRIASSIC SUPERANOXIC EVENT; MASS EXTINCTION; ORGANIC GEOCHEMISTRY; WESTERN SLOVENIA; EAST GREENLAND; OCEANIC ANOXIA; BOUNDARY; IMPACT; RELEASE; SULFUR AB A negative shift in marine inorganic carbon-isotope composition (delta C-13(carb)) during the end-Permian mass extinction has been used as evidence for several different extinction mechanisms. Changes to the delta C-13 of organic matter and the difference between it and delta C-13(carb) (Delta C-13=delta C-13(carb) - delta C-13(org)) have been examined at few locations, with conflicting interpretations. We examine the changes to both organic and inorganic carbon isotopes across the Permian-Triassic boundary at two marine sections from South China (Meishan and Shangsi) and compare these to data from other previously published sections. Through these analyses, we demonstrate that a decrease in Delta C-13 occurred during the extinction event throughout the Paleo-Tethys ocean. The extent and intensity of the decrease varies by location averaging a negative shift of - 5 parts per thousand. Several possibilities as to the cause of this shift exist including Siberian trap volcanism, a change in the terrestrial/marine organic carbon input to the system, or a change in the dominant marine biota brought about through environmental changes (such as widespread ocean anoxia/euxinia). The decrease in Delta C-13 observed at many of these sections across the event horizon is here interpreted to represent a shift from algae/cyanobacteria to less fractionating phototrophic sulfur bacteria in marine shelf environments resulting from upward excursions of the chemocline. These chemocline upward excursions would release euxinic water to the photic, zone allowing phototrophic sulfur bacteria to thrive. The limited available biomarker data are consistent with this interpretation. (C) 2006 Elsevier B.V. All rights reserved. C1 Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. Penn State Univ, NASA, Astrobiol Inst, University Pk, PA 16802 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. Univ Rhode Isl, NASA, Astrobiol Inst, Narragansett, RI 02882 USA. RP Riccardi, A (reprint author), Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. EM ariccard@geosc.psu.edu RI Kump, Lee/H-8287-2012; Arthur, Michael/E-2872-2014 OI Arthur, Michael/0000-0002-3028-6279 NR 44 TC 73 Z9 80 U1 1 U2 23 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-0182 J9 PALAEOGEOGR PALAEOCL JI Paleogeogr. Paleoclimatol. Paleoecol. PD MAY 14 PY 2007 VL 248 IS 1-2 BP 73 EP 81 DI 10.1016/j.palaeo.2006.11.010 PG 9 WC Geography, Physical; Geosciences, Multidisciplinary; Paleontology SC Physical Geography; Geology; Paleontology GA 169AF UT WOS:000246564400006 ER PT J AU Zurek, RW Smrekar, SE AF Zurek, Richard W. Smrekar, Suzanne E. TI An overview of the Mars Reconnaissance Orbiter (MRO) science mission SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID ATMOSPHERE; SUBSURFACE; SURFACE; CLIMATE AB The Mars Reconnaissance Orbiter ( MRO) is the latest addition to the suite of missions on or orbiting Mars as part of the NASA Mars Exploration Program. Launched on 12 August 2005, the orbiter successfully entered Mars orbit on 10 March 2006 and finished aerobraking on 30 August 2006. Now in its near- polar, near- circular, low-altitude ( similar to 300 km), 3 p.m. orbit, the spacecraft is operating its payload of six scientific instruments throughout a one-Mars-year Primary Science Phase ( PSP) of global mapping, regional survey, and targeted observations. Eight scientific investigations were chosen for MRO, two of which use either the spacecraft accelerometers or tracking of the spacecraft telecom signal to acquire data needed for analysis. Six instruments, including three imaging systems, a visible-near infrared spectrometer, a shallow-probing subsurface radar, and a thermal-infrared profiler, were selected to complement and extend the capabilities of current working spacecraft at Mars. Whether observing the atmosphere, surface, or subsurface, the MRO instruments are designed to achieve significantly higher resolution while maintaining coverage comparable to the current best observations. The requirements to return higher-resolution data, to target routinely from a low-altitude orbit, and to operate a complex suite of instruments were major challenges successfully met in the design and build of the spacecraft, as well as by the mission design. Calibration activities during the seven-month cruise to Mars and limited payload operations during a three-day checkout prior to the start of aerobraking demonstrated, where possible, that the spacecraft and payload still had the functions critical to the science mission. Two critical events, the deployment of the SHARAD radar antenna and the opening of the CRISM telescope cover, were successfully accomplished in September 2006. Normal data collection began 7 November 2006 after solar conjunction. As part of its science mission, MRO will also aid identification and characterization of the most promising sites for future landed missions, both in terms of safety and in terms of the scientific potential for future discovery. Ultimately, MRO data will advance our understanding of how Mars has evolved and by which processes that change occurs, all within a framework of identifying the presence, extent, and role of water in shaping the planet's climate over time. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zurek, RW (reprint author), CALTECH, Jet Prop Lab, Mail Stop 264-535,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM richard.w.zurek@jpl.nasa.gov; ssmrekar@jpl.nasa.gov NR 26 TC 68 Z9 68 U1 2 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 12 PY 2007 VL 112 IS E5 AR E05S01 DI 10.1029/2006JE002701 PG 22 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 168BP UT WOS:000246497600002 ER PT J AU Williams, KE Toon, OB Heldmann, J AF Williams, K. E. Toon, O. B. Heldmann, J. TI Modeling water ice lifetimes at recent Martian gully locations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LIQUID WATER; MARS AB Mars Global Surveyor identified two instances of recent changes in gully morphology. Images suggest that two gullies had recent discharges of some liquid, leaving a residue behind. The residue might be water ice mixed with dust. We applied a thermodynamic model to these two locations to determine the lifetime of the hypothetical water ice. We find that a very dusty 2m-thick icepack of moderate density would completely disappear within 1 - 2 Mars years by sublimation. If the bright deposits are actually ice then we would expect to see them absent in images taken several Mars years from now, unless they are being replenished. C1 Univ Colorado, LASP, Dept Atmospher & Ocean Sci, Boulder, CO 80309 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Williams, KE (reprint author), Univ Colorado, LASP, Dept Atmospher & Ocean Sci, UCB 392, Boulder, CO 80309 USA. EM kaj.williams@colorado.edu NR 6 TC 4 Z9 4 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 11 PY 2007 VL 34 IS 9 AR L09204 DI 10.1029/2007GL029507 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 168AJ UT WOS:000246494000001 ER PT J AU Liang, Q Jaegle, L Hudman, RC Turquety, S Jacob, DJ Avery, MA Browell, EV Sachse, GW Blake, DR Brune, W Ren, X Cohen, RC Dibb, JE Fried, A Fuelberg, H Porter, M Heikes, BG Huey, G Singh, HB Wennberg, PO AF Liang, Q. Jaegle, L. Hudman, R. C. Turquety, S. Jacob, D. J. Avery, M. A. Browell, E. V. Sachse, G. W. Blake, D. R. Brune, W. Ren, X. Cohen, R. C. Dibb, J. E. Fried, A. Fuelberg, H. Porter, M. Heikes, B. G. Huey, G. Singh, H. B. Wennberg, P. O. TI Summertime influence of Asian pollution in the free troposphere over North America SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review ID PACIFIC TRACE-P; BIOMASS BURNING EMISSIONS; LONG-RANGE TRANSPORT; PEM-WEST-B; UNITED-STATES; AIR-POLLUTION; CONTINENTAL OUTFLOW; PRINCIPAL COMPONENT; CHEMICAL EVOLUTION; MOPITT INSTRUMENT AB [1] We analyze aircraft observations obtained during INTEX-A ( 1 July to 14 August 2004) to examine the summertime influence of Asian pollution in the free troposphere over North America. By applying correlation analysis and principal component analysis (PCA) to the observations between 6 and 12 km, we find dominant influences from recent convection and lightning (13% of observations), Asia (7%), the lower stratosphere ( 7%), and boreal forest fires (2%), with the remaining 71% assigned to background. Asian air masses are marked by high levels of CO, O-3, HCN, PAN, C2H2, C6H6, methanol, and SO42-. The partitioning of NOy species in the Asian plumes is dominated by PAN ( similar to 600 pptv), with varying NOx/HNO3 ratios in individual plumes, consistent with individual transit times of 3 - 9 days. Export of Asian pollution occurred in warm conveyor belts of midlatitude cyclones, deep convection, and in typhoons. Compared to Asian outflow measurements during spring, INTEX-A observations display lower levels of anthropogenic pollutants (CO, C3H8, C2H6, C6H6) due to shorter summer lifetimes; higher levels of biogenic tracers ( methanol and acetone) because of a more active biosphere; and higher levels of PAN, NOx, HNO3, and O-3 reflecting active photochemistry, possibly enhanced by efficient NOy export and lightning. The high Delta O-3/Delta CO ratio (0.76 mol/mol) in Asian plumes during INTEX-A is due to strong photochemical production and, in some cases, mixing with stratospheric air along isentropic surfaces. The GEOS-Chem global model captures the timing and location of the Asian plumes. However, it significantly underestimates the magnitude of observed enhancements in CO, O-3, PAN and NOx. C1 Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ New Hampshire, Climate Change Res Ctr, Durham, NH 03824 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. Univ Rhode Isl, Dept Oceanog, Narragansett, RI 02881 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. CALTECH, Pasadena, CA 91125 USA. RP Liang, Q (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt Rd, Greenbelt, MD 20771 USA. EM liang@code916.gsfc.nasa.gov; jaegle@atmos.washington.edu; hudman@fas.harvard.edu; turquety@aero.jussieu.fr; djacob@fas.harvard.edu; melody.a.avery@nasa.gov; e.v.browell@larc.nasa.gov; g.w.sachse@larc.nasa.gov; drblake@uci.edu; brune@ems.psu.edu; ren@essc.psu.edu; cohen@cchem.berkeley.edu; jack.dibb@unh.edu; fried@ucar.edu; fuelberg@met.fsu.edu; mporter@met.fsu.edu; bheikes@gsu.uri.edu; greg.huey@eas.gatech.edu; hanwant.b.singh@nasa.gov; wennberg@gps.caltech.edu RI Cohen, Ronald/A-8842-2011; Liang, Qing/B-1276-2011; Ren, Xinrong/B-2229-2010; Hudman, Rynda/C-6118-2009; Wennberg, Paul/A-5460-2012; Chem, GEOS/C-5595-2014; Ren, Xinrong/E-7838-2015 OI Cohen, Ronald/0000-0001-6617-7691; Ren, Xinrong/0000-0001-9974-1666 NR 112 TC 49 Z9 49 U1 0 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 11 PY 2007 VL 112 IS D12 AR D12S11 DI 10.1029/2006JD007919 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 168AY UT WOS:000246495700001 ER PT J AU Mach, DM Christian, HJ Blakeslee, RJ Boccippio, DJ Goodman, SJ Boeck, WL AF Mach, Douglas M. Christian, Hugh J. Blakeslee, Richard J. Boccippio, Dennis J. Goodman, Steven J. Boeck, William L. TI Performance assessment of the Optical Transient Detector and Lightning Imaging Sensor SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID FLORIDA THUNDERSTORMS; STORM; OTD AB We describe the clustering algorithm used by the Lightning Imaging Sensor ( LIS) and the Optical Transient Detector ( OTD) for combining the space-based observations of lightning pulse data into events, groups, flashes, and areas. Events are single pixels that exceed the LIS/OTD background level during a single frame ( 2 ms). Groups are clusters of events that occur within the same frame and in adjacent pixels. Flashes are clusters of groups that occur within 330 ms and either 5.5 km ( for LIS) or 16.5 km ( for OTD) of each other. Areas are clusters of flashes that occur within 16.5 km of each other. The flash data from LIS/ OTD are currently being used for lightning and thunderstorm processes and climatological studies; therefore we test how variations in the algorithms for the event-group and group-flash clustering affect the flash count for a subset of the LIS and OTD data. We divided the subset into areas with low ( 1-3), medium ( 4-15), high ( 16-63), and very high ( 64+) flash counts to see how changes in the clustering parameters affect the flash rates in these different sizes of areas. We found that as long as the cluster parameters are within about a factor of two of the current values, the overall flash counts do not change by more than about 20%. Therefore the flash clustering algorithm used by the LIS and OTD sensors are robust and create flash rates that are relatively insensitive to reasonable variations in the clustering algorithms. C1 Univ Alabama, Global Hydrol & Climate Ctr, Huntsville, AL 35899 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. Niagara Univ, Niagara Falls, NY 14109 USA. RP Mach, DM (reprint author), Univ Alabama, Global Hydrol & Climate Ctr, 320 Sparkman Dr,Room 4001, Huntsville, AL 35899 USA. EM dmach@nasa.gov NR 20 TC 46 Z9 46 U1 0 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 11 PY 2007 VL 112 IS D9 AR D09210 DI 10.1029/2006JD007787 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 168AR UT WOS:000246494900003 ER PT J AU Martin, RV Sauvage, B Folkins, I Sioris, CE Boone, C Bernath, P Ziemke, J AF Martin, Randall V. Sauvage, Bastien Folkins, Ian Sioris, Christopher E. Boone, Christopher Bernath, Peter Ziemke, Jerry TI Space-based constraints on the production of nitric oxide by lightning SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review ID TROPICAL TROPOSPHERIC OZONE; OPTICAL TRANSIENT DETECTOR; UNITED-STATES; SATELLITE-OBSERVATIONS; ATMOSPHERIC CHEMISTRY; MAPPING SPECTROMETER; NOX PRODUCTION; MONITORING INSTRUMENT; AIRCRAFT MEASUREMENTS; GLOBAL DISTRIBUTION AB We interpret observations of trace-gases from three satellite platforms to provide top-down constraints on the production of NO by lightning. The space-based observations are tropospheric NO2 columns from SCIAMACHY, tropospheric O-3 columns from OMI and MLS, and upper tropospheric HNO3 from ACE-FTS. A global chemical transport model ( GEOS-Chem) is used to identify locations and time periods in which lightning would be expected to dominate the trace gas observations. The satellite observations are sampled at those locations and time periods. All three observations exhibit a maximum in the tropical Atlantic region and a minimum in the tropical Pacific. This wave-1 pattern is driven by injection of lightning NO into the upper troposphere over the tropical continents, followed by photochemical production of NO2, HNO3, and O-3 during transport. Lightning produces a broad enhancement over the tropical Atlantic and Africa of 2-6 x 10(14) molecules NO2 cm(-2), 4 x 10(17) molecules O-3 cm(-2) ( 15 Dobson Units), and 125 pptv of upper tropospheric HNO3. The lightning background is 25-50% weaker over the tropical Pacific. A global source of 6 +/- 2 Tg N yr(-1) from lightning in the model best represents the satellite observations of tropospheric NO2, O-3, and HNO3. C1 Dalhousie Univ, Dept Phys & Atmospher Sci, Halifax, NS B3H 3J5, Canada. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Saskatchewan, Dept Phys & Engn, Saskatoon, SK B3H 3J5, Canada. Univ Waterloo, Dept Chem, Waterloo, ON N2L 3G1, Canada. Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Martin, RV (reprint author), Dalhousie Univ, Dept Phys & Atmospher Sci, Halifax, NS B3H 3J5, Canada. EM randall.martin@dal.ca RI Martin, Randall/A-2051-2008; Bernath, Peter/B-6567-2012; Martin, Randall/C-1205-2014; Chem, GEOS/C-5595-2014; OI Bernath, Peter/0000-0002-1255-396X; Martin, Randall/0000-0003-2632-8402; Sioris, Christopher/0000-0003-1168-8755 NR 104 TC 108 Z9 110 U1 1 U2 33 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 11 PY 2007 VL 112 IS D9 AR D09309 DI 10.1029/2006JD007831 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 168AR UT WOS:000246494900005 ER PT J AU Sievers, JL Achermann, C Bond, JR Bronfman, L Bustos, R Contaldi, CR Dickinson, C Ferreira, PG Jones, ME Lewis, AM Mason, BS May, J Myers, ST Oyarce, N Padin, S Pearson, TJ Pospieszalski, M Readhead, ACS Reeves, R Taylor, AC Torres, S AF Sievers, J. L. Achermann, C. Bond, J. R. Bronfman, L. Bustos, R. Contaldi, C. R. Dickinson, C. Ferreira, P. G. Jones, M. E. Lewis, A. M. Mason, B. S. May, J. Myers, S. T. Oyarce, N. Padin, S. Pearson, T. J. Pospieszalski, M. Readhead, A. C. S. Reeves, R. Taylor, A. C. Torres, S. TI Implications of the cosmic background imager polarization data SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; polarization ID PROBE WMAP OBSERVATIONS; 2003 FLIGHT; COSMOLOGICAL PARAMETERS; POWER SPECTRUM; MOSAIC OBSERVATIONS; ANISOTROPY; BOOMERANG; RADIATION; FLUCTUATIONS; DASI AB We present new measurements of the power spectra of the E mode of cosmic microwave background (CMB) polarization, the temperature T, the cross-correlation of E and T, and upper limits on the B mode from 2.5 yr of dedicated Cosmic Background Imager (CBI) observations. Both raw maps and optimal signal images in the (u, v)plane and the sky plane show strong detections of the E mode (11.7 sigma for the EE power spectrum overall) and no detection of the B mode. The power spectra are used to constrain parameters of the flat tilted adiabatic Lambda CDM models: those determined from EE and TE bandpowers agree with those from TT, which is a powerful consistency check. There is little tolerance for shifting polarization peaks from the TT-forecast locations, as measured by the angular sound crossing scale theta = 100/ ls = 1.03 +/- 0.02 from EE and TE; compare with 1.044 +/- 0: 005 with the TT data included. The scope for extra out- of- phase peaks from subdominant isocurvature modes is also curtailed. The EE and TE measurements of CBI, DASI, and BOOMERANG are mutually consistent and, taken together rather than singly, give enhanced leverage for these tests. C1 Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 1A1, Canada. Univ Concepcion, Dept Ingn Elect, Concepcion, Chile. Univ Chile, Dept Astron, Santiago, Chile. Univ London Imperial Coll Sci & Technol, Dept Phys, London, England. CALTECH, Chajnantor Observ, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Oxford, Oxford, England. Natl Radio Astron Observ, Green Bank, WV USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Univ Chicago, Kavli Inst Cosmol Phys, Dept Astron & Astrophys, Chicago, IL 60637 USA. Natl Radio Astron Observ, Charlottesville, VA USA. RP Sievers, JL (reprint author), Univ Toronto, Canadian Inst Theoret Astrophys, 60 St George St, Toronto, ON M5S 1A1, Canada. RI Bronfman, Leonardo/H-9544-2013; Reeves, Rodrigo/H-2812-2014; Optica y Fotonica, Centro/I-4347-2015; Pearson, Timothy/N-2376-2015; OI Bronfman, Leonardo/0000-0002-9574-8454; Reeves, Rodrigo/0000-0001-5704-271X; Pearson, Timothy/0000-0001-5213-6231; Sievers, Jonathan/0000-0001-6903-5074 NR 30 TC 86 Z9 86 U1 1 U2 8 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2007 VL 660 IS 2 BP 976 EP 987 DI 10.1086/510504 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169CW UT WOS:000246571300005 ER PT J AU Temi, P Brighenti, F Mathews, WG AF Temi, Pasquale Brighenti, Fabrizio Mathews, William G. TI Far-infrared Spitzer observations of elliptical galaxies: Evidence for extended diffuse dust SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : elliptical and lenticular, cD; galaxies : ISM; infrared : galaxies; infrared : ISM ID SPECTRAL ENERGY-DISTRIBUTIONS; X-RAY-EMISSION; IONIZED-GAS; INTERSTELLAR MATTER; HOT GAS; STELLAR POPULATIONS; SPACE-TELESCOPE; CHANDRA OBSERVATIONS; LENTICULAR GALAXIES; SIZE DISTRIBUTION AB Far-infrared Spitzer observations of elliptical galaxies are inconsistent with simple steady state models of dust creation in red giant stars and destruction by grain sputtering in the hot interstellar gas at T - 10(7) K. The flux at 24 mu m correlates with optical fluxes, suggesting that this relatively hot dust is largely circumstellar. But fluxes at 70 and 160 mu m do not correlate with optical fluxes. Elliptical galaxies with similar LB have luminosities at 70 and 160 mu m( L-70 and L-160) that vary over a factor of - 100, implying an additional source of dust unrelated to that produced by ongoing local stellar mass loss. Neither L-70/ LB nor L-160/ LB correlate with the stellar age or metallicity. Optical line fluxes from warm gas at T - 10(4) K correlate weakly with L-70 and L-160, suggesting that the dust may be responsible for cooling this gas. Many normal elliptical galaxies have emission at 70 mu m that is extended to 5-10 kpc. Extended far-infrared emission with sputtering lifetimes of - 10(8) yr is difficult to maintain by mergers with gas-rich galaxies. Instead, we propose that this cold dust is buoyantly transported from reservoirs of dust in the galactic cores, which are supplied by mass loss from stars in the core. Intermittent energy outbursts from AGNs can drive the buoyant outflow. C1 NASA, Ames Res Ctr, Astrophys Branch, Moffett Field, CA 94035 USA. SETI Inst, Mountain View, CA 94043 USA. Univ Western Ontario, Dept Phys & Astron, London, ON N6A 3K7, Canada. Univ Calif Santa Cruz, Lick Observ, Board Studies Astron & Astrophys, Univ Calif Observ, Santa Cruz, CA 95064 USA. Univ Bologna, Dipartimento Astron, I-40127 Bologna, Italy. RP Temi, P (reprint author), NASA, Ames Res Ctr, Astrophys Branch, MS 245-6, Moffett Field, CA 94035 USA. NR 88 TC 73 Z9 74 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2007 VL 660 IS 2 BP 1215 EP 1231 DI 10.1086/513690 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169CW UT WOS:000246571300027 ER PT J AU Guiles, S Bernard-Salas, J Pottasch, SR Roellig, TL AF Guiles, S. Bernard-Salas, J. Pottasch, S. R. Roellig, T. L. TI The Spitzer IRS infrared spectrum and abundances of the planetary nebula IC 2448 SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : general; ISM : abundances; ISM : lines and bands; planetary nebulae : individual (IC 2448); stars : AGB and post-AGB ID ASYMPTOTIC GIANT BRANCH; SPACE-TELESCOPE; CENTRAL STARS; ELEMENTAL ABUNDANCES; ARGON ABUNDANCES; SOUTHERN SAMPLE; EVOLUTION; CHLORINE; SULFUR; SPECTROGRAPH AB We present the mid-infrared spectrum of the planetary nebula IC 2448. In order to determine the chemical composition of the nebula, we use the infrared line fluxes from the Spitzer spectrum along with optical line fluxes from the literature and ultraviolet line fluxes from archival IUE spectra. We determine an extinction of C H beta = 0. 27 from hydrogen recombination lines and the radio to H beta ratio. Forbidden line ratios give an electron density of 1860 cm (-3) and an average electron temperature of 12,700 K. The use of infrared lines allows us to determine more accurate abundances than previously possible because abundances derived from infrared lines do not vary greatly with the adopted electron temperature and extinction, and additional ionization stages are observed. Elements left mostly unchanged by stellar evolution ( Ar, Ne, S, and O) all have subsolar values in IC 2448, indicating that the progenitor star formed out of moderately metal deficient material. Evidence from the Spitzer spectrum of IC 2448 supports previous claims that IC 2448 is an old nebula formed from a low-mass progenitor star. C1 Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. Univ Groningen, Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Guiles, S (reprint author), Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. EM sg283@cornell.edu; jbs@isc.astro.cornell.edu; pottasch@astro.rug.nl; thomas.l.roellig@nasa.gov NR 36 TC 10 Z9 10 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2007 VL 660 IS 2 BP 1282 EP 1288 DI 10.1086/513692 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169CW UT WOS:000246571300032 ER PT J AU Close, LM Zuckerman, B Song, I Barman, T Marois, C Rice, EL Siegler, N Macintosh, B Becklin, EE Campbell, R Lyke, JE Conrad, A Le Mignant, D AF Close, Laird M. Zuckerman, B. Song, Inseok Barman, Travis Marois, Christian Rice, Emily L. Siegler, Nick Macintosh, Bruce Becklin, E. E. Campbell, Randy Lyke, James E. Conrad, Al Le Mignant, David TI The wide brown dwarf binary Oph 1622-2405 and discovery of a wide, low-mass binary in Ophiuchus (Oph 1623-2402): A new class of young evaporating wide binaries? SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : general; instrumentation : adaptive optics; stars : evolution; stars : formation; stars : individual (2MASS J16222521-2405139, 2MASS J16233609-2402209); stars : low-mass, brown dwarfs ID ADAPTIVE OPTICS SURVEY; NEAR-INFRARED SPECTRA; UPPER-SCORPIUS; EVOLUTIONARY MODELS; SOLAR NEIGHBORHOOD; ULTRACOOL DWARFS; M6.0-M7.5 STARS; OB ASSOCIATION; 30 MYR; TELESCOPE AB We imaged five objects near the star-forming clouds of Ophiuchus with the Keck Laser Guide Star AO system. We resolved sources 11 ( Oph 16222 - 2405) and 16 ( Oph 16233 - 2402) from Allers and coworkers into binary systems. Source 11 is resolved into a 243 AU binary, the widest known for a very low mass (VLM) binary. The binary nature of source 11 was discovered first by Allers and independently here, during which we obtained the first spatially resolved R - 2000 near-infrared ( J and K) spectra, mid-IR photometry, and orbital motion estimates. We estimate for 11A and 11B gravities ( log g > 3.75), ages ( 5 +/- 2 Myr), luminosities [ log ( L/ L circle dot )= -2: 77 +/- 0.10 and -2. 96 +/- 0.10], and temperatures ( T-eff = 2375 +/- 175 K and 2175 +/- 175 K). We find self-consistent DUSTY evolutionary model ( Chabrier and coworkers) masses of 17(-5)(+4) 5 MJ and 14(-5)(+6) 5 MJ, for 11A and 11B, respectively. Our masses are higher than those previously reported ( 13-15 MJ and 7-8 MJ) by Jayawardhana & Ivanov. Hence, we find that the system is unlikely a "planetary mass binary,'' as do Luhman and coworkers, but it has the second lowest mass and lowest binding energy of any known binary. Oph 11 and Oph 16 belong to a newly recognized population of wide ( greater than or similar to 100 AU), young (< 10 Myr), roughly equal mass, VLM stellar and brown dwarf binaries. We deduce that - 6% +/- 3% of young (< 10 Myr) VLM objects are in such wide systems. However, only 0. 3% +/- 0.1% of old field VLM objects are found in such wide systems. Thus, young, wide, VLM binary populations may be evaporating, due to stellar encounters in their natal clusters, leading to a field population depleted in wide VLM systems. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, NASA, Astrobiol Inst, Los Angeles, CA 90095 USA. Gemini Observ, Hilo, HI 96720 USA. Lowell Observ, Flagstaff, AZ 86001 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. WM Keck Observ, Kamuela, HI 96743 USA. RP Close, LM (reprint author), Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. EM lclose@as.arizona.edu RI Rice, Emily/G-4446-2013 OI Rice, Emily/0000-0002-3252-5886 NR 74 TC 56 Z9 56 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2007 VL 660 IS 2 BP 1492 EP 1506 DI 10.1086/513417 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169CW UT WOS:000246571300054 ER PT J AU Rhee, JH Song, I Zuckerman, B McElwain, M AF Rhee, Joseph H. Song, Inseok Zuckerman, B. McElwain, Michael TI Characterization of dusty debris disks: The IRAS and Hipparcos catalogs SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; planetary systems : protoplanetary disks ID VEGA-LIKE STARS; TERRESTRIAL PLANET FORMATION; SPITZER-SPACE-TELESCOPE; TW HYDRAE ASSOCIATION; MAIN-SEQUENCE STARS; SOLAR-TYPE STARS; YOUNG STARS; AGE-DEPENDENCE; EVOLUTION; NEARBY AB Dusty debris disks around main-sequence stars are signposts for the existence of planetesimals and exoplanets. From cross-correlating Hipparcos stars with the IRAS catalogs, we identify 146 stars within 120 pc of Earth that show excess emission at 60 mu m. This search took special precautions to avoid false positives. Our sample is reasonably well distributed from late B to early K-type stars, but it contains very few later type stars. Even though IRAS flew more than 20 years ago and many astronomers have cross-correlated its catalogs with stellar catalogs, we were still able to newly identify debris disks at as many as 33 main-sequence stars; of these, 32 are within 100 pc of Earth. The power of an all-sky survey satellite like IRAS is evident when comparing our 33 new debris disks with the total of only 22 dusty debris disk stars first detected with the more sensitive, but pointed, satellite ISO. Our investigation focuses on the mass, dimensions, and evolution of dusty debris disks. C1 Gemini Observ, Hilo, HI 96720 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, NASA, Astrobiol Inst, Los Angeles, CA 90095 USA. RP Rhee, JH (reprint author), Gemini Observ, Hilo, HI 96720 USA. EM jrhee@gemini.edu; song@gemini.edu; ben@astro.ucla.edu; mcelwain@astro.ucla.edu RI McElwain, Michael/D-3607-2012 OI McElwain, Michael/0000-0003-0241-8956 NR 58 TC 148 Z9 148 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2007 VL 660 IS 2 BP 1556 EP 1571 DI 10.1086/509912 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169CW UT WOS:000246571300059 ER PT J AU Davis, SS AF Davis, Sanford S. TI ICE formation in radiated accretion disks SO ASTROPHYSICAL JOURNAL LA English DT Article DE planetary systems : formation; planetary systems : protoplanetary disks ID PROTOPLANETARY DISKS; CIRCUMSTELLAR DISKS; T-TAURI; DISTRIBUTIONS; STARS; DUST; DESTRUCTION; MOLECULES; EVOLUTION; MODELS AB Gas to solid phase changes of abundant species in a viscous, irradiated protoplanetary disk are investigated using a new formulation for the freezeout effect. The method is based on a procedure using species-dependent phase diagrams while following the chemical evolution of water and carbon monoxide gas until their partial pressures are sufficient to de-sublimate vapor into ice. It is found that water ice is dominant throughout the nebula while a significant amount of water vapor coexists with the ice in the cooler parts of the inner nebula. Volatile CO molecules de-sublimate only in the colder outer regions of the nebula near the center plane. Computed column densities for CO gas are compared with similar calculations using an adsorption/desorption model by Aikawa and Herbst and are shown to predict similar distributions. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Davis, SS (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM sdavis@mail.arc.nasa.gov NR 18 TC 6 Z9 6 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2007 VL 660 IS 2 BP 1580 EP 1587 DI 10.1086/513591 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169CW UT WOS:000246571300061 ER PT J AU McIntosh, SW Leamon, RJ Davey, AR Wills-Davey, MJ AF McIntosh, Scott W. Leamon, Robert J. Davey, Alisdair R. Wills-Davey, Meredith J. TI The posteruptive evolution of a coronal dimming SO ASTROPHYSICAL JOURNAL LA English DT Article DE solar wind; Sun : corona; Sun : coronal mass ejections (CMEs); Sun : granulation; Sun : magnetic fields; Sun : transition region; Sun : UV radiation ID TRANSITION REGION MOSS; MASS EJECTION; MAGNETIC RECONNECTION; DYNAMIC FIBRILS; ORIGIN; FLUX; RESOLUTION; VELOCITY AB We discuss the posteruptive evolution of a " coronal dimming'' based on observations of the EUV corona from the Solar and Heliospheric Observatory and the Transition Region and Coronal Explorer ( TRACE). This discussion highlights the roles played by magnetoconvection- driven magnetic reconnection and the global magnetic environment of the plasma in the " filling'' and apparent motion of the region following the eruption of a coronal mass ejection ( CME). A crucial element in our understanding of the dimming region's evolution is developed by monitoring the disappearance and reappearance of bright TRACE " moss'' around the active region that gives rise to the CME. We interpret the change in the TRACE moss as a proxy of the changing coronal magnetic field topology behind the CME front. We infer that the change in the global magnetic topology also results in a shift of the energy balance in the process responsible for the production of the moss emission while the coronal magnetic topology evolves from closed to open and back to closed again because, following the eruption, the moss reforms around the active region in almost exactly its pre-event configuration. As a result of the moss's evolution, combining our discussion with recent spectroscopic results of an equatorial coronal hole, we suggest that the interchangeable use of the term "transient coronal hole'' to describe a coronal dimming is more than just a simple coincidence. C1 SW Res Inst, Dept Space Studies, Boulder, CO 80302 USA. NASA, Goddard Space Flight Ctr, ADNET Syst Inc, Greenbelt, MD 20771 USA. RP McIntosh, SW (reprint author), SW Res Inst, Dept Space Studies, Boulder, CO 80302 USA. EM mcintosh@boulder.swri.edu NR 28 TC 26 Z9 26 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2007 VL 660 IS 2 BP 1653 EP 1659 DI 10.1086/512665 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169CW UT WOS:000246571300067 ER PT J AU Eriksen, HK Banday, AJ Gorski, KM Hansen, FK Lilje, PB AF Eriksen, H. K. Banday, A. J. Gorski, K. M. Hansen, F. K. Lilje, P. B. TI Hemispherical power asymmetry in the third-year Wilkinson Microwave Anisotropy Probe sky maps SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; methods : statistical ID WMAP; SPECTRUM; ISOTROPY; SPOT AB We consider the issue of hemispherical power asymmetry in the third-year WMAP data, adopting a previously introduced modulation framework. Computing both frequentist probabilities and Bayesian evidences, we find that the model consisting of an isotropic CMB sky modulated by a dipole field gives a substantially better fit to the observations than the purely isotropic model, even when accounting for the larger prior volume. For the ILC map, the Bayesian log-evidence difference is similar to 1.8 in favor of the modulated model, and the raw improvement in maximum log likelihood is 6.1. The best-fit modulation dipole axis points toward ( l, b) p ( 225 degrees, -27 degrees), and the modulation amplitude is 0.114, in excellent agreement with the results from the first-year analyses. The frequentist probability of obtaining such a high modulation amplitude in an isotropic universe is similar to 1%. These results are not sensitive to data set or sky cut. Thus, the statistical evidence for a power asymmetry anomaly is both substantial and robust, although not decisive, for the currently available data. Increased sky coverage through better foreground handling and full-sky and high-sensitivity polarization maps may shed further light on this issue. C1 Univ Oslo, Inst Theoret Astrophys, N-0315 Oslo, Norway. Univ Oslo, Ctr Math Applicat, N-0316 Oslo, Norway. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Pasadena, CA 91125 USA. Max Planck Inst Astrophys, D-85741 Garching, Germany. Univ Warsaw Observ, PL-00478 Warsaw, Poland. RP Eriksen, HK (reprint author), Univ Oslo, Inst Theoret Astrophys, N-0315 Oslo, Norway. RI Lilje, Per/A-2699-2012; OI Lilje, Per/0000-0003-4324-7794 NR 31 TC 168 Z9 167 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2007 VL 660 IS 2 BP L81 EP L84 DI 10.1086/518091 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169EB UT WOS:000246574400001 ER PT J AU Hollis, JM Jewell, PR Remijan, AJ Lovas, FJ AF Hollis, J. M. Jewell, P. R. Remijan, Anthony J. Lovas, F. J. TI Nonthermal continuum toward Sagittarius B2(N-LMH) SO ASTROPHYSICAL JOURNAL LA English DT Article DE HII regions; ISM : individual (Sagittarius B2(N-LMH)); radiation mechanisms : nonthermal; radio continuum : ISM ID GAMMA-RAY EMISSION; GALACTIC-CENTER; INTERSTELLAR; MOLECULE; B2; CONFIRMATION; REGION; ORIGIN; LINES; CORES AB An analysis of continuum antenna temperatures observed in the GBT spectrometer bandpasses is presented for observations toward Sgr B2(N-LMH). Since 2004, we have identified four new prebiotic molecules toward this source by means of rotational transitions between low-energy levels; concurrently, we have observed significant continuum in GBT bandpasses centered at 85 different frequencies in the range 1 - 48 GHz. The continuum heavily influences the molecular spectral features since we have observed far more absorption lines than emission lines for each of these new molecular species. Hence, it is important to understand the nature, distribution, and intensity of the underlying continuum in the GBT bandpasses for the purposes of radiative transfer, i.e., the means by which reliable molecular abundances are estimated. We find that the GBT spectrometer bandpass continuum is consistent with optically thin, nonthermal ( synchrotron) emission with a flux density spectral index of - 0.7 and a Gaussian source size of similar to 143 '' at 1 GHz that decreases with increasing frequency as. Some support for this model is provided by high-frequency VLA observations of Sgr B2. C1 NASA, Goddard Space Flight Ctr, Computat & Informat Sci & Technol Off, Greenbelt, MD 20771 USA. Natl Radio Astron Observ, Charlottesville, VA 22903 USA. Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Hollis, JM (reprint author), NASA, Goddard Space Flight Ctr, Computat & Informat Sci & Technol Off, Greenbelt, MD 20771 USA. NR 25 TC 13 Z9 13 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2007 VL 660 IS 2 BP L125 EP L128 DI 10.1086/518124 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169EB UT WOS:000246574400012 ER PT J AU Lissauer, JJ AF Lissauer, Jack J. TI Planets formed in habitable zones of M dwarf stars probably are deficient in volatiles SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrobiology; planetary systems : formation; planets and satellites : formation ID TERRESTRIAL PLANETS; SOLAR NEBULA; WATER; SIMULATIONS; TIMESCALES; ACCRETION; DELIVERY; SYSTEMS; BODIES; EARTHS AB Dynamical considerations, presented herein via analytic scalings and numerical experiments, imply that Earth-mass planets accreting in regions that become habitable zones of M dwarf stars form within several million years. Temperatures in these regions during planetary accretion are higher than those encountered by the material that formed the Earth. Collision velocities during and after the prime accretionary epoch are larger than for Earth. These factors suggest that planets orbiting low-mass main-sequence stars are likely to either be too distant ( and thus too cold) for carbon/water based life on their surfaces or have abundances of the required volatiles that are substantially less than on Earth. C1 NASA, Ames Res Ctr, Space Sci & Astrobiol Div, Moffett Field, CA 94035 USA. RP Lissauer, JJ (reprint author), NASA, Ames Res Ctr, Space Sci & Astrobiol Div, 245-3, Moffett Field, CA 94035 USA. NR 31 TC 43 Z9 43 U1 2 U2 8 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2007 VL 660 IS 2 BP L149 EP L152 DI 10.1086/518121 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169EB UT WOS:000246574400018 ER PT J AU Knutson, HA Charbonneau, D Allen, LE Fortney, JJ Agol, E Cowan, NB Showman, AP Cooper, CS Megeath, ST AF Knutson, Heather A. Charbonneau, David Allen, Lori E. Fortney, Jonathan J. Agol, Eric Cowan, Nicolas B. Showman, Adam P. Cooper, Curtis S. Megeath, S. Thomas TI A map of the day-night contrast of the extrasolar planet HD 189733b SO NATURE LA English DT Article ID SPITZER-SPACE-TELESCOPE; HOT JUPITERS; LIGHT CURVES; THERMAL EMISSION; GIANT PLANETS; ATMOSPHERES; 209458B; HD-189733; DYNAMICS; SPECTRA AB 'Hot Jupiter' extrasolar planets are expected to be tidally locked because they are close (< 0.05 astronomical units, where 1 AU is the average Sun - Earth distance) to their parent stars, resulting in permanent daysides and nightsides. By observing systems where the planet and star periodically eclipse each other, several groups have been able to estimate the temperatures of the daysides of these planets(1-3). A key question is whether the atmosphere is able to transport the energy incident upon the dayside to the nightside, which will determine the temperature at different points on the planet's surface. Here we report observations of HD 189733, the closest of these eclipsing planetary systems(4-6), over half an orbital period, from which we can construct a 'map' of the distribution of temperatures. We detected the increase in brightness as the dayside of the planet rotated into view. We estimate a minimum brightness temperature of 973 +/- 33 K and a maximum brightness temperature of 1,212 +/- 11K at a wavelength of 8 mm, indicating that energy from the irradiated dayside is efficiently redistributed throughout the atmosphere, in contrast to a recent claim for another hot Jupiter 7. Our data indicate that the peak hemisphereintegrated brightness occurs 16 +/- 6 degrees before opposition, corresponding to a hotspot shifted east of the substellar point. The secondary eclipse ( when the planet moves behind the star) occurs 120 +/- 24 s later than predicted, which may indicate a slightly eccentric orbit. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Ames Res Ctr, Space Sci & Astrobiol Div, Moffett Field, CA 94035 USA. SETI Inst, Mountain View, CA 94043 USA. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. Univ Toledo, Dept Phys & Astron, Toledo, OH 43606 USA. RP Knutson, HA (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM hknutson@cfa.harvard.edu RI Agol, Eric/B-8775-2013; OI Agol, Eric/0000-0002-0802-9145; Fortney, Jonathan/0000-0002-9843-4354; Charbonneau, David/0000-0002-9003-484X NR 30 TC 406 Z9 411 U1 4 U2 7 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 10 PY 2007 VL 447 IS 7141 BP 183 EP 186 DI 10.1038/nature05782 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 165WT UT WOS:000246338700037 PM 17495920 ER PT J AU Morabito, DD AF Morabito, David D. TI Solar corona-induced fluctuations on spacecraft signal amplitude observed during solar superior conjunctions of the Cassini spacecraft SO RADIO SCIENCE LA English DT Article ID ELECTRON-DENSITY FLUCTUATIONS; RADIO MEASUREMENTS; WIND; SCINTILLATION; SPECTRUM; SUN; SCATTERING AB During the superior solar conjunctions of interplanetary spacecraft, the emitted radio signals undergo increased amplitude scintillation, phase scintillation, and spectral broadening due to the intervening charged particles of the solar corona. The magnitude of these parameters generally increases as the angle between the spacecraft and the center of the Sun ( Sun-Earth probe ( SEP) angle) decreases as observed by the tracking station on Earth. During periods of quiescent background, the scintillation and spectral broadening measurements of spacecraft in the ecliptic follow well-defined trends of established models as a function of SEP angle and link frequency. The amplitude data acquired from the Cassini solar superior conjunctions of May 2000 and June 2001 during the maximum of Solar Cycle 23 were analyzed. The X band ( 8.4 GHz) and Ka band ( 32 GHz) scintillation measurements from the signal amplitude, the autocorrelation function of the amplitude, and the histogram of the amplitude samples acquired during quiescent periods were found to be consistent with models based on previous studies with other wavelengths. Amplitude autocorrelation functions of the signal amplitude yield information on the limiting scale sizes of the charged-particle blobs which constitute the solar corona. Evidence for very fast fluctuations at X band ( similar to 3 ms) was observed at SEP angles near 0.6 degrees. The histograms of the open-loop receiver amplitude samples were found to be consistent with the Rice distribution. The transition from strong to weak scintillation at Ka band was clearly captured in a Cassini 2001 solar conjunction pass that occurred near an SEP angle of 0.6 degrees ( 2.3 R(S)) as was expected for this frequency. The existing scintillation models were validated for Ka band, which is planned as a link frequency for deep space communications for upcoming missions. These results from this study are useful in providing information on solar activity on spacecraft signals at both X band and Ka band, which can be used to develop telecommunication strategies during solar superior conjunctions of planetary spacecraft. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Morabito, DD (reprint author), CALTECH, Jet Prop Lab, Bldg 238,Room 420,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM david.d.morabito@jpl.nasa.gov NR 30 TC 4 Z9 4 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD MAY 9 PY 2007 VL 42 IS 3 AR RS3002 DI 10.1029/2005RS003425 PG 16 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 168CK UT WOS:000246499800001 ER PT J AU Alsdorf, DE Rodriguez, E Lettenmaier, DP AF Alsdorf, Douglas E. Rodriguez, Ernesto Lettenmaier, Dennis P. TI Measuring surface water from space SO REVIEWS OF GEOPHYSICS LA English DT Review ID SYNTHETIC-APERTURE RADAR; TOPEX/POSEIDON SATELLITE ALTIMETRY; RASTER-BASED MODEL; RIVER DISCHARGE; AMAZON RIVER; LEVEL CHANGES; WETLAND DYNAMICS; INUNDATION AREA; GRAVITY-FIELD; ARCTIC-OCEAN AB Surface fresh water is essential for life, yet we have surprisingly poor knowledge of the spatial and temporal dynamics of surface freshwater discharge and changes in storage globally. For example, we are unable to answer such basic questions as "What is the spatial and temporal variability of water stored on and near the surface of all continents?'' Furthermore, key societal issues, such as the susceptibility of life to flood hazards, cannot be answered with the current global, in situ networks designed to observe river discharge at points but not flood events. The measurements required to answer these hydrologic questions are surface water area, the elevation of the water surface ( h), its slope (partial derivative h/partial derivative x), and temporal change (partial derivative h/partial derivative t). Advances in remote sensing hydrology, particularly over the past 10 years and even more recently, have demonstrated that these hydraulic variables can be measured reliably from orbiting platforms. Measurements of inundated area have been used to varying degrees of accuracy as proxies for discharge but are successful only when in situ data are available for calibration; they fail to indicate the dynamic topography of water surfaces. Radar altimeters have a rich, multidecadal history of successfully measuring elevations of the ocean surface and are now also accepted as capable tools for measuring h along orbital profiles crossing freshwater bodies. However, altimeters are profiling tools, which, because of their orbital spacings, miss too many freshwater bodies to be useful hydrologically. High spatial resolution images of partial derivative h/partial derivative t have been observed with interferometric synthetic aperture radar, but the method requires emergent vegetation to scatter radar pulses back to the receiving antenna. Essentially, existing spaceborne methods have been used to measure components of surface water hydraulics, but none of the technologies can singularly supply the water volume and hydraulic measurements that are needed to accurately model the water cycle and to guide water management practices. Instead, a combined imaging and elevation-measuring approach is ideal as demonstrated by the Shuttle Radar Topography Mission ( SRTM), which collected images of h at a high spatial resolution ( similar to 90 m) thus permitting the calculation of partial derivative h/partial derivative x. We suggest that a future satellite concept, the Water and Terrestrial Elevation Recovery mission, will improve upon the SRTM design to permit multitemporal mappings of h across the world's wetlands, floodplains, lakes, reservoirs, and rivers. C1 Ohio State Univ, Sch Earth Sci, Mendenhall Lab 383, Columbus, OH 43210 USA. Univ Washington, Dept Civil & Environm Engn, Seattle, WA 98195 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Alsdorf, DE (reprint author), Ohio State Univ, Sch Earth Sci, Mendenhall Lab 383, 125 S Oval Mall, Columbus, OH 43210 USA. EM alsdorf1@osu.edu RI lettenmaier, dennis/F-8780-2011 OI lettenmaier, dennis/0000-0003-3317-1327 NR 111 TC 275 Z9 278 U1 20 U2 140 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 8755-1209 EI 1944-9208 J9 REV GEOPHYS JI Rev. Geophys. PD MAY 9 PY 2007 VL 45 IS 2 AR RG2002 DI 10.1029/2006RG000197 PG 24 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 168CO UT WOS:000246500200001 ER PT J AU Real, E Law, KS Weinzierl, B Fiebig, M Petzold, A Wild, O Methven, J Arnold, S Stohl, A Huntrieser, H Roiger, A Schlager, H Stewart, D Avery, M Sachse, G Browell, E Ferrare, R Blake, D AF Real, E. Law, K. S. Weinzierl, B. Fiebig, M. Petzold, A. Wild, O. Methven, J. Arnold, S. Stohl, A. Huntrieser, H. Roiger, A. Schlager, H. Stewart, D. Avery, M. Sachse, G. Browell, E. Ferrare, R. Blake, D. TI Processes influencing ozone levels in Alaskan forest fire plumes during long-range transport over the North Atlantic SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BIOMASS-BURNING EMISSIONS; TROPICAL SOUTH-ATLANTIC; OPTICAL-PROPERTIES; ATMOSPHERIC CHEMISTRY; UNITED-STATES; MODEL; AEROSOL; SUMMER; IMPACT; O-3 AB [1] A case of long-range transport of a biomass burning plume from Alaska to Europe is analyzed using a Lagrangian approach. This plume was sampled several times in the free troposphere over North America, the North Atlantic and Europe by three different aircraft during the IGAC Lagrangian 2K4 experiment which was part of the ICARTT/ ITOP measurement intensive in summer 2004. Measurements in the plume showed enhanced values of CO, VOCs and NOy, mainly in form of PAN. Observed O-3 levels increased by 17 ppbv over 5 days. A photochemical trajectory model, CiTTyCAT, was used to examine processes responsible for the chemical evolution of the plume. The model was initialized with upwind data and compared with downwind measurements. The influence of high aerosol loading on photolysis rates in the plume was investigated using in situ aerosol measurements in the plume and lidar retrievals of optical depth as input into a photolysis code (Fast-J), run in the model. Significant impacts on photochemistry are found with a decrease of 18% in O-3 production and 24% in O-3 destruction over 5 days when including aerosols. The plume is found to be chemically active with large O-3 increases attributed primarily to PAN decomposition during descent of the plume toward Europe. The predicted O-3 changes are very dependent on temperature changes during transport and also on water vapor levels in the lower troposphere which can lead to O-3 destruction. Simulation of mixing/dilution was necessary to reproduce observed pollutant levels in the plume. Mixing was simulated using background concentrations from measurements in air masses in close proximity to the plume, and mixing timescales ( averaging 6.25 days) were derived from CO changes. Observed and simulated O-3/CO correlations in the plume were also compared in order to evaluate the photochemistry in the model. Observed slopes change from negative to positive over 5 days. This change, which can be attributed largely to photochemistry, is well reproduced by multiple model runs even if slope values are slightly underestimated suggesting a small underestimation in modeled photochemical O-3 production. The possible impact of this biomass burning plume on O-3 levels in the European boundary layer was also examined by running the model for a further 5 days and comparing with data collected at surface sites, such as Jungfraujoch, which showed small O-3 increases and elevated CO levels. The model predicts significant changes in O-3 over the entire 10 day period due to photochemistry but the signal is largely lost because of the effects of dilution. However, measurements in several other BB plumes over Europe show that O-3 impact of Alaskan fires can be potentially significant over Europe. C1 Univ Paris 06, Inst Pierre Simon Laplace, CNRS, Serv Aeron, F-75005 Paris, France. Deutsch Zentrum Luft & Raumfahrt, Inst Phys Atmosphare, D-82230 Wessling, Germany. Univ Cambridge, Dept Chem, Ctr Atmospher Sci, Cambridge CB2 1EW, England. Univ Reading, Dept Meteorol, Reading RG6 6BB, Berks, England. Univ Leeds, Sch Earth & Environm, Leeds LS2 9JT, W Yorkshire, England. Norwegian Inst Air Res, N-2027 Kjeller, Norway. Univ E Anglia, Sch Environm Sci, Norwich NR4 7TJ, Norfolk, England. NASA, Div Atmospher Sci, Langley Res Ctr, Hampton, VA 23681 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. RP Real, E (reprint author), Univ Paris 06, Inst Pierre Simon Laplace, CNRS, Serv Aeron, 3eme Etage,Tour 45-46,4 Pl Jussieu, F-75005 Paris, France. EM elsa.real@aero.jussieu.fr; kathy.law@aero.jussieu.fr; bernadett.weinzierl@dlr.de; markus.fiebig@dlr.de; oliver.wild@atm.ch.cam.ac.uk; j.methven@reading.ac.uk; sra@env.leeds.ac.uk; ast@nilu.no; heidi.huntrieser@dlr.de; anke-elisabeth.roiger@dlr.de; hans.schlager@dlr.de; d.stewart@uea.ac.uk; m.a.avery@larc.nasa.gov; g.w.sachse@larc.nasa.gov; e.v.browell@larc.nasa.gov; r.a.ferrare@larc.nasa.gov; dblake@orion.oac.uci.edu RI Stohl, Andreas/A-7535-2008; Wild, Oliver/A-4909-2009; Stewart, Dave/G-7491-2012; Fiebig, Markus/I-4872-2012; Petzold, Andreas/J-2347-2012; Arnold, Steve/B-8856-2014; Weinzierl, Bernadett/G-5319-2012 OI Stohl, Andreas/0000-0002-2524-5755; Wild, Oliver/0000-0002-6227-7035; Fiebig, Markus/0000-0002-3380-3470; Petzold, Andreas/0000-0002-2504-1680; Weinzierl, Bernadett/0000-0003-4555-5686 NR 60 TC 96 Z9 96 U1 2 U2 29 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 8 PY 2007 VL 112 IS D10 AR D10S41 DI 10.1029/2006JD007576 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 168AS UT WOS:000246495100001 ER PT J AU Reichle, RH Koster, RD Liu, P Mahanama, SPP Njoku, EG Owe, M AF Reichle, Rolf H. Koster, Randal D. Liu, Ping Mahanama, Sarith P. P. Njoku, Eni G. Owe, Manfred TI Comparison and assimilation of global soil moisture retrievals from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) and the Scanning Multichannel Microwave Radiometer (SMMR) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ENSEMBLE KALMAN FILTER; LAND DATA ASSIMILATION; CATCHMENT-BASED APPROACH; BRIGHTNESS TEMPERATURE; SURFACE PROCESSES; UNITED-STATES; MODEL; CLIMATE; METHODOLOGY; PARAMETERS AB [1] Two data sets of satellite surface soil moisture retrievals are first compared and then assimilated into the NASA Catchment land surface model. The first satellite data set is derived from 4 years of X-band (10.7 GHz) passive microwave brightness temperature observations by the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E), and the second is from 9 years of C-band (6.6 GHz) brightness temperature observations by the Scanning Multichannel Microwave Radiometer (SMMR). Despite the similarity in the satellite instruments, the retrieved soil moisture data exhibit very large differences in their multiyear means and temporal variability, primarily because they are computed with different retrieval algorithms. The satellite retrievals are also compared to a soil moisture product generated by the NASA Catchment land surface model when driven with surface meteorological data derived from observations. The climatologies of both satellite data sets are different from those of the model products. Prior to assimilation of the satellite retrievals into the land model, satellite-model biases are removed by scaling the satellite retrievals into the land model's climatology through matching of the respective cumulative distribution functions. Validation against in situ data shows that for both data sets the soil moisture fields from the assimilation are superior to either satellite data or model data alone. A global analysis of the innovations ( defined as the difference between the observations and the corresponding model values prior to the assimilation update) reveals how changes in model and observations error parameters may enhance filter performance in future experiments. C1 NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Sci Applicat Int Corp, Beltsville, MD USA. RP Reichle, RH (reprint author), NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Code 610-1, Greenbelt, MD 20771 USA. EM reichle@gmao.gsfc.nasa.gov RI Reichle, Rolf/E-1419-2012; Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 41 TC 154 Z9 157 U1 3 U2 26 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 8 PY 2007 VL 112 IS D9 AR D09108 DI 10.1029/2006JD008033 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 168AO UT WOS:000246494600007 ER PT J AU Russell, PB Livingston, JM Redemann, J Schmid, B Ramirez, SA Eilers, J Kahn, R Chu, DA Remer, L Quinn, PK Rood, MJ Wang, W AF Russell, P. B. Livingston, J. M. Redemann, J. Schmid, B. Ramirez, S. A. Eilers, J. Kahn, R. Chu, D. A. Remer, L. Quinn, P. K. Rood, M. J. Wang, W. TI Multi-grid-cell validation of satellite aerosol property retrievals in INTEX/ITCT/ICARTT 2004 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID COLUMNAR WATER-VAPOR; RESOLUTION IMAGING SPECTRORADIOMETER; AIRBORNE SUN PHOTOMETER; LOWER TROPOSPHERIC AEROSOL; GROUND-BASED MEASUREMENTS; OPTICAL-DEPTH SPECTRA; CLEAR-SKY REFLECTANCE; FINE-MODE FRACTION; ACE-ASIA; IN-SITU AB Aerosol transport off the US Northeast coast during the Summer 2004 International Consortium for Atmospheric Research on Transport and Transformation ( ICARTT) Intercontinental Chemical Transport Experiment ( INTEX) and Intercontinental Transport and Chemical Transformation ( ITCT) experiments produced a wide range of aerosol types and aerosol optical depth ( AOD) values, often with strong horizontal AOD gradients. In these conditions we flew the 14-channel NASA Ames Airborne Tracking Sun photometer ( AATS) on a Jetstream 31 ( J31) aircraft. Legs flown at low altitude ( usually <= 100 m ASL) provided comparisons of AATS AOD spectra to retrievals for 90 grid cells of the satellite radiometers MODIS-Terra, MODIS-Aqua, and MISR, all over the ocean. Characterization of the retrieval environment was aided by using vertical profiles by the J31 ( showing aerosol vertical structure) and, on occasion, shipboard measurements of light scattering and absorption. AATS provides AOD at 13 wavelengths 1 from 354 to 2138 nm, spanning the range of aerosol retrieval wavelengths for MODIS over ocean ( 466-2119 nm) and MISR ( 446-866 nm). Midvisible AOD on low-altitude J31 legs in satellite grid cells ranged from 0.05 to 0.9, with horizontal gradients often in the range 0.05 to 0.13 per 10 km. When possible, we used ship measurements of humidified aerosol scattering and absorption to estimate AOD below the J31. In these cases, which had J31 altitudes 60-110 m ASL ( typical of J31 low-altitude transects), estimated midvisible AOD below the J31 ranged from 0.003 to 0.013, with mean 0.009 and standard deviation 0.003. These values averaged 6% of AOD above the J31. MISR-AATS comparisons on 29 July 2004 in 8 grid cells ( each similar to 17.6 km x 17.6 km) show that MISR versions 15 and 16 captured the AATS-measured AOD gradient ( correlation coefficient R-2 = 0.87 to 0.92), but the MISR gradient was somewhat weaker than the AATS gradient. The large AOD ( midvisible values up to similar to 0.9) and differing gradients in this case produced root-mean-square ( RMS) MISR-AATS AOD differences of 0.03 to 0.21 ( 9 to 31%). MISR V15 angstrom ngstrom exponent alpha ( = -dlnAOD/dln lambda) was closer to AATS than was MISR V16. MODIS-AATS AOD comparisons on 8 overpasses using 61 grid cells ( each nominally 10 km x 10 km) had R-2 x 0.97, with RMS AOD difference similar to 0.03 (similar to 20%). About 87% of the MODIS AOD retrievals differed from AATS values by less than the predicted MODIS over-ocean uncertainty, Delta(tau) = +/- 0.03 +/- 0.05 tau. In contrast to the small MODIS-AATS differences in AOD, MODIS-AATS differences in A ngstrom exponent a were large: RMS differences for alpha( 553, 855 nm) were 0.28 for MODIS-Terra and 0.64 for MODIS-Aqua; RMS differences for alpha( 855, 2119 nm) were larger still, 0.61 for MODIS-Terra and 1.14 for MODIS-Aqua. The largest MODIS-AATS A ngstrom exponent differences were associated with small AOD values, for which MODIS AOD relative uncertainty is large. Excluding cases with AOD( 855 nm) < 0.1 reduced MODIS-AATS a differences substantially. In one grid cell on 21 July 2004, smoke over cloud appeared to impair the MODIS-Aqua cloud mask, resulting in retrieved AODs that significantly exceeded AATS values. Experiments with extending MODIS retrievals into the glint mask yielded MODIS AODs consistently less than AATS AODs, especially at long wavelength, indicating that the current MODIS glint mask limits should not be reduced to the extent tried here. The sign of the AOD differences within the glint mask ( MODI AOD < AATS AOD) is consistent with ship-measured wind speeds there. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SRI Int, Menlo Pk, CA 94025 USA. Bay Area Environm Res Inst, Sonoma, CA 95476 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Illinois, Dept Civil & Environm Engn, Urbana, IL 61801 USA. RP Russell, PB (reprint author), NASA, Ames Res Ctr, MS 245-5, Moffett Field, CA 94035 USA. EM philip.b.russell@nasa.gov; jlivingston@mail.arc.nasa.gov; jredemann@mail.arc.nasa.gov; bschmid@mail.arc.nasa.gov; s.a.ramirez@mail.arc.nasa.gov; james.a.eilers@nasa.gov; ralph.kahn@jpl.nasa.gov; achu@climate.gsfc.nasa.gov; patricia.k.quinn@noaa.gov; mrood@uiuc.edu; weiwang@uiuc.edu RI Kahn, Ralph/D-5371-2012; Quinn, Patricia/R-1493-2016 OI Kahn, Ralph/0000-0002-5234-6359; Quinn, Patricia/0000-0003-0337-4895 NR 65 TC 26 Z9 26 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 8 PY 2007 VL 112 IS D12 AR D12S09 DI 10.1029/2006JD007606 PG 29 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 168AW UT WOS:000246495500001 ER PT J AU Rouille, G Arold, M Staicu, A Krasnokutski, S Huisken, F Henning, T Tan, X Salama, F AF Rouille, G. Arold, M. Staicu, A. Krasnokutski, S. Huisken, F. Henning, Th. Tan, X. Salama, F. TI S-1((1)A(1))<- S-0((1)A(1)) transition of benzo[g, h, i]perylene in supersonic jets and rare gas matrices SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID RING-DOWN SPECTROSCOPY; POLYCYCLIC AROMATIC-HYDROCARBONS; DIFFERENTIAL-OVERLAP TECHNIQUE; ABSORPTION-SPECTROSCOPY; FLUORESCENCE-SPECTRA; EMISSION-SPECTROSCOPY; SEMIEMPIRICAL METHODS; INTERMEDIATE NEGLECT; HELIUM DROPLETS; PERYLENE AB The study of the S-1((1)A(1))<- S-0((1)A(1)) transition of benzo[g,h,i]perylene (BghiP, C22H12) in supersonic jets and solid rare gas matrices is reported. In the jet-cooled spectrum, the origin band position is located at 25 027.1 +/- 0.2 cm(-1), the assignment being supported by the analysis of vibrational shifts and rotational band contours. Except for the origin band, which is weak, all bands are attributed to the fundamental excitation of nontotally symmetric b(1) vibrational modes of S-1. The intensity pattern is interpreted as a consequence of the weak oscillator strength of the electronic transition combined with intensity-borrowing through vibronic interaction between the S-1((1)A(1)) and S-2(B-1(1)) states. The spectra of the S-1((1)A(1))<- S-0((1)A(1)) and S-2(B-1(1))<- S-0((1)A(1)) transitions have also been measured for BghiP in solid neon and argon matrices. The comparison of the redshifts determined for either transition reveals that the polarizability of BghiP is larger in its S-2 than in its S-1 state. Bandwidths of 2.7 cm(-1) measured in supersonic jets, which provide conditions relevant for astrophysics, are similar to those of most diffuse interstellar bands. The electronic transitions of BghiP are found to lie outside the ranges covered by present databases. From the comparison between experimental spectra and theoretical computations, it is concluded that the accuracy of empirical and ab initio approaches in predicting electronic energies is still not sufficient to identify astrophysically interesting candidates for spectroscopic laboratory studies. (C) 2007 American Institute of Physics. C1 Univ Jena, Inst Festkorperphys, D-07743 Jena, Germany. Max Planck Inst Astron, D-69117 Heidelberg, Germany. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Rouille, G (reprint author), Univ Jena, Inst Festkorperphys, Helmholtzweg 3, D-07743 Jena, Germany. EM friedrich.huisken@uni-jena.de RI Staicu, Angela/B-6741-2011; Salama, Farid/A-8787-2009; Rouille, Gael/K-7075-2016 OI Salama, Farid/0000-0002-6064-4401; Rouille, Gael/0000-0002-4016-1461 NR 44 TC 17 Z9 17 U1 2 U2 10 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 7 PY 2007 VL 126 IS 17 AR 174311 DI 10.1063/1.2727467 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 165DT UT WOS:000246284800019 PM 17492867 ER PT J AU Xing, X Reed, B Lau, KC Ng, CY Zhang, X Ellison, GB AF Xing, Xi Reed, Beth Lau, Kai-Chung Ng, C. Y. Zhang, Xu Ellison, G. Barney TI Vacuum ultraviolet laser pulsed field ionization-photoelectron study of allyl radical CH2CHCH2 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID BENZYL RADICALS; RYDBERG STATES; SPECTROSCOPY; PHOTOIONIZATION; SPECTRUM; ENERGY; PREDICTIONS; THRESHOLD; MOLECULES; BANDS AB The pulsed field ionization-photoelectron (PFI-PE) spectrum of allyl radical CH2CHCH2 (C3H5) in the energy range of 65 200-66 600 cm(-1) has been measured using vacuum ultraviolet laser. Based on the simulation of the rotational structures resolved in the vibrational PFI-PE bands of C3H5+(X (1)A(1);0(0+) and nu(+)(7)=1), the ionization energies (IEs) of C3H5(X (2)A(2);0(0)) to form C3H5+(X (1)A(1);O0+ and nu(+)(7)=1) are determined to be 65 584.6 +/- 2.0 cm(-1) (8.131 46 +/- 0.000 25 eV) and 66 020.9 +/- 2.0 cm(-1) (8.185 56 +/- 0.000 25 eV), respectively, where nu(+)(7)(a(1)) is the symmetric C-C-C bending mode of C3H5+(X (1)A(1)). These values are compared to IE(C3H5) values obtained in previous experimental and high-level ab initio quantum theoretical studies. (C) 2007 American Institute of Physics. C1 Univ Calif Davis, Dept Chem, Davis, CA 95616 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Xing, X (reprint author), Univ Calif Davis, Dept Chem, Davis, CA 95616 USA. EM cyng@chem.ucdavis.edu; xu.zhang@jpl.nasa.gov; Barney@jila.colorado.edu OI LAU, Kai Chung /0000-0003-2125-6841 NR 32 TC 15 Z9 15 U1 2 U2 5 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 7 PY 2007 VL 126 IS 17 AR 171101 DI 10.1063/1.2737443 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 165DT UT WOS:000246284800001 PM 17492849 ER PT J AU Zhang, X Nimlos, MR Ellison, GB Varner, ME Stanton, JF AF Zhang, Xu Nimlos, Mark R. Ellison, G. Barney Varner, Mychel E. Stanton, John F. TI Vibrational overtone spectrum of matrix isolated cis, cis-HOONO SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID NITRIC-ACID; PEROXYNITROUS ACID; GAS-PHASE; INFRARED-ABSORPTION; ACTION SPECTROSCOPY; SOLID ARGON; PERTURBATION; KINETICS; TEMPERATURE; PHOTOLYSIS AB Cis, cis-peroxynitrous acid is known to be an intermediate in atmospheric reactions between OH and NO2 as well as HOO and NO. The infrared absorption spectra of matrix-isolated cc-HOONO and cc-DOONO in argon have been observed in the range of 500-8000 cm(-1). Besides the seven fundamental vibrational modes that have been assigned earlier for this molecule [Zhang , J. Chem. Phys. 124, 084305 (2006)], more than 50 of the overtone and combination bands have been observed for cc-HOONO and cc-DOONO. Ab initio CCSD(T)/atomic natural orbital anharmonic force field calculations were used to help guide the assignments. Based on this study of the vibrational overtone transitions of cis, cis-HOONO that go as high as 8000 cm(-1) and the earlier paper on the vibrational fundamentals, we conclude that the CCSD(T)/ANO anharmonic frequencies seem to correct to +/- 35 cm(-1). The success of the theoretically predicted anharmonic frequencies {upsilon} in assigning overtone spectra of HOONO up to 8000 cm(-1) suggests that the CCSD(T)/ANO method is producing a reliable potential energy surface for this reactive molecule. (C) 2007 American Institute of Physics. C1 Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NREL, Ctr Renewable Chem Technol & Mat, Golden, CO 80401 USA. Univ Texas, Dept Chem, Inst Theoret Chem, Austin, TX 78712 USA. RP Zhang, X (reprint author), Univ Colorado, Dept Chem & Biochem, Campus Box 215, Boulder, CO 80309 USA. EM xu.zhang@jpl.nasa.gov; mark_nimlos@nrel.gov; barney@jila.colorado.edu; mvarner@mail.utexas.edu; jfstanton@mail.utexas.edu NR 35 TC 7 Z9 7 U1 3 U2 10 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 7 PY 2007 VL 126 IS 17 AR 174308 DI 10.1063/1.2720392 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 165DT UT WOS:000246284800016 PM 17492864 ER PT J AU Gulden, LE Rosero, E Yang, ZL Rodell, M Jackson, CS Niu, GY Yeh, PJF Famiglietti, J AF Gulden, Lindsey E. Rosero, Enrique Yang, Zong-Liang Rodell, Matthew Jackson, Charles S. Niu, Guo-Yue Yeh, Pat J. -F. Famiglietti, James TI Improving land-surface model hydrology: Is an explicit aquifer model better than a deeper soil profile? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CLIMATE EXPERIMENT GRACE; GRAVITY RECOVERY; ILLINOIS; PARAMETERIZATION; SCHEME; TIME AB We use Monte Carlo analysis to show that explicit representation of an aquifer within a land-surface model (LSM) decreases the dependence of model performance on accurate selection of subsurface hydrologic parameters. Within the National Center for Atmospheric Research Community Land Model (CLM) we evaluate three parameterizations of vertical water flow: (1) a shallow soil profile that is characteristic of standard LSMs; (2) an extended soil profile that allows for greater variation in terrestrial water storage; and (3) a lumped, unconfined aquifer model coupled to the shallow soil profile. North American Land Data Assimilation System meteorological forcing data (1997-2005) drive the models as a single column representing Illinois, USA. The three versions of CLM are each run 22,500 times using a random sample of the parameter space for soil texture and key hydrologic parameters. Other parameters remain constant. Observation-based monthly changes in state-averaged terrestrial water storage (dTWS) are used to evaluate the model simulations. After single-criteria parameter exploration, the schemes are equivalently adept at simulating dTWS. However, explicit representation of groundwater considerably decreases the sensitivity of modeled dTWS to errant parameter choices. We show that approximate knowledge of parameter values is not sufficient to guarantee realistic model performance: because interaction among parameters is significant, they must be prescribed as a congruent set. C1 Univ Texas, John A & Katherine G Jackson Sch Geosci, Dept Geol Sci, Austin, TX 78712 USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. Univ Texas, John A & Katherine G Jackson Sch Geosci, Inst Geophys, Austin, TX 78758 USA. Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92696 USA. RP Gulden, LE (reprint author), Univ Texas, John A & Katherine G Jackson Sch Geosci, Dept Geol Sci, 1 Univ Stn C1100, Austin, TX 78712 USA. EM liang@mail.utexas.edu RI Jackson, Charles/A-2202-2009; YEH, Pat/B-2758-2011; Rodell, Matthew/E-4946-2012; Yang, Zong-Liang/B-4916-2011; Niu, Guo-Yue/B-8317-2011 OI Jackson, Charles/0000-0002-2870-4494; YEH, Pat/0000-0001-7629-3362; Rodell, Matthew/0000-0003-0106-7437; NR 22 TC 44 Z9 44 U1 2 U2 16 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 5 PY 2007 VL 34 IS 9 AR L09402 DI 10.1029/2007GL029804 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 165LE UT WOS:000246306200010 ER PT J AU Gutsev, GL Mochena, MD Bauschlicher, CW AF Gutsev, G. L. Mochena, M. D. Bauschlicher, C. W., Jr. TI Structure and magnetic properties of (GaAs)(n)Mn-m and (GaAs)(n)Fe-m clusters SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SMALL GAAS CLUSTERS; ELECTRONIC-STRUCTURE; IONIZATION ENERGIES; SPINTRONICS; (GA,MN)AS; DIMERS; IONS AB The electronic and geometrical structures of (GaAS)(n)Mn-m and (GaAS)(n)Fe-m clusters (for m = 1, n = 2-4, for m = 2, n = 1-4, and for m = 3. n = 4) are studied using density functional theory with generalized gradient approximation. The clusters are found to possess a large number of isomers that are close in total energy. For the clusters with multiple metal atoms, the ferromagnetic and antiferromagnetic couplings of the excess spin densities at the metal sites are close in energy. (GaAs)(2)Mn-2, (GaAs)(3)Mn-2, and (GaAs)(4)Mn-3 have antiferromagnetic ground states, while all of the Fe-n-containing species, GaAsMn2 and (GaAs)(4)Mn-2 have ferromagnetic ground states. (c) 2007 Elsevier B.V. All rights reserved. C1 Florida A&M Univ, Dept Phys, Tallahassee, FL 32307 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Gutsev, GL (reprint author), Florida A&M Univ, Dept Phys, Tallahassee, FL 32307 USA. EM gennady.gutsev@famu.edu NR 35 TC 9 Z9 9 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 4 PY 2007 VL 439 IS 1-3 BP 95 EP 101 DI 10.1016/j.cplett.2007.03.050 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 169RQ UT WOS:000246609800020 ER PT J AU Liu, CT Zipser, E Garrett, T Jiang, JH Su, H AF Liu, Chuntao Zipser, Ed Garrett, Tim Jiang, Jonathan H. Su, Hui TI How do the water vapor and carbon monoxide "tape recorders" start near the tropical tropopause? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GAS EXPERIMENT-II; DEEP CONVECTION; STRATOSPHERIC AEROSOL; GLOBAL DISTRIBUTION; CIRRUS; DEHYDRATION; TRANSPORT; TEMPERATURES; HUMIDITY; RADAR AB This paper evaluates geo-seasonal relationships in tropical deep convection using radar and infrared data from Tropical Rainfall Measuring Mission (TRMM), near tropopause thin clouds from Stratospheric Air and Gas Experiment (SAGE) II, water vapor and carbon monoxide (CO) from the Earth Observing System (EOS) Microwave Limb Sounder (MLS), and the tropopause temperature from National Center of Environment Prediction (NCEP) reanalysis data. Geo-seasonal variations in MLS water vapor at 146 hPa and 100 hPa are negatively correlated, which points to dehydration at the tropical tropopause. Water vapor at 146 hPa is highly correlated with tropical deep convection and thin clouds, but at 100 hPa it is more highly correlated with the tropopause temperature. There is a high correlation between the geo-seasonal variations of 14-16 km thin cloud and cold clouds from deep convection. However, at 16-18 km, thin clouds are highly correlated with the tropopause temperature as well as with deep convection. There is a semi-annual cycle in CO concentrations at 100 hPa and 146 hPa. The variability is consistent with the convolved seasonal variation of deep convection and surface biomass burning. The annual cycle of water vapor at 100 hPa correlates with the seasonal variability of "freezing and drying" between 146 hPa and 100 hPa, which in turn correlates with changes in tropopause temperature associated with deep convective lifting or large scale ascent. C1 Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liu, CT (reprint author), Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. EM liuct@met.utah.edu NR 32 TC 30 Z9 30 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 4 PY 2007 VL 34 IS 9 AR L09804 DI 10.1029/2006GL029234 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 165LD UT WOS:000246306100003 ER PT J AU Rahmstorf, S Cazenave, A Church, JA Hansen, JE Keeling, RF Parker, DE Somerville, RCJ AF Rahmstorf, Stefan Cazenave, Anny Church, John A. Hansen, James E. Keeling, Ralph F. Parker, David E. Somerville, Richard C. J. TI Recent climate observations compared to projections SO SCIENCE LA English DT Article DE ocean; sea level C1 Potsdam Inst Climate Impact Res, D-14482 Potsdam, Germany. Lab Etud Geophys & Oceanog, F-31400 Toulouse, France. CSIRO, Marine & Atmospher Res & Antarctic Climate & Ecos, Hobart, Tas 7001, Australia. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Hadley Ctr, Met Off, Exeter EX1 3PB, Devon, England. RP Rahmstorf, S (reprint author), Potsdam Inst Climate Impact Res, D-14482 Potsdam, Germany. RI Rahmstorf, Stefan/A-8465-2010; Church, John/A-1541-2012; kohki, sowa/D-2955-2011 OI Rahmstorf, Stefan/0000-0001-6786-7723; Church, John/0000-0002-7037-8194; NR 6 TC 352 Z9 364 U1 4 U2 83 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 4 PY 2007 VL 316 IS 5825 BP 709 EP 709 DI 10.1126/science.1136843 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 163RR UT WOS:000246181400035 PM 17272686 ER PT J AU Margot, JL Peale, SJ Jurgens, RF Slade, MA Holin, IV AF Margot, J. L. Peale, S. J. Jurgens, R. F. Slade, M. A. Holin, I. V. TI Large longitude libration of Mercury reveals a molten core SO SCIENCE LA English DT Article ID MAGNETIC-FIELD; CRUSTAL REMANENCE; THERMAL EVOLUTION; POLAR ANOMALIES; PLANET MERCURY; SOLAR SYSTEM; RADAR; ROTATION; SHELL; SPIN AB Observations of radar speckle patterns tied to the rotation of Mercury establish that the planet occupies a Cassini state with obliquity of 2.11 +/- 0.1 arc minutes. The measurements show that the planet exhibits librations in longitude that are forced at the 88-day orbital period, as predicted by theory. The large amplitude of the oscillations, 35.8 +/- 2 arc seconds, together with the Mariner 10 determination of the gravitational harmonic coefficient C-22, indicates that the mantle of Mercury is decoupled from a core that is at least partially molten. C1 Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Space Res Inst, Moscow, Russia. RP Margot, JL (reprint author), Cornell Univ, Dept Astron, 304 Space Sci Bldg, Ithaca, NY 14853 USA. EM jlm@astro.cornell.edu RI Margot, Jean-Luc/A-6154-2012 OI Margot, Jean-Luc/0000-0001-9798-1797 NR 45 TC 173 Z9 175 U1 3 U2 12 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 4 PY 2007 VL 316 IS 5825 BP 710 EP 714 DI 10.1126/science.1140514 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 163RR UT WOS:000246181400036 PM 17478713 ER PT J AU Squyres, SW Aharonson, O Clark, BC Cohen, BA Crumpler, L de Souza, PA Farrand, WH Gellert, R Grant, J Grotzinger, JP Haldemann, AFC Johnson, JR Klingelhofer, G Lewis, KW Li, R McCoy, T McEwen, AS McSween, HY Ming, DW Moore, JM Morris, RV Parker, TJ Rice, JW Ruff, S Schmidt, M Schroder, C Soderblom, LA Yen, A AF Squyres, S. W. Aharonson, O. Clark, B. C. Cohen, B. A. Crumpler, L. de Souza, P. A. Farrand, W. H. Gellert, R. Grant, J. Grotzinger, J. P. Haldemann, A. F. C. Johnson, J. R. Klingelhoefer, G. Lewis, K. W. Li, R. McCoy, T. McEwen, A. S. McSween, H. Y. Ming, D. W. Moore, J. M. Morris, R. V. Parker, T. J. Rice, J. W., Jr. Ruff, S. Schmidt, M. Schroeder, C. Soderblom, L. A. Yen, A. TI Pyroclastic activity at home plate in Gusev Crater, Mars SO SCIENCE LA English DT Article ID SPIRIT AB Home Plate is a layered plateau in Gusev crater on Mars. It is composed of clastic rocks of moderately altered alkali basalt composition, enriched in some highly volatile elements. A coarse-grained lower unit lies under a finer-grained upper unit. Textural observations indicate that the lower strata were emplaced in an explosive event, and geochemical considerations favor an explosive volcanic origin over an impact origin. The lower unit likely represents accumulation of pyroclastic materials, whereas the upper unit may represent eolian reworking of the same pyroclastic materials. C1 Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Lockheed Martin Corp, Littleton, CO 80127 USA. Univ New Mexico, Inst Meteorit, Albuquerque, NM 87131 USA. New Mexico Museum Nat Hist & Sci, Albuquerque, NM 87104 USA. Vallourec Res Ctr, F-59260 Aulnoye Aymeries, France. Space Sci Inst, Boulder, CO 80301 USA. Univ Guelph, Dept Phys, Guelph, ON N1G 2W1, Canada. Smithsonian Inst, Ctr Earth & Planetary Studies, Washington, DC 20560 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Johannes Gutenberg Univ Mainz, Inst Anorgan & Analyt Chem, D-6500 Mainz, Germany. Ohio State Univ, Dept Civil & Environm Engn & Geodet Sci, Columbus, OH 43210 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Mineral Sci, Washington, DC 20560 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Tennessee, Dept Earth & Planetary Sci, Knoxville, TN 37996 USA. NASA, Lyndon B Johnson Space Ctr, Astromat Res & Explorat Sci, Houston, TX 77058 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. RP Squyres, SW (reprint author), Cornell Univ, Dept Astron, Space Sci Bldg, Ithaca, NY 14853 USA. RI de Souza, Paulo/B-8961-2008; Schroder, Christian/B-3870-2009; Lewis, Kevin/E-5557-2012; Johnson, Jeffrey/F-3972-2015 OI de Souza, Paulo/0000-0002-0091-8925; Schroder, Christian/0000-0002-7935-6039; NR 17 TC 101 Z9 102 U1 0 U2 21 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD MAY 4 PY 2007 VL 316 IS 5825 BP 738 EP 742 DI 10.1126/science.1139045 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 163RR UT WOS:000246181400044 PM 17478719 ER PT J AU Wu, LG AF Wu, Liguang TI Impact of Saharan air layer on hurricane peak intensity SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STRONG ASSOCIATION; TROPICAL CYCLONES; RAINFALL; CLIMATE; SAHEL; DISTURBANCES; INCREASE; DROUGHT; STORMS AB The Saharan air layer (SAL), which is associated with African dust outbreaks, forms as air moves across the Sahara Desert, containing substantial amounts of mineral dust. While the relationships of Sahel rainfall with African dust outbreaks and Atlantic hurricane activity have been documented in previous studies, analyses of various independent datasets show that the Sahel rainfall, SAL activity and hurricane peak intensity in the Atlantic basin are highly correlated. The long-term trend in hurricane peak intensity generally follows the Sahel rainfall and SAL activity. The decreasing trend in hurricane intensity by the mid-1980s was associated with the enhancing SAL activity (drying relative humidity and enhancing vertical shear) and the severe drought in the Sahel, while the recent moderate increasing trend in hurricane intensity is consistent with the weakening SAL activity (wetting relative humidity, weakening vertical shear and decreasing dust load) and the ameliorating Sahel drought. This study suggests that the SAL may act as a link between the summer African monsoon and Atlantic hurricane activity. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20071 USA. Univ Maryland Baltimore Cty, Goddard Earth & Technol Ctr, Catonsville, MD USA. RP Wu, LG (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 613-1, Greenbelt, MD 20071 USA. EM liguang@agnes.gsfc.nasa.gov NR 24 TC 42 Z9 43 U1 0 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 3 PY 2007 VL 34 IS 9 AR L09802 DI 10.1029/2007GL029564 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 165LC UT WOS:000246306000003 ER PT J AU Dong, JR Ni-Meister, W Houser, PR AF Dong, Jiarui Ni-Meister, Wenge Houser, Paul R. TI Impacts of vegetation and cold season processes on soil moisture and climate relationships over Eurasia SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MODEL SIMULATIONS; LAND; VARIABILITY; ATMOSPHERE; PRECIPITATION; TEMPERATURE; WETNESS; SCALES; MEMORY; DEFORESTATION AB A number of modeling studies have addressed soil moisture persistence and its effects on the atmosphere. Such analyses are particularly valuable for seasonal to interannual prediction. In this study, we perform an observation-based study to further investigate the impacts of vegetation and cold season processes on soil moisture persistence and climate feedbacks. The joint analysis of independent meteorological, soil moisture and land cover measurements, without the use of a model, in the former Soviet Union provides a unique look at soil moisture-climate relationships at seasonal to interannual timescales. Averaged data over the growing season show a strong consistency between soil moisture and precipitation over grassland dominant regions, suggesting that precipitation anomalies are a dominant control of soil moisture at interannual timescales. Investigation of soil moisture persistence at the seasonal timescale shows a strong correlation between soil moisture in spring and the subsequent precipitation in summer over forest dominant regions and between cold season precipitation accumulation in winter and soil moisture in the following spring. Our findings can be explained by the theory proposed by Koster and Suarez (2001) and are consistent with the results from other modeling studies. Although it is hard to obtain the statistical meaningful conclusions because of the short data records, our results show the potential role of vegetation and cold season processes in land-atmosphere interactions. Further modeling studies and analyses using long in situ data records are necessary to fully verify our results. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. CUNY Hunter Coll, Dept Geog, New York, NY 10021 USA. Ctr Res Environm & Water, Calverton, MD 20705 USA. George Mason Univ, Fairfax, VA 22030 USA. RP Dong, JR (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Code 614-3, Greenbelt, MD 20771 USA. EM jiarui@hsb.gsfc.nasa.gov RI Houser, Paul/J-9515-2013 OI Houser, Paul/0000-0002-2991-0441 NR 37 TC 6 Z9 6 U1 2 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 3 PY 2007 VL 112 IS D9 AR D09106 DI 10.1029/2006JD007774 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 165LI UT WOS:000246306600006 ER PT J AU Luo, M Rinsland, CP Rodgers, CD Logan, JA Worden, H Kulawik, S Eldering, A Goldman, A Shephard, MW Gunson, M Lampel, M AF Luo, M. Rinsland, C. P. Rodgers, C. D. Logan, J. A. Worden, H. Kulawik, S. Eldering, A. Goldman, A. Shephard, M. W. Gunson, M. Lampel, M. TI Comparison of carbon monoxide measurements by TES and MOPITT: Influence of a priori data and instrument characteristics on nadir atmospheric species retrievals SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPOSPHERIC EMISSION SPECTROMETER; POLLUTION; PROFILES AB Comparisons of tropospheric carbon monoxide (CO) volume mixing ratio profiles and total columns are presented from nadir-viewing measurements made by the Tropospheric Emission Spectrometer (TES) on the NASA Aura satellite and by the Measurements of Pollution in the Troposphere (MOPITT) instrument on the NASA Terra satellite. In this paper, we first explore the factors that relate the retrieved and the true species profiles. We demonstrate that at a given location and time the retrieved species profiles reported by different satellite instrument teams can be very different from each other. We demonstrate the influence of the a priori data and instrument characteristics on the CO products from TES and MOPITT and on their comparisons. Direct comparison of TES and MOPITT retrieved CO profiles and columns show significant differences in the lower and upper troposphere. To perform a more proper and rigorous comparison between the two instrument observations we allow for different a priori profiles and averaging kernels. We compare (1) TES retrieved CO profiles adjusted to the MOPITT a priori with the MOPITT retrievals and (2) the above adjusted TES CO profiles with the MOPITT profiles vertically smoothed by the TES averaging kernels. These two steps greatly improve the agreement between the CO profiles and the columns from the two instruments. No systematic differences are found as a function of latitude in the final comparisons. These results show that knowledge of the a priori profiles, the averaging kernels, and the error covariance matrices in the standard data products provided by the instrument teams and understanding their roles in the retrieval products are essential in quantitatively interpreting both retrieved profiles and the derived total or partial columns for scientific applications. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Oxford, Clarendon Lab, Oxford OX1 3PU, England. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Univ Denver, Dept Phys, Denver, CO 80208 USA. Atmospher & Environm Res Inc, Lexington, MA 02421 USA. Raytheon Informat Solut, Pasadena, CA 91101 USA. RP Luo, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM mluo@jpl.nasa.gov NR 21 TC 64 Z9 65 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 3 PY 2007 VL 112 IS D9 AR D09303 DI 10.1029/2006JD007663 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 165LI UT WOS:000246306600004 ER PT J AU Prokopuk, N Son, KA Waltz, C AF Prokopuk, Nicholas Son, Kyung-Ah Waltz, Chad TI Electron tunneling through fluid solvents SO JOURNAL OF PHYSICAL CHEMISTRY C LA English DT Article ID ORGANIC-MOLECULES; TRANSFER KINETICS; TRANSFER PROTEINS; DISTANCE; PATHWAYS; DEVICES; WATER; REORGANIZATION; CONDUCTANCE; DEPENDENCE AB Despite the biological, chemical, and physical importance of electron tunneling across noncovalent matrices, relatively little is known about the ability of the various nonbonding interactions (hydrogen-bonding and van der Waals forces) to mediate charge transfer. Herein, we report the steady-state current-voltage (I-V) profiles of nanometer junctions filled with water and a variety of organic solvents. The maximum currents for the solvents studied span 6 orders of magnitude. The I-V data can be reasonably fit to a simple electron tunneling model with a rectangular energy barrier representing the solvent. Protic solvents provide the smallest barrier heights (greatest tunneling currents), and nonpolar solvents exhibit the largest energy barriers (lowest currents). Trends in the barrier heights with the strength of the solvent-solvent interactions (hydrogen-bonding < dipole-dipole < dispersion interactions) indicate that the solvent's cohesive energy largely determines/limits the barrier heights of the fluid systems rather than the electronic structure of the solvent molecule (e.g., electron affinity or ionization potential). These results demonstrate that facile electron tunneling through nonbonding media must be accompanied by relatively strong intermolecular interactions. C1 USN, Air Warfare Ctr, Chem & Mat Div, China Lake, CA 93555 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Prokopuk, N (reprint author), USN, Air Warfare Ctr, Chem & Mat Div, China Lake, CA 93555 USA. EM nicholas.prokopuk@navy.mil NR 56 TC 10 Z9 10 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1932-7447 J9 J PHYS CHEM C JI J. Phys. Chem. C PD MAY 3 PY 2007 VL 111 IS 17 BP 6533 EP 6537 DI 10.1021/jp070106h PG 5 WC Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary SC Chemistry; Science & Technology - Other Topics; Materials Science GA 160PN UT WOS:000245954900057 ER PT J AU Espley, JR Farrell, WM Brain, DA Morgan, DD Cantor, B Plaut, JJ Acuna, MH Picardi, G AF Espley, Jared R. Farrell, William M. Brain, David A. Morgan, David D. Cantor, Bruce Plaut, Jeffrey J. Acuna, Mario H. Picardi, Giovanni TI Absorption of MARSIS radar signals: Solar energetic particles and the daytime ionosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MAGNETIC-FIELD; MARTIAN IONOSPHERE; METEOR-SHOWERS; ATMOSPHERE; VARIABILITY; PREDICTIONS; SOUNDINGS; IMPACT; LAYER; EARTH AB We present observations from the subsurface sounding mode of the MARSIS instrument onboard Mars Express that imply radar wave absorption because of increased amounts of ionization in the upper Martian atmosphere during the fall of 2005. On at least two occasions these radar disruptions lasted for several days and we find that these periods are correlated with periods when other instruments indicate elevated levels of solar energetic particles. Another disruption lasted for over a month and we find that it was likely caused by a combination of solar activity and observing through the daytime ionosphere. There is no evidence in the present results for the constant ionospheric layer predicted to be created by the normal infall of cosmic dust, although the effects of enhanced infall during meteor showers remains uncertain. The effects of dust activity also remain uncertain but will be tested during the 2007 dust season. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Malin Space Sci Syst, San Diego, CA 92191 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Roma La Sapienza, Infocom Dept, I-00184 Rome, Italy. RP Espley, JR (reprint author), NASA, Goddard Space Flight Ctr, Code 695, Greenbelt, MD 20771 USA. EM jared.espley@gsfc.nasa.gov RI Espley, Jared/I-5118-2013; Farrell, William/I-4865-2013 OI Espley, Jared/0000-0002-6371-9683; NR 30 TC 21 Z9 21 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 2 PY 2007 VL 34 IS 9 AR L09101 DI 10.1029/2006GL028829 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 165LB UT WOS:000246305900001 ER PT J AU Holzer, M Hall, TM AF Holzer, Mark Hall, Timothy M. TI Low-level transpacific transport SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NORTHEAST PACIFIC; ASIAN EMISSIONS; AIR-POLLUTION; UNITED-STATES; OZONE; OUTFLOW; TIMESCALES; REANALYSIS; PATHWAYS; O-3 AB The role of low-level transpacific paths in bringing east Asian air to the North American west coast surface is determined using conditional transit-time distributions. These distributions are computed with the MATCH transport model driven by NCEP reanalysis data. Transpacific paths that lie entirely below similar to 2.2 km contribute negligibly to the west coast column burden of east Asian air. However, during summer such paths account for about half of the climatological west coast surface mixing ratio of east Asian air with transit times of less than similar to 3 weeks. Summertime transport is characterized by distinct upper and lower level transport modes, which form by convective injection and boundary layer outflow into a summertime marine troposphere of high stability and weak baroclinicity. During the other seasons the climatological east Asian air plume organizes into distinct midlatitude and subtropical parts, particularly evident during spring and fall. The midlatitude plume is characterized by mixing along sloping isentropes, which transports low-level air aloft over the western Pacific and brings midtropospheric air to the surface over the eastern Pacific. The subtropical part of the plume is formed by convectively injected air. Lagged, weighted composites show that summertime surface events are characterized by strong low-level Asian outflow, while for the other seasons surface events are associated with enhanced mixing along sloping isentropes. C1 Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA. Univ British Columbia, Dept Earth & Ocean Sci, Atmoshper Sci Program, Vancouver, BC V5Z 1M9, Canada. Langara Coll, Dept Phys, Vancouver, BC, Canada. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Holzer, M (reprint author), Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA. EM mholzer@eos.ubc.ca; thall@giss.nasa.gov NR 25 TC 14 Z9 14 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 2 PY 2007 VL 112 IS D9 AR D09103 DI 10.1029/2006JD007828 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 165LH UT WOS:000246306500006 ER PT J AU Xu, JY Liu, HL Yuan, W Smith, AK Roble, RG Mertens, CJ Russell, JM Mlynczak, MG AF Xu, Jiyao Liu, H. L. Yuan, W. Smith, A. K. Roble, R. G. Mertens, C. J. Russell, J. M., III Mlynczak, M. G. TI Mesopause structure from thermosphere, ionosphere, mesosphere, energetics, and dynamics (TIMED)/sounding of the atmosphere using broadband emission radiometry (SABER) observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MIDDLE ATMOSPHERE; THERMAL STRUCTURE; GRAVITY-WAVES; MIDLATITUDE MESOPAUSE; SUMMER MESOSPHERE; TEMPERATURE; LATITUDES; LIDAR; REGION; CLIMATOLOGY AB Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics (TIMED)/Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) temperature observations are used to study the global structure and variability of the mesopause altitude and temperature. There are two distinctly different mesopause altitude levels: the higher level at 95-100 km and the lower level below similar to 86 km. The mesopause of the middle- and high-latitude regions is at the lower altitude in the summer hemisphere for about 120 days around summer solstice and is at the higher altitude during other seasons. At the equator the mesopause is at the higher altitude for all seasons. In addition to the seasonal variation in middle and high latitudes, the mesopause altitude and temperature undergo modulation by diurnal and semidiurnal tides at all latitudes. The mesopause is about 1 km higher at most latitudes and 6-9 K warmer at middle to high latitudes around December solstice than it is around June solstice. These can also be interpreted as hemispheric asymmetry between mesopause altitude and temperature at solstice. Possible causes of the asymmetry as related to solar forcing and gravity wave forcing are discussed. C1 Chinese Acad Sci, State Key Lab Space Weather, Beijing 100080, Peoples R China. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Hampton Univ, Dept Phys, Hampton, VA 23668 USA. RP Xu, JY (reprint author), Chinese Acad Sci, State Key Lab Space Weather, POB 8701, Beijing 100080, Peoples R China. EM liuh@ucar.edu RI Mlynczak, Martin/K-3396-2012; Liu, Han-Li/A-9549-2008 OI Liu, Han-Li/0000-0002-6370-0704 NR 32 TC 46 Z9 47 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 2 PY 2007 VL 112 IS D9 AR D09102 DI 10.1029/2006JD007711 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 165LH UT WOS:000246306500003 ER PT J AU Tu, JN Dhar, M Song, P Reinisch, BW Green, JL Benson, RF Coster, AJ AF Tu, J. N. Dhar, M. Song, P. Reinisch, B. W. Green, J. L. Benson, R. F. Coster, A. J. TI Extreme polar cap density enhancements along magnetic field lines during an intense geomagnetic storm SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID CLEFT ION FOUNTAIN; RADIO PLASMA IMAGER; ELECTRON-DENSITY; EARTHS MAGNETOSPHERE; IONOSPHERIC STORMS; ALTITUDE; RESONANCES; CONVECTION; LATITUDES; FEATURES AB Sounding measurements from the radio plasma imager (RPI) on the IMAGE satellite are used to derive electron number density distributions along magnetic field lines in the polar cap magnetosphere during an intense magnetic storm. It is shown that electron densities along magnetic field lines in the polar cap magnetosphere were greatly enhanced on both the dayside and nightside during the storm, compared to the electron density profiles measured during periods of lower geomagnetic activities. The electron density enhancements were observed extending to 7 Earth radii (R-E) in altitude on the dayside, with the electron density value reaching about 10 cm(-3) at 7 R-E altitude. The observed density enhancements were likely due to the enhanced cleft ion fountain during the storm although some of nightside density enhancements might be caused by the increased ion outflows locally in the polar cap. The strongest electron density enhancements observed on the dayside are possibly further associated with storm-time transport of plasma from the midlatitude ionosphere and plasmasphere to high latitudes, which manifests as a plasma plume intruding to dayside high latitudes as seen from total electron content (TEC) maps. With an enhanced source population supplied by the plasma plume, acceleration and heating processes in the dayside cusp/auroral region may produce a large flux of outflowing plasma along magnetic field lines while the outflowing plasma is convected anti-sunward toward the polar cap. These processes lead to strongly enhanced cleft ion fountain and thus greatly raised electron densities at magnetospheric altitudes in the polar cap. The present study captures an event of a massive redistribution of the magnetospheric and ionospheric plasma during a geomagnetic storm caused by extreme solar wind/interplanetary magnetic field (IMF) conditions. C1 Univ Massachusetts, Ctr Atmospher Res, Lowell, MA 01854 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. MIT, Haystack Observ, Westford, MA 01886 USA. RP Tu, JN (reprint author), Univ Massachusetts, Ctr Atmospher Res, 600 Suffolk St, Lowell, MA 01854 USA. EM jiannan_tu@uml.edu; james.green@nasa.gov; robert.f.benson@nasa.gov; ajc@haystack.mit.edu NR 56 TC 12 Z9 12 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 2 PY 2007 VL 112 IS A5 AR A05201 DI 10.1029/2006JA012034 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 165LZ UT WOS:000246308300001 ER PT J AU Brown, IG Lane, JE Youngquist, RC AF Brown, Ian G. Lane, John E. Youngquist, Robert C. TI A lunar-based spacecraft propulsion concept - The ion beam sail SO ACTA ASTRONAUTICA LA English DT Article DE spacecraft propulsion; ion beam thruster; ion propulsion; interplanetary travel AB We describe a concept for spacecraft propulsion by means of an energetic ion beam, with the ion source fixed at the spacecraft starting point (e.g., a lunar-based ion beam generator) and not onboard the vessel. This approach avoids the substantial mass penalty associated with the onboard ion source and power supply hardware, and vastly more energetic ion beam systems can be entertained. We estimate the ion beam parameters required for various scenarios and consider some of the constraints limiting the concept. We find that the "ion beam sail" approach can be viable and attractive for journey distances not too great, for example, within the Earth-Moon system, and could potentially provide support for journeys to the inner planets. (c) 2006 Elsevier Ltd. All rights reserved. C1 ASRC Aerosp Corp, Kennedy Space Ctr, FL 32815 USA. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. NASA, Kennedy Space Ctr, FL 32899 USA. RP Lane, JE (reprint author), ASRC Aerosp Corp, POB 21087, Kennedy Space Ctr, FL 32815 USA. EM John.Lane-1@ksc.nasa.gov NR 17 TC 2 Z9 2 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAY-JUN PY 2007 VL 60 IS 10-11 BP 834 EP 845 DI 10.1016/j.actaastro.2006.11.003 PG 12 WC Engineering, Aerospace SC Engineering GA 159PB UT WOS:000245877300006 ER PT J AU Landis, GA AF Landis, Geoffrey A. TI Materials refining on the Moon SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 29th IEEE Photovoltaic Specialists Conference CY MAY 19-24, 2002 CL NEW ORLEANS, LA SP IEEE Electr Devices Soc DE Moon; silicon; oxygen; in situ resources; ISRU; refining AB Oxygen, metals, silicon, and glass are raw materials that will be required for long-term habitation and production of structural materials and solar arrays on the Moon. A process sequence is proposed for refining these materials from lunar regolith, consisting of separating the required materials from lunar rock with fluorine. The fluorine is brought to the Moon in the form of potassium fluoride, and is liberated from the salt by electrolysis in a eutectic salt melt. Tetrafluorosilane produced by this process is reduced to silicon by a plasma reduction stage; the fluorine salts are reduced to metals by reaction with metallic potassium. Fluorine is recovered from residual MgF and CaF2 by reaction with K2O. Published by Elsevier Ltd. C1 NASA, John Glenn Res Ctr, Cleveland, OH 44135 USA. RP Landis, GA (reprint author), NASA, John Glenn Res Ctr, Mailstop 302-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. EM geoffrey.a.landis@nasa.gov NR 31 TC 9 Z9 9 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAY-JUN PY 2007 VL 60 IS 10-11 BP 906 EP 915 DI 10.1016/j.actaastro.2006.11.004 PG 10 WC Engineering, Aerospace SC Engineering GA 159PB UT WOS:000245877300014 ER PT J AU Rayman, MD Fraschetti, TC Raymond, CA Russell, CT AF Rayman, Marc D. Fraschetti, Thomas C. Raymond, Carol A. Russell, Christopher T. TI Coupling of system resource margins through the use of electric propulsion: Implications in preparing for the Dawn mission to Ceres and Vesta SO ACTA ASTRONAUTICA LA English DT Article AB The Dawn project is progressing toward its 2007 launch on a mission to orbit main belt asteroids (1) Ceres and (4) Vesta. Designed to provide insights into important questions about the evolution of the solar system, Dawn will spend more than 0.5 years in orbit about each of these bodies. This challenging mission is enabled by an ion propulsion system. In contrast to missions that use conventional chemical propulsion, the use of this system creates a strong coupling of allowable flight system mass and available power, thereby requiring different methods of managing these and other technical resources. Now that the project is nearing launch, the refinement of resource estimates allows the identification of excess margin, which is being applied in novel ways to benefit the project both in development and in operations. (c) 2006 Elsevier Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. RP Rayman, MD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM mrayman@jpl.nasa.gov NR 5 TC 23 Z9 23 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAY-JUN PY 2007 VL 60 IS 10-11 BP 930 EP 938 DI 10.1016/j.actaastro.2006.11.012 PG 9 WC Engineering, Aerospace SC Engineering GA 159PB UT WOS:000245877300016 ER PT J AU Miles, JH AF Miles, Jeffrey Hilton TI Restricted modal analysis applied to internal annular combustor autospectra and cross-spectra measurements SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA/CEAS 12th Aeroacoustics Conference CY MAY 08-10, 2006 CL Cambridge, MA SP Amer Inst Aeronaut & Astronaut, CEAS ID TIME-DELAY ESTIMATION; NOISE SOURCES; DUCTS; FAN; COHERENCE; MODES; PIPE AB A treatment of the modal decomposition of the pressure field in a combustor as determined by two pressure time history measurements is developed herein. It is applied to a Pratt and Whitney PW4098 engine combustor over a range of operating conditions. For modes other than the plane wave the assumption is made that there are distinct frequency bands in which the individual modes, including the plane wave mode, overlap such that if circumferential mode m and circumferential mode m - 1 are present then circumferential mode m - 2 is not. In the analysis used herein at frequencies above the first cutoff mode frequency, only pairs of circumferential modes are individually present at each frequency. Consequently, this is a restricted modal analysis. As part of the analysis one specifies mode cut-on frequencies. This creates a set of frequencies that each mode spans. One finding was the successful use of the same modal span frequencies over a range of operating conditions for this particular engine. This suggests that for this case the cut-on frequencies are in proximity at each operating condition. Consequently, the combustion noise spectrum related to the circumferential modes might not change much with operating condition. C1 NASA, John H Glenn Res Ctr Lewis Field, Acoust Branch, Cleveland, OH 44135 USA. RP Miles, JH (reprint author), NASA, John H Glenn Res Ctr Lewis Field, Acoust Branch, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 52 TC 4 Z9 4 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 2007 VL 45 IS 5 BP 988 EP 999 DI 10.2514/1.25179 PG 12 WC Engineering, Aerospace SC Engineering GA 163WX UT WOS:000246195000004 ER PT J AU Furfaro, R Ganapol, BD Johnson, LF Herwitz, SR AF Furfaro, R. Ganapol, B. D. Johnson, L. F. Herwitz, S. R. TI Neural network algorithm for coffee ripeness evaluation using airborne images SO APPLIED ENGINEERING IN AGRICULTURE LA English DT Article DE remote sensing; neural networks; radiative transfer; model inversion; ripeness evaluation; coffee arabica L ID LEAF-AREA INDEX; RADIATIVE-TRANSFER MODELS; REFLECTANCE MODEL; CANOPY VARIABLES; PLANT CANOPIES; VEGETATION; INVERSION; VALIDATION; SCATTERING; LAI AB A NASA unmanned aerial vehicle (UAV) was deployed over a commercial coffee plantation during the 2002 harvest season. An on-board digital camera system collected a set of high-resolution surface reflectance images in three spectral bands (580, 660, and 790 nm). An intelligent and robust algorithm operated on the multispectral images to estimate absolute percentages of under-ripe (green), ripe (yellow), and over-ripe (brown) coffee cherries displayed on the canopy surface. The procedure was based on a coupled leaf/canopy radiative transfer model (LCM2), modified to include fruiting bodies as photon scattering and absorbing elements. A neural network (NN) set was trained on simulated data, and then used to invert LCM2 for retrieval of fruit and leaf percentages from empirical canopy reflectance data. A projection technique was implemented to systematically mitigate situations where the observed reflectance data fell outside the NN training set domain and the inversion thus initially rendered non-physical solutions (fruit percentages outside of range 0 to 100%). The algorithm was applied to three study fields representing a broad gradient of mature (ripe plus over-ripe) fruit ranging from 28% to 61%. Correlation between predictions and yield data across all ripeness levels was 0.78, with a mean absolute error of 11% (range 1% to 26%). By comparison, a standard ground-based harvest readiness assessment produced a correlation 0.64 with yield, mean absolute error of 13% (range 5% to 23%). The procedure was designed to operate on a reasonably modest set of a priori specifications and, by coupling with remote sensing, potentially represents an efficient method for monitoring ripeness progression or other agricultural phenomena that alter visible and near-infrared crop canopy reflectance. C1 NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. Univ Arizona, Dept Aerosp & Mech Engn, Tucson, AZ 85721 USA. Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. Calif State Univ, Div Sci & Environm Policy, Monterey, CA USA. Clark Univ, Dept Earth Sci, Worcester, MA 01610 USA. NASA, UAV Applicat Ctr, Moffett Field, CA USA. RP Johnson, LF (reprint author), NASA, Ames Res Ctr, Div Earth Sci, MS242-4, Moffett Field, CA 94035 USA. EM Ljohnson@mail.arc.nasa.gov NR 38 TC 6 Z9 6 U1 0 U2 11 PU AMER SOC AGRICULTURAL & BIOLOGICAL ENGINEERS PI ST JOSEPH PA 2950 NILES RD, ST JOSEPH, MI 49085-9659 USA SN 0883-8542 J9 APPL ENG AGRIC JI Appl. Eng. Agric. PD MAY PY 2007 VL 23 IS 3 BP 379 EP 387 PG 9 WC Agricultural Engineering SC Agriculture GA 180BY UT WOS:000247336100017 ER PT J AU Ulvestad, JS Johnson, KE Neff, SG AF Ulvestad, James S. Johnson, Kelsey E. Neff, Susan G. TI A VLBI search for radio supernovae in Wolf-Rayet galaxies SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual ( II Zw 40, He 2-10, NGC 5253); galaxies : starburst; radio continuum : galaxies ID H II REGIONS; STAR-FORMATION; HENIZE 2-10; STARBURST GALAXIES; NGC 5253; EMISSION; NGC-5253; CLUSTERS; SPECTROPHOTOMETRY; DISTRIBUTIONS AB We have used the VLBI High-Sensitivity Array (VLBA with Very Large Array [VLA], Green Bank Telescope, and Arecibo) to search for young radio supernovae in three nearby Wolf-Rayet dwarf galaxies containing super star clusters and signs of extreme star formation in the last few million years. No milliarcsecond radio sources were detected in II Zw 40, He 2-10, or NGC 5253, implying that these galaxies contain few radio supernovae, despite the fact that they have at least some star formation going back to 10 million years ago. The upper limits of the source powers range from similar to 6 x 10(17) to similar to 2 x 10(18) W Hz(-1) at 5 GHz, roughly 0.6-2.2 times the power of the Galactic supernova remnant Cassiopeia A. Comparison with the radio supernova population in Arp 299 implies that the current supernova rates in the three dwarf galaxies are below 10(-2) yr(-1), consistent with standard star formation models that predict supernova rates of 10(-3) yr(-1) or less in our targets. In He 2-10, the VLBI nondetection of a compact VLA source with a significant nonthermal component indicates that this source may be dominated by one or more supernova remnants with ages of a few hundred years or more, which are comparable to Cas A in power and size. C1 Natl Radio Astron Observ, Socorro, NM 87801 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20775 USA. RP Ulvestad, JS (reprint author), Natl Radio Astron Observ, Socorro, NM 87801 USA. EM julvesta@nrao.edu; kej7a@virginia.edu; susan.neff@gsfc.nasa.gov OI Ulvestad, James/0000-0002-9362-7237 NR 48 TC 9 Z9 9 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2007 VL 133 IS 5 BP 1868 EP 1873 DI 10.1086/512190 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 165XY UT WOS:000246342200003 ER PT J AU Konopacky, QM Ghez, AM Duchene, G McCabe, C MacIntosh, BA AF Konopacky, Q. M. Ghez, A. M. Duchene, G. McCabe, C. MacIntosh, B. A. TI Measuring the mass of a pre-main-sequence binary star through the orbit of TWA 5A SO ASTRONOMICAL JOURNAL LA English DT Article DE binaries : visual; stars : fundamental parameters; stars : individual (TWA 5A); stars : pre-main-sequence ID T-TAURI STARS; HYDRAE ASSOCIATION; YOUNG STARS; EVOLUTIONARY TRACKS; CLUSTER; MEMBERS; TELESCOPE; SYSTEMS; IMAGES AB We present the results of a 5 yr monitoring campaign of the close binary TWA 5Aab in the TW Hydrae association, using speckle and adaptive optics on the W. M. Keck 10 m telescopes. These measurements were taken as part of our ongoing monitoring of pre-main-sequence (PMS) binaries in an effort to increase the number of dynamically determined PMS masses and thereby calibrate the theoretical PMS evolutionary tracks. Our observations have allowed us to obtain the first determination of this system's astrometric orbit. We find an orbital period of 5.94 +/- 0.09 yr and a semimajor axis of 0.066 '' +/- 0.005 ''. Combining these results with a kinematic distance, we calculate a total mass of 0.71 +/- 0.14 M(circle dot) (D/44 pc)(3) for this system. This mass measurement, as well as the estimated age of this system, is consistent to within 2 sigma of all theoretical models considered. In this analysis we properly account for correlated uncertainties, and we show that while these correlations are generally ignored, they increase the formal uncertainties by up to a factor of 5 and therefore are important to incorporate. With only a few more years of observation, this type of measurement will allow the theoretical models to be distinguished. C1 Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. Univ Grenoble 1, Observ Grenoble, Astrophys Lab, F-38041 Grenoble 9, France. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94551 USA. RP Konopacky, QM (reprint author), Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA. EM quinn@astro.ucla.edu; ghez@astro.ucla.edu; gaspard.duchene@obs.ujf-grenoble.fr; mccabe@jpl.nasa.gov; bmac@igpp.ucllnl.org NR 34 TC 26 Z9 26 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2007 VL 133 IS 5 BP 2008 EP 2014 DI 10.1086/513010 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 165XY UT WOS:000246342200017 ER PT J AU Doering, RL Meixner, M Holfeltz, ST Krist, JE Ardila, DR Kamp, I Clampin, MC Lubow, SH AF Doering, R. L. Meixner, M. Holfeltz, S. T. Krist, J. E. Ardila, D. R. Kamp, I. Clampin, M. C. Lubow, S. H. TI HD 97048's circumstellar environment as revealed by a Hubble Space Telescope acs coronagraphic study of disk candidate stars SO ASTRONOMICAL JOURNAL LA English DT Article DE circumstellar matter; stars : individual (HD 34282, HD 97048, HD 139450; HD 158643, HD 159492, HD 195627) ID HERBIG-AE/BE STARS; MAIN-SEQUENCE STARS; VEGA-LIKE SYSTEMS; MILLIMETER-WAVE PROPERTIES; AE STAR; IMAGING SPECTROGRAPH; PLANETARY SYSTEMS; DEBRIS DISK; 51 OPH; DUST AB We present the results of a coronagraphic scattered-light imaging survey of six young disk candidate stars using the Hubble Space Telescope Advanced Camera for Surveys. The observations made use of the 1.8'' occulting spot through the F606W (broad V) filter. Circumstellar material was imaged around HD 97048, a Herbig Ae/Be star located in the Chamaeleon I dark cloud at a distance of 180 pc. The material is seen between similar to 2'' (360 AU) and similar to 4'' (720 AU) from the star in all directions. A V-band azimuthally averaged radial surface brightness profile peaks at r = 200 with a value of 19: 6 +/- 0: 2 mag arcsec(-2) and smoothly decreases with projected distance from the star as I proportional to r(-3.3 +/- 0.5). An integrated flux of 16: 8 +/- 0: 1 mag is measured between 200 and 400, corresponding to a scattered-light fractional luminosity lower limit of L-sca/L-* > 8.4 x 10(-4). Filamentary structure resembling spiral arms similar to that seen in Herbig Ae/Be disks is observed. Such structure has been attributed to the influence of orbiting planets or stellar encounters. Average surface brightness upper limits are determined for the five nondetections: HD 34282, HD 139450, HD 158643, HD 159492, and HD 195627. Possible reasons for the nondetections are disks that are too faint or disks hidden by the occulter. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. Space Telescope Sci Inst, Space Telescope Div, Baltimore, MD USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Doering, RL (reprint author), Univ Illinois, Dept Phys, Urbana, IL 61801 USA. RI Clampin, mark/D-2738-2012 NR 56 TC 18 Z9 18 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2007 VL 133 IS 5 BP 2122 EP 2131 DI 10.1086/512610 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 165XY UT WOS:000246342200026 ER PT J AU De Propris, R Stanford, SA Eisenhardt, PR Holden, BP Rosati, P AF De Propris, Roberto Stanford, S. A. Eisenhardt, Peter R. Holden, Brad P. Rosati, Piero TI The rest-frame K-band luminosity function of galaxies in clusters to z=1.3 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : formation; galaxies : luminosity function, mass function ID COLOR-MAGNITUDE RELATION; HIGH-REDSHIFT CLUSTERS; SPITZER-SPACE-TELESCOPE; FUNDAMENTAL-PLANE; STELLAR MASS; RED GALAXIES; ELLIPTIC GALAXIES; STAR-FORMATION; COMA CLUSTER; QSO SURVEY AB We derive the rest-frame K-band luminosity function for galaxies in 32 clusters at 0: 6 < z < 1: 3 using deep 3.6 and 4.5 mu m imaging from the Spitzer Space Telescope Infrared Array Camera. The luminosity functions approximate the stellar mass function of the cluster galaxies. Their dependence on redshift indicates that massive cluster galaxies ( to the characteristic luminosityM(K)(*)) are fully assembled at least at z similar to 1.3 and that little significant accretion takes place at later times. The existence of massive, highly evolved galaxies at these epochs is likely to represent a significant challenge to theories of hierarchical structure formation where such objects are formed by the late accretion of spheroidal systems at z < 1. C1 Cerro Tololo Interamer Observ, La Serena, Chile. Univ Bristol, Dept Phys, Bristol BS8 1TL, Avon, England. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95604 USA. European So Observ, D-85748 Garching, Germany. RP De Propris, R (reprint author), Cerro Tololo Interamer Observ, La Serena, Chile. NR 70 TC 38 Z9 38 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2007 VL 133 IS 5 BP 2209 EP 2215 DI 10.1086/513516 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 165XY UT WOS:000246342200034 ER PT J AU Grupe, D Nousek, JA Vanden Berk, DE Roming, PWA Burrows, DN Godet, O Osborne, J Gehrels, N AF Grupe, Dirk Nousek, John A. Vanden Berk, Daniel E. Roming, Peter W. A. Burrows, David N. Godet, Olivier Osborne, Julian Gehrels, Neil TI Redshift filtering by Swift apparent X-ray column density SO ASTRONOMICAL JOURNAL LA English DT Article DE distance scale; gamma rays : bursts ID BURST AFTERGLOWS; ABSORPTION; TELESCOPE; EVOLUTION; GALAXY AB We remark on the utility of an observational relation between the absorption column density in excess of the Galactic absorption column density, triangle N-H = N-H,N-fit,N- - N-H,N-gal, and redshift, z, determined from all 55 Swift-observed long bursts with spectroscopic redshifts as of 2006 December. The absorption column densities, NH; Bt, are determined from power-law fits to the X-ray spectra with the absorption column density left as a free parameter. We find that higher excess absorption column densities with triangle N-H > 2 x 10(21) cm(-2) are only present in bursts with redshifts z < 2. Low absorption column densities with triangle NH < 1 x 10(21) cm(-2) appear preferentially in high-redshift bursts. Our interpretation is that this relation between redshift and excess column density is an observational effect resulting from the shift of the source rest-frame energy range below 1 keV out of the X-ray Telescope observable energy range for high-redshift bursts. We find a clear anticorrelation between triangle N-H and z that can be used to estimate the range of the maximum redshift of an afterglow. A critical application of our finding is that rapid X-ray observations can be used to optimize the instrumentation used for ground-based optical/near-IR follow-up observations. Ground-based spectroscopic redshift measurements of as many bursts as possible are crucial for gamma-ray burst science. C1 Penn State Univ, Dept Astron, University Pk, PA 16802 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. NASA, Goddard Space Flight Ctr, Astrophys Phys Lab, AStrophys Sci Div, Greenbelt, MD 20771 USA. RP Grupe, D (reprint author), Penn State Univ, Dept Astron, University Pk, PA 16802 USA. EM grupe@astro.psu.edu RI Gehrels, Neil/D-2971-2012 NR 78 TC 40 Z9 40 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2007 VL 133 IS 5 BP 2216 EP 2221 DI 10.1086/513014 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 165XY UT WOS:000246342200035 ER PT J AU Piner, BG Mahmud, M Fey, AL Gospodinova, K AF Piner, B. G. Mahmud, M. Fey, A. L. Gospodinova, K. TI Relativistic jets in the radio reference frame image database. I. Apparent speeds from the first 5 years of data SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : jets; radio continuum : galaxies ID ACTIVE GALACTIC NUCLEI; LONG-BASELINE INTERFEROMETRY; GAMMA-RAY SOURCES; SUPERLUMINAL MOTION; VLBA OBSERVATIONS; ASTROMETRIC SUITABILITY; SCALE STRUCTURE; LINE ARRAY; QUASARS; STATISTICS AB We present the results of an analysis of relativistic jet apparent speeds from VLBI images in the Radio Reference Frame Image Database (RRFID). The images are snapshot VLBI images at 8 and 2 GHz using the VLBA, plus up to 10 additional antennas that provide global VLBI coverage. We have analyzed the 8 GHz images from the first 5 years of the database (1994-1998), for all sources observed at three or more epochs during this time range. This subset comprises 966 images of 87 sources. The sources in this subset have an average of 11 epochs of observation over the years 1994-1998, with the best-observed sources having 19 epochs. About half of the sources in this RRFID kinematic survey have not been previously studied with multiepoch VLBI observations. We have measured apparent speeds for a total of 184 jet components in 77 sources, of which the best-measured 94 component speeds in 54 sources are used in the final analysis. The apparent speed distribution shows a peak at low apparent speeds (consistent with stationary components), a tail extending out to apparent speeds of about 30c, and a mean apparent speed of 3.6c. A total of 36 of the sources in this paper are also included in the 2 cm VLBA survey by Kellermann et al., with similar angular resolution, sensitivity, and time range. For those sources, we present a detailed component-by-component comparison of the apparent speeds measured by the 2 cm survey and those measured in this paper. Many of the independent apparent speed measurements agree very well, but for approximately 25% of the components we find significant differences in the apparent speeds measured by the two surveys. The leading cause of these discrepancies is differences in how the two surveys have identified jet components from epoch to epoch. C1 Whittier Coll, Dept Phys & Astron, Whittier, CA 90608 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Coll Cork, Dept Phys, Cork, Ireland. USN Observ, Washington, DC 20392 USA. RP Piner, BG (reprint author), Whittier Coll, Dept Phys & Astron, Whittier, CA 90608 USA. EM gpiner@whittier.edu NR 39 TC 43 Z9 43 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2007 VL 133 IS 5 BP 2357 EP 2388 DI 10.1086/514812 PG 32 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 165XY UT WOS:000246342200046 ER PT J AU Gary, GA Pietraszewski, C West, EA Dines, TC AF Gary, G. A. Pietraszewski, C. West, E. A. Dines, T. C. TI Solar confocal interferometers for sub-picometer-resolution spectral filters SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE Sun : atmosphere; instrumentation : interferometers; Sun : magnetic fields; Sun : general; Sun : infrared ID TELESCOPE; SUNSPOT AB Aims. The confocal Fabry-Perot interferometer allows sub-picometer spectral resolution of Fraunhofer line profiles. Such high spectral resolution is needed to keep pace with the higher spatial resolution of the new set of large-aperture solar telescopes. The line-of-sight spatial resolution derived for line profile inversions would then track the improvements of the transverse spatial scale provided by the larger apertures. In particular, profile inversion allows improved velocity and magnetic field gradients to be determined independent of multiple line analysis using different energy levels and ions. The confocal interferometer's unique properties allow a simultaneous increase in both etendue and spectral power. The higher throughput for the interferometer provides significant decrease in the aperture, which is important in spaceflight considerations. Methods. We have constructed and tested two confocal interferometers. A slow-response thermal-controlled interferometer provides a stable system for laboratory investigation, while a piezoelectric interferometer provides a rapid response for solar observations. Results. In this paper we provide design parameters, show construction details, and report on the laboratory test for these interferometers. The field of view versus aperture for confocal interferometers is compared with other types of spectral imaging filters. We propose a multiple etalon system for observing with these units using existing planar interferometers as pre-filters. The radiometry for these tests established that high spectral resolution profiles can be obtained with imaging confocal interferometers. These sub-picometer spectral data of the photosphere in both the visible and near-infrared can provide important height variation information. However, at the diffraction-limited spatial resolution of the telescope, the spectral data is photon starved due to the decreased spectral passband. C1 NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35812 USA. IC Opt Syst Ltd, Beckenham BR3 4TW, Kent, England. RP Gary, GA (reprint author), NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35812 USA. EM Allen.Gary@nasa.gov; sales@icopticalsytems.com NR 27 TC 1 Z9 1 U1 1 U2 2 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2007 VL 467 IS 1 BP 375 EP 383 DI 10.1051/0004-6361:20066287 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 166YU UT WOS:000246417900042 ER PT J AU Tramacere, A Giommi, P Massaro, E Perri, M Nesci, R Colafrancesco, S Tagliaferri, G Chincarini, G Falcone, A Burrows, DN Roming, P Chester, MM Gehrels, N AF Tramacere, A. Giommi, P. Massaro, E. Perri, M. Nesci, R. Colafrancesco, S. Tagliaferri, G. Chincarini, G. Falcone, A. Burrows, D. N. Roming, P. Chester, M. McMath Gehrels, N. TI SWIFT observations of TeVBL Lacertae objects SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE radiation mechanisms : non-thermal; galaxies : BL Lacertae objects : general; X-rays : galaxies ID EXTRAGALACTIC BACKGROUND LIGHT; LOG-PARABOLIC SPECTRA; X-RAY-SPECTRA; ACTIVE GALAXY MARKARIAN-421; ENERGY GAMMA-RAYS; BL-LAC OBJECTS; MULTIWAVELENGTH OBSERVATIONS; PARTICLE-ACCELERATION; 1ES 2344+514; PKS 2155-304 AB Context. We present the results of a set of observations of nine TeV detected BL Lac objects performed by the XRT and UVOT detectors on board the Swift satellite between March and December 2005. Aims. Our main goal is the accurate measurement of the spectral shape of TeV detected BL Lacs. Particular attention was given to the presence of intrinsic spectral curvature in the X-ray band. Methods. To perform our X-ray spectral analysis we have assumed either a log-parabolic or a simple power-law model. Results. The X-ray data of many objects in our sample clearly show highly significant spectral curvature. However, in sources with spectral energy distribution peaked at energies lower than similar to 0.1 keV the X-ray spectrum is steep and generally consistent with a power law. In most of these cases poor statistics did not allow us to obtain tight constraints on the spectral curvature. We have used UVOT observations to verify if X-ray spectra can be extrapolated to lower frequencies and to search for multiple emission components. Conclusions. The results of our analysis are useful for the study of possible signatures of statistical acceleration processes predicting intrinsically curved spectra and for modelling the SED of BL Lacertae objects up to TeV energies where a corresponding curvature is likely to be present. C1 Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. ESRIN, ASI Sco Data Ctr, I-00044 Frascati, Italy. Osserv Astron Roma, INAF, I-00040 Monte Porzio Catone, Italy. Osserv Astron Brera, INAF, I-23807 Merate, Italy. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tramacere, A (reprint author), Univ Roma La Sapienza, Dipartimento Fis, Piazzale A Moro 2, I-00185 Rome, Italy. EM paolo.giommi@asdc.asi.it RI Gehrels, Neil/D-2971-2012; OI giommi, paolo/0000-0002-2265-5003; Perri, Matteo/0000-0003-3613-4409; Tramacere, Andrea/0000-0002-8186-3793; Tagliaferri, Gianpiero/0000-0003-0121-0723 NR 48 TC 47 Z9 47 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2007 VL 467 IS 2 BP 501 EP 508 DI 10.1051/0004-6361:20066226 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 167BF UT WOS:000246424900015 ER PT J AU Churazov, E Sunyaev, R Revnivtsev, M Sazonov, S Molkov, S Grebenev, S Winkler, C Parmar, A Bazzano, A Falanga, M Gros, A Lebrun, F Natalucci, L Ubertini, P Roques, JP Bouchet, L Jourdain, E Knodlseder, J Diehl, R Budtz-Jorgensen, C Brandt, S Lund, N Westergaard, NJ Neronov, A Turler, M Chernyakova, M Walter, R Produit, N Mowlavi, N Mas-Hesse, JM Domingo, A Gehrels, N Kuulkers, E Kretschmar, P Schmidt, M AF Churazov, E. Sunyaev, R. Revnivtsev, M. Sazonov, S. Molkov, S. Grebenev, S. Winkler, C. Parmar, A. Bazzano, A. Falanga, M. Gros, A. Lebrun, F. Natalucci, L. Ubertini, P. Roques, J.-P. Bouchet, L. Jourdain, E. Knoedlseder, J. Diehl, R. Budtz-Jorgensen, C. Brandt, S. Lund, N. Westergaard, N. J. Neronov, A. Tuerler, M. Chernyakova, M. Walter, R. Produit, N. Mowlavi, N. Mas-Hesse, J. M. Domingo, A. Gehrels, N. Kuulkers, E. Kretschmar, P. Schmidt, M. TI INTEGRAL observations of the cosmic X-ray background in the 5-100 keV range via occultation by the Earth SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE X-rays : diffuse background; X-rays : general; Earth; galaxies : active ID CRAB-NEBULA; GAMMA-RADIATION; GALACTIC RIDGE; SPECTRUM; EMISSION; FLUCTUATIONS; CALIBRATION; REFLECTION; CHANDRA; ORIGIN AB Aims. We study the spectrum of the cosmic X-ray background (CXB) in energy range similar to 5-100 keV. Methods. Early in 2006 the INTEGRAL observatory performed a series of four 30 ks observations with the Earth disk crossing the field of view of the instruments. The modulation of the aperture flux due to occultation of extragalactic objects by the Earth disk was used to obtain the spectrum of the Cosmic X-ray Background ( CXB). Various sources of contamination were evaluated, including compact sources, Galactic Ridge emission, CXB reflection by the Earth atmosphere, cosmic ray induced emission by the Earth atmosphere and the Earth auroral emission. Results. The spectrum of the cosmic X-ray background in the energy band 5-100 keV is obtained. The shape of the spectrum is consistent with that obtained previously by the HEAO-1 observatory, while the normalization is similar to 10% higher. This difference in normalization can ( at least partly) be traced to the different assumptions on the absolute flux from the Crab Nebulae. The increase relative to the earlier adopted value of the absolute flux of the CXB near the energy of maximum luminosity (20-50 keV) has direct implications for the energy release of supermassive black holes in the Universe and their growth at the epoch of the CXB origin. C1 Russian Acad Sci, Space Res Inst, Moscow 117997, Russia. Max Planck Inst Astrophys, D-85740 Garching, Germany. ESA, ESTEC SCISA, NL-2201 AZ Noordwijk, Netherlands. INAF, IASF, I-00133 Rome, Italy. CEA, DAPNIA, DSM, Serv Astrophys, F-91191 Gif Sur Yvette, France. APC UMR 7164, F-75231 Paris, France. UPS, CNRS, Ctr Etud Spatiale Rayonnements, F-31028 Toulouse 4, France. Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. Danish Natl Space Ctr, DK-2100 Copenhagen, Denmark. INTEGRAL Sci Data Ctr, CH-1290 Versoix, Switzerland. CSIC, INTA, Ctr Astrobiol, Madrid 28080, Spain. INTA, LAEFF, Madrid 28080, Spain. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. ESA, ESAC, ISOC, Madrid 28080, Spain. ESA, ESOC, Mission Operat Dept, D-64293 Darmstadt, Germany. RP Churazov, E (reprint author), Russian Acad Sci, Space Res Inst, Profsoyuznaya 84-32, Moscow 117997, Russia. RI Gehrels, Neil/D-2971-2012; Churazov, Eugene/A-7783-2013; Mas-Hesse, J. Miguel /K-6805-2014; Domingo, Albert/L-9071-2014; OI Mas-Hesse, J. Miguel /0000-0002-8823-9723; Domingo, Albert/0000-0001-9764-6411; Parmar, Arvind/0000-0002-3307-6517; Kretschmar, Peter/0000-0001-9840-2048; Bazzano, Angela/0000-0002-2017-4396 NR 52 TC 92 Z9 93 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2007 VL 467 IS 2 BP 529 EP 540 DI 10.1051/0004-6361:20066230 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 167BF UT WOS:000246424900018 ER PT J AU Bodaghee, A Courvoisier, TJL Rodriguez, J Beckmann, V Produit, N Hannikainen, D Kuulkers, E Willis, DR Wendt, G AF Bodaghee, A. Courvoisier, T. J. -L. Rodriguez, J. Beckmann, V. Produit, N. Hannikainen, D. Kuulkers, E. Willis, D. R. Wendt, G. TI A description of sources detected by INTEGRAL during the first 4 years of observations SO ASTRONOMY & ASTROPHYSICS LA English DT Review DE gamma rays : observations; catalogs; X-rays : binaries; Galaxy : stellar content ID X-RAY PULSAR; XMM-NEWTON OBSERVATIONS; ACTIVE GALACTIC NUCLEI; BROAD-BAND SPECTRUM; SEYFERT 1 GALAXY; ALL-SKY SURVEY; ACCRETING MILLISECOND PULSAR; TIMING-EXPLORER OBSERVATIONS; BLACK-HOLE CANDIDATES; TRANSMISSION GRATING SPECTRUM AB Context. In its first 4 years of observing the sky above 20 keV, INTEGRAL-ISGRI has detected 500 sources, around half of which are new or unknown at these energies. Follow-up observations at other wavelengths revealed that some of these sources feature unusually large column densities, long pulsations, and other interesting characteristics. Aims. We investigate where new and previously-known sources detected by ISGRI fit in the parameter space of high-energy objects, and we use the parameters to test correlations expected from theoretical predictions. For example, the influence of the local absorbing matter on periodic modulations is studied for Galactic High-Mass X-ray Binaries (HMXBs) with OB supergiant and Be companions. We examine the spatial distribution of different types of sources in the Milky Way using various projections of the Galactic plane, in order to highlight signatures of stellar evolution and to speculate on the origin of the group of sources whose classifications are still uncertain. Methods. Parameters that are available in the literature, such as positions, photoelectric absorption (N-H), spin and orbital periods, and distances or redshifts, were collected for all sources detected by ISGRI. These values and their references are provided online. Results. ISGRI has detected similar numbers of X-ray Binaries and Active Galactic Nuclei (AGN). The former group contains new members of the class of HMXBs with supergiant stellar companions. Usually, this type of object presents strong intrinsic absorption which leads to a peak emission in an energy range that ISGRI is ideally suited to detect. Thanks to these additional systems, we are able to show that HMXBs are generally segregated in plots of intrinsic N-H versus the orbital period of the system and versus the spin period of the pulsar, based on whether the companion is a Be or an OB supergiant star. We also find a tentative but expected anticorrelation between N-H and the orbital period, and a possible and unexpected correlation between the N-H and the spin period. While only a handful of new Low-Mass X-ray Binaries (LMXBs) have been discovered, there are many sources that remain unclassified and they appear to follow a spatial distribution typical of Galactic sources ( especially LMXBs) rather than extragalactic sources. C1 INTEGRAL Sci Data Ctr, CH-1290 Versoix, Switzerland. Univ Geneva, Astron Observ, CH-1290 Sauverny, Switzerland. CEA Saclay, DSM, DAPNIA, SAp, F-91191 Gif Sur Yvette, France. NASA, Goddard Space Flight Ctr, Astrophys Sci Div, Greenbelt, MD 20771 USA. Univ Helsinki, Observ, FIN-00014 Helsinki, Finland. ESA, ESAC, ISOC, Madrid 28080, Spain. RP Bodaghee, A (reprint author), INTEGRAL Sci Data Ctr, Chemin Ecogia 16, CH-1290 Versoix, Switzerland. EM arash.bodaghee@obs.unige.ch OI Rodriguez, Jerome/0000-0002-4151-4468 NR 553 TC 71 Z9 72 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2007 VL 467 IS 2 BP 585 EP U140 DI 10.1051/0004-6361:20077091 PG 34 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 167BF UT WOS:000246424900022 ER PT J AU D'Elia, V Fiore, F Meurs, EJA Chincarini, G Melandri, A Norci, L Pellizza, L Perna, R Piranomonte, S Sbordone, L Stella, L Tagliaferri, G Vergani, SD Ward, P Angelini, L Antonelli, LA Burrows, DN Campana, S Capalbi, M Cimatti, A Costa, E Cusumano, G Della Valle, M Filliatre, P Fontana, A Frontera, F Fugazza, D Gehrels, N Giannini, T Giommi, P Goldoni, P Guetta, D Israel, G Lazzati, D Malesani, D Marconi, G Mason, K Mereghetti, S Mirabel, F Molinari, E Moretti, A Nousek, J Perri, M Piro, L Stratta, G Testa, V Vietri, M AF D'Elia, V. Fiore, F. Meurs, E. J. A. Chincarini, G. Melandri, A. Norci, L. Pellizza, L. Perna, R. Piranomonte, S. Sbordone, L. Stella, L. Tagliaferri, G. Vergani, S. D. Ward, P. Angelini, L. Antonelli, L. A. Burrows, D. N. Campana, S. Capalbi, M. Cimatti, A. Costa, E. Cusumano, G. Della Valle, M. Filliatre, P. Fontana, A. Frontera, F. Fugazza, D. Gehrels, N. Giannini, T. Giommi, P. Goldoni, P. Guetta, D. Israel, G. Lazzati, D. Malesani, D. Marconi, G. Mason, K. Mereghetti, S. Mirabel, F. Molinari, E. Moretti, A. Nousek, J. Perri, M. Piro, L. Stratta, G. Testa, V. Vietri, M. TI UVES/VLT high resolution spectroscopy of GRB 050730 afterglow: probing the features of the GRB environment SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma rays : bursts; cosmology : observations; Galaxy : abundances; galaxies : ISM; line : identification; line : profiles ID GAMMA-RAY BURST; TIME-DEPENDENT PHOTOIONIZATION; DEEP DEEP SURVEY; PHOTOCHEMICAL EVOLUTION; PHYSICAL CONDITIONS; ELLIPTIC GALAXIES; ABSORPTION-LINES; HIGH-REDSHIFT; DUSTY MEDIUM; METALLICITY AB Aims. The aim of this paper is to study the Gamma Ray Burst (GRB) environment through the analysis of the optical absorption features due to the gas surrounding the GRB. Methods. To this purpose we analyze high resolution spectroscopic observations (R = 20000-45000, corresponding to 14 km s(-1) at 4200 angstrom and 6.6 km s(-1) at 9000 angstrom) of the optical afterglow of GRB050730, obtained with UVES@VLT similar to 4 h after the GRB trigger. Results. The spectrum shows that the ISM of the GRB host galaxy at z = 3.967 is complex, with at least five components contributing to the main absorption system. We detect strong CII*, SiII*, OI* and FeII* fine structure absorption lines associated to the second and third component. Conclusions. For the first three components we derive information on the relative distance from the site of the GRB explosion. Component 1, which has the longest wavelength, highest positive velocity shift, does not present any fine structure nor low ionization lines; it only shows very high ionization features, such as CIV and OVI, suggesting that this component is very close to the GRB site. From the analysis of low and high ionization lines and fine structure lines, we find evidences that the distance of component 2 from the site of the GRB explosion is 10-100 times smaller than that of component 3. We evaluated the mean metallicity of the z = 3.967 system obtaining values approximate to 10(-2) of the solar metallicity or less. However, this should not be taken as representative of the circumburst medium, since the main contribution to the hydrogen column density comes from the outer regions of the galaxy while that of the other elements presumably comes from the ISM closer to the GRB site. Furthermore, difficulties in evaluating dust depletion correction can modify significantly these values. The mean [C/Fe] ratio agrees well with that expected by single star-formation event models. Interestingly the [C/Fe] of component 2 is smaller than that of component 3, in agreement with GRB dust destruction scenarios, if component 2 is closer than component 3 to the GRB site. C1 INAF, Osservatorio Astron Roma, I-00044 Frascati, Italy. Dunsink Observ, Dublin 15, Ireland. INAF, Osservatorio Astron Brera, I-23807 Merate, LC, Italy. Univ Milano Bicocca, I-20126 Milan, Italy. Liverpool John Moores Univ, Astron Res Inst, Birkenhead, Merseyside, England. Dublin City Univ, Sch Phys Sci, Dublin 9, Ireland. Dublin City Univ, NCPST, Dublin 9, Ireland. CEA Saclay, DSM, DAPNIA, Serv Astrophys, F-91191 Gif Sur Yvette, France. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. ASI Sci Data Ctr, I-00044 Frascati, Roma, Italy. INAF, Osservatorio Astrofis Arcetri, I-50125 Florence, Italy. INAF Roma, I-00133 Rome, Italy. INAF, Ist Astrofis Spaziale & Fis Cosm Palermo, I-90146 Palermo, Italy. Univ Ferrara, I-44100 Ferrara, Italy. UMR 7164, F-75231 Paris, France. Int Sch Adv Phys, I-34014 Trieste, Italy. European So Observ, Santiago 19, Chile. PPARC, Swindon SN2 15Z, Wilts, England. INAF, Ist Astrofis Spaziale & Fis Cosm, I-20133 Milan, Italy. European So Observ Vitacura, Santiago 19, Chile. Scuola Normale Super Pisa, I-56126 Pisa, Italy. RP D'Elia, V (reprint author), INAF, Osservatorio Astron Roma, Via Frascati 33, I-00044 Frascati, Italy. RI Gehrels, Neil/D-2971-2012; PIRO, LUIGI/E-4954-2013; Stratta, Maria Giuliana/L-3045-2016; OI moretti, alberto/0000-0002-9770-0315; PIRO, LUIGI/0000-0003-4159-3984; Stratta, Maria Giuliana/0000-0003-1055-7980; D'Elia, Valerio/0000-0002-7320-5862; guetta, dafne/0000-0002-7349-1109; Della Valle, Massimo/0000-0003-3142-5020; Costa, Enrico/0000-0003-4925-8523; Molinari, Emilio/0000-0002-1742-7735; giommi, paolo/0000-0002-2265-5003; Cusumano, Giancarlo/0000-0002-8151-1990; MEREGHETTI, SANDRO/0000-0003-3259-7801; Israel, GianLuca/0000-0001-5480-6438; Perri, Matteo/0000-0003-3613-4409; Giannini, Teresa/0000-0002-0224-096X; fontana, adriano/0000-0003-3820-2823; Tagliaferri, Gianpiero/0000-0003-0121-0723; Testa, Vincenzo/0000-0003-1033-1340; Fiore, Fabrizio/0000-0002-4031-4157 NR 33 TC 37 Z9 37 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2007 VL 467 IS 2 BP 629 EP 639 DI 10.1051/0004-6361:20066479 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 167BF UT WOS:000246424900026 ER PT J AU Ashdown, MAJ Baccigalupi, C Balbi, A Bartlett, JG Borrill, J Cantalupo, C de Gasperis, G Gorski, KM Hivon, E Keihanen, E Kurki-Suonio, H Lawrence, CR Natoli, P Poutanen, T Prunet, S Reinecke, M Stompor, R Wandelt, B AF Ashdown, M. A. J. Baccigalupi, C. Balbi, A. Bartlett, J. G. Borrill, J. Cantalupo, C. de Gasperis, G. Gorski, K. M. Hivon, E. Keihanen, E. Kurki-Suonio, H. Lawrence, C. R. Natoli, P. Poutanen, T. Prunet, S. Reinecke, M. Stompor, R. Wandelt, B. CA Planck CTP Working Grp TI Making sky maps from Planck data SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE cosmology : cosmic microwave background; methods : data analysis ID SCANNING STRATEGY; MAKING ALGORITHM; CMB EXPERIMENTS; 1/F NOISE; MICROWAVE; SURVEYOR AB Aims. We compare the performance of multiple codes written by different groups for making polarized maps from Planck-sized, all-sky cosmic microwave background (CMB) data. Three of the codes are based on a destriping algorithm; the other three are implementations of an optimal maximum-likelihood algorithm. Methods. Time-ordered data (TOD) were simulated using the Planck Level-S simulation pipeline. Several cases of temperature-only data were run to test that the codes could handle large datasets, and to explore effects such as the precision of the pointing data. Based on these preliminary results, TOD were generated for a set of four 217 GHz detectors (the minimum number required to produce I, Q, and U maps) under two different scanning strategies, with and without noise. Results. Following correction of various problems revealed by the early simulation, all codes were able to handle the large data volume that Planck will produce. Differences in maps produced are small but noticeable; differences in computing resources are large. C1 Univ Cambridge, Cavendish Lab, Astrophys Grp, Cambridge CB3 0HE, England. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Univ Heidelberg, Inst Theoret Astrophys, D-69120 Heidelberg, Germany. Ist Nazl Fis Nucl, Sez Trieste, I-34127 Trieste, Italy. SISSA, ISAS, I-34014 Trieste, Italy. Univ Roma Tor Vergata, Dipartimento Fis, I-00133 Rome, Italy. Lab Astroparticule & Cosmol, F-75231 Paris 05, France. Univ Paris 07, CEA, Observ Paris, CNRS,UMR 7164, F-75221 Paris 05, France. Univ Calif Berkeley, Lawrence Berkeley Lab, Computat Res Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Pasadena, CA 91125 USA. Univ Warsaw Observ, PL-00478 Warsaw, Poland. Univ Helsinki, Dept Phys Sci, FIN-00014 Helsinki, Finland. Helsinki Inst Phys, Helsinki 00014, Finland. Inst Astrophys Paris, F-75014 Paris, France. Max Planck Inst Astrophys, D-85741 Garching, Germany. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. RP Ashdown, MAJ (reprint author), Univ Cambridge, Cavendish Lab, Astrophys Grp, JJ Thomson Ave, Cambridge CB3 0HE, England. EM maja1@mrao.cam.ac.uk RI de Gasperis, Giancarlo/C-8534-2012; Kurki-Suonio, Hannu/B-8502-2016; OI de Gasperis, Giancarlo/0000-0003-2899-2171; Hivon, Eric/0000-0003-1880-2733; Kurki-Suonio, Hannu/0000-0002-4618-3063; WANDELT, Benjamin/0000-0002-5854-8269 NR 27 TC 39 Z9 39 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2007 VL 467 IS 2 BP 761 EP 775 DI 10.1051/0004-6361:20065829 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 167BF UT WOS:000246424900040 ER PT J AU Ormel, CW Cuzzi, JN AF Ormel, C. W. Cuzzi, J. N. TI Closed-form expressions for particle relative velocities induced by turbulence (Research Note) SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE turbulence; dust,extinction; planetary systems : protoplanetary disks ID PROTOPLANETARY DISKS; DUST COAGULATION; SOLAR NEBULA; GRAINS; EVOLUTION; GROWTH; GAS AB In this note we present complete, closed-form expressions for random relative velocities between colliding particles of arbitrary size in nebula turbulence. These results are exact for very small particles ( those with stopping times much shorter than the large eddy overturn time) and are also surprisingly accurate in complete generality ( that is, also apply for particles with stopping times comparable to, or much longer than, the large eddy overturn time). We note that some previous studies may have adopted previous simple expressions, which we find to be in error regarding the size dependence in the large particle regime. C1 Univ Groningen, Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Ormel, CW (reprint author), Univ Groningen, Kapteyn Astron Inst, POB 800, NL-9700 AV Groningen, Netherlands. EM ormel@astro.rug.nl; jcuzzi@mail.arc.nasa.gov NR 14 TC 128 Z9 128 U1 0 U2 5 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2007 VL 466 IS 2 BP 413 EP 420 DI 10.1051/0004-6361:20066899 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 156YW UT WOS:000245686800007 ER PT J AU Kuulkers, E Shaw, SE Paizis, A Chenevez, J Brandt, S Courvoisier, TJL Domingo, A Ebisawa, K Kretschmar, P Markwardt, CB Mowlavi, N Oosterbroek, T Orr, A Risquez, D Sanchez-Fernandez, C Wijnands, R AF Kuulkers, E. Shaw, S. E. Paizis, A. Chenevez, J. Brandt, S. Courvoisier, T. J. -L. Domingo, A. Ebisawa, K. Kretschmar, P. Markwardt, C. B. Mowlavi, N. Oosterbroek, T. Orr, A. Risquez, D. Sanchez-Fernandez, C. Wijnands, R. TI The INTEGRAL Galactic bulge monitoring program: the first 1.5 years SO ASTRONOMY & ASTROPHYSICS LA English DT Review DE accretion, accretion disks; binaries : close; binaries : general; stars : neutron; Galaxy : bulge; X-rays : binaries ID X-RAY BINARIES; ACCRETING PULSAR GX-1+4; LONG-TERM VARIABILITY; CENTER REGION; NEUTRON-STAR; SPECTRAL STATES; SIGMA-TELESCOPE; RXTE OBSERVATIONS; SAX J1747.0-2853; IBIS TELESCOPE AB Aims. The Galactic bulge region is a rich host of variable high-energy point sources. Since 2005, February 17 we are monitoring the source activity in the Galactic bulge region regularly and frequently, i.e., about every three days, with the instruments onboard INTEGRAL. Thanks to the large field of view, the imaging capabilities and the sensitivity at hard X-rays, we are able to present for the first time a detailed homogeneous (hard) X-ray view of a sample of 76 sources in the Galactic bulge region. Methods. We describe the successful monitoring program and show the first results from the start of the monitoring up to 2006, April 21, i.e., for a period of about one and a half year, during three visibility seasons. We focus on the short (hour), medium (month) and long-term (year) variability in the hard X-ray bands, i.e., 20-60 keV and 60-150 keV. When available, we discuss the simultaneous observations in the soft X-ray, 3-10 keV and 10-25 keV, bands. Results. Almost all the sources in the Galactic bulge region we detect in the 20-60 keV and 60-150 keV bands are variable. During the last two and a half weeks of the third visibility season most of the known persistent (hard) X-ray sources in the Galactic Center region were not detected. Of our sample of sources, per visibility season we detect 32/33 sources in the 20-60 keV band and 8/9 sources in the 60-150 keV band above a signal to noise of 7. On average, we find per visibility season one active bright (greater than or similar to 100 mCrab, 20-60 keV) black-hole candidate X-ray transient and three active weaker (less than or similar to 25 mCrab, 20-60 keV) neutron star X-ray transients. Most of the time a clear anti-correlation can be seen between the soft and hard X-ray emission in some of the X-ray bursters. Hard X-ray flares or outbursts in X-ray bursters, which have a duration of the order of weeks are accompanied by soft X- ray drops. On the other hand, hard X-ray drops can be accompanied by soft X-ray flares/outbursts. During the course of our program we found a number of new sources, IGR J17354-3255, IGR 17453-2853, IGR J17454-2703, IGR J17456-2901b, IGR J17536-2339, and IGR J17541-2252. We report here on some of the high-energy properties of these sources. Conclusions. The high-energy light curves of all the sources in the field of view, and the high-energy images of the region, are made available through the WWW, as soon as possible after the observations have been performed, at http://isdc.unige.ch/Science/BULGE/. C1 ISOC, ESA, ESAC, Madrid 28080, Spain. Univ Southampton, Sch Phys & Astron, Southampton S017 1BJ, Hants, England. ISDC, CH-1290 Versoix, Switzerland. INAF, IASF, Sez MIlano, I-20133 Milan, Italy. Danish Natl Space Ctr, DK-2100 Copenhagen, Denmark. Observ Geneva, CH-1290 Sauverny, Switzerland. INTA, Lab Astrofis Espacial & Fis Fundamental, Madrid 28080, Spain. Inst Space & Astronaut Sci, Ctr Planning & Informat Syst, Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Xray Astrophys Lab, Greenbelt, MD 20771 USA. European Space Agcy, ESTEC, Sci Payload & Adv Concepts Off, NL-2200 AG Noordwijk, Netherlands. European Space Agcy, ESTEC, Res & Sci Support Dept, NL-2200 AG Noordwijk, Netherlands. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. RP Kuulkers, E (reprint author), ISOC, ESA, ESAC, Urb Villafranca Castillo,POB 50727, Madrid 28080, Spain. EM Erik.Kuulkers@esa.int RI Chenevez, Jerome/F-5380-2010; Domingo, Albert/L-9071-2014; OI Domingo, Albert/0000-0001-9764-6411; Kretschmar, Peter/0000-0001-9840-2048; Paizis, Adamantia/0000-0001-5067-0377; Bazzano, Angela/0000-0002-2017-4396 NR 170 TC 56 Z9 56 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2007 VL 466 IS 2 BP 595 EP U23 DI 10.1051/0004-6361:20066651 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 156YW UT WOS:000245686800022 ER PT J AU Weissman, PR Lowry, SC Choi, YJ AF Weissman, P. R. Lowry, S. C. Choi, Y.-J. TI Photometric observations of Rosetta target asteroid 2867 Steins SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE minors planets, asteroids ID HAYABUSA; ITOKAWA; 2867-STEINS; MISSION AB Asteroid 2867 Steins is one of two flyby targets of ESA's International Rosetta Mission, launched in March, 2004. We obtained CCD observations of Steins on April 14-16, 2004 at Table Mountain Observatory, California, in order to characterize the asteroid physically, information that is crucial for planning the Steins flyby. This study includes the first detailed analysis of the physical properties of Steins from time-series R-filter data along with V- and I-filter photometric measurements. We found a mean R-filter absolute magnitude of 12.60 +/- 0.02 (for G = 0.15), corresponding to a mean radius of 3.57 +/- 0.03 km assuming an S-type reflectance of 0.20, or 2.24 +/- 0.02 km assuming an E-type reflectance of 0.40 (and G = 0.40). The observed brightness range of 0.29 +/- 0.04 mag suggests a lower limit on the axial ratio, a/b, of 1.30. We determined a synodic rotation period of 6.048 +/- 0.007 h, assuming a double-peaked lightcurve. We fitted the available R-filter photometry over the phase angle range of 11.08 - 17.07 degrees and found best-fit phase function parameters of G = 0.46(-0.20)(+0.32), and H = 12.92(-0.17)(+0.22). Derived colour indices for the asteroid are (V - R) = 0.58 +/- 0.03, and (R - I) = 0.44 +/- 0.03. These values are consistent with, though slightly redder than Hicks et al. (IAUC 8315). Barucci et al. (2005) identified Steins as an E-type based on visual and near-infrared spectra, but if that is correct, then it is an unusually red E-type asteroid. C1 CALTECH, Jet Prop Lab, Div Sci, Pasadena, CA 91109 USA. Queens Univ Belfast, Sch Math & Phys, Belfast BT7 1NN, Antrim, North Ireland. RP Weissman, PR (reprint author), CALTECH, Jet Prop Lab, Div Sci, 4800 Oak Grove Dr,MS 183-301, Pasadena, CA 91109 USA. EM paul.r.weissman@jpl.nasa.gov; s.c.lowry@qub.ac.uk; young-jun.choi@jpl.nasa.gov NR 22 TC 12 Z9 12 U1 0 U2 2 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2007 VL 466 IS 2 BP 737 EP 742 DI 10.1051/0004-6361:20066409 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 156YW UT WOS:000245686800038 ER PT J AU Cleary, K Lawrence, CR Marshall, JA Hao, L Meier, D AF Cleary, K. Lawrence, C. R. Marshall, J. A. Hao, L. Meier, D. TI Spitzer observations of 3c quasars and radio galaxies: Mid-infrared properties of powerful radio sources SO ASTROPHYSICAL JOURNAL LA English DT Article ID ACTIVE GALACTIC NUCLEI; COMPACT STEEP-SPECTRUM; FAR-INFRARED EMISSION; UNIFIED SCHEMES; SPACE-TELESCOPE; SUPERLUMINAL MOTION; SILICATE EMISSION; IRS SPECTROSCOPY; LINE DIAGNOSTICS; THICK TORI AB We have measured mid-infrared radiation from an orientation-unbiased sample of 3CRR galaxies and quasars at redshifts 0.4 <= z <= 1.2 with the IRS and MIPS instruments on Spitzer. Powerful emission (L-24 mu m > 10(22.4) W Hz(-1) sr(-1)) was detected from all but one of the sources. We fit the Spitzer data and other measurements from the literature with synchrotron and dust components. The IRS data provide powerful constraints on the fits. At 15 mu m, quasars are typically 4 times brighter than radio galaxies with the same isotropic radio power. Based on our fits, half of this difference can be attributed to the presence of nonthermal emission in the quasars but not the radio galaxies. The other half is consistent with dust absorption in the radio galaxies but not the quasars. Fitted optical depths are anticorrelated with core dominance, from which we infer an equatorial distribution of dust around the central engine. The median optical depth at 9.7 mu m for objects with core dominance factor R > 10(-2) is approximate to 0.4; for objects with R <= 10(-2), it is approximate to 1.1. We have thus addressed a long-standing question in the unification of FR II quasars and galaxies: quasars are more luminous in the mid-infrared than galaxies because of a combination of Doppler-boosted synchrotron emission in quasars and extinction in galaxies, both orientation-dependent effects. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. RP Cleary, K (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM kieran.a.cleary@jpl.nasa.gov NR 54 TC 76 Z9 76 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP 117 EP 145 DI 10.1086/511969 PN 1 PG 29 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162SB UT WOS:000246108700008 ER PT J AU Koester, BP Mckay, TA Annis, J Wechsler, RH Evrard, AE Rozo, E Bleem, L Sheldon, ES Johnston, D AF Koester, Benjamin P. McKay, Timothy A. Annis, James Wechsler, Risa H. Evrard, August E. Rozo, Eduardo Bleem, Lindsey Sheldon, Erin S. Johnston, David TI MaxBCG: A red-sequence galaxy cluster finder SO ASTROPHYSICAL JOURNAL LA English DT Review ID DIGITAL SKY SURVEY; X-RAY-CLUSTERS; MORPHOLOGY-DENSITY RELATION; COLOR-MAGNITUDE RELATION; CAMPANAS REDSHIFT SURVEY; TO-LIGHT RATIO; LUMINOSITY FUNCTION; COSMOLOGICAL PARAMETERS; VELOCITY DISPERSIONS; DISTANT CLUSTERS AB Measurements of galaxy cluster abundances, clustering properties, and mass-to-light ratios in current and future surveys can provide important cosmological constraints. Digital wide-field imaging surveys, the recently demonstrated fidelity of red-sequence cluster detection techniques, and a new generation of realistic mock galaxy surveys provide the means for construction of large, cosmologically interesting cluster samples, whose selection and properties can be understood in unprecedented depth. Here we present the details of the "maxBCG'' algorithm, a cluster detection technique tailored to multiband CCD imaging data. MaxBCG primarily relies on an observational cornerstone of massive galaxy clusters: they are marked by an overdensity of bright, uniformly red galaxies. This detection scheme also exploits classical brightest cluster galaxies (BCGs), which are often found at the centers of these same massive clusters. We study the algorithm through its performance on large, realistic, mock galaxy catalogs, which reveal that it is over 90% pure for clusters at 0.1 < z < 0.3 with 10 or more red galaxies, and over 90% complete for halos at 0.1 < z < 0.3 with masses above 2 x 10(14) h(-1) M-circle dot. MaxBCG is able to approximately recover the underlying halo abundance function and assign cluster richnesses strongly coupled to the underlying halo properties. The same tests indicate that maxBCG rarely fragments halos, occasionally overmerges line-of-sight neighboring (similar or equal to 10 h(-1) Mpc) halos, and overestimates the intrinsic halo red-sequence galaxy population by no more than 20%. The study concludes with a discussion of considerations for cosmological measurements with such catalogs, including modeling the selection function, the role of photometric errors, the possible cosmological dependence of richness measurements, and fair cluster selection across broad redshift ranges employing multiple bandpasses. C1 Univ Michigan, Dept Phys, Ann Arbor, MI 48104 USA. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Chicago, Kavli Inst Cosmol Phys, Chicago, IL 60637 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Chicago, Dept Phys, Chicago, IL 60637 USA. NYU, Ctr Cosmol & Particle Phys, New York, NY 10003 USA. NYU, Dept Phys, New York, NY 10003 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Koester, BP (reprint author), Univ Michigan, Dept Phys, Ann Arbor, MI 48104 USA. EM bkoester@umich.edu; tamckay@umich.edu RI McKay, Timothy/C-1501-2009; OI McKay, Timothy/0000-0001-9036-6150; Evrard, August/0000-0002-4876-956X NR 115 TC 156 Z9 156 U1 0 U2 8 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP 221 EP 238 DI 10.1086/512092 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162SB UT WOS:000246108700016 ER PT J AU Koester, BP Mckay, TA Annis, J Wechsler, RH Evrard, A Bleem, L Becker, M Johnston, D Sheldon, E Nichol, R Miller, C Scranton, R Bahcall, N Barentine, J Brewington, H Brinkmann, J Harvanek, M Kleinman, S Krzesinski, J Long, D Nitta, A Schneider, DP Sneddin, S Voges, W York, D AF Koester, B. P. Mckay, T. A. Annis, J. Wechsler, R. H. Evrard, A. Bleem, L. Becker, M. Johnston, D. Sheldon, E. Nichol, R. Miller, C. Scranton, R. Bahcall, N. Barentine, J. Brewington, H. Brinkmann, J. Harvanek, M. Kleinman, S. Krzesinski, J. Long, D. Nitta, A. Schneider, D. P. Sneddin, S. Voges, W. York, D. TI A MaxBCG catalog of 13,823 galaxy clusters from the sloan digital sky survey SO ASTROPHYSICAL JOURNAL LA English DT Review ID SPECTROSCOPIC TARGET SELECTION; WEAK-LENSING MEASUREMENTS; SDSS COMMISSIONING DATA; BRIGHT SHARC SURVEY; X-RAY; RICH CLUSTERS; LUMINOSITY FUNCTION; REDSHIFT SURVEY; ABELL CLUSTERS; RADIAL-DISTRIBUTION AB We present a catalog of galaxy clusters selected using the maxBCG red-sequence method from Sloan Digital Sky Survey photometric data. This catalog includes 13,823 clusters with velocity dispersions greater than approximate to 400 km s(-1) and is the largest galaxy cluster catalog assembled to date. They are selected in an approximately volume-limited way from a 0.5 Gpc(3) region covering 7500 deg(2) of sky between redshifts 0.1 and 0.3. Each cluster contains between 10 and 190 E/S0 ridgeline galaxies brighter than 0.4L(*) within a scaled radius R-200. The tight relation between ridgeline color and redshift provides an accurate photometric redshift estimate for every cluster. Photometric redshift errors are shown by comparison to spectroscopic redshifts to be small (Delta(z) similar or equal to 0.01), essentially independent of redshift, and well determined throughout the redshift range. Runs of maxBCG on realistic mock catalogs suggest that the sample is more than 90% pure and more than 85% complete for clusters with masses >= 1 x 10(14) M-circle dot. Spectroscopic measurements of cluster members are used to examine line-of-sight projection as a contaminant in the identification of brightest cluster galaxies and cluster member galaxies. Spectroscopic data are also used to demonstrate the correlation between optical richness and velocity dispersion. Comparison to the combined NORAS and REFLEX X-ray-selected cluster catalogs shows that X-ray-luminous clusters are found among the optically richer maxBCG clusters. This paper is the first in a series that will consider the properties of these clusters, their galaxy populations, and their implications for cosmology. C1 Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. Univ Michigan, Michigan Ctr Theoret Phys, Ann Arbor, MI 48109 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Chicago, Dept Astron & Astrophys, Kavli Inst Cosmol Phys, Chicago, IL 60637 USA. Univ Chicago, Dept Phys, Chicago, IL 60637 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. NYU, Ctr Cosmol & Particle Phys, New York, NY USA. Univ Portsmouth, Inst Cosmol & Gravit, Portsmouth, Hants, England. Natl Opt Astron Observ, Cerro Tololo Inter Amer Observ, La Serena, Chile. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. Apache Point Observ, Sunspot, NM USA. Cracow Pedag Univ, Mt Suhora Observ, Krakow, Poland. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. RP Koester, BP (reprint author), Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. EM bkoester@umich.edu; tamckay@umich.edu RI McKay, Timothy/C-1501-2009; OI McKay, Timothy/0000-0001-9036-6150; Evrard, August/0000-0002-4876-956X; Becker, Matthew/0000-0001-7774-2246 NR 118 TC 368 Z9 368 U1 1 U2 10 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP 239 EP 255 DI 10.1086/509599 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162SB UT WOS:000246108700017 ER PT J AU Willacy, K AF Willacy, K. TI The chemistry of multiply deuterated molecules in protoplanetary disks. I. The outer disk SO ASTROPHYSICAL JOURNAL LA English DT Article ID DENSE INTERSTELLAR CLOUDS; T-TAURI STARS; YOUNG STELLAR OBJECTS; O1 HALE-BOPP; DEUTERIUM FRACTIONATION; DM-TAURI; HYDROGEN FORMATION; ACCRETION DISKS; ICE SURFACES; MONTE-CARLO AB We present new models of the deuterium chemistry in protoplanetary disks, including, for the first time, multiply deuterated species. We use these models to explore whether observations in combination with models can give us clues as to which desorption processes occur in disks. We find, in common with other authors, that photodesorption can allow strongly bound molecules such as HDO to exist in the gas phase in a layer above the midplane. Models including this process give the best agreement with the observations. In the midplane, cosmic-ray heating can desorb weakly bound molecules such as CO and N-2. We find the observations suggest that N2 is gaseous in this region, but that CO must be retained on the grains to account for the observed DCO+/HCO+. This could be achieved by CO having a higher binding energy than N2 ( as may be the case when these molecules are accreted onto water ice) or by a smaller cosmic-ray desorption rate for CO than assumed here, as suggested by recent theoretical work. For gaseous molecules the calculated deuteration can be greatly changed by chemical processing in the disk from the input molecular cloud values. On the grains singly deuterated species tend to retain the D/H ratio set in the molecular cloud, whereas multiply deuterated species are more affected by the disk chemistry. Consequently, the D/H ratios observed in comets may be partly set in the parent cloud and partly in the disk, depending on the molecule. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Willacy, K (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM karen.willacy@jpl.nasa.gov NR 88 TC 55 Z9 55 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP 441 EP 460 DI 10.1086/512796 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162SB UT WOS:000246108700035 ER PT J AU Titarchuk, L Shaposhnikov, N Arefiev, V AF Titarchuk, Lev Shaposhnikov, Nikolai Arefiev, Vadim TI Power spectra of black holes and neutron stars as a probe of hydrodynamic structure of the source: Diffusion theory and its application to Cygnus X-1 and Cygnus X-2 X-ray observations SO ASTROPHYSICAL JOURNAL LA English DT Article ID OSCILLATION FREQUENCY CORRELATION; ACCRETION DISCS; INTRINSIC SIGNATURE; BINARIES; VARIABILITY; COMPTONIZATION; CANDIDATES; RADIATION; INDEX; DISKS AB We present a model of Fourier power density spectrum (PDS) formation in accretion-powered X-ray binary systems derived from diffusion theory. Timing properties of X-ray emission are considered a result of diffusive propagation of the driving perturbations in a bounded medium. We prove that the integrated power P-x of the resulting PDS is only a small fraction of the integrated power P-dr of the driving oscillations, which is distributed over the disk. Furthermore, we demonstrate that Px is inversely proportional to the characteristic frequency of the driving oscillations nu(dr), which likely scales with the frequency of the local gravity waves in the disk (Keplerian frequency). Because nu(dr) increases toward soft states, we conclude that P-x declines toward soft states. This dependence P-x proportional to nu(-1)(dr) explains the well-known observational phenomenon that the X-ray variability power decreases when the source evolves to softer states. The resulting PDS continuum is a sum of a low-frequency (LF) component, which presumably originates in an extended accretion disk, and a high-frequency (HF) component, which originates in the innermost part of the source (Compton cloud or corona). The LF PDS component has a power-law shape with an index of 1.0-1.5 at higher frequencies ("red'' noise) and a flat spectrum below a characteristic (break) frequency ("white'' noise). This white-red noise (WRN) continuum spectrum holds information about the bounded extended medium, the diffusion timescale, and the dependence law of viscosity versus radius. We apply our model of the PDS to RXTE and EXOSAT timing data from Cygnus X-1 and Cygnus X-2, which describes adequately the spectral transitions in these sources. The presented PDSs are shown in frequency range from 10 (-8) to 102 Hz, 10 orders of magnitude. C1 George Mason Univ, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. USN, Res Lab, Washington, DC 20375 USA. Univ Ferrara, Dipartmento Fis, I-44100 Ferrara, Italy. NASA, Goddard Space Flight Ctr, Astrophys Sci Div, Greenbelt, MD 20771 USA. Univ Space Res Assoc, CRESST, Columbia, MD 21044 USA. Russian Acad Sci, Space Res Inst, IKI, Moscow 117997, Russia. RP Titarchuk, L (reprint author), George Mason Univ, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. EM ltitarchuk@ssd5.nrl.navy.mil; nikolai@milkyway.gsfc.nasa.gov; gita@hea.iki.rssi.ru NR 38 TC 41 Z9 41 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP 556 EP 579 DI 10.1086/512027 PN 1 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162SB UT WOS:000246108700046 ER PT J AU Strohmayer, TE Mushotzky, RF Winter, L Soria, R Uttley, P Cropper, M AF Strohmayer, Tod E. Mushotzky, Richard F. Winter, Lisa Soria, Roberto Uttley, Phil Cropper, Mark TI Quasi-periodic variability in NGC 5408 X-1 SO ASTROPHYSICAL JOURNAL LA English DT Article ID X-RAY SOURCE; MASS BLACK-HOLES; XMM-NEWTON OBSERVATIONS; MICROQUASAR GRO J1655-40; XTE J1550-564; ACCRETION DISKS; NEARBY GALAXIES; M82 X-1; OSCILLATIONS; FREQUENCY AB We report the discovery with XMM-Newton of quasi-periodic variability in the 0.2-10 keV X-ray flux from the ULX NGC 5408 X-1. The average power spectrum of all EPIC-pn data reveals a strong 20 mHz QPO with an average amplitude (rms) of 9% and a coherence Q equivalent to nu(0)/sigma approximate to 6. In a 33 ks time interval when the 20 mHz QPO is strongest we also find evidence for a second QPO peak at 15 mHz, the first indication of a close pair of QPOs in a ULX source. The frequency ratio of this QPO pair is inconsistent with 3: 2 at the 3 sigma level but is consistent with a 4: 3 ratio. A power-law noise component with slope near 1.5 is also present below 0.1 Hz with evidence for a break to a flatter slope at about 3 mHz. The source shows substantial broadband variability, with a total amplitude (rms) of about 30% in the 0.1-100 mHz frequency band. The power spectrum of hard X-ray photons (> 2 keV) shows a "`classic'' flat-topped continuum breaking to a power law with index 1.5-2. Both the break and 20 mHz QPO are detected in the hard band, and the 20 mHz QPO is essentially at the break. The QPO is both strong and narrow in this band, having an amplitude (rms) of 15%, and Q approximate to 25. Both the timing and spectral properties of NGC 5408 X-1 are strikingly reminiscent of Galactic black holes at high inferred accretion rates, but with its characteristic frequencies (QPO and break frequencies) scaled down by a factor of 10-100. We discuss the implications of these findings for the object's mass. C1 NASA, Goddard Space Flight Ctr, Astrophys Sci Div, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. RP Strohmayer, TE (reprint author), NASA, Goddard Space Flight Ctr, Astrophys Sci Div, Greenbelt, MD 20771 USA. EM stroh@milkyway.gsfc.nasa.gov; richard@milkyway.gsfc.nasa.gov; lwinter@astro.umd.edu; rsoria@head.cfa.harvard.edu; msc@mssl.ucl.ac.uk RI Cropper, Mark/C-1574-2008; OI Winter, Lisa/0000-0002-3983-020X NR 54 TC 92 Z9 93 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP 580 EP 586 DI 10.1086/512723 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162SB UT WOS:000246108700047 ER PT J AU Krauss, MI Schulz, NS Chakrabarty, D Juett, AM Cottam, J AF Krauss, Miriam I. Schulz, Norbert S. Chakrabarty, Deepto Juett, Adrienne M. Cottam, Jean TI High-resolution X-ray spectroscopy of the ultracompact LMXB pulsar 4u 1626-67 SO ASTROPHYSICAL JOURNAL LA English DT Article ID RICH DEGENERATE DONORS; BINARY 4U 1626-67; HELIUM-LIKE IONS; INTERSTELLAR-MEDIUM; ABSORPTION; NEON; TRANSIENTS; DISCOVERY; SPECTRUM; SYSTEMS AB We report results from four recent observations of the ultracompact LMXB pulsar 4U 1626-67. These observations obtained high-resolution X-ray spectra with Chandra HETGS and XMM RGS, allowing us to study in detail the prominent Ne and O emission-line complexes. The observations were spaced over a period of 3 yr, enabling us to monitor the line regions as well as the overall spectral and timing properties. The structure of the emission lines and the helium-like Ne IX and O VII triplets support the hypothesis that they are formed in the high-density environment of an accretion disk. We do not find any significant variability in the line widths or ratios, though we note that the equivalent widths decrease. Using the most recent calibration products, we are able to place constraints on the strengths of the Ne K, Fe L, and O K photoelectric absorption edges. In contrast to our earlier analysis, the data do not require an overabundance of Ne or O in the system relative to the expected ISM values. We find that the pulsar is still spinning down but note that the pulse profile has changed significantly from what was found prior to the torque reversal in 1990, suggesting a change in the geometry of the accretion column. The flux of 4U 1626-67 continues to decrease, following the trend of the last approximate to 30 yr over which it has been observed. Taking into consideration current theory on disk stability, we expect that 4U 1626-67 will enter a period of quiescence in 2-15 yr. C1 MIT, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. RP Krauss, MI (reprint author), MIT, Kavli Inst Astrophys & Space Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA. EM miriam@space.mit.edu; nss@space.mit.edu; deepto@space.mit.edu; ajuett@virginia.edu; jcottam@milkyway.gsfc.nasa.gov NR 38 TC 19 Z9 19 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP 605 EP 614 DI 10.1086/513592 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162SB UT WOS:000246108700050 ER PT J AU Nichols, JS DePasquale, J Kellogg, E Anderson, CS Sokoloski, J AF Nichols, J. S. DePasquale, J. Kellogg, E. Anderson, C. S. Sokoloski, J. TI Discovery of rapid hard X-ray variability and new jet activity in the symbiotic binary R aquarii SO ASTROPHYSICAL JOURNAL LA English DT Article ID CH-CYGNI; CATACLYSMIC VARIABLES; WHITE-DWARF; EX-HYDRAE; INTERMEDIATE POLAR; ASCA OBSERVATIONS; RADIO JET; ULTRAVIOLET; CAMELOPARDALIS; EMISSION AB Two Chandra observations of the R Aqr symbiotic binary system taken 3.3 yr apart show dramatic changes in the X-ray morphology and spectral characteristics in the inner 500 AU of this system. The morphology of the soft X-ray emission has evolved from a nearly circular region centered on the binary system to an hourglass shape that indicates the formation of a new southwest jet. Synchrotron radiation from the new jet in contemporaneous VLA radio spectra implies the physical conditions in the early stages of jet development are different from those in the more extended outer thermal jets known to exist for decades in this system. The central binary source has two X-ray spectral components in each of the two epochs, a soft component and a highly absorbed hard component characterized by T similar to 10(8) K if fit with a thermal plasma model. The spectrum hardened considerably between 2000.7 and 2004.0, primarily due to increased flux above 5 keV, suggesting a change in the accretion activity of the white dwarf on a timescale of a few years or less. Point-source Fe K emission is detected at the position of the central binary system in both observations. While the earlier observation shows evidence of only a single emission peak near Fe K alpha at 6.4 keV, the later observation shows a more complex emission structure between 6 and 7 keV. Finally, we have discovered a modulation in the hard X-ray flux with a period of 1734 s at a 95% confidence level in the 2004 observation only. The modulation potentially arises from standing shocks in an accretion column, and we have explored the possibility that the white dwarf in R Aqr is analogous to the magnetic white dwarfs in Intermediate Polars. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Nichols, JS (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM jnichols@cfa.harvard.edu NR 52 TC 20 Z9 20 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP 651 EP 661 DI 10.1086/512138 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162SB UT WOS:000246108700053 ER PT J AU Nielsen, KE Corcoran, MF Gull, TR Hillier, DJ Hamaguchi, K Ivarsson, S Lindler, DJ AF Nielsen, K. E. Corcoran, M. F. Gull, T. R. Hillier, D. J. Hamaguchi, K. Ivarsson, S. Lindler, D. J. TI eta carinae across the 2003.5 minimum: Spectroscopic evidence for massive binary interactions SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : spectroscopic; stars : individual (eta Carinae); stars : winds, outflows ID LONG-PERIOD BINARY; X-RAY; COLLIDING-WINDS; SYSTEM; EVENT; VARIABILITY; PERIASTRON; EMISSION; CAR; INTERFEROMETRY AB We have analyzed high spatial, moderate spectral resolution observations of eta Carinae (eta Car) obtained with the STIS from 1998.0 to 2004.3. The data were obtained at discrete times covering an entire 2024 day spectroscopic cycle, with focus on the X-ray/ionization low state that began in 2003 June. The spectra show prominent P Cygni lines in H I, Fe II, and He I, which are complicated by blends and contamination by nebular emission and absorption. All lines show phase- and species-dependent variations in emission and absorption. For most of the cycle the He I emission is blue-shifted relative to the HI and Fe II PCygni emission lines, which are centered at approximately system velocity. The blue-shifted He I absorption components vary in intensity and velocity throughout the 2024 day period. We construct radial velocity curves for the absorption component of the He I and H I lines. The He I absorption shows significant radial velocity variations throughout the cycle, with a rapid change of over 200 km s(-1) near the 2003.5 event. The H I velocity curve is similar to that of the He I absorption, although offset in phase and reduced in amplitude. We interpret the complex line profile variations in He I, H I, and Fe II to be a consequence of the dynamic interaction of the dense wind of eta Car A with the less dense, faster wind plus the radiation field of a hot companion star, eta Car B. We use the variations seen in He I and the other P Cygni lines to constrain the geometry of the orbit and the character of eta Car B. C1 Catholic Univ Amer, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, CRESST, Astrophys Sci Div, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. Sigma Space Corp, Lanham, MD 20706 USA. RP Nielsen, KE (reprint author), Catholic Univ Amer, Washington, DC 20064 USA. EM nielsen@milkyway.gsfc.nasa.gov RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 52 TC 56 Z9 56 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP 669 EP 686 DI 10.1086/513006 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162SB UT WOS:000246108700055 ER PT J AU Quintana, EV Adams, FC Lissauer, JJ Chambers, JE AF Quintana, Elisa V. Adams, Fred C. Lissauer, Jack J. Chambers, John E. TI Terrestrial planet formation around individual stars within binary star systems SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : general; planets and satellites : formation ID ALPHA-CENTAURI SYSTEM; STELLAR MULTIPLICITY; RELATIVE VELOCITIES; CIRCUMBINARY DISCS; STABILITY; PLANETESIMALS; EXOPLANETS; ACCRETION; ORBITS AB We calculate herein the late stages of terrestrial planet accumulation around a solar-type star that has a binary companion with semimajor axis larger than the terrestrial planet region. We perform more than 100 simulations to survey binary parameter space and to account for sensitive dependence on initial conditions in these dynamical systems. As expected, sufficiently wide binaries leave the planet formation process largely unaffected. As a rough approximation, binary stars with periastron q(B) > 10 AU have a minimal effect on terrestrial planet formation within similar to 2 AU of the primary, whereas binary stars with q(B) less than or similar to 5AU restrict terrestrial planet formation to within similar to 1 AU of the primary star. Given the observed distribution of binary orbital elements for solar-type primaries, we estimate that about 40%-50% of the binary population is wide enough to allow terrestrial planet formation to take place unimpeded. The large number of simulations allows us to determine the distribution of results-the distribution of plausible terrestrial planet systems-for effectively equivalent starting conditions. We present (rough) distributions for the number of planets, their masses, and their orbital elements. C1 NASA, Ames Res Ctr, Space Sci & Astrobiol Div 245 3, Moffett Field, CA 94035 USA. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. RP Quintana, EV (reprint author), NASA, Ames Res Ctr, Space Sci & Astrobiol Div 245 3, Moffett Field, CA 94035 USA. EM equintana@mail.arc.nasa.gov NR 34 TC 71 Z9 71 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP 807 EP 822 DI 10.1086/512542 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162SB UT WOS:000246108700068 ER PT J AU Mandell, AM Raymond, SN Sigurdsson, S AF Mandell, Avi M. Raymond, Sean N. Sigurdsson, Steinn TI Formation of earth-like planets during and after giant planet migration SO ASTROPHYSICAL JOURNAL LA English DT Review DE astrobiology; methods : n-body simulations; planetary systems : formation ID PRIMORDIAL SOLAR NEBULA; GALACTIC HABITABLE ZONE; CARBON-DIOXIDE CLOUDS; T-TAURI DISKS; TERRESTRIAL PLANETS; EXTRASOLAR PLANETS; PROTOPLANETARY DISKS; OLIGARCHIC GROWTH; PREDICTING PLANETS; ORBITAL MIGRATION AB Close-in giant planets are thought to have formed in the cold outer regions of planetary systems and migrated inward, passing through the orbital parameter space occupied by the terrestrial planets in our own solar system. We present dynamical simulations of the effects of a migrating giant planet on a disk of protoplanetary material and the subsequent evolution of the planetary system. We numerically investigate the dynamics of postmigration planetary systems over 200 million years using models with a single migrating giant planet, one migrating and one nonmigrating giant planet, and excluding the effects of a gas disk. Material that is shepherded in front of the migrating giant planet by moving mean motion resonances accretes into "hot Earths,'' but survival of these bodies is strongly dependent on dynamical damping. Furthermore, a significant amount of material scattered outward by the giant planet survives in highly excited orbits; the orbits of these scattered bodies are then damped by gas drag and dynamical friction over the remaining accretion time. In all simulations Earth-mass planets accrete on approximately 100 Myr timescales, often with orbits in the habitable zone. These planets range in mass and water content, with both quantities increasing with the presence of a gas disk and decreasing with the presence of an outer giant planet. We use scaling arguments and previous results to derive a simple recipe that constrains which giant planet systems are able to form and harbor Earth-like planets in the habitable zone, demonstrating that roughly one-third of the known planetary systems are potentially habitable. C1 Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16803 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mandell, AM (reprint author), Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16803 USA. EM mandell@astro.psu.edu RI Mandell, Avi/F-9361-2012; OI Sigurdsson, Steinn/0000-0002-8187-1144 NR 127 TC 86 Z9 87 U1 2 U2 12 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP 823 EP 844 DI 10.1086/512759 PN 1 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162SB UT WOS:000246108700069 ER PT J AU Kasper, JC Stevens, ML Lazarus, AJ Steinberg, JT Ogilvie, KW AF Kasper, Justin C. Stevens, Michael L. Lazarus, Alan J. Steinberg, John T. Ogilvie, Keith. W. TI Solar wind helium abundance as a function of speed and heliographic latitude: Variation through a solar cycle SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; interplanetary medium; plasmas; sun : abundances; sun : corona; sun : fundamental parameters ID DIFFERENTIAL FLOW; MAGNETIC-FIELDS; MINOR IONS; ACCELERATION; PARTICLES; PROTONS; 0.3-AU; CORONA; 1-AU AB We present a study of the variation of the relative abundance of helium to hydrogen in the solar wind as a function of solar wind speed and heliographic latitude over the previous solar cycle. The average values of A(He), the ratio of helium to hydrogen number densities, are calculated in 25 speed intervals over (similar to 27 day) Carrington rotations using Faraday cup observations from the Wind spacecraft between 1995 and 2005. We find that for solar wind speeds between 350 and 415 km s(-1), AHe varies with a clear 6 month periodicity, with a minimum value at the heliographic equatorial plane and a typical gradient of 1% per degree in latitude. Once the gradient is subtracted, we find that AHe is a remarkably linear function of solar wind speed. We identify the implied speed at which A(He) is zero as 259 +/- 12 km s(-1) and note that this speed corresponds to the minimum solar wind speed observed at 1 AU. The vanishing speed may be related to previous theoretical work in which enhancements of coronal helium lead to stagnation of the escaping proton flux. During solar maximum the A(He) dependences on speed and latitude disappear, and we interpret this as evidence of two source regions for slow solar wind in the ecliptic plane, one being the solar minimum streamer belt and the other likely being active regions. C1 MIT, Kavili Inst Astrophys & Space Res, Cambridge, MA 02139 USA. Los Alamos Natl Lab, Los Alamos, NM USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kasper, JC (reprint author), MIT, Kavili Inst Astrophys & Space Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA. EM jck@mit.edu RI Kasper, Justin/D-1152-2010 OI Kasper, Justin/0000-0002-7077-930X NR 39 TC 51 Z9 51 U1 1 U2 11 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP 901 EP 910 DI 10.1086/510842 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162SB UT WOS:000246108700077 ER PT J AU Elsila, JE Dworkin, JP Bernstein, MP Martin, MP Sandford, SA AF Elsila, Jamie E. Dworkin, Jason P. Bernstein, Max P. Martin, Mildred P. Sandford, Scott A. TI Mechanisms of amino acid formation in interstellar ice analogs SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrobiology; astrochemistry; ISM : molecules; molecular processes ID TERT-BUTYLDIMETHYLSILYL DERIVATIVES; GAS-LIQUID-CHROMATOGRAPHY; MURCHISON METEORITE; DEUTERIUM ENRICHMENT; MASS-SPECTROMETRY; ISOTOPIC ANALYSES; RADIATION-FIELD; DENSE CLOUDS; GLYCINE; HYDROCARBONS AB Amino acids have been identified in carbonaceous chondrites, but their origin is yet unknown. Previous work has shown that a variety of amino acids can be formed via ultraviolet photolysis of interstellar ice analogs. Two possible mechanisms of formation of these amino acids have been proposed: a Strecker-type synthesis or a radical-radical mechanism. In this work, we have used isotopic labeling techniques to test the predictions made by each of these proposed mechanisms for the formation of the amino acids glycine and serine. We observe that amino acid formation occurs via multiple pathways, with potentially different mechanisms for glycine and serine. The major reaction paths do not match either of the two predicted mechanisms, although a modified radical-radical mechanism may account for our observations. The observation of multiple routes suggests that the formation of amino acids in interstellar ice analogs is not narrowly dependent on ice composition, but may occur under a variety of conditions that influence product distributions. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Mountain View, CA 94043 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Catholic Univ Amer, Washington, DC 20064 USA. RP Elsila, JE (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM jelsila@mail.arc.nasa.gov RI Elsila, Jamie/C-9952-2012; Meinert, Cornelia/A-9293-2010; Dworkin, Jason/C-9417-2012 OI Meinert, Cornelia/0000-0002-7256-2112; Dworkin, Jason/0000-0002-3961-8997 NR 52 TC 92 Z9 93 U1 2 U2 46 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP 911 EP 918 DI 10.1086/513141 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162SB UT WOS:000246108700078 ER PT J AU Conselice, CJ Newman, JA Georgakakis, A Almaini, O Coil, AL Cooper, MC Eisenhardt, P Foucaud, S Koekemoer, A Lotz, J Noeske, K Weiner, B Willmer, CNA AF Conselice, C. J. Newman, J. A. Georgakakis, A. Almaini, O. Coil, A. L. Cooper, M. C. Eisenhardt, P. Foucaud, S. Koekemoer, A. Lotz, J. Noeske, K. Weiner, B. Willmer, C. N. A. TI AEGIS: The diversity of bright near-IR-selected distant red galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : formation; galaxies : high-redshift; infrared : galaxies ID HIGH-REDSHIFT GALAXIES; MASSIVE GALAXIES; FIELD GALAXIES; MORPHOLOGY; HISTORIES; POPULATION; EVOLUTION; DENSITY AB We use deep and wide near-infrared (NIR) imaging from the Palomar telescope combined with DEEP2 spectroscopy and HST and Chandra imaging to investigate the nature of galaxies that are red in NIR colors. We locate these "distant red galaxies" (DRGs) through the color cut (J - K)(Vega) > 2.5 over 0.7 deg(2), where we find 1010 DRG candidates down to K-s = 20.5. We combine 95 high-quality spectroscopic redshifts with photometric redshifts from BRIJK photometry to determine the redshift and stellar mass distributions for these systems, and the morphological/structural and X-ray properties for 107 DRGs in the Extended Groth Strip. We find that many bright (J - K)(Vega) > 2.3 galaxies with K-s < 20.5 are at redshifts z <2, with 64% in the range 1 < z < 2. The stellar mass distributions for these galaxies are broad, ranging from 10(9) to 10(12) M-circle dot, but with most z > 2 systems being massive with M-* > 10(11) M-circle dot. HST imaging shows that the structural properties and morphologies of DRGs are also diverse, with the majority elliptical/compact (57%) and the remainder edge-on spiral (7%) and peculiar (29%). The DRGs at z < 1.4 with high-quality spectroscopic redshifts are generally compact, with small half-light radii, and span a range in rest-frame optical properties. The spectral energy distribution for the DRGs at z < 1.4 differs from higher redshift DRGs: they are bluer by 1 mag in observed (I - J) color. A pure IR color selection of high-redshift populations is not sufficient to identify unique populations, and other colors or spectroscopic redshifts are needed to produce homogeneous samples. C1 Univ Nottingham, Sch Phys & Astron, Nottingham NG7 2RD, England. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ London Imperial Coll Sci & Technol, London SW7 2BZ, England. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Calif Santa Cruz, Lick Observ, UCO, Santa Cruz, CA 95064 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. RP Conselice, CJ (reprint author), Univ Nottingham, Sch Phys & Astron, Nottingham NG7 2RD, England. RI Conselice, Christopher/B-4348-2013; Georgakakis, Antonis/K-4457-2013; OI Conselice, Christopher/0000-0003-1949-7638; Weiner, Benjamin/0000-0001-6065-7483; Georgakakis, Antonis/0000-0002-3514-2442; Koekemoer, Anton/0000-0002-6610-2048 NR 26 TC 27 Z9 27 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP L55 EP L58 DI 10.1086/517921 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162TP UT WOS:000246112700014 ER PT J AU Davis, M Guhathakurta, P Konidaris, NP Newman, JA Ashby, MLN Biggs, AD Barmby, P Bundy, K Chapman, SC Coil, AL Conselice, CJ Cooper, MC Croton, DJ Eisenhardt, PRM Ellis, RS Faber, SM Fang, T Fazio, GG Georgakakis, A Gerke, BF Goss, WM Gwyn, S Harker, J Hopkins, AM Huang, JS Ivison, RJ Kassin, SA Kirby, EN Koekemoer, AM Koo, DC Laird, ES Le Floc'h, E Lin, L Lotz, JM Marshall, PJ Martin, DC Metevier, AJ Moustakas, LA Nandra, K Noeske, KG Papovich, C Phillips, AC Rich, RM Rieke, GH Rigopoulou, D Salim, S Schiminovich, D Simard, L Smail, I Small, TA Weiner, BJ Willmer, CNA Willner, SP Wilson, G Wright, EL Yan, R AF Davis, M. Guhathakurta, P. Konidaris, N. P. Newman, J. A. Ashby, M. L. N. Biggs, A. D. Barmby, P. Bundy, K. Chapman, S. C. Coil, A. L. Conselice, C. J. Cooper, M. C. Croton, D. J. Eisenhardt, P. R. M. Ellis, R. S. Faber, S. M. Fang, T. Fazio, G. G. Georgakakis, A. Gerke, B. F. Goss, W. M. Gwyn, S. Harker, J. Hopkins, A. M. Huang, J.-S. Ivison, R. J. Kassin, S. A. Kirby, E. N. Koekemoer, A. M. Koo, D. C. Laird, E. S. Le Floc'h, E. Lin, L. Lotz, J. M. Marshall, P. J. Martin, D. C. Metevier, A. J. Moustakas, L. A. Nandra, K. Noeske, K. G. Papovich, C. Phillips, A. C. Rich, R. M. Rieke, G. H. Rigopoulou, D. Salim, S. Schiminovich, D. Simard, L. Smail, I. Small, T. A. Weiner, B. J. Willmer, C. N. A. Willner, S. P. Wilson, G. Wright, E. L. Yan, R. TI The All-Wavelength Extended Groth Strip International Survey (AEGIS) data sets SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : photometry; infrared : galaxies; radio continuum : galaxies; surveys; ultraviolet : galaxies; X-rays : galaxies ID MULTIBAND IMAGING PHOTOMETER; FRANCE-HAWAII-TELESCOPE; ACTIVE GALACTIC NUCLEI; POINT-SOURCE CATALOGS; DEEP2 REDSHIFT SURVEY; STAR-FORMATION RATE; SPACE-TELESCOPE; SOURCE EXTRACTION; GALAXY EVOLUTION; WESTPHAL STRIP AB In this the first of a series of Letters, we present a panchromatic data set in the Extended Groth Strip region of the sky. Our survey, the All-Wavelength Extended Groth Strip International Survey (AEGIS), aims to study the physical properties and evolutionary processes of galaxies at. It includes the following deep, wide-field imaging data sets: z similar to 1 Chandra/ACIS X-ray, GALEX ultraviolet, CFHT/MegaCam Legacy Survey optical, CFHT/CFH12K optical, Hubble Space Telescope/ACS optical and NICMOS near-infrared, Palomar/WIRC near-infrared, Spitzer/IRAC mid-infrared, Spitzer/MIPS far-infrared, and VLA radio continuum. In addition, this region of the sky has been targeted for extensive spectroscopy using the Deep Imaging Multi-Object Spectrograph (DEIMOS) on the Keck II 10 m telescope. Our survey is compared to other large multiwavelength surveys in terms of depth and sky coverage. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Calif Santa Cruz, Lick Observ, UCO, Santa Cruz, CA 95064 USA. Lawrence Berkeley Natl Lab, Inst Nucl & Particle Astrophys, Berkeley, CA 94720 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Royal Observ, United Kingdom Astron Technol Ctr, Edinburgh EH9 3HJ, Midlothian, Scotland. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Nottingham, Sch Phys & Astron, Nottingham NG9 2RD, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ London Imperial Coll Sci Technol & Med, London SW7 2BZ, England. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 3P6, Canada. Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Natl Taiwan Univ, Dept Phys, Taipei 106, Taiwan. Natl Opt Astron Observ, Tucson, AZ 85719 USA. Kavli Inst Particle Astrophys & Cosmol, Menlo Pk, CA 94025 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Univ Oxford, Dept Astrophys, Oxford OX1 3RH, England. Columbia Univ, Dept Astron, New York, NY 10027 USA. Assoc Canadian Univ Res Astron, Herzberg Inst Astrophys, Natl Res Council, Victoria, BC V9E 2E7, Canada. Univ Durham, Inst Computat Cosmol, Durham DH1 3LE, England. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. RP Davis, M (reprint author), Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA. EM mdavis@berkeley.edu RI Conselice, Christopher/B-4348-2013; Georgakakis, Antonis/K-4457-2013; Smail, Ian/M-5161-2013; Barmby, Pauline/I-7194-2016; Ivison, R./G-4450-2011; OI Georgakakis, Antonis/0000-0002-3514-2442; Koekemoer, Anton/0000-0002-6610-2048; Smail, Ian/0000-0003-3037-257X; Barmby, Pauline/0000-0003-2767-0090; Ivison, R./0000-0001-5118-1313; Conselice, Christopher/0000-0003-1949-7638; Weiner, Benjamin/0000-0001-6065-7483; Kirby, Evan/0000-0001-6196-5162; Moustakas, Leonidas/0000-0003-3030-2360 NR 60 TC 268 Z9 271 U1 3 U2 17 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP L1 EP L6 DI 10.1086/517931 PN 2 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162TP UT WOS:000246112700001 ER PT J AU Konidaris, NP Guhathakurta, P Bundy, K Coil, AL Conselice, CJ Cooper, MC Eisenhardt, PRM Huang, JS Ivison, RJ Kassin, SA Kirby, EN Lotz, JM Newman, JA Noeske, KG Rich, RM Small, TA Willmer, CNA Willner, SP AF Konidaris, N. P. Guhathakurta, P. Bundy, K. Coil, A. L. Conselice, C. J. Cooper, M. C. Eisenhardt, P. R. M. Huang, J.-S. Ivison, R. J. Kassin, S. A. Kirby, E. N. Lotz, J. M. Newman, J. A. Noeske, K. G. Rich, R. M. Small, T. A. Willmer, C. N. A. Willner, S. P. TI AEGIS: Galaxy spectral energy distributions from the X-ray to radio SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : general; infrared : galaxies; radio continuum : galaxies; ultraviolet : galaxies; X-rays : galaxies ID REDSHIFT SURVEY; SEQUENCE AB The All-Wavelength Extended Groth Strip International Survey (AEGIS) team presents broadband spectral energy distributions (SEDs), from X-ray to radio wavelengths, for 71 galaxies spanning the redshift range 0.55-1.16 (< z >) similar to 0.7). Galaxies with secure redshifts are selected from a small (22 arcmin(2)) subsection of the Keck/AzS DEIMOS Galaxy Redshift Survey in the Extended Groth Strip field that has also been targeted for deep panchromatic imaging by ultraviolet (120-250 nm), optical (360-900 nm), optical/near-infrared (440-1600 nm), near-infrared (1200-2200 nm), mid/far-infrared (3.6-70 mu m), and radio (6-20 cm). A typical galaxy in our sample is M-B = -19.82. The ultraviolet to mid-infrared portion of their SEDs are found to be bracketed by two stellar-only model SEDs: (1) an early burst followed by passive evolution and (2) a constant star formation rate since early times. This suggests that few of these galaxies are undergoing major starbursts. Approximately half the galaxies show a mid-to far-infrared excess relative to the model SEDs, consistent with thermal emission from interstellar dust. Two objects have power-law SEDs, indicating that they are dominated by active galactic nuclei; both are detected in X-rays. SEDs, from the ultraviolet to the infrared, follow expected trends: redder SEDs are associated with red, early-type morphology, and low [O II] emission, and vice versa for blue SEDs. C1 Univ Calif Santa Cruz, Lick Observ, UCO, Santa Cruz, CA 95064 USA. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Nottingham, Sch Phys & Astron, Nottingham NG9 2RD, England. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Royal Observ, Astron Technol Ctr, Edinburgh EH9 3HJ, Midlothian, Scotland. Natl Opt Astron Observ, Tucson, AZ 85719 USA. Lawrence Berkeley Natl Lab, Inst Nucl Particle Astrophys, Berkeley, CA 94720 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. CALTECH, Pasadena, CA 91125 USA. RP Konidaris, NP (reprint author), Univ Calif Santa Cruz, Lick Observ, UCO, Santa Cruz, CA 95064 USA. EM npk@ucolick.org; raja@ucolick.org; kbundy@astro.caltech.edu; acoil@as.arizona.edu; conselice@nottingham.ac.uk; cooper@astron.berkeley.edu; prme@kromos.jpl.nasa.gov; jhuang@cfa.harvard.edu; rji@roe.ac.uk; kassin@ucolick.org; ekirby@ucolick.org; lotz@noao.edu; janewman@lbl.gov; rmr@astro.ucla.edu; tas@astro.caltech.edu; cnaw@as.arizona.edu; swillner@cfa.harvard.edu RI Conselice, Christopher/B-4348-2013; Ivison, R./G-4450-2011; OI Ivison, R./0000-0001-5118-1313; Conselice, Christopher/0000-0003-1949-7638; Kirby, Evan/0000-0001-6196-5162 NR 14 TC 5 Z9 5 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP L7 EP L10 DI 10.1086/517929 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162TP UT WOS:000246112700002 ER PT J AU Moustakas, LA Marshall, P Newman, JA Coil, AL Cooper, MC Davis, M Fassnacht, CD Guhathakurta, P Hopkins, A Koekemoer, A Konidaris, NP Lotz, JM Willmer, CNA AF Moustakas, Leonidas A. Marshall, Phil Newman, Jeffrey A. Coil, Alison L. Cooper, Michael C. Davis, Marc Fassnacht, Christopher D. Guhathakurta, Puragra Hopkins, Andrew Koekemoer, Anton Konidaris, Nicholas P. Lotz, Jennifer M. Willmer, Christopher N. A. TI A strong-lens survey in AEGIS: The influence of large-scale structure SO ASTROPHYSICAL JOURNAL LA English DT Article DE gravitational lensing; galaxies : high-redshift; galaxies : individual (HST J141735+522646, HST J141820+523611, HST J141833+524352); large-scale structure of universe ID HUBBLE-SPACE-TELESCOPE; GALAXY REDSHIFT SURVEY; OPTICAL EINSTEIN RING; DIGITAL SKY SURVEY; LINE-OF-SIGHT; GRAVITATIONAL LENS; ACS SURVEY; DARK-MATTER; ENVIRONMENTS; EVOLUTION AB We report on a visual search for galaxy-scale strong gravitational lenses over 650 arcmin(2) of HST ACS (V-606 and I-814) imaging in the DEEP2 Extended Groth Strip. This field has Keck DEIMOS spectroscopy of similar to 14,000 galaxies (similar to 75% complete to). We identify three strong galaxy-galaxy lenses: HST J141735 + 522646 is a previously known four-image lens (the "Cross"; z(1) = 0.8106, z(s) = 3.40); HST J141820 + 523611 (the "Dew-drop"; z(l) = 0.5798, z(s) = 0.9818) features two pairs of arcs; and HST J141833 + 524352 (the "Anchor"; z(l) = 0.4625, no z(s)) has one pair of arcs. Based on a normalized local density (1 + delta(3)), lenses are found to be in both under- and overdense local environments. All three lenses are fit well by singular isothermal ellipsoid models including external shear, with chi(2)(p) similar to 1. The model shears are similar to 10%. Approximating all line-of-sight galaxies as singular isothermal sphere halos truncated at 200 h(-1) kpc, with masses estimated through the Faber- Jackson relation, infers shears of similar to 2%, much smaller than those required by the models. Therefore, the corresponding convergence estimates must also be suspect. If more realistic treatment of galaxies (and the large-scale structure that they are embedded in) were to match the inferred shears to the model shears, then the true convergence could be measured and the mass-sheet degeneracy broken. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Kavli Inst Particle Astrophys & Cosmol, Stanford, CA 94309 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Inst Nucl & Particle Astrophys, Berkeley, CA 94720 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Calif Santa Cruz, Lick Observ, UCO, Santa Cruz, CA 95064 USA. Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Natl Opt Astron Observ, Tucson, AZ 85719 USA. RP Moustakas, LA (reprint author), CALTECH, Jet Prop Lab, MS 169-327, Pasadena, CA 91109 USA. EM leonidas@jpl.nasa.gov OI Konidaris, Nicholas/0000-0003-1905-2815; Moustakas, Leonidas/0000-0003-3030-2360; Koekemoer, Anton/0000-0002-6610-2048 NR 45 TC 33 Z9 33 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2007 VL 660 IS 1 BP L31 EP L34 DI 10.1086/517930 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162TP UT WOS:000246112700008 ER PT J AU Cowings, P Toscano, W DeRoshta, C Taylor, B Hines, A Bright, A Dodds, A AF Cowings, Patricia Toscano, William DeRoshta, Charles Taylor, Bruce Hines, A'Liah Bright, Andrew Dodds, Anika TI Converging indicators for assessing individual differences in adaptation to extreme environments SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE performance; perception; self-reports; physiological measures; behavioral health; sleep deprivation; motion sickness; hypergravity ID MOTION SICKNESS SUSCEPTIBILITY; FEEDBACK TRAINING EXERCISE; SLEEP-DEPRIVATION; TASK-PERFORMANCE; SPACE; MOOD; PROMETHAZINE; CENTRIFUGE; SYMPTOMS; BATTERY AB It is well known that microgravity results in various physiological alterations, for example, head-ward fluid shifts which can impede physiological adaptation. Other factors that may affect crew operational efficiency include disruption of sleep-wake cycles, high workload, isolation, confinement, stress, and fatigue. From an operational perspective, it is difficult to predict which individuals will be most or least affected in this unique environment given that most astronauts are first-time flyers. During future lunar and Mars missions space crews will include both men and women of multi-national origins, different professional backgrounds, and various states of physical condition. Therefore, new methods or technologies are needed to monitor and predict astronaut performance and health, and to evaluate the effects of various countermeasures on crew during long-duration missions. Herein we describe the development and validation of a new methodology for assessing the deleterious effects of spaceflight on crew health and performance. We reviewed several studies conducted in both laboratory and operational environments with men and women ranging in age between 18 to 50 yr. The studies included the following: soldiers performing command and control functions during mobile operations in enclosed armored vehicles; subjects participating in laboratory tests of an anti-motion sickness medication; subjects exposed to chronic hyper-gravity aboard a centrifuge; and subject responses to 36-h of sleep deprivation. Physiological measurements, performance metrics, and subjective self-reports were collected in each study. The results demonstrate that multivariate converging indicators provide a significantly more reliable method for assessing environmental effects on performance and health than any single indicator. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Cowings, P (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM Patricia.S.Cowing@nasa.gov NR 74 TC 6 Z9 8 U1 0 U2 10 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD MAY PY 2007 VL 78 IS 5 SU S BP B195 EP B215 PG 21 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 167OK UT WOS:000246460800029 PM 17547321 ER PT J AU Fischer, U McDonnell, L Orasanu, J AF Fischer, Ute McDonnell, Lori Orasanu, Judith TI Linguistic correlates of team performance: Toward a tool for monitoring team functioning during space missions SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article; Proceedings Paper CT 7th International Conference on Naturalistic Decision Making CY JUN 15-17, 2005 CL Amsterdam, NETHERLANDS DE team work; team processes; task-related and social aspects of team communication ID COMMUNICATION; ENVIRONMENTS AB Introduction: Approaches to mitigating the likelihood of psychosocial problems during space missions emphasize preflight measures such as team training and team composition. Additionally, it may be necessary to monitor team interactions during missions for signs of interpersonal stress. The present research was conducted to identify features in team members' communications indicative of learn functioning. Methods: Team interactions were studied in the context of six computer-simulated search and rescue missions. There were 12 teams of 4 U.S. men who participated; however, the present analyses contrast the top two teams with the two least successful teams. Communications between team members were analyzed using linguistic analysis software and a coding scheme developed to characterize task-related and social dimensions of team interactions. Coding reliability was established by having two raters independently code three transcripts. Between-rater agreement ranged from 78.1 to 97.9%. Results: Team performance was significantly associated with team members' task-related communications, specifically with the extent to which task-critical information was shared. Successful and unsuccessful teams also showed different interactive patterns, in particular concerning the frequencies of elaborations and no-responses. Moreover, task success was negatively correlated with variability in team members' word count, and positively correlated with the number of positive emotion words and the frequency of assenting relative to dissenting responses. Conclusions: Analyses isolated certain task-related and social features of team communication related to team functioning. Team success was associated with the extent to which team members shared task-critical information, equally participated and built on each other's contributions, showed agreement, and positive affect. C1 Georgia Inst Technol, Sch Lit Commun & Culture, Atlanta, GA 30332 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Fischer, U (reprint author), Georgia Inst Technol, Sch Lit Commun & Culture, 686 Cherry St, Atlanta, GA 30332 USA. EM ute.fischer@gatech.edu NR 50 TC 8 Z9 9 U1 1 U2 7 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD MAY PY 2007 VL 78 IS 5 SU S BP B86 EP B95 PG 10 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 167OK UT WOS:000246460800013 PM 17547309 ER PT J AU Pastor, JY Ridruejo, A Llorca, J Sayir, A Orera, VM AF Pastor, J. Y. Ridruejo, A. Llorca, J. Sayir, A. Orera, Victor M. TI Environmental degradation of the mechanical properties of single-crystal erbia-doped zircona fibers SO BOLETIN DE LA SOCIEDAD ESPANOLA DE CERAMICA Y VIDRIO LA Spanish DT Article; Proceedings Paper CT 8th National Meeting of Electroceramica CY JUN 24-26, 2007 CL Univ Aveiro, Aveiro, PORTUGAL HO Univ Aveiro DE zircona; erbia; tetragonal structure; environmental susceptibility; slow crack growth; stress-corrosion cracking ID SLOW CRACK-GROWTH; HYDROTHERMAL DEGRADATION; TETRAGONAL ZIRCONIA; TENSILE-STRENGTH; Y-TZP; TRANSFORMATION; CERAMICS; SYSTEM; SAPPHIRE; WATER AB The flexure strength of tetragonal ZrO2 (Er2O3) single-crystal monofilaments manufactured by the laser-heated floating zone method was measured as a function of the environment (air vs. water) and temperature (from 25 to 800 degrees C) at loading rates spanning three orders of magnitude to ascertain their susceptibility to the environmental conditions. These mechanical tests were completed with parallel tests on fully-annealed monofilarnents (to relieve the thermal residual stresses induced during growth) and by detailed analysis of the fracture surfaces using scanning electron microscopy and micro-Raman spectroscopy. While environmental susceptibility of ZrO2 (Y2O3) in previous investigations was always associated with the destabilization of the tetragonal phase, monoclinic phase was not detected on the fracture surfaces of the ZrO2 (Er2O3) monofilaments and it was concluded that slow crack growth in this material at high temperature or immersed in water was due to stress-corrosion cracking. C1 Univ Politecn Madrid, Dept Ciencia Mat, ETS Ingn Caminos Canales & Puertos, E-28040 Madrid, Spain. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Zaragoza, Inst Ciencia Mat Aragon, CSIC, E-50009 Zaragoza, Spain. RP Pastor, JY (reprint author), Univ Politecn Madrid, Dept Ciencia Mat, ETS Ingn Caminos Canales & Puertos, E-28040 Madrid, Spain. RI LLorca, Javier/C-1140-2013; orera, Victor/A-4213-2011; Ridruejo, Alvaro/I-1082-2015 OI LLorca, Javier/0000-0002-3122-7879; Ridruejo, Alvaro/0000-0002-8327-6090 NR 28 TC 0 Z9 0 U1 1 U2 8 PU SOCIEDAD ESPANOLA CERAMICA VIDRIO PI MADRID PA DESPACHO 176, INSTITUTO CERAMICA VIDRIO, CSIC, C-KELSEN 5, 28049 MADRID, SPAIN SN 0366-3175 J9 BOL SOC ESP CERAM V JI Bol. Soc. Esp. Ceram. Vidr. PD MAY-JUN PY 2007 VL 46 IS 3 BP 131 EP 137 PG 7 WC Materials Science, Ceramics SC Materials Science GA 183YS UT WOS:000247608900006 ER PT J AU Mishchenko, MI Cairns, B Kopp, G Schueler, CF Fafaul, BA Hansen, JE Hooker, RJ Itchkawich, T Maring, HB Travis, LD AF Mishchenko, Michael I. Cairns, Brian Kopp, Greg Schueler, Carl F. Fafaul, Bryan A. Hansen, James E. Hooker, Ronald J. Itchkawich, Tom Maring, Hal B. Travis, Larry D. TI Accurate monitoring of terrestrial aerosols and total solar irradiance - Introducing the glory mission SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID RESEARCH SCANNING POLARIMETER; CLIMATE-CHANGE; SATELLITE RETRIEVAL; POLARIZATION MEASUREMENTS; SCIENTIFIC OBJECTIVES; REFLECTED SUNLIGHT; OPTICAL DEPTH; A-TRAIN; OCEAN; VARIABILITY AB The NASA Glory mission is intended to facilitate and improve upon long-term monitoring of two key forcings influencing global climate. One of the mission's principal objectives is to determine the global distribution of detailed aerosol and cloud properties with unprecedented accuracy, thereby facilitating the quantification of the aerosol direct and indirect radiative forcings. The other is to continue the 28-yr record of satellite-based measurements of total solar irradiance from which the effect of solar variability on the Earth's climate is quantified. These objectives will be met by flying two state-of-the-art science instruments on an Earth-orbiting platform. Based on a proven technique demonstrated with an aircraft-based prototype, the Aerosol Polarimetry Sensor (APS) will collect accurate multiangle photopolarimetric measurements of the Earth along the satellite ground track within a wide spectral range extending from the visible to the shortwave infrared. The Total Irradiance Monitor (TIM) is an improved version of an instrument currently flying on the Solar Radiation and Climate Experiment (SORCE) and will provide accurate and precise measurements of spectrally integrated sunlight illuminating the Earth. Because Glory is expected to fly as part of the A-Train constellation of Earth-orbiting spacecraft, the APS data will also be used to improve retrievals of aerosol climate forcing parameters and global aerosol assessments with other A-Train instruments. In this paper, we detail the scientific rationale and objectives of the Glory mission, explain how these scientific objectives dictate the specific measurement strategy, describe how the measurement strategy will be implemented by the APS and TIM, and briefly outline the overall structure of the mission. It is expected that the Glory results will be used extensively by members of the climate, solar, atmospheric, oceanic, and environmental research communities as well as in education and outreach activities. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA. Raytheon Santa Barbara Remote Sensing, Goleta, CA USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA Headquarters, Washington, DC USA. Orbital Sci Corp, Dulles, VA USA. RP Mishchenko, MI (reprint author), NASA, Goddard Inst Space Studies, 2880 Boradway, New York, NY 10025 USA. EM mmishchenko@giss.nasa.gov RI Mishchenko, Michael/D-4426-2012 NR 62 TC 155 Z9 159 U1 2 U2 23 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAY PY 2007 VL 88 IS 5 BP 677 EP + DI 10.1175/BAMS-88-5-677 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 175CQ UT WOS:000246990600016 ER PT J AU Zak, M AF Zak, Michail TI Complexity for survival of livings SO CHAOS SOLITONS & FRACTALS LA English DT Article AB A connection between survivability of livings and complexity of their behavior is established. New physical paradigms-exchange of information via reflections, and chain of abstraction s-explaining and describing progressive evolution of complexity in living (active) systems are introduced. A biological origin of these paradigms is associated with a recently discovered mirror neuron that is able to learn by imitation. As a result, an active element possesses the self-nonself images and interacts with them creating the world of mental dynamics. Three fundamental types of complexity of mental dynamics that contribute to survivability are identified. Mathematical model of the corresponding active systems is described by coupled motor-mental dynamics represented by Langevin and Fokker-Planck equations, respectively, while the progressive evolution of complexity is provided by nonlinear evolution of probability density. Application of the proposed formalism to modeling common-sense-based decision-making process is discussed. (c) 2005 Elsevier Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Adv Comp Algorithms & IVHM Grp, Pasadena, CA 91109 USA. RP Zak, M (reprint author), CALTECH, Jet Prop Lab, Adv Comp Algorithms & IVHM Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Michail.Zak@jpl.nasa.gov NR 8 TC 2 Z9 2 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0960-0779 J9 CHAOS SOLITON FRACT JI Chaos Solitons Fractals PD MAY PY 2007 VL 32 IS 3 BP 1154 EP 1167 DI 10.1016/j.chaos.2005.11.052 PG 14 WC Mathematics, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA 128SQ UT WOS:000243679300029 ER PT J AU Meador, MAB Capadona, LA McCorkle, L Papadopoulos, DS Leventis, N AF Meador, Mary Ann B. Capadona, Lynn A. McCorkle, Linda Papadopoulos, Demetrios S. Leventis, Nicholas TI Structure-property relationships in porous 3D nanostructures as a function of preparation conditions: Isocyanate cross-linked silica aerogels SO CHEMISTRY OF MATERIALS LA English DT Article ID THERMAL-DIFFUSIVITY; FLASH METHOD; LOW-DENSITY; COMPOSITE; CONDUCTIVITY; TEMPERATURES AB Sol-gel-derived silica aerogels are attractive candidates for many unique thermal, optical, catalytic, and chemical applications because of their low density and high mesoporosity. However, their inherent fragility has restricted use of aerogel monoliths to applications in which they are not subject to any load. We have previously reported cross-linking of the mesoporous silica structure of aerogels with di-isocyanates, styrenes, or epoxies reacting with amine-decorated silica surfaces. These approaches have been shown to significantly increase the strength of aerogels with only a small effect on density or porosity. Though density is a prime predictor of properties such as strength and thermal conductivity for aerogels, it is becoming clear from previous studies that varying the silica backbone and size of the polymer cross-link independently can give rise to combinations of properties that cannot be predicted from density alone. Herein, we examine the effects of four processing parameters for producing this type of polymer cross-linked aerogel on properties of the resulting monoliths. We focus on the results of C-13 CP-MAS NMR, which gives insight to the size and structure of polymer cross-link present in the monoliths and relates the size of the cross-links to microstructure, mechanical properties, and other characteristics of the materials obtained. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Meador, MAB (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM maryann.meador@nasa.gov; lynn.a.capadona@nasa.gov OI Meador, Mary Ann/0000-0003-2513-7372 NR 22 TC 90 Z9 95 U1 13 U2 87 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD MAY 1 PY 2007 VL 19 IS 9 BP 2247 EP 2260 DI 10.1021/cm070102p PG 14 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 159XC UT WOS:000245900100017 ER PT J AU Bell, ML Goldberg, R Hogrefe, C Kinney, PL Knowlton, K Lynn, B Rosenthal, J Rosenzweig, C Patz, JA AF Bell, Michelle L. Goldberg, Richard Hogrefe, Christian Kinney, Patrick L. Knowlton, Kim Lynn, Barry Rosenthal, Joyce Rosenzweig, Cynthia Patz, Jonathan A. TI Climate change, ambient ozone, and health in 50 US cities SO CLIMATIC CHANGE LA English DT Article ID AIR-QUALITY STANDARDS; VECTOR-BORNE DISEASE; HOSPITAL ADMISSIONS; UNITED-STATES; TIME-SERIES; POLLUTION; MORTALITY; MODEL; METAANALYSIS; TEMPERATURE AB We investigated how climate change could affect ambient ozone concentrations and the subsequent human health impacts. Hourly concentrations were estimated for 50 eastern US cities for five representative summers each in the 1990s and 2050s, reflecting current and projected future climates, respectively. Estimates of future concentrations were based on the IPCC A2 scenario using global climate, regional climate, and regional air quality models. This work does not explore the effects of future changes in anthropogenic emissions, but isolates the impact of altered climate on ozone and health. The cities' ozone levels are estimated to increase under predicted future climatic conditions, with the largest increases in cities with present-day high pollution. On average across the 50 cities, the summertime daily 1-h maximum increased 4.8 ppb, with the largest increase at 9.6 ppb. The average number of days/summer exceeding the 8-h regulatory standard increased 68%. Elevated ozone levels correspond to approximately a 0.11% to 0.27% increase in daily total mortality. While actual future ozone concentrations depend on climate and other influences such as changes in emissions of anthropogenic precursors, the results presented here indicate that with other factors constant, climate change could detrimentally affect air quality and thereby harm human health. C1 Yale Univ, Sch Forestry & Environm Studies, New Haven, CT 06511 USA. Columbia Univ, Ctr Climate Syst Res, New York, NY 10027 USA. SUNY Albany, Atmospher Sci Res Ctr, Albany, NY 12222 USA. Columbia Univ, Mailman Sch Publ Hlth, New York, NY 10027 USA. NASA, Goddard Inst Space Studies, Natl Aeronaut & Space Adm, New York, NY 10025 USA. Univ Wisconsin, Nelson Inst Environm Studies, Madison, WI 53706 USA. RP Bell, ML (reprint author), Yale Univ, Sch Forestry & Environm Studies, 205 Prospect St, New Haven, CT 06511 USA. EM michelle.bell@yale.edu RI Kinney, Patrick/H-7914-2012 NR 62 TC 132 Z9 137 U1 10 U2 58 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 2007 VL 82 IS 1-2 BP 61 EP 76 DI 10.1007/s10584-006-9166-7 PG 16 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 154PZ UT WOS:000245521100004 ER PT J AU Jacob, D Barring, L Christensen, OB Christensen, JH de Castro, M Deque, M Giorgi, F Hagemann, S Hirschi, M Jones, R Kjellstrom, E Lenderink, G Rockel, B Sanchez, E Schar, C Seneviratne, SI Somot, S van Ulden, A van den Hurk, B AF Jacob, Daniela Barring, Lars Christensen, Ole Bossing Christensen, Jens Hesselbjerg de Castro, Manuel Deque, Michel Giorgi, Filippo Hagemann, Stefan Hirschi, Martin Jones, Richard Kjellstrom, Erik Lenderink, Geert Rockel, Burkhardt Sanchez, Enrique Schaer, Christoph Seneviratne, Sonia I. Somot, Samuel van Ulden, Aad van den Hurk, Bart TI An inter-comparison of regional climate models for Europe: model performance in present-day climate SO CLIMATIC CHANGE LA English DT Article ID GENERAL-CIRCULATION MODEL; TERRESTRIAL WATER STORAGE; SOIL-MOISTURE MEMORY; PARAMETERIZATION SCHEMES; AIR-TEMPERATURE; SURFACE CLIMATE; SIMULATION; CLOUD; ATMOSPHERE; RADIATION AB The analysis of possible regional climate changes over Europe as simulated by 10 regional climate models within the context of PRUDENCE requires a careful investigation of possible systematic biases in the models. The purpose of this paper is to identify how the main model systematic biases vary across the different models. Two fundamental aspects of model validation are addressed here: the ability to simulate (1) the long-term (30 or 40 years) mean climate and (2) the inter-annual variability. The analysis concentrates on near-surface air temperature and precipitation over land and focuses mainly on winter and summer. In general, there is a warm bias with respect to the CRU data set in these extreme seasons and a tendency to cold biases in the transition seasons. In winter the typical spread (standard deviation) between the models is 1 K. During summer there is generally a better agreement between observed and simulated values of inter-annual variability although there is a relatively clear signal that the modeled temperature variability is larger than suggested by observations, while precipitation variability is closer to observations. The areas with warm (cold) bias in winter generally exhibit wet (dry) biases, whereas the relationship is the reverse during summer (though much less clear, coupling warm (cold) biases with dry (wet) ones). When comparing the RCMs with their driving GCM, they generally reproduce the large-scale circulation of the GCM though in some cases there are substantial differences between regional biases in surface temperature and precipitation. C1 [Jacob, Daniela; Hagemann, Stefan] Max Planck Inst Meteorol, D-20146 Hamburg, Germany. [Christensen, Ole Bossing; Christensen, Jens Hesselbjerg] Danish Meteorol Inst, DK-2100 Copenhagen, Denmark. [Hirschi, Martin; Schaer, Christoph] ETH, Inst Atmospher & Climate Sci, CH-8057 Zurich, Switzerland. [Seneviratne, Sonia I.] NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. [Barring, Lars; Kjellstrom, Erik] Swedish Meteorol & Hydrol Inst, Rossby Ctr, S-60176 Norrkoping, Sweden. [Lenderink, Geert; van Ulden, Aad; van den Hurk, Bart] Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. [Rockel, Burkhardt] GKSS Forschungszentrum Geesthacht, D-21502 Geesthacht, Germany. [Deque, Michel; Somot, Samuel] Meteo France CNRM, F-31057 Toulouse, France. [Jones, Richard] Univ Reading, Met Off Hadley Ctr, Reading Unit, Reading RG6 6BB, Reading, Berks, England. [Giorgi, Filippo] Abdus Salam Int Ctr Theoret Phys, I-34100 Trieste, Italy. [de Castro, Manuel; Sanchez, Enrique] Univ Castilla La Mancha, Fac Ciencias Medio Ambiente, Toledo 45071, Spain. RP Jacob, D (reprint author), Max Planck Inst Meteorol, Bundesstr 55, D-20146 Hamburg, Germany. EM daniela.jacob@zmaw.de RI Schar, Christoph/A-1033-2008; Seneviratne, Sonia/G-8761-2011; Giorgi, Filippo/C-3169-2013; Christensen, Jens/C-4162-2013; Christensen, Ole/E-4417-2013; Sanchez, Enrique/L-5086-2014 OI Schar, Christoph/0000-0002-4171-1613; Seneviratne, Sonia/0000-0001-9528-2917; Somot, Samuel/0000-0002-5066-2921; Kjellstrom, Erik/0000-0002-6495-1038; lenderink, geert/0000-0002-1572-4867; Christensen, Jens/0000-0002-9908-8203; Sanchez, Enrique/0000-0002-7720-4437 NR 89 TC 407 Z9 412 U1 4 U2 55 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0165-0009 EI 1573-1480 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 2007 VL 81 SU 1 BP 31 EP 52 DI 10.1007/s10584-006-9213-4 PG 22 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 182UL UT WOS:000247529400003 ER PT J AU Morscher, GN Singh, M Kiser, JD Freedman, M Bhatt, R AF Morscher, Gregory N. Singh, Mrityunjay Kiser, J. Douglas Freedman, Marc Bhatt, Ram TI Modeling stress-dependent matrix cracking and stress-strain behavior in 2D woven SiC fiber reinforced CVISiC composites SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article DE ceramic-matrix composites; matrix cracking; acoustic emission; stress-strain behavior ID SIC/SIC COMPOSITES; BRITTLE AB 2D woven Hi-Nicalon and Sylramic-iBN SiC fiber reinforced chemical vapor-infiltrated (CVI) SiC matrix composites were tested at room temperature with modal acoustic emission monitoring in order to determine relationships for stress-dependent matrix cracking. The Hi-Nicalon composites varied in the number of plies (1-36), specimen thickness, and constituent content. The Sylramic-iBN composites were fabricated with balanced and unbalanced 2D weaves in order to vary the fiber volume fraction in the orthogonal directions. Not surprisingly, matrix cracking stresses tended to be, but were not always, higher for composites with higher fiber volume fractions in the loading direction. It was demonstrated that simple relationships for stress-dependent matrix cracking could be related to the stress in the load-bearing CVI SiC matrix. For low-density composites, the 90 degrees minicomposites do not share significant loads and matrix cracking was very similar to single tow minicomposites. For higher-density composites, where significant load is carried by the 0 degrees minicomposites, matrix cracking was dependent on the unbridged "flaw" size, i.e., the 90 degrees tow size or unbridged transverse crack size. (c) 2006 Elsevier Ltd. All rights reserved. C1 NASA, Glenn Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. NASA, Glenn Res Ctr, QSS Grp, Cleveland, OH USA. USA, NASA, Glenn Res Ctr, Cleveland, OH USA. RP Morscher, GN (reprint author), NASA, Glenn Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. EM Gregory.N.Morscher@grc.nasa.gov NR 14 TC 33 Z9 39 U1 2 U2 18 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PD MAY PY 2007 VL 67 IS 6 BP 1009 EP 1017 DI 10.1016/j.compscitech.2006.06.007 PG 9 WC Materials Science, Composites SC Materials Science GA 149RB UT WOS:000245163200009 ER PT J AU Nallasamy, M Hixon, R Sawyer, S AF Nallasamy, M. Hixon, R. Sawyer, S. TI Solution of unsteady Euler equations: Gust-cascade interaction tones SO COMPUTERS & FLUIDS LA English DT Article ID RUNGE-KUTTA SCHEMES; COMPUTATIONAL ACOUSTICS; BOUNDARY-CONDITIONS; LOW-DISSIPATION; MEAN FLOWS; NOISE; DUCTS AB The problem of interaction of a vortical gust with a two-dimensional cascade is considered. Full nonlinear time dependent Euler equations governing the flow are solved employing a 6th-order accurate spatial differencing scheme and a 4th-order accurate time marching technique. The vortical gust is represented by a Fourier series which includes three harmonics. The acoustic response of the cascade for single and multi frequency (vortical) excitations are calculated. The solutions show the generation and propagation of modes that are expected from the theory. It is demonstrated that at low amplitudes of excitation, the time domain analysis produces characteristics of the propagating modes such as the complex mode amplitudes, phase variations, axial waveforms, and tangential waveforms that are in very good agreement with those expected from the linear theory. The exponential decay of the cutoff modes of the first harmonic is also clearly observed. The sound pressure levels of the propagating modes obtained from the present nonlinear time domain analysis are compared with the results of a linearized Navier-Stokes solution and a linearized Euler solution (frequency domain analyses) and good agreement between the results is observed for all the propagating modes. (c) 2006 Published by Elsevier Ltd. C1 NASA, Glenn Res Ctr, QSS Grp Inc, Cleveland, OH 44135 USA. Univ Toledo, Dept Mech Engn, Toledo, OH 43606 USA. Univ Akron, Dept Mech Engn, Akron, OH 44325 USA. RP Nallasamy, M (reprint author), Mail Code ASRC-23, Kennedy Space Ctr, FL 32899 USA. EM mnallasamy@yahoo.com NR 25 TC 6 Z9 6 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PD MAY PY 2007 VL 36 IS 4 BP 724 EP 741 DI 10.1016/j.compfluid.2006.06.002 PG 18 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA 139DS UT WOS:000244413100006 ER PT J AU Tremblay, LB Holland, MM Gorodetskaya, IV Schmidt, GA AF Tremblay, L. Bruno Holland, Marika M. Gorodetskaya, Irina V. Schmidt, Gavin A. TI An ice-free arctic? Opportunities for computational science SO COMPUTING IN SCIENCE & ENGINEERING LA English DT Article ID SEA-ICE; CLIMATE-CHANGE; OCEAN; VARIABILITY; MODELS; COVER; WATER AB The authors discuss modeling's role in understanding the ice-ocean system, as well as its importance in predicting the future state of Arctic sea ice. In doing so, this article presents results from a hierarchy of models of different complexity, their strengths and weaknesses, and how they could help forecast the future state of the ice-ocean system. C1 McGill Univ, Montreal, PQ H3A 2T5, Canada. Columbia Univ, Lamont Doherty Earth Observ, New York, NY 10027 USA. US Natl Ctr Atmospher Res NCAR, Boulder, CO USA. Columbia Univ, Dept Earth & Environm Sci, New York, NY 10027 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Tremblay, LB (reprint author), McGill Univ, Montreal, PQ H3A 2T5, Canada. EM bruno.tremblay@mcgill.ca; mholland@ucar.edu; irina@ldeo.columbia.edu; gschmidt@giss.nasa.gov RI Schmidt, Gavin/D-4427-2012; Tremblay, Bruno/I-4497-2012; Gorodetskaya, Irina/K-1987-2015 OI Schmidt, Gavin/0000-0002-2258-0486; Gorodetskaya, Irina/0000-0002-2294-7823 NR 35 TC 3 Z9 3 U1 0 U2 7 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1521-9615 J9 COMPUT SCI ENG JI Comput. Sci. Eng. PD MAY-JUN PY 2007 VL 9 IS 3 BP 65 EP 74 DI 10.1109/MCSE.2007.45 PG 10 WC Computer Science, Interdisciplinary Applications SC Computer Science GA 156RY UT WOS:000245668100015 ER PT J AU Hutzler, NR Penanen, KI Chui, TCP AF Hutzler, Nicholas R. Penanen, Konstantin I. Chui, Talso C. P. TI Low temperature, high frequency permeability and its potential for use as a core material of Metglas 2714A for EMI filters SO CRYOGENICS LA English DT Article DE magnetic material; cryogenics; high-permeability; EMI filter AB We report the measurement of the relative permeability of Metglas 2714A at 4.2 K temperature and at frequencies up to 1 MHz. We find that at similar to 300 kHz, the real part of the relative permeability begins to drop towards unity, while the magnitude of the imaginary part increases. Our data can be used to design transformers and EMI filters for low temperature applications. (c) 2007 Published by Elsevier Ltd. C1 CALTECH, Jet Prop Lab, Low Temp Sci & Quantum Sensor Grp, Pasadena, CA 91109 USA. RP Chui, TCP (reprint author), CALTECH, Jet Prop Lab, Low Temp Sci & Quantum Sensor Grp, 4800 Oak Grove Dr,Mail Stop 79-24, Pasadena, CA 91109 USA. EM talso.c.chui@jpl.nasa.gov NR 1 TC 1 Z9 1 U1 1 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD MAY-JUN PY 2007 VL 47 IS 5-6 BP 279 EP 281 DI 10.1016/j.cryogenics.2007.03.004 PG 3 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 202DE UT WOS:000248881400001 ER PT J AU Rankenburg, K Brandon, AD Humayun, M AF Rankenburg, K. Brandon, A. D. Humayun, M. TI Osmium isotope systematics of ureilites SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID U-TH-PB; PARENT-BODY; TRACE-ELEMENT; POLYMICT UREILITE; IRON-METEORITES; SM-ND; TERRESTRIAL CONTAMINATION; CARBONACEOUS CHONDRITES; SIDEROPHILE ELEMENTS; EXPLOSIVE VOLCANISM AB The Os-187/Os-188 for 22 ureilite whole rock samples, including monomict, augite-bearing, and polymict lithologies, were examined in order to constrain the provenance and subsequent magmatic processing of the ureilite parent body (or bodies). The Re/Os ratios of most ureilites show evidence for a recent disturbance, probably related to Re mobility during weathering, and no meaningful chronological information can be extracted from the present data set. The ureilite Os-187/Os-188 ratios span a range from 0.11739 to 0.13018, with an average of 0.1258 +/- 0.0023 (1 sigma), similar to typical carbonaceous chondrites, and distinct from ordinary or enstatite chondrites. The similar mean Of Os-187/Os-188 measured for the ureilites and carbonaceous chondrites suggests that the ureilite parent body probably formed within the same region of the solar nebula as carbonaceous chondrites. From the narrow range of the Os-187/Os-188 distribution in ureilite meteorites it is further concluded that Re was not significantly fractionated from Os during planetary differentiation and was not lost along with the missing ureilitic melt component. The lack of large Re/Os fractionations requires that Re/Os partitioning was controlled by a metal phase, and thus metal had to be stable throughout the interval of magmatic processing on the ureilite parent body. (C) 2007 Elsevier Ltd. All rights reserved. C1 Florida State Univ, Dept Geol Sci, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Rankenburg, K (reprint author), Florida State Univ, Dept Geol Sci, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. EM Rankenburg@magnet.fsu.edu RI Humayun, Munir/A-1247-2007; OI Humayun, Munir/0000-0001-8516-9435 NR 93 TC 24 Z9 24 U1 2 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY 1 PY 2007 VL 71 IS 9 BP 2402 EP 2413 DI 10.1016/j.gca.2007.02.015 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 163NE UT WOS:000246165800016 ER PT J AU Carn, SA Krueger, AJ Krotkov, NA Yang, K Levelt, PF AF Carn, S. A. Krueger, A. J. Krotkov, N. A. Yang, K. Levelt, P. F. TI Sulfur dioxide emissions from Peruvian copper smelters detected by the Ozone Monitoring Instrument SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID POLLUTION; CONVERSION; CHEMISTRY; SULFATE; SO2 AB We report the first daily observations of sulfur dioxide (SO2) emissions from copper smelters by a satellite-borne sensor - the Ozone Monitoring Instrument (OMI) on NASA's EOS/ Aura spacecraft. Emissions from two Peruvian smelters (La Oroya and Ilo) were detected in up to 80% of OMI overpasses between September 2004 and June 2005. SO2 production by each smelter in this period is assessed and compared with contemporaneous emissions from active volcanoes in Ecuador and southern Colombia. Annual SO2 discharge from the Ilo smelter, La Oroya smelter, and volcanoes in 2004 - 2005 is estimated and amounts to 0.3(-0.1)(+0.2), 0.07 +/- 0.03, and 1.2 +/- 0.5 Tg, respectively. This study confirms OMI's potential as an effective tool for evaluation of anthropogenic and natural SO2 emissions. Smelter plumes transport an array of toxic metals in addition to SO2 and continued monitoring to mitigate health and environmental impacts is recommended. C1 Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. RP Carn, SA (reprint author), Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. EM scarn@umbc.edu RI Krotkov, Nickolay/E-1541-2012 OI Krotkov, Nickolay/0000-0001-6170-6750 NR 19 TC 69 Z9 75 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 2007 VL 34 IS 9 AR L09801 DI 10.1029/2006GL029020 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 165LA UT WOS:000246305800001 ER PT J AU Nixon, CA Achterberg, RK Conrath, BJ Irwin, PGJ Teanby, NA Fouchet, T Parrish, PD Romani, PN Abbas, M LeClair, A Strobel, D Simon-Miller, AA Jennings, DJ Flasar, FM Kunde, VG AF Nixon, C. A. Achterberg, R. K. Conrath, B. J. Irwin, P. G. J. Teanby, N. A. Fouchet, T. Parrish, P. D. Romani, P. N. Abbas, M. LeClair, A. Strobel, D. Simon-Miller, A. A. Jennings, D. J. Flasar, F. M. Kunde, V. G. TI Meridional variations of C2H2 and C2H6 in Jupiter's atmosphere from Cassini CIRS infrared spectra SO ICARUS LA English DT Article DE Jupiter, atmosphere; abundances, atmospheres; atmospheres, composition; infrared observations; spectroscopy ID PROBE MASS-SPECTROMETER; LONG-TERM EVOLUTION; JOVIAN ATMOSPHERE; SPECTROSCOPIC DATABASE; ABSORPTION-SPECTRA; THERMAL PROFILES; LINE PARAMETERS; CLOUD STRUCTURE; HOT-SPOT; STRATOSPHERE AB Hydrocarbons such as acetylene (C2H2) and ethane (C2H6) are important tracers in Jupiter's atmosphere, constraining our models of the chemical and dynamical processes. However, our knowledge of the vertical and meridional variations of their abundances has remained sparse. During the flyby of the Cassim spacecraft in December 2000, the Composite Infrared Spectrometer (CIRS) instrument was used to map the spatial variation of ennssions from 10 to 1400 cm(-1) (1000-7 mu m). In this paper we analyze a zonally averaged set of CIRS spectra taken at the highest (0.48 cm(-1)) resolution, firstly to infer atmospheric temperatures in the stratosphere at 0.5-20 mbar via the v(4) band of CH4, and in the troposphere at 150-400 mbar. via the H-2 absorption at 600-800 cm(-1). Stratospheric temperatures at 5 mbar are generally warmer in the north than the south by 7-8 K. while tropospheric temperatures show no such asymmetry. Both latitudinal temperature profiles however do show a pattern of maxima and minima which are largely anti-correlated between the two levels. We then use the derived temperature profiles to infer the vertical abundances of C2H2) and C2H6 by modeling tropospheric absorption (similar to 200 mbar) and stratospheric emission (similar to 5 mbar) in the C2H2 V-5 and C2H6 v(9) bands, and also emission of the acetylene (v(4) + v(5)) - v(4) hotband (similar to 0.1 mbar). Acetylene shows a distinct north-south asymmetry in the stratosphere, with 5 mbar abundances greatest close to 20 degrees N and decreasing from there towards both poles by a factor of similar to 4. At 200 mbar in contrast, acetylene is nearly flat at a level of similar to 3 x 10(-9). Additionally, the abundance gradient Of C2H2 between 10 and 0.1 mbar is derived, based on interpolated temperatures at 0.1 mbar, and is found to be positive and uniform with latitude to within errors. Ethane at both 5 and 200 mbar shows increasing VMR towards polar regions of similar to 1.75 towards 70 degrees N and similar to 2.0 towards 70 degrees S. An explanation for the meridional trends is proposed in terms of a combination of photochemistry and dynamics. Poleward, the decreasing UV flux is predicted to decrease the abundances Of C2H2 and C2H6 by factors of 2.7 and 3.5, respectively, at latitude 70 degrees. However, the lifetime Of C2H6 in the stratosphere (3 x 10(10) s at 5 mbar) is much longer than the dynamical timescale for meridional mixing inferred from Comet SL-9 debris (5-50 x 10(8) s), and therefore the rising abundance towards high latitudes likely indicates that meridional mixing dominates over photochemical effects. For C2H2, the opposite occurs, with the relatively short photochemical lifetime Q x 10(7) s), compared to meridional mixing times, ensuring that the expected photochemical trends are visible. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Maryland, College Pk, MD 20742 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Univ Oxford, Clarendon Lab, Oxford OX1 3PU, England. LESIA, Observ Paris, F-92195 Meudon, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Huntsville, AL 35899 USA. Johns Hopkins Univ, Dept Earth & Planetary Sci, Baltimore, MD 21218 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Nixon, CA (reprint author), NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Planetary Syst Lab, Code 693, Greenbelt, MD 20771 USA. EM conor.nixon@gsfc.nasa.gov RI Nixon, Conor/A-8531-2009; Flasar, F Michael/C-8509-2012; Romani, Paul/D-2729-2012; Simon, Amy/C-8020-2012; Fouchet, Thierry/C-6374-2017; OI Nixon, Conor/0000-0001-9540-9121; Simon, Amy/0000-0003-4641-6186; Fouchet, Thierry/0000-0001-9040-8285; Teanby, Nicholas/0000-0003-3108-5775; Irwin, Patrick/0000-0002-6772-384X NR 76 TC 35 Z9 35 U1 1 U2 6 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2007 VL 188 IS 1 BP 47 EP 71 DI 10.1016/j.icarus.2006.11.016 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 160WA UT WOS:000245971900004 ER PT J AU Fletcher, LN Irwin, PGJ Teanby, NA Orton, GS Parrish, PD Calcutt, SB Bowles, N de Kok, R Howett, C Taylor, FW AF Fletcher, L. N. Irwin, P. G. J. Teanby, N. A. Orton, G. S. Parrish, P. D. Calcutt, S. B. Bowles, N. de Kok, R. Howett, C. Taylor, F. W. TI The meridional phosphine distribution in Saturn's upper troposphere from Cassini/CIRS observations SO ICARUS LA English DT Article DE Saturn; atmospheres, composition ID ROTOTRANSLATIONAL ABSORPTION-SPECTRA; VOYAGER INFRARED MEASUREMENTS; HUBBLE-SPACE-TELESCOPE; ISO-SWS OBSERVATIONS; CLOUD STRUCTURE; GIANT PLANETS; VERTICAL-DISTRIBUTION; THERMAL STRUCTURE; LINE PARAMETERS; OUTER PLANETS AB The Cassini Composite Infrared Spectrometer (CIRS) has been used to derive the vertical and meridional variation of temperature and phosphine (PH3) abundance in Saturn's upper troposphere. PH3 has a significant effect on the measured radiances in the thermal infrared and between May 2004 and September 2005 CIRS recorded thousands of spectra in both the far (10-600 cm(-1)) and mid (600-1400 cm(-1)) infrared, at a variety of latitudes covering the southern hemisphere. Low spectral resolution (15 cm(-1)) data has been used to constrain the temperature structure of the troposphere between 100 and 500 mbar. The vertical distributions of phosphine and ammonia were retrieved from far-infrared spectra at the highest spectral resolution (0.5 cm(-1)), and lower resolution (2.5 cm(-1)) mid-infrared data were used to map the meridional variation in the abundance of phosphine in the 250-500 mbar range. Temperature variations at the 250 mbar level are shown to occur on the same scale as the prograde and retrograde jets in Saturn's atmosphere [Porco, C.C., and 34 colleagues, 2005. Science 307, 1243-1247]. The PH3 abundance at 250 mbar is found to be enhanced at the equator when compared with mid-latitudes. At mid latitudes we see anti-correlation between temperature and PH3 abundance at 250 mbar, phosphine being enhanced at 45 degrees S and depleted at 25 and 55 degrees S. The vertical distribution is markedly different polewards of 60-65 degrees S, with depleted PH3 at 500 mbar but a slower decline in abundance with altitude when compared with the mid-latitudes. This variation is similar to the variations of cloud and aerosol parameters observed in the visible and near infrared, and may indicate the subsidence of tropospheric air at polar latitudes, coupled with a diminished sunlight penetration depth reducing the rate of PH3 photolysis in the polar region. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Oxford, Clarendon Lab, Dept Phys, Oxford OX1 3PU, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fletcher, LN (reprint author), Univ Oxford, Clarendon Lab, Dept Phys, Parks Rd, Oxford OX1 3PU, England. EM fletcher@atm.ox.ac.uk RI Fletcher, Leigh/D-6093-2011; OI Fletcher, Leigh/0000-0001-5834-9588; Calcutt, Simon/0000-0002-0102-3170; Teanby, Nicholas/0000-0003-3108-5775; Irwin, Patrick/0000-0002-6772-384X NR 68 TC 20 Z9 20 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2007 VL 188 IS 1 BP 72 EP 88 DI 10.1016/j.icarus.2006.10.029 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 160WA UT WOS:000245971900005 ER PT J AU Hedman, MM Burns, JA Showalter, MR Porco, CC Nicholson, PD Bosh, AS Tiscareno, MS Brown, RH Buratti, BJ Baines, KH Clark, R AF Hedman, Matthew M. Burns, Joseph A. Showalter, Mark R. Porco, Carolyn C. Nicholson, Philip D. Bosh, Amanda S. Tiscareno, Matthew S. Brown, Robert H. Buratti, Bonnie J. Baines, Kevin H. Clark, Roger TI Saturn's dynamic D ring SO ICARUS LA English DT Article DE planetary rings; Saturn, rings ID CASSINI IMAGING SCIENCE; VOYAGER OBSERVATIONS; F-RING; OCCULTATION; SYSTEM; SATELLITES; FIELD AB The Cassini spacecraft has provided the first clear images of the D ring since the Voyager missions. These observations show that the structure of the D ring has undergone significant changes over the last 25 years. The brightest of the three ringlets seen in the Voyager images (named D72), has transformed from a narrow, < 40-km wide ringlet to a much broader and more diffuse 250-km wide feature. In addition, its center of light has shifted inwards by over 200 km relative to other features in the D ring. Cassini also finds that the locations of other narrow features in the D ring and the structure of the diffuse material in the D ring differ from those measured by Voyager. Furthermore, Cassini has detected additional ringlets and structures in the D ring that were not observed by Voyager. These include a sheet of material just interior to the inner edge of the C ring that is only observable at phase angles below about 60 degrees. New photometric and spectroscopic data from the ISS (Imaging Science Subsystem) and VIMS (Visual and Infrared Mapping Spectrometer) instruments onboard Cassini show the D ring contains a variety of different particle populations with typical particle sizes ranging from 1 to 100 microns. High-resolution images reveal fine-scale structures in the D ring that appear to be variable in time and/or longitude. Particularly interesting is a remarkably regular, periodic structure with a wavelength of similar to 30 km extending between orbital radii of 73.200 and 74,000 km. A similar structure was previously observed in 1995 during the occultation of the star GSC5249-01240, at which time it had a wavelength of similar to 60 km. We interpret this structure as a periodic vertical corrugation in the D ring produced by differential nodal regression of an initially inclined ring. We speculate that this structure may have formed in response to an impact with a comet or meteoroid in early 1984. (c) 2006 Elsevier Inc. All rights reserved. C1 Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Cornell Univ, Dept Theoret & Appl Mech, Ithaca, NY 14853 USA. SETI Inst, Mountain View, CA 94043 USA. Space Sci Inst, CICLOPS, Boulder, CO 80301 USA. Boston Univ, Lowell Observ, Flagstaff, AZ 86001 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. JPL, Pasadena, CA 91109 USA. USGS, Denver, CO 80225 USA. RP Hedman, MM (reprint author), Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. EM mmhedman@astro.cornell.edu RI Tiscareno, Matthew/D-6963-2011 NR 30 TC 28 Z9 28 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2007 VL 188 IS 1 BP 89 EP 107 DI 10.1016/j.icarus.2006.11.017 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 160WA UT WOS:000245971900006 ER PT J AU Vinatier, S Bezard, B Fouchet, T Teanby, NA de Kok, R Irwin, PGJ Conrath, BJ Nixon, CA Romani, PN Flasar, EM Coustenis, A AF Vinatier, Sandrine Bezard, Bruno Fouchet, Thierry Teanby, Nick A. de Kok, Remco Irwin, Patrick G. J. Conrath, Barney J. Nixon, Conor A. Romani, Paul N. Flasar, E. Michael Coustenis, Athena TI Vertical abundance profiles of hydrocarbons in Titan's atmosphere at 15 degrees S and 80 degrees N retrieved from Cassini/CIRS spectra SO ICARUS LA English DT Article DE titan; abundances; atmosphere; infrared observations ID ROTOTRANSLATIONAL ABSORPTION-SPECTRA; VOYAGER INFRARED OBSERVATIONS; STRATOSPHERIC TEMPERATURE; HETERODYNE OBSERVATIONS; SPECTROSCOPIC DATABASE; LATITUDINAL VARIATIONS; HCN; PAIRS; MILLIMETER; HAZE AB Limb spectra recorded by the Composite InfraRed Spectrometer (CIRS) on Cassini provide information on abundance vertical profiles of C2H2, C2H4, C2H6, CH3C2H, C3H8, C4H2, C6H6 and HCN, along with the temperature profiles in Titan's atmosphere. We analyzed two sets of spectra, one at 15 degrees S (Tb flyby) and the other one at 80 degrees N (T3 flyby). The spectral range 600-1400 cm(-1), recorded at a resolution of 0.5 cm(-1), was used to determine molecular abundances and temperatures in the stratosphere in the altitude range 100-460 km for Tb and 170-495 km for T3. Both temperature profiles show a well defined stratopause, at around 310 km (0.07 mbar) and 183 K at 13 degrees S, and 380 km (0.01 mbar) with 207 K at 80 degrees N. Near the north pole, stratospheric temperatures are colder and mesospheric temperatures are warmer than near the equator. C2H2, C2H6, C3H8 and HCN display vertical mixing ratio profiles that increase with height at 15 degrees S and 80 degrees N, consistent with their formation in the upper atmosphere, diffusion downwards and condensation in the lower stratosphere, as expected from photochemical models. The CH3C2H and C4H2 mixing ratios also increase with height at 15 degrees S. But near the north pole, their profiles present an unexpected minimum around 300 km, observed for the first time thanks to the high vertical resolution of the CIRS limb data. C2H4 is the only molecule having a vertical abundance profile that decreases with height at 15 degrees S. At 800 N, it also displays a minimum of its mixing ratio around the 0.1-mbar level. For C6H6, an upper limit of 1.1 ppb (in the 0.3-10 mbar range) is derived at 15 degrees S, whereas a constant mixing ratio profile of 3(-1.5)(+3) pole. 1 5 ppb is inferred near the north At 15 degrees S, the vertical profile of HCN exhibits a steeper gradient than other molecules, which suggests that a sink for this molecule exists in the stratosphere, possibly due to haze formation. All molecules display a more or less pronounced enrichment towards the north pole, probably due, in part, to subsidence of air at the north (winter) pole that brings air enriched in photochemical compounds from the upper atmosphere to lower levels. (c) 2006 Elsevier Inc. All rights reserved. C1 LESIA, Observ Paris, F-92195 Meudon, France. Univ Oxford, Clarendon Lab, Dept Phys, Oxford OX1 3PU, England. Cornell Univ, CRSR, Ithaca, NY 14853 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Vinatier, S (reprint author), LESIA, Observ Paris, 5 Pl Jules Janssem, F-92195 Meudon, France. EM sandrine.vinatier@obspm.fr RI Nixon, Conor/A-8531-2009; Romani, Paul/D-2729-2012; Flasar, F Michael/C-8509-2012; Fouchet, Thierry/C-6374-2017 OI Nixon, Conor/0000-0001-9540-9121; Fouchet, Thierry/0000-0001-9040-8285 NR 49 TC 128 Z9 128 U1 2 U2 15 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2007 VL 188 IS 1 BP 120 EP 138 DI 10.1016/j.icarus.2006.10.031 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 160WA UT WOS:000245971900008 ER PT J AU Lowry, SC Weissman, PR AF Lowry, Stephen C. Weissman, Paul R. TI Rotation and color properties of the nucleus of Comet 2P/Encke SO ICARUS LA English DT Article DE comets, nucleus; photometry ID KUIPER-BELT; ENCKE AB We present results from CCD observations of Comet 2P/Encke acquired at Steward Observatory's 2.3 m Bok Telescope on Kitt Peak. The observations were carried out in October 2002 when the comet was near aphelion. Rotational lightcurves in B-, V-, and R-filters were acquired over two nights of observations, and analysed to study the physical and color properties of the nucleus. The average apparent R-filter magnitude across both nights corresponds to a mean effective radius of 3.95 +/- 10.06 km, and this value is similar to that found for the V- and B-filters. Taking the observed brightness range, we obtain a/b >= 1.44 +/- 0.06 for the semi-axial ratio of Encke's nucleus. Applying the axial ratio to the R-filter photometry gives nucleus semi-axes of [3.60 +/- 0.09] x [5.20 +/- 0.13] km, using the empirically-derived albedo and phase coefficient. No coma or tail was seen despite deep imaging of the comet, and flux limits from potential unresolved coma do not exceed a few percent of the total measured flux, for standard coma models. This is consistent with many other published data sets taken when the comet was near aphelion. Our data includes the first detailed time series multi-color measurements of a cometary nucleus, and significant color variations were seen on October 3, though not repeated on October 4. The average color indices across both nights are: (V - R) = 0.39 +/- 0.06 and (B - V) = 0.73 +/- 0.06 ((R) over bar= 19.76 +/- 0.03). We analysed the R-filter time-series photometry using the method of Harris et al. [Harris, A.W., Young, J.W., Bowell, E., Martin, LT, Millis, R.L., Poutanen, M., Scaltriti, F., Zappala, V., Schober, H.J., Debehogne, H., Zeigler, K.W., 1989. Icarus 77, 171-186] to constrain the rotation period of the comet's nucleus, and find that a period of similar to 11.45 h will satisfy the data, however the errors bars are large. We have successfully linked our data with the September 2002 data from Fernandez et al. [Fernandez, Y.R., Lowry, S.C., Weissman, P.R., Mueller, B.E.A., Samarasinha, N.H., Belton, M.J.S., Meech, K.J., 2005. Icarus 175, 194-214-taken just 2-3 weeks before the current data set-and we show that a rotation period of just over I I h works extremely well for the combined data set. The resulting best-fit period is 11.083 +/- 0.003 h, consistent with the Fernandez et al. value. (c) 2007 Elsevier Inc. All rights reserved. C1 Queens Univ Belfast, Astrophys Res Ctr, Sch Phys & Mat, Belfast BT7 1NN, Antrim, North Ireland. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lowry, SC (reprint author), Queens Univ Belfast, Astrophys Res Ctr, Sch Phys & Mat, Belfast BT7 1NN, Antrim, North Ireland. EM s.c.lowry@qub.ac.uk NR 21 TC 11 Z9 11 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2007 VL 188 IS 1 BP 212 EP 223 DI 10.1016/j.icarus.2006.11.014 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 160WA UT WOS:000245971900015 ER PT J AU Gibb, EL DiSanti, MA Magee-Sauer, K Dello Russo, N Bonev, BP Mumma, MJ AF Gibb, Erika L. DiSanti, Michael A. Magee-Sauer, Karen Dello Russo, Neil Bonev, Boncho P. Mumma, Michael J. TI The organic composition of C/2001 A2 (LINEAR) II. Search for heterogeneity within a comet nucleus SO ICARUS LA English DT Article DE comets, composition; infrared observations; spectroscopy ID O1 HALE-BOPP; DEEPLY EMBEDDED PROTOSTARS; C/1996 B2 HYAKUTAKE; OH PROMPT EMISSION; WATER PRODUCTION; CARBON-MONOXIDE; FORMALDEHYDE EMISSION; SOLAR-SYSTEM; KUIPER-BELT; OORT CLOUD AB The nucleus of Comet C/2001 A2 (LINEAR) split several times during its recent apparition, presenting an unusual opportunity to search for chemical differences in freshly exposed material. We conducted this search using NIRSPEC at the W.M. Keck Observatory on four dates in 2001: 9.5 and 10.5 July and 4.4 and 10.5 August. We detected the R0 and R1 lines of the v(3) vibrational band of CH4 near 3.3 mu m on all dates. The R2 line was detected on 4.4 and 10.5 August. When we compare production rates of CH4 to H2O, we find evidence of a significant enhancement in August relative to that found in July. H2CO was securely detected via its v(1) and v(5) bands on 9.5 July. On 10.5 July, H2CO emission was much weaker, and its mixing ratio had dropped by a factor of about four. The mixing ratios for other detected volatile species did not change significantly over the course of the observations. We discuss the implications of this evidence for chemical heterogeneity in the nucleus of Comet C/2001 A2. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Missouri, Dept Phys & Astron, St Louis, MO 63121 USA. NASA, Goddard Space Flight Ctr, Planetary Syst Lab, Solar Syst Explorat Div, Greenbelt, MD 20771 USA. Rowan Univ, Dept Chem & Phys, Glassboro, NJ 08028 USA. Johns Hopkins Univ, Appl Phys Lab, Space Dept, Planetary Explorat Grp, Laurel, MD 20723 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Greenbelt, MD 20771 USA. RP Gibb, EL (reprint author), Univ Missouri, Dept Phys & Astron, St Louis, MO 63121 USA. EM gibbe@umsl.edu RI mumma, michael/I-2764-2013; Magee-Sauer, Karen/K-6061-2015; Dello Russo, Neil/G-2727-2015 OI Magee-Sauer, Karen/0000-0002-4979-9875; Dello Russo, Neil/0000-0002-8379-7304 NR 51 TC 26 Z9 26 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2007 VL 188 IS 1 BP 224 EP 232 DI 10.1016/j.icarus.2006.11.009 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 160WA UT WOS:000245971900016 ER PT J AU Yanushkevich, SN Stoica, A Shmerko, VP AF Yanushkevich, Svetlana N. Stoica, Adrian Shmerko, Vlad P. TI Synthetic biometrics SO IEEE COMPUTATIONAL INTELLIGENCE MAGAZINE LA English DT Article ID FACIAL EXPRESSIONS C1 Univ Calgary, Calgary, AB T2N 1N4, Canada. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yanushkevich, SN (reprint author), Univ Calgary, Calgary, AB T2N 1N4, Canada. NR 42 TC 4 Z9 4 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1556-603X EI 1556-6048 J9 IEEE COMPUT INTELL M JI IEEE Comput. Intell. Mag. PD MAY PY 2007 VL 2 IS 2 BP 60 EP 69 DI 10.1109/MCI.2007.353421 PG 10 WC Computer Science, Artificial Intelligence SC Computer Science GA 169UF UT WOS:000246616600007 ER PT J AU Barnes, NP AF Barnes, Norman P. TI Solid-state lasers from an efficiency perspective SO IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS LA English DT Article DE diode-pumped solid state lasers; laser efficiency; laser modeling; solid state lasers ID HIGH-POWER CW; TM-YLF LASER; FIBER LASER; MU-M; ENERGY TRANSFER; PUMPED LASER; YAG; OPERATION; LUMINESCENCE; SINGLE AB Solid-state lasers have remained a vibrant area of research because several major innovations expanded their capability. Major innovations are presented with emphasis on the laser efficiency. A product of efficiencies approach is developed and applied to describe laser performance. Efficiency factors are presented in closed form where practical and energy transfer effects are included where needed. In turn, efficiency factors are used to estimate threshold and slope efficiency, allowing a facile estimate of performance. Spectroscopic, thermal, and mechanical data are provided for common solid state laser materials. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Barnes, NP (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM n.p.barnes@larc.nasa.gov NR 52 TC 28 Z9 29 U1 1 U2 13 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1077-260X J9 IEEE J SEL TOP QUANT JI IEEE J. Sel. Top. Quantum Electron. PD MAY-JUN PY 2007 VL 13 IS 3 BP 435 EP 447 DI 10.1109/JSTQE.2007.895280 PG 13 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 180TY UT WOS:000247390200002 ER PT J AU Afzal, RS Yu, AW Dallas, JL Melak, A Lukemire, AT Ramos-Izqueirdo, L Mamakos, W AF Afzal, Robert S. Yu, Anthony W. Dallas, Joseph L. Melak, Anthony Lukemire, Alan T. Ramos-Izqueirdo, L. Mamakos, William TI The geoscience laser altimeter system (GLAS) laser transmitter SO IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS LA English DT Article DE altimetry; laser radar; Q-switched lasers; YAG lasers ID ND-YAG LASER; MARS AB The Geoscience Laser Altimeter System (GLAS), launched in January 2003, is a laser altimeter and lidar for the Earth Observing System's (EOS) ICESat mission. GLAS accommodates three, sequentially operated, diode-pumped, solid-state, Nd:YAG laser transmitters. The laser transmitter requirements, design, and qualification test results for this space-based remotesensing instrument is summarized and presented. C1 Aculight Corp, Bothell, WA 98011 USA. NASA, Space Lidar Technol Ctr, College Pk, MD 20740 USA. RP Afzal, RS (reprint author), Aculight Corp, Bothell, WA 98011 USA. EM robert.afzal@aculight.com; anthony.w.yu@nasa.gov; jdallas@avophotonics.com; tony.melak@sigmaspace.com; alan@spacepower.com; ramos-izquierdo@nasa.gov; di@transsys.com NR 22 TC 36 Z9 42 U1 2 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1077-260X EI 1558-4542 J9 IEEE J SEL TOP QUANT JI IEEE J. Sel. Top. Quantum Electron. PD MAY-JUN PY 2007 VL 13 IS 3 BP 511 EP 536 DI 10.1109/JSTQE.2007.896051 PG 26 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 180TY UT WOS:000247390200010 ER PT J AU Prasad, NS Edwards, WC Trivedi, SB Kutcher, SW Wang, CC Kim, JS Hommerich, U Shukla, V Sadangi, R Kear, BH AF Prasad, Narasimha S. Edwards, William C. Trivedi, Sudhir B. Kutcher, Susan W. Wang, Chen-Chia Kim, Joo-Soo Hommerich, Uwe Shukla, Vijay Sadangi, Rajendra Kear, Bernard H. TI Recent progress in the development of neodymium-doped ceramic yttria SO IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS LA English DT Article DE ceramics; neodymium-doped yttria; remote sensing; solid-state lasers ID LASER; Y3AL5O12 AB Solid-state lasers play a significant role in providing the technology necessary for active remote sensing of the atmosphere. Neodymium-doped yttria (Nd:Y2O3) is considered to be an attractive material due to its possible lasing wavelengths of similar to 914 and similar to 946 min for ozone profiling. These wavelengths, when frequency tripled, can generate ultraviolet (UV) light at similar to 305 and similar to 315 nm, which is particularly useful for ozone sensing using differential absorption light detection and ranging (LIDAR) technique. For practical realization of space-based UV transmitter technology, ceramic Nd:Y2O3 material is considered to possess a great potential. A plasma melting and quenching method has been developed to produce Nd3+ -doped powders for consolidation into Nd:Y2O3 ceramic laser materials. This far-from-equilibrium processing methodology allows higher levels of rare earth doping than can be achieved by equilibrium methods. The method comprises two main steps: 1) plasma melting and quenching to generate dense, and homogeneous doped metastable powders and 2) pressure- assisted consolidation of these powders by hot isostatic pressing to make dense nanocomposite ceramics. Using this process, several 1 in x 1 in ceramic cylinders have been produced. The infrared transmission of a 2-mm-thick undoped Y2O3 ceramic was as high as -75% without antirellection coating. In the case of Nd:Y2O3, ceramics infrared transmission values of similar to 50% were achieved for a similar sample thickness. Furthermore, Nd:Y2O3 samples with dopant concentrations of up to similar to 2 at.% were prepared without significant emission quenching. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Brimrose Corp, Baltimore, MD 21152 USA. Hampton Univ, Dept Phys, Hampton, VA 23668 USA. Rutgers State Univ, Sch Engn, Ctr Nanomat Res, Piscataway, NJ 08854 USA. RP Prasad, NS (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM n.s.prasad@larc.nasa.gov; w.c.edwards@larc.nasa.gov; strivedi@brimrose.com; skutcher@brimrose.com; ccwang@brimrose.com; jkim@brimrose.com; uwe.hommerich@hamptonu.edu; vshukla@jove.rutgers.edu NR 20 TC 17 Z9 17 U1 1 U2 7 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1077-260X EI 1558-4542 J9 IEEE J SEL TOP QUANT JI IEEE J. Sel. Top. Quantum Electron. PD MAY-JUN PY 2007 VL 13 IS 3 BP 831 EP 837 DI 10.1109/JSTQE.2007.897179 PG 7 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 180TY UT WOS:000247390200042 ER PT J AU Deal, WR Mei, XB Radisic, V Yoshida, W Liu, PH Uyeda, J Barsky, M Gaier, T Fung, A Samoska, L Lai, R AF Deal, W. R. Mei, X. B. Radisic, V. Yoshida, W. Liu, P. H. Uyeda, J. Barsky, M. Gaier, T. Fung, A. Samoska, L. Lai, R. TI Demonstration of a 270-GHz MMIC amplifier using 35-nm, InPHEMT technology SO IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS LA English DT Article DE coplanar waveguide (CPW); high electron mobility transistor (HEMT); low noise amplifier (LNA); millimeterwave (MM-wave); MM-wave integrated circuit (MMIC); sub-MM-wave AB In this letter, the first 270-GHz millimeter-wave integrated circuit (MMIC) amplifier is demonstrated. Peak measured gain of 11.6-dB is measured for the three stage amplifier realized in coplanar waveguide. Further, positive S21 gain is measured to 340 GHz making this the highest frequency MMIC amplifier reported to date. The high frequency circuit performance is enabled through a 35-nm InP high electron mobility transistor capable of extremely high frequency operation. C1 Northrop Grumman Corp, Redondo Beach, CA 90278 USA. Jet Prop Lab, Pasadena, CA 91109 USA. RP Deal, WR (reprint author), Northrop Grumman Corp, Redondo Beach, CA 90278 USA. EM william.deal@ngst.com NR 9 TC 18 Z9 20 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1531-1309 J9 IEEE MICROW WIREL CO JI IEEE Microw. Wirel. Compon. Lett. PD MAY PY 2007 VL 17 IS 5 BP 391 EP 393 DI 10.1109/LMWC.2007.895728 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 166KU UT WOS:000246378400027 ER PT J AU Colozza, A AF Colozza, Anthony TI Fly like a bird SO IEEE SPECTRUM LA English DT Article C1 Analex Corp, Fairfax, VA USA. NASA, Glenn Res Ctr, Cleveland, OH USA. RP Colozza, A (reprint author), Analex Corp, Fairfax, VA USA. NR 2 TC 12 Z9 12 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9235 J9 IEEE SPECTRUM JI IEEE Spectr. PD MAY PY 2007 VL 44 IS 5 BP 38 EP 43 DI 10.1109/MSPEC.2007.352531 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA 166JG UT WOS:000246374400018 ER PT J AU Wilson, JD Chevalier, CT AF Wilson, Jeffrey D. Chevalier, Christine T. TI Robust optimization of high-frequency traveling-wave tube slow-wave circuits SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article DE algorithm; optimization; robust design; simulated annealing; traveling-wave tube (TWT) ID EFFICIENCY; POWER AB An optimization algorithm has been developed to provide robust designs for slow-wave circuits of high-frequency traveling-wave tubes (TWTs). The algorithm utilizes the optimization method of simulated annealing in a TWT simulation code. By considering the effects of dimensional variations during the optimization, a phase-velocity profile of a slow-wave circuit is generated. A simulated statistical performance test of a robust design for a 94-GHz folded-waveguide circuit shows significantly less sensitivity to dimensional tolerance variations. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Analex Corp, Cleveland, OH 44135 USA. RP Wilson, JD (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM Jeffrey.D.Wilson@nasa.gov NR 16 TC 4 Z9 4 U1 3 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD MAY PY 2007 VL 54 IS 5 BP 1232 EP 1237 DI 10.1109/TED.2007.894613 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 161RQ UT WOS:000246033700040 ER PT J AU Loughner, CP Lary, DJ Sparling, LC Cohen, RC DeCola, P Stockwell, WR AF Loughner, Christopher P. Lary, David J. Sparling, Lynn C. Cohen, Ronald C. DeCola, Phil Stockwell, W. R. TI A method to determine the spatial resolution required to observe air quality from space SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE air-quality observations; length scales; variograms ID UNITED-STATES; OZONE; TRANSPORT; SCALE; URBAN; NO2 AB Satellite observations have the potential to provide an accurate picture of atmospheric chemistry and air quality on a variety of spatial and temporal scales. A key consideration in the design of new instruments is the spatial resolution required to effectively monitor air quality from space. In this paper, variograms have been used to address this issue by calculating the horizontal length scales of ozone within the boundary layer and free troposphere using both in situ aircraft data from five different NASA aircraft campaigns and simulations with an air-quality model. For both the observations and the model, the smallest scale features were found in the boundary layer, with a characteristic scale of about 50 km which increased to greater than 150 km above the boundary layer. The length scale changes with altitude. It is shown that similar length scales are derived based on a totally independent approach using constituent lifetimes and typical wind speeds. To date, the spaceborne observations of tropospheric constituents have been from several instruments including TOMS, GOME, MOPITT, TES, and OMI which, in general, have different weighting functions that need to be considered, and none really measures at the surface. A further complication is that most satellite measurements (such as those of OMI and GOME) are of the vertically integrated column. In this paper, the length scales in the column measurements were also of the order of 50 km. To adequately resolve the 50-km features, a horizontal resolution of at least 10 km would be desirable. C1 Univ Maryland, Dept Atmospher & Ocean Sci, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Div Atmospher Chem, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, GEST, Baltimore, MD 21250 USA. Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA. Univ Calif Berkeley, Dept Chem, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Earth & Planetary Sci, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Berkeley Atmospher Sci Ctr, Berkeley, CA 94720 USA. Natl Aeronaut & Space Adm, Washington, DC USA. Howard Univ, Dept Chem, Washington, DC 20059 USA. RP Loughner, CP (reprint author), Univ Maryland, Dept Atmospher & Ocean Sci, College Pk, MD 20742 USA. EM David.Lary@umbc.edu RI Lary, David/A-6163-2010; Cohen, Ronald/A-8842-2011; OI Cohen, Ronald/0000-0001-6617-7691; Stockwell, William/0000-0002-7509-6575; Loughner, Christopher/0000-0002-3833-2014 NR 21 TC 11 Z9 11 U1 2 U2 9 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 2007 VL 45 IS 5 BP 1308 EP 1314 DI 10.1109/TGRS.2007.893732 PN 2 PG 7 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 161SE UT WOS:000246035300002 ER PT J AU Hong, G Yang, P Huang, HL Baum, BA Hu, YX Platnick, S AF Hong, Gang Yang, Ping Huang, Hung-Lung Baum, Bryan A. Hu, Yongxiang Platnick, Steven TI The sensitivity of ice cloud optical and microphysical passive satellite retrievals to cloud geometrical thickness SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE geometrical thickness; ice cloud; Moderate Resolution Imaging Spectroradiometer (MODIS); remote sensing ID OPERATIONAL VERTICAL SOUNDER; SOLAR-RADIATION MEASUREMENTS; AIRBORNE SIMULATOR IMAGERY; CIRRUS CLOUDS; THIN CIRRUS; BIDIRECTIONAL REFLECTANCE; THERMODYNAMIC PHASE; INFRARED RADIANCES; EFFECTIVE RADIUS; AVHRR CHANNELS AB Most satellite-based ice cloud retrieval algorithms rely on precomputed lookup libraries for inferring the ice cloud optical thickness (tau) and effective particle size (D-e). However, this retrieval methodology does not account for the case where cloud geometrical thickness may vary by several kilometers. In this paper, we investigate the effect of the ice cloud geometrical thickness on the retrieval of tau and D-e for algorithms using the Moderate Resolution Imaging Spectroradiometer infrared (IR) bands at 8.5 and 11 mu m (or 12 mu m) or solar bands at 0.65 and 1.64 mu m (or 2.13 mu m). We use a rigorous radiative transfer package to simulate the IR brightness temperatures and solar reflectances, assuming that the ice cloud top height is fixed at 12 or 15 km with a variation of cloud geometrical thickness from 0.5 to 5 km. The simulated brightness temperatures and reflectances are then used to investigate the errors of cloud tau and D-e inferred from the precomputed lookup tables developed with a specific geometrical thickness. It is found that the retrieval errors in tau and D-e increase with increasing tau for the IR and solar methods. In both cases, cloud tau and D-e mail be underestimated and overestimated, respectively, if the effect of the cloud geometrical thickness is not taken into account. The effect of the cloud geometrical thickness on the retrieval of cloud optical and microphysical properties is much larger for the IR algorithm than for the solar-band-based algorithm. This paper demonstrates that the inclusion of the information about the cloud geometrical thickness may improve the accuracy of the retrieval of the cloud properties on the basis of the precomputed lookup libraries. C1 Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. Univ Wisconsin, Ctr Space Sci & Engn, Madison, WI 53706 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. NASA, Goddard Space Flight Ctr, Div Earth Sci, Greenbelt, MD 20771 USA. RP Hong, G (reprint author), Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. EM pyang@ariel.met.tamu.edu RI Yang, Ping/B-4590-2011; Baum, Bryan/B-7670-2011; Hong, Gang/A-2323-2012; Platnick, Steven/J-9982-2014; Hu, Yongxiang/K-4426-2012 OI Baum, Bryan/0000-0002-7193-2767; Platnick, Steven/0000-0003-3964-3567; NR 47 TC 15 Z9 15 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 2007 VL 45 IS 5 BP 1315 EP 1323 DI 10.1109/TGRS.2007.894549 PN 2 PG 9 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 161SE UT WOS:000246035300003 ER PT J AU Jin, KW Hong, SW Weitz, R Wilheit, T AF Jin, Kyoung-Wook Hong, Sung-Wook Weitz, Richard Wilheit, Thomas TI Improved physically based oceanic rainfall algorithm from AMSR-E data SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE advanced microwave scanning radiometer for Earth Observing System (AMSR-E) (EOS); microwave remote sensing; precipitation; rainfall ID MICROWAVE; PRECIPITATION; SATELLITE AB An improved oceanic rainfall algorithm based on a radiative transfer model that reduces many uncertainties of rainfall retrieval was developed using advanced microwave scanning radiometer for Earth Observing System data. Error models were embedded to quantify rainfall uncertainties and to reduce net uncertainties. Six channels (37, 18, and 10 GHz with dual polarization) were utilized in the algorithm. Several developments such as improvement of the freezing-level (FL) retrieval, a weighted average scheme, and enhanced offset correction were implemented in this paper. As a result, rain rate uncertainties were substantially reduced and quantified. To establish error models, drop-size-distribution uncertainty, beam filling error, data calibration uncertainty, and instrument noise were taken into account. These error models were used to compute proper weights of each channel to combine the six rain rates. The algorithm was evaluated with respect to the current operational algorithm (NASA Level 3 rainfall algorithm). It showed more reasonable mean FLs and rain rate estimation than the operational algorithm. Furthermore, pixel-by-pixel-based quantitative error estimates were conducted through the error model. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NOAA, Natl Environm Satellite Data & Informat Serv, Suitland, MD 20746 USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. RP Jin, KW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM kwjin@jpl.nasa.gov RI Wilheit, Thomas/G-9438-2012 NR 16 TC 3 Z9 3 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 2007 VL 45 IS 5 BP 1332 EP 1341 DI 10.1109/TGRS.2007.894931 PN 2 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 161SE UT WOS:000246035300005 ER PT J AU Chan, T Liu, CC Howe, BM Kirkham, H AF Chan, Ting Liu, Chen-Ching Howe, Bruce M. Kirkham, Harold TI Fault location for the NEPTUNE power system SO IEEE TRANSACTIONS ON POWER SYSTEMS LA English DT Article DE current measurement; DC power systems; fault location; underwater technology; voltage measurement AB The objective of the North Eastern Pacific Time-Series Undersea Networked Experiment (NEPTUNE) program is to construct an underwater cabled observatory on the floor of the Pacific Ocean, encompassing the Juan de Fuca Tectonic Plate. The power system associated with the proposed observatory is unlike conventional terrestrial power systems in many ways due to the unique operating conditions of underwater cabled observatories. In the event of a backbone cable fault, the location of the fault must be identified accurately so that a repair ship can be sent to repair the cable. Due to the proposed networked, mesh structure, traditional techniques for cable fault identification can not achieve the desired level of accuracy. In this paper, a system-theoretic method is proposed for identification of the fault location based on the limited data available. The method has been tested with extensive simulations and is being implemented for the field test in Monterey, California. In this study, a lab test is performed for the fault location function. C1 Univ Washington, Dept Elect Engn, Seattle, WA 98195 USA. Iowa State Univ, Dept Elect & Comp Engn, Ames, IA 50011 USA. Univ Washington, Appl Phys Lab, Seattle, WA 98195 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chan, T (reprint author), Univ Washington, Dept Elect Engn, Seattle, WA 98195 USA. EM tingc@u.washington.edu; liu@iastate.edu; howe@apl.washington.edu; Harold.Kirkham@jpl.nasa.gov RI Howe, Bruce/J-2807-2012; OI Howe, Bruce/0000-0001-5711-5253; Kirkham, Harold/0000-0003-2893-7586 NR 21 TC 1 Z9 6 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0885-8950 J9 IEEE T POWER SYST JI IEEE Trans. Power Syst. PD MAY PY 2007 VL 22 IS 2 BP 522 EP 531 DI 10.1109/TPWRS.2007.894855 PG 10 WC Engineering, Electrical & Electronic SC Engineering GA 164YO UT WOS:000246271100003 ER PT J AU Narasimhan, S Biswas, G AF Narasimhan, Sriram Biswas, Gautam TI Model-based diagnosis of hybrid systems SO IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART A-SYSTEMS AND HUMANS LA English DT Article DE fault detection and isolation; hybrid systems; model-based diagnosis (MBD) ID IDENTIFICATION AB Techniques for diagnosing faults in hybrid systems that combine digital (discrete) supervisory controllers with analog (continuous) plants need to be different from those used for discrete or continuous systems. This paper presents a methodology for online tracking and diagnosis of hybrid systems. We demonstrate the effectiveness of the approach with experiments conducted on the fuel-transfer system of fighter aircraft. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Vanderbilt Univ, Dept Elect Engn & Comp Sci, Nashville, TN 37235 USA. Vanderbilt Univ, Inst Software Integrated Syst, Nashville, TN 37235 USA. RP Narasimhan, S (reprint author), Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. EM sriram@e-mail.arc.nasa.gov; gautam.biswas@vanderbilt.edu NR 27 TC 92 Z9 99 U1 1 U2 9 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1083-4427 J9 IEEE T SYST MAN CY A JI IEEE Trans. Syst. Man Cybern. Paart A-Syst. Hum. PD MAY PY 2007 VL 37 IS 3 BP 348 EP 361 DI 10.1109/TSMCA.2007.893487 PG 14 WC Computer Science, Cybernetics; Computer Science, Theory & Methods SC Computer Science GA 161RX UT WOS:000246034500007 ER PT J AU Young, SD Adelstein, BD Ellis, SR AF Young, Sean D. Adelstein, Bernard D. Ellis, Stephen R. TI Demand characteristics in assessing motion sickness in a virtual environment: Or does taking a motion sickness questionnaire make you sick? SO IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS LA English DT Article; Proceedings Paper CT IEEE Virtual Reality 2006 Conference CY MAR 25-29, 2006 CL Alexandria, VA SP IEEE Comp Soc, IEEE VGTC DE motion sickness; cyber sickness; demand characteristics; user study; manual control; three; dimensional tracking; placebo effect; virtual environment ID PSYCHOLOGICAL EXPERIMENT; SOCIAL-PSYCHOLOGY; PLACEBO; DETERMINANT AB The experience of motion sickness in a virtual environment may be measured through pre and postexperiment self-reported questionnaires such as the Simulator Sickness Questionnaire (SSQ). Although research provides converging evidence that users of virtual environments can experience motion sickness, there have been no controlled studies to determine to what extent the user's subjective response is a demand characteristic resulting from pre and posttest measures. In this study, subjects were given either SSQ's both pre and postvirtual environment immersion, or only postimmersion. This technique tested for contrast effects due to demand characteristics in which administration of the questionnaire itself suggested to the participant that the virtual environment may produce motion sickness. Results indicate that reports of motion sickness after immersion in a virtual environment are much greater when both pre and postquestionnaires are given than when only a posttest questionnaire is used. The implications for assessments of motion sickness in virtual environments are discussed. C1 Stanford Univ, Dept Psychol, Stanford, CA 94305 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Young, SD (reprint author), Stanford Univ, Dept Psychol, Jordan Hall, Stanford, CA 94305 USA. EM young@psych.stanford.edu; Bernard.D.Adelstein@nasa.gov; sellis@mail.arc.nasa.gov NR 41 TC 21 Z9 21 U1 1 U2 13 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1077-2626 J9 IEEE T VIS COMPUT GR JI IEEE Trans. Vis. Comput. Graph. PD MAY-JUN PY 2007 VL 13 IS 3 BP 422 EP 428 DI 10.1109/TVCG.2007.1029 PG 7 WC Computer Science, Software Engineering SC Computer Science GA 145WA UT WOS:000244895300002 PM 17356210 ER PT J AU Amador, JJ AF Amador, Jose J. TI Random projection and orthonormality for lossy image compression SO IMAGE AND VISION COMPUTING LA English DT Article DE image compression; random projection; transform image coding ID DISCRETE HARTLEY TRANSFORM; COSINE TRANSFORM; SINE AB There exist many lossy image compression techniques, some of which are based on dimensionality reduction. In this paper, a method for lossy image compression is introduced which utilizes the dimensionality reduction technique known as Random Projection. Random Projection has proven itself as an effective technique for reducing the dimensionality of data, particularly when dimensionality d is moderately high (e.g., d < 1500). Image columns or rows are treated as vectors in feature space which are thereby reduced in size to a user specified dimension k where k < d. The condition of orthonormality is utilized thereby establishing a technique applicable to image compression. Although the compression is lossy, experiments indicate that the recovered image is effectively restored. Visual data is shown in the form of comparison between original and recovered image. Quantitative data includes the compression ratio achieved, the peak signal-to-noise ratio, and the root mean square error. Published by Elsevier B.V. C1 NASA, John F Kennedy Space Ctr, Kennedy Space Ctr, FL 32899 USA. RP Amador, JJ (reprint author), NASA, John F Kennedy Space Ctr, Kennedy Space Ctr, FL 32899 USA. EM Jose.J.Amador@nasa.gov NR 40 TC 5 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0262-8856 EI 1872-8138 J9 IMAGE VISION COMPUT JI Image Vis. Comput. PD MAY 1 PY 2007 VL 25 IS 5 BP 754 EP 766 DI 10.1016/j.imavis.2006.05.018 PG 13 WC Computer Science, Artificial Intelligence; Computer Science, Software Engineering; Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA 149SF UT WOS:000245166200020 ER PT J AU Ludovisi, D Cha, SS Ramachandran, N Worek, WM AF Ludovisi, D. Cha, S. S. Ramachandran, N. Worek, W. M. TI Effect of magnetic field on two-layered natural/thermocapillary convection SO INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER LA English DT Article; Proceedings Paper CT 13th International Heat Transfer Conference CY AUG 13-18, 2006 CL Sydney, AUSTRALIA DE Marangoni flow; thermocapillary flow; interfacial tension; magnetic field; two-layered fluid system ID IMMISCIBLE LIQUID LAYERS; HORIZONTAL TEMPERATURE-GRADIENT; THERMOCAPILLARY CONVECTION; NATURAL-CONVECTION; MARANGONI CONVECTION; FREE-SURFACE; FLUID; CAVITY; BUOYANCY; FLOW AB Heat transfer in a two-layered fluid system is of great importance in a variety of applications. Control and optimization of convective heat transfer of the immiscible fluids needs complete understanding of all phenomena, especially those induced by surface tension at the fluid interface. The present work is focused on rather complex convective flow and heat transfer phenomena in a cavity, which can be subject to both buoyancy and thermocapillary effects in addition to the influence of magnetic field applied for flow control. With the encapsulant liquid posing magnetic properties, a magnetic force can arise to either enhance or counterbalance the gravity effect when the cavity is placed in a non-uniform magnetic field. In our study, the velocity and temperature distribution of the system can be significantly altered to change the heat transfer by varying intensity and gradient of the applied magnetic field. Preliminary results of numerical computation presented here are for a two-layered liquid cavity MnCl(2 center dot)4H(2)O and Fluorinert FC40 under various magnetic fields intensities. (C) 2007 Published by Elsevier Ltd. C1 Univ Illinois, Dept Mech & Ind Engn, Chicago, IL 60607 USA. NASA, George C Marshall Space Flight Ctr, Jacobs ESTS Grp, Huntsville, AL 35812 USA. RP Cha, SS (reprint author), Univ Illinois, Dept Mech & Ind Engn, 842 W Taylor St,Room 2039 ERF M-C 251, Chicago, IL 60607 USA. EM sscha@uic.edu NR 23 TC 4 Z9 4 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0735-1933 J9 INT COMMUN HEAT MASS JI Int. Commun. Heat Mass Transf. PD MAY PY 2007 VL 34 IS 5 BP 523 EP 533 DI 10.1016/j.icheatmasstransfer.2007.02.003 PG 11 WC Thermodynamics; Mechanics SC Thermodynamics; Mechanics GA 174KL UT WOS:000246940700002 ER PT J AU Faircloth, DL Baginski, ME Rao, SM Wentworth, SM Deshpande, MD AF Faircloth, Daniel L. Baginski, Michael E. Rao, Sadasiva M. Wentworth, Stuart M. Deshpande, Manohar D. TI Modified genetic algorithm to design arbitrary response filters for rectangular waveguides SO INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING LA English DT Article DE waveguide filter; genetic algorithm; finite element method; geometry-refinement technique ID OPTIMIZATION; ELECTROMAGNETICS; DEVICES AB In this study, we present an improved genetic algorithm (GA) to design user-specified filters housed in a waveguide of arbitrary cross-sectional dimensions. An edge-based finite element method (FEM) is employed as the forward solver for the problem. Additionally, the structures generated via the GA are easily constructed using standard printed circuit board fabrication techniques. Two of the major improvements to the GA are: (1) a technique for enhancing the GA's ability to avoid local minima and (2) a fine-tuning mechanism which allows the GA to more efficiently seek out a minimum once a low error has been obtained. Using the aforementioned techniques, numerical/experimental results are presented for notch, low pass, high pass, and bandpass filters. (C) 2007 Wiley Periodicals, Inc. C1 Dynet Inc, EM Predict & Measurements Sect, Huntsville, AL 35814 USA. Auburn Univ, Dept Elect & Comp Engn, Auburn, AL 36849 USA. NASA, Goddard Space Flight Ctr, Microwave Instrumentat & Technol Branch, Greenbelt, MD 20771 USA. RP Faircloth, DL (reprint author), Dynet Inc, EM Predict & Measurements Sect, Huntsville, AL 35814 USA. EM daniel.faircloth@dynetics.com NR 22 TC 0 Z9 0 U1 0 U2 1 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 1096-4290 J9 INT J RF MICROW C E JI Int. J. RF Microw. Comput-Aid. Eng. PD MAY PY 2007 VL 17 IS 3 BP 367 EP 375 DI 10.1002/mmce.20246 PG 9 WC Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 165ZA UT WOS:000246345200015 ER PT J AU Basu, S Waas, AM Ambur, DR AF Basu, Shiladitya Waas, Anthony M. Ambur, Damodar R. TI Prediction of progressive failure in multidirectional composite laminated panels SO INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES LA English DT Article ID FIBER COMPOSITES; COMPRESSIVE STRENGTH; KINK BANDS; DAMAGE; BEHAVIOR AB A mechanism-based progressive failure analyses (PFA) approach is developed for fiber reinforced composite laminates. Each ply of the laminate is modeled as a nonlinear elastic degrading lamina in a state of plane stress according to Schapery theory (ST). In this theory, each lamina degrades as characterized through laboratory scale experiments. In the fiber direction, elastic behavior prevails, however, in the present work, the phenomenon of fiber microbuckling, which is responsible for the sudden degradation of the axial lamina properties under compression, is explicitly accounted for by allowing the fiber rotation at a material point to be a variable in the problem. The latter is motivated by experimental and numerical simulations that show that local fiber rotations in conjunction with a continuously degrading matrix are responsible for the onset of fiber microbuckling leading to kink banding. These features are built into a user defined material subroutine that is implemented through the commercial finite element (FE) software ABAQUS in conjunction with classical lamination theory (CLT) that considers a laminate as a collection of perfectly bonded lamina (Herakovich, C.T., 1998. Mechanics of Fibrous Composites. Wiley, New York). The present model, thus, disbands the notion of a fixed compressive strength, and instead uses the mechanics of the failure process to provide the in situ compression strength of a material point in a lamina, the latter being dictated strongly by the current local stress state, the current state of the lamina transverse material properties and the local fiber rotation. The inputs to the present work are laboratory scale, coupon level test data that provide information on the lamina transverse property degradation (i.e. appropriate, measured, strain-stress relations of the lamina transverse properties), the elastic lamina orthotropic properties, the ultimate tensile strength of the lamina in the fiber direction, the stacking sequence of the laminate and the geometry of the structural panel. The validity of the approach advocated is demonstrated through numerical simulations of the response of two composite structural panels that are loaded to complete failure. A flat, 24-ply unstiffened panel with a cutout subjected to in-plane shear loading, and a double notched 70-ply unstiffened stitched panel subjected to axial compression are selected for study. The predictions of the simulations are compared against experimental data. Good agreement between the present PFA and the experimental data are reported. (c) 2006 Elsevier Ltd. All rights reserved. C1 Univ Michigan, Dept Aerosp Engn, Composite Struct Lab, Ann Arbor, MI 48109 USA. Granherne Inc, Tech Profess Marine, Houston, TX 77002 USA. NASA, Glenn Res Ctr, Struct Div, Cleveland, OH 44135 USA. RP Waas, AM (reprint author), Univ Michigan, Dept Aerosp Engn, Composite Struct Lab, Ann Arbor, MI 48109 USA. EM dcw@umich.edu NR 29 TC 37 Z9 38 U1 3 U2 24 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7683 J9 INT J SOLIDS STRUCT JI Int. J. Solids Struct. PD MAY 1 PY 2007 VL 44 IS 9 BP 2648 EP 2676 DI 10.1016/j.ijsolstr.2006.08.010 PG 29 WC Mechanics SC Mechanics GA 158CU UT WOS:000245769500003 ER PT J AU Patnaik, SN Hopkins, DA AF Patnaik, Surya N. Hopkins, Dale A. TI Completed Beltrami-Michell formulation in polar coordinates SO INTERNATIONAL JOURNAL OF THE PHYSICAL SCIENCES LA English DT Article DE Elasticity; Boundary; Compatibility; Variational; Derivation ID INTEGRATED FORCE METHOD; CONTINUUM AB A set of conditions had not been formulated on the boundary of an elastic continuum since the time of Saint-Venant. This limitation prevented the formulation of a direct stress calculation method in elasticity for a continuum with a displacement boundary condition. The missed condition, referred to as the boundary compatibility condition, is now formulated in polar coordinates. The augmentation of the new condition completes the Beltrami-Michell formulation in polar coordinates. The completed formulation that includes equilibrium equations and a compatibility condition in the field as well as the traction and boundary compatibility condition is derived from the stationary condition of the variation functional of the integrated force method. The new method is illustrated by solving an example of a mixed boundary value problem for mechanical as well as thermal loads. C1 [Patnaik, Surya N.] Ohio Aerosp Inst, Brookpark, OH 44142 USA. [Hopkins, Dale A.] NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Patnaik, SN (reprint author), 22800 Cedar Point Rd, Cleveland, OH USA. EM surya.n.patnaik@nasa.gov NR 17 TC 0 Z9 0 U1 0 U2 1 PU ACADEMIC JOURNALS PI VICTORIA ISLAND PA P O BOX 5170-00200 NAIROBI, VICTORIA ISLAND, LAGOS 73023, NIGERIA SN 1992-1950 J9 INT J PHYS SCI JI Int. J. Phys. Sci. PD MAY PY 2007 VL 2 IS 5 BP 128 EP 139 PG 12 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 367WF UT WOS:000260582600003 ER PT J AU Yeomans, D AF Yeomans, Donald TI Is Pluto a planet? A historical journey through the solar system. SO JOURNAL FOR THE HISTORY OF ASTRONOMY LA English DT Book Review C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yeomans, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 0 Z9 0 U1 1 U2 2 PU SCIENCE HISTORY PUBLICATIONS LTD PI CAMBRIDGE PA 16 RUTHERFORD RD, CAMBRIDGE CB2 2HH, ENGLAND SN 0021-8286 J9 J HIST ASTRON JI J. Hist. Astron. PD MAY PY 2007 VL 38 BP 250 EP 251 PN 2 PG 2 WC History & Philosophy Of Science SC History & Philosophy of Science GA 170KC UT WOS:000246661300016 ER PT J AU Vargas, M Broughton, H Sims, JJ Bleeze, B Gaines, V AF Vargas, Mario Broughton, Howard Sims, James J. Bleeze, Brian Gaines, Vatanna TI Local and total density measurements in ice shapes SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 43rd Aerospace Sciences Meeting and Exhibit CY JAN 10-13, 2005 CL Reno, NV SP AIAA AB Preliminary measurements of local and total densities inside ice shapes were obtained from ice shapes grown in the NASA John H. Glenn. Icing Research Tunnel for a range of glaze ice, rime ice, and mixed-phase ice conditions on a NACA 0012 airfoil at 0-deg angle of attack. Prodi's x-ray contact microradiography method was extended using modern imaging techniques to conduct the measurements. The ice shapes were removed from the airfoil and a slice of ice 3-mm thick was obtained using a microtome. The resulting samples were then x-rayed to obtain a microradiograph, the film was digitized, and image processing techniques were used to extract the local and total density values. C1 NASA, Glenn Res Ctr, Icing Branch, Cleveland, OH 44135 USA. Pace Levy Inc, Westlake, OH 44145 USA. Universal Imaging Corp, Downingtown, PA 19335 USA. ISPA Technol Inc, Alexandria, VA 22314 USA. Lockheed Martin Aeronaut Co, Marietta, GA 30063 USA. RP Vargas, M (reprint author), NASA, Glenn Res Ctr, Icing Branch, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 10 TC 2 Z9 2 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2007 VL 44 IS 3 BP 780 EP 789 DI 10.2514/1.23326 PG 10 WC Engineering, Aerospace SC Engineering GA 180AH UT WOS:000247331700010 ER PT J AU Kim, MJ Kulie, MS O'Dell, C Bennartz, R AF Kim, Min-Jeong Kulie, Mark S. O'Dell, Chris Bennartz, Ralf TI Scattering of ice particles at microwave frequencies: A physically based parameterization SO JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY LA English DT Article ID DISCRETE-DIPOLE APPROXIMATION; OCEAN RAIN RATE; SIZE DISTRIBUTIONS; SOUNDING UNIT; AMSU-B; CLOUDS; PRECIPITATION; ALGORITHM; RADAR; AGGREGATION AB This paper presents a new, purely physical approach to simulate ice-particle scattering at microwave frequencies. Temperature-dependent ice particle size distributions measured by aircraft in midlatitude frontal systems are used to represent the distribution of precipitation-sized frozen hydrometeors above the freezing level through derived radar reflectivity-snow water content (Z-M) relationships. The discrete dipole approximation is employed to calculate optical properties of selected types of idealized nonspherical ice particles (hexagonal columns, four-arm rosettes, and six-arm rosettes). Based on those assumptions, passive microwave optical properties are calculated using radar observations from Gotland Island in the Baltic Sea. These forward-simulated brightness temperatures are compared with observed data from both the Advanced Microwave Scanning Radiometer (AMSR-E) and the Advanced Microwave Sounding Unit-B (AMSU-B). Results show that the new ice scattering/microphysics model is able to generate brightness temperatures that are consistent with AMSR and AMSU-B observations of two light-winter-precipitation cases. The overall differences among the various ice-habit results at 89 GHz are generally not that expansive, whereas the AMSU-B 150-GHz comparisons show increased sensitivity to ice-particle shapes. C1 Univ Wisconsin, Dept Atmospher & Ocean Sci, Madison, WI 53706 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RP Kim, MJ (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 614-6, Greenbelt, MD 20771 USA. EM min-jeong.kim@noaa.gov RI Kulie, Mark/C-3289-2011; Bennartz, Ralf/F-3760-2010 OI Kulie, Mark/0000-0003-1400-1007; NR 39 TC 16 Z9 16 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1558-8424 J9 J APPL METEOROL CLIM JI J. Appl. Meteorol. Climatol. PD MAY PY 2007 VL 46 IS 5 BP 615 EP 633 DI 10.1175/JAM2483.1 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 170ZT UT WOS:000246705400005 ER PT J AU Soibel, A Mansour, K Qiu, YM Hill, CJ Yang, RQ AF Soibel, Alex Mansour, Kamjou Qiu, Yueming Hill, Cory J. Yang, Rui Q. TI Optical gain, loss, and transparency current in high performance mid-infrared interband cascade lasers SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB The net modal gain, optical loss, and transparency current of high-performance, narrow ridge waveguide interband cascade (IC) lasers have been measured using the Hakki-Paoli technique in the temperature range from T=78 to 270 K. In this temperature range, the optical loss of IC lasers increases from alpha(w)approximate to 17 cm(-1) at T=78 K to alpha(w)approximate to 35 at T=270 K, the transparency current density rises from I-tr=10 to 330 A/cm(2), and the differential gain decreases from g(d)approximate to 2.2 cm/A to g(d)approximate to 0.06 cm/A with a characteristic temperature of T-0=130 K. The implications of these observed characteristics for IC lasers are discussed. (C) 2007 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Soibel, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM alexander.soibel@jpl.nasa.gov RI Soibel, Alexander/A-1313-2007 NR 14 TC 17 Z9 18 U1 0 U2 5 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 2007 VL 101 IS 9 AR 093104 DI 10.1063/1.2723188 PG 4 WC Physics, Applied SC Physics GA 169BO UT WOS:000246567900004 ER PT J AU Meneghini, R Liao, L AF Meneghini, Robert Liao, Liang TI On the equivalence of dual-wavelength and dual-polarization equations for estimation of the raindrop size distribution SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID POLARIMETRIC RADAR MEASUREMENTS; SPACEBORNE RADAR; PROFILING ALGORITHM; SINGLE-FREQUENCY; ATTENUATION; RAINFALL; CONSTRAINT; SHAPE AB For air- and spaceborne weather radars, which typically operate at frequencies of 10 GHz and above, attenuation correction is usually an essential part of any rain estimation procedure. For ground-based radars, where the maximum range within the precipitation is usually much greater than that from air- or spaceborne radars, attenuation correction becomes increasingly important at frequencies above about 5 GHz. Although dual-polarization radar algorithms rely on the correlation between raindrop shape and size, while dual-wavelength weather radar algorithms rely primarily on non-Rayleigh scattering at the shorter wavelength, the equations for estimating parameters of the drop size distribution (DSD) are nearly identical in the presence of attenuation. Many of the attenuation correction methods that have been proposed can be classified as one of two types: those that employ a kZ (specific attenuation-radar reflectivity factor) relation, and those that use an integral equation formalism where the attenuation is obtained from the DSD parameters at prior gates, either stepping outward from the radar or inward toward the radar from some final range gate. The similarity is shown between the dual-polarization and dual-wavelength equations when either the kZ or the integral equation formulation is used. Differences between the two attenuation correction procedures are illustrated for simulated measurements from an X-band dual-polarization radar. C1 NASA, Goddard Space Flight Ctr, Instrumentat Sci Branch, Greenbelt, MD 20771 USA. Caelum Res Corp, Goddard Earth Sci & Technol Ctr, Rockville, MD USA. RP Meneghini, R (reprint author), NASA, Goddard Space Flight Ctr, Instrumentat Sci Branch, Code 614-6, Greenbelt, MD 20771 USA. EM bob@neptune.gsfc.nasa.gov NR 27 TC 12 Z9 13 U1 1 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 EI 1520-0426 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD MAY PY 2007 VL 24 IS 5 BP 806 EP 820 DI 10.1175/JTECH2005.1 PG 15 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 169VR UT WOS:000246620700006 ER PT J AU Lee, MI Schubert, SD Suarez, MJ Held, IM Kumar, A Bell, TL Schemm, JKE Lau, NC Ploshay, JJ Kim, HK Yoo, SH AF Lee, Myong-In Schubert, Siegfried D. Suarez, Max J. Held, Isaac M. Kumar, Arun Bell, Thomas L. Schemm, Jae-Kyung E. Lau, Ngar-Cheung Ploshay, Jeffrey J. Kim, Hyun-Kyung Yoo, Soo-Hyun TI Sensitivity to horizontal resolution in the AGCM simulations of warm season diurnal cycle of precipitation over the United States and northern Mexico SO JOURNAL OF CLIMATE LA English DT Article ID GENERAL-CIRCULATION MODEL; LOW-LEVEL JET; GREAT-PLAINS; CLIMATE MODEL; SEMIDIURNAL VARIATIONS; GLOBAL PRECIPITATION; MOISTURE TRANSPORT; HYDROLOGIC-CYCLE; VARIABILITY; CONVECTION AB This study examines the sensitivity of the North American warm season diurnal cycle of precipitation to changes in horizontal resolution in three atmospheric general circulation models, with a primary focus on how the parameterized moist processes respond to improved resolution of topography and associated local/regional circulations on the diurnal time scale. It is found that increasing resolution (from approximately 2 degrees to 1/2 degrees in latitude-longitude) has a mixed impact on the simulated diurnal cycle of precipitation. Higher resolution generally improves the initiation and downslope propagation of moist convection over the Rockies and the adjacent Great Plains. The propagating signals, however, do not extend beyond the slope region, thereby likely contributing to a dry bias in the Great Plains. Similar improvements in the propagating signals are also found in the diurnal cycle over the North American monsoon region as the models begin to resolve the Gulf of California and the surrounding steep terrain. In general, the phase of the diurnal cycle of precipitation improves with increasing resolution, though not always monotonically. Nevertheless, large errors in both the phase and amplitude of the diurnal cycle in precipitation remain even at the highest resolution considered here. These errors tend to be associated with unrealistically strong coupling of the convection to the surface heating and suggest that improved simulations of the diurnal cycle of precipitation require further improvements in the parameterizations of moist convection processes. C1 NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ USA. NCEP, Climate Predict Ctr, Camp Springs, MD USA. RS Informat Syst Inc, Mclean, VA USA. RP Lee, MI (reprint author), NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Code 610-1, Greenbelt, MD 20771 USA. EM milee@gmao.gsfc.nasa.gov RI Bell, Thomas/G-5425-2012; OI Lee, Myong-In/0000-0001-8983-8624 NR 47 TC 55 Z9 55 U1 1 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAY PY 2007 VL 20 IS 9 BP 1862 EP 1881 DI 10.1175/JCL14090.1 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 167TE UT WOS:000246473800016 ER PT J AU Liu, JP Zhang, ZH Horton, RM Wang, CY Ren, XB AF Liu, Jiping Zhang, Zhanhai Horton, Radley M. Wang, Chunyi Ren, Xiaobo TI Variability of North Pacific sea ice and east Asia-North Pacific winter climate SO JOURNAL OF CLIMATE LA English DT Article ID ATMOSPHERIC CIRCULATION; MONSOON; TRENDS; REANALYSIS; ANOMALIES; PRESSURE; OKHOTSK; EXTENTS; SURGES AB Sea ice variability in the North Pacific and its associations with the east Asia-North Pacific winter climate were investigated using observational data. Two dominant modes of sea ice variability in the North Pacific were identified. The first mode features a dipole pattern between the Sea of Okhotsk and the Bering Sea. The second mode is characterized by more uniform ice changes throughout the North Pacific. Using the principal components of the two dominant modes as the indices ( PC1 and PC2), analyses show that the positive phases of PC1 feature a local warming ( cooling) in the Sea of Okhotsk ( the Bering Sea), which is associated with the formation of the anomalous anticyclone extending from the northern Pacific to Siberia, accompanied by a weakening of the east Asian jet stream and trough. The associated anomalous southeasterlies/easterlies reduce the climatological northwesterlies/westerlies, leading to warm and wet conditions in northeast China and central Siberia. The positive phases of PC2 are characterized by a strong local warming in the northern Pacific that coincides with the anomalous cyclone occupying the entire North Pacific, accompanied by a strengthening of the east Asia jet stream and trough. The associated anomalous northerlies intensify the east Asian winter monsoon (EAWM), leading to cold and dry conditions in the east coast of Asia. The intensified EAWM also strengthens the local Hadley cell, which in turn strengthens the east Asian jet stream and leads to a precipitation deficit over subtropical east Asia. The linkages between PC1 and PC2 and large-scale modes of climate variability were also discussed. It is found that PC1 is a better indicator than the Arctic Oscillation of the recent Siberian warming, whereas PC2 may be a valuable predictor of EAWM. C1 Chinese Acad Sci, LASG, Inst Atmospher Phys, State Key Lab Numer Modeling Atmospher Sci & Geop, Beijing 100029, Peoples R China. Polar Res Inst China, Key Lab Polar Sci, Shanghai, Peoples R China. Columbia Univ, Dept Earth & Environm Sci, New York, NY USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Chinese Acad Meteorol Sci, Beijing, Peoples R China. RP Liu, JP (reprint author), Chinese Acad Sci, LASG, Inst Atmospher Phys, State Key Lab Numer Modeling Atmospher Sci & Geop, POB 9804, Beijing 100029, Peoples R China. EM jliu@lasg.iap.ac.cn RI LIU, JIPING/N-6696-2016 NR 29 TC 12 Z9 14 U1 0 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAY PY 2007 VL 20 IS 10 BP 1991 EP 2001 DI 10.1175/JCLI4105.1 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 173WF UT WOS:000246902500003 ER PT J AU Ju, JY Morgan, RJ Creasy, TS Shin, EE AF Ju, Jaehyung Morgan, Roger J. Creasy, Terry S. Shin, E. Eugene TI Transverse cracking of M40J/PMR-II-50 composites under thermal-mechanical loading: Part II - Experiment and analytical investigation SO JOURNAL OF COMPOSITE MATERIALS LA English DT Article DE M40J/PMR-II-50 (carbon fiber/polyimide composites); thermal cycling; microcracks; interfacial failure; high temperature failure ID CARBON FIBER/EPOXY COMPOSITES; NANOSCALE PROPERTY VARIATIONS; MATRIX CRACKING; CRYOGENIC MICROCRACKING; DAMAGE; FATIGUE; TEMPERATURES; BEHAVIOR; DURABILITY; SYSTEMS AB In this study, the effects of thermal cycling combined with mechanical loading on the microcracking of M40J/PMR-II-50 are investigated. Characterization of the failure mechanisms are conducted based on the critical parameters which cause composite microcracking, as presented in Part I. Based on the test results in Part I, the tests with intermediate in-plane lamina strain (0.175-0.350%) and an increased number of thermal cycles are added. Elevated temperature thermal cycling (23-250 degrees C) is also added to the original test plan to investigate the thermal cycling temperature amplitude effect on microcracking of the composites. Observations indicate that the elevated temperature exposure under mechanical loads causes an easy fiber/matrix debonding. Subsequent exposure to cryogenic temperatures results in fiber/matrix debonding due to the high thermal stresses associated with fiber/matrix thermal expansion mismatch. Crack propagation under cryogenic exposures is shown to be dominant with an increasing number of thermal cycles, especially when combined with high temperature exposure associated with high amplitude of cyclic thermal stresses. C1 Texas A&M Univ, Dept Mech Engn, College Stn, TX 77843 USA. NASA, Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP Ju, JY (reprint author), Texas A&M Univ, Dept Mech Engn, College Stn, TX 77843 USA. EM jaehyung@tamu.edu NR 40 TC 4 Z9 4 U1 3 U2 13 PU SAGE PUBLICATIONS LTD PI LONDON PA 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND SN 0021-9983 J9 J COMPOS MATER JI J. Compos Mater. PD MAY PY 2007 VL 41 IS 9 BP 1067 EP 1086 DI 10.1177/0021998306067260 PG 20 WC Materials Science, Composites SC Materials Science GA 173AA UT WOS:000246844700003 ER PT J AU Sullivan, RM Murthy, PLN Mital, SK Palko, JL Cuneo, JC Koenig, JR AF Sullivan, Roy M. Murthy, Pappu L. N. Mital, Subodh K. Palko, Joseph L. Cuneo, Jacques C. Koenig, John R. TI Development of design analysis methods for carbon silicon carbide composite structures SO JOURNAL OF COMPOSITE MATERIALS LA English DT Article DE carbon silicon carbide composites; micromechanics; analytical material modeling; mechanical properties; thermal properties; user-supplied subroutine; UMAT ID OXIDATION AB The stress-strain behavior at room temperature and at 1100 degrees C (2000 degrees F) is measured for two carbon fiber-reinforced silicon carbide (C/SiC) composite materials: a two dimensional (2D) plain-weave quasi-isotropic laminate and a 3D angle interlock woven composite. Previously developed micromechanics-based material models are calibrated by correlating the predicted material property values with the measured values. Four-point beam-bending subelement specimens are fabricated with these two fiber architectures and four-point bending tests are performed at room temperature and at 1100 degrees C. Displacements and strains are measured at the mid-span of the beam and recorded as a function of load magnitude. The calibrated material models are used in concert with a nonlinear finite-element solution using ABAQUS to simulate the structural response of the two materials in the four-point beam bending tests. The structural response predicted by the nonlinear analysis method compared favorably with the measured response for both materials and both test temperatures. Results show that the material models scale-up fairly well from coupons to subcomponent level. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Toledo, Toledo, OH 43606 USA. Connecticut Reserve Technol, Cleveland, OH USA. So Res Inst, Birmingham, AL 35211 USA. RP Sullivan, RM (reprint author), NASA, Glenn Res Ctr, Mail Stop 49-7,21000 Brook Pk Rd, Cleveland, OH 44135 USA. EM Roy.M.Suilivan@grc.nasa.gov NR 9 TC 1 Z9 1 U1 1 U2 5 PU SAGE PUBLICATIONS LTD PI LONDON PA 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND SN 0021-9983 J9 J COMPOS MATER JI J. Compos Mater. PD MAY PY 2007 VL 41 IS 10 BP 1197 EP 1215 DI 10.1177/0021998306067305 PG 19 WC Materials Science, Composites SC Materials Science GA 182UR UT WOS:000247530000003 ER PT J AU Cozmuta, I Mehrez, H AF Cozmuta, I. Mehrez, H. TI DNA modeling within ab initio and empirical methods SO JOURNAL OF COMPUTATIONAL AND THEORETICAL NANOSCIENCE LA English DT Review DE DNA; nanotechnology; ab initio; force field; atomistic simulations; electronic transport; translocation; design; sequencing ID MOLECULAR-DYNAMICS SIMULATIONS; REACTIVE FORCE-FIELD; IMPLICIT SOLVATION MODELS; DENSITY-FUNCTIONAL THEORY; COARSE-GRAINED MODEL; NUCLEIC-ACIDS; POLYMER TRANSLOCATION; ALPHA-HEMOLYSIN; LIQUID WATER; DOUBLE-HELIX AB The realm of DNA-based nanotechnology has recently attracted an immense interest and became the research focus of a multi-disciplinary scientific community. Despite the wide range of ongoing experimental and theoretical efforts related to DNA, several controversial results exist and DNA-based device fabrication remains challenging. These challenges are related to the sequence dependent structural and dynamical properties of the complex polyelectrolyte DNA molecule and the difficulty in controlling ambient conditions and manipulating DNA. Accurate theoretical models should include, besides the DNA molecule, the effects of the surrounding environment and, if important, interactions with other system components. To give a better interpretation of the experimental results and to setup the path for rational design, phenomenological models should be extended to a hierarchical scheme, which includes quantum and atomistic descriptions. The present review summarizes major developments in the field of DNA modeling from ab initio to empirical. First principles based description of DNA addresses its electronic and transport characteristics within Hartree-Fock, Density Functional Theory, and Tight Binding approximations at different ambient conditions. The empirical description of DNA summarizes frequently employed classical potentials for atomic interactions extending to modern force fields, which include charge equilibration, polarization, and reactive potentials. Studies using full atom and coarse grain models under various environmental conditions using different force fields are also overviewed. DNA translocation through nanometer-sized pores is presently one of the most controversial and challenging problems and it is a major focus of this review article from a simulation standpoint. C1 Eloret Corp, NASA Ames Res Ctr, Moffett Field, CA 94035 USA. RP Cozmuta, I (reprint author), Eloret Corp, NASA Ames Res Ctr, Mail Stop 230-3, Moffett Field, CA 94035 USA. NR 321 TC 4 Z9 4 U1 0 U2 5 PU AMER SCIENTIFIC PUBLISHERS PI VALENCIA PA 26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA SN 1546-1955 EI 1546-1963 J9 J COMPUT THEOR NANOS JI J. Comput. Theor. Nanosci. PD MAY PY 2007 VL 4 IS 3 BP 349 EP 383 PG 35 WC Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 175BT UT WOS:000246987900001 ER PT J AU Trawny, N Mourikis, AI Roumeliotis, SI Johnson, AE Montgomery, JF AF Trawny, Nikolas Mourikis, Anastasios I. Roumeliotis, Stergios I. Johnson, Andrew E. Montgomery, James F. TI Vision-aided inertial navigation for pin-point landing using observations of mapped landmarks SO JOURNAL OF FIELD ROBOTICS LA English DT Article ID POSE ESTIMATION; ATTITUDE AB In this paper we describe an extended Kalman filter algorithm for estimating the pose and velocity of a spacecraft during entry, descent, and landing. The proposed estimator combines measurements of rotational velocity and acceleration from an inertial measurement unit (IMU) with observations of a priori mapped landmarks, such as craters or other visual features, that exist on the surface of a planet. The tight coupling of inertial sensory information with visual cues results in accurate, robust state estimates available at a high bandwidth. The dimensions of the landing uncertainty ellipses achieved by the proposed algorithm are three orders of magnitude smaller than those possible when relying exclusively on IMU integration. Extensive experimental and simulation results are presented, which demonstrate the applicability of the algorithm on real-world data and analyze the dependence of its accuracy on several system design parameters. (C) 2007 Wiley Periodicals, Inc. C1 Univ Minnesota, Dept Comp Sci & Engn, Minneapolis, MN 55455 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Trawny, N (reprint author), Univ Minnesota, Dept Comp Sci & Engn, Minneapolis, MN 55455 USA. EM trawny@cs.umn.edu; mourikis@cs.umn.edu; stergios@cs.umn.edu; andrew.e.johnson@jpl.nasa.gov; james.f.montgomery@jpl.nasa.gov NR 38 TC 61 Z9 69 U1 3 U2 5 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1556-4959 EI 1556-4967 J9 J FIELD ROBOT JI J. Field Robot. PD MAY PY 2007 VL 24 IS 5 BP 357 EP 378 DI 10.1002/rob.20189 PG 22 WC Robotics SC Robotics GA 165CZ UT WOS:000246282800002 ER PT J AU Castano, R Estlin, T Anderson, RC Gaines, DM Castano, A Bornstein, B Chouinard, C Judd, M AF Castano, Rebecca Estlin, Tara Anderson, Robert C. Gaines, Daniel M. Castano, Andres Bornstein, Benjamin Chouinard, Caroline Judd, Michele TI OASIS: Onboard autonomous science investigation system for opportunistic rover science SO JOURNAL OF FIELD ROBOTICS LA English DT Article ID ARCHITECTURE; SHAPE AB The Onboard Autonomous Science Investigation System has been developed to enable a rover to identify and react to serendipitous science opportunities. Using the FIDO rover in the Mars Yard at JPL, we have successfully demonstrated a fully autonomous opportunistic science system. The closed loop system tests included the rover acquiring image data, finding rocks in the image, analyzing rock properties and identifying rocks that merit further investigation. When the system on the rover alerts the rover to take additional measurements of interesting rocks, the planning and scheduling component determines if there are enough resources to meet this additional science data request. The rover is then instructed to either turn toward the rock, or to actually move closer to the rock to take an additional, close-up image. Prototype dust devil and cloud detection algorithms were delivered to an infusion task which refined the algorithms specifically for Mars Exploration Rovers (MER). These algorithms have been integrated into the MER flight software and were recently uploaded to the rovers on Mars. (C) 2007 Wiley Periodicals, Inc. C1 CALTECH, Jet Prop Lab, Div Sci, Pasadena, CA 91109 USA. RP Castano, R (reprint author), CALTECH, Jet Prop Lab, Div Sci, 4800 Oak Grove Dr,MS 126-347, Pasadena, CA 91109 USA. EM Rebecca.Castano@jpl.nasa.gov; Tara.Estlin@jpl.nasa.gov; Robert.C.Anderson@jpl.nasa.gov; Daniel.M.Gaines@jpl.nasa.gov; Andres.Castano@jpl.nasa.gov; Benjamin.Bornstein@jpl.nasa.gov; Caroline.Chouinard@jpl.nasa.gov; Michele.judd@jpl.nasa.gov NR 36 TC 22 Z9 22 U1 0 U2 3 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1556-4959 EI 1556-4967 J9 J FIELD ROBOT JI J. Field Robot. PD MAY PY 2007 VL 24 IS 5 BP 379 EP 397 DI 10.1002/rob.20192 PG 19 WC Robotics SC Robotics GA 165CZ UT WOS:000246282800003 ER PT J AU Bajracharya, M DiCicco, M Backes, P Nickels, K AF Bajracharya, Max DiCicco, Matthew Backes, Paul Nickels, Kevin TI Visual end-effector position error compensation for planetary robotics SO JOURNAL OF FIELD ROBOTICS LA English DT Article ID TASKS AB This paper describes a vision-guided manipulation algorithm that improves arm end-effector positioning to subpixel accuracy and meets the highly restrictive imaging and computational constraints of a planetary robotic flight system. Analytical, simulation-based, and experimental analyses of the algorithm's effectiveness and sensitivity to camera and arm model error is presented along with results on several prototype research systems and '' ground-in-the-loop '' technology experiments on the Mars Exploration Rover (MER) vehicles. A computationally efficient and robust subpixel end-effector fiducial detector that is instrumental to the algorithm's ability to achieve high accuracy is also described along with its validation results on MER data. (C) 2007 Wiley Periodicals, Inc. C1 CALTECH, Jet Prop Lab, Mobil & Manipulat Grp 3473, Pasadena, CA 91109 USA. RP Bajracharya, M (reprint author), CALTECH, Jet Prop Lab, Mobil & Manipulat Grp 3473, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM maxb@robotics.jpl.nasa.gov NR 27 TC 6 Z9 6 U1 0 U2 0 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1556-4959 EI 1556-4967 J9 J FIELD ROBOT JI J. Field Robot. PD MAY PY 2007 VL 24 IS 5 BP 399 EP 420 DI 10.1002/rob.20186 PG 22 WC Robotics SC Robotics GA 165CZ UT WOS:000246282800004 ER PT J AU Wilcox, BH Litwin, T Biesiadecki, J Matthews, J Heverly, M Morrison, J Townsend, J Ahmad, N Sirota, A Cooper, B AF Wilcox, Brian H. Litwin, Todd Biesiadecki, Jeff Matthews, Jaret Heverly, Matt Morrison, Jack Townsend, Julie Ahmad, Norman Sirota, Allen Cooper, Brian TI ATHLETE: A cargo handling and manipulation robot for the moon SO JOURNAL OF FIELD ROBOTICS LA English DT Article AB A robotic vehicle called ATHLETE-the All-Terrain Hex-Limbed, Extra-Terrestrial Explorer-is described, along with initial results of field tests of two prototype vehicles. This vehicle concept is capable of efficient rolling mobility on moderate terrain and walking mobility on extreme terrain. Each limb has a quick-disconnect tool adapter so that it can perform general-purpose handling, assembly, maintenance, and servicing tasks using any or all of the limbs. (C) 2007 Wiley Periodicals, Inc. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wilcox, BH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 303-300, Pasadena, CA 91109 USA. EM Brian.H.Wilcox@jpl.nasa.gov; Todd.E.Litwin@jpl.nasa.gov; Jeffrey.J.Biesiadecki@jpl.nasa.gov; Jaret.B.Matthews@jpl.nasa.gov; Matthew.C.Heverly@jpl.nasa.gov; Jack.C.Morrison@jpl.nasa.gov; Julie.A.Townsend@jpl.nasa.gov; Norman.M.Ahmad@jpl.nasa.gov; Allen.R.Sirota@jpl.nasa.gov; Brian.K.Cooper@jpl.nasa.gov NR 23 TC 92 Z9 99 U1 0 U2 6 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 1556-4959 J9 J FIELD ROBOT JI J. Field Robot. PD MAY PY 2007 VL 24 IS 5 BP 421 EP 434 DI 10.1002/rob.20193 PG 14 WC Robotics SC Robotics GA 165CZ UT WOS:000246282800005 ER PT J AU Kahn, BH Fishbein, E Nasiri, SL Eldering, A Fetzer, EJ Garay, MJ Lee, SY AF Kahn, Brian H. Fishbein, Evan Nasiri, Shaima L. Eldering, Annmarie Fetzer, Eric J. Garay, Michael J. Lee, Sung-Yung TI The radiative consistency of Atmospheric Infrared Sounder and Moderate Resolution Imaging Spectroradiometer cloud retrievals SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MICROPHYSICAL PROPERTY RETRIEVALS; RADIANCE MEASUREMENTS; OBJECTIVE ASSESSMENT; INFORMATION-CONTENT; CIRRUS CLOUDS; GLOBAL OCEANS; WATER-VAPOR; MODIS DATA; AIRS; PRODUCTS AB The consistency of cloud top temperature (T-C) and effective cloud fraction (f) retrieved by the Atmospheric Infrared Sounder (AIRS)/Advanced Microwave Sounding Unit (AMSU) observation suite and the Moderate Resolution Imaging Spectroradiometer (MODIS) on the EOS-Aqua platform are investigated. Collocated AIRS and MODIS T-C and f are compared via an "effective scene brightness temperature" (T-b,T-e). T-b,T-e is calculated with partial field of view (FOV) contributions from T-C and surface temperature (T-S), weighted by f and 1-f, respectively. AIRS reports up to two cloud layers while MODIS reports up to one. However, MODIS reports T-C, T-S, and f at a higher spatial resolution than AIRS. As a result, pixel-scale comparisons of T-C and f are difficult to interpret, demonstrating the need for alternatives such as T-b,T-e. AIRS-MODIS T-b,T-e differences (Delta T-b,T-e) for identical observing scenes are useful as a diagnostic for cloud quantity comparisons. The smallest values of Delta T-b,T-e are for high and opaque clouds, with increasing scatter in Delta(Tb,e) for clouds of smaller opacity and lower altitude. A persistent positive bias in Delta T-b,T-e is observed in warmer and low-latitude scenes, characterized by a mixture of MODIS CO2 slicing and 11-mu m window retrievals. These scenes contain heterogeneous cloud cover, including mixtures of multilayered cloudiness and misplaced MODIS cloud top pressure. The spatial patterns of Delta T-b,T-e are systematic and do not correlate well with collocated AIRS-MODIS radiance differences, which are more random in nature and smaller in magnitude than Delta T-b,T-e. This suggests that the observed inconsistencies in AIRS and MODIS cloud fields are dominated by retrieval algorithm differences, instead of differences in the observed radiances. The results presented here have implications for the validation of cloudy satellite retrieval algorithms, and use of cloud products in quantitative analyses. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX USA. Univ Calif Los Angeles, Dept Atmospher & Ocean Sci, Los Angeles, CA USA. RP Kahn, BH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 169-237, Pasadena, CA 91109 USA. EM brian.h.kahn@jpl.nasa.gov RI Nasiri, Shaima/C-8044-2011 NR 47 TC 17 Z9 17 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 1 PY 2007 VL 112 IS D9 AR D09201 DI 10.1029/2006JD007486 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 165LG UT WOS:000246306400001 ER PT J AU Xia, CY Wang, PKC Hadaegh, FY AF Xia, C. Y. Wang, P. K. C. Hadaegh, F. Y. TI Optimal formation reconfiguration of multiple spacecraft with docking and undocking capability SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article; Proceedings Paper CT AIAA Guidance, Navigation and Control Conference CY SEP 15-18, 2005 CL San Francisco, CA SP AIAA AB Optimal control problems associated with the formation reconfiguration of multiple spacecraft with docking and undocking capability are considered. The basic approach is to deal only with a class of simple formation reconfiguration maneuvers. Then the optimal formation reconfiguration problem is solved by decomposing it into several simple optimal control problems. Explicit solutions of the minimum-fuel and minimum-control energy problems for reconfiguration of simple formation patterns formed by simultaneous docking of multiple spacecraft are obtained. Simulation results are presented to show the nature of the optimal controls and maneuvers for simple formation reconfiguration scenarios. C1 Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Xia, CY (reprint author), Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA. NR 13 TC 6 Z9 7 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAY-JUN PY 2007 VL 30 IS 3 BP 694 EP 702 DI 10.2514/1.27061 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 167RP UT WOS:000246469100007 ER PT J AU Turner, TL Patel, HD AF Turner, Travis L. Patel, Hemant D. TI Analysis of SMA hybrid composite structures in MSC.Nastran and ABAQUS SO JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES LA English DT Article DE shape memory alloys; nitinol; SMA hybrid composites; MSC.Nastran; ABAQUS; finite element analysis; post-buckling control; vibration control; shape control; deflection control ID SHAPE-MEMORY-ALLOY; MULTIVARIANT MICROMECHANICAL MODEL; NITINOL-REINFORCED PLATES; THERMOELASTIC MODEL; FABRICATION; BEHAVIOR AB A thermoelastic constitutive model for shape memory alloy (SMA) actuators embedded in a composite structure, termed an SMA hybrid composite (SMAHC), was recently implemented in the commercial finite element codes MSC.Nastran and ABAQUS. The model can be easily implemented in any code that has the capability for analysis of laminated composite structures with temperature-dependent material properties. The model is also relatively easy to use, and requires input of only fundamental engineering properties. A brief description of the model is presented, followed by a discussion of implementation and usage in commercial codes. Results are presented from static and dynamic analysis of SMAHC beams of two types: a beam clamped at each end and a cantilever beam. Nonlinear static (post-buckling) and random response analyses are demonstrated for the first specimen. Static deflection (shape) control is demonstrated for the cantilever beam. Approaches for modeling SMAHC material systems with embedded SMA in ribbon and small round wire product forms are demonstrated and compared. The results from commercial codes are compared with those from a research code as validation of commercial implementations; excellent correlation is achieved in all the cases. C1 NASA, Langley Res Ctr, Struct Acoust Branch, Hampton, VA 23681 USA. MSC Software Corp, Los Angeles, CA 90041 USA. RP Turner, TL (reprint author), NASA, Langley Res Ctr, Struct Acoust Branch, Hampton, VA 23681 USA. EM t.l.turner@larc.nasa.gov NR 25 TC 10 Z9 10 U1 0 U2 8 PU SAGE PUBLICATIONS LTD PI LONDON PA 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND SN 1045-389X J9 J INTEL MAT SYST STR JI J. Intell. Mater. Syst. Struct. PD MAY PY 2007 VL 18 IS 5 BP 435 EP 447 DI 10.1177/1045389X06066699 PG 13 WC Materials Science, Multidisciplinary SC Materials Science GA 163SJ UT WOS:000246183200002 ER PT J AU Chuang, WH Fettig, RK Ghodssi, R AF Chuang, Wen-Hsien Fettig, Rainer K. Ghodssi, Reza TI Nano-scale fatigue study of LPCVD silicon nitride thin films using a mechanical-amplifier actuator SO JOURNAL OF MICROMECHANICS AND MICROENGINEERING LA English DT Article ID MICROSHUTTER ARRAYS; FABRICATION; AFM AB This paper describes a nano-scale tensile test to study the fatigue properties of LPCVD silicon nitride thin films using a novel electrostatic actuator design. Mechanical-amplifier devices made in silicon nitride thin films can apply controllable tensile stress (2.0-7.8 GPa) to test structures with relatively low actuation voltages (5.7-35.4 V-RMS) at the resonant frequencies of the devices. The test devices are fabricated using a surface micromachining technique in combination with deep reactive ion etching and ion milling. With the recently developed experimental techniques inside a focused-ion-beam system, in situ fatigue measurements are performed on silicon nitride test structures with beam widths of 200 nm. The silicon nitride test structures are found to exhibit time-delayed failures with continuous increases in their compliance. By reducing the applied tensile stress to 3.8 GPa, the test structures can survive cyclic loadings up to 10(8) cycles. C1 Univ Maryland, Dept Elect & Comp Engn, MEMS Sensors & Acuators Lab, College Pk, MD 20742 USA. Univ Maryland, Syst Res Inst, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Chuang, WH (reprint author), Univ Maryland, Dept Elect & Comp Engn, MEMS Sensors & Acuators Lab, College Pk, MD 20742 USA. NR 19 TC 13 Z9 13 U1 0 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0960-1317 J9 J MICROMECH MICROENG JI J. Micromech. Microeng. PD MAY PY 2007 VL 17 IS 5 BP 938 EP 944 DI 10.1088/0960-1317/17/5/013 PG 7 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Instruments & Instrumentation; Physics, Applied SC Engineering; Science & Technology - Other Topics; Instruments & Instrumentation; Physics GA 168VH UT WOS:000246551600015 ER PT J AU Toth, RA Miller, CE Brown, LR Devi, VM Benner, DC AF Toth, R. A. Miller, C. E. Brown, L. R. Devi, V. Malathy Benner, D. Chris TI Line positions and strengths of (OCO)-O-16-C-12-O-18, (OCO)-O-18-C-12-O-18 and (OCO)-O-17-C-12-O-18 between 2200 and 7000 cm(-1) SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article DE carbon dioxide; isotopes; line positions; intensities near infrared ID NEAR-INFRARED SPECTROSCOPY; CARBON-DIOXIDE ISOTOPOLOGUES; SELF-BROADENED WIDTHS; CW-CAVITY RINGDOWN; MU-M; FREQUENCY MEASUREMENTS; BANDS; INTENSITIES; REGION; (CO2)-C-12-O-16 AB Line positions and strengths of (OCO)-O-16-C-12-O-18 (628) (OCO)-O-18-C-12-O-18 (828) and (OCO)-O-11-C-12-O-18 (728) were measured between 2200 and 7000 cm(-1) usina 22 near infrared (NIR) absorption spectra recorded at 0.01-0.013 cm(-1) resolution with the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory on Kitt Peak, Arizona. These data were obtained at room temperature using absorption cells with optical path lengths ranging from 2.4 to 385 m; the cells were filled with natural and O-18-enriched samples of CO, at pressures ranging from 0.54 to 252 torr. The observed line positions were analyzed to obtain the upper state band centers and rotational constants for 17 bands of (OCO)-O-16-C-12-O-18, 19 bands of (OCO)-O-18-C-12-O-18 and 8 bands of (OCO)-O-17-C-12-O-18. The majority of the (OCO)-O-18-C-12-O-18 and (OCO)-O-17-C-12-O-18 bands were measured for the first time. In addition, the rotational constants for the lower states 00001, 01101e and 01101f were derived for all three species using the method of combination differences in which the averaged values obtained from the line positions of two or more bands were least-squares-fitted. Rovibrational parameters were also obtained for the 02201e, 02201f, 10002 and 10001 states of (OCO)-O-18-C-12-O-18. The line position analysis revealed that transitions of the levels 38 <= J' <= 46 of the 11111f <- 01101f band of (OCO)-O-18-C-12-O-18 are perturbed. Perturbed transitions were also observed for the 12212 <- 02201 band and in the hivh-J transitions (J' >= 49) of the 20012 <- 00001 band of (OCO)-O-18-C-12-O-18. Band strengths and Herman-Wallis-like F-factor coefficients were determined for 21 bands of (OCO)-O-16-C-12-O-18, 25 bands of (OCO)-O-18-C-12-O-18 and 8 bands of (OCO)-O-17-C-12-O-18 from least-squares fits to more than 3700 measured transition intensities; band strengths and line positions for 34 of these bands were obtained for the first time. (c) 2007 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. RP Toth, RA (reprint author), CALTECH, Jet Prop Lab, MS 183-301,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Robert.A.Toth@jpl.nasa.gov NR 32 TC 44 Z9 44 U1 1 U2 9 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD MAY PY 2007 VL 243 IS 1 BP 43 EP 61 DI 10.1016/j.jms.2007.03.005 PG 19 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 183YV UT WOS:000247609200006 ER PT J AU Illingsworth, ML Dai, HX Wang, W Chow, D Siochi, EJ Yang, KW Leiston-Belanger, JM Jankauskas, J AF Illingsworth, Marvin L. Dai, Huixiong Wang, Wei Chow, Derek Siochi, Emilie J. Yang, Kenwan Leiston-Belanger, Julie M. Jankauskas, Jennifer TI Pendent polyimides using mellitic acid dianhydride. II. Structure-property relationships for zirconium-containing pendent polymers SO JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY LA English DT Article DE atomic oxygen; differential scanning calorimetry (DSC); functionalization of polymers; gel permeation chromatography (GPC); high-performance polymers; mellitic acid dianhydride; pendent polymer; polyimide; step-growth polymerization; thermal properties; zirconium ID LOW-EARTH-ORBIT; AROMATIC TETRACARBOXYLIC DIANHYDRIDES; TRIFLUOROMETHYL-SUBSTITUTED BENZENE; ISOMERIC BIPHENYL POLYIMIDES; ETHER CONNECTING GROUPS; ATOMIC OXYGEN EROSION; SIDE-CHAIN; FLUORINATED POLYIMIDES; MOLECULAR-STRUCTURE; SOLUBLE POLYIMIDES AB Using mellitic acid dianhydride to prepare Zr-containing pendent copolyimides (co-Pls) is currently being evaluated as a means of further increasing Zr concentration and atomic oxygen resistance while retaining other desirable film properties. The immediate objectives en route to this ultimate goal are: (1) to address the increased tendency of copolyamic acids (co-PAAs) to undergo gelation during polymerizations and upon addition of dicyclohexylcarbodiimide during the Zr appending reactions, and (2) for multilayer films, to increase the number of layers that can be applied prior to crack formation. To accomplish these two objectives, a targeted structure-property study has been performed, holding the Zr concentration constant at 10 mol %. The polymer starting materials chosen for this investigation include PMDA and OPDA (dianhydrides), and 4,4'-ODA, 3,4'-ODA, and 1,3-APB (diamines). The spectroscopic data for all polymer products are consistent with the expected amic acid, imide, pendent, and nonpendent structures. Thin-layer chromatography, viscosity, and gel permeation chromatography (GPC) results confirm the polymeric nature of the Zr pendent and nonpendent co-PAA precursors, with intrinsic viscosities (eta(0)) of 0.86-0.46 for the former and 0.76-0.38 for the latter. Weight-average molecular weights are estimated from GPC to be 115,400-436,000 g/mol for the former and 38,300-111,200 g/mol for the latter. While there was little observable effect of structure change on tendency to form gel, APB-containing Zr pendent copolyimide had the lowest glass transition temperature and allowed the largest number of layers to be cast in a single film without cracking (10 layers) of the pendent copolyimides in this study. (c) 2007 Wiley Periodicals, Inc. C1 Rochester Inst Technol, Dept Chem, Rochester, NY 14623 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Illingsworth, ML (reprint author), Rochester Inst Technol, Dept Chem, Rochester, NY 14623 USA. EM mlisch@rit.edu RI Belanger, Julie/A-5734-2009 OI Belanger, Julie/0000-0002-7236-2778 NR 79 TC 4 Z9 4 U1 2 U2 11 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 0887-624X J9 J POLYM SCI POL CHEM JI J. Polym. Sci. Pol. Chem. PD MAY 1 PY 2007 VL 45 IS 9 BP 1641 EP 1652 DI 10.1002/pola.21931 PG 12 WC Polymer Science SC Polymer Science GA 158XX UT WOS:000245830000007 ER PT J AU Katz, I Mikellides, IG Polk, JE Goebel, DM Hornbeck, SE AF Katz, Ira Mikellides, Ioannis G. Polk, James E. Goebel, Dan M. Hornbeck, Sarah E. TI Thermal model of the hollow cathode using numerically simulated plasma fluxes SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT International Electric Propulsion Conference CY NOV, 2005 CL Princeton, NJ AB The first results from a hollow cathode thermal model are presented. The thermal model uses the spatially distributed plasma fluxes, calculated by a two-dimensional axisymmetric model of the plasma inside the emitter region, as the beat source to predict the hollow cathode and insert temperatures. The computed insert temperature profiles are compared with measured values for a cathode similar to the 0.635-cm diameter discharge cathode used in the NASA-solar electric propulsion technology applications readiness ion engine. The insert temperatures can be used to predict cathode life from barium depletion. The present results and related experimental studies yield three important conclusions. First, the emitter in the NASA solar electric propulsion technology applications readiness hollow cathode does not operate in the emission-limited regime. The thermionic electron current is about 20 A higher than the discharge current and requires significant reverse electron flux from the plasma to satisfy current continuity. Second, the high-plasma density near the centerline of the cathode results in power deposition on the orifice plate that is more than twice the emitter power deposition. Third, despite a higher heat load to the orifice plate, the operating temperature where it would be measured by a thermocouple is approximately 100 degrees C lower than the emitter. The lower orifice plate temperature is due to poor thermal contact between the emitter and the cathode tube and higher than anticipated radiative losses from the external surface of the heater. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Adv Prop Technol Grp, Pasadena, CA 91109 USA. Thermal & Prop Engn Sect, Pasadena, CA 91109 USA. RP Katz, I (reprint author), Adv Prop Technol Grp, 4800 Oak Grove Dr,Mail Stop 125-109, Pasadena, CA 91109 USA. NR 21 TC 5 Z9 5 U1 0 U2 15 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2007 VL 23 IS 3 BP 522 EP 527 DI 10.2514/1.21103 PG 6 WC Engineering, Aerospace SC Engineering GA 170CU UT WOS:000246640300002 ER PT J AU Goebel, DM Watkins, RM Jameson, KK AF Goebel, Dan M. Watkins, Ron M. Jameson, Kristina. K. TI LaB6 hollow cathodes for ion and Hall thrusters SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT AIAA/ASME/SAE/ASEE 41st Joint Propulsion Conference CY JUL 10-13, 2005 CL Tucson, AZ SP AIAA, ASME, SAE, ASEE ID LANTHANUM HEXABORIDE; WORK FUNCTION; FILAMENTS AB Deep space missions and satellite station-keeping applications continue to demand higher power ion thrusters and Hall thrusters capable of providing high thrust and longer life. Depending on the thruster size, the hollow cathodes may be required to produce discharge currents in the 10-100 A range with lifetimes in excess of 10 years. A lanthanum hexaboride (LaB6) hollow cathode has been developed for space applications to increase the current capability from the cathode and ease the handling and gas purity requirements. This cathode uses a LaB6 insert in an all-graphite hollow cathode structure with an integral graphite keeper. Three different sizes of the LaB6 cathode have been successfully operated at discharge currents of up to 100 A to date. Although the LaB6 cathode insert operates at a higher temperature than the conventional BaO dispenser cathode, LaB6 offers the capability of long life and orders of magnitude less sensitivity to propellant impurities and air exposure than conventional dispenser cathodes. C1 CALTECH, Adv Prop Grp, Pasadena, CA 91109 USA. RP Goebel, DM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 33 TC 21 Z9 22 U1 0 U2 16 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2007 VL 23 IS 3 BP 552 EP 558 DI 10.2514/1.25475 PG 7 WC Engineering, Aerospace SC Engineering GA 170CU UT WOS:000246640300006 ER PT J AU Barrett, MJ Johnson, PK AF Barrett, Michael J. Johnson, Paul K. TI Model fidelity requirements for closed-Brayton-cycle space power systems SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID DESIGN C1 Analex Corp, Mech Syst Branch, Cleveland, OH 44135 USA. NASA, John H Glenn Res Ctr Lewis Feld, Thermal Energy Conves Branch, Cleveland, OH 44135 USA. RP Barrett, MJ (reprint author), NASA, John H Glenn Res Ctr Lewis Feld, Thermal Energy Conves Branch, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 15 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2007 VL 23 IS 3 BP 637 EP 640 DI 10.2514/1.20384 PG 4 WC Engineering, Aerospace SC Engineering GA 170CU UT WOS:000246640300016 ER PT J AU Black, JT Leifer, J DeMoss, JA Walker, EN AF Black, Jonathan T. Leifer, Jack DeMoss, Joshua A. Walker, Eric N. TI Experimental and numerical correlation of gravity sag in Solar-SaiR-Quality membranes SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 45th Structures, Structural Dynamics and Materials Conference CY APR 19-22, 2004 CL Palm Springs, CA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC ID PHOTOGRAMMETRY AB Solar sails are among the most studied members of the ultralightweight and inflatable (gossamer) space structures family, due to their potential to provide propellantless propulsion. They are comprised of ultrathin membrane panels that, to date, have proven very difficult to experimentally characterize and numerically model, due to their reflectivity and flexibility and the effects of gravity sag and air damping. Numerical models must be correlated with experimental measurements of subscale solar sails as the first step in verifying that the models can be scaled up to represent full-sized solar sails. In this paper, the surface shapes of two horizontally-supported 25-mu m-thick aluminized Kapton membranes were measured to a 1.0-mm resolution using photogrammetry. Simple numerical models were developed and their output matched the corresponding experimental data in all cases with less than 33% error. This correlation between the numerical predictions and the experimental data is in line with similar results obtained by others who used more complex numerical models to predict the gravity-induced sag of larger sail panels. The results indicate that the largest source of discrepancy between predicted and measured data is membrane slack. It is postulated that incorporation of geometric slack into the numerical models would likely reduce this discrepancy. C1 Univ Kentucky, Lexington, KY 40506 USA. Trinity Univ, Dept Engn Sci, San Antonio, TX 78212 USA. Virginia Polytech Inst & State Univ, Dept Aerosp Engn, Blacksburg, VA 24061 USA. George Washington Univ, Struct Dynam Branch, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Black, JT (reprint author), USAF, Air Force Inst Technol, Wright Patterson Air Force Base, Dept Aeronaut & Astronaut, Wright Patterson AFB, OH 45433 USA. RI Black, Jonathan/R-4875-2016 OI Black, Jonathan/0000-0001-9315-3994 NR 14 TC 3 Z9 3 U1 0 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2007 VL 44 IS 3 BP 522 EP 527 DI 10.2514/1.20958 PG 6 WC Engineering, Aerospace SC Engineering GA 179AP UT WOS:000247262000003 ER PT J AU Chen, T Wang, JT AF Chen, Tzikang Wang, John T. TI Modeling of triangular lattice space structures with curved batten's SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 46th Structures, Structural Dynamics and Materials Conference/1st AIAA Multidisciplinary Design Optimization Specialist Conference CY APR 18-21, 2005 CL Austin, TX SP AIAA, ASME, ASCE, AHS, ASC ID FINITE-ELEMENT; STRENGTH AB Lightweight triangular lattice beams containing longerons, curved battens, and diagonals have been selected for many space structure applications, such as the supporting booms of future solar sails. The curved battens provide the flexibility needed for the booms to be twisted (coiled) and compressed to a small packing volume for reducing the launch cost. An integrated modeling technique for the analysis of triangular lattice beams with curved battens is presented. This modeling technique is used to simulate the assembly process of a lattice beam and to account for the assei ably induced prestresses as well as the curvature of the battens in the subsequent loading response analysis. A key element of this integrated modeling technique is the implementation of a nonlinear cable-pulley element in a general-purpose finite. element code. Finite element models representing different assembled-structure configurations were developed for investigating the effects of design variations on the load-carrying capabilities,. The results indicate that both the curvature of the battens and the prestress state need to be modeled correctly for an accurate prediction of structural response. It is also shown that the loading capabilities of lattice beams can be, significantly reduced if the cable diagonals are not constrained and are allowed to slide freely at the batten-longeron joints. C1 NASA, Langley Res Ctr, Vehicle Technol Directorate, USA,Res Lab,Computat Struct & Mat Branch, Hampton, VA 23681 USA. RP Chen, T (reprint author), NASA, Langley Res Ctr, Vehicle Technol Directorate, USA,Res Lab,Computat Struct & Mat Branch, MS 188E, Hampton, VA 23681 USA. NR 9 TC 2 Z9 2 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2007 VL 44 IS 3 BP 538 EP 544 DI 10.2514/1.22628 PG 7 WC Engineering, Aerospace SC Engineering GA 179AP UT WOS:000247262000005 ER PT J AU Banik, JA Livelyt, PS Taleghani, BK Jenkins, CH AF Banik, Jeremy A. Livelyt, Peter S. Taleghani, Barmac K. Jenkins, Christopher H. TI Solar sail topology variations due to on-orbit thermal effects SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 47th Structures, Structural Dynamics, and Materials Conference CY MAY 01-04, 2006 CL Newport, RI SP AIAA, ASME, ASCE, AHS, ASC AB The objective of this research was to predict the influence of nonuniform temperature distribution on solar sail topology and the effect of such topology variations on sail performance (thrust and torque). Specifically considered were the thermal effects due to on-orbit attitude control maneuvers. Such maneuvers are expected to advance the sail to a position off-normal to the sun by as much as 35 deg; a solar sail initially deformed by typical pretension and solar pressure loads may suffer significant thermally induced strains, due to the nonuniform heating caused by these maneuvers. This on-orbit scenario was investigated through development of an automated analytical shape model that iterates many times between sail shape and sail temperature distribution before converging on a final coupled thermal-structural affected sail topology. This model uses a validated geometrically nonlinear finite element model and a thermal-radiation subroutine. It was discovered that temperature gradients were deterministic for the off-normal solar angle cases, as were thermally induced strains. Performance effects were found to be moderately significant but not as large as initially suspected. A roll torque was detected, and the sail center of pressure shifted by a distance that may influence on-orbit sail control stability. C1 S Dakota Sch Mines & Technol, Compliant Struct Lab, Rapid City, SD 57701 USA. Lockheed Martin Space Operat Co, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Struct Dynam Branch, Hampton, VA 23681 USA. Montana State Univ, Mech & Ind Engn Dept, Bozeman, MT 59717 USA. RP Banik, JA (reprint author), S Dakota Sch Mines & Technol, Compliant Struct Lab, 501 E St Joseph St, Rapid City, SD 57701 USA. NR 20 TC 4 Z9 4 U1 0 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2007 VL 44 IS 3 BP 558 EP 570 DI 10.2514/1.22902 PG 13 WC Engineering, Aerospace SC Engineering GA 179AP UT WOS:000247262000007 ER PT J AU Tessler, A Sleight, DW AF Tessler, Alexander Sleight, David W. TI Geometrically nonlinear shell analysis of wrinkled thin-film membranes with stress concentrations SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 45th Structures, Structural Dynamics and Materials Conference CY APR 19-22, 2004 CL Palm Springs, CA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB Geometrically nonlinear shell finite element analysis has recently been applied to solar sail membrane problems to model the out-of-plane deformations due to structural wrinkling. Whereas certain problems lend themselves to achieving converged nonlinear solutions that compare favorably with experimental observations, solutions to tensioned membranes exhibiting high stress concentrations were difficult to obtain, even with the best nonlinear finite element codes and advanced shell-element technology. In this paper, two numerical studies are presented that pave the way to improving the modeling of this class of nonlinear problems. The studies address the issues of mesh refinement and stress-concentration alleviation and the effects of these modeling strategies on the ability to attain converged nonlinear deformations due to wrinkling. The numerical studies demonstrate that excessive mesh refinement in the regions of stress concentration may be disadvantageous to achieving wrinkled equilibrium states, causing the nonlinear solution to be biased toward the membrane response and totally discarding the very low-energy bending response that is necessary to cause wrinkling-deformation patterns. C1 NASA, Langley Res Ctr, Struct Mech & Concepts Branch, Res & Technol Directorate, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Durabil Damage Tolerance & Reliabil Branch, Res & Technol Directorate, Hampton, VA 23681 USA. RP Tessler, A (reprint author), NASA, Langley Res Ctr, Struct Mech & Concepts Branch, Res & Technol Directorate, Mail Stop 190, Hampton, VA 23681 USA. RI Tessler, Alexander/A-4729-2009 NR 10 TC 12 Z9 13 U1 0 U2 9 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2007 VL 44 IS 3 BP 582 EP 588 DI 10.2514/1.22913 PG 7 WC Engineering, Aerospace SC Engineering GA 179AP UT WOS:000247262000009 ER PT J AU Kornfeld, RP Parrish, JC Sell, S AF Kornfeld, Richard P. Parrish, Joe C. Sell, Steve TI Mars sample return: Testing the last meter of rendezvous and sample capture SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB One of the key challenges of a future Mars sample return mission is the autonomous capture of an orbiting sample canister, previously lofted from the Martian surface, by an Earth Return Vehicle. To accomplish the capture, the latter spacecraft rendezvous with the sample canister and captures it using a capture cone. Understanding the capture dynamics between the sample canister and capture cone in the zero gravity environment is paramount to designing an effective capture mechanism. Moreover, testing and validating the sample capture event in a zero gravity environment is a crucial, though challenging, element to ensure mission success. Although ground-based simulations and flat-floor facilities are cost-effective, they are lacking the required fidelity. On the other hand, space-based testing opportunities provide a true zero gravity environment, but are prohibitive because of their costs. This paper presents a novel, efficient, and cost-effective way to test and validate the "last-meter" rendezvous and capture event. The testing strategy exploits the zero gravity periods provided by NASA's C-9 parabolic aircraft and a novel free-floating test setup that allows the exploration of various capture conditions in a controlled manner. The testing methodology and test hardware are described, and the results and lessons learned from a weeklong flight test campaign are discussed. The methodology and the conclusions described herein can serve as a pathfinder for the test and validation of other zero gravity capture events including those envisioned for future planetary sample return missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Payload Syst Inc, Cambridge, MA 02142 USA. CALTECH, Jet Prop Lab, Syst & Software Div, Pasadena, CA 91109 USA. Payload Syst Inc, Cambridge, MA 02142 USA. RP Kornfeld, RP (reprint author), CALTECH, Jet Prop Lab, Syst & Software Div, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 17 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUTICS ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 EI 1533-6794 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2007 VL 44 IS 3 BP 692 EP 702 DI 10.2514/1.26098 PG 11 WC Engineering, Aerospace SC Engineering GA 179AP UT WOS:000247262000021 ER PT J AU Farley, JF Devine, JW Hadsall, RS AF Farley, Joel F. Devine, Joshua W. Hadsall, Ronald S. TI Professional implications of the expansion of pharmacy-based medical clinics SO JOURNAL OF THE AMERICAN PHARMACISTS ASSOCIATION LA English DT Article DE community and ambulatory pharmacy; pharmacy-based medical clinics; prescriptive authority ID OVER-THE-COUNTER; PHARMACEUTICAL CARE; STATINS AB Objective: To describe challenges and opportunities to the profession of pharmacy associated with the emergence of pharmacy-based medical clinics. Summary: Pharmacy-based medical clinics have emerged as a convenient, low-cost treatment option for many patients. These clinics, which are staffed by physicians' assistants or nurse practitioners, often are located directly within community pharmacies and offer rapid diagnosis and treatment for a limited number of health problems. With plans for significant expansion of these clinics, the profession of pharmacy faces a number of challenges. Allocating space in community pharmacies for medical clinics could place pharmacists at a disadvantage to other providers as they pursue ancillary health care activities. However, these clinics also represent an opportunity for pharmacists to position themselves as legitimized health care providers who are reimbursed for the consultative services they perform. Because most conditions diagnosed at pharmacy-based medical clinics have well-established treatment protocols, pharmacists would be well positioned to provide these services under collaborative practice agreements. This could ultimately provide the resources and payment structure necessary for pharmacists to provide other types of patient care services, including medication therapy management (MTM). Conclusion: As pharmacy-based clinics continue to proliferate, pharmacists should carefully consider surrendering space in community pharmacies to other health care practitioners. These clinics present pharmacists with an opportunity to provide many of the additional health care services for which we have so vigorously argued. Failure to respond to the acute care needs of patients today may present pharmacists with a significant barrier as they continue to expand into direct patient care activities. C1 [Farley, Joel F.] Univ N Carolina, Sch Pharm, Div Pharmaceut Outcome & Policy, Chapel Hill, NC USA. [Devine, Joshua W.] USAF, Dept Def, Pharmacoecon Ctr, Houston, TX USA. [Hadsall, Ronald S.] Univ Minnesota, Coll Pharm, Dept Pharmaceut Care & Hlth Syst, Minneapolis, MN 55455 USA. RP Farley, JF (reprint author), 2201 Kerr Hall,Campus Box 7360, Chapel Hill, NC 27599 USA. EM jffarley@unc.edu NR 29 TC 3 Z9 3 U1 1 U2 2 PU AMER PHARMACEUTICAL ASSOC PI WASHINGTON PA 2215 CONSTITUTION AVE NW, WASHINGTON, DC 20037 USA SN 1544-3191 J9 J AM PHARM ASSOC JI J. Am. Pharm. Assoc. PD MAY-JUN PY 2007 VL 47 IS 3 BP 410 EP 414 DI 10.1331/JAPhA.2007.06093 PG 5 WC Pharmacology & Pharmacy SC Pharmacology & Pharmacy GA 266QP UT WOS:000253452400016 PM 17510039 ER PT J AU Wernet, MP AF Wernet, Mark P. TI Temporally resolved PIV for space-time correlations in both cold and hot jet flows SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Article DE AeroAcoustics; particle image velocimetry; space-time correlations ID PARTICLE IMAGE VELOCIMETRY AB Temporally resolved particle image velocimetry (TR- PIV) is the newest and most exciting tool recently developed to support our continuing efforts to characterize and improve our understanding of the decay of turbulence in jet flows-a critical element for understanding the acoustic properties of the flow. A new TR- PIV system has been developed at the NASA Glenn Research Center which is capable of acquiring planar PIV image frame pairs at up to 25 kHz. The data reported here were collected at Mach numbers of 0.5 and 0.9 and at temperature ratios of 0.89 and 1.76. The field of view of the TR- PIV system covered six nozzle diameters along the lip line of the 50.8 mm diameter jet. The cold flow data at Mach 0.5 were compared with hotwire anemometry measurements in order to validate the new TR- PIV technique. The axial turbulence profiles measured across the shear layer using TR- PIV were thinner than those measured using hotwire anemometry and remained centred along the nozzle lip line. The collected TR- PIV data illustrate the differences in the single point statistical flow properties of cold and hot jet flows. The planar, time-resolved velocity records were then used to compute two-point space-time correlations of the flow at the Mach 0.9 flow condition. The TR- PIV results show that there are differences in the convective velocity and growth rate of the turbulent structures between cold and hot flows at the same Mach number. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Wernet, MP (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 20 TC 42 Z9 42 U1 0 U2 8 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0957-0233 EI 1361-6501 J9 MEAS SCI TECHNOL JI Meas. Sci. Technol. PD MAY PY 2007 VL 18 IS 5 BP 1387 EP 1403 DI 10.1088/0957-0233/18/5/027 PG 17 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 168VW UT WOS:000246553100029 ER PT J AU Wilson, EL Georgieva, EM Heaps, WS AF Wilson, E. L. Georgieva, E. M. Heaps, W. S. TI Development of a Fabry-Perot interferometer for ultra-precise measurements of column CO2 SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Article DE remote sensing; atmospheric composition; absorption; etalon; Fabry-Perot; interferometer; radiometer; carbon dioxide; oxygen; passive ID SOURCE INVERSIONS; UPPER TROPOSPHERE; CARBON-DIOXIDE; SCIAMACHY; SATELLITE; MODEL; CH4; ABSORPTION; TRANSPORT; SOUNDER AB Progress on a passive Fabry-Perot-based instrument for detecting column CO2 through absorption measurements at 1.58 mu m is described. In this design, solar flux reaches the instrument platform and is directed through two channels. In the first channel, transmittance fringes from a Fabry-Perot interferometer are aligned with CO2 absorption lines so that absorption due to CO2 is primarily detected. The second channel encompasses the same frequency region as the first, but is comparatively more sensitive to changes in the solar flux than absorption due to CO2. The ratio of these channels is sensitive to changes in the total CO2 column, but not to changes in solar flux. This inexpensive instrument will offer high precision measurements ( error < 1%) in a compact package. Design of this instrument and preliminary ground-based measurements of column CO2 are presented here as well as strategies for deployment on aircraft and satellite platforms. C1 NASA, Goddard Space Flight Ctr, Laser & Electroopt Branch, Greenbelt, MD 20771 USA. Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RP Wilson, EL (reprint author), NASA, Goddard Space Flight Ctr, Laser & Electroopt Branch, Code 661, Greenbelt, MD 20771 USA. EM Emily.L.Wilson@nasa.gov RI Wilson, Emily/C-9158-2012 OI Wilson, Emily/0000-0001-5634-3713 NR 30 TC 13 Z9 13 U1 0 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0957-0233 EI 1361-6501 J9 MEAS SCI TECHNOL JI Meas. Sci. Technol. PD MAY PY 2007 VL 18 IS 5 BP 1495 EP 1502 DI 10.1088/0957-0233/18/5/040 PG 8 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 168VW UT WOS:000246553100042 ER PT J AU Nurge, MA AF Nurge, Mark A. TI Electrical capacitance volume tomography with high contrast dielectrics using a cuboid sensor geometry SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Article DE electrical capacitance volume tomography; electrical capacitance tomography; image reconstruction; high contrast dielectrics; iterative algorithm; inverse problem; self-capacitance ID IMAGE-RECONSTRUCTION; DESIGN AB An electrical capacitance volume tomography system has been created for use with a new image reconstruction algorithm capable of imaging high contrast dielectric distributions. The electrode geometry consists of two 4 x 4 parallel planes of copper conductors connected through custom built switch electronics to a commercially available capacitance to digital converter. Typical electrical capacitance tomography ( ECT) systems rely solely on mutual capacitance readings to reconstruct images of dielectric distributions. This paper presents a method of reconstructing images of high contrast dielectric materials using only the self-capacitance measurements. By constraining the unknown dielectric material to one of two values, the inverse problem is no longer ill-determined. Resolution becomes limited only by the accuracy and resolution of the measurement circuitry. Images were reconstructed using this method with both synthetic and real data acquired using an aluminium structure inserted at different positions within the sensing region. Comparisons with standard two-dimensional ECT systems highlight the capabilities and limitations of the electronics and reconstruction algorithm. C1 NASA, Kennedy Space Ctr, Kennedy Space Ctr, FL 32899 USA. RP Nurge, MA (reprint author), NASA, Kennedy Space Ctr, KT-D-1, Kennedy Space Ctr, FL 32899 USA. EM Mark.A.Nurge@nasa.gov NR 17 TC 18 Z9 18 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0957-0233 EI 1361-6501 J9 MEAS SCI TECHNOL JI Meas. Sci. Technol. PD MAY PY 2007 VL 18 IS 5 BP 1511 EP 1520 DI 10.1088/0957-0233/18/5/042 PG 10 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 168VW UT WOS:000246553100044 ER PT J AU Woodard, SE Taylor, BD AF Woodard, Stanley E. Taylor, Bryant D. TI Measurement of multiple unrelated physical quantities using a single magnetic field response sensor SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Article DE magnetic field response sensor; wireless data acquisition; fluid-level sensor; wireless temperature sensor; wireless position sensor; phase transformation measurement ID RESONANT-CIRCUIT; WIRELESS AB This paper presents a non-contact method for powering and interrogating magnetic field response sensors that facilitates measurement of multiple unrelated physical quantities using the same sensor. The sensors are electrically passive inductive-capacitive or passive inductive-capacitive-resistive circuits that are powered using oscillating magnetic fields, and once electrically active, the sensors respond with their own oscillating magnetic fields. The sensor's magnetic field response frequency, amplitude and bandwidth are correlated to the magnitude of one or more physical quantities that each sensor measures. The magnetic field response sensors and the technique for powering and interrogation alleviate many shortcomings of traditional sensor/measurement systems. The shortcomings are having a data acquisition channel dedicated to each sensor, wiring/circuitry weight associated with measurements, electrical arcing, wire degradations due to wear or chemical decay and the logistics needed to add new sensors. Because measurements can be derived from influences upon the sensor's magnetic field or electrical field, the circuit that forms the sensor need not be in physical contact with the measurand. The method for discerning sensor response frequency, resistance and amplitude is presented herein. The method does not require the sensors to be near or physically connected to acquisition hardware or a power source. The theoretical basis for the measurement acquisition technique is discussed including the influence of key parameters on measurement acquisition. One example of a magnetic field response sensor for measuring the magnitude of three unrelated physical quantities-material phase transition, temperature and position-will be presented. A fluid-level measurement will also be presented. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Woodard, SE (reprint author), NASA, Langley Res Ctr, Mail Stop 230, Hampton, VA 23681 USA. EM s.e.woodard@larc.nasa.gov; b.d.taylor@larc.nasa.gov NR 16 TC 10 Z9 10 U1 0 U2 8 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0957-0233 EI 1361-6501 J9 MEAS SCI TECHNOL JI Meas. Sci. Technol. PD MAY PY 2007 VL 18 IS 5 BP 1603 EP 1613 DI 10.1088/0957-0233/18/5/052 PG 11 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 168VW UT WOS:000246553100054 ER PT J AU Bhattacharyya, S AF Bhattacharyya, Sudip TI Timing properties of XB 1254-690 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE methods : data analysis; techniques : miscellaneous; stars : neutron; X-rays : binaries; X-rays : bursts; X-rays : individual : XB 1254-690 ID X-RAY-BURSTS; QUASI-PERIODIC OSCILLATION; ROTATING NEUTRON-STARS; BRIGHTNESS OSCILLATIONS; THERMONUCLEAR FLAMES; FREQUENCY EVOLUTION; SPECTRAL BEHAVIOR; RXTE OBSERVATIONS; ABSORPTION-LINES; SPIN FREQUENCY AB We analyse archival Rossi X-ray Timing Explorer Proportional Counter Array data of the low-mass X-ray binary (LMXB) system XB 1254-690. We calculate colour-colour diagram, hardness-intensity diagram and power spectra of this source, associate its broad low-frequency timing features with the portions of the colour-colour diagram, and establish that XB 1254-690 is an atoll source. This will be important to correlate the timing and spectral features of this dipping LMXB with its various states, which may be useful to understand LMXBs in general. We find the source always in the high-intensity banana state, which may explain why similar to 1 Hz 'dipper quasi-periodic oscillations' have never been observed from XB 1254-690. We also report a suggestive evidence of millisecond period brightness oscillations at the frequency similar to 95 Hz during a thermonuclear X-ray burst for the first time from this source. C1 NASA, Goddard Space Flight Ctr, CRESST, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, X Ray Astrophys Lab, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Bhattacharyya, S (reprint author), NASA, Goddard Space Flight Ctr, CRESST, Code 661, Greenbelt, MD 20771 USA. EM sudip@milkyway.gsfc.nasa.gov NR 42 TC 12 Z9 12 U1 0 U2 0 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY PY 2007 VL 377 IS 1 BP 198 EP 202 DI 10.1111/j.1365-2966.2007.11587.x PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 172IQ UT WOS:000246797900035 ER PT J AU Schady, P Mason, KO Page, MJ De Pasquale, M Morris, DC Romano, P Roming, PWA Immler, S Berk, DEV AF Schady, P. Mason, K. O. Page, M. J. De Pasquale, M. Morris, D. C. Romano, P. Roming, P. W. A. Immler, S. Berk, D. E. Vanden TI Dust and gas in the local environments of gamma-ray bursts SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE dust, extinction; galaxies : ISM; gamma-rays : bursts; gamma-rays : observations ID TIME-DEPENDENT PHOTOIONIZATION; LARGE MAGELLANIC CLOUD; INTERSTELLAR DUST; TELESCOPE; ABSORPTION; AFTERGLOWS; SUPERNOVA; EVOLUTION; EMISSION; GRAINS AB Using a sample of gamma-ray burst (GRB) afterglows detected by both the X-Ray Telescope (XRT) and the UV/Optical Telescope (UVOT) on Swift, we modelled the spectral energy distributions (SEDs) to determine gas column densities and dust extinction in the GRB local environment. In six out of seven cases we find an X-ray absorber associated with the GRB host galaxy with column density (assuming solar abundances) ranging from (0.8-7.7) x 10(21) cm(-2). We determine the rest-frame visual extinction A(V) using the Small Magellanic Cloud (SMC), Large Magellanic Cloud (LMC) and Galactic extinction curves to model the dust in the GRB host galaxy, and this ranges from A(V) = 0.12 +/- 0.04 to 0.65(-0.07)(+0.08). The afterglow SEDs were typically best fit by a model with an SMC extinction curve. In only one case was the GRB afterglow better modelled by a Galactic extinction curve, which has a prominent absorption feature at 2175 angstrom. We investigate the selection effects present in our sample and how these might distort the true distribution of A(V) in GRB host galaxies. We estimate that GRBs with no afterglow detected blueward of 5500 angstrom have average rest-frame visual extinctions almost eight times those observed in the optically bright population of GRBs. This may help account for the similar to 1/3 of GRBs observed by Swift that have no afterglow detected by UVOT. C1 UCL Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Particle Phys & Astron Res Ctr, Swindon SN2 1SZ, Wilts, England. INAF, Osserv Astron Brera, I-23807 Merate, LC, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Schady, P (reprint author), UCL Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. EM ps@mssl.ucl.ac.uk NR 57 TC 89 Z9 90 U1 0 U2 1 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY PY 2007 VL 377 IS 1 BP 273 EP 284 DI 10.1111/j.1365-2966.2007.11592.x PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 172IQ UT WOS:000246797900043 ER PT J AU Scaife, A Green, DA Battye, RA Davies, RD Davis, RJ Dickinson, C Franzen, T Genova-Santos, R Grainge, K Hafez, YA Hobson, MP Lasenby, A Pooley, GG Rajguru, N Rebolo, R Rubino-Martin, JA Saunders, RDE Scott, PF Titterington, D Waldram, E Watson, RA AF Scaife, Anna Green, David A. Battye, Richard A. Davies, Rod D. Davis, Richard J. Dickinson, Clive Franzen, Thomas Genova-Santos, Ricardo Grainge, Keith Hafez, Yaser A. Hobson, Michael P. Lasenby, Anthony Pooley, Guy G. Rajguru, Nutan Rebolo, Rafael Rubino-Martin, Jose Alberto Saunders, Richard D. E. Scott, Paul F. Titterington, David Waldram, Elizabeth Watson, Robert A. TI Constraints on spinning dust towards Galactic targets with the Very Small Array: a tentative detection of excess microwave emission towards 3C396 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE radiation mechanisms : general; dust, extinction; ISM : individual : 3C396; radio continuum : ISM ID RADIO-CONTINUUM SURVEY; 11 CM WAVELENGTH; BACKGROUND POWER SPECTRUM; COSMOSOMAS EXPERIMENT; PLANE SURVEY; GHZ; GRAINS; CLOUD; FOREGROUNDS; TELESCOPE AB We present results from observations made at 33 GHz with the Very Small Array (VSA) telescope towards potential candidates in the Galactic plane for spinning dust emission. In the cases of the diffuse H II regions LPH96 and NRAO591 we find no evidence for anomalous emission and, in combination with Effelsberg data at 1.4 and 2.7 GHz, confirm that their spectra are consistent with optically thin free-free emission. In the case of the infrared bright supernova remnant 3C396 we find emission inconsistent with a purely non-thermal spectrum and discuss the possibility of this excess arising from either a spinning dust component or a shallow spectrum pulsar wind nebula, although we conclude that the second case is unlikely given the strong constraints available from lower-frequency radio images. C1 Univ Cambridge, Cavendish Lab, Astrophys Grp, Cambridge CB3 0HE, England. Jodrell Bank Observ, Macclesfield SK11 9DL, Cheshire, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. UCL, Dept Phys & Astron, Astrophys Grp, London WC1E 6BT, England. Inst Astrofis Canarias, San Cristobal la Laguna 38200, Tenerife, Spain. CALTECH, Pasadena, CA 91125 USA. RP Scaife, A (reprint author), Univ Cambridge, Cavendish Lab, Astrophys Grp, 19 JJ Thomson Ave, Cambridge CB3 0HE, England. EM as595@mrao.cam.ac.uk RI Green, David/E-9609-2010; Franzen, Thomas/G-7050-2014; OI Green, David/0000-0003-3189-9998; Rubino-Martin, Jose Alberto/0000-0001-5289-3021; Watson, Robert/0000-0002-5873-0124 NR 39 TC 28 Z9 28 U1 0 U2 1 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY PY 2007 VL 377 IS 1 BP L69 EP L73 DI 10.1111/j.1745-3933.2007.00305.x PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 172IQ UT WOS:000246797900015 ER PT J AU Ponomareva, I Srivastava, D Menon, M AF Ponomareva, Inna Srivastava, Deepak Menon, Madhu TI Thermal conductivity in thin silicon nanowires: Phonon confinement effect SO NANO LETTERS LA English DT Article ID SIMULATION AB Thermal conductivity of thin silicon nanowires (1.4-8.3 nm) including the realistic crystalline structures and surface reconstruction effects is investigated using direct molecular dynamics simulations with Stillinger-Weber potential for Si-Si interactions. Thermal conductivity as a function of decreasing nanowire diameter shows an expected decrease due to increased surface scattering effects. However, at very small diameter (< 1.5 nm), an increase in the thermal conductivity is observed, which is explained by the phonon confinement effect. C1 Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. Univ Kentucky, Ctr Computat Sci, Lexington, KY 40506 USA. Univ Arkansas, Dept Phys, Fayetteville, AR 72701 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Menon, M (reprint author), Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. EM super250@pop.uky.edu RI Ponomareva, Inna/C-4067-2012 NR 15 TC 119 Z9 119 U1 2 U2 43 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1530-6984 J9 NANO LETT JI Nano Lett. PD MAY PY 2007 VL 7 IS 5 BP 1155 EP 1159 DI 10.1021/nl062823d PG 5 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 165NU UT WOS:000246313000009 PM 17394370 ER PT J AU Jacobs, BW Ayres, VM Petkov, MP Halpern, JB He, MQ Baczewski, AD McElroy, K Crimp, MA Zhang, JM Shaw, HC AF Jacobs, Benjamin W. Ayres, Virginia M. Petkov, Mihail P. Halpern, Joshua B. He, Maoqi Baczewski, Andrew D. McElroy, Kaylee Crimp, Martin A. Zhang, Jiaming Shaw, Harry C. TI Electronic and structural characteristics of zinc-blende wurtzite biphasic homostructure GaN nanowires SO NANO LETTERS LA English DT Article ID GALLIUM NITRIDE NANOWIRES; CHEMICAL-VAPOR-DEPOSITION; MOLECULAR-BEAM EPITAXY; GROWTH ORIENTATION; CONTACTS; AMMONIA; NH3; FABRICATION; NANORODS; SURFACE AB We report a new biphasic crystalline wurtzite/zinc-blende homostructure in gallium nitride nanowires. Cathodoluminescence was used to quantitatively measure the wurtzite and zinc-blende band gaps. High-resolution transmission electron microscopy was used to identify distinct wurtzite and zinc-blende crystalline phases within single nanowires through the use of selected area electron diffraction, electron dispersive spectroscopy, electron energy loss spectroscopy, and fast Fourier transform techniques. A mechanism for growth is identified. C1 Michigan State Univ, Dept Elect & Comp Engn, E Lansing, MI 48824 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Howard Univ, Dept Chem, Washington, DC 20059 USA. Michigan State Univ, Dept Chem Engn & Mat Sci, E Lansing, MI 48824 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Jacobs, BW (reprint author), Michigan State Univ, Dept Elect & Comp Engn, 2120 Engn Bldg, E Lansing, MI 48824 USA. EM jacobsbe@egr.msu.edu NR 40 TC 27 Z9 27 U1 2 U2 19 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1530-6984 J9 NANO LETT JI Nano Lett. PD MAY PY 2007 VL 7 IS 5 BP 1435 EP 1438 DI 10.1021/nl062871y PG 4 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 165NU UT WOS:000246313000057 PM 17417913 ER PT J AU Baker, DJ Thurgood, BK Harrison, WK Mlynczak, MG Russell, JM AF Baker, D. J. Thurgood, B. K. Harrison, W. K. Mlynczak, M. G. Russell, J. M. TI Equatorial enhancement of the nighttime OH mesospheric infrared airglow SO PHYSICA SCRIPTA LA English DT Article ID MIDDLE ATMOSPHERE; HYDROXYL AIRGLOW; OXYGEN; CIRCULATION; INTENSITIES; EXCITATION AB Global measurements of the hydroxyl mesospheric airglow over an extended period of time have been made possible by the NASA SABER infrared sensor aboard the TIMED satellite which has been functioning since December of 2001. The orbital mission has continued over a significant portion of a solar cycle. Experimental data from SABER for several years have exhibited equatorial enhancements of the nighttime mesospheric OH (Delta v = 2) airglow layer consistent with the high average diurnal solar flux. The brightening of the OH airglow typically means more H+O-3 is being reacted. At both the spring and autumn seasonal equinoxes when the equatorial solar UV irradiance mean is greatest, the peak volume emission rate (VER) of the nighttime Meinel infrared airglow typically appears to be both significantly brighter plus lower in altitude by several kilometres at low latitudes compared with midlatitude findings. C1 Utah State Univ, Logan, UT 84322 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. RP Baker, DJ (reprint author), Utah State Univ, EL-302, Logan, UT 84322 USA. EM spacegrant@cc.usu.edu RI Mlynczak, Martin/K-3396-2012 NR 30 TC 17 Z9 17 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0031-8949 J9 PHYS SCRIPTA JI Phys. Scr. PD MAY PY 2007 VL 75 IS 5 BP 615 EP 619 DI 10.1088/0031-8949/75/5/004 PG 5 WC Physics, Multidisciplinary SC Physics GA 156YR UT WOS:000245686300004 ER PT J AU Wallbank, B Bannister, ME Krause, HF Chung, YS Smith, ACH Djuric, N Dunn, GH AF Wallbank, B. Bannister, M. E. Krause, H. F. Chung, Y.-S. Smith, A. C. H. Djuric, N. Dunn, G. H. TI Merged-beam measurements of absolute cross sections for electron-impact excitation of S(4+) (3s(2) (1)S -> 3s3p (1)P) and S(5+) (3s (2)S -> 3p (2)P) SO PHYSICAL REVIEW A LA English DT Article ID SODIUM ISOELECTRONIC SEQUENCE; ENERGY-LOSS TECHNIQUE; COLLISION RATES; IONIZATION; IONS; TRANSITIONS; INTENSITIES; SV AB Absolute cross sections for electron-impact excitation of the dipole-allowed transitions S(4+) (3s(2) (1)S -> 3s3p (1)P) and S(5+) (3s (2)S -> 3p (2)P) were measured near threshold using the merged electron-ion beams energy-loss technique. Although the magnitudes of the measured cross sections are in reasonable agreement with available theoretical data, the experimental data indicate that the contributions of dielectronic resonances in the near-threshold region are underestimated by these calculations. C1 St Francis Xavier Univ, Dept Phys, Antigonish, NS B2G 2W5, Canada. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Chungnam Natl Univ, Dept Phys, Taejon 305764, South Korea. UCL, Dept Phys & Astron, London WC1E 6BT, England. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. RP Wallbank, B (reprint author), Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM bannisterme@ornl.gov NR 27 TC 4 Z9 4 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY PY 2007 VL 75 IS 5 AR 052703 DI 10.1103/PhysRevA.75.052703 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 173RO UT WOS:000246890400090 ER PT J AU Florescu, M Busch, K Dowling, JP AF Florescu, Marian Busch, Kurt Dowling, Jonathan P. TI Thermal radiation in photonic crystals SO PHYSICAL REVIEW B LA English DT Article ID EMISSION AB We analyze the properties of thermal radiation in photonic crystals and show that the spectral energy density, the spectral intensity, and the spectral hemispherical power are only limited by the total number of available photonic states and their propagation characteristics. In addition, we show that the central quantity that determines these thermal radiation characteristics is the area of the isofrequency surfaces and not the photonic density of states as it is generally assumed. Through the presence of partial or complete photonic band gaps and the associated spectral and angular redistribution of photonic states, it is possible to have spectral regions over which the thermal radiation intensity is enhanced relative to the free space blackbody limit and propagation directions along which thermal photon focusing effects appear. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. Univ Karlsruhe, Inst Theoret Festkorperphys, D-76128 Karlsruhe, Germany. RP Florescu, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Marian.Florescu@jpl.nasa.gov RI Florescu, Marian/E-9009-2010; DOWLING, JONATHAN/L-2749-2013 NR 24 TC 28 Z9 28 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD MAY PY 2007 VL 75 IS 20 AR 201101 DI 10.1103/PhysRevB.75.201101 PG 4 WC Physics, Condensed Matter SC Physics GA 173RT UT WOS:000246890900001 ER PT J AU Hogan, RC Cuzzi, JN AF Hogan, R. C. Cuzzi, J. N. TI Cascade model for particle concentration and enstrophy in fully developed turbulence with mass-loading feedback SO PHYSICAL REVIEW E LA English DT Article ID PROBABILITY DENSITY-FUNCTIONS; ISOTROPIC TURBULENCE; CHANNEL FLOW AB A cascade model is described based on multiplier distributions determined from three-dimensional (3D) direct numerical simulations (DNS) of turbulent particle laden flows, which include two-way coupling between the phases at global mass loadings equal to unity. The governing Eulerian equations are solved using psuedospectral methods on up to 512(3) computional grid points. DNS results for particle concentration and enstrophy at Taylor microscale Reynolds numbers in the range 34-170 were used to directly determine multiplier distributions on spatial scales three times the Kolmogorov length scale. The multiplier probability distribution functions (PDFs) are well characterized by the beta distribution function. The width of the PDFs, which is a measure of intermittency, decreases with increasing mass loading within the local region where the multipliers are measured. The functional form of this dependence is not sensitive to Reynolds numbers in the range considered. A partition correlation probability is included in the cascade model to account for the observed spatial anticorrelation between particle concentration and enstrophy. Joint probability distribution functions of concentration and enstrophy generated using the cascade model are shown to be in excellent agreement with those derived directly from our 3D simulations. Probabilities predicted by the cascade model are presented at Reynolds numbers well beyond what is achievable by direct simulation. These results clearly indicate that particle mass loading significantly reduces the probabilities of high particle concentration and enstrophy relative to those resulting from unloaded runs. Particle mass density appears to reach a limit at around 100 times the gas density. This approach has promise for significant computational savings in certain applications. C1 Bay Area Environm Res Inst, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Hogan, RC (reprint author), Bay Area Environm Res Inst, MS 245-3, Moffett Field, CA 94035 USA. EM hogan@cosmic.arc.nasa.gov; jcuzzi@mail.arc.nasa.gov NR 15 TC 21 Z9 21 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1539-3755 J9 PHYS REV E JI Phys. Rev. E PD MAY PY 2007 VL 75 IS 5 AR 056305 DI 10.1103/PhysRevE.75.056305 PN 2 PG 9 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 173RM UT WOS:000246890200043 PM 17677162 ER PT J AU Bos, WJT Clark, TT Rubinstein, R AF Bos, Wouter J. T. Clark, Timothy T. Rubinstein, Robert TI Small scale response and modeling of periodically forced turbulence SO PHYSICS OF FLUIDS LA English DT Article ID DIRECT NUMERICAL SIMULATIONS; ISOTROPIC TURBULENCE; MODULATED TURBULENCE; PIPE-FLOW; UNSTEADINESS; SHEAR AB The response of the small scales of isotropic turbulence to periodic large scale forcing is studied using two-point closures. The frequency response of the turbulent kinetic energy and dissipation rate, and the phase shifts among production, energy, and dissipation are determined as functions of the Reynolds number. It is observed that the amplitude and phase of the dissipation exhibit nontrivial frequency and Reynolds number dependence that reveals a filtering effect of the energy cascade. Perturbation analysis is applied to understand this behavior which is shown to depend on distant interactions between widely separated scales of motion. Finally, the extent to which finite dimensional models (standard two-equation models and various generalizations) can reproduce the observed behavior is discussed. (C) 2007 American Institute of Physics. C1 Univ Lyon 1, Ecole Cent Lyon, CNRS, UMR 5509,LMFA,INSA, F-69134 Ecully, France. Tau Technol, Albuquerque, NM USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Bos, WJT (reprint author), Univ Lyon 1, Ecole Cent Lyon, CNRS, UMR 5509,LMFA,INSA, F-69134 Ecully, France. OI Bos, Wouter/0000-0003-3510-0362 NR 28 TC 10 Z9 10 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD MAY PY 2007 VL 19 IS 5 AR 055107 DI 10.1063/1.2728939 PG 11 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 173SL UT WOS:000246892700028 ER PT J AU Kalb, VL Deane, AE AF Kalb, Virginia L. Deane, Anil E. TI An intrinsic stabilization scheme for proper orthogonal decomposition based low-dimensional models SO PHYSICS OF FLUIDS LA English DT Article ID NAVIER-STOKES EQUATIONS; DRIVEN CAVITY FLOW; LOW-ORDER MODELS; COHERENT STRUCTURES; GALERKIN MODELS; SQUARE CYLINDER; PART I; STEP; WAKE AB Despite the temporal and spatial complexity of common fluid flows, model dimensionality can often be greatly reduced while both capturing and illuminating the nonlinear dynamics of the flow. This work follows the methodology of direct numerical simulation (DNS) followed by proper orthogonal decomposition (POD) of temporally sampled DNS data to derive temporal and spatial eigenfunctions. The DNS calculations use Chorin's projection scheme; two-dimensional validation and results are presented for driven cavity and square cylinder wake flows. The flow velocity is expressed as a linear combination of the spatial eigenfunctions with time-dependent coefficients. Galerkin projection of these modes onto the Navier-Stokes equations obtains a dynamical system with quadratic nonlinearity and explicit Reynolds number (Re) dependence. Truncation to retain only the most energetic modes produces a low-dimensional model for the flow at the decomposition Re. We demonstrate that although these low-dimensional models reproduce the flow dynamics, they do so with small errors in amplitude and phase, particularly in their long term dynamics. This is a generic problem with the POD dynamical system procedure and we discuss the schemes that have so far been proposed to alleviate it. We present a new stabilization algorithm, which we term intrinsic stabilization, that projects the error onto the POD temporal eigenfunctions, then modifies the dynamical system coefficients to significantly reduce these errors. It requires no additional information other than the POD. The premise that this method can correct the amplitude and phase errors by fine-tuning the dynamical system coefficients is verified. Its effectiveness is demonstrated with low-dimensional dynamical systems for driven cavity flow in the periodic regime, quasiperiodic flow at Re=10000, and the wake flow. While derived in a POD context, the algorithm has broader applicability, as demonstrated with the Lorenz system. (c) 2007 American Institute of Physics. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, College Pk, MD 20742 USA. RP Kalb, VL (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM Virginia.L.Kalb@nasa.gov; Deane@ipst.umd.edu RI Kalb, Virginia/A-9971-2009 OI Kalb, Virginia/0000-0002-3107-9271 NR 37 TC 17 Z9 17 U1 2 U2 3 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD MAY PY 2007 VL 19 IS 5 AR 054106 DI 10.1063/1.2723149 PG 18 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 173SL UT WOS:000246892700018 ER PT J AU Nielsen, E Morgan, DD Kirchner, DL Plaut, J Picardi, G AF Nielsen, E. Morgan, D. D. Kirchner, D. L. Plaut, J. Picardi, G. TI Absorption and reflection of radio waves in the Martian ionosphere SO PLANETARY AND SPACE SCIENCE LA English DT Article DE Mars; ionosphere; radio wave absorption; top-side sounder ID MARS; ATMOSPHERE AB Radio wave absorption in the Martian ionosphere has been predicted and tested against MARSIS radar observations. Models of the ionosphere densities and of absorption in a CO, neutral atmosphere were used. The appearance of ground reflections in the MARSIS observations is shown to be consistent with predictions of reflection and absorption of radio waves in the ionosphere. It is concluded that the secondary density maximum, known to be typically present below the primary density peak, contributes considerably to the absorption and thus to the appearance of ground reflections. It is the first time predicted radio wave absorption in a CO2 planetary atmosphere has been tested against actual observations. (c) 2006 Elsevier Ltd. All rights reserved. C1 Max Planck Inst Solar Syst Res, D-37191 Katlenburg Lindau, Germany. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Roma La Sapienza, Inforcom Dept, I-00184 Rome, Italy. RP Nielsen, E (reprint author), Max Planck Inst Solar Syst Res, D-37191 Katlenburg Lindau, Germany. EM nielsen@mps.mpg.de NR 13 TC 16 Z9 16 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD MAY PY 2007 VL 55 IS 7-8 BP 864 EP 870 DI 10.1016/j.pss.2006.10.005 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 175MQ UT WOS:000247018100002 ER PT J AU Jaumann, R Neukum, G Behnke, T Duxbury, TC Eichentopf, K Flohrer, J von Gasselt, S Giese, B Gwinner, K Hauber, E Hoffmann, H Hoffmeister, A Kohler, U Matz, KD McCord, TB Mertens, V Oberst, J Pischel, R Reiss, D Ress, E Roatsch, T Saiger, P Scholten, F Schwarz, G Stephan, K Wahlisch, M AF Jaumann, R. Neukum, G. Behnke, T. Duxbury, T. C. Eichentopf, K. Flohrer, J. von Gasselt, S. Giese, B. Gwinner, K. Hauber, E. Hoffmann, H. Hoffmeister, A. Koehler, U. Matz, K.-D. McCord, T. B. Mertens, V. Oberst, J. Pischel, R. Reiss, D. Ress, E. Roatsch, T. Saiger, P. Scholten, F. Schwarz, G. Stephan, K. Waehlisch, M. CA HRSC Co-Investigator Team TI The high-resolution stereo camera (HRSC) experiment on Mars Express: Instrument aspects and experiment conduct from interplanetary cruise through the nominal mission SO PLANETARY AND SPACE SCIENCE LA English DT Article DE planetary missions; Mars; Mars Express; imaging instruments; HRSC; stereo imaging ID HECATES-THOLUS; GROUND ICE; INTERIOR CHANNELS; GLACIAL ACTIVITY; RAMPART CRATERS; LASER ALTIMETER; ORBITER CAMERA; CLIMATE-CHANGE; DEPOSITS; VALLEYS AB ESA's Mars Express has successfully completed its nominal mission of one Martian year covering about 25% of the surface in stereo and color with resolutions up to I Om/pixel by its high-resolution stereo camera (HRSC). Mars Express is now in its extended mission phase, during which much of the remaining part of the Martian surface is envisaged to be covered in stereo and color. The HRSC instrument is designed to map the morphology, topography, structure and geologic context of the surface as well as atmospheric phenomena. This paper discusses the measurement principles and operations of the instrument as well as the acquisition, calibration and processing of regional and global data sets. As HRSC is a push-broom scanning instrument with nine CCD line detectors mounted in parallel on a focal plane, its unique feature is the ability to obtain near-simultaneous imaging data at high resolution, with along-track triple stereo, four colors and five different phase angles, avoiding any time-dependent variations of the observing conditions. The HRSC spatial resolution is 10 m/pixel at the nominal periapsis altitude of 250 km, with an image swath of 53 km, and 2.3 m/pixel for an additional framing CCD device, called super resolution channel (SRC), practically working as an additional tenth channel of the HRSC and yielding nested-in black and white images for studies of small-scale geologic features. The sub-pixel accuracy of the threedimensional point determination allows the derivation of digital terrain models (DTMs) with a grid size of up to 50m and a height accuracy of a single pixel with up to 10 m, thus enabling us to carry out detailed quantitative analyses of the surface structure. The HRSC (1) bridges the gap between the medium-high-resolution Viking imagery and the very- high- resolution Global Surveyor mission, thus providing geological context, and (2) fills the gaps in the three-dimensional coverage and DTM grid of the MOLA laser altimetry data, and (3) helps characterize landing sites for in-situ measurements. HRSC also builds the basis for extended compositional mapping when combining spectral information with topographic photomaps over large areas. So far the HRSC measurements have made a significant contribution to the study of the evolution of volcanism and the role of water and ice throughout the Martian history. (c) 2007 Elsevier Ltd. All rights reserved. C1 Deutsches Zentrum Luft & Raumfahrt DLR, Inst Planetary Res, D-12489 Berlin, Germany. Free Univ Berlin, Dept Earth Sci, Inst Geosci Planetol & Remote Sensing, D-12249 Berlin, Germany. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Bear Fight Ctr, Space Sci Inst, Winthrop, WA 98862 USA. Remote Sensing Technol Inst, Deutsches Zentrum Luft & Raumfahrt DLR, D-82230 Wessling, Germany. RP Jaumann, R (reprint author), Deutsches Zentrum Luft & Raumfahrt DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany. EM ralf.jaumann@dlr.de RI Reiss, Dennis/B-6211-2008; OI Reiss, Dennis/0000-0002-1836-596X; van Gasselt, Stephan/0000-0003-2130-6343 NR 88 TC 180 Z9 183 U1 2 U2 24 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD MAY PY 2007 VL 55 IS 7-8 BP 928 EP 952 DI 10.1016/j.pss.2006.12.003 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 175MQ UT WOS:000247018100008 ER PT J AU Abbas, MM Tankosic, D Craven, PD Spann, JF LeClair, A West, EA AF Abbas, M. M. Tankosic, D. Craven, P. D. Spann, J. F. LeClair, A. West, E. A. TI Lunar dust charging by photoelectric emissions SO PLANETARY AND SPACE SCIENCE LA English DT Article DE lunar dust; dust charging; photoelectric emission; photoelectric yield; lunar dust levitation ID IONIZATION-POTENTIALS; INTERSTELLAR DUST; SILVER PARTICLES; METAL-CLUSTERS; WORK FUNCTION; GRAINS; ENERGY; GAS; PHOTOEMISSION; RADIATION AB The lunar surface is covered with a thick layer of sub-micron/micron size dust grains formed by meteoritic impact over billions of years. The fine dust grains are levitated and transported on the lunar surface, as indicated by the transient dust clouds observed over the lunar horizon during the Apollo 17 mission. Theoretical models suggest that the dust grains on the lunar surface are charged by the solar ultraviolet (UV) radiation as well as the solar wind. Even without any physical activity, the dust grains are levitated by electrostatic fields and transported away from the surface in the near vacuum environment of the Moon. The current dust charging and levitation models, however, do not fully explain the observed phenomena. Since the abundance of dust on the Moon's surface with its observed adhesive characteristics has the potential of severe impact on human habitat and operations and lifetime of a variety of equipment, it is necessary to investigate the charging properties and the lunar dust phenomena in order to develop appropriate mitigating strategies. Photoelectric emission induced by the solar UV radiation with photon energies higher than the work function (WF) of the grain materials is recognized to be the dominant process for charging of the lunar dust, and requires measurements of the photoelectric yields to determine the charging and equilibrium potentials of individual dust grains. In this paper, we present the first laboratory measurements of the photoelectric efficiencies and yields of individual sub-micron/micron size dust grains selected from sample returns of Apollo 17 and Luna-24 missions as well as similar size dust grains from the JSC-1 simulants. The measurements were made on a laboratory facility based on an electrodynamic balance that permits a variety of experiments to be conducted on individual sub-micron/ micron size dust grains in simulated space environments. The photoelectric emission measurements indicate grain size dependence with the yield increasing by an order of magnitude for grains of sub-micron to several micron size radii, at which it reaches asymptotic values. The yield for large size grains is found to be more than an order of magnitude higher than the bulk measurements on lunar fines reported in the literature. (c) 2007 Elsevier Ltd. All rights reserved. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Huntsville, AL 35899 USA. RP Abbas, MM (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM Mian.M.Abbas@nasa.gov NR 48 TC 27 Z9 32 U1 0 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD MAY PY 2007 VL 55 IS 7-8 BP 953 EP 965 DI 10.1016/j.pss.2006.12.007 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 175MQ UT WOS:000247018100009 ER PT J AU Goebel, JH AF Goebel, John H. TI Gravity Probe B photometry and observations of zeta Pegasi: An SPB variable star SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID CD-ROM; READOUT ELECTRONICS; BINARY STARS; CATALOG; TELESCOPE; MISSION AB The Gravity Probe B (GP-B) satellite photometric system and instrumentation are introduced. Observational results are presented for calibration stars demonstrating a single-orbit relative photometric precision capability of 500 mu mag for bright stars. Broadband photometric observations of the bright star zeta Pegasi are then presented that display brightness variability of 488.2 +/- 6.6 mu mag (parts per million), with a period of 22.952 +/- 0.804 hr (f approximate to 1.04566 cycles day(-1)). Over the short observational period, the variation is monosinusoidal, thus recommending the star for membership in the class of small-amplitude, slowly pulsating B (SPB) star variables oscillating in a nonradial g-mode. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Stanford Univ, HEPL, Stanford, CA 94305 USA. RP Goebel, JH (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM goebel@relgyro.stanford.edu NR 24 TC 1 Z9 2 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD MAY PY 2007 VL 119 IS 855 BP 483 EP 493 DI 10.1086/518618 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 173WM UT WOS:000246903200002 ER PT J AU Dixon, WV Sahnow, DJ Barrett, PE Civeit, T Dupuis, J Fullerton, AW Godard, B Hsu, JC Kaiser, ME Kruk, JW Lacour, S Lindler, DJ Massa, D Robinson, RD Romelfanger, ML Sonnentrucker, P AF Dixon, W. V. Sahnow, D. J. Barrett, P. E. Civeit, T. Dupuis, J. Fullerton, A. W. Godard, B. Hsu, J.-C. Kaiser, M. E. Kruk, J. W. Lacour, S. Lindler, D. J. Massa, D. Robinson, R. D. Romelfanger, M. L. Sonnentrucker, P. TI CalFUSE version 3: A data reduction pipeline for the Far Ultraviolet Spectroscopic Explorer SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID PERFORMANCE; DETECTORS; G191-B2B; STARS AB Since its launch in 1999, the Far Ultraviolet Spectroscopic Explorer (FUSE) has made over 4900 observations of some 2500 individual targets. The data are reduced by the principal investigator team at the Johns Hopkins University and archived at the Multimission Archive at STScI (MAST). The data reduction software package, called CalFUSE, has evolved considerably over the lifetime of the mission. The entire FUSE data set has recently been reprocessed with CalFUSE version 3.2, the latest version of this software. This paper describes CalFUSE version 3.2, the instrument calibrations on which it is based, and the format of the resulting calibrated data files. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Space Telescope Sci Inst, ESS, SSG, Baltimore, MD 21218 USA. Ctr Natl Etud Spatiales, Paris, France. Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 2Y2, Canada. Sigma Space Corp, Lanham, MD USA. NASA, Goddard Space Flight Ctr, SGT Inc, Greenbelt, MD 20771 USA. RP Dixon, WV (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. EM wvd@pha.jhu.edu RI Kruk, Jeffrey/G-4047-2012 NR 19 TC 84 Z9 84 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD MAY PY 2007 VL 119 IS 855 BP 527 EP 555 DI 10.1086/518617 PG 29 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 173WM UT WOS:000246903200007 ER PT J AU Bivolaru, D Herring, GC AF Bivolaru, Daniel Herring, G. C. TI Focal-plane imaging of crossed beams in nonlinear optics experiments SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID SCATTERING AB An application of focal-plane imaging that can be used as a real time diagnostic of beam crossing in various optical techniques is reported. We discuss two specific versions and demonstrate the capability of maximizing system performance with an example in a combined dual-pump coherent anti-Stokes Raman scattering-interferometric Rayleigh scattering experiment (CARS-IRS). We find that this imaging diagnostic significantly reduces beam alignment time and loss of CARS-IRS signals due to inadvertent misalignments. (C) 2007 American Institute of Physics. C1 NASA, Langley Res Ctr, Adv Sensing & Opt Measurement Branch, Hampton, VA 23681 USA. RP Bivolaru, D (reprint author), NASA, Langley Res Ctr, Adv Sensing & Opt Measurement Branch, 18 Langley Blvd, Hampton, VA 23681 USA. NR 7 TC 9 Z9 9 U1 1 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 2007 VL 78 IS 5 AR 056102 DI 10.1063/1.2735581 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 173SP UT WOS:000246893100061 PM 17552864 ER PT J AU Wu, CC Lepping, RP AF Wu, Chin-Chun Lepping, R. P. TI Comparison of the characteristics of magnetic clouds and magnetic cloud-like structures for the events of 1995-2003 SO SOLAR PHYSICS LA English DT Article DE magnetic cloud; solar cycle; solar wind ID GEOMAGNETIC STORMS; SOLAR-CYCLE; WIND; CMES AB Using nine years of solar wind plasma and magnetic field data from the Wind mission, we investigated the characteristics of both magnetic clouds (MCs) and magnetic cloud-like structures (MCLs) during 1995-2003. A MCL structure is an event that is identified by an automatic scheme (Lepping, Wu, and Berdichevsky, Ann. Geophys. 23, 2687, 2005) with the same criteria as for a MC, but it is not usually identifiable as a flux rope by using the MC (Burlaga et al., J. Geophys. Res. 86, 6673, 1981) fitting model developed by Lepping, Jones, and Burlaga (Geophys. Res. Lett. 95(11), 957, 1990). The average occurrence rate is 9.5 for MCs and 13.6 for MCLs per year for the overall period of interest, and there were 82 MCs and 122 MCLs identified during this period. The characteristics of MCs and MCL structures are as follows: (1) The average duration, Delta t, of MCs is 21.1 h, which is 40% longer than that for MCLs (Delta t = 15 h); (2) the average B-zmin (minimum B-z found in MC/MCL measured in geocentric solar ecliptic coordinates) is -10.2 nT for MCs and -6 nT for MCLs; (3) the average Dst(min) (minimum Dst caused by MCs/MCLs) is -82 nT for MCs and -37 nT for MCLs; (4) the average solar wind velocity is 453 km s(-1) for MCs and 413 km s(-1) for MCLs; (5) the average thermal speed is 24.6 kms(-1) for MCs and 27.7 kms(-1) for MCLs; (6) the average magnetic field intensity is 12.7 nT for MCs and 9.8 nT for MCLs; (7) the average solar wind density is 9.4 cm(-3) for MCs and 6.3 cm(-3) for MCLs; and (8) a MC is one of the most important interplanetary structures capable of causing severe geomagnetic storms. The longer duration, more intense magnetic field and higher solar wind speed of MCs, compared to those properties of the MCLs, are very likely the major reasons for MCs generally causing more severe geomagnetic storms than MCLs. But the fact that a MC is an important interplanetary structure with respect to geomagnetic storms is not new (e.g., Zhang and Burlaga, J. Geophys. Res. 93, 2511, 1988; Bothmer, SP- 535, 419, 2003). C1 Univ Alabama, CSPAR, Huntsville, AL 35899 USA. Chinese Acad Sci, Key State Lab Space Weather, Beijing 100080, Peoples R China. NASA, Goddard Space Flight Ctr, Heliophys Sci Div, Greenbelt, MD 20771 USA. RP Wu, CC (reprint author), Univ Alabama, CSPAR, Huntsville, AL 35899 USA. EM wuc@cspar.uah.edu NR 17 TC 18 Z9 19 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD MAY PY 2007 VL 242 IS 1-2 BP 159 EP 165 DI 10.1007/s11207-007-0323-6 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 191ND UT WOS:000248137000012 ER PT J AU Davila, J Gopalswamy, N Haubold, HJ Thompson, B AF Davila, Joe Gopalswamy, Nat Haubold, Hans J. Thompson, Barbara TI International Heliophysical Year 2007: Basic space science initiatives SO SPACE POLICY LA English DT Editorial Material ID EDUCATION; CLIMATE AB The UN Office for Outer Space Affairs, through the MY Secretariat and the United Nations Basic Space Science Initiative (UNBSSI), assists scientists and engineers world-wide to participate in the International Heliophysical Year (IHY) 2007. A major thrust of IHY/UNBSSI is to deploy arrays of small, inexpensive instruments such as magnetometers, radio telescopes, GPS receivers, all-sky cameras, etc. around the world to allow global measurements of ionospheric and heliospheric phenomena. The small instrument program is envisioned as a partnership between instrument providers and instrument hosts in developing nations, with the former providing the instruments, the host nation the manpower, facilities and operational support, typically at a local university. Funds are not available through IHY/UNBSSI to build the instruments; these must be obtained through the normal proposal channels. All instrument operational support for local scientists, facilities, data acquisition, etc. will be provided by the host nation. The IHY/UNBSSI can facilitate the deployment of several of these networks and existing databases and relevant software tools will be identified to promote space science activities in developing nations. Extensive data on space science have been accumulated by a number of space missions. Similarly, long-term databases are available from ground-based observations. These data can be utilized in ways different from those originally intended for understanding the heliophysical processes. This report provides an overview of IHY/UNBSSL its achievements, future plans and outreach to the 192 member states of the United Nations. (C) 2007 Elsevier Ltd. All rights reserved. C1 Vienna Int Ctr, UN Off Outer Space Affairs, A-1400 Vienna, Austria. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Haubold, HJ (reprint author), Vienna Int Ctr, UN Off Outer Space Affairs, A-1400 Vienna, Austria. EM hans.haubold@unvienna.org OI Gopalswamy, Nat/0000-0001-5894-9954 NR 25 TC 2 Z9 3 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0265-9646 J9 SPACE POLICY JI Space Policy PD MAY PY 2007 VL 23 IS 2 BP 121 EP 126 DI 10.1016/j.spacepol.2007.02.015 PG 6 WC International Relations; Social Sciences, Interdisciplinary SC International Relations; Social Sciences - Other Topics GA 176MP UT WOS:000247089700008 ER PT J AU Bozzolo, G Garces, JE Derry, GN AF Bozzolo, Guillermo Garces, Jorge E. Derry, Gregory N. TI Atomistic modeling of segregation and bulk ordering in Ag-Au alloys SO SURFACE SCIENCE LA English DT Article DE silver; gold; surface segregation; computer simulations; Monte Carlo simulations ID AUGER-ELECTRON SPECTROSCOPY; LOW-INDEX FACES; SURFACE; DEPOSITION; SYSTEMS; AL; CU AB The bulk and surface properties of Ag-Au alloys, for the whole range of concentration and as a function of temperature, is studied by means of a simple modeling scheme using the Bozzolo-Ferrante-Smith method for alloys. Evidence for short-range order is found and explained, as well as its relationship with the experimentally observed segregation behavior. (c) 2007 Elsevier B.V. All rights reserved. C1 Ohio Aerosp Inst, Cleveland, OH USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Comis Nacl Energia Atom, Ctr Atom Bariloche, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina. Loyola Coll, Dept Phys, Baltimore, MD 21210 USA. RP Bozzolo, G (reprint author), Ohio Aerosp Inst, 22800 Cedar Point Rd, Cleveland, OH USA. EM Guillermo.H.Bozzolo@grc.nasa.gov NR 19 TC 12 Z9 12 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 1 PY 2007 VL 601 IS 9 BP 2038 EP 2046 DI 10.1016/j.susc.2007.02.035 PG 9 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 168UU UT WOS:000246550300019 ER PT J AU Thacker, WD Sarkar, S Gatski, TB AF Thacker, W. D. Sarkar, S. Gatski, T. B. TI Analyzing the influence of compressibility on the rapid pressure-strain rate correlation in turbulent shear flows SO THEORETICAL AND COMPUTATIONAL FLUID DYNAMICS LA English DT Article DE compressible turbulence; turbulence theory; supersonic shear flows ID DIRECT-NUMERICAL-SIMULATION; DISTORTION-THEORY; MIXING LAYER; ANISOTROPIC TURBULENCE; GREENS-FUNCTIONS; BOUNDARY-LAYER; CHANNEL FLOW; DIRECT WAVES; GROWTH-RATE; SPECTRUM AB The influence of compressibility on the rapid pressure-strain rate tensor is investigated using the Green's function for the wave equation governing pressure fluctuations in compressible homogeneous shear flow. The solution for the Green's function is obtained as a combination of parabolic cylinder functions; it is oscillatory with monotonically increasing frequency and decreasing amplitude at large times, and anisotropic in wave-vector space. The Green's function depends explicitly on the turbulent Mach number M (t) , given by the root mean square turbulent velocity fluctuations divided by the speed of sound, and the gradient Mach number M (g) , which is the mean shear rate times the transverse integral scale of the turbulence divided by the speed of sound. Assuming a form for the temporal decorrelation of velocity fluctuations brought about by the turbulence, the rapid pressure-strain rate tensor is expressed exactly in terms of the energy (or Reynolds stress) spectrum tensor and the time integral of the Green's function times a decaying exponential. A model for the energy spectrum tensor linear in Reynolds stress anisotropies and in mean shear is assumed for closure. The expression for the rapid pressure-strain correlation is evaluated using parameters applicable to a mixing layer and a boundary layer. It is found that for the same range of M (t) there is a large reduction of the pressure-strain correlation in the mixing layer but not in the boundary layer. Implications for compressible turbulence modeling are also explored. C1 Univ Calif San Diego, Dept Mech & Aerosp Engn, La Jolla, CA 92093 USA. St Louis Univ, Dept Phys, St Louis, MO 63103 USA. St Louis Univ, Ctr Fluids All Scales, St Louis, MO 63103 USA. NASA, Langley Res Ctr, Computat Aerosci Branch, Hampton, VA USA. Old Dominion Univ, Ctr Coastal Phys Oceanog & Ocean Earth & Atmosphe, Norfolk, VA 23529 USA. RP Sarkar, S (reprint author), Univ Calif San Diego, Dept Mech & Aerosp Engn, La Jolla, CA 92093 USA. EM sarkar@ucsd.edu NR 39 TC 9 Z9 9 U1 0 U2 9 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0935-4964 J9 THEOR COMP FLUID DYN JI Theor. Comput. Fluid Dyn. PD MAY PY 2007 VL 21 IS 3 BP 171 EP 199 DI 10.1007/s00162-007-0043-4 PG 29 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 159GK UT WOS:000245853200002 ER PT J AU Berejikian, BA Endicott, RC Van Doornik, DM Brown, RS Tatara, CP Atkins, J AF Berejikian, Barry A. Endicott, Robert C. Van Doornik, Donald M. Brown, Richard S. Tatara, Christopher P. Atkins, Jeffery TI Spawning by female Chinook salmon can be detected by electromyogram telemetry SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID CROSS-SPECIES AMPLIFICATION; ONCORHYNCHUS-TSHAWYTSCHA; REPRODUCTIVE SUCCESS; NATURAL-POPULATIONS; MICROSATELLITE LOCI; SOCKEYE-SALMON; PACIFIC SALMON; LAKE TROUT; SALAR L.; BEHAVIOR AB New methods to detect spawning of anadromous salmonids in their natural environment are needed to improve understanding of breeding behavior patterns, natural selection on reproductive traits (e.g., spawn timing), and interactions between artificially propagated and wild fish. We implanted maturing female Chinook salmon Oncorhynchus tshawytscha with coded electromyogram (CEMG) transmitters and continuously recorded spawning activity to develop an algorithm capable of accurately detecting spawning events from CEMG data. Marked increases in female digging frequencies immediately after spawning (cover digging) strongly correlated with CEMG values. The algorithm detected averages of 65% and 86% of the actual spawning events in 2003 and 2004, respectively. The algorithm accurately detected zero spawning events for the two female salmon that did not spawn. The presence of CEMG transmitters did not affect the digging frequency, number of nests constructed, or the reproductive life span of implanted fish. However, the CEMG tagging procedure or the presence of tags significantly increased egg retention. Pedigree analyses of DNA confirmed that females implanted with CEMG transmitters exhibited significantly lower individual reproductive success relative to that of nontagged females (73% and 66% reduction in two separate experiments). Subsequent research in adult steelhead O. mykiss has indicated that alternative implantation techniques hold promise for reducing the effects of the tags on reproductive success. We suggest that remote monitoring of salmonid spawning behavior is now possible with CEMG technology and should be tested in natural habitats. C1 NW Fisheries Sci Ctr, Natl Marine Fisheries Serv, Resource Enhancement & Utilizat Technol Div, Manchester, WA 98353 USA. NW Fisheries Sci Ctr, Natl Marine Fisheries Serv, Conservat Biol Div, Seattle, WA 98112 USA. RP Berejikian, BA (reprint author), NW Fisheries Sci Ctr, Natl Marine Fisheries Serv, Resource Enhancement & Utilizat Technol Div, Manchester Res Stn,Post Off Box 130, Manchester, WA 98353 USA. EM barry.berejikian@noaa.gov NR 36 TC 7 Z9 7 U1 0 U2 7 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD MAY PY 2007 VL 136 IS 3 BP 593 EP 605 DI 10.1577/T06-114.1 PG 13 WC Fisheries SC Fisheries GA 175DK UT WOS:000246992600005 ER PT J AU DellaCorte, C AF DellaCorte, Christopher TI Introducing TLT's new editor SO TRIBOLOGY & LUBRICATION TECHNOLOGY LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP DellaCorte, C (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM cdellacorte@stle.org NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 1545-858X J9 TRIBOL LUBR TECHNOL JI Tribol. Lubr. Technol. PD MAY PY 2007 VL 63 IS 5 BP 6 EP 6 PG 1 WC Engineering, Mechanical SC Engineering GA 163XV UT WOS:000246197500002 ER PT J AU Sun, XH Yu, B Meyyappan, M AF Sun, Xuhui Yu, Bin Meyyappan, M. TI Synthesis and nanoscale thermal encoding of phase-change nanowires SO APPLIED PHYSICS LETTERS LA English DT Article ID THIN-FILMS; MEMORY; SILICON; STORAGE; MEDIA AB Low-dimensional phase-change nanostructures provide a valuable research platform for understanding the phase-transition behavior and thermal properties at nanoscale and their potential in achieving superdense data storage. Ge2Sb2Te5 nanowires have been grown using a vapor-liquid-solid technique and shown to exhibit distinctive properties that may overcome the present data storage scaling barrier. Local heating of an individual nanowire with a focused electron beam was used to shape a nano-bar-code on a Ge2Sb2Te5 nanowire. The data encoding on Ge2Sb2Te5 nanowire may promote novel device concepts to implement ultrahigh density, low energy, high speed data storage using phase-change nanomaterials with diverse thermal-programing strategies. (c) 2007 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Sun, XH (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM xsun@arc.nasa.gov; byu@arc.nasa.gov RI Sun, Xuhui /K-5689-2012 NR 22 TC 29 Z9 29 U1 0 U2 12 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 30 PY 2007 VL 90 IS 18 AR 183116 DI 10.1063/1.2736271 PG 3 WC Physics, Applied SC Physics GA 164CK UT WOS:000246210000118 ER PT J AU Yamaguchi, KE Johnson, CM Beard, BL Beukes, NJ Gutzmer, J Ohmoto, H AF Yamaguchi, Kosel E. Johnson, Clark M. Beard, Brian L. Beukes, Nicolas J. Gutzmer, Jens Ohmoto, Hiroshi TI Isotopic evidence for iron mobilization during Paleoproterozoic lateritization of the Hekpoort paleosol profile from Gaborone, Botswana SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE paleosol; Fe; isotope; weathering ID BILLION YEARS AGO; GREAT OXIDATION EVENT; MC-ICP-MS; SOUTH-AFRICA; ATMOSPHERIC OXYGEN; GRIQUALAND WEST; FE ISOTOPES; OXIDE REDUCTION; SOIL FORMATION; FRACTIONATION AB The isotopic composition and elemental abundance of Fe in a lateritic weathering profile (drillcore Strata-1) formed on the similar to 2.2 Ga Hekpoort basalt of the Pretoria Group in Gaborone, Botswana, document open-system behavior for Fe during paleosol formation. The delta(56) Fe values of the profile increase from similar to 0 parts per thousand at the bottom (parental basalt) to +1 parts per thousand in the mid-depth mottled (Fe-depleted) zone, then decrease to +0.3 parts per thousand at the top of the laterite (Fe-enriched) zone. The reworked ferricrete and red beds that overlie the laterite have high delta Fe-56 values of +0.2 to +0.4 parts per thousand, which are comparable to those of the underlying laterite. Because of the absence of a complementary low-delta 56(Fe) zone, these results are not compatible with a model of simple internal redistribution (closed-system) of Fe within the paleosol column. Instead, these results are well explained through fluid-rock interaction involving transport of aqueous Fe2+ through the system during paleosol evolution. Production of positive delta Fe-56 values for Fe3+ oxides were simulated through oxidation of low-delta Fe-56 Fe-aq(2+) using experimentally determined Fe-oxide(3+)-Fe-aq(2+) fractionation factors. The increased quantities of Fe involved in formation of the Hekpoort paleosol relative to previous estimates based on a closed-system model require a commensurate increase in the abundance of an oxidant, such as atmospheric O-2, to explain the Fe3+/Fe2+ ratios in the paleosol. Therefore, previous estimates of atmospheric O-2 levels of 2.5 x 10(-4) to 9 x 10(-3) atm based on this section [W. Yang, H.D. Holland, The Hekpoort paleosol profile in Strata 1 at Gaborone, Botswana: Soil formation during the great oxidation event, American Journal of Science 303(2003) 187-220] are too low by an order of magnitude or more. These results demonstrate that Fe isotopes can provide important constraints on open-versus closed-system behavior of Fe in ancient weathering profiles, a distinction that is critical when calculating Fe mobility as a means for inferring surface redox conditions in the past. (C) 2007 Elsevier B.V. All rights reserved. C1 JAMSTEC, Inst Res earth Evolut IFREE, Kanagawa 2370061, Japan. Univ Wisconsin, Dept Geol & Geophys, Madison, WI 53706 USA. NASA, Astrobiol Inst, Washington, DC USA. Univ Johannesburg, Dept Geol, ZA-2006 Johannesburg, South Africa. Penn State Univ, Astrobiol Res Ctr, University Pk, PA 16802 USA. Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. RP Yamaguchi, KE (reprint author), JAMSTEC, Inst Res earth Evolut IFREE, 2-15 Natsushima, Kanagawa 2370061, Japan. EM kosei@jamstec.go.jp NR 52 TC 21 Z9 21 U1 2 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD APR 30 PY 2007 VL 256 IS 3-4 BP 577 EP 587 DI 10.1016/j.epsl.2007.02.010 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 176CU UT WOS:000247061300022 ER PT J AU Li, QL Chen, JQ Song, B LaCroix, JJ Bresee, MK Radmacher, JA AF Li, Qinglin Chen, Jiquan Song, Bo LaCroix, Jacob J. Bresee, Mary K. Radmacher, John A. TI Areas influenced by multiple edges and their implications in fragmented landscapes SO FOREST ECOLOGY AND MANAGEMENT LA English DT Article DE edge effects; area of multiple edge influences (AMEI); depth of edge influences (DEI); fragmentation; landscape analysis ID DOUGLAS-FIR FORESTS; MANAGED LANDSCAPE; HABITAT FRAGMENTATION; BUDWORM DEFOLIATION; NORTHERN WISCONSIN; PATTERNS; CONSEQUENCES; CONSERVATION; COMMUNITIES; GRADIENTS AB We introduced a new approach for delineating areas of multiple edge influence (AMEI) within a fragmented landscape using a geographic information system (GIs). AMEI was defined as the interface that is affected by more than two neighboring patch types. We decomposed AMEI into three components: AMEI(1), the area where one patch type meets a different patch type; AMEI(2), the area where one patch type meets two different patch types; AMEI(3), the area where one patch type meets three or more other different patch types. This approach provides a direct measure of the complexities of multiple edge effects that may occur at a spatial location, and also measures the amount of the affected area at the patch and landscape levels. Using the Chequamegon National Forest (CNF), USA, as a case study, we found that the total AMEI was approximately 48, 74, 86, and 92% of the landscape with depth of edge influence (DEI) at 30, 60, 90, and 120 m, respectively. The more complicated components of the area of multiple edge influence (AMEI(2) and AMEI(3)) ranged from 5% (at 30 m DEI) to 60% (at 120 m DEI) of the studied landscape. Most empirical and modeling studies miss this additional edge complexity if they only consider a single edge structure. In general, AMEI(1) is greater than AMEI(2); AMEI(2) is greater than AMEI(3). Three indices - AMEI to patch area ratio (APAR), AMEI to patch edge area ratio (APEAR), and AMEI to landscape area ratio (ALAR) - were introduced to explain the relative importance of AMEI at the edge, patch, and landscape levels. This approach has the potential to improve model predictions and better inform us about ecological processes that are influenced by multiple edge effects at patch and landscape scales. (C) 2006 Elsevier B.V. All rights reserved. C1 Timberline Nat Resource Grp Ltd, Kelowna, BC V1Y 4R1, Canada. Univ Toledo, Dept Environm Sci, Toledo, OH 43606 USA. Clemson Univ, Belle W Baruch Inst Coastal Ecol & Forest Sci, Georgetown, SC 29442 USA. Natl Marine Fisheries Serv, Auke Bay Labs, Juneau, AK 99801 USA. RP Li, QL (reprint author), Timberline Nat Resource Grp Ltd, 1884 Spall Rd 214, Kelowna, BC V1Y 4R1, Canada. EM geoliqinglin@yahoo.com RI Chen, Jiquan/D-1955-2009 NR 39 TC 10 Z9 10 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-1127 EI 1872-7042 J9 FOREST ECOL MANAG JI For. Ecol. Manage. PD APR 30 PY 2007 VL 242 IS 2-3 BP 99 EP 107 DI 10.1016/j.foreco.2006.11.022 PG 9 WC Forestry SC Forestry GA 164XL UT WOS:000246268100002 ER PT J AU Hu, YX Vaughan, M Liu, ZY Lin, B Yang, P Flittner, D Hunt, B Kuehn, R Huang, JP Wu, D Rodier, S Powell, K Trepte, C Winker, D AF Hu, Yongxiang Vaughan, Mark Liu, Zhaoyan Lin, Bing Yang, Ping Flittner, David Hunt, Bill Kuehn, Ralph Huang, Jianping Wu, Dong Rodier, Sharon Powell, Kathy Trepte, Charles Winker, David TI The depolarization - attenuated backscatter relation: CALIPSO lidar measurements vs. theory SO OPTICS EXPRESS LA English DT Article ID MULTIPLE-SCATTERING; WATER CLOUDS; EXTINCTION; PHASE AB Using measurements obtained by the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite, relationships between layer-integrated depolarization ratio (delta) and layer-integrated attenuated backscatter (gamma') are established for moderately thick clouds of both ice and water. A new and simple form of the delta-gamma' relation for spherical particles, developed from Monte Carlo simulations and suitable for both water clouds and spherical aerosol particles, is found to agree well with the observations. A high-backscatter, low-depolarization delta-gamma' relationship observed for some ice clouds is shown to result primarily from horizontally oriented plates and implies a preferential lidar ratio - depolarization ratio relation in nature for ice cloud particles containing plates. (C) 2007 Optical Society of America. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. RP Hu, YX (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM Yongxiang.hu-1@nasa.gov RI Liu, Zhaoyan/A-9604-2009; Liu, Zhaoyan/B-1783-2010; Yang, Ping/B-4590-2011; Hu, Yongxiang/K-4426-2012 OI Liu, Zhaoyan/0000-0003-4996-5738; NR 10 TC 87 Z9 96 U1 1 U2 17 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD APR 30 PY 2007 VL 15 IS 9 BP 5327 EP 5332 DI 10.1364/OE.15.005327 PG 6 WC Optics SC Optics GA 166QU UT WOS:000246395000007 PM 19532786 ER PT J AU Ilchenko, VS Mohageg, M Savchenkov, AA Matsko, AB Maleki, L AF Ilchenko, Vladimir S. Mohageg, Makan Savchenkov, Anatoliy A. Matsko, Andrey B. Maleki, Lute TI Efficient generation of truncated Bessel beams using cylindrical waveguides SO OPTICS EXPRESS LA English DT Article ID DIFFRACTION-FREE BEAMS; AXICON; RESONATOR; MODES; LASER; HOLOGRAMS; MOMENTUM; FIELDS AB In this paper we address efficient conversion between a Gaussian beam (a truncated plane wave) and a truncated Bessel beam of a given order, using cylindrical optical waveguides and whispering gallery mode resonators. Utilizing a generator based on waveguides combined with whispering gallery mode resonators, we have realized Bessel beams of the order of 200 with a conversion efficiency exceeding 10%. (c) 2007 Optical Society of America C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ilchenko, VS (reprint author), CALTECH, Jet Prop Lab, MS 298-100,48 Oak Grove Dr, Pasadena, CA 91109 USA. EM Andrey.Matsko@jpl.nasa.gov RI Matsko, Andrey/A-1272-2007 NR 31 TC 12 Z9 12 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD APR 30 PY 2007 VL 15 IS 9 BP 5866 EP 5871 DI 10.1364/OE.15.005866 PG 6 WC Optics SC Optics GA 166QU UT WOS:000246395000066 PM 19532845 ER PT J AU Araneda, JA Marsch, E Vinas, AF AF Araneda, J. A. Marsch, E. Vinas, A. F. TI Collisionless damping of parametrically unstable Alfven waves SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID FINITE-AMPLITUDE; MODULATIONAL INSTABILITY; DECAY INSTABILITIES; MAGNETIC-FIELD; BETA PLASMA; SOLAR-WIND; PARALLEL; EXCITATION; FLUCTUATIONS; SIMULATIONS AB [1] Linear Vlasov theory and one-dimensional hybrid simulations are used to study the parametric instabilities of a circularly polarized parallel propagating Alfven wave in a homogeneous, magnetized, and collisionless plasma. We discuss the linear and the weakly nonlinear development of the instabilities of the Alfven waves, including kinetic effects, and investigate the structure, the growth, and the damping of the driven ion acoustic-like waves. The dispersion relation reproduces the fluid characteristics of the instabilities in the case that protons are cold but contains an infinite number of roots in the general case. We show that at low proton plasma beta(p) (beta(p) approximate to 0.1), kinetic effects break the degeneracy of the mode-coupling solutions of the fluid theory, and we unambiguously identify the growing and the damped modes. We find that contrary to traditional thought, kinetic effects are important even for very low-beta(p) in the late stages of the linear evolution, leading to a dephasing effect between the plasma pressure and the density fluctuations. The relevance of the results to the experimental identification of the instabilities, to the generation of local turbulence, and to the reduction of cross helicity in the solar wind are pointed out. C1 Univ Concepcion, Dept Fis, Fac Ciencias Fis & Matemat, Concepcion, Chile. Max Planck Inst Sonnensystemforsch, D-37191 Katlenburg Lindau, Germany. NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Heliospher Phys Branch, Greenbelt, MD 20771 USA. RP Araneda, JA (reprint author), Univ Concepcion, Dept Fis, Fac Ciencias Fis & Matemat, Casilla 160-C, Concepcion, Chile. EM jaraneda@udec.cl; marsch@linmpi.mpg.de; adolfo.vinas@gsfc.nasa.gov RI Araneda, Jaime/J-9245-2015 NR 44 TC 31 Z9 32 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 28 PY 2007 VL 112 IS A4 AR A04104 DI 10.1029/2006JA011999 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 163GB UT WOS:000246145800004 ER PT J AU Proshutinsky, A Ashik, I Hakkinen, S Hunke, E Krishfield, R Maltrud, M Maslowski, W Zhang, J AF Proshutinsky, A. Ashik, I. Haekkinen, S. Hunke, E. Krishfield, R. Maltrud, M. Maslowski, W. Zhang, J. TI Sea level variability in the Arctic Ocean from AOMIP models SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID LAPTEV SEA; FAST-ICE; NUMERICAL-MODEL; WIND; CIRCULATION; REGIMES; CLIMATE; SHELF; PARAMETERIZATION; PRESSURE AB [1] Monthly sea levels from five Arctic Ocean Model Intercomparison Project ( AOMIP) models are analyzed and validated against observations in the Arctic Ocean. The AOMIP models are able to simulate variability of sea level reasonably well, but several improvements are needed to reduce model errors. It is suggested that the models will improve if their domains have a minimum depth less than 10 m. It is also recommended to take into account forcing associated with atmospheric loading, fast ice, and volume water fluxes representing Bering Strait inflow and river runoff. Several aspects of sea level variability in the Arctic Ocean are investigated based on updated observed sea level time series. The observed rate of sea level rise corrected for the glacial isostatic adjustment at 9 stations in the Kara, Laptev, and East Siberian seas for 1954 - 2006 is estimated as 0.250 cm/yr. There is a well pronounced decadal variability in the observed sea level time series. The 5-year running mean sea level signal correlates well with the annual Arctic Oscillation (AO) index and the sea level atmospheric pressure (SLP) at coastal stations and the North Pole. For 1954 - 2000 all model results reflect this correlation very well, indicating that the long-term model forcing and model reaction to the forcing are correct. Consistent with the influences of AO-driven processes, the sea level in the Arctic Ocean dropped significantly after 1990 and increased after the circulation regime changed from cyclonic to anticyclonic in 1997. In contrast, from 2000 to 2006 the sea level rose despite the stabilization of the AO index at its lowest values after 2000. C1 Woods Hole Oceanog Inst, Dept Phys Oceanog, Woods Hole, MA 02543 USA. USN, Postgrad Sch, Dept Oceanog, Monterey, CA 93943 USA. Univ Washington, Polar Sci Ctr, Seattle, WA 98105 USA. Arctic & Antarctic Res Inst, St Petersburg 198095, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Proshutinsky, A (reprint author), Woods Hole Oceanog Inst, Dept Phys Oceanog, MS 29,360 Woods Hole Rd, Woods Hole, MA 02543 USA. EM aproshutinsky@whoi.edu RI Hakkinen, Sirpa/E-1461-2012 NR 66 TC 23 Z9 23 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9275 EI 2169-9291 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD APR 26 PY 2007 VL 112 IS C4 AR C04S08 DI 10.1029/2006JC003916 PG 25 WC Oceanography SC Oceanography GA 163FO UT WOS:000246144400005 ER PT J AU Clark, BC Arvidson, RE Gellert, R Morris, RV Ming, DW Richter, L Ruff, SW Michalski, JR Farrand, WH Yen, A Herkenhoff, KE Li, R Squyres, SW Schroder, C Klingelhofer, G Bell, JF AF Clark, B. C., III Arvidson, R. E. Gellert, R. Morris, R. V. Ming, D. W. Richter, L. Ruff, S. W. Michalski, J. R. Farrand, W. H. Yen, A. Herkenhoff, K. E. Li, R. Squyres, S. W. Schroeder, C. Klingelhoefer, G. Bell, J. F., III TI Evidence for montmorillonite or its compositional equivalent in Columbia Hills, Mars SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID THERMAL EMISSION SPECTROMETER; X-RAY SPECTROMETER; GUSEV CRATER; MARTIAN SURFACE; SPIRIT ROVER; MOSSBAUER SPECTROMETER; SPECTRAL EVIDENCE; CLAY-MINERALS; SOILS; ROCKS AB [1] During its exploration of the Columbia Hills, the Mars Exploration Rover "Spirit'' encountered several similar samples that are distinctly different from Martian meteorites and known Gusev crater soils, rocks, and sediments. Occurring in a variety of contexts and locations, these "Independence class'' samples are rough-textured, iron-poor ( equivalent FeO similar to 4 wt%), have high Al/Si ratios, and often contain unexpectedly high concentrations of one or more minor or trace elements ( including Cr, Ni, Cu, Sr, and Y). Apart from accessory minerals, the major component common to these samples has a compositional profile of major and minor elements which is similar to the smectite montmorillonite, implicating this mineral, or its compositional equivalent. Infrared thermal emission spectra do not indicate the presence of crystalline smectite. One of these samples was found spatially associated with a ferric sulfate-enriched soil horizon, possibly indicating a genetic relationship between these disparate types of materials. Compared to the nearby Wishstone and Watchtower class rocks, major aqueous alteration involving mineral dissolution and mobilization with consequent depletions of certain elements is implied for this setting and may be undetectable by remote sensing from orbit because of the small scale of the occurrences and obscuration by mantling with soil and dust. C1 Lockheed Martin Corp, Littleton, CO 80127 USA. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. Univ Guelph, Dept Phys, Guelph, ON N1G 2W1, Canada. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. DLR Inst Raumsimulat, Linder Hoehe, D-51170 Cologne, Germany. Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. Space Sci Inst, Boulder, CO 80301 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Ohio State Univ, Dept Civil & Environm Engn & Geodet Sci, Columbus, OH 43210 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Johannes Gutenberg Univ Mainz, Inst Anorgan & Analyt Chem, D-55099 Mainz, Germany. RP Clark, BC (reprint author), Lockheed Martin Corp, Littleton, CO 80127 USA. EM benton.c.clark@lmco.com RI Schroder, Christian/B-3870-2009 OI Schroder, Christian/0000-0002-7935-6039 NR 74 TC 40 Z9 40 U1 4 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 26 PY 2007 VL 112 IS E6 AR E06S01 DI 10.1029/2006JE002756 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 163FS UT WOS:000246144800001 ER PT J AU Farrand, WH Bell, JF Johnson, JR Jolliff, BL Knoll, AH McLennan, SM Squyres, SW Calvin, WM Grotzinger, JP Morris, RV Soderblom, J Thompson, SD Watters, WA Yen, AS AF Farrand, W. H. Bell, J. F., III Johnson, J. R. Jolliff, B. L. Knoll, A. H. McLennan, S. M. Squyres, S. W. Calvin, W. M. Grotzinger, J. P. Morris, R. V. Soderblom, J. Thompson, S. D. Watters, W. A. Yen, A. S. TI Visible and near-infrared multispectral analysis of rocks at Meridiani Planum, Mars, by the Mars Exploration Rover Opportunity SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID BURNS FORMATION; LANDING SITE; PATHFINDER; MINERALOGY; HEMATITE; SOILS; SPECTROMETER; CHEMISTRY; MOSSBAUER; IMAGER AB [ 1] Multispectral measurements in the visible and near infrared of rocks at Meridiani Planum by the Mars Exploration Rover Opportunity's Pancam are described. The Pancam multispectral data show that the outcrops of the Burns formation consist of two main spectral units which in stretched 673, 535, 432 nm color composites appear buff- and purple-colored. These units are referred to as the HFS and LFS spectral units based on higher and lower values of 482 to 535 nm slope. Spectral characteristics are consistent with the LFS outcrop consisting of less oxidized, and the HFS outcrop consisting of more oxidized, iron-bearing minerals. The LFS surfaces are not as common and appear, primarily, at the distal ends of outcrop layers and on steep, more massive surfaces, locations that are subject to greater eolian erosion. Consequently, the HFS surfaces are interpreted as a weathering rind. Further inherent spectral differences between layers and between different outcrop map units, both untouched and patches abraded by the rover's Rock Abrasion Tool, are also described. Comparisons of the spectral parameters of the Meridiani outcrop with a set of laboratory reflectance measurements of Fe3+ - bearing minerals show that the field of outcrop measurements plots near the fields of hematite, ferrihydrite, poorly crystalline goethite, and schwertmannite. Rind and fracture fill materials, observed intermittently at outcrop exposures, are intermediate in their spectral character between both the HFS and LFS spectral classes and other, less oxidized, surface materials ( basaltic sands, spherules, and cobbles). C1 Space Sci Inst, Boulder, CO 80301 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. Harvard Univ, Bot Museum, Cambridge, MA 02138 USA. SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. Univ Nevada, Dept Geol Sci, Reno, NV 89557 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Farrand, WH (reprint author), Space Sci Inst, Boulder, CO 80301 USA. RI Johnson, Jeffrey/F-3972-2015; OI Soderblom, Jason/0000-0003-3715-6407 NR 52 TC 38 Z9 38 U1 0 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 26 PY 2007 VL 112 IS E6 AR E05S02 DI 10.1029/2006JE002773 PG 28 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 163FS UT WOS:000246144800002 ER PT J AU Kinch, KM Sohl-Dickstein, J Bell, JF Johnson, JR Goetz, W Landis, GA AF Kinch, Kjartan M. Sohl-Dickstein, Jascha Bell, James F., III Johnson, Jeffrey R. Goetz, Walter Landis, Geoffrey A. TI Dust deposition on the Mars Exploration Rover Panoramic Camera (Pancam) calibration targets SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID MAGNETIC-PROPERTIES EXPERIMENTS; VISIBLE/NEAR-INFRARED SPECTRA; ATMOSPHERIC DUST; MARTIAN AEROSOLS; PHOTOMETRIC PROPERTIES; PHASE FUNCTION; WIND STREAKS; GUSEV CRATER; MGS TES; MU-M AB [1] The Panoramic Camera (Pancam) on the Mars Exploration Rover mission has acquired in excess of 20,000 images of the Pancam calibration targets on the rovers. Analysis of this data set allows estimates of the rate of deposition and removal of aeolian dust on both rovers. During the first 150 - 170 sols there was gradual dust accumulation on the rovers but no evidence for dust removal. After that time there is ample evidence for both dust removal and dust deposition on both rover decks. We analyze data from early in both rover missions using a diffusive reflectance mixing model. Assuming a dust settling rate proportional to the atmospheric optical depth, we derive spectra of optically thick layers of airfall dust that are consistent with spectra from dusty regions on the Martian surface. Airfall dust reflectance at the Opportunity site appears greater than at the Spirit site, consistent with other observations. We estimate the optical depth of dust deposited on the Spirit calibration target by sol 150 to be 0.44 +/- 0.13. For Opportunity the value was 0.39 +/- 0.12. Assuming 80% pore space, we estimate that the dust layer grew at a rate of one grain diameter per similar to 100 sols on the Spirit calibration target. On Opportunity the rate was one grain diameter per similar to 125 sols. These numbers are consistent with dust deposition rates observed by Mars Pathfinder taking into account the lower atmospheric dust optical depth during the Mars Pathfinder mission. C1 Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Max Planck Inst Sonnensyst Forsch, D-37191 Katlenburg Lindau, Germany. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Kinch, KM (reprint author), Cornell Univ, Dept Astron, 408 Space Sci Bldg, Ithaca, NY 14853 USA. EM kmk66@cornell.edu RI Johnson, Jeffrey/F-3972-2015; Kinch, Kjartan/C-5742-2015 OI Kinch, Kjartan/0000-0002-4629-8880 NR 60 TC 31 Z9 31 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 26 PY 2007 VL 112 IS E6 AR E06S03 DI 10.1029/2006JE002807 PG 21 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 163FS UT WOS:000246144800003 ER PT J AU Ewing, D George, WK Rogers, MM Moser, RD AF Ewing, D. George, W. K. Rogers, M. M. Moser, R. D. TI Two-point similarity in temporally evolving plane wakes SO JOURNAL OF FLUID MECHANICS LA English DT Article ID HIGH-REYNOLDS-NUMBER; HOMOGENEOUS ISOTROPIC TURBULENCE; SELF-SIMILARITY; LARGE EDDIES; FAR WAKE; DOWNSTREAM EVOLUTION; AXISYMMETRICAL WAKE; BOUNDARY-LAYER; PART 1; JET AB The governing equations for the two-point correlations of the turbulent fluctuating velocity in the temporally evolving wake were analysed to determine whether they could have equilibrium similarity solutions. It was found that these equations could have such solutions for a finite-Reynolds-number wake, where the two-point velocity correlations could be written as a product of a time-dependent scale and a function dependent only on similarity variables. It is therefore possible to collapse the two-point measures of all the scales of motions in the temporally evolving wake using a single set of similarity variables. As in an earlier single-point analysis, it was found that the governing equations for the equilibrium similarity solutions could not be reduced to a form that was independent of a growth-rate dependent parameter. Thus, there is not a single 'universal' solution that describes the state of the large-scale structures, so that the large-scale structures in the far field may depend on how the flow is generated. The predictions of the similarity analysis were compared to the data from two direct numerical simulations of the temporally evolving wakes examined previously. It was found that the two-point velocity spectra of these temporally evolving wakes collapsed reasonably well over the entire range of scales when they were scaled in the manner deduced from the equilibrium similarity analysis. Thus, actual flows do seem to evolve in a manner consistent with the equilibrium similarity solutions. C1 McMaster Univ, Dept Mech Engn, Hamilton, ON L8S 4L7, Canada. Chalmers, Dept Appl Mech, S-41296 Gothenburg, Sweden. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Texas, Dept Mech Engn, Austin, TX 78712 USA. Univ Texas, Inst Computat Engn & Sci, Univ Stn 1, Austin, TX 78712 USA. RP Ewing, D (reprint author), Queens Univ, Dept Mech & Mat Engn, Kingston, ON K7L 3N6, Canada. NR 46 TC 10 Z9 10 U1 0 U2 3 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD APR 25 PY 2007 VL 577 BP 287 EP 307 DI 10.1017/S0022112006003260 PG 21 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 165VB UT WOS:000246332900014 ER PT J AU Cook, PA Savage, NH Turquety, S Carver, GD O'Connor, FM Heckel, A Stewart, D Whalley, LK Parker, AE Schlager, H Singh, HB Avery, MA Sachse, GW Brune, W Richter, A Burrows, JP Purvis, R Lewis, AC Reeves, CE Monks, PS Levine, JG Pyle, JA AF Cook, Peter A. Savage, Nicholas H. Turquety, Solene Carver, Glenn D. O'Connor, Fiona M. Heckel, Andreas Stewart, David Whalley, Lisa K. Parker, Alex E. Schlager, Hans Singh, Hanwant B. Avery, Melody A. Sachse, Glen W. Brune, William Richter, Andreas Burrows, John P. Purvis, Ruth Lewis, Alastair C. Reeves, Claire E. Monks, Paul S. Levine, James G. Pyle, John A. TI Forest fire plumes over the North Atlantic: p-TOMCAT model simulations with aircraft and satellite measurements from the ITOP/ICARTT campaign SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPOSPHERE MOPITT INSTRUMENT; CHEMISTRY TRANSPORT MODEL; ATMOSPHERIC CHEMISTRY; MOZAIC DATA; OZONE; EMISSIONS; IMPACT; SCHEME; NO2; PARAMETERIZATION AB [ 1] Intercontinental Transport of Ozone and Precursors (ITOP) ( part of International Consortium for Atmospheric Research on Transport and Transformation (ICARTT)) was an intense research effort to measure long-range transport of pollution across the North Atlantic and its impact on O-3 production. During the aircraft campaign plumes were encountered containing large concentrations of CO plus other tracers and aerosols from forest fires in Alaska and Canada. A chemical transport model, p-TOMCAT, and new biomass burning emissions inventories are used to study the emissions long-range transport and their impact on the troposphere O-3 budget. The fire plume structure is modeled well over long distances until it encounters convection over Europe. The CO values within the simulated plumes closely match aircraft measurements near North America and over the Atlantic and have good agreement with MOPITT CO data. O-3 and NOx values were initially too great in the model plumes. However, by including additional vertical mixing of O-3 above the fires, and using a lower NO2/CO emission ratio (0.008) for boreal fires, O-3 concentrations are reduced closer to aircraft measurements, with NO2 closer to SCIAMACHY data. Too little PAN is produced within the simulated plumes, and our VOC scheme's simplicity may be another reason for O-3 and NOx model-data discrepancies. In the p-TOMCAT simulations the fire emissions lead to increased tropospheric O-3 over North America, the north Atlantic and western Europe from photochemical production and transport. The increased O-3 over the Northern Hemisphere in the simulations reaches a peak in July 2004 in the range 2.0 to 6.2 Tg over a baseline of about 150 Tg. C1 Univ Cambridge, Ctr Atmospher Sci, Dept Chem, Cambridge CB2 1EW, England. Univ Cambridge, Natl Environm Res Council Ctr Atmonsper Sci, Atmospher Chem Modelling Support Unit, Cambridge, England. Harvard Univ, Atmospher Chem Modeling Grp, Cambridge, MA USA. Univ Bremen, Inst Environm Phys, D-28359 Bremen, Germany. Univ E Anglia, Sch Environm Sci, Norwich NR4 7TJ, Norfolk, England. Univ Leeds, Sch Chem, Leeds LS2 9JT, W Yorkshire, England. Univ Leicester, Dept Chem, Leicester LE1 7RH, Leics, England. Deutsch Zentrum Luft & Raumfahrt, Inst Phys Atmosphaere, D-82230 Oberpfaffenhofen, Germany. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Facil Airborne Atmospher Measurements, Cranfield MK43 0AL, Beds, England. Univ York, Dept Chem, York YO10 5DD, N Yorkshire, England. RP Cook, PA (reprint author), Univ Cambridge, Ctr Atmospher Sci, Dept Chem, Cambridge CB2 1EW, England. EM john.pyle@atm.ch.cam.ac.uk RI Lewis, Alastair/A-6721-2008; Richter, Andreas/C-4971-2008; Stewart, Dave/G-7491-2012; Monks, Paul/H-6468-2016; Burrows, John/B-6199-2014; OI Lewis, Alastair/0000-0002-4075-3651; Richter, Andreas/0000-0003-3339-212X; Monks, Paul/0000-0001-9984-4390; Burrows, John/0000-0002-6821-5580; Savage, Nicholas/0000-0001-9391-5100 NR 50 TC 37 Z9 37 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 25 PY 2007 VL 112 IS D10 AR D10S43 DI 10.1029/2006JD007563 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 163FC UT WOS:000246143200002 ER PT J AU Tang, YH Carmichael, GR Thongboonchoo, N Chai, TF Horowitz, LW Pierce, RB Al-Saadi, JA Pfister, G Vukovich, JM Avery, MA Sachse, GW Ryerson, TB Holloway, JS Atlas, EL Flocke, FM Weber, RJ Huey, LG Dibb, JE Streets, DG Brune, WH AF Tang, Youhua Carmichael, Gregory R. Thongboonchoo, Narisara Chai, Tianfeng Horowitz, Larry W. Pierce, Robert B. Al-Saadi, Jassim A. Pfister, Gabriele Vukovich, Jeffrey M. Avery, Melody A. Sachse, Glen W. Ryerson, Thomas B. Holloway, John S. Atlas, Elliot L. Flocke, Frank M. Weber, Rodney J. Huey, L. Gregory Dibb, Jack E. Streets, David G. Brune, William H. TI Influence of lateral and top boundary conditions on regional air quality prediction: A multiscale study coupling regional and global chemical transport models SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GAS-AEROSOL EQUILIBRIUM; EASTERN UNITED-STATES; TROPOSPHERIC OZONE; TRACE-P; ART.; EMISSIONS; NOX; ASIA AB [1] The sensitivity of regional air quality model to various lateral and top boundary conditions is studied at 2 scales: a 60 km domain covering the whole USA and a 12 km domain over northeastern USA. Three global models (MOZART-NCAR, MOZART-GFDL and RAQMS) are used to drive the STEM-2K3 regional model with time-varied lateral and top boundary conditions (BCs). The regional simulations with different global BCs are examined using ICARTT aircraft measurements performed in the summer of 2004, and the simulations are shown to be sensitive to the boundary conditions from the global models, especially for relatively long-lived species, like CO and O-3. Differences in the mean CO concentrations from three different global-model boundary conditions are as large as 40 ppbv, and the effects of the BCs on CO are shown to be important throughout the troposphere, even near surface. Top boundary conditions show strong effect on O3 predictions above 4 km. Over certain model grids, the model's sensitivity to BCs is found to depend not only on the distance from the domain's top and lateral boundaries, downwind/upwind situation, but also on regional emissions and species properties. The near-surface prediction over polluted area is usually not as sensitive to the variation of BCs, but to the magnitude of their background concentrations. We also test the sensitivity of model to temporal and spatial variations of the BCs by comparing the simulations with time-varied BCs to the corresponding simulations with time-mean and profile BCs. Removing the time variation of BCs leads to a significant bias on the variation prediction and sometime causes the bias in predicted mean values. The effect of model resolution on the BC sensitivity is also studied. C1 Univ Iowa, Ctr Global & Reg Environm Res, Iowa City, IA 52242 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08540 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ N Carolina, Carolina Environm Program, Chapel Hill, NC 27599 USA. NOAA, Div Chem Sci, Earth Syst Res Lab, Boulder, CO 80305 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. RP Tang, YH (reprint author), NOAA, Natl Ctr Environm Protect, Environm Modeling Ctr, W-NP22 Room 207,5200 Auth Rd, Camp Springs, MD 20746 USA. EM youhua.tang@noaa.gov; gcarmich@engineering.uiowa.edu; nthongbo@cgrer.uiowa.edu; tchai@cgrer.uiowa.edu; larry.horowitz@noaa.gov; r.b.pierce@larc.nasa.gov; j.a.al-saadi@nasa.gov; pfister@ucar.edu; jeff_vukovich@unc.edu; m.a.avery@larc.nasa.gov; g.w.sachse@larc.nasa.gov; thomas.b.ryerson@noaa.gov; john.s.holloway@noaa.gov; eatlas@rsmas.miami.edu; ffl@ucar.edu; rweber@eas.gatech.edu; greg.huey@eas.gatech.edu; jack.dibb@unh.edu; dstreets@anl.gov; brune@ems.psu.edu RI Pfister, Gabriele/A-9349-2008; Chai, Tianfeng/E-5577-2010; Pierce, Robert Bradley/F-5609-2010; Holloway, John/F-9911-2012; Ryerson, Tom/C-9611-2009; Horowitz, Larry/D-8048-2014; Atlas, Elliot/J-8171-2015; Tang, Youhua/D-5205-2016; Manager, CSD Publications/B-2789-2015; OI Chai, Tianfeng/0000-0003-3520-2641; Pierce, Robert Bradley/0000-0002-2767-1643; Holloway, John/0000-0002-4585-9594; Horowitz, Larry/0000-0002-5886-3314; Tang, Youhua/0000-0001-7089-7915; Streets, David/0000-0002-0223-1350 NR 30 TC 47 Z9 48 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 25 PY 2007 VL 112 IS D10 AR D10S18 DI 10.1029/2006JD007515 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 163FC UT WOS:000246143200001 ER PT J AU Martin, P Stofan, ER Glaze, LS Smrekar, S AF Martin, P. Stofan, E. R. Glaze, L. S. Smrekar, S. TI Coronae of Parga Chasma, Venus SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID GLOBAL DISTRIBUTION; TECTONIC PATTERNS; VOLCANISM; EVOLUTION; STRESSES; FEATURES; ORIGIN; RISES; EARTH; ASSOCIATIONS AB [ 1] Parga Chasma is a 10,000 km long fracture and trough system in the southern hemisphere of Venus. In this study, we analyze coronae in the Parga region, addressing the relationship between corona and rift formation, the relationship of volcanism to rifting and coronae, and the overall evolution of the rift system. Our observations are compared with various models, with the aim of determining any causative relationships between corona formation, volcanism, and rifting. Our statistical analysis shows that coronae are randomly located within this region, indicating that corona locations are not significantly controlled by rifting, or by lithospheric loading caused by the earlier formation of other coronae. Our observations suggest that the two processes of corona and rift formation were occurring more or less synchronously, with no specific control on each other, but that coronae and rifting in this region are genetically related. We find a wide variation in the amount of volcanism associated with coronae across the Parga region, and no evidence for a deep-seated plume or multiple plumes beneath Parga Chasma. We suggest that the concentration of volcanic features in the Beta-Atla-Themis region may actually result from three independent but overlapping broad zones of deformation, corona formation, and enhanced volcanism associated with the three rifts ( Parga, Hecate, and Devana Chasmata), rather than one large zone of activity covering the whole of the region simultaneously. C1 Univ Durham, Sci Labs, Dept Earth Sci, Durham DH1 3LE, England. Proxemy Res, Laytonville, MD 20882 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Martin, P (reprint author), Univ Durham, Sci Labs, Dept Earth Sci, South Rd, Durham DH1 3LE, England. EM paula.martin@durham.ac.uk; ellen@proxemy.com; lori@proxemy.com; ssmrekar@jpl.nasa.gov RI Glaze, Lori/D-1314-2012 NR 55 TC 5 Z9 5 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 25 PY 2007 VL 112 IS E4 AR E04S03 DI 10.1029/2006JE002758 PG 23 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 163FQ UT WOS:000246144600002 ER PT J AU Ray, AK Tiwari, YN Roy, PK Chaudhuri, S Bose, SC Ghosh, RN Whittenberger, JD AF Ray, A. K. Tiwari, Y. N. Roy, P. K. Chaudhuri, S. Bose, S. C. Ghosh, R. N. Whittenberger, J. D. TI Creep rupture analysis and remaining life assessment of 2.25Cr-1Mo steel tubes from a thermal power plant SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE service exposed; 2.25Cr-1Mo steel; Larson-Miller parameter; LMP residual life ID STEAM PIPE; PREDICTION; BOILERS AB Superheater and reheater 2.25Cr-1Mo steel boiler tubes from a thermal power plant after 17 year of service at nominally 540 degrees C and 40 MPa were studied to predict their remnant life. The investigation included dimensional, hardness and tensile measurements in addition to accelerated stress rupture tests between 625 and 700 degrees C and microstructural examination. The microstructure of the service-exposed alloy was free from any signs of deterioration, and the hardness was within the expected ranges; however, tensile testing revealed an apparent loss of strength from room temperature to 600 degrees C. Accelerated rupture testing, on the other hand, did not reveal any degradation of rupture behaviour compared to that of the virgin alloy. Analysis of the stress rupture data predicted that the 17 years exposed superheater and reheater tubes could remain in continued service for at least 12 more years at the current stress-temperature conditions. (c) 2006 Elsevier B.V. All rights reserved. C1 Natl Met Lab, Jamshepur 831007, India. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Ray, AK (reprint author), Natl Met Lab, Jamshepur 831007, India. EM asokroy@nmlindia.org RI Sahu, Anjani/E-7590-2015 NR 19 TC 26 Z9 29 U1 1 U2 8 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD APR 25 PY 2007 VL 454 BP 679 EP 684 DI 10.1016/j.msea.2006.11.019 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 159WO UT WOS:000245898500096 ER PT J AU Kataoka, J Reeves, JN Iwasawa, K Markowitz, AG Mushotzky, RF Arimoto, M Takahashi, T Tsubuku, Y Ushio, M Watanabe, S Gallo, LC Madejski, GM Terashima, Y Isobe, N Tashiro, MS Kohmura, T AF Kataoka, Jun Reeves, James N. Iwasawa, Kazushi Markowitz, Alex G. Mushotzky, Richard F. Arimoto, Makoto Takahashi, Tadayuki Tsubuku, Yoshihiro Ushio, Masayoshi Watanabe, Shin Gallo, Luigi C. Madejski, Greg M. Terashima, Yuichi Isobe, Naoki Tashiro, Makoto S. Kohmura, Takayoshi TI Probing the disk-jet connection of the radio galaxy 3C 120 observed with Suzaku SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN LA English DT Article DE galaxies : active; galaxies : individual (3C 120); galaxies : Seyfert; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; RAY-TIMING-EXPLORER; HIGH-ENERGY EMISSION; BRIGHT QUASAR SURVEY; LINE REGION SIZES; X-RAY; XMM-NEWTON; BLACK-HOLE; SEYFERT-GALAXIES; BOARD SUZAKU AB We report on deep (40 ks x 4) observations of the bright broad line radio galaxy 3C 120 using Suzaku. The observations were spaced one week apart, and sampled a range of continuum fluxes. An excellent broadband spectrum was obtained over two decades of frequency (0.6 to 50 keV) within each 40 ks exposure. We clearly resolved the iron K emission-line complex, finding that it consists of a narrow K alpha core (sigma similar or equal to 110 eV or an EW of 60 eV), a 6.9 keV line, and an underlying broad iron line. Our confirmation of the broad line contrasts with the XMM-Newton observation in 2003, where the broad line was not required. The most natural interpretation of the broadline is iron Kline emission from a face-on accretion disk that is truncated at similar to 10 r(g). Above 10 keV, a relatively weak Compton hump was detected (reflection fraction of R similar or equal to 0.6), superposed on the primary X-ray continuum of Gamma similar or equal to 1.75. Thanks to the good photon statistics and low background of the Suzaku data, we clearly confirm the spectral evolution of 3C 120, whereby the variability amplitude decreases with increasing energy. More strikingly, we discovered that the variability is caused by a steep power-law component of Gamma similar or equal to 2.7, possibly related to non-thermal jet emission. We discuss our findings in the context of similarities and differences between radio-loud/quiet objects. C1 Tokyo Inst Technol, Dept Phys, Meguro, Tokyo 1528551, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Max Planck Inst Extraterr Phys, MPE, Garching, Germany. JAXA, Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. Ehime Univ, Dept Phys, Matsuyama, Ehime 7908577, Japan. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Inst Phys & Chem Res, Cosm Radiat Lab, Wako, Saitama 3510198, Japan. Saitama Univ, Dept Phys, Sakura, Saitama 3388570, Japan. Kogakuin Univ, Dept Phys, Hachioji, Tokyo 1920015, Japan. RP Kataoka, J (reprint author), Tokyo Inst Technol, Dept Phys, Meguro, Tokyo 1528551, Japan. EM kataoka@hp.phys.titech.ac.jp RI Tashiro, Makoto/J-4562-2012; XRAY, SUZAKU/A-1808-2009 NR 66 TC 50 Z9 50 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0004-6264 EI 2053-051X J9 PUBL ASTRON SOC JPN JI Publ. Astron. Soc. Jpn. PD APR 25 PY 2007 VL 59 IS 2 BP 279 EP 297 DI 10.1093/pasj/59.2.279 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 166TT UT WOS:000246404000003 ER PT J AU Inan, US Lehtinen, NG Moore, RC Hurley, K Boggs, S Smith, DM Fishman, GJ AF Inan, U. S. Lehtinen, N. G. Moore, R. C. Hurley, K. Boggs, S. Smith, D. M. Fishman, G. J. TI Massive disturbance of the daytime lower ionosphere by the giant gamma-ray flare from magnetar SGR 1806-20 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ELECTRON-PRECIPITATION; NUCLEAR EXPLOSIONS; VLF MEASUREMENTS; ENERGY; PERTURBATIONS; SGR-1806-20; WHISTLER; BURSTS AB [1] The giant gamma-ray flare from SGR 1806-20 created a massive disturbance in the daytime lower ionosphere, as evidenced by unusually large changes in amplitude/phase of subionospherically propagating VLF signals. The perturbations of the 21.4 kHz NPM (Lualualei, Hawaii) signal observed at PA (Palmer Station, Antarctica) correspond to electron densities increasing by a factor of similar to 100 to similar to 10(3) cm(-3) at similar to 60 km and similar or equal to 1000 to similar to 10 cm(-3) at similar to 30 km altitude. Enhanced conductivity produced by flare onset endured for >1 hour, the time scale determined by mutual neutralization. A brief (similar to 100 ms) low frequency (similar to 3 to 6 kHz) emission is also observed during the flare onset. C1 Stanford Univ, Star Lab, Space Telecommun & Radiosci Lab, Dept Elect Engn, Stanford, CA 94305 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94708 USA. Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Inan, US (reprint author), Stanford Univ, Star Lab, Space Telecommun & Radiosci Lab, Dept Elect Engn, 350 Serra Mall, Stanford, CA 94305 USA. EM nleht@stanford.edu NR 23 TC 38 Z9 38 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 21 PY 2007 VL 34 IS 8 AR L08103 DI 10.1029/GL0291745 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 160OD UT WOS:000245951300001 ER PT J AU Tian, BJ Yung, YL Waliser, DE Tyranowski, T Kuai, L Fetzer, EJ Irion, FW AF Tian, B. J. Yung, Y. L. Waliser, D. E. Tyranowski, T. Kuai, L. Fetzer, E. J. Irion, F. W. TI Intraseasonal variations of the tropical total ozone and their connection to the Madden-Julian Oscillation SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LOW-FREQUENCY OSCILLATIONS; LOWER STRATOSPHERE; UPPER TROPOSPHERE; TROPOPAUSE; VARIABILITY; OZONESONDES; PATTERNS; CYCLE; AIRS AB [1] We investigate the intraseasonal (30-90 day) variations in satellite-observed tropical total ozone (O-3) and their connection to the Madden-Julian Oscillation (MJO). Tropical total O-3 intraseasonal variations are large (similar to+/-10 DU) and comparable to those in annual and interannual time scales. These O-3 anomalies are mainly evident in the subtropics over the Pacific and eastern; hemisphere and propagate slowly eastward (similar to 5 m s(-1)). The subtropical negative (positive) O-3 anomalies are typically collocated with the subtropical upper troposphere anticyclones (cyclones) generated by equatorial MJO convection and flank or lie to the west of the equatorial enhanced (suppressed) MJO convection. The subtropical O-3 are anti-correlated with geopotential height anomalies near the tropopause and thus mainly associated with the O-3 variability in the stratosphere rather the troposphere. Over the equatorial regions, total O-3 anomalies are small. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Jagiellonian Univ, Inst Phys, PL-30059 Krakow, Poland. RP Tian, BJ (reprint author), CALTECH, Jet Prop Lab, Mail Stop 183-501,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM baijun.tian@jpl.nasa.gov RI Tian, Baijun/A-1141-2007 OI Tian, Baijun/0000-0001-9369-2373 NR 31 TC 38 Z9 41 U1 0 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 21 PY 2007 VL 34 IS 8 AR L08704 DI 10.1029/2007GL029451 PG 7 WC Geosciences, Multidisciplinary SC Geology GA 160OD UT WOS:000245951300002 ER PT J AU Luhmann, JG Kasprzak, WT Russell, CT AF Luhmann, J. G. Kasprzak, W. T. Russell, C. T. TI Space weather at Venus and its potential consequences for atmosphere evolution SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID SOLAR-WIND INTERACTION; O+ PICKUP IONS; PIONEER VENUS; MAGNETIC-FIELDS; ENERGETIC IONS; IONOSPHERE; PLASMA; MARS; NIGHTSIDE; IONOPAUSE AB [ 1] Space weather storms at the Earth are dominated by the magnetosphere's response to coronal mass ejections, or CMEs, whose disturbances propagate through the solar wind to 1 AU, and to a lesser extent by the pressure ridges associated with the interactions of solar wind streams with different properties. The interplanetary signatures of these events include high solar wind dynamic pressures and high interplanetary magnetic fields, the same parameters that cause compression and/or magnetization of the ionosphere at weakly magnetized Venus. The nature of Venus' response to these events is also expected to include increased atmosphere erosion by the solar wind interaction, a matter of potential interest for historical extrapolations of atmosphere escape. We consider the possible evidence for enhanced escape during these disturbances in the data from the Pioneer Venus Orbiter (PVO). Available magnetometer and plasma analyzer results are used to identify periods of interest and the interplanetary characteristics of the disturbed periods. It is found that the suprathermal (> 36 eV) ion measurements from the Pioneer Venus neutral mass spectrometer (ONMS) provide convincing evidence of the related enhanced escape of mostly O(+) suprathermal ions. The results provide the first direct demonstration that space weather has played an important role in Venus ( and other weakly magnetized planet) atmosphere loss through time. It is important to pursue study of these effects with the new measurements from Venus Express and, in light of the approaching solar activity cycle rising phase, extremely timely. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. RP Luhmann, JG (reprint author), Univ Calif Berkeley, Space Sci Lab, Centennial Dr & Grizzly Peak Blvd, Berkeley, CA 94720 USA. EM jgluhman@ssl.berkeley.edu NR 59 TC 28 Z9 28 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 21 PY 2007 VL 112 IS E4 AR E04S10 DI 10.1029/2006JE002820 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 160OY UT WOS:000245953400002 ER PT J AU Warwick, RS Jenkins, LP Read, AM Roberts, TP Owen, RA AF Warwick, R. S. Jenkins, L. P. Read, A. M. Roberts, T. P. Owen, R. A. TI An XMM-Newton view of M101 - III. Diffuse X-ray emission SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : individual : M101; galaxies : spiral; x-rays : galaxies; X-rays : ISM ID NEARBY SPIRAL GALAXIES; ROSAT PSPC OBSERVATIONS; CHANDRA OBSERVATIONS; INTERSTELLAR-MEDIUM; EVOLUTION-EXPLORER; SOURCE POPULATION; H-ALPHA; HOT GAS; SUPERWINDS; REMNANTS AB We present a study of the X-ray properties of the nearby face-on Scd spiral galaxy M101 based on recent XMM-Newton observations. In this third and final paper in the present series, we focus on the spatial and spectral properties of the residual emission, after excluding bright X-ray sources with L-X > 10(37) erg s(-1). Within a central region of radius 10 arcmin (21 kpc), the X-ray emission broadly traces the pattern of the spiral arms, establishing a strong link with recent star formation, but it also exhibits a radial scalelength of approximate to 2.6 arcmin (5.4 kpc) consistent with optical data. We estimate the soft X-ray luminosity within the central 5 arcmin (10.5 kpc) region to be L-X approximate to 2.1 x 10(39) erg s(-1) (0.5-2 keV), the bulk of which appears to originate as diffuse emission. We find a two-temperature thermal model best fits the spectral data with derived temperatures of 0.20(-0.01)(+0.01) and 0.68(-0.04)(+0.06)keV which are very typical of the diffuse components seen in other normal and starburst galaxies. More detailed investigation of the X-ray morphology reveals a strong correlation with images recorded in the far-ultraviolet through to V band, with the best match being with the U band. We interpret these results in terms of a clumpy thin-disc component which traces the spiral arms of M101 plus an extended lower halo component with large filling factor. C1 Univ Leicester, Dept Phys & Astron, Xray & Observat Astron Grp, Leicester LE1 7RH, Leics, England. NASA, Goddard Space Flight Ctr, Lab Xray Astrophys, Greenbelt, MD 20771 USA. Univ Durham, Dept Phys, Durham DH1 3LE, England. RP Warwick, RS (reprint author), Univ Leicester, Dept Phys & Astron, Xray & Observat Astron Grp, Univ Rd, Leicester LE1 7RH, Leics, England. EM rsw@star.le.ac.uk OI Jenkins, Leigh/0000-0001-9464-0719 NR 46 TC 11 Z9 11 U1 0 U2 0 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 21 PY 2007 VL 376 IS 4 BP 1611 EP 1620 DI 10.1111/j.1365-2966.2007.11571.x PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 156UP UT WOS:000245675700011 ER PT J AU Dresselhaus, MS Chen, G Tang, MY Yang, RG Lee, H Wang, DZ Ren, ZF Fleurial, JP Gogna, P AF Dresselhaus, Mildred S. Chen, Gang Tang, Ming Y. Yang, Ronggui Lee, Hohyun Wang, Dezhi Ren, Zhifeng Fleurial, Jean-Pierre Gogna, Pawan TI New directions for low-dimensional thermoelectric materials SO ADVANCED MATERIALS LA English DT Review ID QUANTUM-DOT SUPERLATTICES; THERMAL-CONDUCTIVITY; TRANSPORT-PROPERTIES; SI/GE SUPERLATTICES; NANOWIRE ARRAYS; HIGH FIGURE; BISMUTH; MERIT; GROWTH; DEVICES AB Many of the recent advances in enhancing the thermoelectric figure of merit are linked to nanoscale phenomena found both in bulk samples containing nanoscale constituents and in nanoscale samples themselves. Prior theoretical and experimental proof-of-principle studies on quantum-well superlattice and quantum-wire samples have now evolved into studies on bulk samples containing nanostructured constituents prepared by chemical or physical approaches. In this Review, nanostructural composites are shown to exhibit nanostructures and properties that show promise for thermoelectric applications, thus bringing together low-dimensional and bulk materials for thermoelectric applications. Particular emphasis is given in this Review to the ability to achieve 1) a simultaneous increase in the power factor and a decrease in the thermal conductivity in the same nanocomposite sample and for transport in the same direction and 2) lower values of the thermal conductivity in these nanocomposites as compared to alloy samples of the same chemical composition. The outlook for future research directions for nanocomposite thermoelectric materials is also discussed. C1 MIT, Cambridge, MA 02139 USA. Boston Coll, Chestnut Hill, MA 02467 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dresselhaus, MS (reprint author), MIT, 77 Massachusetts Ave, Cambridge, MA 02139 USA. EM millie@mgm.mit.edu RI Yang, Ronggui/H-1278-2011; Ren, Zhifeng/B-4275-2014; Chen, Gang/J-1325-2014 OI Chen, Gang/0000-0002-3968-8530 NR 64 TC 1684 Z9 1704 U1 136 U2 1145 PU WILEY-V C H VERLAG GMBH PI WEINHEIM PA PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY SN 0935-9648 J9 ADV MATER JI Adv. Mater. PD APR 20 PY 2007 VL 19 IS 8 BP 1043 EP 1053 DI 10.1002/adma.200600527 PG 11 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 167EB UT WOS:000246432800002 ER PT J AU Abbott, B Abbott, R Adhikari, R Agresti, J Ajith, P Allen, B Amin, R Anderson, SB Anderson, WG Araya, M Armandula, H Ashley, M Aston, S Aulbert, C Babak, S Ballmer, S Barish, BC Barker, C Barker, D Barr, B Barriga, P Barton, MA Bayer, K Belczynski, K Betzwieser, J Beyersdorf, P Bhawal, B Bilenko, IA Billingsley, G Black, E Blackburn, K Blackburn, L Blair, D Bland, B Bogue, L Bork, R Bose, S Brady, PR Braginsky, VB Brau, JE Brooks, A Brown, DA Bullington, A Bunkowski, A Buonanno, A Burman, R Busby, D Byer, RL Cadonati, L Cagnoli, G Camp, JB Cannizzo, J Cannon, K Cantley, CA Cao, J Cardenas, L Casey, MM Cepeda, C Charlton, P Chatterji, S Chelkowski, S Chen, Y Chin, D Chin, E Chow, J Christensen, N Cokelaer, T Colacino, CN Coldwell, R Cook, D Corbitt, T Coward, D Coyne, D Creighton, JDE Creighton, TD Crooks, DRM Cruise, AM Cumming, A Cutler, C Dalrymple, J D'Ambrosio, E Danzmann, K Davies, G De Vine, G DeBra, D Degallaix, J Dergachev, V Desai, S DeSalvo, R Dhurandar, S Di Credico, A Diaz, M Dickson, J Diederichs, G Dietz, A Doomes, EE Drever, RWP Dumas, JC Dupuis, RJ Ehrens, P Elliffe, E Etzel, T Evans, M Evans, T Fairhurst, S Fan, Y Fejer, MM Finn, LS Fotopoulos, N Franzen, A Franzen, KY Frey, RE Fricke, T Fritschel, P Frolov, VV Fyffe, M Garofoli, J Gholami, I Giaime, JA Giampanis, S Goda, K Goetz, E Goggin, L Gonzalez, G Gossler, S Grant, A Gras, S Gray, C Gray, M Greenhalgh, J Gretarsson, AM Grimmett, D Grosso, R Grote, H Grunewald, S Guenther, M Gustafson, R Hage, B Hanna, C Hanson, J Hardham, C Harms, J Harry, G Harstad, E Hayler, T Heefner, J Heng, IS Heptonstall, A Heurs, M Hewitson, M Hild, S Hindman, N Hirose, E Hoak, D Hoang, P Hosken, D Hough, J Howell, E Hoyland, D Hua, W Huttner, S Ingram, D Ito, M Itoh, Y Ivanov, A Jackrel, D Johnson, B Johnson, WW Jones, DI Jones, G Jones, R Ju, L Kalmus, P Kalogera, V Kasprzyk, D Katsavounidis, E Kawabe, K Kawamura, S Kawazoe, F Kells, W Khalili, FY Khan, A Kim, C King, P Klimenko, S Kokeyama, K Kondrashov, V Koranda, S Kozak, D Krishnan, B Kwee, P Lam, PK Landry, M Lantz, B Lazzarini, A Lee, B Lei, M Leonhardt, V Leonor, I Libbrecht, K Lindquist, P Lockerbie, NA Lormand, M Lubinski, M Luck, H Machenschalk, B MacInnis, M Mageswaran, M Mailand, K Malec, M Mandic, V Marka, S Markowitz, J Maros, E Martin, I Marx, JN Mason, K Matone, L Mavalvala, N McCarthy, R McClelland, DE McGuire, SC McHugh, M McKenzie, K McNabb, JWC Meier, T Melissinos, A Mendell, G Mercer, RA Meshkov, S Messaritaki, E Messenger, CJ Meyers, D Mikhailov, E Mitra, S Mitrofanov, VP Mitselmakher, G Mittleman, R Miyakawa, O Mohanty, S Moreno, G Mossavi, K MowLowry, C Moylan, A Mudge, D Mueller, G Muller-Ebhardt, H Mukherjee, S Munch, J Murray, P Myers, E Myers, J Newton, G Numata, K O'Reilly, B O'Shaughnessy, R Ottaway, DJ Overmier, H Owen, BJ Pan, Y Papa, MA Parameshwaraiah, V Pedraza, M Penn, S Pitkin, M Plissi, MV Prix, R Quetschke, V Raab, F Rabeling, D Radkins, H Rahkola, R Rakhmanov, M Rawlins, K Ray-Majumder, S Re, V Rehbein, H Reid, S Reitze, DH Ribichini, L Riesen, R Riles, K Rivera, B Robertson, DI Robertson, NA Robinson, C Roddy, S Rodriguez, A Rogan, AM Rollins, J Romano, JD Romie, J Route, R Rowan, S Rudiger, A Ruet, L Russell, P Ryan, K Sakata, S Samidi, M de la Jordana, LS Sandberg, V Sannibale, V Saraf, S Sarin, P Sathyaprakash, BS Sato, S Saulson, PR Savage, R Schediwy, S Schilling, R Schnabel, R Schofield, R Schutz, BF Schwinberg, P Scott, SM Seader, SE Searle, AC Sears, B Seifert, F Sellers, D Sengupta, AS Shawhan, P Sheard, B Shoemaker, DH Sibley, A Siemens, X Sigg, D Sintes, AM Slagmolen, B Slutsky, J Smith, J Smith, MR Sneddon, P Somiya, K Speake, C Spjeld, O Strain, KA Strom, DM Stuver, A Summerscales, T Sun, K Sung, M Sutton, PJ Tanner, DB Tarallo, M Taylor, R Taylor, R Thacker, J Thorne, KA Thorne, KS Thuring, A Tokmakov, KV Torres, C Torrie, C Traylor, G Trias, M Tyler, W Ugolini, D Ungarelli, C Vahlbruch, H Vallisneri, M Varvella, M Vass, S Vecchio, A Veitch, J Veitch, P Vigeland, S Villar, A Vorvick, C Vyachanin, SP Waldman, SJ Wallace, L Ward, H Ward, R Watts, K Webber, D Weidner, A Weinstein, A Weiss, R Wen, S Wette, K Whelan, JT Whitbeck, DM Whitcomb, SE Whiting, BF Wilkinson, C Willems, PA Willke, B Wilmut, I Winkler, W Wipf, CC Wise, S Wiseman, AG Woan, G Woods, D Wooley, R Worden, J Wu, W Yakushin, I Yamamoto, H Yan, Z Yoshida, S Yunes, N Zanolin, M Zhang, L Zhao, C Zotov, N Zucker, M zur Muhlen, H Zweizig, J AF Abbott, B. 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Danzmann, K. Davies, G. De Vine, G. DeBra, D. Degallaix, J. Dergachev, V. Desai, S. DeSalvo, R. Dhurandar, S. Di Credico, A. Diaz, M. Dickson, J. Diederichs, G. Dietz, A. Doomes, E. E. Drever, R. W. P. Dumas, J.-C. Dupuis, R. J. Ehrens, P. Elliffe, E. Etzel, T. Evans, M. Evans, T. Fairhurst, S. Fan, Y. Fejer, M. M. Finn, L. S. Fotopoulos, N. Franzen, A. Franzen, K. Y. Frey, R. E. Fricke, T. Fritschel, P. Frolov, V. V. Fyffe, M. Garofoli, J. Gholami, I. Giaime, J. A. Giampanis, S. Goda, K. Goetz, E. Goggin, L. Gonzalez, G. Gossler, S. Grant, A. Gras, S. Gray, C. Gray, M. Greenhalgh, J. Gretarsson, A. M. Grimmett, D. Grosso, R. Grote, H. Grunewald, S. Guenther, M. Gustafson, R. Hage, B. Hanna, C. Hanson, J. Hardham, C. Harms, J. Harry, G. Harstad, E. Hayler, T. Heefner, J. Heng, I. S. Heptonstall, A. Heurs, M. Hewitson, M. Hild, S. Hindman, N. Hirose, E. Hoak, D. Hoang, P. Hosken, D. Hough, J. Howell, E. Hoyland, D. Hua, W. Huttner, S. Ingram, D. Ito, M. Itoh, Y. Ivanov, A. Jackrel, D. Johnson, B. Johnson, W. W. Jones, D. I. Jones, G. Jones, R. Ju, L. Kalmus, P. Kalogera, V. Kasprzyk, D. Katsavounidis, E. Kawabe, K. Kawamura, S. Kawazoe, F. Kells, W. Khalili, F. Ya. Khan, A. Kim, C. King, P. Klimenko, S. Kokeyama, K. Kondrashov, V. Koranda, S. Kozak, D. Krishnan, B. Kwee, P. Lam, P. K. Landry, M. Lantz, B. Lazzarini, A. Lee, B. Lei, M. Leonhardt, V. Leonor, I. Libbrecht, K. Lindquist, P. Lockerbie, N. A. Lormand, M. Lubinski, M. Lueck, H. Machenschalk, B. MacInnis, M. Mageswaran, M. Mailand, K. Malec, M. Mandic, V. Marka, S. Markowitz, J. Maros, E. Martin, I. Marx, J. N. Mason, K. Matone, L. Mavalvala, N. McCarthy, R. McClelland, D. E. McGuire, S. C. McHugh, M. McKenzie, K. McNabb, J. W. C. Meier, T. Melissinos, A. Mendell, G. Mercer, R. A. Meshkov, S. Messaritaki, E. Messenger, C. J. Meyers, D. Mikhailov, E. Mitra, S. Mitrofanov, V. P. Mitselmakher, G. Mittleman, R. Miyakawa, O. Mohanty, S. Moreno, G. Mossavi, K. MowLowry, C. Moylan, A. Mudge, D. Mueller, G. Mueller-Ebhardt, H. Mukherjee, S. Munch, J. Murray, P. Myers, E. Myers, J. Newton, G. Numata, K. O'Reilly, B. O'Shaughnessy, R. Ottaway, D. J. Overmier, H. Owen, B. J. Pan, Y. Papa, M. A. Parameshwaraiah, V. Pedraza, M. Penn, S. Pitkin, M. Plissi, M. V. Prix, R. Quetschke, V. Raab, F. Rabeling, D. Radkins, H. Rahkola, R. Rakhmanov, M. Rawlins, K. Ray-Majumder, S. Re, V. Rehbein, H. Reid, S. Reitze, D. H. Ribichini, L. Riesen, R. Riles, K. Rivera, B. Robertson, D. I. Robertson, N. A. Robinson, C. Roddy, S. Rodriguez, A. Rogan, A. M. Rollins, J. Romano, J. D. Romie, J. Route, R. Rowan, S. Ruediger, A. Ruet, L. Russell, P. Ryan, K. Sakata, S. Samidi, M. de la Jordana, L. Sancho Sandberg, V. Sannibale, V. Saraf, S. Sarin, P. Sathyaprakash, B. S. Sato, S. Saulson, P. R. Savage, R. Schediwy, S. Schilling, R. Schnabel, R. Schofield, R. Schutz, B. F. Schwinberg, P. Scott, S. M. Seader, S. E. Searle, A. C. Sears, B. Seifert, F. Sellers, D. Sengupta, A. S. Shawhan, P. Sheard, B. Shoemaker, D. H. Sibley, A. Siemens, X. Sigg, D. Sintes, A. M. Slagmolen, B. Slutsky, J. Smith, J. Smith, M. R. Sneddon, P. Somiya, K. Speake, C. Spjeld, O. Strain, K. A. Strom, D. M. Stuver, A. Summerscales, T. Sun, K. Sung, M. Sutton, P. J. Tanner, D. B. Tarallo, M. Taylor, R. Taylor, R. Thacker, J. Thorne, K. A. Thorne, K. S. Thuering, A. Tokmakov, K. V. Torres, C. Torrie, C. Traylor, G. Trias, M. Tyler, W. Ugolini, D. Ungarelli, C. Vahlbruch, H. Vallisneri, M. Varvella, M. Vass, S. Vecchio, A. Veitch, J. Veitch, P. Vigeland, S. Villar, A. Vorvick, C. Vyachanin, S. P. Waldman, S. J. Wallace, L. Ward, H. Ward, R. Watts, K. Webber, D. Weidner, A. Weinstein, A. Weiss, R. Wen, S. Wette, K. Whelan, J. T. Whitbeck, D. M. Whitcomb, S. E. Whiting, B. F. Wilkinson, C. Willems, P. A. Willke, B. Wilmut, I. Winkler, W. Wipf, C. C. Wise, S. Wiseman, A. G. Woan, G. Woods, D. Wooley, R. Worden, J. Wu, W. Yakushin, I. Yamamoto, H. Yan, Z. Yoshida, S. Yunes, N. Zanolin, M. Zhang, L. Zhao, C. Zotov, N. Zucker, M. zur Muehlen, H. Zweizig, J. CA LIGO Sci Collaboration TI Searching for a stochastic background of gravitational waves with the laser interferometer gravitational-wave observatory SO ASTROPHYSICAL JOURNAL LA English DT Article DE gravitational waves ID PHASE-TRANSITIONS; STRING COSMOLOGY; LIMITS; ANISOTROPY; LIGO AB The Laser Interferometer Gravitational-Wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new Bayesian 90% upper limit is Omega(GW) x [H(0)/72 km s(-1) Mpc(-1))](2) < 6.5 x 10(-5). This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss the complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background. C1 CALTECH, Laser Interferometer Gravit Wave Observ, Pasadena, CA 91125 USA. Max Planck Inst Gravitat Phys, Albert Einstein Inst, Hannover, Germany. Univ Wisconsin, Milwaukee, WI 53201 USA. Louisiana State Univ, Baton Rouge, LA 70803 USA. Australian Natl Univ, Canberra, ACT, Australia. Univ Birmingham, Birmingham, W Midlands, England. Max Planck Inst Gravitat Phys, Albert Einstein Inst, Golm, Germany. MIT, Laser Interferometer Gravit Wave Observ, Cambridge, MA 02139 USA. Hanford Observ, Laser Interferometer Gravit Wave Observ, Richland, WA USA. Univ Glasgow, Glasgow, Lanark, Scotland. Univ Western Australia, Crawley, Australia. Northwestern Univ, Evanston, IL USA. Stanford Univ, Stanford, CA 94305 USA. Moscow MV Lomonosov State Univ, Moscow, Russia. Livingston Observ, Laser Interferometer Gravit Wave Observ, Livingston, LA USA. Washington State Univ, Pullman, WA 99164 USA. Univ Oregon, Eugene, OR 97403 USA. Univ Adelaide, Adelaide, SA, Australia. Univ Maryland, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Carleton Coll, Northfield, MN 55057 USA. Cardiff Univ, Cardiff, Wales. Univ Florida, Gainesville, FL USA. CALTECH, Pasadena, CA 91125 USA. Syracuse Univ, Syracuse, NY USA. Leibniz Univ Hannover, Hannover, Germany. Penn State Univ, University Pk, PA 16802 USA. Inter Univ Ctr Astron & Astrophys, Pune, Maharashtra, India. Univ Texas, Brownsville, TX USA. Texas Southmost Coll, Brownsville, TX USA. So Univ & A&M Coll, Baton Rouge, LA USA. Univ Rochester, Rochester, NY USA. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Embry Riddle Aeronaut Univ, Prescott, AZ USA. Columbia Univ, New York, NY USA. Natl Astron Observ Japan, Tokyo, Japan. Loyola Univ, New Orleans, LA 70118 USA. Hobart & William Smith Coll, Geneva, NY 14456 USA. Univ Illes Balears, Palma de Mallorca, Spain. Trinity Univ, San Antonio, TX USA. SE Louisiana Univ, Hammond, LA 70402 USA. Louisiana Tech Univ, Ruston, LA 71270 USA. RP Abbott, B (reprint author), CALTECH, Laser Interferometer Gravit Wave Observ, Pasadena, CA 91125 USA. RI Barriga, Pablo/A-3929-2008; Kawazoe, Fumiko/F-7700-2011; Kawabe, Keita/G-9840-2011; Lam, Ping Koy/A-5276-2008; McClelland, David/E-6765-2010; Martin, Iain/A-2445-2010; Hild, Stefan/A-3864-2010; Schutz, Bernard/B-1504-2010; Casey, Morag/C-9703-2010; Rowan, Sheila/E-3032-2010; Strain, Kenneth/D-5236-2011; Raab, Frederick/E-2222-2011; Lueck, Harald/F-7100-2011; Mow-Lowry, Conor/F-8843-2015; Ottaway, David/J-5908-2015; Howell, Eric/H-5072-2014; Messaritaki, Eirini/D-7393-2016; Tarallo, Marco/B-2096-2012; Sigg, Daniel/I-4308-2015; Harms, Jan/J-4359-2012; Chow, Jong/A-3183-2008; Frey, Raymond/E-2830-2016; Ward, Robert/I-8032-2014; Finn, Lee Samuel/A-3452-2009; Agresti, Juri/G-8168-2012; Mitrofanov, Valery/D-8501-2012; Bilenko, Igor/D-5172-2012; Allen, Bruce/K-2327-2012; Chen, Yanbei/A-2604-2013; Barker, David/A-5671-2013; Zhao, Chunnong/C-2403-2013; Ju, Li/C-2623-2013; Pitkin, Matthew/I-3802-2013; Vyatchanin, Sergey/J-2238-2012; Khalili, Farit/D-8113-2012; Vecchio, Alberto/F-8310-2015 OI Lam, Ping Koy/0000-0002-4421-601X; McClelland, David/0000-0001-6210-5842; Strain, Kenneth/0000-0002-2066-5355; Lueck, Harald/0000-0001-9350-4846; Zweizig, John/0000-0002-1521-3397; O'Shaughnessy, Richard/0000-0001-5832-8517; Whiting, Bernard F/0000-0002-8501-8669; Howell, Eric/0000-0001-7891-2817; Tarallo, Marco/0000-0001-5169-4987; Sigg, Daniel/0000-0003-4606-6526; Chow, Jong/0000-0002-2414-5402; Frey, Raymond/0000-0003-0341-2636; Ward, Robert/0000-0001-5503-5241; Whelan, John/0000-0001-5710-6576; Fairhurst, Stephen/0000-0001-8480-1961; Finn, Lee Samuel/0000-0002-3937-0688; Agresti, Juri/0000-0001-6119-2470; Allen, Bruce/0000-0003-4285-6256; Zhao, Chunnong/0000-0001-5825-2401; Pitkin, Matthew/0000-0003-4548-526X; Vecchio, Alberto/0000-0002-6254-1617 NR 42 TC 94 Z9 94 U1 1 U2 14 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2007 VL 659 IS 2 BP 918 EP 930 DI 10.1086/511329 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158ES UT WOS:000245774700005 ER PT J AU Sellgren, K Uchida, KI Werner, MW AF Sellgren, K. Uchida, K. I. Werner, M. W. TI The 15-20 mu m spitzer spectra of interstellar emission features in NGC 7023 SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; infrared : ISM; ISM : individual ( NGC 7023); ISM : lines and bands; ISM : molecules; reflection nebulae ID POLYCYCLIC AROMATIC-HYDROCARBONS; INFRARED-ABSORPTION-SPECTRA; ISO-SWS SPECTRA; RICH AGB STARS; MU-M; SPACE-TELESCOPE; OPTICAL-PROPERTIES; SILICATE MINERALOGY; PRESOLAR DIAMONDS; SPECTROGRAPH IRS AB We present 15-20 mu m long-slit spectra of NGC 7023 from the Infrared Spectrograph (IRS) on Spitzer. We observe recently discovered interstellar emission features at 15.9, 16.4, 17.0, 17.4, 17.8, and 18.9 mu m, throughout the reflection nebula. The 16.4 mu m emission feature peaks near the photodissociation front northwest of the star, as the aromatic emission features (AEFs) at 3.3, 6.2, and 11.3 mu m do. The 16.4 mu m emission feature is thus likely related to the AEFs and radiates by nonequilibrium emission. The new 18.9 mu m emission feature, by contrast, decreases monotonically with stellar distance. We consider candidate species for the 18.9 mu m feature, including polycyclic aromatic hydrocarbons, fullerenes, and diamonds. We describe future laboratory and observational research needed to identify the 18.9 mu m feature carrier. C1 Ohio State Univ, Dept Astron, Columbus, OH 43235 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sellgren, K (reprint author), Ohio State Univ, Dept Astron, Columbus, OH 43235 USA. EM sellgren@astronomy.ohio-state.edu NR 70 TC 56 Z9 57 U1 0 U2 7 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2007 VL 659 IS 2 BP 1338 EP 1351 DI 10.1086/511805 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158ES UT WOS:000245774700034 ER PT J AU Toma, K Ioka, K Sakamoto, T Nakamura, T AF Toma, Kenji Ioka, Kunihito Sakamoto, Takanori Nakamura, Takashi TI Low-luminosity GRB 060218: A collapsar jet from a neutron star, leaving a magnetar as a remnant? SO ASTROPHYSICAL JOURNAL LA English DT Review DE gamma rays : bursts; gamma rays : theory; supernovae : general ID GAMMA-RAY BURSTS; AFTERGLOW LIGHT CURVES; GRB 060218/SN 2006AJ; RELATIVISTIC JETS; SUPERNOVA RATES; VIEWING ANGLE; SWIFT DATA; ENERGY; MODEL; PROGENITORS AB The gamma-ray burst (GRB) 060218 has a luminosity similar to 10(5) times lower than that of typical long GRBs and is associated with a supernova (SN). The radio afterglow displays no jet break, so this burst might arise from a mildly relativistic spherical outflow produced by the SN shock sweeping the stellar surface. Since this model is energetically difficult, we propose that the radio afterglow is produced by a nonrelativistic phase of an initially collimated outflow ( jet). Our jet model is supported by the detection of optical linear polarization in the SN component. We also show analytically that the jet can penetrate a progenitor star. We analyzed the observational data of the prompt emission of this burst and obtained a smooth power-law light curve which might last longer than 10(6) s. This behavior contrasts with the long intermittent activities of the X-ray flares of typical GRBs, implying that the central engine of this burst is different from those of typical GRBs. This argument is consistent with the analysis of the SN component of this burst, which suggests that the progenitor star was less massive and collapsed to a neutron star instead of a black hole. The collimation-corrected event rate of such low-luminosity GRBs is estimated to be similar to 10 times higher than that of typical long GRBs, and they might form a different GRB population: low-luminosity GRBs are produced by mildly relativistic jets from neutron stars at the collapses of massive stars, while typical long GRBs are produced by highly relativistic jets from black holes. We suggest that the central engine of GRB 060218 is a pulsar (or a magnetar) with initial rotation period P-0 similar to 10 ms and magnetic field B similar to 10(16) G. A giant flare from the magnetar might be observed in future. C1 Kyoto Univ, Dept Phys, Kyoto 6068502, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CNR, Washington, DC 20418 USA. RP Toma, K (reprint author), Kyoto Univ, Dept Phys, Kyoto 6068502, Japan. EM toma@tap.scphys.kyoto-u.ac.jp; takanori@milkyway.gsfc.nasa.gov NR 104 TC 53 Z9 54 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2007 VL 659 IS 2 BP 1420 EP 1430 DI 10.1086/512481 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158ES UT WOS:000245774700041 ER PT J AU Brown, PJ Dessart, L Holland, ST Immler, S Landsman, W Blondin, S Blustin, AJ Breeveld, A Dewangan, GC Gehrels, N Hutchins, RB Kirshner, RP Mason, KO Mazzali, PA Milne, P Modjaz, M Roming, PWA AF Brown, Peter J. Dessart, Luc Holland, Stephen T. Immler, Stefan Landsman, Wayne Blondin, Stephane Blustin, Alexander J. Breeveld, Alice Dewangan, Gulab C. Gehrels, Neil Hutchins, Robert B. Kirshner, Robert P. Mason, Keith O. Mazzali, Paolo A. Milne, Peter Modjaz, Maryam Roming, Peter W. A. TI Early ultraviolet, optical, and X-ray observations of the type IIPSN 2005cs in M51 with Swift SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (M51); ultraviolet : general; X-rays : general ID PRELIMINARY SPECTRAL-ANALYSIS; II-P SUPERNOVAE; SN 2005CS; PLANETARY-NEBULAE; STANDARD CANDLES; STAR-FORMATION; DISTANCE; GALAXY; EMISSION; TELESCOPE AB We report early photospheric-phase observations of the Type IIP supernova ( SN) 2005cs obtained by the Swift ultraviolet-optical and X-ray telescopes. Observations started within 2 days of discovery and continued on a regular basis for 3 weeks. During this time the V-band magnitude remained essentially constant, while the UV was initially bright, but steadily faded until below the brightness of an underlying UV-bright H II region. This UV decay is similar to SNe II observed by the International Ultraviolet Explorer. UV grism spectra show the P Cygni absorption of Mg II 2798 8, indicating a photospheric origin of the UV flux. Based on non-LTE model atmosphere calculations with the CMFGEN code, we associate the rapid evolution of the UV flux with the cooling of the ejecta, the peak of the spectral energy distribution ( SED) shifting from similar to 700 angstrom on June 30 to similar to 1200 angstrom on July 5. Furthermore, the corresponding recombination of the ejecta, e. g., the transition from Fe III to Fe II, induces a considerable strengthening of metal line-blanketing at and above the photosphere, blocking more and more effectively this fading UV flux. SN 2005cs was not detected in the X-ray band, and the upper limit to the X-ray luminosity yields a limit to the mass-loss rate of the progenitor of M less than or similar to 1 x 10(-5) yr(-1) (v(w)/10 km s(-1)). Overall, Swift represents a unique opportunity to capture the early and fast evolution of Type II SNe in the UV, providing additional constraints on the reddening, the SED shortward of 4000 angstrom, and the ionization state and temperature of the photon-decoupling regions. C1 Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Univ Arizona, Dept Astron, Tucson, AZ 85721 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. NASA, Goddard Space Flight Ctr, Astrophys Sci Div, Xray Astrophys Branch, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. UCL, Mullard Space Sci Lab, Dept Space & Climate Phys, Dorking RH5 6NT, Surrey, England. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. NASA, Goddard Space Flight Ctr, Astrophys Sci Div, Astroparticle Phys Lab, Greenbelt, MD 20771 USA. Osserv Astron Trieste, INAF, I-34131 Trieste, Italy. Max Planck Inst Astrophys, D-85741 Garching, Germany. RP Brown, PJ (reprint author), Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. EM pbrown@astro.psu.edu RI Gehrels, Neil/D-2971-2012 NR 57 TC 33 Z9 33 U1 1 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2007 VL 659 IS 2 BP 1488 EP 1495 DI 10.1086/511968 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158ES UT WOS:000245774700046 ER PT J AU Luhman, KL Allers, KN Jaffe, DT Cushing, MC Williams, KA Slesnick, CL Vacca, WD AF Luhman, K. L. Allers, K. N. Jaffe, D. T. Cushing, M. C. Williams, K. A. Slesnick, C. L. Vacca, W. D. TI Ophiuchus 1622-2405: Not a planetary-mass binary SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : visual; infrared : stars; stars : evolution; stars : formation; stars : low-mass, brown dwarfs; stars : pre-main-sequence ID YOUNG BROWN DWARFS; NEAR-INFRARED SPECTRA; STAR-FORMING REGION; SCORPIUS OB ASSOCIATION; EVOLUTIONARY MODELS; SOLAR NEIGHBORHOOD; IC 348; SPECTROSCOPY; CLUSTER; CANDIDATES AB We present an analysis of the mass and age of the young low-mass binary Oph 1622-2405. Using resolved optical spectroscopy of the binary, we measure spectral types of M7.25 +/- 0.25 and M8.75 +/- 0.25 for the A and B components, respectively. We show that our spectra are inconsistent with the spectral types of M9 and M9.5-L0 from Jayawardhana & Ivanov and M9 +/- 0.5 and M9.5 +/- 0.5 from Close and coworkers. Based on our spectral types and the theoretical evolutionary models of Chabrier and Baraffe, we estimate masses of similar to 0.055 and similar to 0.019 M-circle dot for Oph 1622-2405A and B, which are significantly higher than the values of 0.013 and 0.007 M-circle dot derived by Jayawardhana & Ivanov and above the range of masses observed for extrasolar planets (M less than or similar to 0.015 M-circle dot). Planet-like mass estimates are further contradicted by our demonstration that Oph 1622-2405A is only slightly later (by 0.5 subclass) than the composite of the young eclipsing binary brown dwarf 2M 0535-0546, whose components have dynamical masses of 0.034 and 0.054 M-circle dot. To constrain the age of Oph 1622-2405, we compare the strengths of gravity-sensitive absorption lines in optical and near-infrared spectra of the primary to lines in field dwarfs (tau > 1 Gyr) and members of Taurus (tau similar to 1 Myr) and Upper Scorpius (tau similar to 5 Myr). The line strengths for Oph 1622-2405A are inconsistent with membership in Ophiuchus (tau < 1 Myr) and instead indicate an age similar to that of Upper Sco, which is in agreement with a similar analysis performed by Close and coworkers. We conclude that Oph 1622-2405 is part of an older population in Sco-Cen, perhaps Upper Sco itself. C1 Univ Texas, Dept Astron, Austin, TX 78712 USA. Univ Hawaii Manoa, Astron Inst, Honolulu, HI 96822 USA. Univ Hawaii Manoa, Infrared Telescope Facil, Honolulu, HI 96822 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. CALTECH, MS105 24, Dept Astron, Pasadena, CA 91125 USA. NASA, Ames Res Ctr, USRA, SOFIA,MS N211 3, Moffett Field, CA 94035 USA. RP Luhman, KL (reprint author), Univ Texas, Dept Astron, Austin, TX 78712 USA. EM kluhman@astro.psu.edu OI Williams, Kurtis/0000-0002-1413-7679 NR 49 TC 32 Z9 32 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2007 VL 659 IS 2 BP 1629 EP 1636 DI 10.1086/512539 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158ES UT WOS:000245774700059 ER PT J AU Fortney, JJ Marley, MS Barnes, JW AF Fortney, J. J. Marley, M. S. Barnes, J. W. TI Planetary radii across five orders of magnitude in mass and stellar insolation: Application to transits SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : eclipsing; planetary systems ID EXTRASOLAR GIANT PLANETS; BROWN DWARFS; THERMAL STRUCTURE; TERRESTRIAL PLANETS; PHASE-SEPARATION; SOLAR-SYSTEM; HD 209458B; EVOLUTION; ATMOSPHERE; NEPTUNE AB To aid in the physical interpretation of planetary radii constrained through observations of transiting planets, or eventually direct detections, we compute model radii of pure hydrogen-helium, water, rock, and iron planets, along with various mixtures. Masses ranging from 0.01 Earth masses to 10 Jupiter masses at orbital distances of 0.02-10 AU are considered. For hydrogen-helium rich planets, our models are the first to couple planetary evolution to stellar irradiation over a wide range of orbital separations (0.02-10 AU) through a nongray radiative-convective equilibrium atmosphere model. Stellar irradiation retards the contraction of giant planets, but its effect is not a simple function of the irradiation level: a planet at 1AU contracts as slowly as a planet at 0.1 AU. We confirm the assertion of Guillot that very old giant planets under modest stellar irradiation (like that received by Jupiter and Saturn) develop isothermal atmospheric radiative zones once the planet's intrinsic flux drops to a small fraction of the incident flux. For hydrogen-helium planets, we consider cores up to 90% of the total planet mass, comparable to those of Uranus and Neptune. If "hot Neptunes'' have maintained their original masses and are not remnants of more massive planets, radii of similar to 0.30-0.45 RJ are expected. Water planets are similar to 40%-50% larger than rocky planets, independent of mass. Finally, we provide tables of planetary radii at various ages and compositions, and for ice-rock-iron planets we fit our results to analytic functions, which will allow for quick composition estimates, given masses and radii, or mass estimates, given only planetary radii. These results will assist in the interpretation of observations for both the current transiting planet surveys as well as upcoming space missions, including COROT and Kepler. C1 NASA, Ames Res Ctr, Space Sci & Astrobiol Div, Moffett Field, CA 94035 USA. SETI Inst, Carl Sagan Ctr, Mountain View, CA 94043 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. RP Fortney, JJ (reprint author), NASA, Ames Res Ctr, Space Sci & Astrobiol Div, Moffett Field, CA 94035 USA. EM jfortney@arc.nasa.gov; mark.s.marley@nasa.gov; jbarnes@c3po.lpl.arizona.edu RI Barnes, Jason/B-1284-2009; OI Barnes, Jason/0000-0002-7755-3530; Fortney, Jonathan/0000-0002-9843-4354 NR 79 TC 455 Z9 458 U1 1 U2 13 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2007 VL 659 IS 2 BP 1661 EP 1672 DI 10.1086/512120 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158ES UT WOS:000245774700061 ER PT J AU Corti, G Poletto, G Suess, ST Moore, RL Sterling, AC AF Corti, Gianni Poletto, Giannina Suess, Steve T. Moore, Ronald L. Sterling, Alphonse C. TI Cool-plasma jets that escape into the outer corona SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona ID X-RAY TELESCOPE; WHOLE SUN MONTH; ENERGETIC PARTICLE EVENTS; ULTRAVIOLET SPECTROSCOPY; DIAGNOSTIC SPECTROMETER; MASS EJECTIONS; SOLAR MINIMUM; WHITE-LIGHT; MISSION; REGION AB We report on observations acquired in 2003 May during a SOHO-Ulysses quadrature campaign. The UVCS slit was set normal to the radial of the Sun along the direction to Ulysses at 1.7 R-circle dot, at a northern latitude of 14.5 degrees. From May 25 to May 28, UVCS acquired spectra of several short-lived ejections that represent the extension at higher altitudes of recursive EIT jets, imaged in He ii lambda 304. The jets were visible also in LASCO images and seem to propagate along the radial to Ulysses. UVCS spectra showed an unusually high emission in cool lines, lasting for about 10-25 minutes, with no evidence of hot plasma. Analysis of the cool line emission allowed us to infer the physical parameters (temperature, density, and outward velocity) of jet plasma and the evolution of these quantities as the jet crossed the UVCS slit. From these quantities, we estimated the energy needed to produce the jet. We also looked for any evidence of the events in the in situ data. We conclude by comparing our results with those of previous works on similar events and propose a scenario that accounts for the observed magnetic setting of the source of the jets and allows the jets to be magnetically driven. C1 INAF, Observ Astrofis Arcetri, I-50125 Florence, Italy. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Corti, G (reprint author), INAF, Observ Astrofis Arcetri, I-50125 Florence, Italy. EM corti@arcetri.astro.it; poletto@arcetri.astro.it NR 30 TC 9 Z9 9 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2007 VL 659 IS 2 BP 1702 EP 1712 DI 10.1086/512233 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158ES UT WOS:000245774700065 ER PT J AU Butner, HM Charnley, SB Ceccarelli, C Rodgers, SD Pardo, JR Parise, B Cernicharo, J Davis, GR AF Butner, H. M. Charnley, S. B. Ceccarelli, C. Rodgers, S. D. Pardo, J. R. Parise, B. Cernicharo, J. Davis, G. R. TI Discovery of interstellar heavy water SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; ISM : individual (IRAS 16293-2422); ISM : molecules; stars : formation ID PROTOSTAR IRAS 16293-2422; HOT MOLECULAR CORES; MASS STAR-FORMATION; DEUTERIUM FRACTIONATION; DEUTERATED MOLECULES; SURFACE-CHEMISTRY; 1ST DETECTION; METHANOL; IRAS-16293-2422; MILLIMETER AB We report the discovery of doubly deuterated water (D2O, heavy water) in the interstellar medium. Using the James Clerk Maxwell Telescope and the Caltech Submillimeter Observatory 10 m telescope, we detected the 1(10)- 1(01) transition of para-D2O at 316.7998 GHz in both absorption and emission toward the protostellar binary system IRAS 16293-2422. Assuming that the D2O exists primarily in the warm regions where water ices have been evaporated (i.e., in a "hot corino" environment), we determine a total column density of N(D2O) of 1.0 x 10(13) cm(-2) and a fractional abundance of D2O/H-2 = 1.7 x 10(-10). The derived column density ratios for IRAS 16293-2422 are D2O/HDO = 1.7 x 10(-3) and D2O/H2O = 5 x 10(-5) for the hot corino gas. Steady state models of water ice formation, either in the gas phase or on grains, predict D2O/HDO ratios that are about 4 times larger than that derived from our observations. For water formation on grain surfaces to be a viable explanation, a larger H2O abundance than that measured in IRAS 16293-2422 is required. Alternatively, the observed D2O/HDO ratio could be indicative of gas-phase water chemistry prior to a chemical steady state being attained, such as would have occurred during the formation of this source. Future observations with the Herschel Space Observatory satellite will be important for settling this issue. C1 Joint Astron Ctr, Hilo, HI 96720 USA. NASA, Ames Res Ctr, Space Sci & Astrobiol Div, Moffett Field, CA 94035 USA. Observ Grenoble, Astrophys Lab, F-38041 Grenoble, France. CSIC, Dept Astrofis Mol & Infarroja, Inst Estructura Mat, E-28006 Madrid, Spain. Max Planck Inst Radioastron, D-53121 Bonn, Germany. RP Butner, HM (reprint author), James Madison Univ, Dept Phys, Harrisonburg, VA 22807 USA. EM h.butner@jach.hawaii.edu RI Charnley, Steven/C-9538-2012; OI Butner, Harold/0000-0003-4899-2064 NR 52 TC 43 Z9 43 U1 3 U2 9 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2007 VL 659 IS 2 BP L137 EP L140 DI 10.1086/517883 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158EV UT WOS:000245775000014 ER PT J AU Cooray, A Sullivan, I Chary, RR Bock, JJ Dickinson, M Ferguson, HC Keating, B Lange, A Wright, EL AF Cooray, Asantha Sullivan, Ian Chary, Ranga-Ram Bock, James J. Dickinson, Mark Ferguson, Henry C. Keating, Brian Lange, Andrew Wright, Edward L. TI IR background anisotropies in Spitzer goods images and constraints on first galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE diffuse radiation; infrared : galaxies; large-scale structure of universe ID STARS; LIGHT; TELESCOPE AB We describe the angular power spectrum of unresolved 3.6 mu m IR light in Spitzer GOODS fields. The amplitude of the anisotropy spectrum decreases with the decreasing flux threshold to which resolved sources are removed from images. When all pixels above a flux threshold of 24.6 Vega magnitudes are removed, the power spectrum of the remaining pixels has a shape on arcminute angular scales that is consistent with unresolved, faint galaxies at 1 < z < 4 with flux below 23 Vegamag and a total 3.6 mu m intensity between 0.1 and 0.8 nW m (-2) sr(-1). The amplitude of unresolved IR background clustering is further reduced when regions containing optical ACS sources with no IR counterparts are also masked out. We take this as evidence that the most likely identification of the sources responsible for the excess power are low-redshift galaxies. Our anisotropy measurements, however, allow for the possibility that unresolved sources at z > 8 contribute to the IR background with a 3.6 mu m intensity below about 0.6 nW m(-2) sr(-1). Based on resolved counts and unresolved fluctuations, we find that, at most, about 7.0 nW m(-2) sr(-1) can be ascribed to galaxies. C1 Univ Calif Irvine, Dept Phys & Astron, Ctr Cosmol, Irvine, CA 92697 USA. CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Opt Astron Observ, Tucson, AZ 85719 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA. RP Cooray, A (reprint author), Univ Calif Irvine, Dept Phys & Astron, Ctr Cosmol, Irvine, CA 92697 USA. EM acooray@uci.edu NR 22 TC 29 Z9 29 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2007 VL 659 IS 2 BP L91 EP L94 DI 10.1086/517969 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158EV UT WOS:000245775000003 ER PT J AU Pittman, JV Weinstock, EM Oglesby, RJ Sayres, DS Smith, JB Anderson, JG Cooper, OR Wofsy, SC Xueref, I Gerbig, C Daube, BC Richard, EC Ridley, BA Weinheimer, AJ Loewenstein, M Jost, HJ Lopez, JP Mahoney, MJ Thompson, TL Hargrove, WW Hoffman, FM AF Pittman, Jasna V. Weinstock, Elliot M. Oglesby, Robert J. Sayres, David S. Smith, Jessica B. Anderson, James G. Cooper, Owen R. Wofsy, Steven C. Xueref, Irene Gerbig, Cristoph Daube, Bruce C. Richard, Erik C. Ridley, Brian A. Weinheimer, Andrew J. Loewenstein, Max Jost, Hans-Jurg Lopez, Jimena P. Mahoney, Michael J. Thompson, Thomas L. Hargrove, William W. Hoffman, Forrest M. TI Transport in the subtropical lowermost stratosphere during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID IN-SITU OBSERVATIONS; UPPER TROPOSPHERE; REACTIVE NITROGEN; WATER-VAPOR; SEASONAL CYCLE; UV-ABSORPTION; NEW-MEXICO; TROPOPAUSE; OZONE; EXCHANGE AB [ 1] We use in situ measurements of water vapor (H2O), ozone (O-3), carbon dioxide (CO2), carbon monoxide (CO), nitric oxide (NO), and total reactive nitrogen (NOy) obtained during the CRYSTAL-FACE campaign in July 2002 to study summertime transport in the subtropical lowermost stratosphere. We use an objective methodology to distinguish the latitudinal origin of the sampled air masses despite the influence of convection, and we calculate backward trajectories to elucidate their recent geographical history. The methodology consists of exploring the statistical behavior of the data by performing multivariate clustering and agglomerative hierarchical clustering calculations and projecting cluster groups onto principal component space to identify air masses of like composition and hence presumed origin. The statistically derived cluster groups are then examined in physical space using tracer-tracer correlation plots. Interpretation of the principal component analysis suggests that the variability in the data is accounted for primarily by the mean age of air in the stratosphere, followed by the age of the convective influence, and last by the extent of convective influence, potentially related to the latitude of convective injection (Dessler and Sherwood, 2004). We find that high-latitude stratospheric air is the dominant source region during the beginning of the campaign while tropical air is the dominant source region during the rest of the campaign. Influence of convection from both local and nonlocal events is frequently observed. The identification of air mass origin is confirmed with backward trajectories, and the behavior of the trajectories is associated with the North American monsoon circulation. C1 Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Bay Area Environm Res Inst, Sonoma, CA 95476 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Nebraska, Dept Geosci, Lincoln, NE 68588 USA. NOAA, Earth Syst Res Lab, Boulder, CO 80305 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80305 USA. RP Pittman, JV (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. EM jasna.pittman@nasa.gov RI Manager, CSD Publications/B-2789-2015; Cooper, Owen/H-4875-2013; Gerbig, Christoph/L-3532-2013; Hoffman, Forrest/B-8667-2012 OI Gerbig, Christoph/0000-0002-1112-8603; Hoffman, Forrest/0000-0001-5802-4134 NR 53 TC 5 Z9 5 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 20 PY 2007 VL 112 IS D8 AR D08304 DI 10.1029/2006JD007851 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 160OI UT WOS:000245951800010 ER PT J AU Spak, S Holloway, T Lynn, B Goldberg, R AF Spak, Scott Holloway, Tracey Lynn, Barry Goldberg, Richard TI A comparison of statistical and dynamical downscaling for surface temperature in North America SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; CLIMATE-CHANGE SCENARIOS; REGIONAL CLIMATE; AIR-TEMPERATURE; LOCAL CLIMATE; CENTRAL-EUROPE; VARIABILITY; SENSITIVITY; INTERPOLATION; PREDICTORS AB [ 1] Projections from general circulation model (GCM) simulations must be downscaled to the high spatial resolution needed for assessing local and regional impacts of climate change, but uncertainties in the downscaling process are difficult to quantify. We employed a multiple linear regression model and the MM5 dynamical model to downscale June, July, and August monthly mean surface temperature over eastern North America under greenhouse gas-driven climate change simulation by the NASA GISS GCM. Here we examine potential sources of apparent agreement between the two classes of models and show that arbitrary parameters in a statistical model contribute significantly to the level of agreement with dynamical downscaling. We found that the two methods and all permutations of regression parameters generally exhibited comparable skill at simulating observations, although spatial patterns in temperature across the region differed. While the two methods projected similar regional mean warming over the period 2000 - 2087, they developed different spatial patterns of temperature across the region, which diverged further from historical differences. We found that predictor domain size was a negligible factor for current conditions, but had a much greater influence on future surface temperature change than any other factor, including the data sources. The relative importance of SD model inputs to downscaled skill and domain-wide agreement with MM5 for summertime surface temperature over North America in descending order is Predictor Domain; Training Data/Predictor Model; Predictor Variables; and Predictor Grid Resolution. Our results illustrate how statistical downscaling may be used as a proxy for dynamical models in sensitivity analysis. C1 Univ Wisconsin, Ctr Sustainabil & Global Environm, Madison, WI 53726 USA. Columbia Univ, Ctr Climate Syst Res, New York, NY 10025 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Spak, S (reprint author), Univ Wisconsin, Ctr Sustainabil & Global Environm, 1710 Univ Ave,Room 207, Madison, WI 53726 USA. RI Spak, Scott/B-7331-2008 OI Spak, Scott/0000-0002-8545-1411 NR 46 TC 36 Z9 37 U1 1 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 20 PY 2007 VL 112 IS D8 AR D08101 DI 10.1029/2005JD006712 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 160OI UT WOS:000245951800001 ER PT J AU Khazanov, GV Gamayunov, KV Gallagher, DL Kozyra, JU Liemohn, MW AF Khazanov, G. V. Gamayunov, K. V. Gallagher, D. L. Kozyra, J. U. Liemohn, M. W. TI Self-consistent model of magnetospheric ring current and propagating electromagnetic ion cyclotron waves: 2. Wave-induced ring current precipitation and thermal electron heating SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID AURORAL RED ARCS; STORM; PLASMASPHERE; PLASMAPAUSE; FLUXES AB [1] This paper continues presentation and discussion of the results from our new global self-consistent theoretical model of interacting ring current ions and propagating electromagnetic ion cyclotron waves (Khazanov et al., 2006) currently developing in NASA Marshall Space Flight Center. To study the effects of electromagnetic ion cyclotron wave propagation and refraction on the wave induced ring current precipitation and heating of the thermal plasmaspheric electrons, we simulate the May 1998 storm. The main findings after the simulation can be summarized as follows. First, the wave induced ring current precipitation exhibits quite a lot of fine structure and is highly organized by location of the plasmapause gradient. The strongest fluxes of about 4 x 10(6) (cm(2) s sr)(-1) are observed during the main and early recovery phases of the storm. The very interesting and probably more important finding is that in a number of cases the most intense precipitating fluxes are not connected to the most intense waves in simple manner. The characteristics of the wave power spectral density distribution over the wave normal angle are extremely crucial for the effectiveness of the ring current ion scattering. Second, comparison of the global proton precipitating patterns with the results from RAM (Kozyra et al., 1997a) reveals that although we observe a qualitative agreement between the localizations of the wave induced precipitations in the models, there is no quantitative agreement between the magnitudes of the fluxes. The quantitative differences are mainly due to a qualitative difference between the characteristics of the wave power spectral density distributions over the wave normal angle in RAM and in our model. Third, the heat fluxes to plasmaspheric electrons caused by Landau resonate energy absorption from electromagnetic ion cyclotron waves are observed in the postnoon-premidnight MLT sector and can reach the magnitude of 10(11) eV/(cm(2) s). The Coulomb energy degradation of the RC H+ and O+ ions maximizes at about 10(11) eV/(cm(2) s) and typically leads to electron energy deposition rates of about 2 x 10(10) eV/(cm(2) s) which are observed during two periods, 32 - 48 hours and 76 - 86 hours after 1 May, 0000 UT. The theoretically derived spatial structure of the thermal electron heating caused by interaction of the ring current with the plasmasphere is strongly supported by concurrent and conjugate plasma measurements from the plasmasphere, ring current, and topside ionosphere (Gurgiolo et al., 2005). Finally, the wave induced intense electron heating has a structure of the spot-like patches along the most enhanced density gradients in the plasmasphere boundary layer and can be a possible driver of the observed but still not explained small-scale structures of enhanced emissions in the stable auroral red arcs. C1 NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Dept Space Sci, Huntsville, AL 35805 USA. Univ Michigan, Space Phys Res Lab, Ann Arbor, MI 49109 USA. RP Khazanov, GV (reprint author), NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Dept Space Sci, 320 Sparkman Dr, Huntsville, AL 35805 USA. EM george.khazanov@msfc.nasa.gov; konstantin.gamayunov@msfc.gov; dennis.l.gallagher@nasa.gov; jukozyra@umich.edu; liemohn@umich.edu RI Gamayunov, Konstantin/A-8505-2009; Liemohn, Michael/H-8703-2012 OI Gamayunov, Konstantin/0000-0002-8768-8527; Liemohn, Michael/0000-0002-7039-2631 NR 16 TC 18 Z9 18 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 20 PY 2007 VL 112 IS A4 AR A04209 DI 10.1029/2006JA012033 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 160PC UT WOS:000245953800004 ER PT J AU Pilcher, CB AF Pilcher, Carl B. TI Astrobiology and missions at NASA SO SCIENCE LA English DT Letter C1 NASA, Ames Res Ctr, Astrobiol Inst, Moffett Field, CA 94035 USA. RP Pilcher, CB (reprint author), NASA, Ames Res Ctr, Astrobiol Inst, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD APR 20 PY 2007 VL 316 IS 5823 BP 368 EP 368 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 158RY UT WOS:000245813400017 PM 17446372 ER PT J AU Vallina, SM Simo, R Gasso, S De Boyer-Montegut, C del Rio, E Jurado, E Dachs, J AF Vallina, S. M. Simo, R. Gasso, S. De Boyer-Montegut, C. del Rio, E. Jurado, E. Dachs, J. TI Analysis of a potential "solar radiation dose-dimethylsulfide-cloud condensation nuclei'' link from globally mapped seasonal correlations SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID SEA-SALT SULFATE; MARINE BOUNDARY-LAYER; EASTERN MEDITERRANEAN ATMOSPHERE; HIGH-RESOLUTION RADIOMETER; EQUATORIAL PACIFIC-OCEAN; TROPICAL INDIAN-OCEAN; NORTH-ATLANTIC OCEAN; EXPERIMENT ACE 1; SULFUR CYCLE; FIELD OBSERVATIONS AB [ 1] The CLAW postulate states that an increase in solar irradiance or in the heat flux to the ocean can trigger a biogeochemical response to counteract the associated increase in temperature and available sunlight. This natural ( negative) feedback mechanism would be based on a multistep response: first, an increase in seawater dimethylsulfide concentrations (DMSw) and therefore its fluxes to the atmosphere (DMSflux); second, an increase in the atmospheric cloud condensation nuclei (CCN) burden as a consequence of DMS oxidation to form biogenic CCN (CCNbio); and third, an increase in cloud albedo due to higher CCN numbers. Monthly global climatological fields of the solar radiation dose in the upper mixed layer (SRD), surface oceanic DMSw, model outputs of hydroxyl radical concentrations ( OH), and satellite-derived CCN numbers (CCNs) are analyzed in order to evaluate the proposed "solar radiation dose-DMS-CCN'' link from a global point of view. OH is included as the main atmospheric oxidant of the estimated DMSflux to produce CCNbio. Global maps of seasonal correlations between the variables show that the solar radiation dose is highly ( positively) correlated with seawater dimethylsulfide over most of the global ocean and that atmospheric DMS oxidation is highly ( positively) correlated with CCNs over large regions. These couplings are stronger at high latitudes, whereas the regions with negative or no correlation are located at low latitudes around the equator. However, CCNbio estimates for 15 regions of the global ocean show that DMS oxidation can be an important contributor to the CCNs burden only over pollution-free regions, while it would have a minor contribution over regions with high loads of continental aerosols. Globally, the mean annual contribution of CCNbio to total CCNs is estimated to be approximate to 30%. Our results support that an oceanic biogenic mechanism that modulates cloud formation and albedo can indeed occur, although its impact seems rather weak over regions under a strong influence of continental aerosols. Nevertheless, our approach does not fully rule out that the observed correlations are due to an independent seasonal variation of the studied variables; seasonal couplings are necessary but not sufficient conditions to prove the CLAW hypothesis. C1 CSIC, ICM, Inst Ciencias Mar Barcelona, E-08003 Barcelona, Spain. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, GSFC, Baltimore, MD 20771 USA. UPMC, LODYC, Paris, France. CSIC, IIQAB, Dept Environm Chem, E-08034 Barcelona, Spain. RP Vallina, SM (reprint author), Univ E Anglia, Sch Environm Sci, Lab Global Marine & Atmospher Chem, Norwich NR4 7TJ, Norfolk, England. EM sergio.vallina@uea.ac.uk; rsimo@icm.sic.es; santiago@climate.gsfc.nasa.gov; clement@jamstec.go.jp; edelrio@cmima.csic.es; jurado.elena@gmail.com; jdmqam@cid.csic.es RI Jurado, Elena/B-3241-2009; de Boyer Montegut, Clement/F-9717-2010; Gasso, Santiago/H-9571-2014; OI Jurado, Elena/0000-0003-1444-2929; de Boyer Montegut, Clement/0000-0003-3218-9330; Gasso, Santiago/0000-0002-6872-0018; Dachs, Jordi/0000-0002-4237-169X NR 98 TC 32 Z9 32 U1 1 U2 21 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 EI 1944-9224 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD APR 19 PY 2007 VL 21 IS 2 AR GB2004 DI 10.1029/2006GB002787 PG 16 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 160OF UT WOS:000245951500001 ER PT J AU Clancy, RT Wolff, MJ Whitney, BA Cantor, BA Smith, MD AF Clancy, R. Todd Wolff, Michael J. Whitney, Barbara A. Cantor, Bruce A. Smith, Michael D. TI Mars equatorial mesospheric clouds: Global occurrence and physical properties from Mars Global Surveyor Thermal Emission Spectrometer and Mars Orbiter Camera limb observations SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID ENCIRCLING DUST STORM; WATER ICE CLOUDS; MARTIAN ATMOSPHERE; INTERANNUAL VARIABILITY; EXPLORATION ROVERS; MGS TES; CO2; ULTRAVIOLET; PATHFINDER; VIKING AB [ 1] We report the occurrence of a new type of cloud in the Mars dayside (1300 1400 Local Time) atmosphere, apparent as high-altitude ( 60 to 80 km), vertically discrete aerosol scattering layers. Mars Global Surveyor (MGS) limb observations from the Thermal Emission Spectrometer (TES) visible channel indicate peak frequencies at the beginning and end of the aphelion northern summer season (L-S = 30 degrees and 150 degrees), where they are confined to equatorial (15 degrees S - 15 degrees N) latitudes and two longitude ranges (40 degrees E - 2 degrees W and 50 degrees W - 120 degrees W). Limb images from the MGS Mars Orbiter Camera (MOC) indicate significant horizontal variations in these Mars equatorial mesospheric (MEM) clouds on 20 - 50 km scales. On the basis of the distribution of projected limb heights, MEM clouds exhibit peak optical depths over 70 - 75 km altitudes, that are substantial ( nadir tau(vis) of order 0.01) for the low-pressure region of formation ( similar to 1 mu bar). Averaged TES limb infrared spectral ( 5 - 40 mu m) and solarband radiance profiles corresponding to MEM occurrence indicate dust aerosols (r(eff) = 1.5 - 2.0 mu m, tau(vis) similar to 0.4) at 0 - 25 km altitudes, capped by water ice clouds (r(eff) = 1.5 - 2.0 mu m, tau(vis) similar to 0.2) at 20 - 45 km altitudes. The lack of detectable infrared radiances at MEM cloud heights precludes distinction of water versus CO2 ice, but indicates <= 1 mu m particle sizes for water or <= 1.5 mu m for CO2 ice compositions. More recent Mars Express observations point toward Mars mesospheric CO2 clouds, although current dynamical and radiative models do not indicate sufficiently cold temperatures at MEM cloud locations to produce daytime CO2 saturation conditions. C1 Space Sci Inst, Boulder, CO 80301 USA. Malin Space Sci Syst, San Diego, CA 92121 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Clancy, RT (reprint author), Space Sci Inst, 4750 Walnut St,Suite 205, Boulder, CO 80301 USA. EM clancy@spacescience.org RI Smith, Michael/C-8875-2012 NR 41 TC 32 Z9 32 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 19 PY 2007 VL 112 IS E4 AR E04004 DI 10.1029/2006JE002805 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 160OX UT WOS:000245953300001 ER PT J AU Koren, I Remer, LA Kaufman, YJ Rudich, Y Martins, JV AF Koren, Ilan Remer, Lorraine A. Kaufman, Yoram J. Rudich, Yinon Martins, J. Vanderlei TI On the twilight zone between clouds and aerosols SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CUMULUS CLOUDS; HUMIDITY; POLLUTION; CLIMATE; IMPACT; BRAZIL; SMOKE; HALOS; AIR AB Cloud and aerosols interact and form a complex system leading to high uncertainty in understanding climate change. To simplify this non-linear system it is customary to distinguish between "cloudy'' and "cloud-free'' areas and measure them separately. However, we find that clouds are surrounded by a "twilight zone'' - a belt of forming and evaporating cloud fragments and hydrated aerosols extending tens of kilometers from the clouds into the so-called cloud-free zone. The gradual transition from cloudy to dry atmosphere is proportional to the aerosol loading, suggesting an additional aerosol effect on the composition and radiation fluxes of the atmosphere. Using AERONET data, we find that the measured aerosol optical depth is higher by 13% +/- 2% in the visible and 22% +/- 2% in the NIR in measurements taken near clouds relative to its value in the measurements taken before or after, and that 30% - 60% of the free atmosphere is affected by this phenomenon. C1 Weizmann Inst Sci, Dept Environm Sci, IL-76100 Rehovot, Israel. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21228 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. RP Koren, I (reprint author), Weizmann Inst Sci, Dept Environm Sci, IL-76100 Rehovot, Israel. EM ilan.koren@weizmann.ac.il RI Rudich, Yinon/K-1498-2012; Koren, Ilan/K-1417-2012; OI Koren, Ilan/0000-0001-6759-6265; Rudich, Yinon/0000-0003-3149-0201 NR 17 TC 156 Z9 157 U1 0 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 18 PY 2007 VL 34 IS 8 AR L08805 DI 10.1029/2007GL029253 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 160OA UT WOS:000245951000004 ER PT J AU Hudman, RC Jacob, DJ Turquety, S Leibensperger, EM Murray, LT Wu, S Gilliland, AB Avery, M Bertram, TH Brune, W Cohen, RC Dibb, JE Flocke, FM Fried, A Holloway, J Neuman, JA Orville, R Perring, A Ren, X Sachse, GW Singh, HB Swanson, A Wooldridge, PJ AF Hudman, R. C. Jacob, D. J. Turquety, S. Leibensperger, E. M. Murray, L. T. Wu, S. Gilliland, A. B. Avery, M. Bertram, T. H. Brune, W. Cohen, R. C. Dibb, J. E. Flocke, F. M. Fried, A. Holloway, J. Neuman, J. A. Orville, R. Perring, A. Ren, X. Sachse, G. W. Singh, H. B. Swanson, A. Wooldridge, P. J. TI Surface and lightning sources of nitrogen oxides over the United States: Magnitudes, chemical evolution, and outflow SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPICAL TROPOSPHERIC OZONE; AIRCRAFT NOX EMISSIONS; REACTIVE NITROGEN; NORTH-AMERICA; GLOBAL DISTRIBUTION; MODEL DESCRIPTION; BOUNDARY-LAYER; TRANSPORT; DISTRIBUTIONS; CHEMISTRY AB [1] We use observations from two aircraft during the ICARTT campaign over the eastern United States and North Atlantic during summer 2004, interpreted with a global 3-D model of tropospheric chemistry (GEOS-Chem) to test current understanding of regional sources, chemical evolution, and export of NOx. The boundary layer NOx data provide top-down verification of a 50% decrease in power plant and industry NOx emissions over the eastern United States between 1999 and 2004. Observed NOx concentrations at 8 - 12 km altitude were 0.55 +/- 0.36 ppbv, much larger than in previous U. S. aircraft campaigns (ELCHEM, SUCCESS, SONEX) though consistent with data from the NOXAR program aboard commercial aircraft. We show that regional lightning is the dominant source of this upper tropospheric NOx and increases upper tropospheric ozone by 10 ppbv. Simulating ICARTT upper tropospheric NOx observations with GEOS-Chem requires a factor of 4 increase in modeled NOx yield per flash ( to 500 mol/ flash). Observed OH concentrations were a factor of 2 lower than can be explained from current photochemical models, for reasons that are unclear. A NOy-CO correlation analysis of the fraction f of North American NOx emissions vented to the free troposphere as NOy ( sum of NOx and its oxidation products) shows observed f = 16 +/- 10% and modeled f = 14 +/- 9%, consistent with previous studies. Export to the lower free troposphere is mostly HNO3 but at higher altitudes is mostly PAN. The model successfully simulates NOy export efficiency and speciation, supporting previous model estimates of a large U. S. anthropogenic contribution to global tropospheric ozone through PAN export. C1 Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. US EPA, Air Resources Lab, Atmospher Sci Modeling Div, NOAA, Res Triangle Pk, NC 27711 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. Univ Calif Berkeley, Coll Chem, Berkeley, CA 94720 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Natl Ctr Atmospher Res, Earth Observing Lab, Boulder, CO 80307 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NOAA, Earth Syst Res Lab, Boulder, CO USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Hudman, RC (reprint author), Harvard Univ, Dept Earth & Planetary Sci, 20 Oxford St, Cambridge, MA 02138 USA. EM rch@io.harvard.edu RI Holloway, John/F-9911-2012; Cohen, Ronald/A-8842-2011; Chem, GEOS/C-5595-2014; Ren, Xinrong/E-7838-2015; Manager, CSD Publications/B-2789-2015; Perring, Anne/G-4597-2013; Ren, Xinrong/B-2229-2010; Hudman, Rynda/C-6118-2009; Orville, Richard/G-9866-2012; Neuman, Andy/A-1393-2009; Murray, Lee/F-2296-2014 OI Holloway, John/0000-0002-4585-9594; Cohen, Ronald/0000-0001-6617-7691; Ren, Xinrong/0000-0001-9974-1666; Perring, Anne/0000-0003-2231-7503; Orville, Richard/0000-0003-0280-7169; Neuman, Andy/0000-0002-3986-1727; Murray, Lee/0000-0002-3447-3952 NR 69 TC 174 Z9 176 U1 3 U2 34 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 18 PY 2007 VL 112 IS D12 AR D12S05 DI 10.1029/2006JD007912 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 160OL UT WOS:000245952100001 ER PT J AU Matichuk, RI Colarco, PR Smith, JA Toon, OB AF Matichuk, R. I. Colarco, P. R. Smith, J. A. Toon, O. B. TI Modeling the transport and optical properties of smoke aerosols from African savanna fires during the Southern African Regional Science Initiative campaign (SAFARI 2000) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID REMOTE-SENSING OBSERVATIONS; SAHARAN DUST TRANSPORT; FOREST-FIRE; IMAGING SPECTRORADIOMETER; TROPOSPHERIC AEROSOL; TRACE GASES; DRY SEASON; IN-SITU; ART.; SIMULATIONS AB [1] We investigate the transport and optical properties of smoke aerosols from southern Africa using an offline three-dimensional aerosol transport model. We use Sun photometer retrieved particle size distributions and monthly mean satellite-derived smoke emissions as input parameters. We find that using these observations in our model allows us to reproduce the measured optical properties collected during the Southern African Regional Science Initiative campaign ( SAFARI 2000). In particular, we find day-to-day oscillations in the simulated aerosol optical thickness (AOT) similar to Aerosol Robotic Network (AERONET) retrievals, suggesting that variations in aerosol loading are controlled more by transport processes than fluctuations in smoke emissions. We also find that the simulated AOT, Angstrom exponent, and single scattering albedo compare well to AERONET. The model and satellite observations from the Moderate Resolution Imaging Spectroradiometer ( MODIS) and the Multiangle Imaging Spectroradiometer (MISR) also show that the dominant transport of smoke plumes over Africa was westward during September 2000. However, the satellite observations show higher AOT values than our model over the Atlantic Ocean. These higher values observed by the satellites may be a result of poor single scattering assumptions and the contamination by subpixel clouds in the retrievals. However, the monthly mean smoke emissions may also be too low, resulting in low simulated AOT values. We also find discrepancies between MODIS and MISR, which limit our ability to use the satellite data to validate our model. Our work suggests strategies for improving the treatment of smoke aerosols from African biomass burning in climate and microphysical models. C1 Univ Colorado, Dept Atmospher & Ocean Sci, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Matichuk, RI (reprint author), Univ Colorado, Dept Atmospher & Ocean Sci, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. EM rebecca.matichuk@lasp.colorado.edu RI Colarco, Peter/D-8637-2012 OI Colarco, Peter/0000-0003-3525-1662 NR 56 TC 26 Z9 26 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 18 PY 2007 VL 112 IS D8 AR D08203 DI 10.1029/2006JD007528 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 160OH UT WOS:000245951700001 ER PT J AU Prasad, TG Hogan, PJ AF Prasad, T. G. Hogan, Patrick J. TI Upper-ocean response to Hurricane Ivan in a 1/25 degrees nested Gulf of Mexico HYCOM SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID MIXED-LAYER RESPONSE; VERTICAL DIFFUSIVITIES; CLOSURE-MODEL; TURBULENCE; WATER; COORDINATE; EQUATIONS; MOMENTUM; GILBERT; RINGS AB [ 1] A 20-layer, 1/25 degrees nested Gulf of Mexico (GoM) Hybrid Coordinate Ocean Model (HYCOM) has been employed to examine the evolving three-dimensional ocean response to Hurricane Ivan during 14 - 16 September 2004. Results from several combinations of numerical experiments with and without assimilation of satellite-altimetry sea-surface height (SSH) are being analyzed and compared for the September 2004 hurricane period. A comparison of simulated zonal and meridional velocities using data assimilation shows improved agreement with profiler observations. The amplitude of the cold wake ( similar to 6 degrees C) produced by these simulations compared reasonably well with the observed changes in SST before and after the storm; however, the region of extreme cooling varied depending on the simulated location of the warm core eddy (WCE) that had detached from the Loop Current ( LC). While the simulated location of the WCE and LC in the assimilation runs agree better with satellite altimetry, the storm-induced SST cooling was 40% - 50% greater than the observed cooling. Overall, similar to 64% of the cooling was due to vertical mixing caused by turbulence generated from strong shear-stress across the base of the mixed layer. Vertical advection (upwelling) caused a significant portion of cooling (23.4%) in those runs that included data assimilation; a three fold increase from the nonassimilative runs (7%). This enhanced upper- ocean cooling was caused primarily by the prestorm thermal stratification; a shallower thermocline ( similar to 40 m) and a stronger upper- thermocline temperature gradient compared with the nonassimilative runs. In all the experiments the air-sea exchange was a small component of the mixed-layer heat budget which overall accounted for similar to 4% C1 USN, Res Lab, Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. Univ So Mississippi, Dept Marine Sci, Stennis Space Ctr, Mississippi State, MS USA. RP Prasad, TG (reprint author), USN, Res Lab, Stennis Space Ctr, Code 7323, Stennis Space Ctr, MS 39529 USA. EM thoppil@nrlssc.navy.mil NR 40 TC 38 Z9 41 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD APR 18 PY 2007 VL 112 IS C4 AR C04013 DI 10.1029/2006JC003695 PG 18 WC Oceanography SC Oceanography GA 160OT UT WOS:000245952900001 ER PT J AU Bleacher, JE Greeley, R Williams, DA Werner, SC Hauber, E Neukum, G AF Bleacher, Jacob E. Greeley, Ronald Williams, David A. Werner, Stephanie C. Hauber, Ernst Neukum, Gerhard TI Olympus Mons, Mars: Inferred changes in late Amazonian aged effusive activity from lava flow mapping of Mars Express High Resolution Stereo Camera data SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID ORBITER LASER ALTIMETER; KILAUEA VOLCANO; MARTIAN VOLCANOS; THARSIS REGION; ARSIA MONS; MAUNA-ULU; MOLA DATA; MORPHOLOGY; TUBES; ERUPTION AB [ 1] Lava flow mapping was conducted on a north-south transect of Olympus Mons using the European Space Agency's Mars Express High Resolution Stereo Camera (HRSC) image H0037. The HRSC image was coregistered to Mars Orbiter Laser Altimeter, Thermal Emission Imaging System, and Mars Orbiter Camera data, enabling lava flow structures to be differentiated and mapped consistently across the shield. Because different structures develop as a result of different effusive conditions, their abundance and distribution provide insight into the eruptive history of a shield volcano. Results show that lava channels are the dominant flow structure, whereas tabular sheets are most common beyond the basal scarp. A hummocky unit dominates the summit area and likely represents a combination of ( 1) volcanic lava flows, ( 2) pyroclastic deposits, ( 3) a dust mantle, and ( 4) frozen volatiles, all of which have been suggested to exist on Olympus Mons in the past. Lava fans are typically associated with lava tubes, indicating that they represent tube outbreaks as was previously suggested as one possible formation mechanism. No vents were identified, suggesting that major rift zones have not developed on the north or south flank. Younger channel-fed flows typically embay older tube-related flows, which they outnumber by a ratio of 5: 1. Therefore Olympus Mons likely experienced a change in eruptive style from longer-lived, stable, tube-forming eruptions to shorter-lived, less stable, channel-forming eruptions in the late Amazonian. A similar trend exists for the Hawaiian volcanoes in which a decrease in the magma production rate drives a change to dominantly channel forming eruptions associated with increased shield age. C1 Arizona State Univ, Sch Earth & Space Explorat, Tempe, AZ 85287 USA. Free Univ Berlin, Inst Geol Sci, D-12249 Berlin, Germany. German Aerosp Ctr, DLR, Inst Planetary Res, D-12489 Berlin, Germany. RP Bleacher, JE (reprint author), NASA, Goddard Space Flight Ctr, Planetary & Geodynam Lab, Code 698,Bldg 33,Room G310, Greenbelt, MD 20771 USA. EM jake@puuoo.gsfc.nasa.gov RI Werner, Stephanie/A-6438-2012; Bleacher, Jacob/D-1051-2012 OI Werner, Stephanie/0000-0001-5704-0909; Bleacher, Jacob/0000-0002-8499-4828 NR 80 TC 23 Z9 23 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 18 PY 2007 VL 112 IS E4 AR E04003 DI 10.1029/2006JE002826 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 160OW UT WOS:000245953200001 ER PT J AU Forbes, JM Konopliv, A AF Forbes, J. M. Konopliv, A. TI Oscillation of Venus' upper atmosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PLANETARY-SCALE WAVES; LOWER THERMOSPHERE; SPACED DATA; VARIABILITY; MESOSPHERE; DYNAMICS; GRAVITY; MODEL AB Little is known about the variability of Venus' upper atmosphere. We report discovery of a large (similar to +/- 30 - 50%) 9-day period density oscillation, derived from radar tracking of the Magellan spacecraft from 15 Sept 92 - 24 May 93. The densities correspond to 164 - 184 km altitude, 11 degrees N latitude, and cover all local times. The wave is presumed to propagate upward from lower atmosphere regions, and occurs mainly between dusk and midnight, suggesting that local time differences in forcing and/or mean wind filtering are affecting accessibility to the upper atmosphere. Possible sources for the wave are discussed, including wave-wave interactions. Many questions remain concerning the origin and nature of the 9-day oscillation, including its persistence. Instruments on Venus Express, now orbiting Venus, have the opportunity to further elucidate the 9-day wave and understand its role in the dynamics of Venus' upper atmosphere. C1 Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Forbes, JM (reprint author), Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. EM forbes@colorado.edu; alex.konopliv@jpl.nasa.gov OI FORBES, JEFFREY/0000-0001-6937-0796 NR 23 TC 7 Z9 7 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 17 PY 2007 VL 34 IS 8 AR L08202 DI 10.1029/2007GL029252 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 160NZ UT WOS:000245950900007 ER PT J AU Li, JL Jiang, JH Waliser, DE Tompkins, AM AF Li, J. -L. Jiang, J. H. Waliser, D. E. Tompkins, A. M. TI Assessing consistency between EOS MLS and ECMWF analyzed and forecast estimates of cloud ice SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GENERAL-CIRCULATION MODEL; DIURNAL CYCLE; CIRRUS CLOUDS; PRECIPITATION; CLIMATE; SYSTEM; SATELLITE; RADIANCES; RADIATION; FLUXES AB Cloud ice water content (IWC) from MLS retrievals and ECMWF analyses and forecasts are compared for August 2004 to July 2005. ECMWF data are sampled along MLS tracks and filtered according to MLS sensitivity. At 147 hPa, there is good spatial agreement with the analyses biased high by 10%. Over landmasses, the analyses are biased low up to 50%. This underestimation grows in the forecasts, with a 40% reduction by day 10. At 215 hPa, the analyses are biased low by 10 - 60%. However, at this level the forecast IWC undergoes little change. These biases, in conjunction with those in precipitation and top of the atmosphere radiative fluxes, along with consideration of the changes in vertical velocity, cumulus cloud mass flux and cloud top detrainment, indicates a systematic reduction of the modeled deep convection over the warm pool in conjunction with a weakened large-scale circulation and enhanced upper-level vertical stratification. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. European Ctr Medium Range Weather Forecasts, Reading RG1 1NT, Berks, England. RP Li, JL (reprint author), CALTECH, Jet Prop Lab, MS 183-601,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM jli@jpl.nasa.gov RI Tompkins, Adrian/N-6472-2013 OI Tompkins, Adrian/0000-0003-0975-6691 NR 25 TC 21 Z9 22 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 17 PY 2007 VL 34 IS 8 AR L08701 DI 10.1029/2006GL029022 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 160NZ UT WOS:000245950900003 ER PT J AU Treiman, AH Dyar, MD McCanta, M Noble, SK Pieters, CM AF Treiman, Allan H. Dyar, M. Darby McCanta, Molly Noble, Sarah K. Pieters, Carle M. TI Martian Dunite NWA 2737: Petrographic constraints on geological history, shock events, and olivine color SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID OXYGEN FUGACITY; UPPER-MANTLE; OXIDATION-STATE; ELECTRON-MICROPROBE; ORDINARY CHONDRITES; CRYSTAL-CHEMISTRY; METEORITE; CHASSIGNY; SPINELS; PETROGENESIS AB [ 1] Meteorite Northwest Africa (NWA) 2737 is the second known chassignite, an olivine-rich igneous rock with mineral compositions and isotopic ratios that suggest it formed on Mars. NWA 2737 consists of similar to 85% vol. olivine (Mg#, molar Mg/(Mg + Fe), of 78.3 +/- 0.4%), which is notable because it is black in hand sample and brown in thin section. Other minerals include chromite, pyroxenes (augite, pigeonite, orthopyroxene), and diaplectic glass of alkali-feldspar composition. Aqueous alteration is minimal and appears only as slight dissolution of glass. NWA 2737 formed by accumulation of olivine and chromite from a basaltic magma; the other minerals represent magma trapped among the cumulus grains. Minerals are compositionally homogeneous, consistent with chemical equilibration in late and postigneous cooling. Two-pyroxene thermometry gives equilibration temperatures similar to 1150 degrees C, implying a significant time spent at the basalt solidus. Olivine-spinel-pyroxene equilibria give similar to 825 degrees C ( possibly the T of mesostasis crystallization) at an oxidation state of similar to QMF-1. This oxidation state is consistent with low Fe3+ in olivine ( determined by EMP, Mossbauer spectra, and synchrotron micro-XANES spectroscopy) and with similar to 10% of the iron in pyroxene being Fe3+. NWA 2737 experienced two shock events. The first shock, to stage S5 - S6, affected the olivine by producing in it planar deformation features, intense mosaicism and lattice strain, and abundant droplets of iron-nickel metal, 5 - 15 nm in diameter. At this stage the olivine became deeply colored, i.e., strongly absorbing at visible and near-infrared (NIR) wavelengths. This shock event and its thermal pulse probably occurred at similar to 170 Ma, the Ar-Ar age of NWA 2737. The colored olivine is cut by ribbons of coarser, uncolored olivine with long axes along [ 100] and shorter axes on {021} planes: These are consistent with the easy slip law for olivine [ 100]{021}, which is activated at moderate strain rate at high temperature. Within these ribbons the olivine was coarsened and the iron metal globules coalesced to micron-sized grains. The ribbons also are mosaicized and cut by planar fractures, which bespeak a second shock event, possibly that of ejection from Mars. The deeply colored olivine in NWA 2737 is unusual and represents a new "ground truth'' type for remote sensing of Mars. Understanding the occurrence of the brown color in olivine in NWA 2737 places important constraints on interpretation of optical measurements. C1 Lunar & Planetary Inst, Houston, TX 77058 USA. Mt Holyoke Coll, Dept Astron, S Hadley, MA 01075 USA. Lyndon B Johnson Space Ctr, ARES Div, Houston, TX 77058 USA. Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. RP Treiman, AH (reprint author), Lunar & Planetary Inst, 3600 Bay Area Blvd, Houston, TX 77058 USA. EM treiman@lpi.usra.edu RI Noble, Sarah/D-7614-2012 NR 96 TC 34 Z9 34 U1 0 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 17 PY 2007 VL 112 IS E4 AR E04002 DI 10.1029/2006JE002777 PG 20 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 160OV UT WOS:000245953100001 ER PT J AU Eddy, CR Holm, RT Henry, RL Twigg, ME Bassim, ND Shirey, LM Glembocki, OJ Culbertson, JC Perkins, FK Peckerar, MC Ngu, Y Yan, F AF Eddy, C. R., Jr. Holm, R. T. Henry, R. L. Twigg, M. E. Bassim, N. D. Shirey, L. M. Glembocki, O. J. Culbertson, J. C. Perkins, F. K. Peckerar, M. C. Ngu, Y. Yan, F. TI Improved GaN materials and devices through confined epitaxy SO APPLIED PHYSICS LETTERS LA English DT Article ID SELECTIVE GROWTH; SUBSTRATE; SILICON; FILMS; MOVPE AB An approach to reduce vertical threading dislocations in the active regions of III-nitride devices is described. The approach involves confined homo- or heteroepitaxy of GaN materials using sputtered oxide masks to delineate growth regions and conventional metal-organic chemical vapor deposition. The resulting confined epitaxial material is terminated with equilibrium crystal facets, which form hexagonal mesas, and contains a reduced dislocation density and reduced strain compared to the underlying template layer for homoepitaxial growth. Characterization of pn junction diodes grown with this approach reveals significantly reduced leakage currents in as-grown, unpassivated structures (as low as 1x10(-7) A cm(-2)). C1 USN, Res Lab, Div Elect Sci & Technol, Washington, DC 20375 USA. Univ Maryland, Dept Elect Engn, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Eddy, CR (reprint author), USN, Res Lab, Div Elect Sci & Technol, 4555 Overlook Ave SW, Washington, DC 20375 USA. EM charles.eddy@nrl.navy.mil RI Shirey, Loretta/B-3164-2013 OI Shirey, Loretta/0000-0003-2600-3405 NR 14 TC 4 Z9 4 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 16 PY 2007 VL 90 IS 16 AR 162101 DI 10.1063/1.2724773 PG 3 WC Physics, Applied SC Physics GA 159MP UT WOS:000245870400055 ER PT J AU Bloemhof, EE AF Bloemhof, E. E. TI Feasibility of symmetry-based speckle noise reduction for faint companion detection SO OPTICS EXPRESS LA English DT Article ID POINT-SPREAD FUNCTION; REMNANT SPECKLES; ADAPTIVE OPTICS; CORONAGRAPH; RATIO AB Great interest has been focused on the problem of detecting faint companions, possibly including extrasolar planets, very close to other stars. A promising approach involves coupling high-correction adaptive optics to coronagraphs, for which many new and innovative designs have emerged. Detection of faint companions will require suppression of noise due to fluctuating speckles from the remnant fraction of stellar light not adaptively controlled. At high correction, the speckle halo takes on distinct spatial symmetries that may allow partial speckle noise reduction through relatively simple post-processing that rejects one spatial symmetry in the image. This paper quantitatively examines potential companion-detection sensitivity improvements that might be expected, and shows that realistic operational parameters will allow them to be realized. (c) 2007 Optical Society of America C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bloemhof, EE (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. EM Eric.E.Bloemhof@jpl.nasa.gov NR 19 TC 1 Z9 1 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD APR 16 PY 2007 VL 15 IS 8 BP 4705 EP 4710 DI 10.1364/OE.15.004705 PG 6 WC Optics SC Optics GA 158HN UT WOS:000245782500030 PM 19532716 ER PT J AU Mohageg, M Savchenkov, A Maleki, L AF Mohageg, Makan Savchenkov, Anatoliy Maleki, Lute TI High-Q optical whispering gallery modes in elliptical LiNbO3 resonant cavities SO OPTICS EXPRESS LA English DT Article ID MICROCAVITY; FILTER AB We have experimentally demonstrated the existence of optical whispering-gallery-modes (WGMs) with quality factors in excess of 108 in elliptical cavities fabricated with LiNbO3. The efficiency of evanescent coupling to the modes through a diamond prism was as high as 97.3%. This is the best value ever achieved for evanescent coupling to a WGM resonator using a prism. The free spectral ranges of the WGMs are successfully modeled using an eikonal approximation. (c) 2007 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mohageg, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM makan.mohageg@jpl.nasa.gov NR 22 TC 9 Z9 10 U1 4 U2 12 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD APR 16 PY 2007 VL 15 IS 8 BP 4869 EP 4875 DI 10.1364/OE.15.004869 PG 7 WC Optics SC Optics GA 158HN UT WOS:000245782500048 PM 19532734 ER PT J AU Rankenburg, K Brandon, AD Norman, MD AF Rankenburg, K. Brandon, A. D. Norman, M. D. TI A Rb-Sr and Sm-Nd isotope geochronology and trace element study of lunar meteorite LaPaz Icefield 02205 SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID HF-W CHRONOMETRY; PROCELLARUM KREEP TERRANE; MARE-BASALT METEORITE; PRECISE DETERMINATION; THORIUM ABUNDANCES; MOON; EVOLUTION; SURFACE; MANTLE; GEOCHEMISTRY AB Rubidium-strontium and samarium-neodymium isotopes of lunar meteorite LaPaz Icefield (LAP) 02205 are consistent with derivation of the parent magma from a source region similar to that which produced the Apollo 12 low-Ti olivine basalts followed by mixing of the magma with small amounts (1-2 wt%) of trace element-enriched material similar to lunar KREEP-rich sample SaU 169. The crystallization age of LAP 02205 is most precisely dated by an internal Rb-Sr isochron of 2991 +/- 14 Ma, with an initial Sr-87/Sr-88 at the time of crystallization of 0.699836 +/- 0.000010. Leachable REE-rich phosphate phases of LAP 02205 do not plot on a Sm-Nd mineral isochron, indicating contamination or open system behavior of the phosphates. Excluding anomalous phases from the calculation of a Sm-Nd isochron yields a crystallization age of 2992 85 (initial g(143)Nd = +2.9 +/- 0.8) that is within error of the Rb-Sr age, and in agreement with other independent age determinations for LAP 02205 from Ar-Ar and U-Pb methods. The calculated Sm-147/Nd-144 source ratios for LAP 02205, various Apollo 12 and 15 basalts, and samples with strong affinities to KREEP (SaU 169, NWA 773, 15386) are uncorrelated with their crystallization ages. This finding does not support the involvement of a common KREEP component as a heat source for lunar melting events that occurred after crystallization of the lunar magma ocean. (c) 2007 Elsevier Ltd. All rights reserved. C1 Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. Florida State Univ, Dept Geol Sci, Tallahassee, FL 32310 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT 0200, Australia. Lunar & Planetary Inst, Houston, TX 77058 USA. RP Rankenburg, K (reprint author), Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. EM rankenburg@magnet.fsu.edu RI Norman, Marc/A-2244-2008 NR 64 TC 20 Z9 20 U1 1 U2 15 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD APR 15 PY 2007 VL 71 IS 8 BP 2120 EP 2135 DI 10.1016/j.gca.2007.01.014 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 159JA UT WOS:000245860500016 ER PT J AU Johnson, PV Beegle, LW Kim, HI Eiceman, GA Kanik, I AF Johnson, Paul V. Beegle, Luther W. Kim, Hugh I. Eiceman, Gary A. Kanik, Isik TI Ion mobility spectrometry in space exploration SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Review DE ion mobility spectrometry; space exploration; Mars; NASA; organic compounds ID PRESSURE CHEMICAL-IONIZATION; VOLATILE ORGANIC-COMPOUNDS; ELECTROSPRAY-IONIZATION; GAS-CHROMATOGRAPHY; MASS-SPECTROMETRY; MERIDIANI-PLANUM; AMINO-ACIDS; COMETARY DELIVERY; DEEP SUBSURFACE; CLUSTER IONS AB Ion mobility spectrometry (IMS) has proven to be an effective tool for chemical detection and identification. Ion mobility spectrometers can be manufactured in small, rugged and portable designs and have been used in several mission critical circumstances from security screening and military preparedness. Perhaps most visible are the IMS analyzers that have been deployed in airports around the world to detect traces of explosives on passenger carry-on luggage. Intrinsic properties of ion mobility spectrometers make these analyzers suitable for both manned and robotic space exploration. In this review, we will discuss the utility, previous use and future use of ion mobility spectrometers in space environments. (C) 2006 Elsevier B.V. All rights reserved. C1 [Johnson, Paul V.; Beegle, Luther W.; Kim, Hugh I.; Kanik, Isik] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Kim, Hugh I.] CALTECH, Arthur Amos Noyes Lab Chem Phys, Pasadena, CA 91125 USA. [Eiceman, Gary A.] New Mexico State Univ, Dept Chem & Biochem, Las Cruces, NM 88003 USA. RP Johnson, PV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Paul.V.Johnson@jpl.nasa.gov; Luther.Beegle@jpl.nasa.gov; Hugh.I.Kim@jpl.nasa.gov; geiceman@nmsu.edu; Isik.Kanik@jpl.nasa.gov RI Beegle, Luther/A-6354-2010; Kim, Hugh/G-4476-2011; Johnson, Paul/D-4001-2009 OI Johnson, Paul/0000-0002-0186-8456 NR 122 TC 18 Z9 21 U1 3 U2 25 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 EI 1873-2798 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD APR 15 PY 2007 VL 262 IS 1-2 BP 1 EP 15 DI 10.1016/j.ijms.2006.11.001 PG 15 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 152SJ UT WOS:000245381800001 ER PT J AU Lynn, BH Healy, R Druyan, LM AF Lynn, Barry H. Healy, Richard Druyan, Leonard M. TI An analysis of the potential for extreme temperature change based on observations and model simulations SO JOURNAL OF CLIMATE LA English DT Article ID WESTERN UNITED-STATES; CONVECTIVE ADJUSTMENT SCHEME; REGIONAL CLIMATE SIMULATION; SURFACE-HYDROLOGY MODEL; PART I; US PRECIPITATION; EVENTS; CIRCULATION; SENSITIVITY; ANOMALIES AB The study analyzes observational climate data for June - August 1977 - 2004 and simulations of current and future climate scenarios from a nested GCM/ regional climate model system to assess the potential for extreme temperature change over the eastern United States. Observational evidence indicates that anomalously warm summers in the eastern United States coincide with anomalously cool eastern Pacific sea surface temperatures, conditions that are conducive to geopotential ridging over the east, less frequent precipitation, and lower accumulated rainfall. The study also found that days following nighttime rain are warmer on average than daytime rain events, emphasizing the importance of the timing of precipitation on the radiation balance. Precipitation frequency and eastern Pacific sea surface temperature anomalies together account for 57% of the 28- yr variance in maximum surface temperature anomalies. Simulation results show the sensitivity of maximum surface air temperature to the moist convection parameterization that is employed, since different schemes produce different diurnal cycles and frequencies of precipitation. The study suggests that, in order to accurately project scenarios of extreme temperature change, models need to realistically simulate changes in the surface energy balance caused by the interannual variation of these precipitation characteristics. The mesoscale model that was realistic in this respect predicted much warmer mean and maximum surface air temperatures for five future summers than the parallel GCM driving simulation. C1 Columbia Univ, Ctr Climate Syst Res, New York, NY 10025 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. RP Druyan, LM (reprint author), Columbia Univ, Ctr Climate Syst Res, 2880 Broadway, New York, NY 10025 USA. EM LD12@columbia.edu RI Healy, Richard/J-9214-2015 OI Healy, Richard/0000-0002-5098-8921 NR 39 TC 15 Z9 15 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD APR 15 PY 2007 VL 20 IS 8 BP 1539 EP 1554 DI 10.1175/JCLI4219.1 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 157SY UT WOS:000245742400008 ER PT J AU Moision, B Orlitsky, A Siegel, PH AF Moision, Bruce Orlitsky, Alon Siegel, Paul H. TI On codes with local joint constraints SO LINEAR ALGEBRA AND ITS APPLICATIONS LA English DT Article DE joint spectral radius; generalized spectral radius; infonnation capacity; forbidden words ID GENERALIZED SPECTRAL-RADIUS; INFINITE PRODUCTS; RECORDING-SYSTEMS; MATRICES; SET AB We study the largest number of sequences with the property that any two sequences do not contain specified pairs of patterns. We show that this number increases exponentially with the length of the sequences and that the exponent, or capacity, is the logarithm of the joint spectral radius of an appropriately defined set of matrices. We illustrate a new heuristic for computing the joint spectral radius and use it to compute the capacity for several simple collections. The problem of computing the achievable rate region of a collection of codes is introduced and it is shown that the region may be computed via a similar analysis. (c) 2006 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA. Univ Calif San Diego, Ctr Magnet Recording Res, La Jolla, CA 92093 USA. RP Moision, B (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 238-420, Pasadena, CA 91109 USA. EM bmoision@jpl.nasa.gov; alon@ece.ucsd.edu; psiegel@ucsd.edu NR 23 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0024-3795 J9 LINEAR ALGEBRA APPL JI Linear Alg. Appl. PD APR 15 PY 2007 VL 422 IS 2-3 BP 442 EP 454 DI 10.1016/j.laa.2006.11.002 PG 13 WC Mathematics, Applied; Mathematics SC Mathematics GA 158HO UT WOS:000245782600007 ER PT J AU Singh, M Asthana, R Shpargel, TP AF Singh, M. Asthana, R. Shpargel, T. P. TI Brazing of carbon-carbon composites to Cu-clad molybdenum for thermal management applications SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE carbon-carbon composites; brazing; copper-clad molybdenum; microstructure; microhardness ID TITANIUM AB Advanced carbon-carbon composites were joined to copper-clad molybdenum (Cu/Mo) using four active metal brazes containing Ti (Cu-ABA, Cusin-1 ABA, Ticuni, and Ticusil) for potential use in thermal management applications. The brazed joints were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Knoop microhardness measurements across the joint region. Metallurgically sound C-C/Cu/Mo joints, devoid of interfacial cracks formed in all cases. The joint interfaces were preferentially enriched in Ti, with Cu-ABA joints exhibiting the largest interfacial Ti concentrations. The microhardness measurements revealed hardness gradients across the joint region, with a peak hardness of 300-350 KHN in Cusin-1 ABA and Ticusil joints and 200-250 KHN in Cu-ABA and Ticuni joints, respectively. (c) 2006 Elsevier B.V. All rights reserved. C1 NASA, Glenn Res Ctr, Ohio Aerospace Inst, Cleveland, OH 44135 USA. Univ Wisconsin Stout, Dept Engn & Technol, Menomonie, WI 54751 USA. NASA, Glenn Res Ctr, Qss Grp Inc, Cleveland, OH 44135 USA. RP Singh, M (reprint author), NASA, Glenn Res Ctr, Ohio Aerospace Inst, Cleveland, OH 44135 USA. EM Mrityunjay.Singh@grc.nasa.gov NR 16 TC 34 Z9 37 U1 3 U2 10 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD APR 15 PY 2007 VL 452 BP 699 EP 704 DI 10.1016/j.msea.2006.11.031 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 156HX UT WOS:000245639800094 ER PT J AU Pena, J Hinchey, MG Resinas, M Sterritt, R Rash, JL AF Pena, Joaquin Hinchey, Michael G. Resinas, Manuel Sterritt, Roy Rash, James L. TI Designing and managing evolving systems using a MAS product line approach SO SCIENCE OF COMPUTER PROGRAMMING LA English DT Article; Proceedings Paper CT 5th International Workshop on System/Software Architectures (IWSSA 2006) CY JUN 27, 2006 CL Las Vegas, NV DE multiagent systems product lines; enterprise architecture evolution; swarm-based systems ID IMPLEMENTATION AB We view an evolutionary system as being a software product line. The core architecture is the unchanging part of the system, and each version of the system may be viewed as a product from the product line. Each "product" may be described as the core architecture with some agent-based additions. The result is a multiagent system software product line. We describe an approach to such a software product line-based approach using the MaCMAS agent-oriented methodology. The approach scales to enterprise architectures as a multiagent system is an appropriate means of representing a changing enterprise architecture and the interaction between components in it. In addition, we reduce the gap between the enterprise architecture and the software architecture. (C) 2007 Elsevier B.V. All rights reserved. C1 Univ Seville, ETSI Informat, Dpto Lenguajes & Sistemas Informat, E-41012 Seville, Spain. NASA, Goddard Space Flight Ctr, Informat Syst Div, Greenbelt, MD 20771 USA. Univ Ulster, Sch Comp & Math, Fac Engn, Jordanstown BT37 0QB, North Ireland. RP Pena, J (reprint author), Univ Seville, ETSI Informat, Dpto Lenguajes & Sistemas Informat, Avda Reina Mercedes S-N, E-41012 Seville, Spain. EM joaquinp@us.es; Michael.G.Hinchey@nasa.gov; resinas@us.es; r.sterritt@ulster.ac.uk; James.L.Rash@nasa.gov RI Resinas, Manuel/B-3063-2008; Pena, Joaquin /K-8217-2012 OI Resinas, Manuel/0000-0003-1575-406X; Pena, Joaquin /0000-0001-9216-9695 NR 21 TC 7 Z9 7 U1 1 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-6423 EI 1872-7964 J9 SCI COMPUT PROGRAM JI Sci. Comput. Program. PD APR 15 PY 2007 VL 66 IS 1 BP 71 EP 86 DI 10.1016/j.scico.2006.10.007 PG 16 WC Computer Science, Software Engineering SC Computer Science GA 168GO UT WOS:000246511500006 ER PT J AU Smith, AK Pancheva, DV Mitchell, NJ Marsh, DR Russell, JM Mlynczak, MG AF Smith, Anne K. Pancheva, Dora V. Mitchell, Nicholas J. Marsh, Daniel R. Russell, James M., III Mlynczak, Martin G. TI A link between variability of the semidiurnal tide and planetary waves in the opposite hemisphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID WIND; TEMPERATURE; ATMOSPHERE; MESOSPHERE; NORTHERN AB Horizontal wind observations over four years from the meteor radar at Esrange (68 degrees N, 21 degrees E) are analyzed to determine the variability of the semidiurnal tide. Simultaneous global observations of temperature and geopotential from the SABER satellite instrument are used to construct time series of planetary wave amplitudes and geostrophic mean zonal wind. During Northern Hemisphere summer and fall, the temporal variability of the semidiurnal tide at Esrange is found to be well correlated with the amplitude of planetary wavenumber 1 in the stratosphere in high southern latitudes (i.e. in the opposite hemisphere). The correlations indicate that a significant part of the tidal variation at Esrange is due to dynamical interactions in the Southern Hemisphere. A corresponding robust correlation pattern for the Esrange tides is not apparent at other times of the multiple years analyzed. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Univ Bath, Dept Elect & Elect Engn, Bath BA2 7AV, Avon, England. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Smith, AK (reprint author), Natl Ctr Atmospher Res, Div Atmospher Chem, POB 3000, Boulder, CO 80307 USA. EM aksmith@ucar.edu RI Marsh, Daniel/A-8406-2008; Mlynczak, Martin/K-3396-2012 OI Marsh, Daniel/0000-0001-6699-494X; NR 18 TC 24 Z9 24 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 13 PY 2007 VL 34 IS 7 AR L07809 DI 10.1029/2006GL028929 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 157NH UT WOS:000245726400005 ER PT J AU Williams, MB Aydin, M Tatum, C Saltzman, ES AF Williams, Margaret B. Aydin, Murat Tatum, Cheryl Saltzman, Eric S. TI A 2000 year atmospheric history of methyl chloride from a South Pole ice core: Evidence for climate-controlled variability SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MEDIEVAL WARM PERIOD; LAST MILLENNIUM; NORTH-ATLANTIC; EAST-AFRICA; RECORD; TEMPERATURES; RESOLUTION; MONSOON; AIR; PALEOCLIMATE AB Methyl chloride (CH3Cl) is a naturally occurring ozone-depleting gas with a complex biogeochemical cycle involving tropical vegetation, soils, biomass burning and the oceans. This study presents CH3Cl measurements in air extracted from a 300 m ice core from South Pole, Antarctica, covering the time period from 160 BC to 1860 AD. The data exhibit an increasing trend of 3 ppt ( parts per trillion) over 100 years and higher frequency variations that appear to be climate-related. CH3Cl levels were elevated from 900 - 1300 AD by about 50 ppt relative to the previous 1000 years, coincident with the warm Medieval Climate Anomaly (MCA). CH3Cl levels decreased to a minimum during the Little Ice Age cooling ( 1650 - 1800 AD), before rising again to the modern atmospheric level of 550 ppt. These variations most likely reflect changes in tropical and subtropical conditions, and raise the possibility that a warmer future climate may result in higher tropospheric CH3Cl levels. C1 Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA. RP Williams, MB (reprint author), NASA, Ames Res Ctr, Atmospher Chem & Dynam Branch, MS 245-5, Moffett Field, CA 94035 USA. EM mbwilliams@arc.nasa.gov NR 43 TC 9 Z9 9 U1 2 U2 14 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 13 PY 2007 VL 34 IS 7 AR L07811 DI 10.1029/2006GL029142 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 157NH UT WOS:000245726400006 ER PT J AU Sibert, J Hampton, J Kleiber, P Maunder, M AF Sibert, John Hampton, John Kleiber, Pierre Maunder, Mark TI Fishing for good news - Response SO SCIENCE LA English DT Letter C1 Univ Hawaii, Joint Inst Marine & Atmospher Res, Honolulu, HI 96822 USA. Secretariat Pacific Community, Ocean Fisheries Programme, Noumea 98848, New Caledonia. NOAA, Natl Marine Fisheries Serv, Pacific Isl Fisheries Sci Ctr, Honolulu, HI 96822 USA. Interamer Trop Tuna Comm, La Jolla, CA 92037 USA. RP Sibert, J (reprint author), Univ Hawaii, Joint Inst Marine & Atmospher Res, Honolulu, HI 96822 USA. NR 7 TC 2 Z9 2 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD APR 13 PY 2007 VL 316 IS 5822 BP 201 EP 201 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 156MV UT WOS:000245654500019 ER PT J AU Rubincam, DP Paddack, SJ AF Rubincam, David P. Paddack, Stephen J. TI As tiny worlds turn SO SCIENCE LA English DT Editorial Material ID RADIATION; DYNAMICS; TORQUES C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Rubincam, DP (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM David.P.Rubincam@nasa.gov RI Rubincam, David/D-2918-2012 NR 14 TC 1 Z9 1 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD APR 13 PY 2007 VL 316 IS 5822 BP 211 EP 212 DI 10.1126/science.1141930 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 156MV UT WOS:000245654500031 PM 17431161 ER PT J AU Taylor, PA Margot, JL Vokrouhlicky, D Scheeres, DJ Pravec, P Lowry, SC Fitzsimmons, A Nolan, MC Ostro, SJ Benner, LAM Giorgini, JD Magri, C AF Taylor, Patrick A. Margot, Jean-Luc Vokrouhlicky, David Scheeres, Daniel J. Pravec, Petr Lowry, Stephen C. Fitzsimmons, Alan Nolan, Michael C. Ostro, Steven J. Benner, Lance A. M. Giorgini, Jon D. Magri, Christopher TI Spin rate of asteroid (54509) 2000 PH5 increasing due to the YORP effect SO SCIENCE LA English DT Article AB Radar and optical observations reveal that the continuous increase in the spin rate of near-Earth asteroid (54509) 2000 PH5 can be attributed to the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, a torque due to sunlight. The change in spin rate is in reasonable agreement with theoretical predictions for the YORP acceleration of a body with the radar-determined size, shape, and spin state of 2000 PH5. The detection of asteroid spin-up supports the YORP effect as an explanation for the anomalous distribution of spin rates for asteroids under 10 kilometers in diameter and as a binary formation mechanism. C1 Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Charles Univ Prague, Inst Astron, CR-18000 Prague 8, Czech Republic. Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. Acad Sci Czech Republic, Astron Inst, CZ-25165 Ondrejov, Czech Republic. Queens Univ Belfast, Sch Math & Phys, Belfast BT7 1NN, Antrim, North Ireland. Arecibo Observ, Arecibo, PR 00612 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Maine, Farmington, ME USA. RP Taylor, PA (reprint author), Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. EM ptaylor@astro.cornell.edu; jlm@astro.cornell.edu RI Margot, Jean-Luc/A-6154-2012; Nolan, Michael/H-4980-2012; Pravec, Petr/G-9037-2014 OI Margot, Jean-Luc/0000-0001-9798-1797; Nolan, Michael/0000-0001-8316-0680; NR 22 TC 89 Z9 90 U1 0 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD APR 13 PY 2007 VL 316 IS 5822 BP 274 EP 277 DI 10.1126/science.1139038 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 156MV UT WOS:000245654500050 PM 17347415 ER PT J AU Lorenz, RD Wood, CA Lunine, JI Wall, SD Lopes, RM Mitchell, KL Paganelli, F Anderson, YZ Wye, L Tsai, C Zebker, H Stofan, ER AF Lorenz, R. D. Wood, C. A. Lunine, J. I. Wall, S. D. Lopes, R. M. Mitchell, K. L. Paganelli, F. Anderson, Y. Z. Wye, L. Tsai, C. Zebker, H. Stofan, E. R. TI Titan's young surface: Initial impact crater survey by Cassini RADAR and model comparison SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ORIGIN AB Cassini's Radar instrument has mapped over 10% of Titan's surface through the T18 flyby in August 2006 and has detected remarkably few impact craters. Three impact craters have been conclusively identified and named, and a handful of unconfirmed candidate impact structures are documented. These results indicate that the overall crater density is a factor of similar to 5 higher than Earth, and has a size-distribution slope very similar to Earth's indicating rapid obliteration of smaller structures by erosion and burial. The paucity of small craters was expected from atmospheric shielding considerations, but the rarity of medium (20-100 km diameter) craters - some 30-300 times less abundant than on nearby Saturnian satellites - implies rapid resurfacing. Erosion and burial appear to be the dominant means of crater obliteration, with viscous relaxation playing a lesser role. Models of the 20-100 km impact crater production rate suggest an overall crater retention age of 100 Myr-1 Gyr, the same as the corresponding age for the Earth. C1 Johns Hopkins Univ, Appl Phys Lab, Dept Space, Laurel, MD 20723 USA. Wheeling Jesuit Coll, Ctr Educ Technol, Wheeling, WV 26003 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Stanford Univ, Dept Elect Engn, Stanford, CA 94305 USA. Stanford Univ, Dept Geophys, Stanford, CA 94305 USA. Proxemy Res, Bowie, MD 20715 USA. RP Lorenz, RD (reprint author), Johns Hopkins Univ, Appl Phys Lab, Dept Space, Johns Hopkins Rd, Laurel, MD 20723 USA. EM ralph.lorenz@jhuapl.edu RI Lorenz, Ralph/B-8759-2016; Lopes, Rosaly/D-1608-2016 OI Lorenz, Ralph/0000-0001-8528-4644; Lopes, Rosaly/0000-0002-7928-3167 NR 14 TC 49 Z9 49 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 12 PY 2007 VL 34 IS 7 AR L07204 DI 10.1029/2006GL028971 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 157NG UT WOS:000245726300002 ER PT J AU Brohede, SM Haley, CS McLinden, CA Sioris, CE Murtagh, DP Petelina, SV Llewellyn, EJ Bazureau, A Goutail, F Randall, CE Lumpe, JD Taha, G Thomasson, LW Gordley, LL AF Brohede, Samuel M. Haley, Craig S. McLinden, Chris A. Sioris, Christopher E. Murtagh, Donal P. Petelina, Svetlana V. Llewellyn, Edward J. Bazureau, Ariane Goutail, Florence Randall, Cora E. Lumpe, Jerry D. Taha, Ghassan Thomasson, Larry W. Gordley, Larry L. TI Validation of Odin/OSIRIS stratospheric NO2 profiles SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID HALOGEN OCCULTATION EXPERIMENT; SAGE-II; AEROSOL CLIMATOLOGY; CLAES MEASUREMENTS; SOLAR-OCCULTATION; OZONE; INSTRUMENT; SATELLITE; ALGORITHM; PLATFORM AB This paper presents the validation study of stratospheric NO2 profiles retrieved from Odin/OSIRIS measurements of limb-scattered sunlight (version 2.4). The Optical Spectrograph and Infrared Imager System (OSIRIS) NO2 data set is compared to coincident solar occultation measurements by the Halogen Occultation Experiment (HALOE), Stratospheric Aerosol and Gas Experiment (SAGE) II, SAGE III, and Polar Ozone and Aerosol Measurement (POAM) III during the 2002-2004 period. Comparisons with seven Systeme d'Analyse par Observation Zenithal (SAOZ) balloon measurements are also presented. All comparisons show good agreement, with differences, both random and systematic, of less than 20% between 25 km and 35 km. Inconsistencies with SAGE III below 25 km are found to be caused primarily by diurnal effects from varying NO2 concentrations along the SAGE III line-of-sight. On the basis of the differences, the OSIRIS random uncertainty is estimated to be 16% between 15 km and 25 km, 6% between 25 km and 35 km, and 9% between 35 km and 40 km. The estimated systematic uncertainty is about 22% between 15 and 25 km, 11-21% between 25 km and 35 km, and 11-31% between 35 km and 40 km. The uncertainties for AM (sunrise) profiles are generally largest and systematic deviations are found to be larger at equatorial latitudes. The results of this validation study show that the OSIRIS NO2 profiles are well behaved, with reasonable uncertainty estimates between 15 km and 40 km. This unique NO2 data set, with more than hemispheric coverage and high vertical resolution will be of particular interest for studies of nitrogen chemistry in the middle atmosphere, which is closely linked to ozone depletion. C1 Chalmers, Dept Radio & Space Sci, SE-41296 Gothenburg, Sweden. York Univ, Ctr Res Earth & Space Sci, N York, ON M3J 1P3, Canada. Environm Canada, Toronto, ON M3H 5T4, Canada. Univ Saskatchewan, Dept Phys & Engn Phys, Saskatoon, SK S7N 5E2, Canada. CNRS, Serv Aeron, F-91371 Verrieres Le Buisson, France. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Univ Colorado, Dept Atmospher & Ocean Sci, Boulder, CO 80309 USA. Computat Phys Inc, Springfield, VA USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NASA, Langley Res Ctr, Sci Directorate, Hampton, VA 23681 USA. GATS Inc, Newport News, VA 23606 USA. RP Brohede, SM (reprint author), Chalmers, Dept Radio & Space Sci, SE-41296 Gothenburg, Sweden. EM samuel.brohede@chalmers.se; cshaley@yorku.ca; chris.mclinden@ec.gc.ca; csioris@cfa.harvard.edu; donal.murtagh@chalmers.se; svetlana@osirus.usask.ca; edward.llewellyn@usask.ca; ariane.bazureau@aerov.jussieu.fr; florence.goutail@aerov.jussieu.fr; cora.randall@lasp.colorado.edu; lumpe@cpi.com; ghassan_taha@ssaihq.com; l.w.thomasson@nasa.gov; larry@gats-inc.com RI McLinden, Chris/A-7710-2010; The Odin satellite, aeronomy mission/F-1671-2011; Murtagh, Donal/F-8694-2011; Randall, Cora/L-8760-2014 OI McLinden, Chris/0000-0001-5054-1380; Murtagh, Donal/0000-0003-1539-3559; Randall, Cora/0000-0002-4313-4397 NR 41 TC 18 Z9 19 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 12 PY 2007 VL 112 IS D7 AR D07310 DI 10.1029/2006JD007586 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 157NS UT WOS:000245727500003 ER PT J AU Trauger, JT Traub, WA AF Trauger, John T. Traub, Wesley A. TI A laboratory demonstration of the capability to image an Earth-like extrasolar planet SO NATURE LA English DT Article ID TERRESTRIAL PLANETS; CORONAGRAPHS; MASK; MISSION; PUPILS; SPACE AB The detection and characterization of an Earth-like planet orbiting a nearby star requires a telescope with an extraordinarily large contrast at small angular separations. At visible wavelengths, an Earth-like planet would be 1 x 10(-10) times fainter than the star at angular separations of typically 0.1 arcsecond or less(1,2). There are several proposed space telescope systems that could, in principle, achieve this(3-6). Here we report a laboratory experiment that reaches these limits. We have suppressed the diffracted and scattered light near a star- like source to a level of 6 x 10(-10) times the peak intensity in individual coronagraph images. In a series of such images, together with simple image processing, we have effectively reduced this to a residual noise level of about 0.1 x 10(-10). This demonstrates that a coronagraphic telescope in space could detect and spectroscopically characterize nearby exoplanetary systems, with the sensitivity to image an ` Earth- twin' orbiting a nearby star. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Trauger, JT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM john.trauger@jpl.nasa.gov NR 23 TC 163 Z9 163 U1 1 U2 3 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 12 PY 2007 VL 446 IS 7137 BP 771 EP 773 DI 10.1038/nature05729 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 156CX UT WOS:000245626800034 PM 17429394 ER PT J AU Ciotti, L Giampieri, G AF Ciotti, Luca Giampieri, Giacomo TI Exact density-potential pairs from the holomorphic Coulomb field SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE stellar dynamics; celestial mechanics; galaxies : kinematics and dynamics ID CLUSTER ELLIPTIC GALAXIES; TRIAXIAL DARK HALOS; ROTATING BLACK-HOLE; EXTRA-PLANAR GAS; COLLISIONLESS EVAPORATION; STELLAR-SYSTEMS; X-RAY; MODELS; MASS; DYNAMICS AB We show how the complex-shift method developed by Appell to study the gravitational field of a point mass (and used in electrodynamics by, among others, Newman, Carter, Lynden-Bell, and Kaiser to determine some remarkable properties of the electromagnetic field of rotating charged configurations) can be extended to obtain new and explicit density-potential pairs for self-gravitating systems departing significantly from spherical symmetry. The rotational properties of two axisymmetric baroclinic gaseous configurations derived with the proposed method are illustrated. C1 Univ Bologna, Dept Astron, I-40127 Bologna, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ciotti, L (reprint author), Univ Bologna, Dept Astron, Via Ranzani 1, I-40127 Bologna, Italy. EM luca.ciotti@unibo.it NR 58 TC 10 Z9 10 U1 0 U2 0 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 11 PY 2007 VL 376 IS 3 BP 1162 EP 1168 DI 10.1111/j.1365-2966.2007.11497.x PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 155YN UT WOS:000245614800019 ER PT J AU Riess, AG Strolger, LG Casertano, S Ferguson, HC Mobasher, B Gold, B Challis, PJ Filippenko, AV Jha, S Li, WD Tonry, J Foley, R Kirshner, RP Dickinson, M MacDonald, E Eisenstein, D Livio, M Younger, J Xu, C Dahlen, T Stern, D AF Riess, Adam G. Strolger, Louis-Gregory Casertano, Stefano Ferguson, Henry C. Mobasher, Bahram Gold, Ben Challis, Peter J. Filippenko, Alexei V. Jha, Saurabh Li, Weidong Tonry, John Foley, Ryan Kirshner, Robert P. Dickinson, Mark MacDonald, Emily Eisenstein, Daniel Livio, Mario Younger, Josh Xu, Chun Dahlen, Tomas Stern, Daniel TI New hubble space telescope discoveries of type Ia supernovae at z >= 1: Narrowing constraints on the early behavior of dark energy SO ASTROPHYSICAL JOURNAL LA English DT Review DE cosmology : observations; distance scale; galaxies : distances and redshifts; supernovae : general ID HIGH-REDSHIFT SUPERNOVAE; ANISOTROPY-PROBE OBSERVATIONS; DIGITAL SKY SURVEY; COSMOLOGICAL CONSTANT; ACCELERATING UNIVERSE; INTERGALACTIC DUST; OPTICAL-SPECTRA; ADVANCED CAMERA; POWER-SPECTRUM; LEGACY SURVEY AB We have discovered 21 new Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST) and have used them to trace the history of cosmic expansion over the last 10 billion yr. These objects, which include 13 spectroscopically confirmed SNe Ia at z >= 1, were discovered during 14 epochs of reimaging of the GOODS fields North and South over 2 yr with the Advanced Camera for Surveys on HST. Together with a recalibration of our previous HST-discovered SNe Ia, the full sample of 23 SNe Ia at z >= 1 provides the highest redshift sample known. Combining these data with previous SN Ia data sets, we measured H (z) at discrete, uncorrelated epochs, reducing the uncertainty of H (z > 1) from 50% to under 20%, strengthening the evidence for a cosmic jerk - the transition from deceleration in the past to acceleration in the present. The unique leverage of the HST high-redshift SNe Ia provides the first meaningful constraint on the dark energy equation-of-state parameter at z >= 1. The result remains consistent with a cosmological constant [w (z) d - 1] and rules out rapidly evolving dark energy (dw/dz > 1). The defining property of dark energy, its negative pressure, appears to be present at z > 1, in the epoch preceding acceleration, with similar to 98% confidence in our primary fit. Moreover, the z > 1 sample-averaged spectral energy distribution is consistent with that of the typical SN Ia over the last 10 Gyr, indicating that any spectral evolution of the properties of SNe Ia with redshift is still below our detection threshold. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Western Kentucky Univ, Dept Phys & Astron, Bowling Green, KY 42101 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Hawaii, Astron Inst, Honolulu, HI 96822 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Univ Arizona, Steward Observ, Tucson, AZ USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Riess, AG (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NR 104 TC 984 Z9 991 U1 4 U2 30 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2007 VL 659 IS 1 BP 98 EP 121 DI 10.1086/510378 PN 1 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158EF UT WOS:000245773300007 ER PT J AU Crenshaw, DM Kraemer, SB AF Crenshaw, D. M. Kraemer, S. B. TI Mass outflow from the nucleus of the Seyfert 1 galaxy NGC 4151 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual ( NGC 4151); galaxies : Seyfert ID ACTIVE GALACTIC NUCLEI; NARROW-LINE REGION; SPECTROGRAPH ECHELLE OBSERVATIONS; HUBBLE-SPACE-TELESCOPE; X-RAY OBSERVATIONS; PHYSICAL CONDITIONS; NGC 4151; UV ABSORBERS; SIMULTANEOUS ULTRAVIOLET; SPECTROSCOPY AB We present an analysis of UV and optical spectra of NGC 4151 obtained at high spectral and angular resolutions with the Hubble Space Telescope Space Telescope Imaging Spectrograph (HST STIS). We identify a kinematic component of the emission lines that has a width of 1170 km s(-1) (FWHM), intermediate between those from the broad and narrow (emission) line regions (BLRs and NLRs). We present evidence that these emission lines arise from the same gas responsible for most of the high-column UV and X-ray absorption (component "D+E") that we see in outflow at a distance of similar to 0.1 pc from the central nucleus. The gas in this intermediate-line region (ILR) shields the NLR and has a global covering factor of similar to 0.4, based on the observed C IV fluxes, indicating mass outflow over a large solid angle centered on the accretion disk's axis. A large transverse velocity (v(T) greater than or similar to 2100 km s(-1)) compared to the radial velocity centroid (v(r) = -490 km s(-1)) indicates that the kinematics is dominated by rotation at this distance, but has a significant outflow component. The mass outflow rate at 0.1 pc is similar to 0.16 M-circle dot yr(-1), which is about 10 times the accretion rate. Based on physical conditions in the gas and dynamical considerations, models that invoke magneto-centrifugal acceleration (e. g., in an accretion disk wind) are favored over those that rely on radiation driving or thermal expansion as the principal driving mechanism for the mass outflow. C1 Georgia State Univ, Dept Phys & Astron, Astron Off, Atlanta, GA 30303 USA. Catholic Univ Amer, Dept Phys, Inst Astrophys & Computat Sci, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Explorat Universe Div, Greenbelt, MD 20771 USA. RP Crenshaw, DM (reprint author), Georgia State Univ, Dept Phys & Astron, Astron Off, Atlanta, GA 30303 USA. EM crenshaw@chara.gsu.edu; kraemer@yancey.gsfc.nasa.gov NR 36 TC 54 Z9 54 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2007 VL 659 IS 1 BP 250 EP 256 DI 10.1086/511970 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158EF UT WOS:000245773300019 ER PT J AU Lahuis, F Spoon, HWW Tielens, AGGM Doty, SD Armus, L Charmandaris, V Houck, JR Stauber, P van Dishoeck, EF AF Lahuis, F. Spoon, H. W. W. Tielens, A. G. G. M. Doty, S. D. Armus, L. Charmandaris, V. Houck, J. R. Staeuber, P. van Dishoeck, E. F. TI Infrared molecular starburst fingerprints in deeply obscured (ultra) luminous infrared galaxy nuclei SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : ISM; galaxies : nuclei; infrared : ISM; ISM : evolution; ISM : molecules ID SPITZER-SPACE-TELESCOPE; YOUNG STELLAR OBJECTS; SPECTROGRAPH IRS; INTERSTELLAR EXTINCTION; OPTICAL SPECTROSCOPY; CHEMICAL EVOLUTION; GAS; SAMPLE; CHEMISTRY; ENVELOPES AB High-resolution spectra of the Spitzer Space Telescope show vibration-rotation absorption bands of gaseous C2H2, HCN, and CO2 molecules toward a sample of deeply obscured ( U) LIRG nuclei. The observed bands reveal the presence of dense (n greater than or similar to 10(7) cm(-3)), warm (Tex 200-700 K) molecular gas with high column densities of these molecules ranging from a few 1015 to 1017 cm(-2). Abundances relative to H-2, inferred from the silicate optical depth, range from similar to 10(-7) to 10(-6) and show no correlation with temperature. Theoretical studies show that the high abundances of both C2H2 and HCN exclude an X-ray dominated region (XDR) associated with the toroid surrounding an AGN as the origin of this dense warm molecular gas. Galactic massive protostars in the so-called hot-core phase have similar physical characteristics with comparable high abundances of C2H2, HCN, and CO2 in the hot phase. However, the abundances of C2H2 and HCN and the C2H2/CO2 and HCN/CO2 ratios are much higher toward the (U) LIRGs in the cooler ( Tex P 400 K) phase. We suggest that the warm dense molecular gas revealed by the mid-IR absorption lines is associated with a phase of deeply embedded star formation, where the extreme pressures and densities of the nuclear starburst environment have inhibited the expansion of H II regions and the global disruption of the star-forming molecular cloud cores and have "trapped'' the star formation process in an "extended'' hot-core phase. C1 Leiden Observ, NL-2300 RA Leiden, Netherlands. Univ Groningen, SRON Netherlands Inst Space Res, NL-9700 AV Groningen, Netherlands. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Denison Univ, Dept Phys & Astron, Granville, OH 43023 USA. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. Univ Crete, Dept Phys, GR-71003 Iraklion, Greece. Univ Crete, Dept Phys, GR-71110 Iraklion, Greece. Fdn Res & Technol Hellas, IESL, GR-71110 Iraklion, Greece. ETH Zentrum, Inst Astron, CH-8092 Zurich, Switzerland. RP Lahuis, F (reprint author), Leiden Observ, POB 9513, NL-2300 RA Leiden, Netherlands. EM f.lahuis@sron.rug.nl RI Charmandaris, Vassilis/A-7196-2008 OI Charmandaris, Vassilis/0000-0002-2688-1956 NR 54 TC 44 Z9 44 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2007 VL 659 IS 1 BP 296 EP 304 DI 10.1086/512050 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158EF UT WOS:000245773300024 ER PT J AU Turner, NJ Sano, T Dziourkevitch, N AF Turner, N. J. Sano, T. Dziourkevitch, N. TI Turbulent mixing and the dead zone in protostellar disks SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; instabilities; MHD; solar system : formation; stars : formation ID RADIATION MAGNETOHYDRODYNAMICS CODE; DENSE INTERSTELLAR CLOUDS; WEAKLY MAGNETIZED DISKS; 2 SPACE DIMENSIONS; T-TAURI DISKS; MAGNETOROTATIONAL INSTABILITY; PROTOPLANETARY DISKS; IONIZATION FRACTION; ACCRETION DISKS; NONLINEAR EVOLUTION AB We investigate the conditions for the presence of a magnetically inactive dead zone in protostellar disks using three-dimensional shearing-box MHD calculations, including vertical stratification, ohmic resistivity, and time-dependent ionization chemistry. Activity driven by the magneto-rotational instability fills the whole thickness of the disk at 5 AU, provided cosmic-ray ionization is present, small grains are absent, and the gas-phase metal abundance is sufficiently high. At 1 AU, the larger column density of 1700 g cm(-2) means the midplane is shielded from ionizing particles and remains magneto-rotationally stable, even under the most favorable conditions considered. Nevertheless, the dead zone is effectively eliminated. Turbulence mixes free charges into the interior as they recombine, leading to a slight coupling of the midplane gas to the magnetic fields. Weak, large-scale radial fields diffuse to the midplane, where they are sheared out to produce stronger azimuthal fields. On average, the resulting midplane accretion stresses are just a few times less than in the surface layers. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91109 USA. Osaka Univ, Inst Laser Engn, Suita, Osaka 5650871, Japan. Max Planck Inst Astron, D-69117 Heidelberg, Germany. RP Turner, NJ (reprint author), CALTECH, Jet Propuls Lab, Pasadena, CA 91109 USA. EM neal.turner@jpl.nasa.gov; sano@ile.osaka-u.ac.jp; natalia@mpia-hd.mpg.de RI Sano, Takayoshi/E-7860-2010 NR 46 TC 101 Z9 102 U1 0 U2 7 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2007 VL 659 IS 1 BP 729 EP 737 DI 10.1086/512007 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158EF UT WOS:000245773300059 ER PT J AU Leamon, RJ McIntosh, SW AF Leamon, R. J. McIntosh, S. W. TI Empirical solar wind forecasting from the chromosphere SO ASTROPHYSICAL JOURNAL LA English DT Article DE solar-terrestrial relations; solar wind; Sun : atmospheric motions; Sun : chromosphere ID EQUATORIAL CORONAL HOLE; MAGNETIC-FIELDS; ULYSSES; SUN; OSCILLATIONS; HELIOSPHERE; EXPLORER; SPEED AB Recently, we correlated the inferred structure of the solar chromospheric plasma topography with solar wind velocity and composition data measured at 1 AU. We now offer a physical justification of these relationships and present initial results of an empirical prediction model based on them. While still limited by the fundamentally complex physics behind the origins of the solar wind and how its structure develops in the magnetic photosphere and expands into the heliosphere, our model provides a near-continuous range of solar wind speeds and composition quantities that are simply estimated from the inferred structure of the chromosphere. We suggest that the derived quantities may provide input to other, more sophisticated, prediction tools or models such as those that study coronal mass ejection (CME) propagation and solar energetic particle (SEP) generation. C1 ADNET Syst Inc, NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. SW Res Inst, Dept Space Studies, Boulder, CO 80302 USA. RP Leamon, RJ (reprint author), ADNET Syst Inc, NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM leamon@grace.nascom.nasa.gov; mcintosh@boulder.swri.edu NR 25 TC 9 Z9 9 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2007 VL 659 IS 1 BP 738 EP 742 DI 10.1086/511777 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158EF UT WOS:000245773300060 ER PT J AU Raymond, JC Holman, G Ciaravella, A Panasyuk, A Ko, YK Kohl, J AF Raymond, John C. Holman, Gordon Ciaravella, A. Panasyuk, A. Ko, Y.-K. Kohl, J. TI Transition region emission and energy input to thermal plasma during the impulsive phase of solar flares SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : flares; Sun : UV radiation; Sun : X-rays, gamma rays ID ULTRAVIOLET CORONAGRAPH SPECTROMETER; X-RAY-SPECTRA; CHROMOSPHERIC EVAPORATION; SUN; TEMPERATURES; DENSITY; BALANCE; MODELS; RHESSI; IONS AB The energy released in a solar flare is partitioned between thermal and nonthermal particle energy and lost to thermal conduction and radiation over a broad range of wavelengths. It is difficult to determine the conductive losses and the energy radiated at transition region temperatures during the impulsive phases of flares. We use UVCS measurements of O vi photons produced by five flares and subsequently scattered by O vi ions in the corona to determine the 5.0 <= log T <= 6.0 transition region luminosities. We compare them with the rates of increase of thermal energy and the conductive losses deduced from RHESSI and GOES X-ray data using areas from RHESSI images to estimate the loop volumes, cross-sectional areas, and scale lengths. The transition region luminosities during the impulsive phase exceed the X-ray luminosities for the first few minutes, but they are smaller than the rates of increase of thermal energy unless the filling factor of the X-ray-emitting gas is similar to 0.01. The estimated conductive losses from the hot gas are too large to be balanced by radiative losses or heating of evaporated plasma, and we conclude that the area of the flare magnetic flux tubes is much smaller than the effective area measured by RHESSI during this phase of the flares. For the 2002 July 23 flare, the energy deposited by nonthermal particles exceeds the energy radiated in X-rays, the energy radiated at transition region temperatures, and the rate of increase of the thermal energy. C1 Harvard Univ, Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. INAF Osserv Astron Palermo, I-90134 Palermo, Italy. RP Raymond, JC (reprint author), Harvard Univ, Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RI Holman, Gordon/C-9548-2012 NR 41 TC 19 Z9 19 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2007 VL 659 IS 1 BP 750 EP 757 DI 10.1086/512604 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158EF UT WOS:000245773300062 ER PT J AU Ricca, A Bakes, ELO Bauschlicher, CW AF Ricca, Alessandra Bakes, E. L. O. Bauschlicher, Charles W., Jr. TI The energetics for hydrogen addition to naphthalene cations SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; ISM : molecules; methods : numerical; molecular processes ID POLYCYCLIC AROMATIC-HYDROCARBONS; SIDE-GROUP ADDITION; COSMIC ICE ANALOGS; PHOTOCHEMICAL EVOLUTION; FACILE GENERATION; SPECTROSCOPY; IRRADIATION; MOLECULES; CORONENE; SPECTRA AB Energetics of H-addition reactions to the naphthalene cation are determined using computational chemistry techniques. While most of the reactions have little to no barrier, the shape of the potential energy surfaces favors the formation of the product with the added hydrogen atoms being on adjacent carbons. Thus, while many products will be formed, one expects that the product in which all the hydrogen atoms are added to the same or adjacent rings will be favored over a random distribution of added hydrogen atoms. This has implications on the species that will be formed when polycyclic aromatic hydrocarbons (PAHs) are photolyzed in ices in the interstellar medium ( ISM). Barrierless reactions are consistent with the view that PAHs with extra hydrogens contribute to the 3.4 mu m band. C1 SETI Inst, Mountain View, CA 94043 USA. NASA Ames Res Ctr, Space Technol Div, Moffett Field, CA 94035 USA. RP Ricca, A (reprint author), SETI Inst, 514 N Whisman Rd, Mountain View, CA 94043 USA. EM aricca@mail.arc.nasa.gov NR 22 TC 13 Z9 13 U1 1 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2007 VL 659 IS 1 BP 858 EP 861 DI 10.1086/512037 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158EF UT WOS:000245773300071 ER PT J AU Brosius, JW Holman, GD AF Brosius, Jeffrey W. Holman, Gordon D. TI Chromospheric evaporation in a remote solar flare-like transient observed at high time resolution with SOHO's CDS and RHESSI SO ASTROPHYSICAL JOURNAL LA English DT Article DE sun : activity; sun : corona; sun : flares; sun : UV radiation; sun : X-rays, gamma rays ID CORONAL DIAGNOSTIC SPECTROMETER; LOOP RADIATIVE HYDRODYNAMICS; NONTHERMAL ELECTRONS; EXTREME-ULTRAVIOLET; EMISSION; PHASE; DYNAMICS; ABOARD; MODELS; ENERGY AB We present EUV light curves and Doppler velocity measurements for a small, remote flarelike transient observed at high time resolution (9.8 s) with SOHO's CDS during a GOES M1.6 solar flare. The EUV observations include a brief precursor and an impulsive peak followed by a more gradual rise and decline of emission. Hard X-ray light curves obtained with RHESSI reveal a small burst just before the EUV impulsive rise, and another burst at the time of the more gradual EUV peak. RHESSI images show no emission at the location of the EUV transient due to limitations in dynamic range. During the impulsive phase we measure simultaneous, cospatial downward velocities similar to 30 km s(-1) in the chromospheric line of He I at 584.3 angstrom and the transition region line of O v at 629.7 angstrom, and upward velocities similar to 20 km s(-1) in the coronal line of Si XII at 520.7 angstrom. Fe XIX emission at 592.2 angstrom emerged during the impulsive phase and revealed upward velocities approaching 150 km s(-1). These observations demonstrate that flarelike explosive chromospheric evaporation occurred at a location remote from the primary region of particle acceleration, apparently driven by electron beams from the primary acceleration region. C1 Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. RP Brosius, JW (reprint author), Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. EM brosius@helio.gsfc.nasa.gov; Gordon.D.Holman@nasa.gov RI Holman, Gordon/C-9548-2012 NR 30 TC 28 Z9 29 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2007 VL 659 IS 1 BP L73 EP L76 DI 10.1086/516629 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158EM UT WOS:000245774100019 ER PT J AU Ofek, EO Cameron, PB Kasliwal, MM Gal-Yam, A Rau, A Kulkarni, SR Frail, DA Chandra, P Cenko, SB Soderberg, AM Immler, S AF Ofek, E. O. Cameron, P. B. Kasliwal, M. M. Gal-Yam, A. Rau, A. Kulkarni, S. R. Frail, D. A. Chandra, P. Cenko, S. B. Soderberg, A. M. Immler, S. TI SN 2006gy: An extremely luminous supernova in the galaxy NGC 1260 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 1260); supernovae : general; supernovae : individual (SN 2006gy) ID IA SUPERNOVA; PROGENITOR; STAR; SPECTROSCOPY; ULTRAVIOLET; RESOLUTION; EVOLUTION; ENVELOPE; SYSTEM; PUZZLE AB With an extinction-corrected V-band peak absolute magnitude of about -22, supernova SN 2006gy is probably the brightest SN ever observed. We report on multiwavelength observations of this SN and its environment. Our spectroscopy shows an Ha emission line as well as absorption features that may be identified as Si II lines at low expansion velocity. The slow brightening, the peak luminosity, and the Ha emission line resemble those observed in hybrid Type IIn/Ia SNe ( also known as Type IIa) and may suggest that SN 2006gy is related to the Type IIa SNe class. The host galaxy, NGC 1260, is dominated by an old stellar population with solar metallicity. However, our high-resolution adaptive optics images reveal a dust lane in this galaxy, and there appears to be an H II region in the vicinity of the SN. The extraordinarily large peak luminosity, similar to 3 x 10(44) ergs s(-1), demands a dense circumstellar medium, regardless of the mass of the progenitor star. The inferred mass-loss rate of the progenitor is -0.1 M circle dot yr(-1) over a period of similar to 10 yr prior to explosion. Such an high mass-loss rate may be the result of a binary star common envelope ejection. The total radiated energy in the first 2 months is about 1.1 x 10(51) ergs, which is only a factor of 2 less than that available from a super-Chandrasekhar Type Ia explosion. Therefore, given the presence of a star-forming region in the vicinity of the SN and the high-energy requirements, a plausible scenario is that SN 2006gy is related to the death of a massive star. C1 CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. Natl Radio Astron Observ, Charlottesville, VA 22903 USA. Univ Virginia, Charlottesville, VA 22904 USA. NASA, Goddard Space Flight Ctr, CRESST, Greenbelt, MD 20771 USA. RP Ofek, EO (reprint author), CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. NR 43 TC 150 Z9 150 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2007 VL 659 IS 1 BP L13 EP L16 DI 10.1086/516749 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158EM UT WOS:000245774100004 ER PT J AU Zhou, S Kuang, W Jiang, W Gary, P Palencia, J Gardner, G AF Zhou, S. Kuang, W. Jiang, W. Gary, P. Palencia, J. Gardner, G. TI High-speed network and Grid computing for high-end computation: application in geodynamics ensemble simulations SO CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE LA English DT Article; Proceedings Paper CT Workshop on Component and Framework Technology in High-Performance and Scientific Computing CY 2005 CL Atlanta, GA DE high-speed network; Grid computing; framework; geodynamo; data assimilation ID MODELS AB High-speed network and Grid computing have been actively investigated, and their capabilities are being demonstrated. However, their application to high-end scientific computing and modeling is still to be explored. In this paper we discuss the related issues and present our prototype work on applying XCAT3 framework technology to geomagnetic data assimilation development with distributed computers, connected through an up to 10 Gigabit Ethernet network. Copyright (c) 2006 John Wiley & Sons, Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Northrop Grumman Corp, Chantilly, VA 20151 USA. Univ Maryland Baltimore Cty, JCET, Baltimore 21250, MD USA. Pittsburgh Supercomp Ctr, Pittsburgh, PA 15213 USA. Earth Resources Technol, Jessup, MD 20794 USA. RP Zhou, S (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM szhou@pop900.gsfc.nasa.gov RI Kuang, Weijia/K-5141-2012 OI Kuang, Weijia/0000-0001-7786-6425 NR 9 TC 1 Z9 1 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 1532-0626 J9 CONCURR COMP-PRACT E JI Concurr. Comput.-Pract. Exp. PD APR 10 PY 2007 VL 19 IS 5 SI SI BP 573 EP 582 DI 10.1002/cpe.1060 PG 10 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 155IY UT WOS:000245572300002 ER PT J AU Zhou, SJ Balaji, V Cruz, C da Silva, A Hill, C Kluzek, E Smithline, S Trayanov, A Yang, WY AF Zhou, Shujia Balaji, V. Cruz, Carlos da Silva, Arlindo Hill, Chris Kluzek, Erik Smithline, Shep Trayanov, Atanas Yang, Weiyu TI Cross-organization interoperability experiments of weather and climate models with the Earth System Modeling Framework SO CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE LA English DT Article; Proceedings Paper CT Workshop on Component and Framework Technology in High-Performance and Scientific Computing CY 2005 CL Atlanta, GA DE framework; weather model; climate model; model coupling; component ID ARCHITECTURE AB Typical weather and climate models need a software tool to couple sub-scale model components. The high-performance computing requirements and a variety of model interfaces make the development of such a coupling tool very challenging. In this paper, we describe the approach of the Earth System Modeling Framework, in particular its component and coupling mechanism, and present the results of three cross-organization model interoperability experiments. Copyright (c) 2006 John Wiley & Sons, Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Princeton Univ, Princeton, NJ 08450 USA. MIT, Cambridge, MA 02139 USA. Natl Ctr Atmospher Res, Boulder, CO 80305 USA. Natl Ctr Environm Predict, Camp Springs, MD 20746 USA. RP Zhou, SJ (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM szhou@pop900.gsfc.nasa.gov RI da Silva, Arlindo/D-6301-2012 OI da Silva, Arlindo/0000-0002-3381-4030 NR 9 TC 1 Z9 1 U1 0 U2 3 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 1532-0626 J9 CONCURR COMP-PRACT E JI Concurr. Comput.-Pract. Exp. PD APR 10 PY 2007 VL 19 IS 5 SI SI BP 583 EP 592 DI 10.1002/cpe.1120 PG 10 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 155IY UT WOS:000245572300003 ER PT J AU Palo, SE Forbes, JM Zhang, X Russell, JM Mlynczak, MG AF Palo, S. E. Forbes, J. M. Zhang, X. Russell, J. M., III Mlynczak, M. G. TI An eastward propagating two-day wave: Evidence for nonlinear planetary wave and tidal coupling in the mesosphere and lower thermosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ASYNOPTIC SATELLITE-OBSERVATIONS; QUASI-2-DAY WAVE; MIDDLE ATMOSPHERE; SAMPLING THEORY; TEMPERATURE; RESOLUTION; SABER; MODEL AB Temperature observations from the SABER instrument on the TIMED spacecraft are used to investigate the structure and evolution of an eastward propagating zonal wavenumber 2 disturbance with a period near two days. This oscillation obtains a maximum amplitude of nearly 10 K in the southern hemisphere mid-latitudes during late January. The timing and location of this planetary wave is coincident with the regular quasi two-day wave intensification that occurs annually in late January. The period, wavenumber and spatial structure of the eastward propagating two-day wave are consistent with a wave that results from a nonlinear interaction between the quasi two-day wave and the migrating diurnal tide. The existence of an eastward propagating wave with a period near two days coincident with the westward propagating two day wave will have an impact on the interpretation of ground based observations. Analysis of the SABER temperature observations are utilized to determine the structure and evolution of both this eastward propagating two-day wave and the classic westward propagating zonal wavenumber 3 quasi two-day wave during January 2005. C1 Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Palo, SE (reprint author), Univ Colorado, Dept Aerosp Engn Sci, Campus Box 429, Boulder, CO 80309 USA. EM scott.palo@colorado.edu RI Mlynczak, Martin/K-3396-2012; OI PALO, SCOTT/0000-0002-4729-4929; FORBES, JEFFREY/0000-0001-6937-0796 NR 18 TC 38 Z9 38 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 10 PY 2007 VL 34 IS 7 AR L07807 DI 10.1029/2006GL027728 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 157ND UT WOS:000245726000001 ER PT J AU Dong, JR Walker, JP Houser, PR Sun, CJ AF Dong, Jiarui Walker, Jeffrey P. Houser, Paul R. Sun, Chaojiao TI Scanning multichannel microwave radiometer snow water equivalent assimilation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NORTHERN GREAT-PLAINS; LAND-SURFACE MODEL; SOIL-MOISTURE; CLIMATE MODEL; COVER; VARIABILITY; METHODOLOGY; UNCERTAINTY; SYSTEM AB Accurate prediction of snowpack status is important for a range of environmental applications, yet model estimates are typically poor and in situ measurement coverage is inadequate. Moreover, remote sensing estimates are spatially and temporally limited due to complicating effects, including distance to open water, presence of wet snow, and presence of thick snow. However, through assimilation of remote sensing estimates into a land surface model, it is possible to capitalize on the strengths of both approaches. In order to achieve this, reliable estimates of the uncertainty in both remotely sensed and model simulated snow water equivalent (SWE) estimates are critical. For practical application, the remotely sensed SWE retrieval error is prescribed with a spatially constant but monthly varying value, with data omitted for (1) locations closer than 200 km to significant open water, (2) times and locations with model-predicted presence of liquid water in the snowpack, and (3) model SWE estimates greater than 100 mm. The model error is estimated using standard error propagation with a calibrated spatially and temporally constant model error contribution. A series of tests have been performed to assess the assimilation algorithm performance. Multiyear model simulations with and without remotely sensed SWE assimilation are presented and evaluated with in situ SWE observations. The SWE estimates from assimilation were found to be superior to both the model simulation and remotely sensed estimates alone, except when model SWE estimates rapidly and erroneously crossed the 100-mm SWE cutoff early in the snow season. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. Univ Melbourne, Dept Civil & Environm Engn, Parkville, Vic 3010, Australia. George Mason Univ, Coll Sci, Climate Dynam Dept, Beltsville, MD 20705 USA. Ctr Res Environm & Water, Beltsville, MD 20705 USA. NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. RP Dong, JR (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Code 614-3, Greenbelt, MD 20771 USA. EM jiarui@hsb.gsfc.nasa.gov RI Sun, Chaojiao/A-9569-2011; Walker, Jeffrey/D-2624-2009 OI Sun, Chaojiao/0000-0002-7030-0485; NR 32 TC 34 Z9 35 U1 3 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 10 PY 2007 VL 112 IS D7 AR D07108 DI 10.1029/2006JD007209 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 157NO UT WOS:000245727100001 ER PT J AU Chen, JY Schopf, JW Bottjer, DJ Zhang, CY Kudryavtsev, AB Tripathi, AB Wang, XQ Yang, YH Gao, X Yang, Y AF Chen, Jun-Yuan Schopf, J. William Bottjer, David J. Zhang, Chen-Yu Kudryavtsev, Anatoliy B. Tripathi, Abhishek B. Wang, Xiu-Qiang Yang, Yong-Hua Gao, Xiang Yang, Ying TI Raman spectra of a lower Cambrian ctenophore embryo from southwestern Shaanxi, China SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE comb jelly; confocal laser scanning microscopy; Meishucun fossil assemblage; Ningqiang fossil fauna ID SOUTHERN SHAANXI; METAZOAN EMBRYOS; IMAGERY; FOSSILS AB The Early Cambrian (approximate to 540 million years old) Meishucun fossil assemblage of Ningqiang County (Shaanxi Province), China, contains the oldest complex skeletonized organisms known in the geological record. We here report the finding in this assemblage of an exquisitely preserved late-stage embryo of a ctenophore ("comb jelly"), its fine structure documented by confocal laser scanning microscopy and shown by Raman spectroscopy to be composed of carbonaceous kerogen permineralized in apatite. In its spheroidal morphology, the presence of eight comb rows and the absence of tentacles, this embryo resembles an adult ctenophore (Maotianoascus octonarius) known from the immediately younger Chengjiang fauna of Yunnan, China. The oldest ctenophore and the only embryonic comb jelly known from the fossil record, this exceptionally well preserved specimen provides important clues about the early evolution of the phylum Ctenophora and of metazoans in general. C1 Nanjing Univ, Nanjing Int Geol & Palaeontol, Nanjing 210093, Peoples R China. Nanjing Univ, Int Evo Dev Biol, Nanjing 210093, Peoples R China. Nanjing Univ, State Key Lab Pharmaceut Biotechnol, Nanjing 210093, Peoples R China. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Ctr Study Evolut & Origin Life, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Inst Mol Biol, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, NASA, Astrobiol Inst, Los Angeles, CA 90095 USA. Univ So Calif, Dept Earth Sci, Los Angeles, CA 90089 USA. RP Chen, JY (reprint author), Nanjing Univ, Nanjing Int Geol & Palaeontol, Nanjing 210093, Peoples R China. EM chenjy@nju.edu.cn NR 25 TC 45 Z9 56 U1 0 U2 10 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD APR 10 PY 2007 VL 104 IS 15 BP 6289 EP 6292 DI 10.1073/pnas.0701246104 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 157RG UT WOS:000245737500036 PM 17404242 ER PT J AU Kumar, A Acrivos, A Khusid, B James, CD Jacqmin, D AF Kumar, Anil Acrivos, Andreas Khusid, Boris James, Conrad D. Jacqmin, David TI Conveyor-belt method for assembling microparticles into large-scale structures using electric fields SO APPLIED PHYSICS LETTERS LA English DT Article ID MANIPULATION; PARTICLES AB The authors propose and experimentally demonstrate a conveyor-belt method appropriate for building large-scale microparticle structures by sequentially energizing electrodes to aggregate the particles into predetermined locations and then to translate them collectively to a work area for final assembly. This approach employs collective phenomena in a negatively polarized suspension exposed to a high-gradient strong ac electric field. (c) 2007 American Institute of Physics. C1 Levich Inst, New York, NY 10031 USA. New Jersey Inst Technol, Newark, NJ 07102 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Kumar, A (reprint author), Levich Inst, 140th St & Convent Ave, New York, NY 10031 USA. EM anil@levdec.engr.ccny.cuny.edu; acrivos@sci.ccny.cuny.edu; khusid@adm.njit.edu; cdjame@sandia.gov; fsdavid@tess.lerc.nasa.gov OI Khusid, Boris/0000-0002-8604-1051 NR 15 TC 0 Z9 0 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 9 PY 2007 VL 90 IS 15 AR 154104 DI 10.1063/1.2721238 PG 3 WC Physics, Applied SC Physics GA 157AJ UT WOS:000245690700122 ER PT J AU Nedoluha, GE Benson, CM Hoppel, KW Alfred, J Bevilacqua, RM Drdla, K AF Nedoluha, Gerald E. Benson, Craig M. Hoppel, Karl W. Alfred, Jerome Bevilacqua, Richard M. Drdla, Katja TI Antarctic dehydration 1998-2003: Polar ozone and aerosol measurement III (POAM) measurements and integrated microphysics and aerosol chemistry on trajectories (IMPACT) results with four meteorological models SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WATER-VAPOR; STRATOSPHERE; VORTEX; TEMPERATURES; WINTER AB [1] We present Polar Ozone and Aerosol Measurement III (POAM) measurements of Antarctic dehydration from 1998 to 2003 and compare these measurements with calculations performed with the Integrated Microphysics and Aerosol Chemistry on Trajectories (IMPACT) microphysical model. Previous work has shown that while dehydration is not very sensitive to reasonable changes of microphysical parameters, it is very sensitive to changes in temperature. We shall therefore compare dehydration as measured by POAM with IMPACT model runs based on four meteorological analyses: United Kingdom Meteorological Office (UKMO), European Centre for Medium-Range Weather Forecasts (ECMWF), National Centers for Environmental Prediction Climate Prediction Center (NCEP-CPC), and NCEP reanalysis. For the years 1998-2000, the agreement between the minimum water vapor found in the POAM measurements and that from all of the model runs is always within 0.5 ppmv. The disagreement between POAM and some of the models is larger in the years 2001-2003, growing as large as similar to 1 ppmv, but the agreement between the minimum POAM water vapor and the water vapor calculated using the NCEP reanalysis is always within 0.2 ppmv. If we infer a temperature bias from the difference between the NCEP reanalysis model runs and the POAM minimum water vapor measurements, we find that this temperature bias is < 0.5 K for each of the 6 years from 1998 to 2003, but it is often larger for the other meteorological analyses. C1 USN, Res Lab, Washington, DC 20375 USA. Computat Phys Inc, Springfield, VA USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Nedoluha, GE (reprint author), USN, Res Lab, 4555 Overlook Ave,Code 7277, Washington, DC 20375 USA. EM nedoluha@nrl.navy.mil NR 29 TC 2 Z9 2 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 7 PY 2007 VL 112 IS D7 AR D07305 DI 10.1029/2006JD007414 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155MC UT WOS:000245580500004 ER PT J AU Whitten, RC Borucki, WJ Tripathi, S AF Whitten, R. C. Borucki, W. J. Tripathi, S. TI Predictions of the electrical conductivity and charging of the aerosols in Titan's nighttime atmosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID POLYCYCLIC AROMATIC-HYDROCARBONS; MAGNETOSPHERE; PROPAGATION; PARTICLES AB [1] The electrical conductivity and electrical charge on Titan's atmosphere are computed for altitudes between 0 and 400 km on the nightside for which the main source of ionization is galactic cosmic rays (GCR). Unlike the dayside, electrical charging of the aerosol particles at night is not only negative but also time-dependent. Hence a time-dependent model must be employed for computations of electron and ion densities as well as aerosol charging over the night hemisphere. After developing a method for computing the time-dependent charge states of the aerosol particles, we found that that at altitudes above about 60 km ( the effusion range) the charging of the aerosols at the antisolar point is quite close to that at steady state; however, at lower altitudes where ( the slow) diffusion of the electrons and ions prevails, the electron density is larger ( and the charging of the aerosol particles is smaller) than at steady state. Because polycyclic aromatic hydrocarbons (PAHs) are expected in Titan's atmosphere and have been observed in the laboratory and found to be electrophillic, we have included the formation of negative ions in the aerosol charging model. Such ions are of major importance at night between about 170 and 360 km where they capture most of the negative charge. As a result they greatly reduce the electron density and thus the electrical conductivity in that altitude range. The charge distributions at 50 km ( diffusion range), 150 km ( effusion range with few negative ions), and 250 km ( effusion range) are presented. C1 SETI Inst, Mountain View, CA 94043 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Indian Inst Technol, Kanpur 208016, Uttar Pradesh, India. RP Whitten, RC (reprint author), SETI Inst, 515 N Whisman Rd, Mountain View, CA 94043 USA. EM rwhitten@pacbell.net RI Tripathi, Sachchida/J-4840-2016 NR 24 TC 11 Z9 11 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 7 PY 2007 VL 112 IS E4 AR E04001 DI 10.1029/2006JE002788 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 155MZ UT WOS:000245582800001 ER PT J AU Beck, BR Becker, JA Beiersdorfer, P Brown, GV Moody, KJ Wilhelmy, JB Porter, FS Kilbourne, CA Kelley, RL AF Beck, B. R. Becker, J. A. Beiersdorfer, P. Brown, G. V. Moody, K. J. Wilhelmy, J. B. Porter, F. S. Kilbourne, C. A. Kelley, R. L. TI Energy splitting of the ground-state doublet in the nucleus Th-229 SO PHYSICAL REVIEW LETTERS LA English DT Article ID EXCITED-STATE; ASTRO-E2; ISOMER; DECAY; SPECTROSCOPY; EMISSION; LEVEL AB The energy splitting of the Th-229 ground-state doublet is measured to be 7.6 +/- 0.5 eV, significantly greater than earlier measurements. Gamma rays produced following the alpha decay of U-233 (105 mu Ci) were counted in the NASA/electron beam ion trap x-ray microcalorimeter spectrometer with an experimental energy resolution of 26 eV (FWHM). A difference technique was applied to the gamma-ray decay of the 71.82 keV level that populates both members of the doublet. A positive correction amounting to 0.6 eV was made for the unobserved interband decay of the 29.19 keV state (29.19 -> 0 keV). C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Beck, BR (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Porter, Frederick/D-3501-2012; Kelley, Richard/K-4474-2012 OI Porter, Frederick/0000-0002-6374-1119; NR 26 TC 123 Z9 123 U1 0 U2 13 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 6 PY 2007 VL 98 IS 14 AR 142501 DI 10.1103/PhysRevLett.98.142501 PG 4 WC Physics, Multidisciplinary SC Physics GA 154MQ UT WOS:000245512100020 PM 17501268 ER PT J AU Plaut, JJ Picardi, G Safaeinili, A Ivanov, AB Milkovich, SM Cicchetti, A Kofman, W Mouginot, J Farrell, WM Phillips, RJ Clifford, SM Frigeri, A Orosei, R Federico, C Williams, IP Gurnett, DA Nielsen, E Hagfors, T Heggy, E Stofan, ER Plettemeier, D Watters, TR Leuschen, CJ Edenhofer, P AF Plaut, Jeffrey J. Picardi, Giovanni Safaeinili, Ali Ivanov, Anton B. Milkovich, Sarah M. Cicchetti, Andrea Kofman, Wlodek Mouginot, Jeremie Farrell, William M. Phillips, Roger J. Clifford, Stephen M. Frigeri, Alessandro Orosei, Roberto Federico, Costanzo Williams, Iwan P. Gurnett, Donald A. Nielsen, Erling Haegfors, Tor Heggy, Essam Stofan, Ellen R. Plettemeier, Dirk Watters, Thomas R. Leuschen, Carlton J. Edenhofer, Peter TI Subsurface radar sounding of the south polar layered deposits of Mars SO SCIENCE LA English DT Article ID CAP; REGION AB The ice-rich south polar layered deposits of Mars were probed with the Mars Advanced Radar for Subsurface and Ionospheric Sounding on the Mars Express orbiter. The radar signals penetrate deep into the deposits (more than 3.7 kilometers). For most of the area, a reflection is detected at a time delay that is consistent with an interface between the deposits and the substrate. The reflected power from this interface indicates minimal attenuation of the signal, suggesting a composition of nearly pure water ice. Maps were generated of the topography of the basal interface and the thickness of the layered deposits. A set of buried depressions is seen within 300 kilometers of the pole. The thickness map shows an asymmetric distribution of the deposits and regions of anomalous thickness. The total volume is estimated to be 1.6 x 10(6) cubic kilometers, which is equivalent to a global water layer approximately 11 meters thick. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Roma La Sapienza, Infocom Dept, I-00184 Rome, Italy. Lab Planetol Grenoble, F-38041 Grenoble, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. Lunar & Planetary Inst, Houston, TX 77058 USA. Univ Perugia, Dipartimento Sci Terra, I-06123 Perugia, Italy. Ist Nazl Astrofis, Ist Fis Spazio Interplanetario, I-00133 Rome, Italy. Queen Mary Univ London, Sch Math Sci, Astron Unit, London E1 4NS, England. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Max Planck Inst Solar Syst Res, D-37191 Katlenburg Lindau, Germany. Proxemy Res, Laytonville, MD 20882 USA. Tech Univ Dresden, Fak Elekrtotech & Informat Tech, D-01062 Dresden, Germany. Smithsonian Inst, Ctr Earth & Planetary Studies, Natl Air & Space Museum, Washington, DC 20560 USA. Univ Kansas, Ctr Remote Sensing Ice Sheets, Lawrence, KS 66045 USA. Ruhr Univ Bochum, Fak Elektrotech & Informat Tech, D-44780 Bochum, Germany. RP Plaut, JJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Kofman, Wlodek/C-4556-2008; Frigeri, Alessandro/F-2151-2010; Heggy, Essam/E-8250-2013; Farrell, William/I-4865-2013; Ivanov, Anton/C-8944-2014; Mouginot, Jeremie/G-7045-2015; OI Frigeri, Alessandro/0000-0002-9140-3977; Heggy, Essam/0000-0001-7476-2735; Ivanov, Anton/0000-0001-8376-8581; CICCHETTI, ANDREA/0000-0002-9588-6531; Williams, Iwan Prys/0000-0002-8069-1344 NR 19 TC 125 Z9 126 U1 2 U2 25 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD APR 6 PY 2007 VL 316 IS 5821 BP 92 EP 95 DI 10.1126/science.1139672 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 153XD UT WOS:000245470500038 PM 17363628 ER PT J AU Kiss, P Janosi, IM Torres, O AF Kiss, P. Janosi, I. M. Torres, O. TI Early calibration problems detected in TOMS Earth-Probe aerosol signal SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID FOREST-FIRE SMOKE; TRANSPORT; INDEX AB TOMS ( version 8) ozone and aerosol data are analyzed in order to extract characteristic temporal patterns on a near global scale. A clear annual cycle of the global average for the ozone is apparent in the measured intervals (Nimbus-7: 1978 - 1993, Earth-Probe: 1996 - 2005), however a similar initial periodicity disappears for the aerosol index in the Earth-Probe records. A detailed spectral analysis revealed significant asymmetries in the Nimbus-7 aerosol signal for the two hemispheres, which is not present in Earth-Probe data. The available record from the Ozone Monitoring Instrument ( one and a half years) shows a return to the seasonal variability seen by Nimbus-7 in both hemispheres. This suggests that calibration difficulties of the Earth-Probe instrument started earlier than mid 2000, when it became apparent from many indications. C1 Eotvos Lorand Univ, Dept Phys Complex Syst, H-1518 Budapest, Hungary. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. RP Kiss, P (reprint author), Eotvos Lorand Univ, Dept Phys Complex Syst, POB 32, H-1518 Budapest, Hungary. EM janosi@lecso.elte.hu; torres@qhearts.gsfc.nasa.gov RI Kiss, Peter/G-5711-2010; Torres, Omar/G-4929-2013 NR 16 TC 20 Z9 20 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 5 PY 2007 VL 34 IS 7 AR L07803 DI 10.1029/2006GL028108 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 155LK UT WOS:000245578700001 ER PT J AU Fenton, LK Geissler, PE Haberle, RM AF Fenton, Lori K. Geissler, Paul E. Haberle, Robert M. TI Global warming and climate forcing by recent albedo changes on Mars SO NATURE LA English DT Article ID THERMAL MAPPER OBSERVATIONS; INTERANNUAL VARIABILITY; POLAR-REGIONS; TES; FEATURES; MODEL AB For hundreds of years, scientists have tracked the changing appearance of Mars, first by hand drawings and later by photographs(1,2). Because of this historical record, many classical albedo patterns have long been known to shift in appearance over time. Decadal variations of the martian surface albedo are generally attributed to removal and deposition of small amounts of relatively bright dust on the surface. Large swaths of the surface ( up to 56 million km(2)) have been observed to darken or brighten by 10 per cent or more(3-5). It is unknown, however, how these albedo changes affect wind circulation, dust transport and the feedback between these processes and the martian climate. Here we present predictions from a Mars general circulation model, indicating that the observed interannual albedo alterations strongly influence the martian environment. Results indicate enhanced wind stress in recently darkened areas and decreased wind stress in brightened areas, producing a positive feedback system in which the albedo changes strengthen the winds that generate the changes. The simulations also predict a net annual global warming of surface air temperatures by similar to 0.65 K, enhancing dust lifting by increasing the likelihood of dust devil generation. The increase in global dust lifting by both wind stress and dust devils may affect the mechanisms that trigger large dust storm initiation, a poorly understood phenomenon, unique to Mars. In addition, predicted increases in summertime air temperatures at high southern latitudes would contribute to the rapid and steady scarp retreat that has been observed in the south polar residual ice for the past four Mars years(6-8). Our results suggest that documented albedo changes affect recent climate change and large-scale weather patterns on Mars, and thus albedo variations are a necessary component of future atmospheric and climate studies. C1 US Geol Survey, Flagstaff, AZ 86001 USA. NASA, Ames Res Ctr, Carl Sagan Ctr, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Fenton, LK (reprint author), US Geol Survey, Flagstaff, AZ 86001 USA. EM fenton@mintz.arc.nasa.gov; pgeissler@usgs.gov NR 25 TC 41 Z9 41 U1 2 U2 7 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 5 PY 2007 VL 446 IS 7136 BP 646 EP 649 DI 10.1038/nature05718 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 153LZ UT WOS:000245438300034 PM 17410170 ER PT J AU Morison, J Wahr, J Kwok, R Peralta-Ferriz, C AF Morison, James Wahr, John Kwok, Ron Peralta-Ferriz, Cecilia TI Recent trends in Arctic Ocean mass distribution revealed by GRACE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SEA-ICE; GRAVITY; TEMPERATURE; FIELDS; MODEL; LAYER; AGE AB Measurements of ocean bottom pressure by the Gravity Recovery and Climate Experiment (GRACE) and new in situ bottom pressure measurements confirm the accuracy and utility of GRACE measurements in the Arctic Ocean. They reveal a declining trend in bottom pressure that corresponds to mass changes due to decreasing upper ocean salinities near the North Pole and in the Makarov Basin. The spatial distribution and magnitude of these trends suggest the Arctic Ocean is reverting from the cyclonic state characterizing the 1990s to the anticyclonic state that was prevalent prior to the 1990s. C1 Univ Washington, Appl Phys Lab, Polar Sci Ctr, Seattle, WA 98105 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Morison, J (reprint author), Univ Washington, Appl Phys Lab, Polar Sci Ctr, 1013 NE 40th St, Seattle, WA 98105 USA. EM morison@apl.washington.edu RI Kwok, Ron/A-9762-2008 OI Kwok, Ron/0000-0003-4051-5896 NR 27 TC 43 Z9 45 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 4 PY 2007 VL 34 IS 7 AR L07602 DI 10.1029/2006GL029016 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 155LI UT WOS:000245578500003 ER PT J AU Nakamura, Y Bowman, RC Akiba, E AF Nakamura, Yumiko Bowman, Robert C., Jr. Akiba, Etsuo TI Variation of hydrogen occupation in LaNi4.78Sn0.22Dx along the P-C isotherms studied by in situ neutron powder diffraction SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE in situ neutron powder diffraction; crystal structure; hydrogen occupation; Rietveld refinement ID INITIAL ACTIVATION PROCESS; X-RAY-DIFFRACTION; CRYSTAL-STRUCTURE; HYDRIDES; LANI5 AB We performed in situ neutron powder diffraction measurements of LaN4.78Sn0.22Dx along the absorption and desorption pressure-composition (P-C) isotherms using 90 degrees banks of a TOF diffractometer. Structure of the hydride phase for various hydrogen contents was analyzed by the Rietveld method. Variation of the hydrogen occupation and the lattice parameters for the hydride phase was investigated. The full hydride LaNi4.78Sn0.22D6.1 has a P6mm structure with four hydrogen sites; 3c sites (O[La2Ni4]), 6e(1) sites (T[La2Ni2]), 6e(2) sites (T[La1Ni3]) and 2b sites (T[Ni-4]) with occupancies of 0.98(2), 0.34(1), 0.168(9) and 0.24(2), respectively. The 3c site was fully occupied regardless of the total hydrogen content. Occupancies of the other three sites changed depending on the hydrogen content, with hysteresis between absorption and desorption in the two-phase region. The hydrogen occupation and the lattice parameters for the hydride phase varied even in the two-phase region during desorption. (c) 2006 Elsevier B.V. All rights reserved. C1 AIST Cent 5, Natl Inst Adv Ind Sci & Technol, Tsukuba, Ibaraki 3058565, Japan. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nakamura, Y (reprint author), AIST Cent 5, Natl Inst Adv Ind Sci & Technol, 1-1-1 Higashi, Tsukuba, Ibaraki 3058565, Japan. EM yumiko.nakamura@aist.go.jp OI Bowman, Robert/0000-0002-2114-1713 NR 17 TC 8 Z9 8 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD APR 4 PY 2007 VL 431 IS 1-2 BP 148 EP 154 DI 10.1016/j.jallcom.2006.05.082 PG 7 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 154HT UT WOS:000245498300029 ER PT J AU Schmidt, AM McGuire, MA Gascoin, F Snyder, GJ DiSalvo, FJ AF Schmidt, Anneliese M. McGuire, Michael A. Gascoin, Franck Snyder, G. Jeffrey DiSalvo, Francis J. TI Synthesis and thermoelectric properties of (CuyMo6Se8)(1-x)(Mo4Ru2Se8)(x) alloys SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE semiconductors; X-ray diffraction; electronic transport ID CHEVREL PHASES; X-RAY; CLUSTERS; INTERCALATION; SUBSTITUTION; SNMO6S8; METAL AB The Chevrel phase solid solutions (CuyMo6Se8)(1-x)(Mo4Ru2Se8)(x), with nominal y = 2, 4 and x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0 have been investigated in efforts to find improved high temperature thermoelectric materials. The samples were characterized by powder X-ray diffraction, and compositions were measured using quantitative electron microprobe analysis. The resistivity and Seebeck coefficient are reported from room temperature up to approximately 1100 K. From these measurements we estimate the thermoelectric figure of merit ZT, and the most promising compound had ZT approximate to 0.37 at 1000 K. (c) 2006 Elsevier B.V. All rights reserved. C1 Cornell Univ, Dept Chem & Biol Chem, Baker Lab, Ithaca, NY 14853 USA. Cornell Univ, Dept Phys, Ithaca, NY 14853 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP DiSalvo, FJ (reprint author), Cornell Univ, Dept Chem & Biol Chem, Baker Lab, Ithaca, NY 14853 USA. EM fjd3@cornell.edu RI Snyder, G. Jeffrey/E-4453-2011; Snyder, G/I-2263-2015; McGuire, Michael/B-5453-2009 OI Snyder, G. Jeffrey/0000-0003-1414-8682; McGuire, Michael/0000-0003-1762-9406 NR 29 TC 6 Z9 6 U1 1 U2 10 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD APR 4 PY 2007 VL 431 IS 1-2 BP 262 EP 268 DI 10.1016/j.jallcom.2006.05.061 PG 7 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 154HT UT WOS:000245498300050 ER PT J AU Singh, HB Salas, L Herlth, D Kolyer, R Czech, E Avery, M Crawford, JH Pierce, RB Sachse, GW Blake, DR Cohen, RC Bertram, TH Perring, A Wooldridge, PJ Dibb, J Huey, G Hudman, RC Turquety, S Emmons, LK Flocke, F Tang, Y Carmichael, GR Horowitz, LW AF Singh, H. B. Salas, L. Herlth, D. Kolyer, R. Czech, E. Avery, M. Crawford, J. H. Pierce, R. B. Sachse, G. W. Blake, D. R. Cohen, R. C. Bertram, T. H. Perring, A. Wooldridge, P. J. Dibb, J. Huey, G. Hudman, R. C. Turquety, S. Emmons, L. K. Flocke, F. Tang, Y. Carmichael, G. R. Horowitz, L. W. TI Reactive nitrogen distribution and partitioning in the North American troposphere and lowermost stratosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID REGIONAL AIR-QUALITY; IN-SITU MEASUREMENTS; AIRBORNE MEASUREMENTS; AIRCRAFT EMISSIONS; PACIFIC-OCEAN; CHEMISTRY; OZONE; NOX; CONSTRAINTS; PARTICLES AB [1] A comprehensive group of reactive nitrogen species (NO, NO2, HNO3, HO2NO2, PANs, alkyl nitrates, and aerosol-NO3-) were measured over North America during July/August 2004 from the NASA DC-8 platform (0.1-12 km). Nitrogen containing tracers of biomass combustion (HCN and CH3CN) were also measured along with a host of other gaseous (CO, VOC, OVOC, halocarbon) and aerosol tracers. Clean background air as well as air with influences from biogenic emissions, anthropogenic pollution, biomass combustion, convection, lightning, and the stratosphere was sampled over the continental United States, the Atlantic, and the Pacific. The North American upper troposphere (UT) was found to be greatly influenced by both lightning NOx and surface pollution lofted via convection and contained elevated concentrations of PAN, ozone, hydrocarbons, and NOx. Observational data suggest that lightning was a far greater contributor to NOx in the UT than previously believed. PAN provided a dominant reservoir of reactive nitrogen in the UT while nitric acid dominated in the lower troposphere (LT). Peroxynitric acid (HO2NO2) was present in sizable concentrations peaking at around 8 km. Aerosol nitrate appeared to be mostly contained in large soil based particles in the LT. Plumes from Alaskan fires contained large amounts of PAN and aerosol nitrate but little enhancement in ozone. A comparison of observed data with simulations from four 3-D models shows significant differences between observations and models as well as among models. We investigate the partitioning and interplay of the reactive nitrogen species within characteristic air masses and further examine their role in ozone formation. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 92717 USA. Univ Calif Berkeley, Dept Earth & Planetary Sci, Berkeley, CA 92717 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Natl Ctr Atmospher Res, Boulder, CO 80301 USA. Univ Iowa, Dept Chem & Biochem Engn, Iowa City, IA 52242 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Singh, HB (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM eczech@mail.arc.nasa.gov RI Horowitz, Larry/D-8048-2014; Emmons, Louisa/R-8922-2016; Perring, Anne/G-4597-2013; Cohen, Ronald/A-8842-2011; Pierce, Robert Bradley/F-5609-2010; Hudman, Rynda/C-6118-2009; Crawford, James/L-6632-2013 OI Horowitz, Larry/0000-0002-5886-3314; Emmons, Louisa/0000-0003-2325-6212; Perring, Anne/0000-0003-2231-7503; Cohen, Ronald/0000-0001-6617-7691; Pierce, Robert Bradley/0000-0002-2767-1643; Crawford, James/0000-0002-6982-0934 NR 50 TC 52 Z9 52 U1 3 U2 26 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 4 PY 2007 VL 112 IS D12 AR D12S04 DI 10.1029/2006JD007664 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155MH UT WOS:000245581000001 ER PT J AU Singleton, CS Randall, CE Harvey, VL Chipperfield, MP Feng, W Manney, GL Froidevaux, L Boone, CD Bernath, PF Walker, KA McElroy, CT Hoppel, KW AF Singleton, C. S. Randall, C. E. Harvey, V. L. Chipperfield, M. P. Feng, W. Manney, G. L. Froidevaux, L. Boone, C. D. Bernath, P. F. Walker, K. A. McElroy, C. T. Hoppel, K. W. TI Quantifying Arctic ozone loss during the 2004-2005 winter using satellite observations and a chemical transport model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID POLAR VORTEX; 3-DIMENSIONAL MODEL; STRATOSPHERIC OZONE; AURA SATELLITE; UARS DATA; EOS MLS; POAM-II; DEPLETION; VALIDATION; CLIMATOLOGY AB During the last decade, much attention has been placed on quantifying and modeling Arctic stratospheric O-3 loss. At issue in particular is the reliability of models for simulating the loss under variable dynamical conditions in the Arctic region. This paper describes inferred O-3 loss calculations for the 2004 - 2005 Arctic winter using data from four solar occultation satellite instruments, as well as the Earth Observing System Microwave Limb Sounder (EOS MLS). O-3 loss is quantified with the "Chemical Transport Model (CTM) passive subtraction" approach, using a passive O-3 tracer field from the SLIMCAT CTM. The 2004 - 2005 Arctic winter was moderately active dynamically, but was still one of the coldest Arctic winters on record, with prime conditions for O-3 loss. Loss estimates inferred from all of the different satellite instruments peaked in mid-March at 450 K between 2 - 2.3 ppmv, slightly less than similar estimations for the cold 1999 - 2000 winter. The SLIMCAT CTM was also used to simulate O-3 for the 2004 - 2005 winter. In March, near 450 K, the model O-3 was 0.3 ppmv (similar to 10 - 15%) lower than the observations, leading to a maximum O-3 loss that was 10 - 15% larger than that inferred from observations, using the passive subtraction approach. Modeled loss maximized around the same time as that inferred from observations. Although some discrepancies between the observed and modeled O-3 remain, the level of agreement presented here shows that the SLIMCAT CTM was able to satisfactorily simulate O-3 and polar O-3 loss during the dynamically active 2004 - 2005 Arctic winter. C1 Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Univ Leeds, Sch Earth & Environm, Inst Atmospher Sci, Leeds LS2 9JT, W Yorkshire, England. CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. New Mexico Inst Min & Technol, Dept Phys, Las Vegas, NV USA. Univ Waterloo, Dept Chem, Waterloo, ON N2L 3G1, Canada. Environm Canada, Meteorol Serv Canada, Downsview, ON, Canada. Univ Toronto, Dept Phys, Toronto, ON, Canada. USN, Res Lab, Remote Sensing Phys Branch, Washington, DC 20375 USA. RP Singleton, CS (reprint author), Univ Colorado, Atmospher & Space Phys Lab, UCB 392, Boulder, CO 80309 USA. EM cynthia.singleton@lasp.colorado.edu RI FENG, WUHU/B-8327-2008; Bernath, Peter/B-6567-2012; Chipperfield, Martyn/H-6359-2013; Randall, Cora/L-8760-2014 OI FENG, WUHU/0000-0002-9907-9120; Bernath, Peter/0000-0002-1255-396X; Chipperfield, Martyn/0000-0002-6803-4149; Randall, Cora/0000-0002-4313-4397 NR 45 TC 26 Z9 26 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 4 PY 2007 VL 112 IS D7 AR D07304 DI 10.1029/2006JD007463 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155LV UT WOS:000245579800001 ER PT J AU Brakenridge, GR Nghiem, SV Anderson, E Mic, R AF Brakenridge, G. Robert Nghiem, Son V. Anderson, Elaine Mic, Rodica TI Orbital microwave measurement of river discharge and ice status SO WATER RESOURCES RESEARCH LA English DT Article ID SYNTHETIC-APERTURE RADAR; INUNDATION AREA; AMSR-E; WATER; MODEL; FREQUENCIES AB Satellite passive microwave sensors provide global coverage of the Earth's land surface on a near-daily basis without severe interference from cloud cover. Using a strategy first developed for wide-area optical sensors, and in conjunction with even limited ground-based discharge information, such microwave data can be used to estimate river discharge changes, river ice status, and watershed runoff. Water surface area in a river reach increases as flow widens, and any temporally calibrated observation sensitive to changing water area monitors discharge. The sensor spatial resolution is less important than the scene-to-scene calibration and the contrast in upwelling radiance between water and land. We use the Advanced Microwave Scanning Radiometer (AMSR-E) band at 36.5 GHz, descending orbit, horizontal polarization, and the resampled Level-3 daily global data product. The discharge estimator HR is a ratio of calibration-target radiance (expressed as brightness temperature), for a local land parcel unaffected by the river, to measurement- target brightness temperature, for a pixel centered over the river. At midlatitudes, pixel dimensions are approximately 25 km. Because of low emission from water surfaces, HR increases with discharge as in-pixel water area expands. It increases sharply once overbank flow conditions occur. River ice-cover is also detectable. The sensitivity and accuracy of the orbital measurements is tested along U. S. rivers monitored by in situ gaging stations, with favorable results. Other tests demonstrate that for seasonally variable rivers, AMSR-E can provide useful international measurements of daily river discharge even if only fragmentary monthly mean discharge data are available for calibration. C1 Dartmouth Coll, Dept Geog, Dartmouth Flood Observ, Hanover, NH 03755 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Inst Hydrol & Water Management, Bucharest 031686, Romania. RP Brakenridge, GR (reprint author), Dartmouth Coll, Dept Geog, Dartmouth Flood Observ, Hanover, NH 03755 USA. EM robert.brakenridge@dartmouth.edu; son.v.nghiem@jpl.nasa.gov; rodica.mic@hidro.ro NR 37 TC 55 Z9 56 U1 0 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD APR 4 PY 2007 VL 43 IS 4 AR W04405 DI 10.1029/2006WR005238 PG 16 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 155NR UT WOS:000245584600004 ER PT J AU Aragao, LEOC Malhi, Y Roman-Cuesta, RM Saatchi, S Anderson, LO Shimabukuro, YE AF Aragao, Luiz Eduardo O. C. Malhi, Yadvinder Roman-Cuesta, Rosa Maria Saatchi, Sassan Anderson, Liana O. Shimabukuro, Yosio Edemir TI Spatial patterns and fire response of recent Amazonian droughts SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID POSITIVE FEEDBACKS; TROPICAL FOREST; BASIN; VARIABILITY; CLIMATE; RAINFALL; PACIFIC; TRENDS AB There has been an increasing awareness of the possibility of climate change causing increased drought frequency in Amazonia, with ensuing impacts on ecosystems and human populations. This debate has been brought into focus by the 1997/1998 and 2005 Amazonian droughts. We analysed the spatial extent of these droughts and fire response to the 2005 drought with TRMM and NOAA-12 data, respectively. Both droughts had distinct fingerprints. The 2005 drought was characterized by its intensification throughout the dry season in south-western Amazonia. During 2005 the annual cumulative number of hot pixels in Amazonia increased 33% in relation to the 1999 - 2005 mean. In the Brazilian state of Acre, at the epicentre of the 2005 drought, the area of leakage forest fires was more than five times greater than the area directly deforested. Fire leakage into flammable forests may be the major agent of biome transformation in the event of increasing drought frequency. C1 Univ Oxford, Ctr Environm, Environm Change Inst, Oxford OX1 3QY, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Brazilian Inst Space Res, BR-12227010 Sao Jose Dos Campos, Brazil. RP Aragao, LEOC (reprint author), Univ Oxford, Ctr Environm, Environm Change Inst, S Parks Rd, Oxford OX1 3QY, England. EM laragao@ouce.ox.ac.uk RI aragao, luiz/G-8387-2012; Anderson, Liana/G-8389-2012 OI aragao, luiz/0000-0002-4134-6708; Anderson, Liana/0000-0001-9545-5136 NR 22 TC 154 Z9 156 U1 5 U2 43 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 3 PY 2007 VL 34 IS 7 AR L07701 DI 10.1029/2006GL028946 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 155LG UT WOS:000245578300004 ER PT J AU Turquety, S Logan, JA Jacob, DJ Hudman, RC Leung, FY Heald, CL Yantosca, RM Wu, SL Emmons, LK Edwards, DP Sachse, GW AF Turquety, Solene Logan, Jennifer A. Jacob, Daniel J. Hudman, Rynda C. Leung, Fok Yan Heald, Colette L. Yantosca, Robert M. Wu, Shiliang Emmons, Louisa K. Edwards, David P. Sachse, Glen W. TI Inventory of boreal fire emissions for North America in 2004: Importance of peat burning and pyroconvective injection SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CANADIAN FOREST-FIRES; TRANSFORM INFRARED-SPECTROSCOPY; TROPOSPHERE MOPITT INSTRUMENT; BLACK SPRUCE FOREST; ORGANIC-MATTER LOST; CARBON-MONOXIDE; UNITED-STATES; INTERANNUAL VARIABILITY; AIRCRAFT OBSERVATIONS; TERRA SATELLITE AB The summer of 2004 was one of the largest fire seasons on record for Alaska and western Canada. We construct a daily bottom-up fire emission inventory for that season, including consideration of peat burning and high-altitude (buoyant) injection, and evaluate it in a global chemical transport model (the GEOS-Chem CTM) simulation of CO through comparison with MOPITT satellite and ICARTT aircraft observations. The inventory is constructed by combining daily area burned reports and MODIS fire hot spots with estimates of fuel consumption and emission factors based on ecosystem type. We estimate the contribution from peat burning using drainage and peat distribution maps for Alaska and Canada; 17% of the reported 5.1 x 10(6) ha burned were located in peatlands in 2004. Our total estimate of North American fire emissions during the summer of 2004 is 30 Tg CO, including 11 Tg from peat. Including peat burning in the GEOS-Chem simulation improves agreement with MOPITT observations. The long-range transport of fire plumes observed by MOPITT suggests that the largest fires injected a significant fraction of their emissions in the upper troposphere. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Univ Calif Berkeley, Ctr Atmospher Sci, Berkeley, CA 94720 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Paris 06, Inst Pierre Simon Laplace, Serv Aeron, F-75005 Paris, France. RP Turquety, S (reprint author), Natl Ctr Atmospher Res, Div Atmospher Chem, POB 3000, Boulder, CO 80307 USA. EM stu@aero.jussieu.fr RI Heald, Colette/A-6813-2011; Hudman, Rynda/C-6118-2009; Yantosca, Robert/F-7920-2014; Chem, GEOS/C-5595-2014; Emmons, Louisa/R-8922-2016 OI Yantosca, Robert/0000-0003-3781-1870; Emmons, Louisa/0000-0003-2325-6212 NR 99 TC 119 Z9 121 U1 0 U2 14 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 3 PY 2007 VL 112 IS D12 AR D12S03 DI 10.1029/2006JD007281 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155MF UT WOS:000245580800001 ER PT J AU Siscoe, G MacNeice, PJ Odstrcil, D AF Siscoe, G. MacNeice, P. J. Odstrcil, D. TI East-west asymmetry in coronal mass ejection geoeffectiveness SO SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS LA English DT Article ID MAGNETIC-FIELD; GEOMAGNETIC STORMS; SOLAR-WIND; EARTH AB [1] This paper extends the domain of applicability of the Gosling-McComas space weather forecast rule that applies to the postshock sheaths of fast coronal mass ejections at Earth (ICMEs). The rule is based on the draping of the sheath magnetic field around the ICME body. The original treatment considered only the radial-from-the-Sun component of the preshock interplanetary magnetic field ( IMF), which implied that the domain of applicability of the rule was the entire sheath region ahead of the leading face of the ICME. We show here that because of the generally prevailing Parker spiral orientation of the IMF, the domain of applicability of the rule is instead generally strongly shifted to the east side of the ICME sheath. We suggest that the eastward shift of the domain of applicability of the rule accounts for an observed greater geoeffectiveness of west hemisphere CMEs compared with east hemisphere CMEs. The approach used here to demonstrate the eastward shift of the region of potential ICME sheath geoeffectiveness, and thus to increase the accuracy of the forecast rule, is to present intensity contours of the geoeffective draping component of the IMF as computed by global MHD simulations. Since the shift depends only on a spiral magnetic field and a blunt object to drape it around, we demonstrate the generality of the principle on which the rule is based by treating both the case of the ICME and the case of Earth's magnetosphere. C1 [Siscoe, G.] Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. [MacNeice, P. J.] NASA, Goddard Space Flight Ctr, Community Coordinated Modeling Ctr, Greenbelt, MD 20771 USA. [Odstrcil, D.] NOAA, Space Environm Ctr, Boulder, CO 80303 USA. RP Siscoe, G (reprint author), Boston Univ, Ctr Space Phys, 725 Commonwealth Ave, Boston, MA 02215 USA. EM siscoe@bu.edu RI MacNeice, Peter/F-5587-2012 NR 16 TC 11 Z9 11 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 1542-7390 J9 SPACE WEATHER JI Space Weather PD APR 3 PY 2007 VL 5 IS 4 AR S04002 DI 10.1029/2006SW000286 PG 6 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 261IX UT WOS:000253073400002 ER PT J AU Doornbos, E Willis, P AF Doornbos, Eelco Willis, Pascal TI Analysis of DORIS range-rate residuals for TOPEX/Poseidon, Jason, Envisat and SPOT SO ACTA ASTRONAUTICA LA English DT Article DE DORIS; orbit determination; geodesy; systematic errors; antenna phase center variation ID ORBIT DETERMINATION; SEA-LEVEL; SYSTEM; ERRORS; PERTURBATIONS; SPACE; PHASE; GPS AB Three currently operational radar altimeter satellites are equipped with the Doppler orbitography and radiopositioning integrated by satellite (DORIS) tracking system for precise orbit determination and two more are already foreseen. Any systematic errors in their computed orbits could possibly adversely affect scientific products used in climate change studies, such as sea level and ice sheet heights. DORIS residuals, which can be interpreted as a measure of orbit determination performance, often show systematic errors. We have therefore analyzed long time series of DORIS range-rate residuals in order to investigate possible systematic errors common to all DORIS analysis strategies and software packages, either on a satellite or on a station basis. In particular, the investigation has focused on global DORIS data of six satellites (TOPEX, Jason, Envisat and SPOT 2, -4 and -5) and station-specific data for Fairbanks, Easter Island and Syowa Base. Large measurement errors when crossing the South Atlantic Anomaly are easily detected in the DORIS residuals of Jason, while Envisat residuals show the most prominent evidence of multipath interference and the effect of a flight software update. Particularly, large errors were also found in low-elevation data. (c) 2006 Elsevier Ltd. All rights reserved. C1 Delft Univ Technol, Fac Aerosp Engn, Dept Earth Observat & Space Syst, NL-2629 HS Delft, Netherlands. Inst Geog Natl, F-94160 St Mande, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Doornbos, E (reprint author), Delft Univ Technol, Fac Aerosp Engn, Dept Earth Observat & Space Syst, Kluyverweg 1, NL-2629 HS Delft, Netherlands. EM e.n.doornbos@tudelft.nl RI Willis, Pascal/A-8046-2008 OI Willis, Pascal/0000-0002-3257-0679 NR 40 TC 12 Z9 14 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD APR-MAY PY 2007 VL 60 IS 8-9 BP 611 EP 621 DI 10.1016/j.actaastro.2006.07.012 PG 11 WC Engineering, Aerospace SC Engineering GA 147EV UT WOS:000244987100001 ER PT J AU Sarosi, PM Srinivasan, R Eggeler, GF Nathal, MV Mills, MJ AF Sarosi, P. M. Srinivasan, R. Eggeler, G. F. Nathal, M. V. Mills, M. J. TI Observations of a{010} dislocations during the high-temperature creep of Ni-based superalloy single crystals deformed along the [001] orientation SO ACTA MATERIALIA LA English DT Article DE nickel-base superalloy; NASAIR; creep; 001; dislocation ID LOW-STRESS CREEP; GAMMA-GAMMA' INTERFACES; UNIAXIAL STRESS; DRIVING-FORCE; ALLOY; GAMMA'-PHASE; MORPHOLOGY; DEFORMATION; MECHANISM; BEHAVIOUR AB A NASAIR-100 superalloy single crystal was tested in tension creep at 1000 degrees C at a stress of 148 MPa, for a time period of 20 It and to a strain of 1.1%. Analysis of the resulting dislocation structures after rafting was completed reveals the frequent presence of all three types of a 010 dislocations in the gamma' particles. Two of these families experience no resolved forces due to the applied stress. It is proposed that these a 010 dislocations form as a result of the combination of two dissimilar a/2 011 dislocations entering from gamma channels. The possible driving forces for the movement of these a 010 dislocations are discussed, and a novel recovery mechanism during creep of rafted microstructures is introduced on the basis of these observations. (c) 2007 Published by Elsevier Ltd on behalf of Acta Materialia Inc. C1 Ohio State Univ, Dept Mat Sci & Engn, Columbus, OH 43210 USA. GE India Technol Ctr, Bangalore 560066, Karnataka, India. Ruhr Univ Bochum, Fak Maschinenbau, Inst Werkstoffe, Lehrstuhl Werkstoffwissensch, D-44780 Bochum, Germany. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Sarosi, PM (reprint author), Ohio State Univ, Dept Mat Sci & Engn, 116 W 19Th Ave, Columbus, OH 43210 USA. EM sarosi@matsceng.ohio-state.edu RI Eggeler, Gunther/R-9833-2016 NR 45 TC 38 Z9 38 U1 2 U2 21 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD APR PY 2007 VL 55 IS 7 BP 2509 EP 2518 DI 10.1016/j.actamat.2006.11.045 PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 164ML UT WOS:000246238000028 ER PT J AU Xiao, X Hassan, HA Edwards, JR Gaffney, RL AF Xiao, X. Hassan, H. A. Edwards, J. R. Gaffney, R. L., Jr. TI Role of turbulent Prandtl numbers on heat flux at hypersonic Mach numbers SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 43rd Aerospace Sciences Meeting and Exhibit CY JAN 10-13, 2005 CL Reno, NV SP AIAA ID LAYER INTERACTIONS; MODEL; FLOW AB A new turbulence model suited for calculating the turbulent Prandtl number as part of the solution is presented. Because of the high Reynolds numbers involved, a formulation based on the Reynolds-averaged Navier-Stokes equations is developed. The model is based on a set of two equations: one governing the variance of the enthalpy and the other governing its dissipation rate. These equations were derived from the exact energy equation and thus take into consideration compressibility and dissipation terms. The model is used to study three cases involving shock-wave/boundary-layer interaction at Mach numbers of 9.22, 8.18, and 5.0. In general, heat transfer prediction for separated flows showed improvement over traditional turbulence models in which the turbulent Prandtl number is assumed constant. It is concluded that using a model that calculates the turbulent Prandtl number as part of the solution is a key to bridging the gap between theory and experiment for hypersonic flows dominated by strong shock-wave/boundary-layer interactions. C1 N Carolina State Univ, Dept Mech & Aerosp Engn, Raleigh, NC 27695 USA. NASA, Langley Res Ctr, Hyperson Air Breathing Propuls Branch, Hampton, VA 23681 USA. RP Xiao, X (reprint author), N Carolina State Univ, Dept Mech & Aerosp Engn, Raleigh, NC 27695 USA. NR 21 TC 8 Z9 8 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD APR PY 2007 VL 45 IS 4 BP 806 EP 813 DI 10.2514/1.2144 PG 8 WC Engineering, Aerospace SC Engineering GA 152FB UT WOS:000245345400009 ER PT J AU O'Byrne, S Danehy, PM Tedder, SA Cutler, AD AF O'Byrne, S. Danehy, P. M. Tedder, S. A. Cutler, A. D. TI Dual-pump coherent anti-Stokes Raman scattering measurements in a supersonic combustor SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 42nd Aerospace Sciences Meeting and Exhibit CY JAN 05-08, 2004 CL Reno, NV SP Amer Inst Aeronaut & Astronaut ID TEMPERATURE-MEASUREMENTS; CARS THERMOMETRY; FLOW; JET AB The dual-pump coherent anti-Stokes Raman scattering (CARS) method was used to measure temperature and the mole fractions of N-2 and O-2 in a supersonic combustor. Experiments were conducted in NASA Langley Research Center's Direct-Connect Supersonic Combustion Test Facility. In this facility; H-2- and oxygen-enriched air burn to increase the enthalpy of the simulated air test gas. This gas is expanded through a Mach 2 nozzle and into a combustor model consisting of a short constant-area section followed by a small rearward-facing step and another constant-area section. At the end of this straight section, H-2 fuel is injected at Mach 2 and at a 30-deg angle with respect to the freestream. One wall of the duct then expands at a 3-deg angle for over 1 m. The ensuing combustion is probed optically through ports in the side of the combustor. Dual-pump CARS measurements were performed at the facility nozzle exit and at four planes downstream of fuel injection. Maps are presented of the mean temperature, as well as N-2 and O-2 mean mole-fraction fields. Correlations between fluctuations of the different measured parameters are also presented. C1 Univ New S Wales, Australian Def Force Acad, Canberra, ACT 2600, Australia. NASA, Langley Res Ctr, Hampton, VA 23681 USA. George Washington Univ, Newport News, VA 23602 USA. RP O'Byrne, S (reprint author), Univ New S Wales, Australian Def Force Acad, Canberra, ACT 2600, Australia. NR 33 TC 18 Z9 18 U1 0 U2 9 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD APR PY 2007 VL 45 IS 4 BP 922 EP 933 DI 10.2514/1.26768 PG 12 WC Engineering, Aerospace SC Engineering GA 152FB UT WOS:000245345400019 ER PT J AU Lewandowski, BE Kilgore, KL Gustafson, KJ AF Lewandowski, B. E. Kilgore, K. L. Gustafson, K. J. TI Design considerations for an implantable, muscle powered piezoelectric system for generating electrical power SO ANNALS OF BIOMEDICAL ENGINEERING LA English DT Article DE power generation; electrical stimulation; power conversion ID CONDITIONED SKELETAL-MUSCLE; ENERGY; STIMULATION AB A totally implantable piezoelectric generator system able to harness power from electrically activated muscle would augment the power systems of implanted functional electrical stimulation devices by reducing the number of battery replacement surgeries or by allowing periods of untethered functionality. The generator design contains no moving parts and uses a portion of the generated power for system operation. A software model of the system was developed and simulations performed to predict the output power as the system parameters were varied within their constraints. Mechanical forces that mimic muscle forces were experimentally applied to a piezoelectric generator to verify the accuracy of the simulations and to explore losses due to mechanical coupling. Depending on the selection of system parameters, software simulations predict that this generator concept can generate up to 690 mu W of power, which is greater than the power necessary to drive the generator, conservatively estimated to be 46 mu W. These results suggest that this concept has the potential to be an implantable, self-replenishing power source and warrants further investigation. C1 Case Western Reserve Univ, Neural Engn Ctr, Dept Biomed Engn, Cleveland, OH 44106 USA. NASA Glenn Res Ctr, Biosci & Technol Branch, Cleveland, OH 44135 USA. MetroHealth Med Ctr, Cleveland, OH 44109 USA. Vet Affairs Med Ctr, Louis Stokes Cleveland Dept, Cleveland, OH 44106 USA. RP Gustafson, KJ (reprint author), Case Western Reserve Univ, Neural Engn Ctr, Dept Biomed Engn, Wickenden Bldg,Rm 114,10900 Euclid Ave, Cleveland, OH 44106 USA. EM Kenneth.Gustafson@case.edu OI Kilgore, Kevin/0000-0002-2642-9855 FU NICHD NIH HHS [HD40298] NR 25 TC 14 Z9 14 U1 0 U2 4 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0090-6964 J9 ANN BIOMED ENG JI Ann. Biomed. Eng. PD APR PY 2007 VL 35 IS 4 BP 631 EP 641 DI 10.1007/s10439-007-9261-6 PG 11 WC Engineering, Biomedical SC Engineering GA 148MH UT WOS:000245078300011 PM 17295066 ER PT J AU La Duc, MT Dekas, A Osman, S Moissl, C Newcombe, D Venkateswaran, K AF La Duc, Myron T. Dekas, Anne Osman, Shariff Moissl, Christine Newcombe, David Venkateswaran, Kasthuri TI Isolation and characterization of bacteria capable of tolerating the extreme conditions of clean room environments SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID SPACECRAFT-ASSEMBLY FACILITY; MARS ODYSSEY SPACECRAFT; SP-NOV.; MICROBIOLOGICAL PROFILES; MICROBIAL DIVERSITY; VIKING SPACECRAFT; MICROORGANISMS; EVERYWHERE; RESISTANT; SURFACES AB In assessing the bacterial populations present in spacecraft assembly, spacecraft test, and launch preparation facilities, extremophilic bacteria (requiring severe conditions for growth) and extremotolerant bacteria (tolerant to extreme conditions) were isolated. Several cultivation approaches were employed to select for and identify bacteria that not only survive the nutrient-limiting conditions of clean room environments but can also withstand even more inhospitable environmental stresses. Due to their proximity to spacefaring objects, these bacteria pose a considerable risk for forward contamination of extraterrestrial sites. Samples collected from four geographically distinct National Aeronautics and Space Administration clean rooms were challenged with UV-C irradiation, 5% hydrogen peroxide, heat shock, pH extremes (pH 3.0 and 11.0), temperature extremes (4 degrees C to 65 degrees C), and hypersalinity (25% NaCl) prior to and/or during cultivation as a means of selecting for extremotolerant bacteria. Culture-independent approaches were employed to measure viable microbial (ATP-based) and total bacterial (quantitative PCR-based) burdens. Intracellular ATP concentrations suggested a viable microbial presence ranging from below detection limits to 10(6) cellS/m(2). However, only 0.1 to 55% of these viable cells were able to grow on defined culture medium. Isolated members of the Bacillaceae family were more physiologically diverse than those reported in previous studies, including thermophiles (Geobacillus), obligate anaerobes (Paenibacillus), and halotolerant, alkalophilic species (Oceanobacillus and Exiguobacterium). Non-spore-forming microbes (alpha- and beta-proteobacteria and actinobacteria) exhibiting tolerance to the selected stresses were also encountered. The multiassay cultivation approach employed herein enhances the current understanding of the physiological diversity of bacteria housed in these clean rooms and leads us to ponder the origin and means of translocation of thermophiles, anaerobes, and halotolerant alkalophiles into these environments. C1 CALTECH, Jet Propuls Lab, Biotechnol & Planetary Grp, Pasadena, CA 91109 USA. RP Venkateswaran, K (reprint author), Univ Regensburg, Lehrstuhl Mikrobiol & Archaeenzentrum, Univ Str 31, D-8400 Regensburg, Germany. EM kjvenkat@jpl.nasa.gov RI Moissl-Eichinger, Christine/A-6682-2015 OI Moissl-Eichinger, Christine/0000-0001-6755-6263 NR 38 TC 92 Z9 92 U1 3 U2 18 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD APR PY 2007 VL 73 IS 8 BP 2600 EP 2611 DI 10.1128/AEM.03007-06 PG 12 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 168RT UT WOS:000246542400023 PM 17308177 ER PT J AU Foster, JS Singh, AK Rothschild, LJ Sherman, LA AF Foster, Jamie S. Singh, Abhay K. Rothschild, Lynn J. Sherman, Louis A. TI Growth-phase dependent differential gene expression in Synechocystis sp strain PCC 6803 and regulation by a group 2 sigma factor SO ARCHIVES OF MICROBIOLOGY LA English DT Article DE cyanobacteria; light-limited growth; sigma factors; gene regulation; microarrays; IsiA; phrA ID SYNECHOCOCCUS-ELONGATUS PCC-7942; CYANOBACTERIAL CIRCADIAN CLOCK; CHLOROPHYLL-BINDING PROTEIN; ALTERNATIVE SIGMA-FACTORS; BACILLUS-SUBTILIS CELLS; STATIONARY-PHASE; ESCHERICHIA-COLI; PCC 6803; MICROARRAY ANALYSIS; HISTIDINE KINASE AB Cyanobacteria must continually alter their physiological growth state in response to changes in light intensity and their nutritional and physical environment. Under typical laboratory batch growth conditions, cyanobacteria grow exponentially, then transition to a light-limited stage of linear growth before finally reaching a non-growth stationary phase. In this study, we utilized DNA microarrays to profile the expression of genes in the cyanobacterium Synechocystis sp. PCC 6803 to compare exponential and linear growth. We also studied the importance of SigB, a group 2 sigma factor in this cyanobacterium, during the different growth phases. The transcription of approximately 10% of the genes in the wild type were different in the linear, compared to the exponential phase, and our results showed that: (1) many photosynthesis and regulatory genes had lowered transcript levels; (2) individual genes, such as sigH, phrA, and isiA, which encode a group 4 sigma factor, a DNA photolyase, and a Chl-binding protein, respectively, were strongly induced; and, (3) the loss of SigB significantly impacted the differential expression of genes and modulated the changes seen in the wild type in regard to photosynthesis, regulatory and the unknown genes. C1 Purdue Univ, Dept Sci Biol, W Lafayette, IN 47907 USA. Univ Florida, Space Life Sci Lab, Dept Microbiol & Cell Sci, Kennedy Space Ctr, FL 32899 USA. NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Moffett Field, CA 94035 USA. RP Sherman, LA (reprint author), Purdue Univ, Dept Sci Biol, 1392 Lilly Hall Life Sci, W Lafayette, IN 47907 USA. EM lsherman@purdue.edu FU NIAID NIH HHS [5F32AI056967-02] NR 74 TC 23 Z9 23 U1 0 U2 16 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0302-8933 J9 ARCH MICROBIOL JI Arch. Microbiol. PD APR PY 2007 VL 187 IS 4 BP 265 EP 279 DI 10.1007/s00203-006-0193-6 PG 15 WC Microbiology SC Microbiology GA 163JL UT WOS:000246155800002 PM 17160677 ER PT J AU Gilichinsky, DA Wilson, GS Friedmann, EI Mckay, CP Sletten, RS Rivkina, EM Vishnivetskaya, TA Erokhina, LG Ivanushkina, NE Kochkina, GA Shcherbakova, VA Soina, VS Spirina, EV Vorobyova, EA Fyodorov-Davydov, DG Hallet, B Ozerskaya, SM Sorokovikov, VA Laurinavichyus, KS Shatilovich, A Chanton, JP Ostroumov, VE Tiedje, JM AF Gilichinsky, D. A. Wilson, G. S. Friedmann, E. I. McKay, C. P. Sletten, R. S. Rivkina, E. M. Vishnivetskaya, T. A. Erokhina, L. G. Ivanushkina, N. E. Kochkina, G. A. Shcherbakova, V. A. Soina, V. S. Spirina, E. V. Vorobyova, E. A. Fyodorov-Davydov, D. G. Hallet, B. Ozerskaya, S. M. Sorokovikov, V. A. Laurinavichyus, K. S. Shatilovich, An. Chanton, J. P. Ostroumov, V. E. Tiedje, J. M. TI Microbial Populations in Antarctic permafrost: Biodiversity, state, age, and implication for astrobiology SO ASTROBIOLOGY LA English DT Review DE Antarctica; permafrost; viable microorganisms; ancient ecosystem; extraterrestrial model; astrobiology ID SOUTHERN VICTORIA-LAND; MCMURDO DRY VALLEYS; MIOCENE GLACIER ICE; BLUE-GREEN-ALGAE; BEACON VALLEY; EARLY MARS; MOLECULAR PHYLOGENY; ARCHAEAL ISOLATE; EAST ANTARCTICA; DOMINICAN AMBER AB Antarctic permafrost soils have not received as much geocryological and biological study as has been devoted to the ice sheet, though the permafrost is more stable and older and inhabited by more microbes. This makes these soils potentially more informative and a more significant microbial repository than ice sheets. Due to the stability of the subsurface physicochemical regime, Antarctic permafrost is not an extreme environment but a balanced natural one. Up to 104 viable cells/g, whose age presumably corresponds to the longevity of the permanently frozen state of the sediments, have been isolated from Antarctic permafrost. Along with the microbes, metabolic by-products are preserved. This presumed natural cryopreservation makes it possible to observe what may be the oldest microbial communities on Earth. Here, we describe the Antarctic permafrost habitat and biodiversity and provide a model for martian ecosystems. C1 Russian Acad Sci, Inst Physicochem & Biol Problems Soil Sci, Pushchino 142292, Moscow Region, Russia. Russian Acad Sci, Inst Basic Biol Problems, Pushchino 142292, Moscow Region, Russia. Russian Acad Sci, Inst Biochem & Physiol Microorganisms, Pushchino 142292, Moscow Region, Russia. Univ Otago, Dept Geol, Dunedin, New Zealand. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Univ Washington, Dept Earth & Space Sci, Seattle, WA 98195 USA. Univ Washington, Quaternary Res Ctr, Seattle, WA 98195 USA. Moscow MV Lomonosov State Univ, Dept Soil Sci, Moscow, Russia. Florida State Univ, Dept Oceanog, Tallahassee, FL 32306 USA. Michigan State Univ, Ctr Microbial Ecol, E Lansing, MI 48824 USA. RP Gilichinsky, DA (reprint author), Russian Acad Sci, Inst Physicochem & Biol Problems Soil Sci, Pushchino 142292, Moscow Region, Russia. EM dgilichin@issp.serpukhov.su RI Wilson, Gary/B-3803-2010; Vishnivetskaya, Tatiana/A-4488-2008; Rivkina, Elizaveta/O-5344-2014 OI Vishnivetskaya, Tatiana/0000-0002-0660-023X; Rivkina, Elizaveta/0000-0001-7949-8056 NR 172 TC 86 Z9 97 U1 10 U2 62 PU MARY ANN LIEBERT, INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 EI 1557-8070 J9 ASTROBIOLOGY JI Astrobiology PD APR PY 2007 VL 7 IS 2 BP 275 EP 311 DI 10.1089/ast.2006.0012 PG 37 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 170RC UT WOS:000246680700001 PM 17480161 ER PT J AU Summers, DP Khare, B AF Summers, David P. Khare, Bishun TI Nitrogen fixation on early Mars and other terrestrial planets: Experimental demonstration of abiotic fixation reactions to nitrite and nitrate SO ASTROBIOLOGY LA English DT Article DE nitrogen fixation; early Mars; early Earth; terrestrial planets; abiotic nitrogen fixation; prebiotic chemistry; early atmospheres; planetary habitability; nitrate; nitrite; nitric oxide; nitrous oxide; nitrogen dioxide; nitric acid; nitrogen; carbon dioxide; photochemistry ID EARTHS EARLY ATMOSPHERE; MERIDIANI-PLANUM; CARBON-DIOXIDE; OPPORTUNITY ROVER; OXIDATION-STATE; WATER; REDUCTION; EVOLUTION; HISTORY; AMMONIA AB Understanding the abiotic fixation of nitrogen is critical to understanding planetary evolution and the potential origin of life on terrestrial planets. Nitrogen, an essential biochemical element, is certainly necessary for life as we know it to arise. The loss of atmospheric nitrogen can result in an incapacity to sustain liquid water and impact planetary habitability and hydrological processes that shape the surface. However, our current understanding of how such fixation may occur is almost entirely theoretical. This work experimentally examines the chemistry, in both gas and aqueous phases, that would occur from the formation of NO and CO by the shock heating of a model carbon dioxide/nitrogen atmosphere such as is currently thought to exist on early terrestrial planets. The results show that two pathways exist for the abiotic fixation of nitrogen from the atmosphere into the crust: one via HNO and another via NO2. Fixation via HNO, which requires liquid water, could represent fixation on a planet with liquid water (and hence would also be a source of nitrogen for the origin of life). The pathway via NO2 does not require liquid water and shows that fixation could occur even when liquid water has been lost from a planet's surface (for example, continuing to remove nitrogen through NO2 reaction with ice, adsorbed water, etc.). C1 SETI Inst, Ames Res Ctr, NASA, Ctr Study Life Universe, Moffett Field, CA 94035 USA. RP Summers, DP (reprint author), SETI Inst, Ames Res Ctr, NASA, Ctr Study Life Universe, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM dsummers@mail.arc.nasa.gov NR 49 TC 27 Z9 27 U1 6 U2 20 PU MARY ANN LIEBERT INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD APR PY 2007 VL 7 IS 2 BP 333 EP 341 DI 10.1089/ast.2006.0032 PG 9 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 170RC UT WOS:000246680700004 PM 17480164 ER PT J AU La Duc, MT Benardini, JN Kempf, MJ Newcombe, DA Lubarsky, M Venkateswaran, K AF La Duc, Myron T. Benardini, James N. Kempf, Michael J. Newcombe, David A. Lubarsky, Michael Venkateswaran, Kasthuri TI Microbial diversity of Indian Ocean hydrothermal vent plumes: Microbes tolerant of desiccation, peroxide exposure, and ultraviolet and gamma-irradiation SO ASTROBIOLOGY LA English DT Article DE Archaea; hydrothermal vent; plume; Psychrobacter pacificensis; L0S3S-03b ID SPACECRAFT ASSEMBLY FACILITY; MARS ODYSSEY SPACECRAFT; SP NOV.; HYPERTHERMOPHILIC ARCHAEON; EPSILON-PROTEOBACTERIA; HYDROGEN-PEROXIDE; BACILLUS-PUMILUS; BLACK SMOKER; GEN. NOV.; SP. NOV. AB The microbial diversity of Kali chimney plumes, part of a hydrothermal vent field in the Rodriguez Triple Junction, Indian Ocean (depth approximately 2,240 m), was examined in an attempt to discover "extremotolerant" microorganisms that have evolved unique resistance capabilities to this harsh environment. Water and sediment samples were collected from the vent and from sediments located at various distances (2-20 m) away from and surrounding the chimney. Samples were screened for hypertolerant microbes that are able to withstand multiple stresses. A total of 46 isolates were selected for exposure to a number of perturbations, such as heat shock, desiccation, H2O2, and ultraviolet (UV) and gamma-irradiation. The survival of Psychrobacter sp. L0S3S-03b following exposure to > 1,000 J/m(2) UV254 radiation was particularly intriguing amid a background of varying levels of resistance. Vegetative. cells of this non-spore-forming microbe not only survived all of the treatments, but also exhibited a 90% lethal dose of 30 s when exposed to simulated martian UV radiation and a 100% lethal dose of 2 min when exposed to full spectrum UV, which is comparable to findings for bacterial endospores. C1 CALTECH, Jet Prop Lab, Biotechnol & Planetary Protect, Pasadena, CA 91109 USA. RP La Duc, MT (reprint author), CALTECH, Jet Prop Lab, Biotechnol & Planetary Protect, 4800 Oak Grove Dr,M-S 89, Pasadena, CA 91109 USA. EM mtladuc@jpl.nasa.gov NR 44 TC 8 Z9 9 U1 2 U2 13 PU MARY ANN LIEBERT INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD APR PY 2007 VL 7 IS 2 BP 416 EP 431 DI 10.1089/ast.2006.0060 PG 16 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 170RC UT WOS:000246680700009 PM 17480169 ER PT J AU Kovalev, YY Petrov, L Fomalont, EB Gordon, D AF Kovalev, Y. Y. Petrov, L. Fomalont, E. B. Gordon, D. TI The fifth VLBA calibrator survey: VCS5 SO ASTRONOMICAL JOURNAL LA English DT Article DE astrometry; catalogs; surveys ID NRAO PMN SURVEYS; CELESTIAL REFERENCE FRAME; RADIO-SOURCES; SOURCE CATALOG; SKY SURVEY; GHZ; QUASARS; SPECTRA AB This paper presents the fifth part of the Very Long Baseline Array (VLBA) Calibrator Survey (VCS), containing 569 sources not observed previously with very long baseline interferometry in geodetic or absolute astrometry programs. This campaign has two goals: (1) to observe additional sources that, together with previous survey results, form a complete sample, and (2) to find new strong sources suitable as phase calibrators. This VCS extension was based on three 24 hr VLBA observing sessions in 2005. It detected almost all extragalactic flat-spectrum sources with correlated flux density greater than 200 mJy at 8.6 GHz above declination -30 degrees that were not observed previously. Source positions with milliarcsecond accuracy were derived from astrometric analysis of ionosphere-free combinations of group delays determined from the 2.3 and 8.6 GHz frequency bands. The VCS5 catalog of source positions, plots of correlated flux density versus projected baseline length, contour plots, and FITS files of naturally weighted CLEAN images, as well as calibrated visibility function files, are available on the World Wide Web. C1 [Kovalev, Y. Y.] Natl Radio Astron Observ, Green Bank, WV USA. [Kovalev, Y. Y.] PN Lebedev Phys Inst, Ctr Astro Space, Moscow 117924, Russia. [Kovalev, Y. Y.] Max Planck Inst Radioastron, D-5300 Bonn, Germany. [Petrov, L.] Natl Astron Observ Japan, Astrogeodynam Observ, Mizusawa, Japan. [Fomalont, E. B.] Natl Radio Astron Observ, Charlottesville, VA USA. [Gordon, D.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kovalev, YY (reprint author), Natl Radio Astron Observ, Green Bank, WV USA. EM ykovalev@mpifr-bonn.mpg.de; leonid.petrov@lpetrov.net; efomalon@nrao.edu; dgg@leo.gsfc.nasa.gov RI Kovalev, Yuri/J-5671-2013 OI Kovalev, Yuri/0000-0001-9303-3263 NR 28 TC 72 Z9 72 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 EI 1538-3881 J9 ASTRON J JI Astron. J. PD APR PY 2007 VL 133 IS 4 BP 1236 EP 1242 DI 10.1086/511157 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 154YF UT WOS:000245543700004 ER PT J AU Greissl, J Meyer, MR Wilking, BA Fanetti, T Schneider, G Greene, TP Young, E AF Greissl, Julia Meyer, Michael R. Wilking, Bruce A. Fanetti, Tina Schneider, Glenn Greene, Thomas P. Young, Erick TI Hubble space telescope NICMOS observations of NGC 1333: The ratio of stars to substellar objects SO ASTRONOMICAL JOURNAL LA English DT Article DE infrared : stars; ISM : individual ( NGC 1333); stars : formation; stars : low-mass; brown dwarfs stars : luminosity function; mass function; stars : pre-main sequence ID INITIAL MASS FUNCTION; ORION-NEBULA-CLUSTER; T-TAURI STARS; BROWN DWARFS; FORMING REGION; STELLAR POPULATION; SOLAR NEIGHBORHOOD; SPECTRAL SEQUENCE; EMBEDDED-CLUSTER; PLEIADES CLUSTER AB We present an analysis of NICMOS photometry and low-resolution grism spectroscopy of low-mass stars and substellar objects in the young star-forming region NGC 1333. Our goal is to constrain the ratio of low-mass stars to substellar objects down to 20M(Jup) in the cluster, as well as constrain the cluster initial mass function (IMF) down to 30M(Jup), in combination with a previous survey of NGC 1333 by Wilking et al. Our survey covers four fields of 51.2" x; 51.2", centered on brown dwarf candidates previously identified in Wilking et al. We extend previous work based on the use of a water vapor index for spectral typing to wavelengths accessible with NICMOS on the Hubble Space Telescope. Spectral types were derived for the 14 brightest objects in our fields, ranging from <= M0 to M8, which, at the age of the cluster (0.3Myr), correspond to a range in mass of >= 0.25-0.02 M circle dot. In addition to the spectra, we present an analysis of the color-magnitude diagram using pre-main-sequence evolutionary models of D'Antona & Mazzitelli. Using an extinction-limited sample, we derive the ratio of low-mass stars to brown dwarfs. Comparisons of the observed ratio to that expected from the field IMF of Chabrier indicate that the two results are consistent. We combine our data with those of Wilking et al. to compute the ratio of intermediate-mass stars (0.1-1.0 M circle dot) to low-mass objects (0.03-0.1 M circle dot) in the cluster. We also report the discovery of a faint companion to the previously confirmed brown dwarf ASR 28, as well as a possible outflow surrounding ASR 16. If the faint companion is confirmed as a cluster member, it would have a mass of approximate to 5M(Jup) (mass ratio 0.15) at a projected distance of 350 AU, similar to that of 2MASS 1207-3923B. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. St Louis Univ, Dept Phys & Astron, St Louis, MO 63103 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Greissl, J (reprint author), Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. EM jgreissl@as.arizona.edu; mmeyer@as.arizona.edu NR 61 TC 21 Z9 21 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD APR PY 2007 VL 133 IS 4 BP 1321 EP 1330 DI 10.1086/510901 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 154YF UT WOS:000245543700012 ER PT J AU Porquet, D Reeves, JN Markowitz, A Turner, TJ Miller, L Nandra, K AF Porquet, D. Reeves, J. N. Markowitz, A. Turner, T. J. Miller, L. Nandra, K. TI An XMM-Newton view of the X-ray flat radio-quiet quasar PG1416-129 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : active; X-rays : galaxies; accretion, accretion discs; quasars : individual : PG 1416-129 ID ACTIVE GALACTIC NUCLEI; LINE SEYFERT-1 GALAXIES; RELATIVISTIC SPECTRAL FEATURES; INHOMOGENEOUS ACCRETION DISKS; ROTATING BLACK-HOLE; PHOTON BUBBLES; PG 1416-129; ABSORPTION; EMISSION; VARIABILITY AB Aims. The radio-quiet quasar PG1416-129 (z = 0.129) exhibits atypical optical and X-ray properties. Between 1990 and 2000, in response to its optical continuum decrease, the "classical" broad component of H beta almost completely disappeared, with a factor of 10 decrease in the line flux. In addition, the width of the broad component of the H beta line decreased significantly from 4000 km s(-1) to 1450 km s-1. In the X-ray band, this object was observed by Ginga in 1988 to have the hardest quasar photon index, with Gamma = 1.1 +/- 0.1. We present an XMM-Newton/EPIC observation of PG1416-129 performed in July 2004. Methods. We analyze the time-averaged pn spectrum of this quasar, as well as perform time-resolved spectroscopy. Results. We find that during the present XMM-Newton observation, PG1416-129 still has a rather hard photon index, both in the soft (0.2-2 keV) and hard (2-12 keV) energy ranges, compared to radio-quiet quasars (BLS1 and NLS1) but compatible with the photon index value found for radio-loud quasars. This object also shows long-term luminosity variability over 16 years by a factor of three with a variation of photon index from similar to 1.2 to similar to 1.8. In the soft energy band (0.2-2 keV), we found a very weak soft X-ray excess compared to other RQ quasars. The whole time averaged spectrum is fit very well either by X-ray ionized reflection from the accretion disk surface, by a warm absorber-emitter plus power-law, or by a smeared absorption/ emission from a relativistic outflow. While no constant narrow FeK line at 6.4 keV is observed, we find the possible presence of two non-simultaneous transient iron lines: a redshifted narrow iron line at about 5.5 keV (96.4% confidence level according to multi-trial Monte-Carlo simulations) at the beginning of this observation and the appearance of a line at 6.3-6.4 keV (99.1% c.l.) at the end of the observation. These variable lines could be generated by discrete hot-spots on the accretion disk surface. C1 Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA. Univ Oxford, Dept Phys, Oxford OX1 3RH, England. Univ London Imperial Coll Sci Technol & Med, Astrophys Grp, Blackett Lab, London SW7 2AW, England. RP Porquet, D (reprint author), Max Planck Inst Extraterr Phys, Postfach 1312, D-85741 Garching, Germany. EM dporquet@mpe.mpg.de OI Porquet, Delphine/0000-0001-9731-0352 NR 57 TC 4 Z9 4 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2007 VL 466 IS 1 BP 23 EP 30 DI 10.1051/0004-6361:20066048 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 156YV UT WOS:000245686700003 ER PT J AU Emery, JP Ore, CMD Cruikshank, DP Fernandez, YR Trilling, DE Stansberry, JA AF Emery, J. P. Ore, C. M. Dalle Cruikshank, D. P. Fernandez, Y. R. Trilling, D. E. Stansberry, J. A. TI Ices on (90377) Sedna: confirmation and compositional constraints SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE planets and satellites : individual : Sedna; Kuiper Belt; solar system : general; infrared : solar system ID TRANS-NEPTUNIAN OBJECTS; EXTENDED SCATTERED DISK; SPITZER-SPACE-TELESCOPE; INFRARED ARRAY CAMERA; OPTICAL-CONSTANTS; OORT CLOUD; CENTAURS; MICROWAVE; SURFACES; THOLINS AB We report measurements of reflectances of 90377 Sedna at lambda > 2.5 mu m using the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. Sedna orbits well beyond even the Kuiper Belt, with a perihelion distance of 76 AU, and is therefore very faint as viewed from Earth, despite its relatively large size. Previously published near-infrared spectra show possible signatures of CH4 and N-2 at similar to 2.3 and similar to 2.15 mu m, respectively. These and other ices also exhibit much stronger absorptions at. > 2.5 mu m, providing the motivation for the present work. We detected flux from Sedna at 3.6 and 4.5 mu m, but not at 5.8 or 8.0 mu m. The measured IRAC fluxes are converted to geometric albedos and combined with previous measurements of the visible and near-infrared spectra. Strong absorption at both 3.6 and 4.5 mu m (relative to the 2.0-2.5 mu m region) is readily apparent, confirming the presence of ices on the surface of Sedna. Spectral modeling of the full wavelength range (0.4-4.5 mu m) provides further constraints. We find that CH4 is required to fit the new data points, but that these new data points can not be adequately described with models containing CH4 and N-2 as the only ices. We suggest that H2O ice is also present. Several characteristics of the spectrum of Sedna suggest an absence of atmospheric volatile transport, in contrast to the large objects Eris and 2005 FY9. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Carl Sagan Ctr, Mountain View, CA 94043 USA. Univ Cent Florida, Dept Phys, Orlando, FL 32816 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Emery, JP (reprint author), NASA, Ames Res Ctr, Mail Stop 245-6, Moffett Field, CA 94035 USA. EM jemery@mail.arc.nasa.gov; cdalleore@mail.arc.nasa.gov; Dale.P.Cruikshank@nasa.gov; yfernandez@physics.ucf.edu; trilling@as.arizona.edu; stansber@as.arizona.edu OI Fernandez, Yanga/0000-0003-1156-9721 NR 33 TC 19 Z9 19 U1 0 U2 2 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2007 VL 466 IS 1 BP 395 EP 398 DI 10.1051/0004-6361:20067021 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 156YV UT WOS:000245686700039 ER PT J AU Chernyakova, M Neronov, A Courvoisier, TJL Turler, M Soldi, S Beckmann, V Lubinski, P Walter, R Page, KL Stuhlinger, M Staubert, R McHardy, IM AF Chernyakova, M. Neronov, A. Courvoisier, T. J. -L. Turler, M. Soldi, S. Beckmann, V. Lubinski, P. Walter, R. Page, K. L. Stuhlinger, M. Staubert, R. McHardy, I. M. TI 2003-2005 INTEGRAL and XMM-Newton observations of 3C 273 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE quasars : individual : 3C 273 ID ACTIVE GALACTIC NUCLEI; X-RAY-SPECTRUM; 3C 273; MULTIWAVELENGTH OBSERVATIONS; EMISSION; GALAXY; 3C273; LINE; JET AB Aims. The aim of this paper is to study the evolution of the broadband spectrum of one of the brightest and nearest quasars 3C 273. Methods. We analyze the data obtained during quasi-simultaneous INTEGRAL and XMM-Newton monitoring of the blazar 3C 273 in 2003-2005 in the UV, X-ray and soft gamma-ray bands and study the results in the context of the long-term evolution of the source. Results. The 0.2-100 keV spectrum of the source is well fitted by a combination of a soft cut-of power law and a hard power law. No improvement of the fit is achieved if one replaces the soft cut-of power law by either a blackbody, or a disk reflection model. During the observation period the source has reached the historically softest state in the hard X-ray domain with a photon index Gamma = 1.82 +/- 0.01. Comparing our data with available archived X-ray data from previous years, we find a secular evolution of the source toward softer X-ray emission (the photon index has increased by. Delta Gamma similar or equal to 0.3-0.4 over the last thirty years). We argue that existing theoretical models have to be significantly modified to account for the observed spectral evolution of the source. C1 INTEGRAL Sci Data Ctr, CH-1290 Versoix, Switzerland. Univ Geneva, Observ Geneva, CH-1290 Sauverny, Switzerland. NASA, Goddard Space Flight Ctr, Explorat Universe Div, Greenbelt, MD 20771 USA. Nicholas Copernicus Astron Ctr, PL-00716 Warsaw, Poland. Univ Leicester, UK Swift Sci Data Ctr, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. European Space Astron Ctr, XMM Newton Sci Operat Ctr, Madrid 28080, Spain. Inst Astron & Astrophys, D-72076 Tubingen, Germany. Univ Southampton, Sch Phys & Astron, Southampton SO17 1BJ, Hants, England. RP Chernyakova, M (reprint author), INTEGRAL Sci Data Ctr, Chemin Ecogia 16, CH-1290 Versoix, Switzerland. EM Masha.Chernyakova@obs.unige.ch NR 25 TC 19 Z9 19 U1 0 U2 2 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2007 VL 465 IS 1 BP 147 EP 156 DI 10.1051/0004-6361:20066285 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146JM UT WOS:000244930300020 ER PT J AU Boirin, L Keek, L Mendez, M Cumming, A In't Zand, JJM Cottam, J Paerels, F Lewin, WHG AF Boirin, L. Keek, L. Mendez, M. Cumming, A. In't Zand, J. J. M. Cottam, J. Paerels, F. Lewin, W. H. G. TI Discovery of X-ray burst triplets in EXO0748-676 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE X-rays : binaries; X-rays : bursts; X-rays : individuals : EXO 0748-676 ID ACCRETING NEUTRON-STARS; BINARY EXO 0748-676; XMM-NEWTON; ANGULAR-DISTRIBUTION; PERSISTENT EMISSION; NUCLEAR-PHYSICS; EXO-0748-676; ABSORPTION; EVOLUTION; RADIATION AB Type-I X-ray bursts are thermonuclear flashes that take place on the surface of accreting neutron stars. The wait time between consecutive bursts is set by the time required to accumulate the fuel needed to trigger a new burst; this is at least one hour. Sometimes secondary bursts are observed, approximately 10 min after the main burst. These short wait-time bursts are not yet understood. We observed the low-mass X-ray binary and X-ray burster EXO0748-676 with XMM-Newton for 158 h, during 7 uninterrupted observations lasting up to 30 h each. We detect 76 X-ray bursts. Most remarkably, 15 of these bursts occur in burst triplets, with wait times of 12 min between the three components of the triplet, T1, T2, and T3. We also detect 14 doublets with similar wait times between the two components of the doublet, D1 and D2. We characterize this behavior to try and obtain a better understanding of bursts with short wait times. We measure the burst peak flux, fluence, wait time and time profile, and study correlations between these parameters and with the persistent flux representing the mass accretion rate. (i) For all bursts with a long wait time, the fluence is tightly correlated with the wait time, whereas burst with short wait times generally have higher fluences than expected from this relationship; (ii) wait times tend to be longer after doublets and triplets; (iii) the time profile of single bursts, S1, and of the first burst in a double or triple burst, D1 and T1, always contains a slow component which is generally absent in the D2, T2 and T3 bursts; (iv) the peak flux is highest for S1, D1 and T1 bursts, but this is still a factor of 7 lower than the highest peak flux ever seen for a burst in this system; (v) the persistent flux, representing the mass accretion rate onto the neutron star, is about 1% of Eddington, which is among the lowest value so far measured for this system. The amount of energy per gram of accreted mass liberated during bursts is consistent with a fuel mixture of hydrogen-rich material. The characteristics of the bursts indicate that possibly all bursts in this system are hydrogen-ignited, in contrast with most other frequent X-ray bursters in which bursts are helium-ignited, but consistent with the low mass accretion rate in EXO0748-676. Possibly the hydrogen ignition is the determining factor for the occurrence of short wait-time bursts. For example the 12 min wait time may be associated with a nuclear beta decay timescale. C1 Univ Strasbourg 1, Observ Astron Strasbourg, F-67000 Strasbourg, France. Netherlands Inst Space Res, SRON, NL-3584 CA Utrecht, Netherlands. Univ Utrecht, Astron Inst, NL-3584 CC Utrecht, Netherlands. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada. NASA, Goddard Space Flight Ctr, Lab Xray Astrophys, Greenbelt, MD 20771 USA. Columbia Astrophys Lab, New York, NY 10027 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. RP Boirin, L (reprint author), Univ Strasbourg 1, Observ Astron Strasbourg, 11 Rue Univ, F-67000 Strasbourg, France. EM boirin@astro.u-strasbg.fr RI Cumming, Andrew/A-6082-2013; Mendez, Mariano/C-8011-2012 OI Cumming, Andrew/0000-0002-6335-0169; Mendez, Mariano/0000-0003-2187-2708 NR 41 TC 25 Z9 25 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2007 VL 465 IS 2 BP 559 EP U124 DI 10.1051/0004-6361:20066204 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 148WK UT WOS:000245107900024 ER PT J AU Zand, JJMI Jonker, PG Markwardt, CB AF Zand, J. J. M. in 't Jonker, P. G. Markwardt, C. B. TI Six new candidate ultracompact X-ray binaries SO ASTRONOMY & ASTROPHYSICS LA English DT Review DE X-rays : binaries; X-rays : bursts; accretion, accretion disks ID ACCRETING NEUTRON-STARS; FIELD CAMERAS OBSERVATIONS; XMM-NEWTON OBSERVATIONS; RICH DEGENERATE DONORS; GLOBULAR-CLUSTER M15; GALACTIC-CENTER; ORBITAL PERIOD; ANGULAR-DISTRIBUTION; OPTICAL COUNTERPART; DWARF-NOVA AB Ultracompact X-ray binaries ( UCXBs) appear able to sustain accretion onto the compact accretor at rates lower than in wider X-ray binaries. This may be understood by the smaller accretion disks in UCXBs: a lower X-ray luminosity suffices to keep a disk completely ionized through irradiation and, thus, keep the viscosity at a sufficiently high level to allow effective transport of matter to the compact object. We employ this distinguishing factor on data from RXTE and BeppoSAX to identify six new candidate UCXBs, thus increasing the population by one quarter. The candidates are drawn from the population of persistently accreting and type-I X-ray bursting low-mass X-ray binaries. The X-ray bursts establish the low-mass X-ray binary nature and provide a handle on the accretion rate. We find that the low accretion rates are supported by the long burst recurrence times and the hard X-ray spectra of the persistent emission as derived from the 2nd INTEGRAL catalog of soft gamma-ray sources. We discuss the peculiar light curves of some new UCXB candidates. C1 SRON, Netherland Inst Space Res, NL-3584 CA Utrecht, Netherlands. Univ Utrecht, Inst Astron, NL-3508 TA Utrecht, Netherlands. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Astroparticle Phys Lab, Greenbelt, MD 20771 USA. RP Zand, JJMI (reprint author), SRON, Netherland Inst Space Res, Sorbonnelaan 2, NL-3584 CA Utrecht, Netherlands. EM jeanz@sron.nl NR 111 TC 94 Z9 94 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2007 VL 465 IS 3 BP 953 EP 963 DI 10.1051/0004-6361:20066678 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 151LA UT WOS:000245290400028 ER PT J AU Caballero, I Kretschmar, P Santangelo, A Staubert, R Klochkov, D Camero, A Ferrigno, C Finger, MH Kreykenbohm, I McBride, VA Pottschmidt, K Rothschild, RE Schonherr, G Segreto, A Suchy, S Wilms, J Wilson, CA AF Caballero, I. Kretschmar, P. Santangelo, A. Staubert, R. Klochkov, D. Camero, A. Ferrigno, C. Finger, M. H. Kreykenbohm, I. McBride, V. A. Pottschmidt, K. Rothschild, R. E. Schoenherr, G. Segreto, A. Suchy, S. Wilms, J. Wilson, C. A. TI A0535+26 in the August/September 2005 outburst observed by RXTE and INTEGRAL SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE X-rays : binaries; stars : magnetic fields; stars : individual : A0535+26 ID RAY-TIMING-EXPLORER; PULSAR; PERFORMANCE; LUMINOSITY; A0535&26; BEPPOSAX; PERIOD AB Aims. In this Letter we present results from INTEGRAL and RXTE observations of the spectral and timing behavior of the High Mass X-ray Binary A0535+26 during its August/September 2005 normal (type I) outburst with an average flux F(5-100) keV similar to 400 mCrab. The search for cyclotron resonance scattering features (fundamental and harmonic) is one major focus of the paper. Methods. Our analysis is based on data from INTEGRAL and RXTE Target of Opportunity Observations performed during the outburst. The pulse period is determined. X-ray pulse profiles in different energy ranges are analyzed. The broad band INTEGRAL and RXTE pulse phase averaged X-ray spectra are studied. The evolution of the fundamental cyclotron line at different luminosities is analyzed. Results. The pulse period P is measured to be 103.39315(5) s at MJD 53614.5137. Two absorption features are detected in the phase averaged spectra at E-1 similar to 45 keV and E-2 similar to 100 keV. These can be interpreted as the fundamental cyclotron resonance scattering feature and its first harmonic and therefore the magnetic field can be estimated to be B similar to 4 x 10(12) G. C1 Inst Astron & Astrophys, D-72076 Tubingen, Germany. ESAC, INTEGRAL Sci Operat Ctr, Madrid 28080, Spain. Univ Valencia, GACE, Inst Ciencias Mat, Valencia 46071, Spain. Inst Astrofis Spaziale & Fis Cosm, IASF, INAF, I-90146 Palermo, Italy. Univ Space Res Assoc, George C Marshall Space Flight Ctr, NASA, Huntsville, AL 35812 USA. INTEGRAL Sci Data Ctr, CH-1290 Versoix, Switzerland. Univ Calif San Diego, CASS, La Jolla, CA 92093 USA. Dr Remeis Sternwarte Bamberg, D-96049 Bamberg, Germany. RP Caballero, I (reprint author), Inst Astron & Astrophys, Sand 1, D-72076 Tubingen, Germany. EM isabel@astro.uni-tuebingen.de RI Ferrigno, Carlo/H-4139-2012; Wilms, Joern/C-8116-2013; Kreykenbohm, Ingo/H-9659-2013; OI Wilms, Joern/0000-0003-2065-5410; Kreykenbohm, Ingo/0000-0001-7335-1803; Segreto, Alberto/0000-0001-7341-6603; Kretschmar, Peter/0000-0001-9840-2048 NR 38 TC 43 Z9 43 U1 0 U2 2 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2007 VL 465 IS 2 BP L21 EP L24 DI 10.1051/0004-6361:20067032 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 148WK UT WOS:000245107900002 ER PT J AU Uzpen, B Kobulnicky, HA Monson, AJ Pierce, MJ Clemens, DP Backman, DE Meade, MR Babler, BL Indebetouw, R Whitney, BA Watson, C Wolfire, MG Benjamin, RA Bracker, S Bania, TM Cohen, M Cyganowski, CJ Devine, KE Heitsch, F Jackson, JM Mathis, JS Mercer, EP Povich, MS Rho, J Robitaille, TP Sewilo, M Stolovy, SR Watson, DF Wolff, MJ Churchwell, E AF Uzpen, B. Kobulnicky, H. A. Monson, A. J. Pierce, M. J. Clemens, D. P. Backman, D. E. Meade, M. R. Babler, B. L. Indebetouw, R. Whitney, B. A. Watson, C. Wolfire, M. G. Benjamin, R. A. Bracker, S. Bania, T. M. Cohen, M. Cyganowski, C. J. Devine, K. E. Heitsch, F. Jackson, J. M. Mathis, J. S. Mercer, E. P. Povich, M. S. Rho, J. Robitaille, T. P. Sewilo, M. Stolovy, S. R. Watson, D. F. Wolff, M. J. Churchwell, E. TI The frequency of mid-infrared excess sources in galactic surveys SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; planetary systems ID MAIN-SEQUENCE STARS; SPITZER-SPACE-TELESCOPE; INFRARED ARRAY CAMERA; POINT-SOURCE CATALOG; HERBIG AE/BE STARS; VEGA-LIKE SYSTEMS; IRAS OBSERVATIONS; BETA-PICTORIS; GRAIN-GROWTH; NEARBY STARS AB We have identified 230 Tycho-2 Spectral Catalog stars that exhibit 8 mu m mid-IR extraphotospheric excesses in the MSX and Spitzer GLIMPSE surveys. Of these, 183 are either OB stars earlier than B8 in which the excess plausibly arises from a thermal bremsstrahlung component or evolved stars in which the excess may be explained by an atmospheric dust component. The remaining 47 stars have spectral classifications B8 or later and appear to be main-sequence or late pre-main-sequence objects harboring circumstellar disks. Six of the 47 stars exhibit multiple signatures characteristic of pre-main-sequence circumstellar disks, including emission lines, near-IR K-band excesses, and X-ray emission. Approximately one-third of the remaining 41 sources have emission lines suggesting relative youth. We modeled the excesses in 26 stars having two or more measurements in excess of the expected photospheres as single-component blackbodies. We determine probable disk temperatures and fractional IR luminosities in the range 191 K < T < 787 K and 3.9 x 10(-4) < L-IR/L-* < 2.7; 10(-1). The majority of our modeled sample (14 stars) have 10(-3) < L-IR/L-* < 10(-2) and are consistent with either transition disks or massive debris disks. These objects have fractional IR luminosities and temperatures between those of beta Pic-type debris disk systems (L-IR/L-* <= 10(-3)) and Class II pre-main-sequence systems (L-IR/L* similar or equal to 10(-1)). We estimate a lower limit on the fraction of Tycho-2 Spectral Catalog main-sequence stars having mid-IR, but not near-IR, excesses to be 1.0% +/- 0.3%. C1 Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. Boston Univ, Inst Astrophys Res, Boston, MA 02215 USA. NASA, Ames Res Ctr, SOFIA, Moffett Field, CA 94035 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. Space Sci Inst, Boulder, CO USA. Manchester Coll, Dept Phys, N Manchester, IN USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9AJ, Fife, Scotland. RP Uzpen, B (reprint author), Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. RI Bania, Thomas/H-2318-2014; OI Babler, Brian/0000-0002-6984-5752; Robitaille, Thomas/0000-0002-8642-1329 NR 64 TC 10 Z9 10 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2007 VL 658 IS 2 BP 1264 EP 1288 DI 10.1086/511736 PN 1 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 153BE UT WOS:000245405900050 ER PT J AU Trilling, DE Stansberry, JA Stapelfeldt, KR Rieke, GH Su, KYL Gray, RO Corbally, CJ Bryden, G Chen, CH Boden, A Beichman, CA AF Trilling, D. E. Stansberry, J. A. Stapelfeldt, K. R. Rieke, G. H. Su, K. Y. L. Gray, R. O. Corbally, C. J. Bryden, G. Chen, C. H. Boden, A. Beichman, C. A. TI Debris disks in main-sequence binary systems SO ASTROPHYSICAL JOURNAL LA English DT Review DE binaries : general; infrared : stars; planetary systems : formation ID SOLAR-TYPE STARS; SUBMILLIMETER CONTINUUM FLUX; MULTIBAND IMAGING PHOTOMETER; VEGA-LIKE STARS; NEARBY STARS; PLANETESIMAL ACCRETION; STELLAR MULTIPLICITY; SPECKLE OBSERVATIONS; CIRCUMBINARY DISK; BETA PHOTOMETRY AB We observed 69 A3-F8 main-sequence binary star systems using the Multiband Imaging Photometer for Spitzer on board the Spitzer Space Telescope. We find emission significantly in excess of predicted photospheric flux levels for 9(-3)(+4)% and 40(-6)(+7)% of these systems at 24 and 70 mu m, respectively. Twenty-two systems total have excess emission, including four systems that show excess emission at both wavelengths. A very large fraction ( nearly 60%) of observed binary systems with small (< 3 AU) separations have excess thermal emission. We interpret the observed infrared excesses as thermal emission from dust produced by collisions in planetesimal belts. The incidence of debris disks around main-sequence A3-F8 binaries is marginally higher than that for single old AFGK stars. Whatever combination of nature ( birth conditions of binary systems) and nurture ( interactions between the two stars) drives the evolution of debris disks in binary systems, it is clear that planetesimal formation is not inhibited to any great degree. We model these dust disks through fitting the spectral energy distributions and derive typical dust temperatures in the range 100-200 K and typical fractional luminosities around 10(-5), with both parameters similar to other Spitzer-discovered debris disks. Our calculated dust temperatures suggest that about half the excesses we observe are derived from circumbinary planetesimal belts and around one-third of the excesses clearly suggest circumstellar material. Three systems with excesses have dust in dynamically unstable regions, and we discuss possible scenarios for the origin of this short-lived dust. C1 Univ Arizona, Steward Observ, Vatican Observ Res Grp, Tucson, AZ 85721 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Appalachian State Univ, Dept Phys & Astron, Boone, NC 28608 USA. Natl Opt Astron Observ, Tucson, AZ 85719 USA. RP Trilling, DE (reprint author), Univ Arizona, Steward Observ, Vatican Observ Res Grp, Tucson, AZ 85721 USA. EM trilling@as.arizona.edu RI Stapelfeldt, Karl/D-2721-2012; OI Su, Kate/0000-0002-3532-5580 NR 101 TC 99 Z9 100 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2007 VL 658 IS 2 BP 1289 EP 1311 DI 10.1086/511668 PN 1 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 153BE UT WOS:000245405900051 ER PT J AU Moro-Martin, A Carpenter, JM Meyer, MR Hillenbrand, LA Malhotra, R Hollenbach, D Najita, J Henning, T Kim, JS Bouwman, J Silverstone, MD Hines, DC Wolf, S Pascucci, I Mamajek, EE Lunine, J AF Moro-Martin, Amaya Carpenter, John M. Meyer, Michael R. Hillenbrand, Lynne A. Malhotra, Renu Hollenbach, David Najita, Joan Henning, Thomas Kim, Jinyoung S. Bouwman, Jeroen Silverstone, Murray D. Hines, Dean C. Wolf, Sebastian Pascucci, Ilaria Mamajek, Eric E. Lunine, Jonathan TI Are debris disks and massive planets correlated? SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; Kuiper Belt; infrared : stars; planetary systems; stars : individual (HD 6434, HD 38529, HD 80606, HD 92788, HD 106252, HD 121504, HD 141937, HD 150706, HD 179949, HD 190228) ID SPITZER-SPACE-TELESCOPE; EXTRA-SOLAR PLANETS; INFRARED ARRAY CAMERA; KUIPER-BELT DUST; ABUNDANCE ANALYSES; GIANT PLANETS; PARENT STARS; F-DWARF; EVOLUTION; SYSTEMS AB Using data from the Spitzer Space Telescope Legacy Science Program Formation and Evolution of Planetary Systems (FEPS), we have searched for debris disks around nine FGK stars (2-10 Gyr), known from radial velocity ( RV) studies to have one or more massive planets. Only one of the sources, HD 38529, has excess emission above the stellar photosphere; at 70 mu m the signal-to-noise ratio in the excess is 4.7, while at lambda < 30 mu m there is no evidence of excess. The remaining sources show no excesses at any Spitzer wavelengths. Applying survival tests to the FEPS sample and the results for the FGK survey recently published in Bryden et al., we do not find a significant correlation between the frequency and properties of debris disks and the presence of close-in planets. We discuss possible reasons for the lack of a correlation. C1 Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Natl Opt Astron Observ, Tucson, AZ 85721 USA. Max Planck Inst Astron, Heidelberg, Germany. Space Sci Inst, Boulder, CO 80301 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Moro-Martin, A (reprint author), Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. EM amaya@astro.princeton.edu OI Malhotra, Renu/0000-0002-1226-3305 NR 68 TC 61 Z9 61 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2007 VL 658 IS 2 BP 1312 EP 1321 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 153BE UT WOS:000245405900052 ER PT J AU Serabyn, E Wallace, K Troy, M Mennesson, B Haguenauer, P Gappinger, R Burruss, R AF Serabyn, E. Wallace, K. Troy, M. Mennesson, B. Haguenauer, P. Gappinger, R. Burruss, R. TI Extreme adaptive optics imaging with a clear and well-corrected off-axis telescope subaperture SO ASTROPHYSICAL JOURNAL LA English DT Article DE instrumentation : adaptive optics ID 4-QUADRANT PHASE-MASK; EXTRASOLAR PLANETS; CORONAGRAPH AB Rather than using an adaptive optics (AO) system to correct a telescope's entire pupil, it can instead be used to more finely correct a smaller subaperture. Indeed, existing AO systems can be used to correct a subaperture 1/3 to 1/2 the size of a 5-10 m telescope to extreme adaptive optics (ExAO) levels. We discuss the potential performance of a clear off-axis well-corrected subaperture (WCS), and describe our initial imaging results with a 1.5 m diameter WCS on the Palomar Observatory's Hale Telescope. These include measured Strehl ratios of 0.92-0.94 in the infrared (2.17 mu m) and approximate to 0.12 in the B band, the latter allowing a binary of separation 0.34" to be easily resolved in the blue. Such performance levels enable a variety of novel observational modes, such as infrared ExAO, visible-wavelength AO, and high-contrast coronagraphy. One specific application suggested by the high Strehl ratio stability obtained (1%) is the measurement of planetary transits and eclipses. Also described is a simple "dark hole'' experiment carried out on a binary star, in which a comatic phase term was applied directly to the deformable mirror, in order to shift the diffraction rings to one side of the point-spread function. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Palomar Observ, Palomar Mt, CA 92060 USA. RP Serabyn, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 27 TC 33 Z9 33 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2007 VL 658 IS 2 BP 1386 EP 1391 DI 10.1086/511949 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 153BE UT WOS:000245405900060 ER PT J AU Stecker, FW Malkan, MA Scully, ST AF Stecker, F. W. Malkan, M. A. Scully, S. T. TI Intergalactic photon spectra from the far-IR to the UV lyman limit for 0 < z < 6 and the optical depth of the universe to high-energy gamma rays (vol 648, pg 774, 2006) SO ASTROPHYSICAL JOURNAL LA English DT Correction C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. James Madison Univ, Dept Phys, Harrisonburg, VA 22807 USA. RP Stecker, FW (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Stecker, Floyd/D-3169-2012 NR 1 TC 48 Z9 49 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2007 VL 658 IS 2 BP 1392 EP 1392 DI 10.1086/511738 PN 1 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 153BE UT WOS:000245405900061 ER PT J AU Brown, TM Smith, E Ferguson, HC Guhathakurta, P Kalirai, JS Rich, RM Renzini, A Sweigart, AV Reitzel, D Gilbert, KM Geha, M AF Brown, Thomas M. Smith, Ed Ferguson, Henry C. Guhathakurta, Puragra Kalirai, Jasonjot S. Rich, R. Michael Renzini, Alvio Sweigart, Allen V. Reitzel, David Gilbert, Karoline M. Geha, Marla TI The extended star formation history of the Andromeda spheroid at 21 kpc on the minor axis SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : halos; galaxies : individual (M31); galaxies : stellar content ID STELLAR POPULATIONS; GALAXY FORMATION; OUTER DISK; M31; HALO; METALLICITY; PHOTOMETRY; REIONIZATION; SUBSTRUCTURE; STREAM AB Using the Hubble Space Telescope Advanced Camera for Surveys, we have obtained deep optical images of a southeast minor-axis field in the Andromeda galaxy, 21 kpc from the nucleus. In both star counts and metallicity, this field represents a transition zone between the metal-rich, highly disturbed inner spheroid that dominates within 15 kpc and the metal-poor, diffuse population that dominates beyond 30 kpc. The color-magnitude diagram reaches well below the oldest main-sequence turnoff in the population, allowing a reconstruction of the star formation history in this field. Compared to the spheroid population at 11 kpc, the population at 21 kpc is similar to 1.3 Gyr older and similar to 0.2 dex more metal-poor, on average. However, like the population at 11 kpc, the population at 21 kpc exhibits an extended star formation history; one third of the stars are younger than 10 Gyr, although only a few percent are younger than 8 Gyr. The relatively wide range of metallicity and age is inconsistent with a single, rapid star formation episode and instead suggests that the spheroid even at 21 kpc is dominated by the debris of earlier merging events likely occurring more than 8 Gyr ago. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Osserv Astron Padova, I-35122 Padua, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Brown, TM (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. EM tbrown@stsci.edu; edsmith@stsci.edu; ferguson@stsci.edu; raja@ucolick.org; jkalirai@ucolick.org; rmr@astro.ucla.edu; arenzini@pd.astro.it; allen.v.sweigart@nasa.gov; reitzel@ucla.astro.edu; kgilbert@ucolick.org; marla.geha@nrc-cnrc.gc.ca OI Brown, Thomas/0000-0002-1793-9968 NR 25 TC 49 Z9 49 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2007 VL 658 IS 2 BP L95 EP L98 DI 10.1086/515395 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 153BF UT WOS:000245406000007 ER PT J AU Pontoppidan, KM Stapelfeldt, KR Blake, GA Van Dishoeck, EF Dullemond, CP AF Pontoppidan, Klaus M. Stapelfeldt, Karl R. Blake, Geoffrey A. Van Dishoeck, Ewine F. Dullemond, Cornelis P. TI Deep Spitzer spectroscopy of the "Flying Saucer" edge-on disk: Large grains beyond 50 AU SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; infrared : ISM; planetary systems : protoplanetary disks; stars : individual (2MASS J16281370-2431391); stars : pre-main-sequence ID T-TAURI STARS; PROTOPLANETARY DISKS; CIRCUMSTELLAR DISK; RADIATIVE-TRANSFER; OPTICAL-PROPERTIES; DARK CLOUD; DUST; TELESCOPE; EMISSION; JET AB We present deep Spitzer IRS low-resolution (lambda/Delta lambda similar to 100) 5 - 35 mu m spectroscopy of the edge-on disk the "Flying Saucer" (2MASS J16281370 - 2431391) in the Ophiuchus molecular cloud. The SED exhibits the characteristic two-peak shape predicted for a circumstellar disk viewed very close to edge-on. The short-wavelength peak is entirely due to photons scattered off the surface of the disk, while the long-wavelength peak is due to thermal emission from the disk itself. The Spitzer spectrum represents the first spectroscopic detection of scattered light out to 15 mu m from a bona fide, isolated edge-on disk around a T Tauri star. The depth and the wavelength of the mid-infrared "valley" of the SED give direct constraints on the size distribution of large grains in the disk. Using a 2D continuum radiative transfer model, we find that a significant amount of 5 - 10 mu m - sized grains is required in the surface layers of the disk at radii of 50 - 300 AU. The detection of relatively large grains in the upper layers implies that vertical mixing is effective, since grain growth models predict that the grains would otherwise settle deep in the disk on short timescales. Additionally, we tentatively detect the 9.66 mu m S(3) line of H-2 and the 11.2 mu m emission feature due to PAHs. C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Jet Prop Lab, Pasadena, CA 91109 USA. Leiden Observ, NL-2300 RA Leiden, Netherlands. Max Planck Inst Astron, D-69117 Heidelberg, Germany. RP Pontoppidan, KM (reprint author), CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. EM pontoppi@gps.caltech.edu; krs@exoplanet.jpl.nasa.gov; gab@gps.caltech.edu; ewine@strw.leidenuniv.nl; dullemon@mpia-hd.mpg.de RI Stapelfeldt, Karl/D-2721-2012; OI Dullemond, Cornelis/0000-0002-7078-5910 NR 27 TC 6 Z9 6 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2007 VL 658 IS 2 BP L111 EP L114 DI 10.1086/514817 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 153BF UT WOS:000245406000011 ER PT J AU Eisenhardt, PR De Propris, R Gonzalez, AH Stanford, SA Wang, M Dickinson, M AF Eisenhardt, Peter R. De Propris, Roberto Gonzalez, Anthony H. Stanford, S. A. Wang, Michael Dickinson, Mark TI Multiaperture UBVRIzJHK photometry of galaxies in the Coma Cluster SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE galaxies : clusters : individual (Coma); galaxies : evolution; galaxies : formation; galaxies : photometry ID COLOR-MAGNITUDE RELATION; INFRARED LUMINOSITY FUNCTION; HIGH-REDSHIFT CLUSTERS; STELLAR POPULATIONS; STAR-FORMATION; SPECTROSCOPIC DATA; ELLIPTIC GALAXIES; DISTANT CLUSTERS; NEARBY CLUSTERS; SPIRAL GALAXIES AB We present a set of UBVRIzJHK(s) photometry for 745 J + H-band-selected objects in a 22: 50; 29: 20 region centered on the core of the Coma Cluster. This includes 516 galaxies and is at least 80% complete to H 16, with a spectroscopically complete sample of 111 cluster members (nearly all with morphological classification) for H < 14: 5. For each object we present total Kron (1980) magnitudes and aperture photometry. As an example, we use these data to derive color-magnitude relations for Coma early-type galaxies, measure the intrinsic scatter of these relations and its dependence on galaxy mass, and address the issue of color gradients. We find that the color gradients are mild and that the intrinsic scatter about the color-magnitude relation is small (similar to 0.05 mag in U - V and less than similar to 0.03 in B - R, V - I, or J - K). There is no evidence that the intrinsic scatter varies with galaxy luminosity, suggesting that the cluster red sequence is established at early epochs over a range of similar to 100 in stellar mass. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Pasadena, CA 91125 USA. Cerro Tololo Interamer Observ, La Serena, Chile. Univ Florida, Dept Astron, Gainesville, FL 32611 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Kingbright Elect, Taipei, Taiwan. Natl Opt Astron Observ, Tucson, AZ 85719 USA. RP Eisenhardt, PR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 70 TC 43 Z9 43 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2007 VL 169 IS 2 BP 225 EP 238 DI 10.1086/511688 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 153BB UT WOS:000245405600003 ER PT J AU Hajian, AR Movit, SM Trofimov, D Balick, B Terzian, Y Knuth, KH Granquist-Fraser, D Huyser, KA Jalobeanu, A McIntosh, D Jaskot, AE Palen, S Panagia, N AF Hajian, Arsen R. Movit, Steven M. Trofimov, Denis Balick, Bruce Terzian, Yervant Knuth, Kevin H. Granquist-Fraser, Domhnull Huyser, Karen A. Jalobeanu, Andre McIntosh, Dawn Jaskot, Anne E. Palen, Stacy Panagia, Nino TI An atlas of [N II] and [O III] images and spectra of planetary nebulae SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE atlases; planetary nebulae : general ID EXPANSION; DISTANCE AB We present an atlas of Hubble Space Telescope images and ground-based, long-slit, narrowband spectra centered on the 6584 8 line of [N II] and the 5007 8 line of [O III]. The spectra were obtained for a variety of slit positions across each target (as shown on the images) in an effort to account for nonspherical nebular geometries in a robust manner. We have extended the prolate ellipsoidal shell model originally devised by Aaquist, Zhang, and Kwok to generate synthetic images, as well as long-slit spectra. Using this model, we have derived basic parameters for the subsample of PNe that present ellipsoidal appearances and regular kinematic patterns. We find differences between our parameters for the target PNe as compared to those of previous studies, which we attribute to increased spatial resolution for our image data and the inclusion of kinematic data in the model fits. The data and analysis presented in this paper can be combined with detections of nebular angular expansion rates to determine precise distances to the PN targets. C1 USN Observ, Dept Astrometry, Washington, DC 20392 USA. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Cornell Univ, Natl Astron & Ionosphere Ctr, Ithaca, NY 14853 USA. NASA, Ames Res Ctr, Intelligent Syst Div, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, QSS Grp Inc, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Educ Assoc, Moffett Field, CA 94035 USA. ULP, Ecole Natl Super Phys Strasbourg, CNRS, UMR 7005,LSIIT, Illkirch Graffenstaden, France. Williams Coll, Dept Astron, Williamstown, MA 01267 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Hajian, AR (reprint author), USN Observ, Dept Astrometry, Washington, DC 20392 USA. NR 11 TC 19 Z9 19 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2007 VL 169 IS 2 BP 289 EP 327 DI 10.1086/511767 PG 39 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 153BB UT WOS:000245405600006 ER PT J AU Ibrahim, AI Parke, WC Swank, JH Anwer, H Turolla, R Zane, S Hussein, MT El-Sherbini, T AF Ibrahim, Alaa I. Parke, William C. Swank, Jean H. Anwer, Hisham Turolla, Roberto Zane, Silvia Hussein, M. T. El-Sherbini, T. TI The continuum and line spectra of SGR 1806-20 bursts SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article DE pulsar : individual (SGR 1806-20); pulsars : general; stars : magnetic fields; stars : magnetar; gamma-rays bursts; X-rays : bursts ID CYCLOTRON-RESONANCE; SGR 1900+14; SGR-1900+14; DISCOVERY AB The defining property of Soft Gamma Repeaters is the emission of short, bright bursts of X-rays and soft gamma-rays. Here we present the continuum and line spectral properties of a large sample of bursts from SGR 1806-20, observed with the Proportional Counter Array (PCA) onboard the Rossi X-ray Timing Explorer (RXTE). Using 10 trail spectral models (5 single and 5 two component models), we find that the burst continua are best fitted by the single component models: cutoff power-law, optically thin bremsstrahlung, and simple power-law. Time resolved spectroscopy show that there are two absorption lines at similar to 5 keV and 20 keV in some bursts. The lines are relatively narrow with 90% upper limit on the line widths of 0.5-1.5 keV for the 5 keV feature and 1-3 keV for the 20 keV feature. Both lines have considerable equivalent width of 330-850 eV for the 5 keV feature and 780-2590 eV for the 20 keV feature. We examined whether theses spectral lines are dependent upon the choice of a particular continuum model and find no such dependence. Besides, we find that the 5 keV feature is pronounced with high confidence in the cumulative joint spectrum of the entire burst sample, both in the individual detectors of the PCA and in the co-added detectors spectrum. We confront the features against possible instrumental effects and find that none can account for the observed line properties. The two features do not seem to be connected to the same physical mechanism because (1) they do not always occur simultaneously, (2) while the 5 keV feature occurs at about the same energy, the 20 keV line centroid varies significantly from burst to burst over the range 18-22 keV, and (3) the centroid of the lines shows anti-correlated red/blue shifts. The transient appearance of the features in the individual bursts and in portions of the same burst, together with the spectral evolution seen in some bursts point to a complex emission mechanism that requires further investigation. C1 Cairo Univ, Dept Phys, Fac Sci, Cairo, Egypt. Cairo Univ, Fac Sci, Ctr Adv Interdisciplinary Sci, Div Astrophys, Cairo, Egypt. George Washington Univ, Dept Phys, Washington, DC 20052 USA. NASA, Goddard Space Flight Ctr, Astrophys Sci Div, Greenbelt, MD 20771 USA. Univ Padua, Dept Phys, Padua, Italy. UCL, Mullard Space Sci Lab, Surrey, England. RP Ibrahim, AI (reprint author), Cairo Univ, Dept Phys, Fac Sci, Cairo, Egypt. EM alaa@gwu.edu RI Ibrahim, Alaa/A-6250-2008; Swank, Jean/F-2693-2012 OI Ibrahim, Alaa/0000-0002-8791-7270; NR 13 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD APR PY 2007 VL 308 IS 1-4 BP 43 EP 50 DI 10.1007/s10509-007-9311-4 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 166BC UT WOS:000246351000006 ER PT J AU Baring, MG Harding, AK AF Baring, Matthew G. Harding, Alice K. TI Resonant compton upscattering in Anomalous X-ray Pulsars SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article DE non-thermal radiation mechanisms; magnetic fields; neutron stars; pulsars; X-rays ID STRONG MAGNETIC-FIELDS; ELECTRON-ENERGY LOSSES; SOFT GAMMA-REPEATERS; POLAR CAPS; THOMSON SCATTERING; 1E 1048.1-5937; PAIR CREATION; NEUTRON-STARS; 4U 0142+61; EMISSION AB A significant new development in the study of Anomalous X-ray Pulsars (AXPs) has been the recent discovery by INTEGRAL and RXTE of flat, hard X-ray components in three AXPs. These non-thermal spectral components differ dramatically from the steeper quasi-power-law tails seen in the classic X-ray band in these sources. A prime candidate mechanism for generating this new component is resonant, magnetic Compton upscattering. This process is very efficient in the strong magnetic fields present in AXPs. Here an introductory exploration of an inner magnetospheric model for upscattering of surface thermal X-rays in AXPs is offered, preparing the way for an investigation of whether such resonant upscattering can explain the 20-150 keV spectra seen by INTEGRAL. Characteristically flat emission spectra produced by non-thermal electrons injected in the emission region are computed using collision integrals. A relativistic QED scattering cross section is employed so that Klein-Nishina reductions are influential in determining the photon spectra and fluxes. Spectral results depend strongly on the magnetospheric locale of the scattering and the observer's orientation, which couple directly to the angular distributions of photons sampled. C1 Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA. NASA, Goddard Space Flight Ctr, Gravitat Astrophys Lab, Explorat Universe Div, Greenbelt, MD 20771 USA. RP Baring, MG (reprint author), Rice Univ, Dept Phys & Astron, MS 108,6100 Main St, Houston, TX 77005 USA. EM baring@rice.edu; harding@twinkie.gsfc.nasa.gov RI Harding, Alice/D-3160-2012 NR 41 TC 66 Z9 67 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD APR PY 2007 VL 308 IS 1-4 BP 109 EP 118 DI 10.1007/s10509-007-9326-x PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 166BC UT WOS:000246351000015 ER PT J AU Woods, PM Zavlin, VE Pavlov, GG AF Woods, Peter M. Zavlin, Vyacheslav E. Pavlov, George G. TI Evidence for a binary companion to the central compact object 1E 1207.4-5209 SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article DE X-rays; neutron stars : individual : (1E 1207.4-5209); supernovae : individual (PKS 1209-51/52) ID QUIET NEUTRON-STAR; X-RAY-EMISSION; SUPERNOVA-REMNANTS; RADIO PULSARS; SEARCH AB Unique among neutron stars, 1E 1207.4-5209 is an X-ray pulsar with a spin period of 424 ms that contains at least two strong absorption features in its energy spectrum. This neutron star is positionally coincident with the supernova remnant PKS 1209-51/52 and has been identified as a member of the growing class of radio-quiet compact central objects in supernova remnants. From previous observations with Chandra and XMM-Newton, it has been found that the 1E 1207.4-5209 is not spinning down monotonically as is common for young, isolated pulsars. The spin frequency history requires either strong, frequent glitches, the presence of a fall-back disk, or a binary companion. Here, we report on a sequence of seven XMM-Newton observations of 1E 1207.4-5209 performed during a 40 day window between 2005 June 22 and July 31. Due to unanticipated variance in the phase measurements during the observation period that was beyond the statistical uncertainties, we could not identify a unique phase-coherent timing solution. The three most probable timing solutions give frequency time derivatives of +0.9, -2.6, and +1.6 x 10(-12) Hz s(-1) (listed in descending order of significance). We conclude that the local frequency derivative during our XMM-Newton observing campaign differs from the long-term spin-down rate by more than an order of magnitude. This measurement effectively rules out glitch models for 1E 1207.4-5209. If the long-term spin frequency variations are caused by timing noise, the strength of the timing noise in 1E 1207.4-5209 is much stronger than in other pulsars with similar period derivatives. Therefore, it is highly unlikely that the spin variations are caused by the same physical process that causes timing noise in other isolated pulsars. The most plausible scenario for the observed spin irregularities is the presence of a binary companion to 1E 1207.4-5209. We identified a family of orbital solutions that are consistent with our phase-connected timing solution, archival frequency measurements, and constraints on the companions mass imposed by deep IR and optical observations. C1 Dynetics Inc, Huntsville, AL 35806 USA. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35805 USA. Penn State Univ, Davey Lab 525, University Pk, PA 16802 USA. RP Woods, PM (reprint author), Dynetics Inc, 1000 Explorer Blvd, Huntsville, AL 35806 USA. EM peter.woods@dynetics.com; vyacheslav.zavlin@msfc.nasa.gov; pavlov@astro.psu.edu NR 24 TC 8 Z9 8 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD APR PY 2007 VL 308 IS 1-4 BP 239 EP 246 DI 10.1007/s10509-007-9339-5 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 166BC UT WOS:000246351000032 ER PT J AU Zavlin, VE AF Zavlin, Vyacheslav E. TI Studying millisecond pulsars in X-rays SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article DE X-rays; neutron stars; millisecond pulsars ID RADIATION PAIR FRONTS; HIGH-ENERGY EMISSION; PSR J0218+4232; NEUTRON-STAR; BOW SHOCK; OUTER MAGNETOSPHERE; TIMING OBSERVATIONS; RADIO PULSARS; SPIN-DOWN; CHANDRA AB Millisecond pulsars represent an evolutionarily distinct group among rotation-powered pulsars. Outside the radio band, the soft X-ray range (similar to 0.1-10 keV) is most suitable for studying radiative mechanisms operating in these fascinating objects. X-ray observations revealed diverse properties of emission from millisecond pulsars. For the most of them, the bulk of radiation is of a thermal origin, emitted from small spots ( polar caps) on the neutron star surface heated by relativistic particles produced in pulsar acceleration zones. On the other hand, a few other very fast rotating pulsars exhibit almost pure nonthermal emission generated, most probably, in pulsar magnetospheres. There are also examples of nonthermal emission detected from X-ray nebulae powered by millisecond pulsars, as well as from pulsar winds shocked in binary systems with millisecond pulsars as companions. These and other most important results obtained from X-ray observations of millisecond pulsars are reviewed in this paper, as well as results from the search for millisecond pulsations in X-ray flux of the radio-quite neutron star RX J1856.5-3754. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35805 USA. RP Zavlin, VE (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Lab, SD50, Huntsville, AL 35805 USA. EM vyacheslav.zavlin@msfc.nasa.gov NR 62 TC 30 Z9 30 U1 0 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD APR PY 2007 VL 308 IS 1-4 BP 297 EP 307 DI 10.1007/s10509-007-9297-y PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 166BC UT WOS:000246351000038 ER PT J AU Livingstone, MA Kaspi, VM Gavriil, FP Manchester, RN Gotthelf, EVG Kuiper, L AF Livingstone, Margaret A. Kaspi, Victoria M. Gavriil, Fotis P. Manchester, Richard N. Gotthelf, E. V. G. Kuiper, Lucien TI New phase-coherent measurements of pulsar braking indices SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article DE pulsars; timing ID HIGH-MAGNETIC-FIELD; SPIN-DOWN; RADIO PULSARS; PSR B0540-69; YOUNG; MAGNETOSPHERE; PSR-B1509-58; EVOLUTION; ROTATOR; HISTORY AB Pulsar braking indices offer insight into the physics that underlies pulsar spin-down. Only five braking indices have been measured via phase-coherent timing; all measured values are less than 3, the value expected from magnetic dipole radiation. Here we present new measurements for three of the five pulsar braking indices, obtained with phase-coherent timing for PSRs J18460258 (n = 2.65 +/- 0.01), B1509-58 ( n = 2.839 +/- 0.001) and B0540-69 ( n = 2.140 +/- 0.009). We discuss the implications of these results and possible physical explanations for them. C1 McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada. NASA, Goddard Space Flight Ctr Code 662, Xray Astrophys Lab, Greenbelt, MD 20771 USA. CSIRO, Australia Telescope Natl Facil, Epping, NSW 1710, Australia. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Netherlands Inst Space Res, NL-3584 CA Utrecht, Netherlands. RP Livingstone, MA (reprint author), McGill Univ, Dept Phys, 3600 Univ St,Rutherford Phys Bldg, Montreal, PQ H3A 2T8, Canada. EM maggie@physics.mcgill.ca NR 31 TC 51 Z9 52 U1 0 U2 4 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD APR PY 2007 VL 308 IS 1-4 BP 317 EP 323 DI 10.1007/s10509-007-9320-3 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 166BC UT WOS:000246351000040 ER PT J AU Dib, R Kaspi, VM Gavriil, FP AF Dib, Rim Kaspi, Victoria M. Gavriil, Fotis P. TI 10 years of RXTE monitoring of anomalous X-ray pulsar 4U 0142+61: long-term variability SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article DE pulsars : individual (4U 0142+61); stars : neutron; X-rays : stars ID EMISSION AB We report on 10 yr of monitoring of the 8.7-s Anomalous X-ray Pulsar 4U 0142+ 61 using the Rossi X-Ray Timing Explorer (RXTE). This pulsar exhibited stable rotation from 2000 until February 2006: the RMS phase residual for a spin-down model which includes v, empty set, and empty set. is 2.3%. We report a possible phase-coherent timing solution valid over a 10-yr span extending back to March 1996. A glitch may have occurred between 1998 and 2000, but it is not required by the existing data. We also report that the source's pulse profile has been evolving in the past 6 years, such that the dip of emission between its two peaks has been getting shallower since 2000, almost as if the profile is recovering to its pre-2000 morphology, in which there was no clear distinction between the peaks. These profile variations are seen in the 2-4 keV band but not in 6-8 keV. Finally, we present the pulsed flux time series of the source in 2-10 keV. There is evidence of a slow but steady increase in the source's pulsed flux since 2000. The pulsed flux variability and the narrow-band pulse profile changes present interesting challenges to aspects of the magnetar model. C1 McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada. NASA, Goddard Space Flight Ctr, Xray Astrophys Lab, Greenbelt, MD 20771 USA. RP Dib, R (reprint author), McGill Univ, Dept Phys, 3600 Univ St, Montreal, PQ H3A 2T8, Canada. EM rim@physics.mcgill.ca; vkaspi@physics.mcgill.ca; gavriil@milkyway.gsfc.nasa.gov NR 12 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD APR PY 2007 VL 308 IS 1-4 BP 487 EP 491 DI 10.1007/s10509-007-9313-2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 166BC UT WOS:000246351000063 ER PT J AU Ibrahim, AI Anwer, H Soliman, MH Mackie-Jones, N Dhuga, KS Parke, WC Swank, JH Ukwatta, T Hussein, MT El-Sherbini, T AF Ibrahim, Alaa I. Anwer, Hisham Soliman, Mohamed H. Mackie-Jones, Nicholas Dhuga, Kalvir S. Parke, William C. Swank, Jean H. Ukwatta, Tilan Hussein, M. T. El-Sherbini, T. TI On the iron interpretation of the 6.4 keV emission line from SGR 1900+14 SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article DE gamma-rays : observations; X-rays : observations; pulsars : individual SGR 1900+14; pulsars : general ID CYCLOTRON-RESONANCE; GAMMA; SGR-1806-20; DISCOVERY; BURST AB A 6.4 keV emission line was discovered in an unusual burst from the soft gamma repeater SGR 1900+14 with the Rossi X-ray Timing Explorer (RXTE). The line was detected in part of a complex multipeak precursor that preceded the unusual burst of 1998 August 29, i.e. two days after the giant flare of August 27 from the source. The origin of the line was not firmly identified and two possible interpretations were equally plausible including (a) K alpha fluorescence from a small iron rich material that was ejected to the magnetosphere during the August 27 flare, and (b) proton or alpha-particle cyclotron resonance. If the iron scenario was correct, we expect to find evidence for the line during the intervening interval between the flare and the August 29 burst, i.e. on August 28. Here we present the results of the August 28 burst observation, taken with RXTE. We detect a total of seven bursts whose individual and joint spectra do not show evidence for spectral lines. We also investigated a sample of nine bursts before and after the August 29 burst (from 1998 June to December) that do not reveal evidence for a spectral line near 6.4 keV or elsewhere. These results disfavor the iron scenario and make the proton/alpha-particle cyclotron resonance interpretation more plausible. The appearance of the emission line in part of a complex burst and its absence from the studied sample indicate that the line is likely due to a transient phenomenon that may depend on the burst morphology, energetics and the properties of the emission region. C1 Cairo Univ, Fac Sci, Dept Phys, Cairo, Egypt. Cairo Univ, Fac Sci, Ctr Adv Interdisciplinary Sci, Div Astrophys, Cairo, Egypt. George Washington Univ, Dept Phys, Washington, DC 20052 USA. NASA, Goddard Space Flight Ctr, Astrophys Sci Div, Greenbelt, MD 20771 USA. RP Ibrahim, AI (reprint author), Cairo Univ, Fac Sci, Dept Phys, Cairo, Egypt. EM alaa@gwu.edu RI Ibrahim, Alaa/A-6250-2008; Swank, Jean/F-2693-2012 OI Ibrahim, Alaa/0000-0002-8791-7270; NR 10 TC 0 Z9 0 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD APR PY 2007 VL 308 IS 1-4 BP 535 EP 539 DI 10.1007/s10509-007-9345-7 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 166BC UT WOS:000246351000071 ER PT J AU Watts, AL Strohmayer, TE AF Watts, Anna L. Strohmayer, Tod E. TI High frequency oscillations during magnetar flares SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article DE magnetars; neutron stars; seismology ID SOFT GAMMA-REPEATERS; X-RAY OSCILLATIONS; NEUTRON-STARS; GIANT-FLARE; TORSIONAL OSCILLATIONS; RADIATIVE MECHANISM; 2004 HYPERFLARE; SGR 1806-20; SGR-1806-20; DISCOVERY AB The recent discovery of high frequency oscillations during giant flares from the Soft Gamma Repeaters SGR 1806-20 and SGR 1900+14 may be the first direct detection of vibrations in a neutron star crust. If this interpretation is correct it offers a novel means of testing the neutron star equation of state, crustal breaking strain, and magnetic field configuration. We review the observational data on the magnetar oscillations, including new timing analysis of the SGR 1806-20 giant flare using data from the Ramaty High Energy Solar Spectroscopic Imager and the Rossi X-ray Timing Explorer. We discuss the implications for the study of neutron star structure and crust thickness, and outline areas for future investigation. C1 Max Planck Inst Astrophys, D-85741 Garching, Germany. NASA, Goddard Space Flight Ctr, Explorat Universe Div, Greenbelt, MD 20771 USA. RP Watts, AL (reprint author), Max Planck Inst Astrophys, Karl Schwarzchild Str 1, D-85741 Garching, Germany. EM anna@mpa-garching.mpg.de NR 23 TC 17 Z9 17 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD APR PY 2007 VL 308 IS 1-4 BP 625 EP 629 DI 10.1007/s10509-007-9296-z PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 166BC UT WOS:000246351000087 ER PT J AU Luo, C Zender, CS Bian, HS Metzger, S AF Luo, Chao Zender, Charles S. Bian, Huisheng Metzger, Swen TI Role of ammonia chemistry and coarse mode aerosols in global climatological inorganic aerosol distributions SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE aerosol thermodynamics; gas/aerosol partitioning; ammonia chemistry; global chemical transport model; inorganic aerosol compositions ID GENERAL-CIRCULATION MODEL; CHEMICAL-TRANSPORT MODEL; 3-DIMENSIONAL MODEL; THERMODYNAMIC MODEL; MINERAL AEROSOL; TROPOSPHERIC CHEMISTRY; ATMOSPHERIC TRANSPORT; OPTICAL-THICKNESS; EQUILIBRIUM-MODEL; OZONE AB We use an inorganic aerosol thermodynamic equilibrium model in a three-dimensional chemical transport model to understand the roles of ammonia chemistry and natural aerosols on the global distribution of aerosols. The thermodynamic equilibrium model partitions gas-phase precursors among modeled aerosol species self-consistently with ambient relative humidity and natural and anthropogenic aerosol emissions during the 1990s. Model simulations show that accounting for aerosol inorganic thermodynamic equilibrium, ammonia chemistry and dust and sea-salt aerosols improve agreement with observed SO4, NO3, and NH4 aerosols especially at North American sites. This study shows that the presence of sea salt, dust aerosol and ammonia chemistry significantly increases sulfate over polluted continental regions. In all regions and seasons, representation of ammonia chemistry is required to obtain reasonable agreement between modeled and observed sulfate and nitrate concentrations. Observed and modeled correlations of sulfate and nitrate with ammonium confirm that the sulfate and nitrate are strongly coupled with ammonium. SO4 concentrations over East China peak in winter, while North American SO4 peaks in summer. Seasonal variations of NO3 and SO4 are the same in East China. In North America, the seasonal variation is much stronger for NO3 than SO4 and peaks in winter. Natural sea salt and dust aerosol significantly alter the regional distributions of other aerosols in three main ways. First, they increase sulfate formation by 10-70% in polluted areas. Second, they increase modeled nitrate over oceans and reduce nitrate over Northern hemisphere continents. Third, they reduce ammonium formation over oceans and increase ammonium over Northern Hemisphere continents. Comparisons of SO4, NO3 and NH4 deposition between pre-industrial, present, and year 2100 scenarios show that the present NO3 and NH4 deposition are twice pre-industrial deposition and present SO4 deposition is almost five times pre-industrial deposition. (c) 2006 Elsevier Ltd. All rights reserved. C1 Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. Max Planck Inst Chem, D-55128 Mainz, Germany. RP Luo, C (reprint author), Univ Calif Irvine, Dept Earth Syst Sci, 1101E Croul Hall, Irvine, CA 92697 USA. EM cluo@uci.edu RI Zender, Charles/D-4485-2012 OI Zender, Charles/0000-0003-0129-8024 NR 74 TC 21 Z9 22 U1 1 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 EI 1873-2844 J9 ATMOS ENVIRON JI Atmos. Environ. PD APR PY 2007 VL 41 IS 12 BP 2510 EP 2533 DI 10.1016/j.atmosenv.2006.11.030 PG 24 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 163DY UT WOS:000246140200003 ER PT J AU Barr, YR Bacal, K Jones, JA Hamilton, DR AF Barr, Yael R. Bacal, Kira Jones, Jeffrey A. Hamilton, Douglas R. TI Breast cancer and spaceflight: Risk and management SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Review DE fine needle aspiration; FNA; spaceflight; radiation ID AIRLINE CABIN ATTENDANTS; DEPOT-MEDROXYPROGESTERONE ACETATE; RANDOMIZED CONTROLLED TRIALS; RESIDENTIAL MAGNETIC-FIELDS; FEMALE FLIGHT ATTENDANTS; EPSTEIN-BARR-VIRUS; SPACE-FLIGHT; AROMATASE INHIBITORS; POSTMENOPAUSAL WOMEN; POOLED ANALYSIS AB Spaceflight exposes astronauts to a host of environmental factors which could increase their risk for cancer. Epidemiological studies have shown an increased incidence of breast cancer in female commercial flight attendants, with occupational risk factors as one of the proposed mechanisms for the higher incidence in this cohort. Since female astronauts are exposed to similar occupational conditions as flight attendants, they too may be at an increased risk for breast cancer. With the planning of exploration class missions to the Moon and to Mars it is important to assess and minimize the risk for breast malignancy, and to have a well-defined protocol for the diagnosis and treatment of a breast mass discovered during a mission. Risk factors for development of breast cancer in the female astronaut include ionizing radiation, disrupted melatonin homeostasis secondary to circadian shifting, chemical exposure, and changes in immune function. Preflight, in-flight, and postflight screening and management modalities include imaging and fine needle aspiration (FNA). Employing such a strategy may provide a viable management approach in the case of a newly diagnosed breast mass inflight. C1 Univ Texas, Med Branch, Dept Prevent Med & Community Hlth, Div Aerosp Med, Galveston, TX 77555 USA. Ohio Univ, Dept Family Med, Div Emergency Med, Coll Osteopath Med, Athens, OH 45701 USA. Ohio Univ, Voinovich Ctr Leadership & Publ Affairs, Athens, OH 45701 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Barr, YR (reprint author), Univ Texas, Med Branch, Dept Prevent Med & Community Hlth, Div Aerosp Med, Galveston, TX 77555 USA. EM yrbarr@utmb.edu NR 113 TC 9 Z9 9 U1 1 U2 10 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD APR PY 2007 VL 78 IS 4 SU S BP A26 EP A37 PG 12 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 157TU UT WOS:000245744700006 PM 17511296 ER PT J AU Jones, JA Mccarten, M Manuel, K Djojonegoro, B Murray, J Feiversen, A Wear, M AF Jones, Jeffrey A. Mccarten, Michael Manuel, Keith Djojonegoro, Baby Murray, Jocelyn Feiversen, Al Wear, Mary TI Cataract formation mechanisms and risk in aviation and space crews SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Review DE cataracts; spaceflight; aviator; oxidative damage; ionizing radiation; occupational exposure ID ACCELERATED HEAVY-PARTICLES; RADIATION-INDUCED CATARACT; LENS EPITHELIAL-CELLS; POSTERIOR SUBCAPSULAR CATARACTS; AGE-RELATED CATARACT; ULTRAVIOLET-RADIATION; VITAMIN-E; INFRARED RADIATION; RAT LENS; UV-B AB Induction of cataracts by occupational exposure in flight crew has been an important topic of interest in aerospace medicine over the past 5 yr, in association with numerous reports of flight-associated disease incidences. Due to numerous confounding variables, it has been difficult to determine whether there is increased cataract risk directly caused by interaction with the flight environment, specifically associated with added radiation exposure during flight. Military aviator records from the U.S. Air Force (USAF) and U.S. Navy (USN) and U.S. astronauts at NASA's Lyndon B. Johnson Space Center were evaluated for the presence, location, and age of diagnosis of cataracts. Military aviators with cataracts were found to have a younger average age at onset of their cataracts compared with astronauts with cataracts, however the prevalence of cataracts was found to be higher in astronauts than in military aviators. U.S. Air Force and U.S. Navy aviators' cataracts were most commonly located in the posterior subcapsular region of the lens while astronauts' cataracts were most likely to originate in the cortical zone. A prospective clinical trial which controls for confounding variables in examination technique, cataract classification, diet, exposure, and pharmacological intervention is needed to determine what percentage of the risk for cataracts is due to radiation, and how to best develop countermeasures to protect flight crews from radiation bioeffects in the future. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. USN Acad, Med Corps, Houston, TX USA. Kelsey Seybold Clin, Houston, TX USA. Wyle Labs, Houston, TX USA. RP Jones, JA (reprint author), SD Space Med & Hlth Care Syst, 2101 NASA Pkwy, Houston, TX 77030 USA. EM Jeffrey.a.jones@nasa.gov NR 155 TC 25 Z9 30 U1 2 U2 9 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD APR PY 2007 VL 78 IS 4 SU S BP A56 EP A66 PG 11 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 157TU UT WOS:000245744700010 PM 17511300 ER PT J AU Jones, JA Riggs, PK Yang, TC Pedemonte, CH Clarke, MSF Feeback, DL Au, WW AF Jones, Jeffrey A. Riggs, Penny K. Yang, Tracy C. Pedemonte, Carlos H. Clarke, Mark S. F. Feeback, Daniel L. Au, William W. TI Ionizing radiation-induced bioeffects in space and strategies to reduce cellular injury and carcinogenesis SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE space radiation; bioeffects; cancer; FISH; radioprotectants; chemoprevention; lipid peroxidation; membrane resistance ID CELLS AB Background: The bioeffects of space radiation on organisms outside of the environment of Earth's magnetosphere are a concern for long-duration exploration spaceflights. Potential mutagenic effects from space radiation exposure result from direct DNA damage or indirectly from the production of reactive oxygen species (ROS). Hypotheses: 1) Transepithelial electrical resistance (TER) measurements in cell culture monolayers may be used as a model system for detecting cell damage produced by exposure to simulated space radiation and for testing potential chemoprotective agents 2) biomarkers of exposure that quantitate indirect radiation effects may allow prediction of cellular DNA damage; and 3) a multiple agent, chemoprevention cocktail may reduce the bioeffects of simulated space radiation. Methods: Normal human and canine lung, breast, and renal epithelial cells were assayed in vitro and exposed to escalating doses of gamma or heavy-ion carbon (290 MeV/u), ceon (400, MeV/u), or iron (600 MeV/u) irradiation. Post-exposure measurement; of TER, lipid peroxidation (LP) via measurement of 4-hydroxy-nonenal (4-HNE), and malonaldehyde (MDA) and assessment of chromosome damage via fluorescence in situ hybridization with tandem labeling of chromosome I were performed. Results: Cells exposed to intermediate or high doses of radiation (5, 10, and 25 Gy) showed characteristic diminution in TER, thought to be secondary to dysfunction of tight junctions, and associated with membrane LP and other mechanisms, The cells also showed increases in 4-HNE + MDA measurements and increased frequency of chromosomal aberrations. Preliminary studies of cells incubated with media containing a combination of chemoprotective agents at the time of radiation exposure showed a 15-50% reduction in the radiation-induced changes in membrane resistance, levels of LP, and chromosomal aberrations relative to their unprotected cellular counterparts. Conclusion: TER measurement, in conjunction with measures of LP, may provide a useful model for determination of physiological changes caused by radiation exposure and the efficacy of chemoprotective agents. A multi-agent mixture of chemoprotective agents may be more effective than previously evaluated single agents alone. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Houston, Coll Pharm, Houston, TX 77030 USA. Inst Space Syst Operat, Houston, TX 77030 USA. Univ Space Res Assoc, Div Space Life Sci, Houston, TX USA. Univ Texas, Med Branch, Dept Prevent Med & Community Hlth, Galveston, TX 77555 USA. RP Jones, JA (reprint author), NASA, Lyndon B Johnson Space Ctr, SD 26,Flight Med Bldg 8,2101 NASA Rd 1, Houston, TX 77058 USA. EM jajones@ems.jsc.nasa.gov RI Riggs, Penny/A-8192-2008 OI Riggs, Penny/0000-0003-3296-320X NR 29 TC 11 Z9 13 U1 0 U2 4 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD APR PY 2007 VL 78 IS 4 SU S BP A67 EP A78 PG 12 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 157TU UT WOS:000245744700011 PM 17511301 ER PT J AU Kirkpatrick, AW Jones, JA Sargsyan, A Hamilton, DR Melton, S Beck, G Nicolau, S Campbell, M Dulchavsky, S AF Kirkpatrick, Andrew W. Jones, Jeffrey A. Sargsyan, Ashot Hamilton, Douglas R. Melton, Shannon Beck, George Nicolau, Savvas Campbell, Mark Dulchavsky, Scott TI Trauma sonography for use in microgravity SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE microgravity; sonography; abdominal injury; thoracic injury; human spaceflight; International Space Station ID BLUNT ABDOMINAL-TRAUMA; INTERNATIONAL-SPACE-STATION; CLINICAL ULTRASOUND ABOARD; FATALLY INJURED PATIENTS; FOCUSED ASSESSMENT; THORACIC ULTRASOUND; ENDOSCOPIC SURGERY; PNEUMOTHORAX; CARE; ULTRASONOGRAPHY AB Sonography is the only medical imaging modality aboard the ISS, and is likely to remain the leading imaging modality in future human spaceflight programs. While trauma sonography (TS) has been well recognized for terrestrial trauma settings, the technique had to be evaluated for suitability in spaceflight prior to adopting it as an operational capability. The authors found the following four-phased evaluative approach applicable to this task: I) identifying standard or novel terrestrial techniques for potential use in space medicine; 2) developing and testing these techniques with suggested modifications on the ground (I G) either in clinical settings or in animal models, as appropriate; 3) evaluating and refining the techniques in parabolic flight (0 G); and 4) validating and implementing for clinical use in space. In Phase I of the TS project, expert opinion and literature review suggested TS to be a potential screening tool for trauma in space. In Phase II, animal models were developed and tested in ground studies, and clinical studies were carried out in collaborating trauma centers. In Phase III, animal models were flight-tested in the NASA KC-135 Reduced Gravity Laboratory. Preliminary results of the first three phases demonstrated the potential clinical utility of TS in microgravity. Phase IV studies have begun to address crew training issues, onboard imaging protocols, and data transfer procedures necessary to offer the modified TS technique for space use. C1 Foothills Med Ctr Calgary, Calgary, AB T2N 2T9, Canada. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Wyle Labs Inc, Houston, TX USA. Vancouver Hosp & Hlth Sci Ctr, Vancouver, BC V5Z 1M9, Canada. McCaiston Med Ctr, Paris, TX USA. Henry Ford Med Ctr, Detroit, MI USA. RP Kirkpatrick, AW (reprint author), Foothills Med Ctr Calgary, Calgary, AB T2N 2T9, Canada. NR 53 TC 10 Z9 10 U1 1 U2 1 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD APR PY 2007 VL 78 IS 4 SU S BP A38 EP A42 PG 5 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 157TU UT WOS:000245744700007 PM 17511297 ER PT J AU Larios-Sanz, M Kourentzi, KD Warmflash, D Jones, J Pierson, DL Willson, RC Fox, GE AF Larios-Sanz, Maia Kourentzi, Katerina D. Warmflash, David Jones, Jeffrey Pierson, Duane L. Willson, Richard C. Fox, George E. TI 16S rRNA beacons for bacterial monitoring during human space missions SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE spacecraft; bacteria; monitoring; 16S rRNA ID FLIGHT; OLIGONUCLEOTIDES; MICROGRAVITY; SPACEFLIGHT; PROBES AB Microorganisms, are unavoidable in space environments and their presence has, at times, been a Source of problems. Concerns about disease during human space missions are particularly important considering the significant changes the immune system incurs during spaceflight and the history of microbial contamination aboard the Mir space station. Additionally, these contaminants may have adverse effects on instrumentation and life-support systems. A sensitive, highly specific system to detect, characterize, and monitor these microbial populations is essential. Here n we describe a monitoring approach that uses I SS rRNA targeted molecular beacons to successfully detect several specific bacterial groupings. This methodology will greatly simplify in-flight monitoring by minimizing sample handling and processing. We also address and prov de Solutions to target accessibility problems encountered in hybridizations that target 16S rRNA. C1 Univ Houston, Dept Biol & Biochem, Houston, TX 77204 USA. Univ Houston, Dept Chem Engn, Houston, TX 77204 USA. Univ Space Res Assoc, Houston, TX USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Larios-Sanz, M (reprint author), Univ Houston, Dept Biol & Biochem, Houston, TX 77204 USA. EM maialarios@yahoo.com NR 25 TC 3 Z9 3 U1 2 U2 3 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD APR PY 2007 VL 78 IS 4 SU S BP A43 EP A47 PG 5 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 157TU UT WOS:000245744700008 PM 17511298 ER PT J AU Pietrzyk, RA Jones, JA Sams, CF Whitson, PA AF Pietrzyk, Robert A. Jones, Jeffrey A. Sams, Clarence F. Whitson, Pegcy A. TI Renal stone formation among astronauts SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE kidney stone; calculi; microgravity; space medicine ID SPACE-FLIGHT; RISK AB Introduction: With the continued construction of the International Space Station, humans are living longer in the microgravity environment of space. However, many questions still exist as to the physiological effects of spaceflight on the human body. Bone loss, cardiovascular changes, and muscle atrophy are well-documented health risks to humans during spaceflight. Another potential serious health complication is the development of renal stones. The development of a renal stone may not only impact the health of the crewmember, but also the success of the mission. Methods: A retrospective analysis of astronaut data from 24-h urine samples collected prior to launch and immediately after landing was performed. Urine characteristics associated with renal stone formation were analyzed and the relative injury supersaturations of stone-forming constituents calculated. Results. In the current study previously collected data to identify urinary factors associated with renal stone formation demonstrated an, increased risk in astronauts who had actually formed a renal stone. Increased urinary supersaturation of the stone-forming salts was observed in those astronauts who formed renal stones. Similar changes in urinary supersaturation were noted among many astronauts after landing, indicating an increased postflight risk for stone formation. Conclusions: An assessment program should be undertaken to identify aid evaluate astronauts with elevated risk factors prior to flight and immediately following landing. Individualized recommendations can be prescribed to astronauts and may include dietary changes, increased fluid intake, or medications to minimize the risk of stone formation. C1 NASA, Lyndon B Johnson Space Ctr, Space Med & Crew Hlth Care Syst, Houston, TX 77058 USA. Wyle Labs, Houston, TX USA. RP Pietrzyk, RA (reprint author), NASA, Lyndon B Johnson Space Ctr, Space Med & Crew Hlth Care Syst, Mail Code SD2, Houston, TX 77058 USA. EM jeffrey.a.jones@jsc.nasa.gov NR 14 TC 27 Z9 29 U1 0 U2 1 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD APR PY 2007 VL 78 IS 4 SU S BP A9 EP A13 PG 5 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 157TU UT WOS:000245744700004 PM 17511294 ER PT J AU Pisacane, VL Kuznetz, LH Locan, JS Clark, JB Wissler, EH AF Pisacane, Vincent L. Kuznetz, Lawrence H. Locan, James S. Clark, Johnathan B. Wissler, Eugene H. TI Thermoregulatory models of space shuttle and space station activities SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE space physiology; thermoregulation; modeling; Shuttle Space Station; astronauts; ACES ID COOLING GARMENT; SUIT AB Background: Thermoregulation is critical for survival in space, especially during contingencies demanding of human cognitive and physical performance. A review of the negative feedback human thermoregulatory system is provided. The Advanced Crew Escape Suit is worn by astronauts during ascent and descent on the Space Shuttle to provide active cooling for nominal and contingency operations and protection from loss of cabin pressure mishaps. Failure of a thermal system control element during a recent Shuttle flight resulted in a single point failure that could have elevated cabin temperature, possibly resulting in cognitive deficits of the pilot during the reentry and landing phases. Methods: The efficacy of the existing cooling equipment and procedures for maintaining crew thermal comfort in the event of such a failure was assessed. The Wissler and 41-node thermoregulatory models were used to conduct a parametric study of Shuttle cabin temperatures and resulting thermal effects on crew. Results: Under high metabolic loads, crew-member core temperatures and heat storage are shown to increase beyond allowable limits using this analysis. Resulting levels of thermal stress may exceed standardized limits, after which cognitive performance and manual tracking ability are diminished. Discussion: The operational procedure for entry and landing during this failure scenario may result in significant thermal compromise to crewmembers, including cognitive and manual performance deficits. Revision of the flight rule governing crew actions during compromise of cabin thermal control has been undertaken to minimize thermal stress on returning Shuttle crewmembers. Modifications to the crew thermal protection system for the Shuttle are suggested. C1 Univ Space Res Assoc, NASA, JSC, Houston, TX USA. USN Acad, Annapolis, MD 21402 USA. NASA, Lyndon B Johnson Space Ctr, Occupat Med Branch, Houston, TX 77058 USA. Baylor Coll Med, Natl Space Biomed Res Inst, Houston, TX 77030 USA. Univ Texas, Austin, TX 78712 USA. RP Kuznetz, LH (reprint author), Univ Space Res Assoc, NASA, JSC, Houston, TX USA. EM pisacane@usna.edu; lawrence.h.kuznetz@nasa.gov NR 14 TC 6 Z9 6 U1 1 U2 8 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD APR PY 2007 VL 78 IS 4 SU S BP A48 EP A55 PG 8 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 157TU UT WOS:000245744700009 PM 17511299 ER PT J AU Pool, SL Davis, JR AF Pool, Sam Lee Davis, Jeffrey R. TI Space medicine roots: A historical perspective for the current direction SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Editorial Material C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Pool, SL (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD APR PY 2007 VL 78 IS 4 SU S BP A3 EP A4 PG 2 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 157TU UT WOS:000245744700002 PM 17511292 ER PT J AU Stepaniak, PC Hamilton, GC Olson, JE Gilmore, SM Stizza, DM Beck, B AF Stepaniak, Philip C. Hamilton, Glenn C. Olson, James E. Gilmore, Stevan M. Stizza, Denis M. Beck, Bradley TI Physiologic effects of simulated plus Gx orbital reentry in primate models of hemorrhagic shock SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE space medicine; hemorrhagic shock; centrifugation; acceleration; spaceflight ID PULMONARY BLOOD FLOW; TRANSVERSE GX; SPACE-FLIGHT; CARDIAC ARRHYTHMIAS; ACCELERATION; TOLERANCE; THERMODILUTION; RESUSCITATION; HEMODYNAMICS; EXPOSURE AB Introduction: While the physiologic effects of space travel are documented in healthy individuals, little is known about its impact on medically ill or injured persons. In this study, hemorrhagic shock in primates was used to model a potentially common pathophysiologic condition during exposure to gravitational forces simulating return from Earth orbit. This experiment did not model the effects of cardiovascular deconditioning that normally occur during spaceflight. Methods: Using invasive hemodynamic monitoring, serial cardiovascular and laboratory parameters in baboons (Papio papio) were studied. Subjects were centrifuged at either a low +Gx (3.3 G maximum) or high +Gx (7.8 G maximum) acceleration reentry profile before and after being subjected to either class 11 (20% volume loss) or class IV (40% volume loss) hemorrhagic shock. Results: Significant alterations in cardiovascular and laboratory parameters occurred during shock and exposure to high and low +Gx acceleration. Shock classification was the primary determinant of change in cardiovascular function. During the experimental protocol, 31 of 32 animals survived (97% survival). After a 1-wk post-protocol observation period, 28 of 32 subjects survived (88% survival). Conclusions: This preliminary study presents data that suggest that the emergent return of a medically compromised individual without resuscitation may be potentially survivable. However, medical stabilization with volume resuscitation, supplemental oxygen, and noninvasive monitoring would likely optimize clinical outcomes in the event of significant hemorrhagic shock states necessitating emergent deorbit. C1 Wright State Univ, Dept Emergency Med, Kettering, OH USA. Wright State Univ, Dept Physiol & Biophys, Dayton, OH 45435 USA. Wright State Univ, Dept Aerosp Med, Dayton, OH 45435 USA. RP Stepaniak, PC (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code SD2,2101 NASA Pkwy, Houston, TX 77058 USA. EM philip.stepaniak-1@nasa.gov NR 50 TC 3 Z9 3 U1 0 U2 0 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD APR PY 2007 VL 78 IS 4 SU S BP A14 EP A25 PG 12 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 157TU UT WOS:000245744700005 PM 17511295 ER PT J AU Stepaniak, PC Ramchandani, SR Jones, JA AF Stepaniak, Philip C. Ramchandani, Suneil R. Jones, Jeffrey A. TI Acute urinary retention among astronauts SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article ID NEUROGENIC BLADDER; WOMEN; COMPLICATIONS; MANAGEMENT AB Although acute urinary retention (AUR) is not commonly thought of as a life-threatening condition, its presentation in orbit can lead to a number of medical complications that could compromise a space mission. We report on a middle-aged astronaut who developed urinary retention during two spaceflights. On the first mission of note, the astronaut initially took standard doses of promethazine and scopolamine before launch, and developed AUR immediately after entering orbit. For the first 3 cl, the astronaut underwent intermittent catheterizations with a single balloon-tipped catheter. Due to the lack of iodine solution on board and the need for the astronaut to complete certain duties without interruption, the catheter was left in place for a total of 4 d. Although the ability to void returned after day 7, a bout of AUR reemerged on day 10, 1 d before landing. On return to Earth, a cystometrogram was unremarkable. During the astronaut's next mission, AUR again recurred for the first 24 h of microgravity exposure, and the astronaut was subsequently able to void spontaneously while in space. This report details the presentation of this astronaut, the precautions that were taken for space travel subsequent to the initial episode of AUR, and the possible reasons why space travel can predispose astronauts to urinary retention while in orbit. The four major causes of AUR-obstructive, pharmacologic, psychogenic, and neurogenic-are discussed, with an emphasis on how these may have played a role in this case. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Stepaniak, PC (reprint author), NASA, Lyndon B Johnson Space Ctr, Med Operat SD2,2101 NASA Pkwy, Houston, TX 77058 USA. EM philip.stepaniak-1@nasa.gov NR 18 TC 5 Z9 5 U1 0 U2 1 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD APR PY 2007 VL 78 IS 4 SU S BP A5 EP A8 PG 4 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 157TU UT WOS:000245744700003 PM 17511293 ER PT J AU Warmflash, D Larios-Sanz, M Jones, J Fox, GE Mckay, DS AF Warmflash, David Larios-Sanz, Maia Jones, Jeffrey Fox, George E. McKay, David S. TI Biohazard potential of putative Martian organisms during missions to Mars SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE Mars; biosafety; native microorganisms; human missions ID METEORITE ALH84001; LABELED RELEASE; SURFACE-CHEMISTRY; VIKING MISSION; SOIL ANALOGS; LIFE; WATER; MODEL; ATMOSPHERE; SEARCH AB Exploration Class missions to Mars will require precautions against potential contamination by any native microorganisms that may be incidentally pathogenic to humans. While the results of NASA's Viking biology experiments of the 1970s have been generally interpreted as inconclusive for surface organisms, and attributed to active but nonbiological chemistries, the possibility of native surface life has never been ruled out completely. It is possible that, prior to the first human landing on Mars, robotic craft and sample return missions will provide enough data to know with certainty whether future human landing sites harbor extant life forms. If native life were found to exist, it would be problematic to determine whether any of its species might present a medical danger to astronauts. Therefore, it will become necessary to assess empirically the risk that the planet contains pathogens based on terrestrial examples of pathogenicity and to take a reasonably Cautious approach to biohazard protection. A survey of terrestrial pathogens was conducted with special emphasis on those whose evolution has not depended on the presence of animal hosts. The history of the development and implementation of Apollo anti-contamination protocol and recommendations of the National Research Council's Space Studies Board regarding Mars were reviewed. Organisms can emerge in Nature in the absence of indigenous animal hosts and both infectious and non-infectious human pathogens are therefore theoretically possible on Mars. Although remote, the prospect of Martian surface life, together with the existence of a diversity of routes by which pathogenicity has emerged on Earth, suggests that the probability of human pathogens on Mars, while low, is not zero. Still, since the discovery and study of Martian life can have long-term benefits for humanity, the risk that Martian life might include pathogens should not be an obstacle to human exploration. As a precaution, it is recommended that EVA (extravehicular activity) suits be decontaminated when astronauts enter surface habitats upon returning from field activity and that biosafety protocols approximating laboratory BSL 2 be developed for astronauts working in laboratories on the Martian surface. Quarantine of astronauts and Martian materials arriving on Earth should also be part of a human mission to Mars, and this and the surface biosafety program should be integral to human expeditions from the earliest stages of the mission planning. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Space Res Assoc, Houston, TX USA. Univ Houston, Dept Biol & Biochem, Houston, TX USA. RP Warmflash, D (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code SD,Bldg 29, Houston, TX 77058 USA. EM dwamafla@ems.jsc.nasa.gov NR 80 TC 1 Z9 1 U1 2 U2 5 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 EI 1943-4448 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD APR PY 2007 VL 78 IS 4 SU S BP A79 EP A88 PG 10 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 157TU UT WOS:000245744700012 PM 17511302 ER PT J AU Linteris, GT Takahashi, F Katta, VR AF Linteris, Gregory T. Takahashi, Fumiaki Katta, Viswanath R. TI Cup-burner flame extinguishment by CF3Br and Br-2 SO COMBUSTION AND FLAME LA English DT Article DE fire suppression; cup burner; Halon replacement; flame extinction; CF3Br ID JET DIFFUSION FLAMES; REACTION KERNEL STRUCTURE; METHANE FLAMES; CHEMICAL INHIBITION; NONPREMIXED FLAMES; FIRE SUPPRESSANTS; METHYL BROMIDE; AIR FLAMES; HYDROGEN; MICROGRAVITY AB Experiments and calculations have been performed for a methane-air coflow diffusion flame, in the cup-burner configuration, with CF3Br or Br-2 added to the air stream. The time-dependent, two-dimensional numerical code, which includes a detailed kinetic model and diffusive transport, has predicted the flame extinction within 4 or 8% for each. Analysis of the flame structure has allowed the mechanisms of flame weakening in the base and trailing flame regions to be compared. The agents CF3Br and Br2 behave very similarly with regard to flame extinguishment: both raise the temperature in the flame everywhere, as well as lower radical volume fractions in the trailing diffusion flame and at the peak reactivity spot (the "reaction kernel") at the flame base where the flame is stabilized. The mechanism of lowered radical volume fractions is shown primarily to be due to a catalytic cycle involving bromine species in both regions of the flame, with small contributions from radical trapping by fluorinated species in the trailing diffusion flame. In the reaction kernel, the radical volume fractions are reduced more, and the catalytic radical recombination cycles are shown to be more effective as compared to in the trailing diffusion flame. At the latter location, the effectiveness of the agents is reduced because the hydrocarbon species, which are necessary for the regeneration of HBr, are scarce at the location of the peak radical volume fraction (i.e., at the flame zone), a limitation which does not exist in the reaction kernel, where there is good upstream mixing of the fuel and oxidizer because the base is lifted. That is, the premixed character of the reaction kernel actually allows the HBr in the catalytic cycle to be more effective there because of the effective overlap between the Br and the hydrocarbon species, which allows efficient regeneration of HBr. (c) 2007 Published by Elsevier Inc. on behalf of The Combustion Institute. C1 Natl Inst Stand & Technol, Fire Res Div, Gaithersburg, MD 20899 USA. NASA, Glenn Res Ctr, Natl Ctr Space Explorat Res Fluids & Combust, Cleveland, OH 44135 USA. Innovat Sci Solut Inc, Dayton, OH 45440 USA. RP Linteris, GT (reprint author), Natl Inst Stand & Technol, Fire Res Div, Gaithersburg, MD 20899 USA. EM linteris@nist.gov NR 68 TC 25 Z9 25 U1 3 U2 7 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD APR PY 2007 VL 149 IS 1-2 BP 91 EP 103 DI 10.1016/j.combustflame.2006.12.013 PG 13 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 156OV UT WOS:000245659700008 ER PT J AU Sun, YZ Wang, ZJ Liu, Y AF Sun, Yuzhi Wang, Z. J. Liu, Yen TI High-order multidomain spectral difference method for the Navier-Stokes equations on unstructured hexahedral grids SO COMMUNICATIONS IN COMPUTATIONAL PHYSICS LA English DT Article DE high order; unstructured grids; spectral difference; Navier-Stokes ID FINITE VOLUME METHOD; DISCONTINUOUS GALERKIN METHOD; LOW REYNOLDS-NUMBERS; CONSERVATION-LAWS; TRIANGULAR MESHES; CIRCULAR-CYLINDER; ELEMENT METHOD; SCHEMES; SYSTEMS; EXTENSION AB A high order multidomain spectral difference method has been developed for the three dimensional Navier-Stokes equations on unstructured hexahedral grids. The method is easy to implement since it involves one-dimensional operations only, and does not involve surface or volume integrals. Universal reconstructions are obtained by distributing solution and flux points in a geometrically similar manner in a unit cube. The concepts of the Riemann solver and high-order local representations are applied to achieve conservation and high order accuracy. In this paper, accuracy studies are performed to numerically verify the order of accuracy using flow problems with analytical solutions. High order of accuracy and spectral convergence are obtained for the propagation of an isotropic vortex and Couette flow. The capability of the method for both inviscid and viscous flow problems with curved boundaries is also demonstrated. C1 Iowa State Univ, Dept Aerosp Engn, Ames, IA 50011 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Wang, ZJ (reprint author), Iowa State Univ, Dept Aerosp Engn, 2271 Howe Hall, Ames, IA 50011 USA. EM sunyuzhi@iastate.edu; zjw@iastate.edu; Yen.Liu@nasa.gov RI Wang, Z.J./A-9628-2010 OI Wang, Z.J./0000-0002-6203-6303 NR 40 TC 57 Z9 61 U1 1 U2 4 PU GLOBAL SCIENCE PRESS PI WANCHAI PA ROOM 3208, CENTRAL PLAZA, 18 HARBOUR RD, WANCHAI, HONG KONG 00000, PEOPLES R CHINA SN 1815-2406 J9 COMMUN COMPUT PHYS JI Commun. Comput. Phys. PD APR PY 2007 VL 2 IS 2 BP 310 EP 333 PG 24 WC Physics, Mathematical SC Physics GA 150HN UT WOS:000245206500007 ER PT J AU Balasubramanian, K Sidick, E Wilson, DW Hoppe, DJ Shaklan, SB Trauger, JT AF Balasubramanian, Kunjithapatham Sidick, Erkin Wilson, Daniel W. Hoppe, Daniel J. Shaklan, Stuart B. Trauger, John T. TI Band-limited masks for TPF coronagraph SO COMPTES RENDUS PHYSIQUE LA English DT Article DE TPF coronagraph; occulting mask; band-limited mask; HCIT ID IMAGE MASKS; PLANET AB Band-limited image plane masks, in conjunction with appropriate Lyot stops, function effectively to suppress host star light while transmitting planet light to the final image for detecting and characterizing faint exo-solar terrestrial planets. In this article, we review various types of image plane masks, their design, fabrication, and characterization. Measured characteristics and performance of sample masks in simulations and in laboratory experiments are also discussed. Star light suppression contrast better than 10(-9) in the 4 to 10 lambda/D region has been demonstrated with such a mask in our laboratory testbed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Balasubramanian, K (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM kbala@jpl.nasa.gov NR 14 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS PA 23 RUE LINOIS, 75724 PARIS, FRANCE SN 1631-0705 J9 CR PHYS JI C. R. Phys. PD APR-MAY PY 2007 VL 8 IS 3-4 BP 288 EP 297 DI 10.1016/j.crhy.2007.03.001 PG 10 WC Astronomy & Astrophysics; Physics, Multidisciplinary SC Astronomy & Astrophysics; Physics GA 202JD UT WOS:000248896900003 ER PT J AU Shao, M AF Shao, Michael TI Calibration of residual speckle in a nulling coronagraph SO COMPTES RENDUS PHYSIQUE LA English DT Article DE residual speckle; nulling coronagraph AB The most challenging aspect of the direct detection of planets around nearby stars is the huge brightness difference between planet and star associated to the very small angular separation of the two objects. This article describes the operation of a post coronagraph wavefront calibration system for measuring the residual speckle pattern, making use of the coherence of starlight. For a ground based AO coronagraph, the calibration interferometer potentially offers photon limited planet detection instead of atmospheric speckle limited detection. In a space based coronagraph, the use of the calibration system reduces the stability requirements of the optical system by several orders of magnitude. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shao, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM mshao@huey.jpl.nasa.gov NR 8 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS PA 23 RUE LINOIS, 75724 PARIS, FRANCE SN 1631-0705 J9 CR PHYS JI C. R. Phys. PD APR-MAY PY 2007 VL 8 IS 3-4 BP 340 EP 348 DI 10.1016/j.crhy.2007.03.002 PG 9 WC Astronomy & Astrophysics; Physics, Multidisciplinary SC Astronomy & Astrophysics; Physics GA 202JD UT WOS:000248896900008 ER PT J AU Borde, P Traub, W AF Borde, Pascal Traub, Wesley TI Speckle noise reduction techniques for high-dynamic range imaging SO COMPTES RENDUS PHYSIQUE LA English DT Article DE exoplanets; coronagraphy; speckles ID CORONAGRAPH; PLANETS; LIMITS; SPACE; HALO; MASK AB High-dynamic range imaging from space in the visible light range, aiming, in particular, at the detection of terrestrial exoplanets, necessitates not only the use of a coronagraph, but also of adaptive optics to correct optical defects in real time. Indeed, these defects scatter light and give birth to speckles in the image plane. Speckles can be cancelled by driving a deformable mirror to measure and compensate wavefront aberrations. In a first approach, targeted speckle nulling, speckles are cancelled iteratively by starting with the brightest ones. This first method has demonstrated a contrast better than 109 in laboratory. In a second approach, zonal speckle nulling, the total energy of speckles is minimized in a given zone of the image plane. This second method has the advantage of tackling simultaneously all speckles from the targeted zone, but it still needs better experimental demonstration. C1 Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. CNRS, UMR 8617, F-91405 Orsay, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Borde, P (reprint author), Univ Paris 11, Inst Astrophys Spatiale, Batiment 121, F-91405 Orsay, France. EM pascal.borde@ias.u-psud.fr; wesley.a.traub@jpl.nasa.gov NR 22 TC 5 Z9 5 U1 1 U2 1 PU ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS PA 23 RUE LINOIS, 75724 PARIS, FRANCE SN 1631-0705 J9 CR PHYS JI C. R. Phys. PD APR-MAY PY 2007 VL 8 IS 3-4 BP 349 EP 354 DI 10.1016/j.crhy.2007.04.004 PG 6 WC Astronomy & Astrophysics; Physics, Multidisciplinary SC Astronomy & Astrophysics; Physics GA 202JD UT WOS:000248896900009 ER PT J AU Macintosh, B Graham, J Palmer, D Doyon, R Gavel, D Larkin, J Oppenheimer, B Saddlemyer, L Wallace, JK Bauman, B Erikson, D Poyneer, L Sivaramakrishnan, A Soummer, R Veran, JP AF Macintosh, Bruce Graham, James Palmer, David Doyon, Rene Gavel, Don Larkin, James Oppenheimer, Ben Saddlemyer, Leslie Wallace, J. Kent Bauman, Brian Erikson, Darren Poyneer, Lisa Sivaramakrishnan, Anand Soummer, Remi Veran, Jean-Pierre TI Adaptive optics for direct detection of extrasolar planets: the Gemini Planet Imager SO COMPTES RENDUS PHYSIQUE LA English DT Article AB The direct detection of photons emitted or reflected by extrasolar planets, spatially resolved from their parent star, is a major frontier in the study of other solar systems. Direct detection will provide statistical information on planets in 5-50 AU orbits, inaccessible to current Doppler searches, and allow spectral characterization of radius, temperature, surface gravity, and perhaps composition. Achieving this will require new, dedicated, high-contrast instruments. One such system under construction is the Gemini Planet Imager (GPI). This combines a high-order/high-speed adaptive optics system to control wavefront errors from the Earth's atmosphere, an advanced coronagraph to block diffraction, ultrasmooth optics, a precision infrared interferometer to measure and correct systematic errors, and a integral field spectrograph/polarimeter to image and characterize target planetary systems. We predict that GPI will be able to detect planets with brightness less than 10(-7) of their parent star, sufficient to observe warm self-luminous planets around a large population of targets. C1 Univ Calif Santa Cruz, NSF Ctr Adapt Opt, Santa Cruz, CA 95064 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Montreal, Dept Phys, Montreal, PQ H3C 3J7, Canada. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Amer Museum Nat Hist, Dept Astrophys, New York, NY 10024 USA. Dominion Astrophys Observ, Herzberg Inst Astrophys, Victoria, BC V8X 4M6, Canada. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Macintosh, B (reprint author), Univ Calif Santa Cruz, NSF Ctr Adapt Opt, Santa Cruz, CA 95064 USA. EM bmac@igpp.llnl.gov NR 16 TC 19 Z9 19 U1 0 U2 3 PU ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS PA 23 RUE LINOIS, 75724 PARIS, FRANCE SN 1631-0705 J9 CR PHYS JI C. R. Phys. PD APR-MAY PY 2007 VL 8 IS 3-4 BP 365 EP 373 DI 10.1016/j.crhy.2007.04.007 PG 9 WC Astronomy & Astrophysics; Physics, Multidisciplinary SC Astronomy & Astrophysics; Physics GA 202JD UT WOS:000248896900011 ER PT J AU Danchi, WC Lopez, B AF Danchi, William C. Lopez, Bruno TI The Fourier-Kelvin Stellar Interferometer (FKSI) - A practical infrared space interferometer on the path to the discovery and characterization of Earth-like planets around nearby stars SO COMPTES RENDUS PHYSIQUE LA English DT Article DE nulling interferometer; extrasolar planets; planet formation; debris disks; active galactic nuclei ID EXTRASOLAR GIANT PLANETS; SOLAR-TYPE STARS; B-LIKE PLANETS; DUSTY DEBRIS; EVOLUTION; ATMOSPHERE; EMISSION; SYSTEM; DISK AB During the last few years, considerable effort has been directed towards large-scale (>$I billion USD) missions to detect and characterize Earth-like planets around nearby stars, such as the Terrestrial Planet Finder Interferometer (TPF-I) and Darwin missions. However, technological issues such as formation flying, cryocooling, null depth for broadband signals, control of systematic noise sources, budgetary pressures, and shifting science priorities at NASA and ESA, will prevent these missions from entering Phase A until the middle of the next decade. A simplified nulling interferometer operating in the near- to mid-infrared (e.g. similar to 3-8 microns), like the Fourier-Kelvin Stellar Interferometer (FKSI), can characterize the atmospheres of a large sample of the known planets. Many other scientific problems can be addressed with a system like FKSI, including the imaging of debris disks, active galactic nuclei, and low mass companions around nearby stars. We discuss the rationale, both scientific and technological, for a competed mission in the $450-600 million (USD) range, of which FKSI is an example. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Observ Cote Azur, UMR 6203, F-06304 Nice 4, France. RP Danchi, WC (reprint author), NASA, Goddard Space Flight Ctr, Code 667, Greenbelt, MD 20771 USA. EM wdanchi@milkyway.gsfc.nasa.gov; lopez@obs-nice.fr NR 47 TC 12 Z9 12 U1 0 U2 0 PU ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS PA 23 RUE LINOIS, 75724 PARIS, FRANCE SN 1631-0705 J9 CR PHYS JI C. R. Phys. PD APR-MAY PY 2007 VL 8 IS 3-4 BP 396 EP 407 DI 10.1016/j.crhy.2007.04.002 PG 12 WC Astronomy & Astrophysics; Physics, Multidisciplinary SC Astronomy & Astrophysics; Physics GA 202JD UT WOS:000248896900014 ER PT J AU Pusey, ML Paley, MS Turner, MB Rogers, RD AF Pusey, Marc L. Paley, Mark Steve Turner, Megan B. Rogers, Robin D. TI Protein crystallization using room temperature ionic liquids SO CRYSTAL GROWTH & DESIGN LA English DT Article ID ETHYLAMMONIUM NITRATE; AMINO-ACIDS; SALTS; STABILITY; SOLVENTS; BIOCATALYSIS; CANAVALIN AB The ionic liquids (ILs) 1-butyl-3-methylimidizolium chloride ([C(4)mim]Cl), 1-butyl-3-methylimidizolium 2(2-methoxyethoxy)ethylsulfate ([C(4)mim][MDEGSO4]), and 1-butyl-1-methylpyrollidinium dihydrogenphosphate ([p1,4][DHP]) were tested for their effects on the crystallization of the proteins canavalin, beta-lactoglobulin B, xylanase, and glucose isomerase, using a standard high throughput screen. The crystallization experiments were set up with the ILs added to the protein solutions at 0.2 and 0.4 M final concentrations. Crystallization droplets were set up at three protein/precipitant ratios (1:1, 2:1, and 4:1), which served to progressively dilute the effects of the screen components while increasing the equilibrium protein and IL concentrations. Crystals were obtained for all four proteins at a number of conditions where they were not obtained from IL-free control experiments. Over half of the protein-IL combinations tested had more successful outcomes than negative outcomes, where the IL-free crystallization was better than the corresponding IL-containing outcome, relative to the control. One of the most common causes of a negative outcome was solubilization of the protein by the IL, resulting in a clear drop. In one instance, we were able to use the IL-induced solubilizing to obtain beta-lactoglobulin B crystals from conditions that gave precipitated protein in the absence of IL. The results suggest that it may be feasible to develop ILs specifically for the task of macromolecule crystallization. C1 MI Res Inc, Huntsville, AL 35816 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Ctr Green Mfg, Tuscaloosa, AL 35487 USA. Univ Alabama, Alabama Inst Mfg Excellence, Tuscaloosa, AL 35487 USA. RP Pusey, ML (reprint author), MI Res Inc, Suite 109,515 Sparkman Dr, Huntsville, AL 35816 USA. EM marc@mi-research.com RI Rogers, Robin/C-8265-2013 OI Rogers, Robin/0000-0001-9843-7494 NR 51 TC 59 Z9 63 U1 4 U2 24 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1528-7483 J9 CRYST GROWTH DES JI Cryst. Growth Des. PD APR PY 2007 VL 7 IS 4 BP 787 EP 793 DI 10.1021/cg060696t PG 7 WC Chemistry, Multidisciplinary; Crystallography; Materials Science, Multidisciplinary SC Chemistry; Crystallography; Materials Science GA 153CD UT WOS:000245408400034 ER PT J AU Brewer, R AF Brewer, Ron TI Spacecraft EMC problems - Part 1 SO EE-EVALUATION ENGINEERING LA English DT Article C1 NASA, Analex, Kennedy Space Ctr, FL 32899 USA. RP Brewer, R (reprint author), NASA, Analex, Kennedy Space Ctr, FL 32899 USA. EM ronbrewer@ieee.org NR 0 TC 0 Z9 0 U1 0 U2 0 PU NELSON PUBLISHING PI NOKOMIS PA 2500 NORTH TAMIAMI TRAIL, NOKOMIS, FL 34275-3482 USA SN 0149-0370 J9 EE-EVAL ENG JI EE-Eval. Eng. PD APR PY 2007 VL 46 IS 4 BP 56 EP + PG 7 WC Engineering, Electrical & Electronic SC Engineering GA 153ZU UT WOS:000245477400009 ER PT J AU Finke, N Hoehler, TM Jorgensen, BB AF Finke, Niko Hoehler, Tori Michael Jorgensen, Bo Barker TI Hydrogen 'leakage' during methanogenesis from methanol and methylamine: implications for anaerobic carbon degradation pathways in aquatic sediments SO ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID SULFATE-REDUCING BACTERIA; INTERSPECIES H-2 TRANSFER; ANOXIC MARINE SEDIMENT; VOLATILE FATTY-ACIDS; METHANOSARCINA-BARKERI; METHANOBACILLUS-OMELIANSKII; PADDY SOIL; SP-NOV; ACETATE; REDUCTION AB The effect of variations in H-2 concentrations on methanogenesis from the non-competitive substrates methanol and methylamine (used by methanogens but not by sulfate reducers) was investigated in methanogenic marine sediments. Imposed variations in sulfate concentration and temperature were used to drive systematic variations in pore water H-2 concentrations. Specifically, increasing sulfate concentrations and decreasing temperatures both resulted in decreasing H-2 concentrations. The ratio of CO2 and CH4 produced from C-14-labelled methylamine and methanol showed a direct correlation with the H-2 concentration, independent of the treatment, with lower H-2 concentrations resulting in a shift towards CO2. We conclude that this correlation is driven by production of H-2 by methylotrophic methanogens, followed by loss to the environment with a magnitude dependent on the extracellular H-2 concentrations maintained by hydrogenotrophic methanogens (in the case of the temperature experiment) or sulfate reducers (in the case of the sulfate experiment). Under sulfate-free conditions, the loss of reducing power as H-2 flux out of the cell represents a loss of energy for the methylotrophic methanogens while, in the presence of sulfate, it results in a favourable free energy yield. Thus, hydrogen leakage might conceivably be beneficial for methanogens in marine sediments dominated by sulfate reduction. In low-sulfate systems such as methanogenic marine or freshwater sediments it is clearly detrimental - an adverse consequence of possessing a hydrogenase that is subject to externally imposed control by pore water H-2 concentrations. H-2 leakage in methanogens may explain the apparent exclusion of acetoclastic methanogenesis in sediments dominated by sulfate reduction. C1 Max Planck Inst Marine Microbiol, Dept Biogeochem, D-28359 Bremen, Germany. NASA Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. RP Finke, N (reprint author), Max Planck Inst Marine Microbiol, Dept Biogeochem, Celsiusstr 1, D-28359 Bremen, Germany. EM nfinke@web.de RI Jorgensen, Bo/C-2214-2013 OI Jorgensen, Bo/0000-0001-9398-8027 NR 48 TC 18 Z9 19 U1 2 U2 21 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 1462-2912 J9 ENVIRON MICROBIOL JI Environ. Microbiol. PD APR PY 2007 VL 9 IS 4 BP 1060 EP 1071 DI 10.1111/j.1462-2920.2007.01248.x PG 12 WC Microbiology SC Microbiology GA 144DQ UT WOS:000244776200021 PM 17359276 ER PT J AU Hansen, JE AF Hansen, J. E. TI Scientific reticence and sea level rise SO ENVIRONMENTAL RESEARCH LETTERS LA English DT Article DE sea level; global warming; glaciology; ice sheets ID ANTARCTIC ICE-SHEET; ATMOSPHERIC CARBON-DIOXIDE; CLIMATE; GREENHOUSE; PENINSULA; GREENLAND; SHELF; COLLAPSE; SNOWFALL; GROWTH AB I suggest that a 'scientific reticence' is inhibiting the communication of a threat of a potentially large sea level rise. Delay is dangerous because of system inertias that could create a situation with future sea level changes out of our control. I argue for calling together a panel of scientific leaders to hear evidence and issue a prompt plain-written report on current understanding of the sea level change issue. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Hansen, JE (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM jhansen@giss.nasa.gov NR 52 TC 65 Z9 65 U1 4 U2 13 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 1748-9326 J9 ENVIRON RES LETT JI Environ. Res. Lett. PD APR-JUN PY 2007 VL 2 IS 2 AR 024002 DI 10.1088/1748-9326/2/2/024002 PG 6 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 269MJ UT WOS:000253652800002 ER PT J AU Boone, RB Lackett, JM Galvin, KA Ojima, DS Tucker, CJ AF Boone, Randall B. Lackett, Jill M. Galvin, Kathleen A. Ojima, Dennis S. Tucker, Compton J., III TI Links and broken chains: evidence of human-caused changes in land cover in remotely sensed images SO ENVIRONMENTAL SCIENCE & POLICY LA English DT Article DE land cover; Landsat GeoCover; change detection; image differencing; NDVI ID UNSUPERVISED CHANGE-DETECTION; GROUP RANCH SUBDIVISION; VEGETATION; NDVI; CONSERVATION; LIVESTOCK; PATTERNS; KAJIADO; IMPACTS; AFRICA AB Land use intensification on shrinking forage resources characterizes many livestock producing communities. Remotely sensed images can show land cover change, but how household decision making is reflected in images had not been synthesized. For eight areas in the US, Africa, and Mongolia (>340,000 km(2)), we ranked constraints in decision making, and quantified vegetation greenness trends from 1981 to 2004 and land cover change using 1990 and 2000 Landsat images. Constraints in decision making varied across the sites, but ecological settings ranked highest. Five sites showed increasing greenness (2.4-8.0% increase per decade; P <= 0.01); the African sites showed no change or declining greenness (-2.5%; P = 0.048). Land cover change in the US sites was modest, with most sites suitable for cultivation already converted by 1990. Cover change was minor in Mongolia, despite profound changes in government and economy. The Kenyan site showed the largest change in land cover. We hypothesize a humped relationship, where households in undeveloped regions lack the resources to convert land cover. Developed regions have reached some stasis in land use. Developing regions with high human population growth and residents with access to machinery show the greatest land cover change. (C) 2007 Elsevier Ltd. All rights reserved. C1 Colorado State Univ, Nat Resource Ecol Lab, Ft Collins, CO 80523 USA. Colorado State Univ, Dept Anthropol, Ft Collins, CO 80523 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Boone, RB (reprint author), Colorado State Univ, Nat Resource Ecol Lab, 1499 campus Delivery,B234 NESB, Ft Collins, CO 80523 USA. EM rboone@nrel.colostate.edu RI Boone, Randall/N-6566-2013; Ojima, Dennis/C-5272-2016 NR 74 TC 10 Z9 11 U1 0 U2 7 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1462-9011 J9 ENVIRON SCI POLICY JI Environ. Sci. Policy PD APR PY 2007 VL 10 IS 2 BP 135 EP 149 DI 10.1016/j.envsci.2006.09.006 PG 15 WC Environmental Sciences SC Environmental Sciences & Ecology GA 143PQ UT WOS:000244735400004 ER PT J AU Tubiello, FN Amthor, JS Boote, KJ Donatelli, M Easterling, W Fischer, G Gifford, RM Howden, M Reilly, J Rosenzweig, C AF Tubiello, Francesco N. Amthor, Jeffrey S. Boote, Kenneth J. Donatelli, Marcello Easterling, William Fischer, Gunther Gifford, Roger M. Howden, Mark Reilly, John Rosenzweig, Cynthia TI Crop response to elevated CO2 and world food supply - A comment on "Food for Thought..." by Long et al., Science 312 : 1918-1921, 2006 SO EUROPEAN JOURNAL OF AGRONOMY LA English DT Editorial Material DE CO2; crop response; FACE; chambers; experimental and model data; climate change; world food supply ID ATMOSPHERIC CARBON-DIOXIDE; CLIMATE-CHANGE; ENRICHMENT FACE; PHOTOSYNTHESIS; YIELD; MODEL; GROWTH; WHEAT; AGRICULTURE; IMPACTS AB Recent conclusions that new free-air carbon dioxide enrichment (FACE) data show a much lower crop yield response to elevated CO2 than thought previously - casting serious doubts on estimates of world food supply in the 21 st century - are found to be incorrect, being based in part on technical inconsistencies and lacking statistical significance. First, we show that the magnitude of crop response to elevated CO2 is rather similar across FACE and non-FACE data-sets, as already indicated by several previous comprehensive experimental and modeling analyses, with some differences related to which "ambient" CO2 concentration is used for comparisons. Second, we find that results from most crop model simulations are consistent with the values from FACE experiments. Third, we argue that lower crop responses to elevated CO2 of the magnitudes in question would not significantly alter projections of world food supply. We conclude by highlighting the importance of a better understanding of crop response to elevated CO, under a variety of experimental and modeling settings, and suggest steps necessary to avoid confusion in future meta-analyses and comparisons of experimental and model data. (c) 2006 Elsevier B.V. All rights reserved. C1 Columbia Univ, Ctr Climate Syst Res, New York, NY USA. US DOE, Off Sci, Washington, DC 20585 USA. Univ Florida, Dept Agron, Gainesville, FL USA. ISCI, CRA, Bologna, Italy. Penn State Univ, Penn State Inst Environm, University Pk, PA USA. Int Inst Appl Syst Anal, Land Use Program, Laxenburg, Austria. CSIRO, Plant Ind, Canberra, ACT, Australia. CSIRO, Sustainable Ecosyst, Canberra, ACT, Australia. MIT, Joint Program Sci Policy Global Change, Cambridge, MA 02139 USA. NASA, Goddard Inst Space Studies, Climate Impacts Grp, New York, NY USA. RP Tubiello, FN (reprint author), Int Inst Appl Syst Anal, Schlosspl 1, A-2361 Laxenburg, Austria. EM franci@giss.nasa.gov RI Howden, Stuart/C-1138-2008; Amthor, Jeffrey/F-2696-2016; OI Howden, Stuart/0000-0002-0386-9671; Amthor, Jeffrey/0000-0002-1410-6100; Boote, Kenneth/0000-0002-1358-5496 NR 41 TC 144 Z9 158 U1 1 U2 45 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1161-0301 J9 EUR J AGRON JI Eur. J. Agron. PD APR PY 2007 VL 26 IS 3 BP 215 EP 223 DI 10.1016/j.eja.2006.10.002 PG 9 WC Agronomy SC Agriculture GA 156BW UT WOS:000245623900005 ER PT J AU Richards, JT Mulavara, AP Bloomberg, JJ AF Richards, Jason T. Mulavara, Ajitkumar P. Bloomberg, Jacob J. TI The interplay between strategic and adaptive control mechanisms in plastic recalibration of locomotor function SO EXPERIMENTAL BRAIN RESEARCH LA English DT Article ID POSTERIOR PARIETAL CORTEX; SENSORIMOTOR ADAPTATION; VIRTUAL ENVIRONMENT; PRISM ADAPTATION; TREADMILL LOCOMOTION; SPATIAL ALIGNMENT; OPTICAL-ROTATION; WALKING; VISION; SYSTEM AB We have previously shown that viewing simulated rotary self-motion during treadmill locomotion causes immediate strategic modifications (Richards et al. in Presence Teleoper Vir Real 13:371-384, 2004) as well as an after effect reflecting adaptive modification of the control of position and trajectory during over-ground locomotion (Mulavara et al. in Exp Brain Res 166:210-219, 2005). The process of sensorimotor adaptation is comprised of both strategic and adaptive control mechanisms. Strategic control involves cognitive, on-line corrections to motor outputs once one is aware of a sensory discordance. Over an extended period of exposure to the sensory discordance, new strategic sensorimotor coordination patterns are reinforced until they become more automatic, and therefore adaptive in nature. The objective of this study was to investigate how strategic changes in trunk control during exposure to simulated rotary self-motion during treadmill walking influences adaptive modification of locomotor heading direction during over-ground stepping. Subjects (n = 10) walked on a motorized linear treadmill while viewing a wide field-of-view virtual scene for 24 min. The scene was static for the first 4 min and then, for the last 20 min, depicted constant rate self-motion equivalent to walking in a counter-clockwise, circular path around the perimeter of a room. Subjects performed five stepping trials both before and after the exposure period to assess after effects. Results from our previous study showed a significant change in heading direction (HD) during post-exposure step tests that was opposite to the direction in which the scene rotated during the adaptation period. For the present study, we quantified strategic modifications in trunk movement control during scene exposure using normalized root mean square (R (P)) variation of the subject's 3D trunk positions and normalized sum of standard deviations (R (O)) variation of 3D trunk orientations during scene rotation relative to that during static scene presentation. Associated 95% confidence intervals, CIP and CIO, were calculated to investigate the variation of strategic modifications during scene exposure. Repeated measures ANOVA and individual subject regression analyses showed that R (P) and R (O) (i.e. strategic modifications) for trunk fore/aft (X) positions and yaw rotations, respectively, decreased significantly over the exposure period. Furthermore, we found a significant correlation between the magnitude change in HD and the rate at which the variation of strategic modifications in trunk X decreased. We also found evidence of a correlation between HD and the rate at which strategic modifications in trunk yaw decreased. We infer that adaptive recalibration of locomotor trajectory using optic flow stimuli depends on the rate at which kinematic variability associated with strategic control is reduced. C1 Univ Space Res Assoc, Neurosci Lab, Houston, TX USA. Wyle Labs, Neurosci Lab, Houston, TX 77058 USA. NASA, Neurosci Lab, JSC, Houston, TX USA. RP Mulavara, AP (reprint author), Univ Space Res Assoc, Neurosci Lab, Houston, TX USA. EM jrichards@alum.mit.edu NR 62 TC 13 Z9 13 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0014-4819 J9 EXP BRAIN RES JI Exp. Brain Res. PD APR PY 2007 VL 178 IS 3 BP 326 EP 338 DI 10.1007/s00221-006-0738-6 PG 13 WC Neurosciences SC Neurosciences & Neurology GA 148VQ UT WOS:000245105500005 PM 17061092 ER PT J AU Baer, L Wade, C Ronca, A AF Baer, Lisa Wade, Charles Ronca, April TI Effects of chronic prenatal stress on adult body weight, percent body fat weight and plasma leptin in male rats SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2007 Annual Meeting CY APR 28-MAY 02, 2007 CL Washington, DC C1 USA, Inst Surg Res, Ft Sam Houston, TX 78234 USA. NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. Wake Forest Univ, Sch Med, Winston Salem, NC 27157 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD APR PY 2007 VL 21 IS 6 BP A1420 EP A1420 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 157HF UT WOS:000245708705432 ER PT J AU Evans, JM Meng, ME Platts, SH Stenger, MB Diedrich, A Natapoff, A Knapp, CF AF Evans, Joyce M. Meng, Martha E. Platts, Steven H. Stenger, Michael B. Diedrich, Andre Natapoff, Alan Knapp, Charles F. TI Artificial gravity training helps maintain cardiovascular function in subjects deconditioned by bed rest SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2007 Annual Meeting CY APR 28-MAY 02, 2007 CL Washington, DC SP Amer Assoc Anatomists, Amer Physiol Soc, Amer Soc Biochem & Mol biol, Amer Soc Investigat Pathol, Amer Soc Nutr, Amer Soc Pharmacol & Expt Therapeut C1 Univ Kentucky, Ctr Biomed Engn, Lexington, KY 40506 USA. Lyndon B Johnson Space Ctr, Houston, TX 77508 USA. Vanderbilt Univ, Nashville, TN 37232 USA. MIT, Cambridge, MA 02139 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD APR PY 2007 VL 21 IS 6 BP A952 EP A952 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 157HF UT WOS:000245708701475 ER PT J AU Gopalakrishnan, G Baker, E Serrador, JM Wood, SJ AF Gopalakrishnan, Gosala Baker, Eliot Serrador, Jorge M. Wood, Scott J. TI Impaired vestibular function affects orthostatic cerebral blood flow response SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2007 Annual Meeting CY APR 28-MAY 02, 2007 CL Washington, DC C1 Beth Israel Deaconess Med Ctr, Boston, MA 02215 USA. Harvard Univ, Sch Med, Boston, MA 02215 USA. Lyndon B Johnson Space Ctr, Houston, TX 77085 USA. RI Serrador, Jorge/A-9172-2009 NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD APR PY 2007 VL 21 IS 6 BP A1383 EP A1384 PG 2 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 157HF UT WOS:000245708705267 ER PT J AU Howarth, MS Schlegel, TT Knapp, CF Patwardhan, AR Jenkins, RA Ilgner, RH Evans, JM AF Howarth, Mark S. Schlegel, Todd T. Knapp, Charles F. Patwardhan, Abhijit R. Jenkins, Roger A. Ilgner, Ralph H. Evans, Joyce M. TI Cardiac autonomic effects of acute exposures to airborne particulates in men and women SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2007 Annual Meeting CY APR 28-MAY 02, 2007 CL Washington, DC C1 Univ Kentucky, Ctr Biomed Engn, Lexington, KY 40506 USA. NASA Johnson Space Ctr, Houston, TX 77058 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD APR PY 2007 VL 21 IS 5 BP A566 EP A566 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 157HD UT WOS:000245708504467 ER PT J AU Howarth, MS Moore, FB Hinghofer-Szalkay, H Jantscher, A Stenger, MB Diedrich, A Patwardihan, AR Knapp, CF Evans, JM AF Howarth, Mark S. Moore, Fritz B. Hinghofer-Szalkay, Helmut Jantscher, Andreas Stenger, Michael B. Diedrich, Andre Patwardihan, Abhijit R. Knapp, Charles F. Evans, Joyce M. TI Cardiovascular responses to artificial gravity are modulated by radius of rotation and exercise SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2007 Annual Meeting CY APR 28-MAY 02, 2007 CL Washington, DC C1 Univ Kentucky, Ctr Biomed Engn, Lexington, KY 40506 USA. NASA, Ames Res Ctr, Gravitat Res Branch, Moffett Field, CA 94035 USA. Med Univ Graz, IAP, Graz, Austria. Vanderbilt Univ, Nashville, TN 37232 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD APR PY 2007 VL 21 IS 6 BP A951 EP A952 PG 2 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 157HF UT WOS:000245708701474 ER PT J AU Karunamuni, G Wikenheiser, J Parsons-Wingerter, P Watanabe, M AF Karunamuni, Ganga Wikenheiser, Jamie Parsons-Wingerter, Patricia Watanabe, Michiko TI Lymphatics of the avian embryonic heart SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2007 Annual Meeting CY APR 28-MAY 02, 2007 CL Washington, DC C1 Case Western Reserve Univ, Rainbow Babies & Childrens Hosp, Cleveland, OH 44106 USA. NASA, John Glenn Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD APR PY 2007 VL 21 IS 5 BP A230 EP A230 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 157HD UT WOS:000245708501540 ER PT J AU Parsons-Wingerter, PA McKay, TL Vickerman, MB Wernet, MP Myers, JG Radhakrishnan, K AF Parsons-Wingerter, Patricia A. McKay, Terri L. Vickerman, Mary B. Wernet, Mark P. Myers, Jerry G., Jr. Radhakrishnan, Krishnan TI Microvascular branching as a determinant of blood flow by intravital particle imaging velocimetry SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2007 Annual Meeting CY APR 28-MAY 02, 2007 CL Washington, DC C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ New Mexico, Albuquerque, NM 87131 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD APR PY 2007 VL 21 IS 5 BP A232 EP A232 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 157HD UT WOS:000245708501549 ER PT J AU Parsons-Wingerter, PA Vickerman, MB Mckay, TL Gedeon, DJ Keith, PA Kaiser, PK Sears, JE Ebrahem, Q Karunamuni, G Watanabe, M AF Parsons-Wingerter, Patricia A. Vickerman, Mary B. McKay, Terri L. Gedeon, Dan J. Keith, Patricia A. Kaiser, Peter K. Sears, Jonathan E. Ebrahem, Quteba Karunamuni, Ganga Watanabe, Michiko TI Rapid quantification of normal and abnormal blood and lymphatic vasculature SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2007 Annual Meeting CY APR 28-MAY 02, 2007 CL Washington, DC C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Cleveland Clin Fdn, Cole Eye Inst, Cleveland, OH 44195 USA. Case Western Reserve Univ, Sch Med, Cleveland, OH 44106 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD APR PY 2007 VL 21 IS 5 BP A88 EP A88 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 157HD UT WOS:000245708500420 ER PT J AU Smith, SM Zwart, SR Gillman, PL Crawford, GE LeBlanc, A Shackelford, LC Heer, MA AF Smith, Scott M. Zwart, Sara R. Gillman, Patricia L. Crawford, Glenda E. LeBlanc, Adrian Shackelford, Linda C. Heer, Martina A. TI Artificial gravity as a bone loss countermeasure in simulated weightlessness SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2007 Annual Meeting CY APR 28-MAY 02, 2007 CL Washington, DC C1 NASA, Lyndon B Johnson Space Ctr, Human Adaptat & Countermeasures Off, Houston, TX 77573 USA. Univ Space Res Assoc, Human Adaptat & Countermeasures, Houston, TX 77573 USA. EASI, Houston, TX 77058 USA. DLR, Inst Aerospace Med, Cologne, Germany. NR 0 TC 0 Z9 0 U1 2 U2 2 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD APR PY 2007 VL 21 IS 5 BP A174 EP A174 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 157HD UT WOS:000245708501266 ER PT J AU Zwart, SR Heer, M Lee, SMC Macias, B Schneider, S Trappe, S Trappe, T Hargens, A Smith, SM AF Zwart, Sara R. Heer, Martina Lee, Stuart M. C. Macias, Brandon Schneider, Suzanne Trappe, Scott Trappe, Todd Hargens, Alan Smith, Scott M. TI Wise-2005: Combined aerobic and resistive exercise may help mitigate bone loss during 60-D simulated microgravity in women SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2007 Annual Meeting CY APR 28-MAY 02, 2007 CL Washington, DC C1 USRA, Houston, TX 77058 USA. DLR, Cologne, Germany. Wyle, Houston, TX 77058 USA. Univ Calif San Diego, San Diego, CA 92103 USA. Univ New Mexico, Albuquerque, NM 87131 USA. Ball State Univ, Human Performance Lab, Muncie, IN 47306 USA. NASA, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD APR PY 2007 VL 21 IS 5 BP A174 EP A174 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 157HD UT WOS:000245708501265 ER PT J AU Zeller, D Booth, S Davis, G Pauly, D AF Zeller, Dirk Booth, Shawn Davis, Gerald Pauly, Daniel TI Re-estimation of small-scale fishery catches for US flag-associated island areas in the western Pacific: the last 50 years SO FISHERY BULLETIN LA English DT Article ID AMERICAN-SAMOA AB Nearshore fisheries in the tropical Pacific play an important role, both culturally and as a reliable source of food security, but often remain under-reported in statistics, leading to undervaluation of their importance to communities. We re-estimated nonpelagic catches for Guam and the Commonwealth of the Northern Mariana Islands (CNMI), and summarize previous work for American Samoa for 1950-200. or all islands combined, catches declined by 77%, contrasting with increasing trends indicated by reported data. For individual island entities, re-estimation suggested declines of 86%, 54%, and 79% for Guam, CNMI, and American Samoa, respectively. Except for Guam, reported data primarily represented commercial catches, and hence under-represented contributions by subsistence and recreational fisheries. Guam's consistent use of creel surveys for data collection resulted in the most reliable reported catches for any of the islands considered. Our re-estimation makes the scale of under-reporting of total catches evident, and provides valuable baselines of likely historic patterns in fisheries catches. C1 Univ British Columbia, Fisheries Ctr, Vancouver, BC V6T 1Z4, Canada. Natl Ocean & Atmospher Adm, Natl Marine Fisheries Serv, Honolulu, HI 96814 USA. RP Zeller, D (reprint author), Univ British Columbia, Fisheries Ctr, 2202 Main Mall, Vancouver, BC V6T 1Z4, Canada. EM d.zeller@fisheries.ubc.ca NR 11 TC 83 Z9 83 U1 0 U2 14 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 2007 VL 105 IS 2 BP 266 EP 277 PG 12 WC Fisheries SC Fisheries GA 177JG UT WOS:000247148800009 ER PT J AU Pasek, MA Dworkin, JP Lauretta, DS AF Pasek, Matthew A. Dworkin, Jason P. Lauretta, Dante S. TI A radical pathway for organic phosphorylation during schreibersite corrosion with implications for the origin of life SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID CONTAINING INORGANIC RADICALS; AQUEOUS-SOLUTION; PHOSPHONIC-ACIDS; PREBIOTIC PHOSPHORUS; HYDROXYL RADICALS; HYDROGEN-PEROXIDE; EARLY EARTH; EVOLUTION; HYPOPHOSPHATE; PHOSPHATES AB Phosphorylated compounds (e.g., DNA, RNA, phospholipids, and many coenzymes) are critical to biochemistry. Thus, their origin is of prime interest to origin of life studies. The corrosion of the meteoritic mineral schreibersite ((Fe,Ni)(3)P) may have significantly contributed to the origin of phosphorylated biomolecules. Corrosion of synthetic schreibersite in a variety of solutions was analyzed by nuclear magnetic resonance spectroscopy, mass spectrometry, and electron paramagnetic resonance spectroscopy. These methods suggest a free-radical reaction pathway for the corrosion of schreibersite to form phosphite radicals ((.)PO(3)(2-)) in aqueous solution. These radicals can form activated polyphosphates and can phosphorylate organic compounds such as acetate to form phosphonates and organophosphates (3% total yield). Phosphonates (O(3)P-C) are found in the organic P inventory of the carbonaceous meteorite Murchison. While phosphonates are rare in biochemistry, the ubiquity of corroding iron meteorites on the early Earth could have provided a source of organic phosphorous compounds for the origin of life, and may have led to the role of organophosphates as a product of early evolution. (c) 2007 Elsevier Ltd. All rights reserved. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. NASA, Goddard Space Flight Ctr, Astrochem Branch, Greenbelt, MD USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RP Pasek, MA (reprint author), Univ Arizona, Steward Observ, 1629 E Univ Blvd, Tucson, AZ 85721 USA. EM Mpasek@lpl.arizona.edu RI Pasek, Matthew/A-7071-2008; OI Dworkin, Jason/0000-0002-3961-8997; Pasek, Matthew/0000-0003-1280-9555 NR 46 TC 42 Z9 47 U1 3 U2 24 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD APR 1 PY 2007 VL 71 IS 7 BP 1721 EP 1736 DI 10.1016/j.gca.2006.12.018 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 153OV UT WOS:000245445700006 ER PT J AU Parnell, J Bowden, SA Osinski, GR Lee, P Green, P Taylor, C Baron, M AF Parnell, John Bowden, Stephen A. Osinski, Gordon R. Lee, Pascal Green, Paul Taylor, Colin Baron, Martin TI Organic geochemistry of impactites from the Haughton impact structure, Devon Island, Nunavut, Canada SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID INDUCED HYDROTHERMAL ACTIVITY; ARCTIC CANADA; CRUDE OILS; SOURCE ROCKS; THERMAL MATURITY; HYDROCARBON BIOMARKERS; MIDDLE ORDOVICIAN; FLUID INCLUSIONS; MATTER; CRATER AB Organic matter in impactites from the 24 km wide and 39 Ma old Haughton impact structure, Canadian High Arctic, is a mixture of fossil and modern biological components. The fossil component represents a conventional oil that was generated from Lower Palaeozoic marine source material before impact and permeates bedrock dolomites. Biomarker maturity parameters record the thermal effect of the mid-Tertiary impact. Maturity-influenced sterane, rearranged hopanoid, and triaromatic steroid ratios all increase towards the centre of the impact structure, where thermal alteration was greatest. The heating was probably dominated by an impact-related hydrothermal system, as such systems last long enough for kinetically-based thermal alteration to occur. Kinetically-related biomarker data suggest that the hydrothermal heating lasted for c. 5000 years. Biomarkers are also preserved in dolomite clasts within impact melt breccia, and indicate strong thermal alteration. Modern biological contamination of the rocks is responsible for the superposition of two geochemical signatures (which could be cyanobacteria, non-marine algae, or higher plant matter) onto the fossil component, but they can be recognized and distinguished. The data show that the impact structure system holds a record of both the pre-impact organic signature and the thermal signature of the impact, and thereby indicates that organic geochemistry is a valuable tool in documenting the response of rocks to impacts. (c) 2007 Elsevier Ltd. All rights reserved. C1 Univ Aberdeen, Dept Geol & Petr Geol, Aberdeen AB24 3UE, Scotland. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. Geotrack Int Pty Ltd, Brunswick W, Vic 3055, Australia. RP Parnell, J (reprint author), Univ Aberdeen, Dept Geol & Petr Geol, Aberdeen AB24 3UE, Scotland. EM j.parnell@abdn.ac.uk NR 99 TC 18 Z9 18 U1 2 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD APR 1 PY 2007 VL 71 IS 7 BP 1800 EP 1819 DI 10.1016/j.gca.2007.01.006 PG 20 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 153OV UT WOS:000245445700011 ER PT J AU Asgharzadeh, MF von Frese, RRB Kim, HR Leftwich, TE Kim, JW AF Asgharzadeh, M. F. von Frese, R. R. B. Kim, H. R. Leftwich, T. E. Kim, J. W. TI Spherical prism gravity effects by Gauss-Legendre quadrature integration SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE gradient; gravity; satellite; tectonics ID CORRELATED FREE-AIR; GRAVITATIONAL ATTRACTION; ANOMALY CORRELATIONS; SPECTRAL CORRELATION; TERRAIN CORRECTIONS; CRUSTAL ANALYSIS; NORTH-ATLANTIC; EARTH GRAVITY; TOPOGRAPHY; MOON AB Satellite-measured regional gravity and terrain elevation data are becoming increasingly available for improving our understanding of the geological properties and history of the Earth, Moon, Mars, Venus and other planets. In assessing the geological significance of the existing and growing volumes of these regional data sets, there is great need for computing theoretical anomalous gravity fields from geological models in spherical coordinates. In the present study, we explicitly develop the elegant Gauss-Legendre quadrature formulation for numerically modelling the complete gravity effects (i.e. potential, vector and tensor gradient fields) of the spherical prism. As an application, we investigate the gradient components of the isostatic gravity anomalies that the upcoming Gravity Field and Steady State Ocean Circulation Explorer (GOCE) satellite mission is likely to map over a large tectonically active region of the Middle East centred on Iran. C1 Ohio State Univ, Sch Earth Sci, Columbus, OH 43210 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, NASA, GSFC, Greenbelt, MD 20771 USA. Sejong Univ, Dept Geoinformat Engn, Seoul 143747, South Korea. RP Asgharzadeh, MF (reprint author), Ohio State Univ, Sch Earth Sci, Columbus, OH 43210 USA. EM vonfrese@osu.edu NR 34 TC 21 Z9 22 U1 1 U2 9 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0956-540X EI 1365-246X J9 GEOPHYS J INT JI Geophys. J. Int. PD APR PY 2007 VL 169 IS 1 BP 1 EP 11 DI 10.1111/j.1365-246X.2007.03214.x PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 155WF UT WOS:000245608600001 ER PT J AU Emerson, CW Chinniah, S Lam, NSN Quattrochi, DA AF Emerson, Charles W. Chinniah, Sivagurtmathan Lam, Nina Siu-Ngan Quattrochi, Dale A. TI Spatial and grayscale metadata for similarity searches of image databases SO GISCIENCE & REMOTE SENSING LA English DT Article ID FRACTAL DIMENSION; INFORMATION; LACUNARITY; RETRIEVAL AB This paper presents a content-based image retrieval process wherein the user identifies a feature of interest using a region quadtree decomposition of the image, spatial statistics and histograms of the grayscale values of the feature definition are calculated, and the result is compared to a database of these same calculations that have been performed on similar images. The sum of squared differences between the indices calculated for the quads that form the feature of interest and corresponding quads in the database yields a ranked list of matching image tiles. In an analysis of Landsat 7 imagery of North Georgia and an IKONOS panchromatic image of Kalamazoo, Michigan, we found that the retrieval success rate depends on the spatial and spectral characteristics of the feature of interest and the configuration of quads used to define the feature. C1 Western Michigan Univ, Dept Geog, Kalamazoo, MI 49008 USA. PSMA Australia Ltd, Griffith, ACT 2603, Australia. Louisiana State Univ, Dept Environm Studies, Baton Rouge, LA 70803 USA. NASA, Earth Sci Off, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Emerson, CW (reprint author), Western Michigan Univ, Dept Geog, Kalamazoo, MI 49008 USA. EM charles.emerson@wmich.edu NR 25 TC 0 Z9 0 U1 0 U2 2 PU BELLWETHER PUBLISHING LTD PI COLUMBIA PA 8640 GUILFORD RD, STE 200, COLUMBIA, MD 21046 USA SN 1548-1603 J9 GISCI REMOTE SENS JI GISci. Remote Sens. PD APR-JUN PY 2007 VL 44 IS 2 BP 182 EP 201 DI 10.2747/1548-1603.44.2.182 PG 20 WC Geography, Physical; Remote Sensing SC Physical Geography; Remote Sensing GA 155FE UT WOS:000245562500005 ER PT J AU Gutman, G AF Gutman, Gank TI Contribution of the NASA Land-Cover/Land-Use Change Program to the Northern Eurasia Earth Science Partnership Initiative: An overview SO GLOBAL AND PLANETARY CHANGE LA English DT Article; Proceedings Paper CT 1st Science Session of the Northern-Eurasia-Earth-Science-Partnership-Initiative (NEESPI) held at the 2004 Fall AGU Meeting CY DEC 13-17, 2004 CL San Francisco, CA SP No Eurasia Earth Sci Partnership Initiat, AGU DE NASA; NEESPI; LCLUC ID CARBON; FORESTS; EMISSIONS; DYNAMICS; SIBERIA AB The Northern Eurasia Earth Science Partnership Initiative (NEESPI) is a rapidly growing program that involves national government agencies, academia and private organizations in the U.S., Europe, Japan and Northern Eurasia. During the last decade the Northern Eurasian region have been undergoing socioeconomic, climatic and demographic changes. The causes of these changes, the associated interactions between the land surface, the atmosphere and the surrounding ocean and the resultant impact on the sustainability of land use of the region are important topics for scientific research. The NEESPI Science Plan has been prepared as an integrated regional study to better understand these hemispheric-scale interactions, to evaluate the combined role of climate and anthropogenic impacts on the Northern Eurasia ecosystems, and to assess how future human actions would affect the global climate and ecosystems of the region. Projections of the consequence of global changes on the regional environment, the economy and the quality of life in Northern Eurasia that is of primary importance to the nations in the region is an additional focus of this initiative. The NASA Land-Cover/Land-Use Change (LCLUC) Program has supported NEESPI since its inception, and currently funds 26 NEESPI projects. Several other NASA programs are also currently supporting or planning to support the NEESPI. The NEESPI program links to the major international programs under the Earth System Science Partnership (IGBP, IHDP, DIVERSITAS and WCRP) and under the Global Terrestrial Observing System, such as the Global Observation of Forest Cover/Global Observation of Landcover Dynamics (GOFC/GOLD). A number of the NEESPI science activities are aligned with the Global Earth System of Systems (GEOSS) objectives, giving an emphasis to societal benefits, so that the NEESPI framework can serve as a regional test bed for international cooperation in developing a system of observational systems. Since it is a new program, most of the NEESPI research projects have just started. Therefore, rather than describing these projects this paper focuses on presenting some results of the longer term projects which are being continued under NEESPI, and on the expected products from the program and its future directions. More information on the projects can be found at http://neespi.org or http://lcluc.hq.nasa.gov. (C) 2006 Elsevier B.V. All rights reserved. C1 NASA Headquarters, Washington, DC USA. RP Gutman, G (reprint author), NASA Headquarters, Washington, DC USA. EM ggutman@nasa.gov NR 31 TC 3 Z9 3 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 EI 1872-6364 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD APR PY 2007 VL 56 IS 3-4 BP 235 EP 247 DI 10.1016/j.glopacha.2006.07.017 PG 13 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 168OI UT WOS:000246533500003 ER PT J AU Soja, AJ Tchebakova, NM French, NHF Flannigan, MD Shugart, HH Stocks, BJ Sukhinin, AI Parfenova, EI Chapin, FS Stackhouse, PW AF Soja, Amber J. Tchebakova, Nadezda M. French, Nancy H. F. Flannigan, Michael D. Shugart, Herman H. Stocks, Brian J. Sukhinin, Anatoly I. Parfenova, E. I. Chapin, F. Stuart, III Stackhouse, Paul W., Jr. TI Climate-induced boreal forest change: Predictions versus current observations SO GLOBAL AND PLANETARY CHANGE LA English DT Article; Proceedings Paper CT 1st Science Session of the Northern-Eurasia-Earth-Science-Partnership-Initiative (NEESPI) held at the 2004 Fall AGU Meeting CY DEC 13-17, 2004 CL San Francisco, CA SP No Eurasia Earth Sci Partnership Initiat, AGU DE climate change evidence; fire; infestation disturbance; treeline progression; boreal; montane ID TERRESTRIAL CARBON STORAGE; GLOBAL CLIMATE; ENVIRONMENTAL-FACTORS; SPATIAL-DISTRIBUTION; ECOLOGICAL PROCESSES; WHITE SPRUCE; FIRE; CANADA; MODEL; VEGETATION AB For about three decades, there have been many predictions of the potential ecological response in boreal regions to the currently warmer conditions. In essence, a widespread, naturally occurring experiment has been conducted over time. In this paper, we describe previously modeled predictions of ecological change in boreal Alaska, Canada and Russia, and then we investigate potential evidence of current climate-induced change. For instance, ecological models have suggested that warming will induce the northern and upslope migration of the treeline and an alteration in the current mosaic structure of boreal forests. We present evidence of the migration of keystone ecosystems in the upland and lowland treeline of mountainous regions across southern Siberia. Ecological models have also predicted a moisture-stress-related dieback in white spruce trees in Alaska, and current investigations show that as temperatures increase, white spruce tree growth is declining. Additionally, it was suggested that increases in infestation and wildfire disturbance would be catalysts that precipitate the alteration of the current mosaic forest composition. In Siberia, 7 of the last 9 yr have resulted in extreme fire seasons, and extreme fire years have also been more frequent in both Alaska and Canada. In addition, Alaska has experienced extreme and geographically expansive multi-year outbreaks of the spruce beetle, which had been previously limited by the cold, moist environment. We suggest that there is substantial evidence throughout the circumboreal region to conclude that the biosphere within the boreal terrestrial environment has already responded to the transient effects of climate change. Additionally, temperature increases and warming-induced change are progressing faster than had been predicted in some regions, suggesting a potential non-linear rapid response to changes in climate, as opposed to the predicted slow linear response to climate change. (C) 2006 Elsevier B.V. All rights reserved. C1 [Soja, Amber J.] NASA, Langley Res Ctr, Natl Inst Aerosp, Hampton, VA 23681 USA. [Tchebakova, Nadezda M.; Sukhinin, Anatoly I.; Parfenova, E. I.] Russian Acad Sci, Sukachev Inst Forestry, Krasnoyarsk 660036, Russia. [French, Nancy H. F.] Altarum Inst, Ann Arbor, MI 48113 USA. [Flannigan, Michael D.; Stocks, Brian J.] Canadian Forest Serv, Sault Ste Marie, ON P6A 2E5, Canada. [Shugart, Herman H.] Univ Virginia, Global Environm Change Program, Charlottesville, VA 22903 USA. [Shugart, Herman H.; Chapin, F. Stuart, III] Univ Alaska, Inst Arctic Biol, Fairbanks, AK 99775 USA. [Stackhouse, Paul W., Jr.] NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Soja, AJ (reprint author), NASA, Langley Res Ctr, Natl Inst Aerosp, Ctr21 Langley Blvd,Mail Stop 420, Hampton, VA 23681 USA. EM a.j.soja@larc.nasa.gov RI Shugart, Herman/C-5156-2009; Flannigan, Michael/G-6996-2015; OI French, Nancy/0000-0002-2389-3003; Flannigan, Michael/0000-0002-9970-5363; Chapin III, F Stuart/0000-0002-2558-9910 NR 167 TC 258 Z9 269 U1 25 U2 160 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 EI 1872-6364 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD APR PY 2007 VL 56 IS 3-4 BP 274 EP 296 DI 10.1016/j.gloplacha.2006.07.028 PG 23 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 168OI UT WOS:000246533500006 ER PT J AU Saatchi, SS Houghton, RA Alvala, RCDS Soares, JV Yu, Y AF Saatchi, S. S. Houghton, R. A. Alvala, R. C. Dos Santos Soares, J. V. Yu, Y. TI Distribution of aboveground live biomass in the Amazon basin SO GLOBAL CHANGE BIOLOGY LA English DT Article DE Amazon; biomass; climate; rainforest; remote sensing ID TROPICAL RAIN-FOREST; REMOTELY SENSED DATA; BRAZILIAN AMAZON; MAPPING DEFORESTATION; MULTISCALE TEXTURE; SPATIAL-PATTERNS; COLOMBIAN AMAZON; CARBON BALANCE; DECISION TREE; MAP ACCURACY AB The amount and spatial distribution of forest biomass in the Amazon basin is a major source of uncertainty in estimating the flux of carbon released from land-cover and land-use change. Direct measurements of aboveground live biomass (AGLB) are limited to small areas of forest inventory plots and site-specific allometric equations that cannot be readily generalized for the entire basin. Furthermore, there is no spaceborne remote sensing instrument that can measure tropical forest biomass directly. To determine the spatial distribution of forest biomass of the Amazon basin, we report a method based on remote sensing metrics representing various forest structural parameters and environmental variables, and more than 500 plot measurements of forest biomass distributed over the basin. A decision tree approach was used to develop the spatial distribution of AGLB for seven distinct biomass classes of lowland old-growth forests with more than 80% accuracy. AGLB for other vegetation types, such as the woody and herbaceous savanna and secondary forests, was directly estimated with a regression based on satellite data. Results show that AGLB is highest in Central Amazonia and in regions to the east and north, including the Guyanas. Biomass is generally above 300 Mg ha(-1) here except in areas of intense logging or open floodplains. In Western Amazonia, from the lowlands of Peru, Ecuador, and Colombia to the Andean mountains, biomass ranges from 150 to 300 Mg ha(-1). Most transitional and seasonal forests at the southern and northwestern edges of the basin have biomass ranging from 100 to 200 Mg ha(-1). The AGLB distribution has a significant correlation with the length of the dry season. We estimate that the total carbon in forest biomass of the Amazon basin, including the dead and belowground biomass, is 86 Pg C with +/- 20% uncertainty. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Woods Hole Res Ctr, Woods Hole, MA 02543 USA. Inst Nacl Pesquisas Espaciais, BR-12201 Sao Jose Dos Campos, Brazil. RP Saatchi, SS (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM saatchi@congo.jpl.nasa.gov RI Mitchard, Edward/C-6346-2009; SOARES, Joao/D-2576-2014 OI SOARES, Joao/0000-0003-3880-0006 NR 82 TC 272 Z9 293 U1 12 U2 118 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 1354-1013 J9 GLOBAL CHANGE BIOL JI Glob. Change Biol. PD APR PY 2007 VL 13 IS 4 BP 816 EP 837 DI 10.1111/j.1365-2486.2007.01323.x PG 22 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 160KZ UT WOS:000245940800007 ER PT J AU Schnetzer, A Miller, PE Schaffner, RA Stauffer, BA Jones, BH Weisberg, SB DiGiacomo, PM Berelson, WM Caron, DA AF Schnetzer, Astrid Miller, Peter E. Schaffner, Rebecca A. Stauffer, Beth A. Jones, Burton H. Weisberg, Stephen B. DiGiacomo, Paul M. Berelson, William M. Caron, David A. TI Blooms of Pseudo-nitzschia and domoic acid in the San Pedro Channel and Los Angeles harbor areas of the Southern California Bight, 2003-2004 SO HARMFUL ALGAE LA English DT Article DE domoic acid; harmful algal blooms; Los Angeles; Pseudo-nitzschia; Southern California ID DIATOM PSEUDONITZSCHIA-AUSTRALIS; LIONS ZALOPHUS-CALIFORNIANUS; US WEST-COAST; SEA LIONS; BACILLARIOPHYCEAE; ABUNDANCE; TOXICITY; MULTISERIES; LIMITATION; PHOSPHATE AB Abundances of Pseudo-nitzschia spp. and concentrations of particulate domoic acid (DA) were determined in the Southern California Bight (SCB) along the coasts of Los Angeles and Orange Counties during spring and summer of 2003 and 2004. At least 1500 km(2) were affected by a toxic event in May/June of 2003 when some of the highest particulate DA concentrations reported for US coastal waters were measured inside the Los Angeles harbor (12.7 mu g DA L-1). Particulate DA levels were an order of magnitude lower in spring of 2004 (February and March), but DA concentrations per cell at several sampling stations during 2004 exceeded previously reported maxima for natural populations of Pseudo-nitzschia (mean = 24 pg DA cell(-1), range = 0-117 pg DA cell(-1)). Pseudo-nitzschia australis dominated the Pseudo-nitzschia assemblage in spring 2004. Overall, DA-poisoning was implicated in >1400 mammal stranding incidents within the SCB during 2003 and 2004. Ancillary physical and chemical data obtained during our regional surveys in 2004 revealed that Pseudo-nitzschia abundances, particulate DA and cellular DA concentrations were inversely correlated with concentrations of silicic acid, nitrogen and phosphate, and to specific nutrient ratios. Particulate DA was detected in sediment traps deployed at 550 and 800 m depth during spring of 2004 (0.29-7.6 mu g DA (g sediment dry weight)(-1)). The highest DA concentration in the traps was measured within 1 week of dramatic decreases in the abundances of Pseudo-nitzschia in surface waters. To our knowledge these are the deepest sediment trap collections from which DA has been detected. Sinking of the spring Pseudo-nitzschia bloom may constitute a potentially important link between DA production in surface waters and benthic communities in the coastal ocean near Los Angeles. Our study indicates that toxic blooms of Pseudo-nitzschia are a recurring phenomenon along one of the most densely populated coastal stretches of the SCB and that the severity and magnitude of these events can be comparable to or greater than these events in other geographical regions affected by domoic acid. (C) 2006 Elsevier B.V. All rights reserved. C1 Univ So Calif, Dept Biol Sci, Los Angeles, CA 90089 USA. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. So Calif Coastal Res Project, Westminster, CA 92683 USA. CALTECH, NASA Jet Prop Lab, Pasadena, CA 91109 USA. RP Schnetzer, A (reprint author), Univ So Calif, Dept Biol Sci, 3616 Trousdale Pkwy,AHF310, Los Angeles, CA 90089 USA. EM astrids@usc.edu RI Weisberg, Stephen/B-2477-2008; DiGiacomo, Paul/F-5584-2010; Schnetzer, Astrid/F-2527-2010 OI Weisberg, Stephen/0000-0002-0655-9425; DiGiacomo, Paul/0000-0003-4550-1899; NR 54 TC 90 Z9 91 U1 4 U2 24 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1568-9883 J9 HARMFUL ALGAE JI Harmful Algae PD APR PY 2007 VL 6 IS 3 BP 372 EP 387 DI 10.1016/j.hal.2006.11.004 PG 16 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 160BZ UT WOS:000245913100009 ER PT J AU Mosier, KL Sethi, N McCauley, S Khoo, L Orasanu, JM AF Mosier, Kathleen L. Sethi, Nikita McCauley, Shane Khoo, Len Orasanu, Judith M. TI What you don't know can hurt you: Factors impacting diagnosis in the automated cockpit SO HUMAN FACTORS LA English DT Article ID BIAS; JUDGMENT AB Objective: We examined the impact of operational variables on diagnosis and decision-making processes, focusing on information search. Background: Arguably, the "best" decision-making processes in high-technology cockpits would be those that are both correspondent (objectively accurate) and coherent (rationally sound). In the electronic world, coherence in terms of identification and incorporation of all relevant information is both a prerequisite to and a limiting factor for accurate diagnosis and decision making. Method: Regional carrier pilots (N = 93) responded to six scenarios by accessing information to determine a diagnosis and decision. Results: Time pressure, a common operational variable, had a strong negative effect on information search and diagnosis accuracy, and the presence of noncongruent information heightened these negative effects. Unexpectedly, source of initial information (automated or other) did not impact any of the dependent variables. Diagnosis confidence was unrelated to accuracy and was negatively related to amount of information accessed. Conclusion: Results confirm both the need for coherence in diagnostic processes and the difficulty of maintaining it under time pressure. Application: One implication of the results of this study is that pilots in high-technology cockpits must be trained to utilize coherent diagnostic processes as standard operating procedure. Additionally, because thorough information search for diagnosis in an automated environment is essential, automated systems must be designed to foster coherent, and thus accurate, diagnostic processes. C1 San Francisco State Univ, Dept Psychol, San Francisco, CA 94132 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Mosier, KL (reprint author), San Francisco State Univ, Dept Psychol, 1600 Holloway Ave, San Francisco, CA 94132 USA. EM kmosier@sfsu.edu NR 34 TC 10 Z9 10 U1 0 U2 6 PU SAGE PUBLICATIONS INC PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 USA SN 0018-7208 J9 HUM FACTORS JI Hum. Factors PD APR PY 2007 VL 49 IS 2 BP 300 EP 310 DI 10.1518/001872007X312513 PG 11 WC Behavioral Sciences; Engineering, Industrial; Ergonomics; Psychology, Applied; Psychology SC Behavioral Sciences; Engineering; Psychology GA 145ZI UT WOS:000244903900011 PM 17447670 ER PT J AU Heymann, M Degani, A AF Heymann, Michael Degani, Asaf TI Formal analysis and automatic generation of user interfaces: Approach, methodology, and an algorithm SO HUMAN FACTORS LA English DT Article ID SPECIFICATION; DESIGN; MODEL AB Objective: We present a formal approach and methodology for the analysis and generation of user interfaces, with special emphasis on human-automation interaction. Background: A conceptual approach for modeling, analyzing, and verifying the information content of user interfaces is discussed. Methods: The proposed methodology is based on two criteria: First, the interface must be correct - that is, given the interface indications and all related information (user manuals, training material, etc.), the user must be able to successfully perform the specified tasks. Second, the interface and related information must be succinct - that is, the amount of information (mode indications, mode buttons, parameter settings, etc.) presented to the user must be reduced (abstracted) to the minimum necessary. Results: A step-by-step procedure for generating the information content of the interface that is both correct and succinct is presented and then explained and illustrated via two examples. Conclusions: Every user interface is an abstract description of the underlying system. The correspondence between the abstracted information presented to the user and the underlying behavior of a given machine can be analyzed and addressed formally. Applications: The procedure for generating the information content of user interfaces can be automated, and a software tool for its implementation has been developed. Potential application areas include adaptive interface systems and customized/personalized interfaces. C1 NASA, Ames Res Ctr, Div Comp Sci, Mountain View, CA 94035 USA. Technion Israel Inst Technol, IL-31096 Haifa, Israel. RP Degani, A (reprint author), NASA, Ames Res Ctr, Div Comp Sci, Mountain View, CA 94035 USA. EM adegani@mail.arc.nasa.gov NR 38 TC 21 Z9 22 U1 0 U2 3 PU SAGE PUBLICATIONS INC PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 USA SN 0018-7208 J9 HUM FACTORS JI Hum. Factors PD APR PY 2007 VL 49 IS 2 BP 311 EP 330 DI 10.1518/001872007X312522 PG 20 WC Behavioral Sciences; Engineering, Industrial; Ergonomics; Psychology, Applied; Psychology SC Behavioral Sciences; Engineering; Psychology GA 145ZI UT WOS:000244903900012 PM 17447671 ER PT J AU Harmon, JK Slade, MA Butler, BJ Head, JW Rice, MS Campbell, DB AF Harmon, John K. Slade, Martin A. Butler, Bryan J. Head, James W., III Rice, Melissa S. Campbell, Donald B. TI Mercury: Radar images of the equatorial and midlatitude zones SO ICARUS LA English DT Article DE Mercury; Mercury, surface; radar observations ID DELAY-DOPPLER RADAR; SURFACE FEATURES; LONGITUDE RANGE; POLAR ANOMALIES; LUNAR CRATERS; NORTH-POLE; MARS; WAVELENGTH; MARINER-10; REGOLITH AB Radar imaging results for Mercury's non-polar regions are presented. The dual-polarization, delay-Doppler images were obtained from several years of observations with the upgraded Arecibo S-band (lambda 12.6-cm) radar telescope. The images are dominated by radar-bright features associated with fresh impact craters. As was found from earlier Goldstone-VLA and pre-upgrade Arecibo imaging, three of the most prominent crater features are located in the Mariner-unimaged hemisphere. These are: "A;'' an 85-km-diameter crater (348 degrees W, 34 degrees S) whose radar ray system may be the most spectacular in the Solar System; "B," a 95-km-diameter crater (343 degrees W, 58 degrees N) with a very bright halo but less distinct ray system; and "C," an irregular feature with bright ejecta and rays distributed asymmetrically about a 125-km source crater (246 degrees W, 11 degrees N). Due south of "C" lies a "ghost" feature (242 degrees W, 27 degrees S) that resembles "A'' but is much fainter. An even fainter such feature is associated with Bartok Crater. These may be two of the best mercurian examples of large ejecta/ray systems observed in an intermediate state of degradation. Virtually all of the bright rayed craters in the Mariner 10 images show radar rays and/or bright rim rings, with radar rays being less common than optical rays. Radar-bright craters are particularly common in the H-7 quadrangle. Some diffuse radar albedo variations are seen that have no obvious association with impact ejecta. In particular, some smooth plains regions such as the circum-Caloris plains in Tir, Budh, and Sobkou Planitiae and the interiors of Tolstoj and "Skinakas" basins show high depolarized brightness relative to their surroundings, which is the reverse of the mare/highlands contrast seen in lunar radar images. Caloris Basin, on the other hand, appears dark and featureless in the images. (c) 2006 Elsevier Inc. All rights reserved. C1 Arecibo Observ, Natl Astron & Ionosphere Ctr, Arecibo, PR 00612 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. RP Harmon, JK (reprint author), Arecibo Observ, Natl Astron & Ionosphere Ctr, HC3 Box 53995, Arecibo, PR 00612 USA. EM harmon@naic.edu NR 49 TC 29 Z9 29 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD APR PY 2007 VL 187 IS 2 BP 374 EP 405 DI 10.1016/j.icarus.2006.09.026 PG 32 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 149KT UT WOS:000245146500003 ER PT J AU Matson, DL Castillo, JC Lunine, J Johnson, TV AF Matson, Dennis L. Castillo, Julie C. Lunine, Jonathan Johnson, Torrence V. TI Enceladus' plume: Compositional evidence for a hot interior SO ICARUS LA English DT Article DE Enceladus; satellites, composition; prebiotic environments; prebiotic chemistry ID TITANS ATMOSPHERE; HYDROCARBONS; EQUILIBRIUM; ORIGIN; GASES; N-2 AB The combined observations of Saturn's moon Enceladus by the Cassitzi CAPS, INMS and UVIS instruments detected water vapor geysers in which were present molecular nitrogen (N(2)), carbon dioxide (CO(2)), methane (CH(4)), propane (C(3)H(8)), acetylene (C(2)H(2)), and several other species, together with all of the decomposition products Of water. We propose that the presence of N(2) in, the plum,e indicates thermal decomposition of ammonia. and hence high temperatures in the interior of the moon (e.g., 500 to 800 K). Such an environment also appears to be suitable for the production of methane (CH(4)) from carbon monoxide (CO), or carbon dioxide (CO(2)). The presence Of C(2)H(2) and C(3)H(8) strongly suggest that catalytic reactions took place within a very hot environment. The internal environment of Enceladus is inferred to be or have been favorable for aqueous, catalytic chemistry. This pen-nits the synthesis of many complex organic compounds that could be detected in future Cassini observations. (c) 2007 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RP Matson, DL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM dennis.l.matson@jpl.nasa.gov NR 38 TC 85 Z9 85 U1 4 U2 22 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD APR PY 2007 VL 187 IS 2 BP 569 EP 573 DI 10.1016/j.icarus.2006.10.016 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 149KT UT WOS:000245146500018 ER PT J AU Orzechowska, GE Goguen, JD Johnson, PV Tsapin, A Kanik, I AF Orzechowska, Grazyna E. Goguen, Jay D. Johnson, Paul V. Tsapin, Alexandre Kanik, Isik TI Ultraviolet photolysis of amino acids in a 100 K water ice matrix: Application to the outer Solar System bodies SO ICARUS LA English DT Article DE ices; exobiology; organic chemistry; satellites, surfaces; Europa ID EUROPA; SURFACE; ANALOGS; SPACE AB We report the rates of decomposition by ultraviolet (UV) photolysis of four amino acids in millimeter-thick crystalline water ice matrices at 100 K to constrain the survivability of these important organic molecules within ice lying near the surfaces of outer Solar System bodies. We UV-irradiated crystalline ice samples containing known concentrations of the amino acids glycine, aspartic acid, glutamic acid, and phenylalanine, then we measured the surviving concentrations using high performance liquid chromatography (HPLC) with fluorescence detection. From these experiments, we determine photolytic, decomposition rates and half-lives. The half-life varies linearly with the ice thickness for all acids studied here. For example, glycine is the most resistant to photolytic destruction with a half-life of 50, 12, and 3.7 h in 1.6, 0.28, and 0.14 mm thick ices, respectively. We explain this linear variation of half-life with thickness as a consequence of extinction, mostly due to scattering, within these macroscopically thick ice samples. Applied to low latitude surface ice on Jupiter's satellite Europa, this analysis indicates that the concentration of any of these amino acids within the top meter of similar ice will be halved within a similar to 10 year timescale. (c) 2007 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Orzechowska, GE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 183-601, Pasadena, CA 91109 USA. EM grazyna.e.orzechowska@jpl.nasa.gov RI Johnson, Paul/D-4001-2009 OI Johnson, Paul/0000-0002-0186-8456 NR 32 TC 18 Z9 18 U1 1 U2 8 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD APR PY 2007 VL 187 IS 2 BP 584 EP 591 DI 10.1016/j.icarus.2006.10.018 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 149KT UT WOS:000245146500020 ER PT J AU Chaban, GM Bernstein, M Cruikshank, DP AF Chaban, Galina M. Bernstein, Max Cruikshank, Dale P. TI Carbon dioxide on planetary bodies: Theoretical and experimental studies of molecular complexes SO ICARUS LA English DT Article DE ices; infrared observations; Spectroscopy; Jupiter, satellites; Saturn, satellites; satellites, surfaces ID SELF-CONSISTENT-FIELD; ANHARMONIC VIBRATIONAL SPECTROSCOPY; AB-INITIO; BASIS-SETS; GALILEAN SATELLITES; WAVE-FUNCTIONS; WATER; CO2; HYDROGEN; SURFACE AB An absorption band at similar to 4.26 mu m wavelength attributed to the asymmetric stretching mode of C-O in CO(2) has been found on two satellites of Jupiter and several satellites of Saturn. The wavelength of pure CO(2) ice determined in the laboratory is 4.2675 mu m, indicating that the CO(2) on the satellites occurs either trapped in a host material, or in a chemical or physical complex with other materials, resulting in a blue shift of the wavelength of the band. In frequency units, the shifts in the satellite spectra range from 3.7 to 11.3 cm(-1). We have performed A initio quantum chemical calculations Of CO(2) molecules chemically complexed with one, two, and more H(2)O molecules and molecules of CH(3)OH to explore the possibility that the blue shift of the band is caused by chemical complexing Of CO(2) with other volatile materials. Our computations of the harmonic and anharmonic vibrational frequencies using high levels of theory show a frequency shift to the blue by 5 cm(-1) from pure CO(2) to CO-H(2)O, and an additional 5 cm(-1) from CO(2)-H(2)O to CO(2)-2H(2)O. Complexing with more than two H(2)O molecules does not increase the blue shift. Complexes Of CO(2) with one molecule of CH(3)OH and with one CH(3)OH plus one H(2)O molecule produce smaller shifts than the CO(2)-2H(2)O complex. Laboratory studies Of CO(2):H(2)O in a solid N(2) matrix also show a blue shift of the asymmetric stretching mode. Published by Elsevier Inc. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Chaban, GM (reprint author), NASA, Ames Res Ctr, Mail Stop T27B-1, Moffett Field, CA 94035 USA. EM gchaban@mail.arc.nasa.gov; dale.p.cruikshank@nasa.gov NR 39 TC 20 Z9 20 U1 1 U2 8 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD APR PY 2007 VL 187 IS 2 BP 592 EP 599 DI 10.1016/j.icarus.2006.10.010 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 149KT UT WOS:000245146500021 ER PT J AU Tedesco, M Miller, J AF Tedesco, M. Miller, J. TI Northern hemisphere snow-covered area mapping: Optical versus active and passive microwave data SO IEEE GEOSCIENCE AND REMOTE SENSING LETTERS LA English DT Article DE hydrology; remote sensing; snow ID WATER EQUIVALENT; RETRIEVAL; DEPTH; SSM/I AB Spaceborne passive microwave data have been available for the past 27 years, and have supported the development of several algorithms for the retrieval of snow water equivalent and snow depth that, in turn, can be used for mapping snow-covered areas. In contrast, only recently has the application of spaceborne active microwave instruments been investigated for remote sensing of snow on a global scale. This raises the question of whether a technique combining active and passive microwave data can improve the mapping of snow parameters with respect to techniques based solely on passive data. In this letter, we report results concerning the mapping of snow-covered area (SCA) in the Northern Hemisphere between the years 2000 and 2004 derived from the combination of the brightness temperatures at 19.35 and 37 GHz measured by the Special Sensor Microwave Imager Radiometer with backscatter coefficients at 13.4 GHz measured by the NASA's QuickSCAT.SCA derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) is used as a reference to evaluate the performance of the microwave-based techniques and their combination. Results show that, generally, the technique using passive data provides better agreement with MODIS SCA than the technique using only scatterometer data. However, the results,when both datasets are used show considerable improvement, demonstrating the potential benefits of a multisensor approach. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Baltimore, MD 21250 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP Tedesco, M (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Tedesco, Marco/F-7986-2015 NR 19 TC 5 Z9 5 U1 4 U2 9 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1545-598X EI 1558-0571 J9 IEEE GEOSCI REMOTE S JI IEEE Geosci. Remote Sens. Lett. PD APR PY 2007 VL 4 IS 2 BP 221 EP 225 DI 10.1109/LGRS.2006.888842 PG 5 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 161RR UT WOS:000246033900007 ER PT J AU Abbasfar, A Divsalar, D Yao, K AF Abbasfar, Aliazam Divsalar, Dariush Yao, Kung TI Accumulate-repeat-accumulate codes SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article; Proceedings Paper CT IEEE International Symposium on Information Theory CY JUN 27-JUL 02, 2004 CL Chicago, IL SP IEEE, IEEE Informat Theory Soc, Motorola Labs, Qualcomm, Broadcom, IBM Res, Texas Instruments, Microsoft, DARPA, NSF, ONR, Dept Navy Sci & Technol, Flarion, Caltech, Lee Ctr Adv Network DE error bounds; graphs; low-density parity-check (LDPC) codes; thresholds; turbo-like codes; weight distribution ID PARITY-CHECK CODES; SHANNON LIMIT; DESIGN; PERFORMANCE; CAPACITY; GRAPHS AB In this paper, we propose an innovative channel coding scheme called accumulate-repeat-accumulate (ARA) codes. This class of codes can be viewed as serial turbo-like codes or as a subclass of low-density parity check (LDPC) codes, and they have a projected graph or protograph representation; this allows for high-speed iterative decoding implementation using belief propagation. An ARA code can be viewed as precoded repeat accumulate (RA) code with puncturing or as precoded irregular repeat accumulate (IRA) code, where simply an accumulator is chosen as the precoder. The amount of performance improvement due to the precoder will be called precoding gain. Using density evolution on their associated protographs, we find some rate-1/2 ARA codes, with a maximum variable node degree of 5 for which a minimum bit SNR as low as 0.08 dB from channel capacity threshold is achieved as the block size goes to infinity. Such a low threshold cannot be achieved by RA, IRA, or unstructured irregular LDPC codes with the same constraint on the maximum variable node degree. Furthermore, by puncturing the inner accumulator, we can construct families of higher rate ARA codes with thresholds that stay close to their respective channel capacity thresholds uniformly. Iterative decoding simulation results are provided and compared with turbo codes. In addition to iterative decoding analysis, we analyzed the performance of ARA codes with maximum-likelihood (ML) decoding. By obtaining the weight distribution of these codes and through existing tightest bounds we have shown that the ML SNR threshold of ARA codes also approaches very closely to that of random codes. These codes have better interleaving gain than turbo codes. C1 Rambus Inc, Los Altos, CA 94022 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA. RP Abbasfar, A (reprint author), Rambus Inc, Los Altos, CA 94022 USA. EM aliazam@rambus.com; Dariush.Divsalar@jpl.nasa.gov; yao@ee.ucla.edu NR 27 TC 86 Z9 95 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0090-6778 J9 IEEE T COMMUN JI IEEE Trans. Commun. PD APR PY 2007 VL 55 IS 4 BP 692 EP 702 DI 10.1109/TCOMM.2007.894109 PG 11 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 161RV UT WOS:000246034300010 ER PT J AU Dunne, SC Entekhabi, D Njoku, EG AF Dunne, Susan C. Entekhabi, Dara Njoku, Eni G. TI Impact of multiresolution active and passive microwave measurements on soil moisture estimation using the ensemble Kalman smoother SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE data assimilation; ensemble Kalman filter; ensemble Kalman smoother; hydrology; land surface hydrology; microwave remote sensing; reanalysis; soil moisture ID DATA ASSIMILATION; PRECIPITATION; RADIOMETER; MODEL AB An observing system simulation experiment is developed to test tradeoffs in resolution and accuracy for soil moisture estimation using active and passive L-band remote sensing. Concepts for combined radar and radiometer missions include designs that will provide multiresolution measurements. In this paper, the scientific impacts of instrument performance are analyzed to determine the measurement requirements for the mission concept. The ensemble Kalman smoother (EnKS) is used to merge these multiresolution observations with modeled soil moisture from a land surface model to estimate surface and subsurface soil moisture at 6-km resolution. The model used for assimilation is different from that used to generate "truth." Consequently, this experiment simulates how data assimilation, performs in real applications when the model is not a perfect representation of reality. The EnKS is an extension of the ensemble Kalman filter (EnKF) in which observations are used to update states at previous times. Previous work demonstrated that it provides a computationally inexpensive means to improve the results from the EnKF, and that the limited memory in soil moisture can be exploited by employing it as a fixed lag smoother. Here, it is shown that the EnKS can be used in large problems with spatially distributed state vectors and spatially distributed multiresolution observations. The EnKS-based data assimilation framework is used to study the synergy between passive and active observations that have different resolutions and measurement error distributions. The extent to which the design parameters of the EnKS vary depending on the combination of observations assimilated is investigated. C1 Univ Coll Dublin, Meteorol & Climate Ctr, Dublin 4, Ireland. MIT, Dept Civil & Environm Engn, Cambridge, MA 02139 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dunne, SC (reprint author), Univ Coll Dublin, Meteorol & Climate Ctr, Dublin 4, Ireland. EM susan.dunne@ucd.ie; eni.g.njoku@jpl.nasa.gov RI Steele-Dunne, Susan/E-2360-2011 NR 31 TC 23 Z9 24 U1 1 U2 11 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD APR PY 2007 VL 45 IS 4 BP 1016 EP 1028 DI 10.1109/TGRS.2006.890561 PG 13 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 155GP UT WOS:000245566200021 ER PT J AU Vant-Hull, B Marshak, A Remer, LA Li, ZQ AF Vant-Hull, Brian Marshak, Alexander Remer, Lorraine A. Li, Zhanqing TI The effects of scattering angle and cumulus cloud geometry on satellite retrievals of cloud droplet effective radius SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE clouds; remote sensing; terrestrial atmosphere ID OPTICAL-THICKNESS; MODIS; AEROSOL; PRODUCTS AB The effect of scattering angle on Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals of cloud drop effective radius is studied using ensembles of cumulus clouds with varying sun-satellite scattering geometries. The results are interpreted as shadowing and illumination effects. When 3-D clouds are viewed near the backscatter geometry, well-illuminated cloud surfaces are seen, and the retrievals based on plane-parallel geometry underestimate the effective radius. The reverse is true when the satellite is far from the backscatter position, and the shadowed portions of clouds are observed. The shadowing geometry produces a larger bias than the illuminated geometry. These differences between the shadowed and the illuminated ensembles decrease toward zero as the clouds become shallower. Removing the edge pixels based on 1-km-scale geometry partially reduces biases due to the 3-D effects and surface contamination. Recommendations are provided for reducing the 3-D cloud effects using current satellite retrieval algorithms. C1 Univ Maryland, Dept Atmospher & Ocean Sci, College Pk, MD 20741 USA. NASA, Goddard Climate & Radiat Branch, Greenbelt, MD 20771 USA. Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20741 USA. RP Vant-Hull, B (reprint author), Univ Maryland, Dept Atmospher & Ocean Sci, College Pk, MD 20741 USA. EM brianvh@atmos.umd.edu; marshak@climate.gsfc.nasa.gov; lorraine.a.remer@nasa.gov; zli@atmos.umd.edu RI Marshak, Alexander/D-5671-2012; Li, Zhanqing/F-4424-2010 OI Li, Zhanqing/0000-0001-6737-382X NR 22 TC 17 Z9 17 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD APR PY 2007 VL 45 IS 4 BP 1039 EP 1045 DI 10.1109/TGRS.2006.890416 PG 7 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 155GP UT WOS:000245566200023 ER PT J AU Ting, DZY Chang, YC Bandara, SV Hill, CJ Gunapala, SD AF Ting, D. Z.-Y. Chang, Y.-C. Bandara, S. V. Hill, C. J. Gunapala, S. D. TI Band structure and impurity effects on optical properties of quantum well and quantum dot infrared photodetectors SO INFRARED PHYSICS & TECHNOLOGY LA English DT Article DE infrared; quantum well; quantum dot; QWIP; QDIP; discrete dopant effect ID COUPLED-WAVE ANALYSIS; INTERSUBBAND TRANSITIONS; IMPLEMENTATION; GRATINGS AB We examined theoretically band structure and discrete dopant effects in the quantum well infrared photodetector (QWIP) and the quantum dot infrared photodetector (QDIP). We find that in QWIPs discrete dopant effects can induce long wavelength infrared absorption through impurity assisted intra-subband optical transitions. In QDIPs, we find that a strategically placed dopant atom in a quantum dot can easily destroy the symmetry and modify the selection rule. This mechanism could be partially responsible for normal incidence absorption observed in low-aspect-ratio quantum dots. (c) 2006 Elsevier B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. RP Ting, DZY (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM David.Z.Ting@jpl.nasa.gov RI Chang, Yia-Chung/F-4239-2011 NR 10 TC 12 Z9 12 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1350-4495 J9 INFRARED PHYS TECHN JI Infrared Phys. Technol. PD APR PY 2007 VL 50 IS 2-3 BP 136 EP 141 DI 10.1016/j.infrared.2006.10.031 PG 6 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 169ND UT WOS:000246598000009 ER PT J AU Gunapala, SD Bandara, SV Hill, CJ Ting, DZ Liu, JK Rafol, SB Blazejewski, ER Mumolo, JM Keo, SA Krishna, S Chang, YC Shott, CA AF Gunapala, S. D. Bandara, S. V. Hill, C. J. Ting, D. Z. Liu, J. K. Rafol, S. B. Blazejewski, E. R. Mumolo, J. M. Keo, S. A. Krishna, S. Chang, Y.-C. Shott, C. A. TI Demonstration of 640x512 pixels long-wavelength infrared (LWIR) quantum dot infrared photodetector (QDIP) imaging focal plane array SO INFRARED PHYSICS & TECHNOLOGY LA English DT Article ID TEMPERATURE; DETECTIVITY; RESPONSIVITY AB We have exploited the artificial atom-like properties of epitaxially grown self-assembled quantum dots (QDs) for the development of high operating temperature long wavelength infrared (LWIR) focal plane arrays (FPAs). QD infrared photodetectors (QDIPs) are expected to outperform quantum well infrared detectors (QWIPs) and are expected to offer significant advantages over II-VI material based FPAs. We have used molecular beam epitaxy (MBE) technology to grow multi-layer LWIR dot-in-a-well (DWELL) structures based on the InAs/InGaAs/GaAs material system. This hybrid quantum dot/quantum well device offers additional control in wavelength tuning via control of dot-size and/or quantum well sizes. DWELL QDIPs were also experimentally shown to absorb both 45 degrees and normally incident light. Thus we have employed a reflection grating structure to further enhance the quantum efficiency. The most recent devices exhibit peak responsivity out to 8.1 mu m. Peak detectivity of the 8.1 mu m devices has reached similar to 1 x 10(10) Jones at 77 K. Furthermore, we have fabricated the first long-wavelength 640 x 512 pixels QDIP imaging FPA. This QDIP FPA has produced excellent infrared imagery with noise equivalent temperature difference of 40 mK at 60 K operating temperature. (c) 2006 Elsevier B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Infravis Syst, Altadena, CA 91001 USA. Univ New Mexico, Albuquerque, NM 87106 USA. FLIR Syst Inc, Indigo Operat, Goleta, CA 93117 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. RP Gunapala, SD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM sarath.d.gunapala@jpl.nasa.gov RI Krishna, Sanjay /C-5766-2009; Chang, Yia-Chung/F-4239-2011 NR 16 TC 24 Z9 31 U1 2 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1350-4495 J9 INFRARED PHYS TECHN JI Infrared Phys. Technol. PD APR PY 2007 VL 50 IS 2-3 BP 149 EP 155 DI 10.1016/j.infrared.2006.10.004 PG 7 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 169ND UT WOS:000246598000011 ER PT J AU Hill, CJ Li, JV Mumolo, JM Gunapala, SD AF Hill, Cory J. Li, Jian V. Mumolo, Jason M. Gunapala, Sarath D. TI MBE grown type-II MWIR and LWIR superlattice photodiodes SO INFRARED PHYSICS & TECHNOLOGY LA English DT Article DE molecular beam epitaxy; superlattices; infrared detectors; infrared photodiodes; chemical passivation ID INFRARED DETECTORS AB We report on the status of GaSb/InAs type-II superlattice diodes grown and fabricated at the Jet Propulsion Laboratory designed for infrared absorption 2-5 mu m and 8-12 mu m bands. Recent LWIR devices have produced detectivities as high as 8 x 10(10) Jones with a differential resistance-area product greater than 6 Ohm cm(2) at 80 K with a long wavelength cutoff of approximately 12 mu m. The measured internal quantum efficiency of these front-side illuminated devices is close to 30% in the 10-11 mu m range. MWIR devices have produced detectivities as high as 8 x 10(13) Jones with a differential resistance-area product greater than 3 x 10(7) Ohm cm(2) at 80 K with a long wavelength cutoff of approximately 3.7 mu m. The measured internal quantum efficiency of these front-side illuminated MWIR devices is close to 40% in the 2-3 mu m range at low temperature and increases to over 60% near room temperature. (c) 2006 Published by Elsevier B.V. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hill, CJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM cory.j.hill@jpl.nasa.gov RI Li, Jian/B-1627-2016 NR 12 TC 19 Z9 20 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1350-4495 J9 INFRARED PHYS TECHN JI Infrared Phys. Technol. PD APR PY 2007 VL 50 IS 2-3 BP 187 EP 190 DI 10.1016/j.infrared.2006.10.033 PG 4 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 169ND UT WOS:000246598000018 ER PT J AU Bandara, SV Gunapala, SD Ting, DZ Liu, JK Hill, CJ Mumolo, JM Keo, S AF Bandara, S. V. Gunapala, S. D. Ting, D. Z. Liu, J. K. Hill, C. J. Mumolo, J. M. Keo, S. TI Monolithically integrated near-infrared and mid-infrared detector array for spectral imaging SO INFRARED PHYSICS & TECHNOLOGY LA English DT Article DE infrared imaging; quantum well; multicolor; spectrometer ID FOCAL-PLANE ARRAY; PHOTODETECTORS AB A multi-band focal plane array sensitive in near-infrared (near-IR) and mid-wavelength infrared (MWIR) is been developed by monolithically integrating a near-infrared (1-1.5 mu m) p-i-n photodiode with a mid-infrared (3-5 mu m) QWIP. This multiband detector involves both intersubband and interband transitions in III-V semiconductor layer structures. Each detector stack absorbs photons within the specified wavelength band, while allowing the transmission of photons in other spectral bands, thus efficiently permitting multiband detection. Monolithically grown material characterization data and individual detector test results ensure the high quality of material suitable for near-infrared/QWIP dual-band focal plane array. (c) 2006 Elsevier B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bandara, SV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM sumith.v.bandara@jpl.nasa.gov NR 15 TC 7 Z9 8 U1 2 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1350-4495 J9 INFRARED PHYS TECHN JI Infrared Phys. Technol. PD APR PY 2007 VL 50 IS 2-3 BP 211 EP 216 DI 10.1016/j.infrared.2006.10.030 PG 6 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 169ND UT WOS:000246598000023 ER PT J AU Gunapala, SD Bandara, SV Liu, JK Mumolo, JM Hill, CJ Rafol, SB Salazar, D Woolaway, J Levan, PD Tidrow, MZ AF Gunapala, S. D. Bandara, S. V. Liu, J. K. Mumolo, J. M. Hill, C. J. Rafol, S. B. Salazar, D. Woolaway, J. LeVan, P. D. Tidrow, M. Z. TI Towards dualband megapixel QWIP focal plane arrays SO INFRARED PHYSICS & TECHNOLOGY LA English DT Article DE infrared detectors; quantum wells; QWIP; dualband; two-color; multi-band; infrared imaging; focal plane arrays ID WELL INFRARED DETECTORS; NARROW-BAND; BROAD-BAND; CAMERA AB Mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) 1024 x 1024 pixel quantum well infrared photodetector (QWIP) focal planes have been demonstrated with excellent imaging performance. The MWIR QWIP detector array has demonstrated a noise equivalent differential temperature (NE Delta T) of 17 mK at a 95 K operating temperature with f/2.5 optics at 300 K background and the LWIR detector array has demonstrated a NE Delta T of 13 mK at a 70 K operating temperature with the same optical and background conditions as the MWIR detector array after the subtraction of system noise. Both MWIR and LWIR focal planes have shown background limited performance (BLIP) at 90 K and 70 K operating temperatures respectively, with similar optical and background conditions. In addition, we have demonstrated MWIR and LWIR pixel co-registered simultaneously readable dualband QWIP focal plane arrays. In this paper, we will discuss the performance in terms of quantum efficiency, NE Delta T, uniformity, operability, and modulation transfer functions of the 1024 x 1024 pixel arrays and the progress of dualband QWIP focal plane array development work. (c) 2006 Elsevier B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Infravis Syst, Altadena, CA 91001 USA. FLIR Syst Inc, Indigo Operat, Goleta, CA 93117 USA. USAF, Res Lab, Kirtland AFB, NM 87117 USA. Missile Def Agcy AS, Washington, DC 20301 USA. RP Gunapala, SD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM sarath.d.gunapala@jpl.nasa.gov NR 20 TC 28 Z9 29 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1350-4495 J9 INFRARED PHYS TECHN JI Infrared Phys. Technol. PD APR PY 2007 VL 50 IS 2-3 BP 217 EP 226 DI 10.1016/j.infrared.2006.10.005 PG 10 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 169ND UT WOS:000246598000024 ER PT J AU Jhabvala, M Choi, KK Monroy, C La, A AF Jhabvala, M. Choi, K. K. Monroy, C. La, A. TI Development of a 1K x 1K, 8-12 mu m QWIP array SO INFRARED PHYSICS & TECHNOLOGY LA English DT Article ID WELL INFRARED PHOTODETECTORS AB In the on-going evolution of GaAs quantum well infrared photodetectors (QWIPs) we have developed a 1024 X 1024 (1K x 1K), 8-12 mu m infrared focal plane array (FPA). This 1 megapixel detector array is a hybrid using an L3/Cincinnati Electronics silicon readout integrated circuit (ROIC) bump bonded to a GaAs QWIP array fabricated jointly by engineers at the Goddard Space Flight Center (GSFC) and the Army Research Laboratory (ARL). We have integrated the 1K x 1K array into an SE-IR based imaging camera system and performed tests over the 50-80 K temperature range achieving BLIP performance at an operating temperature of 57 K. The GaAs array is relatively easy to fabricate once the superlattice structure of the quantum wells has been defined and grown. The overall arrays costs are currently dominated by the costs associated with the silicon readout since the GaAs array fabrication is based on high yield, well-established GaAs processing capabilities. One of the advantages of GaAs QWIP technology is the ability to fabricate arrays in a fashion similar to and compatible with silicon IC technology. The designer's ability to easily select the spectral response of the material from 3 mu m to beyond 15 mu m is the result of the success of band-gap engineering and the Army Research Lab is a leader in this area. In this paper we will present the first results of our 1K x 1K QWIP array development including fabrication methodology, test data and imaging capabilities. (c) 2006 Elsevier B.V. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USA, Res Lab, Adelphi, MD 20783 USA. RP Jhabvala, M (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM murzy.jhabvala@gsfc.nasa.gov RI Choi, Kwong-Kit/K-9205-2013 NR 14 TC 11 Z9 16 U1 2 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1350-4495 J9 INFRARED PHYS TECHN JI Infrared Phys. Technol. PD APR PY 2007 VL 50 IS 2-3 BP 234 EP 239 DI 10.1016/j.infrared.2006.10.029 PG 6 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 169ND UT WOS:000246598000026 ER PT J AU Moissl, C Hosoya, N Bruckner, J Stuecker, T Roman, M Venkateswaran, K AF Moissl, Christine Hosoya, Naofumi Bruckner, James Stuecker, Tara Roman, Monsi Venkateswaran, Kasthuri TI Molecular microbial community structure of the Regenerative Enclosed Life Support Module Simulator air system SO INTERNATIONAL JOURNAL OF ASTROBIOLOGY LA English DT Article DE clean room; bioaerosol; REMS; 16S rDNA; microbial community; ISS AB The Regenerative Enclosed Life Support Module Simulator (REMS) was designed to simulate the conditions aboard the International Space Station (ISS). This unique terrestrial, encapsulated environment for humans and their associated organisms allowed investigations into the microbial communities within an enclosed habitat system, primarily with respect to diversity, phylogeny and the possible impact on human health. To assess time- and/or condition-dependent changes in microbial diversity within REMS, a total of 27 air samples were collected during three consecutive months. The microbial burden and diversity were elucidated using culture-dependent and culture-independent molecular methods. The results indicate that during controlled conditions the total microbial burden detected by culture-dependent techniques (below a detectable level to 10(2) cells m(-3) of air) and intracellular ATP assay was significantly low (10(2)-10(3) cells m(-3) of air), but increased during the uncontrolled post-operation phase (similar to 10(4) cells m(-3) of air). Only Gram-positive and alpha-proteobacteria grew under tested culture conditions, with a predominant occurrence of Methylobacterium radiotolerans, and Sphingomonas yanoikuyae. Direct DNA extraction and 16S rDNA sequencing methodology revealed a broader diversity of microbes present in the REMS air (51 species). Unlike culture-dependent analysis, both Gram-positive and proteobacteria were equally represented, while members of a few proteobaterial groups dominated (Rhodopseudomonas, Sphingomonas, Acidovorax, Ralstonia, Acinetobacter, Pseudomonas, and Psychrobacter). Although the presence of several opportunistic pathogens warrants further investigation, the results demonstrated that routine maintenance such as controlling the humidity, crew's daily cleaning, and air filtration were effective in reducing the microbial burden in the REMS. C1 [Moissl, Christine; Hosoya, Naofumi; Bruckner, James; Stuecker, Tara; Venkateswaran, Kasthuri] CALTECH, Jet Prop Lab, Biotechnol & Planetary Protect Grp, Pasadena, CA 91109 USA. [Roman, Monsi] NASA, George C Marshall Space Flight Ctr, ECLS Design & Dev Branch, Huntsville, AL 35812 USA. RP Moissl, C (reprint author), CALTECH, Jet Prop Lab, Biotechnol & Planetary Protect Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM kjvenkat@jpl.nasa.gov RI Moissl-Eichinger, Christine/A-6682-2015 OI Moissl-Eichinger, Christine/0000-0001-6755-6263 FU National Aeronautics and Space Administration FX The authors thank D. Newcombe, S. Osman for technical assistance, and D. Jan for continued managerial support. The research described in this publication was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. NR 58 TC 15 Z9 15 U1 1 U2 6 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 1473-5504 J9 INT J ASTROBIOL JI Int. J. Astrobiol. PD APR PY 2007 VL 6 IS 2 BP 131 EP 145 DI 10.1017/S1473550406003533 PG 15 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA V12SD UT WOS:000207618000005 ER PT J AU Canelon, JI Provence, RS Shieh, LS Liu, CR AF Canelon, Jose I. Provence, Robert S. Shieh, Leang S. Liu, Ce R. TI A simple recursive method for stationary receiver position estimation using GPS difference measurements SO ISA TRANSACTIONS LA English DT Article DE GPS; optimal linear model; pseudorange; recursive estimation AB This paper presents a simple recursive method to estimate the position of a stationary receiver using the difference of Global Positioning System (GPS) pseudorange measurements. In contrast to conventional Differential GPS (DGPS), the proposed simple method uses the difference of pseudorange measurements corresponding to a single receiver itself without requiring a fixed station with known location. The use of difference measurements reduces the effects of the various noise terms involved in pseudorange measurements. According to the proposed method, the position of the receiver is estimated recursively using an optimal linear approximation of the pseudorange nonlinear equations. The effectiveness of the proposed method is demonstrated on the estimation of the position of a stationary receiver, and its performance is compared to the performance of a classical approach. The results show that the proposed method outperforms the classical approach. (c) 2007, ISA. Published by Elsevier Ltd. All rights reserved. C1 [Canelon, Jose I.] Univ Zulia, Sch Elect Engn, Maracaibo 4011, Zulia, Venezuela. [Provence, Robert S.] NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. [Shieh, Leang S.; Liu, Ce R.] Univ Houston, Dept Elect & Comp Engn, Houston, TX 77204 USA. RP Canelon, JI (reprint author), Univ Zulia, Sch Elect Engn, Maracaibo 4011, Zulia, Venezuela. EM jcanelon@luz.edu.ve; robert.s.provence@nasa.gov; lshieh@uh.edu; cliu@uh.edu NR 9 TC 1 Z9 2 U1 0 U2 4 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0019-0578 J9 ISA T JI ISA Trans. PD APR PY 2007 VL 46 IS 2 BP 147 EP 155 DI 10.1016/j.isatra.2006.09.003 PG 9 WC Automation & Control Systems; Engineering, Multidisciplinary; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA 269PR UT WOS:000253661900002 PM 17362953 ER PT J AU Peng, K Hombergera, L Nguyena, CV Sopory, U AF Peng, Kern Hombergera, Lee Nguyena, Cattien V. Sopory, Umesh TI Processing of dispersed and aligned multi-walled carbon nanotubes in polyvinylidene fluoride SO JOURNAL OF ADVANCED MATERIALS LA English DT Article ID MORPHOLOGICAL CHARACTERIZATION; POLY(VINYLIDENE FLUORIDE); POLYIMIDE COMPOSITES; OPTICAL-PROPERTIES; POLYMER-MATRIX; SINGLE; BLENDS; FILMS AB Carbon nanotube (CNT)/polymer composites have many potential applications, however, because of the inherently strong affinity of CNT to themselves, uniform dispersion of CNT in polymer nanocomposites has been extremely challenging to achieve. This study reports a sequence of processing steps to enhance mechanical properties of CNT polyvinylidene fluoride (PVDF) composites. A combination of mechanical extrusion, chemical dispersion, and thermal treatment processes are demonstrated for improving both dispersion and uniaxial alignment of CNT in PVDF Optimal processing conditions are demonstrated in which 10 wt% CNT in PVDF composites showed a 77% improvement in tensile strength, one of the highest values for mechanical enhancement for CNT polymer composites to date. C1 Santa Clara Univ, Dept Mech Engn, Santa Clara, CA 95053 USA. BAE Syst, Emerging Technol, Santa Clara, CA USA. ELORET Corp, NASA, Ames Ctr Nanotechnol, Moffett Field, CA USA. ASUK Technol, San Leandro, CA USA. RP Peng, K (reprint author), Santa Clara Univ, Dept Mech Engn, Santa Clara, CA 95053 USA. NR 30 TC 1 Z9 1 U1 1 U2 5 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 USA SN 1070-9789 J9 J ADV MATER-COVINA JI J. Adv. Mater. PD APR PY 2007 VL 39 IS 2 BP 24 EP 31 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 191LU UT WOS:000248133500005 ER PT J AU Gilat, A Goldberg, RK Roberts, GD AF Gilat, Amos Goldberg, Robert K. Roberts, Gary D. TI Strain rate sensitivity of epoxy resin in tensile and shear loading SO JOURNAL OF AEROSPACE ENGINEERING LA English DT Article DE strain rate; epoxy resins; deformation; laminates ID CRACK-TIP FIELDS; THERMOSETTING RESINS; DEFORMATION-BEHAVIOR; COMPRESSION; YIELD AB The mechanical response of E-862 and PR-520 resins is investigated in tensile and shear loadings. At both types of loading the resins are tested at strain rates of about 5 X 10(-5), 2, and 450-700 s(-1). In addition, dynamic shear modulus tests are carried out at various frequencies and temperatures, and tensile stress relaxation tests are conducted at room temperature. The results show that the toughened PR-520 resin can carry higher stresses than the untoughened E-862 resin. Strain rate has a significant effect on the response of both resins. In shear, both resins show a ductile response with maximum stress that is increasing with strain rate. In tension, a ductile response is observed at low strain rate (similar to 5 X 10(-5) s(-1)), and brittle response is observed at the medium and high strain rates (2 and 700 s(-1)). The hydrostatic component of the stress in the tensile tests causes premature failure in the E-862 resin. Localized deformation develops in the PR-520 resin when loaded in shear. An internal state variable constitutive model is proposed for modeling the response of the resins. The model includes a state variable that accounts for the effect of the hydrostatic component of the stress on the deformation. C1 Ohio State Univ, Dept Mech Engn, Columbus, OH 43210 USA. NASA, Glenn Res Ctr, Cleveland, OH USA. RP Gilat, A (reprint author), Ohio State Univ, Dept Mech Engn, 201 W 19th Ave, Columbus, OH 43210 USA. EM gilat.1@osu.edu NR 22 TC 34 Z9 34 U1 1 U2 20 PU ASCE-AMER SOC CIVIL ENGINEERS PI RESTON PA 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA SN 0893-1321 EI 1943-5525 J9 J AEROSPACE ENG JI J. Aerosp. Eng. PD APR PY 2007 VL 20 IS 2 BP 75 EP 89 DI 10.1061/(ASCE)0893-1321(2007)20:2(75) PG 15 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA 148FM UT WOS:000245060000001 ER PT J AU Zeng, X Agui, JH Nakagawa, M AF Zeng, X. Agui, J. H. Nakagawa, M. TI Wave velocities in granular materials under microgravity SO JOURNAL OF AEROSPACE ENGINEERING LA English DT Article DE wave velocity; granular materials; wave measurement ID BENDER ELEMENT TESTS; FREQUENCY RANGE; ELASTIC WAVES; PROPAGATION; G(MAX) AB Velocities of primary (P) and shear (S) waves in granular materials are highly dependent on confining stress. These wave velocities are related to mechanical properties of the materials such as stiffness, density, and stress history. Measurements of the wave velocities using piezoelectric sensors provide scientists and engineers a technique for nonintrusive characterization of those mechanical properties. For aerospace engineering, measuring the wave velocities under microgravity, which simulates low loading and stress conditions, has a number of potential applications. It can help the understanding of the soil mechanics and the development of appropriate materials handling technologies in extraterrestrial environments, which will be crucial to meeting NASA's future space exploration goals. This paper presents the technique and results of experiments conducted at NASA Glenn Research Center using the 2.2 s drop tower. Velocities of P and S waves in three sizes of glass beads and one size of alumina beads were measured under initially dense or loose compaction states. It was found that under microgravity, the wave signals were significantly weaker and the velocities were much slower. The material that makes up the beads has a strong influence on the wave velocities as well. The initial compaction state also has some influence on the wave velocities. C1 Case Western Reserve Univ, Dept Civil Engn, Cleveland, OH 44016 USA. NASA, Glenn Res Ctr, Micrograv Sci Div, Cleveland, OH 44135 USA. Colorado Sch Mines, Dept Min Engn, Golden, CO 80401 USA. RP Zeng, X (reprint author), Case Western Reserve Univ, Dept Civil Engn, Cleveland, OH 44016 USA. NR 17 TC 4 Z9 4 U1 0 U2 6 PU ASCE-AMER SOC CIVIL ENGINEERS PI RESTON PA 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA SN 0893-1321 J9 J AEROSPACE ENG JI J. Aerosp. Eng. PD APR PY 2007 VL 20 IS 2 BP 116 EP 123 DI 10.1061/(ASCE)0893-1321(2007)20:2(116) PG 8 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA 148FM UT WOS:000245060000005 ER PT J AU Baum, BA Yang, P Nasiri, S Heidinger, AK Heymsfield, A Li, J AF Baum, Bryan A. Yang, Ping Nasiri, Shaima Heidinger, Andrew K. Heymsfield, Andrew Li, Jun TI Bulk scattering properties for the remote sensing of ice clouds. Part III: High-resolution spectral models from 100 to 3250 cm(-1) SO JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY LA English DT Article ID TIME-DOMAIN SOLUTION; LIGHT-SCATTERING; INFRARED WAVELENGTHS; RADIATIVE PROPERTIES; OPTICAL-THICKNESS; NATURAL CLOUDS; CIRRUS; CRYSTALS; PARTICLES; ABSORPTION AB This study reports on the development of bulk single-scattering models for ice clouds that are appropriate for use in hyperspectral radiative transfer cloud modeling over the spectral range from 100 to 3250 cm(-1). The models are developed in a manner similar to that recently reported for the Moderate-Resolution Imaging Spectroradiometer (MODIS); therefore these models result in a consistent set of scattering properties from visible to far-infrared wavelengths. The models incorporate a new database of individual ice-particle scattering properties that includes droxtals, 3D bullet rosettes, hexagonal solid and hollow columns, aggregates, and plates. The database provides single-scattering properties for each habit in 45 size bins ranging from 2 to 9500 mu m, and for 49 wavenumbers between 100 and 3250 cm(-1), which is further interpolated to 3151 discrete wavenumbers on the basis of a third-order spline interpolation method. Bulk models are developed by integrating various properties over both particle habit and size distributions. Individual bulk models are developed for 18 effective diameters D-eff, ranging from D-eff = 10 mu m to D-eff = 180 mu m. A total of 1117 particle size distributions are used in the analyses and are taken from analysis of the First International Satellite Cloud Climatology Project Regional Experiment (FIRE)-I, FIRE-II, Atmospheric Radiation Measurement Program intensive operation period (ARM-IOP), Tropical Rainfall Measuring Mission Kwajalein Experiment (TRMM-KWAJEX), and Cirrus Regional Study of Tropical Anvils and Cirrus Layers Florida-Area Cirrus Experiment (CRYSTAL-FACE) data. The models include microphysical and scattering properties such as median mass diameter, effective diameter, single-scattering albedo, asymmetry factor, and scattering phase function. The spectral models are appropriate for applications involving the interpretation of the radiometric measurements of ice clouds acquired by infrared spectrometers such as the Atmospheric Infrared Sounder (AIRS) on the NASA Aqua satellite and the Cross-Track Infrared Sounder (CrIS) on the upcoming National Polar-Orbiting Environmental Satellite System (NPOESS) platforms. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. Texas A&M Univ, College Stn, TX USA. NOAA, NESDIS, Silver Spring, MD USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Cooperat Inst Meteorol Satellite Studies, Madison, WI USA. RP Baum, BA (reprint author), Univ Wisconsin, Ctr Space Sci & Engn, 1225 W Dayton St, Madison, WI 53706 USA. EM bryan.baum@ssec.wisc.edu RI Yang, Ping/B-4590-2011; Baum, Bryan/B-7670-2011; Heymsfield, Andrew/E-7340-2011; Nasiri, Shaima/C-8044-2011; Heidinger, Andrew/F-5591-2010; Li, Jun/H-3579-2015 OI Baum, Bryan/0000-0002-7193-2767; Heidinger, Andrew/0000-0001-7631-109X; Li, Jun/0000-0001-5504-9627 NR 32 TC 40 Z9 41 U1 2 U2 9 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1558-8424 J9 J APPL METEOROL CLIM JI J. Appl. Meteorol. Climatol. PD APR PY 2007 VL 46 IS 4 BP 423 EP 434 DI 10.1175/JAM2473.1 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 161OR UT WOS:000246025400003 ER PT J AU Zhang, BL Pinker, RT Stackhouse, PW AF Zhang, Banglin Pinker, Rachel T. Stackhouse, Paul W., Jr. TI An empirical orthogonal function iteration approach for obtaining homogeneous radiative fluxes from satellite observations SO JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY LA English DT Article ID SEA-SURFACE TEMPERATURE; CLIMATE-RESEARCH; WATER-VAPOR; ISCCP; CLOUD; OCEAN; INTERPOLATION; VALIDATION; PACIFIC; DATASET AB Conventional observations of climate parameters are sparse in space and/or time, and the representativeness of such information needs to be optimized. Observations from satellites provide improved spatial coverage over point observations; however, they pose new challenges for obtaining homogeneous coverage. Surface radiative fluxes, the forcing functions of the hydrologic cycle and biogeophysical processes, are now becoming available from global-scale satellite observations. They are derived from independent satellite platforms and sensors that differ in temporal and spatial resolution and in the size of the footprint from which information is derived. Data gaps, degraded spatial resolution near boundaries of geostationary satellites, and different viewing geometries in areas of satellite overlap could result in biased estimates of radiative fluxes. In this study will be discussed issues related to the sources of inhomogeneity in surface radiative fluxes as derived from satellites, development of an approach to obtain homogeneous datasets, and application of the method to the widely used International Satellite Cloud Climatology Project data that currently serve as a source of information for deriving estimates of surface and top-of-the-atmosphere radiative fluxes. Introduced is an empirical orthogonal function (EOF) iteration scheme for homogenizing the fluxes. The scheme is evaluated in several ways, including comparison of the inferred radiative fluxes with ground observations, both before and after the EOF approach is applied. On the average, the latter reduces the RMS error by about 2 - 3 W m(-2). C1 Univ Maryland, Dept Atmospher & Ocean Sci, College Pk, MD 20742 USA. Sci Applicat Int Corp, Greenbelt, MD USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Pinker, RT (reprint author), Univ Maryland, Dept Atmospher & Ocean Sci, College Pk, MD 20742 USA. EM pinker@atmos.umd.edu RI Pinker, Rachel/F-6565-2010 NR 33 TC 6 Z9 7 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1558-8424 EI 1558-8432 J9 J APPL METEOROL CLIM JI J. Appl. Meteorol. Climatol. PD APR PY 2007 VL 46 IS 4 BP 435 EP 444 DI 10.1175/JAM2478.1 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 161OR UT WOS:000246025400004 ER PT J AU Brown, ST Ruf, CS AF Brown, Shannon T. Ruf, Christopher S. TI Validation and development of melting layer models using constraints by active/passive microwave observations of rain and the wind-roughened ocean surface SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID SIZE DISTRIBUTION; ICE PARTICLES; SEA-SURFACE; PART I; RADAR; PRECIPITATION; HYDROMETEORS; RETRIEVALS; EMISSIVITY; RADIOMETER AB A physically based method is developed to estimate the microphysical structure of the melting layer in stratiform rain using airborne observations by a dual- frequency radar and a 10.7- GHz radiometer. The method employs a nonlinear optimal estimation approach to find two parameters of the gamma drop size distribution ( DSD) at each radar range gate from the Ku/Ka-band reflectivities. The DSD profile is used to determine the atmospheric absorption/ extinction profile, which enables the surface contribution to the measured brightness temperature to be estimated. The surface wind speed is estimated from the surface emissivity by inverting the forward model, which relates the two. Retrievals in stratiform precipitation require a model to describe the thermodynamic and electromagnetic properties of melting hydrometeors. The melting layer can contribute a majority of the total atmospheric absorption, making it a key component for accurate retrievals in stratiform rain. Several melting layer models were evaluated based on their fit to the dual- frequency reflectivity measurements in the melting layer. A candidate model is selected and tuned to match the radar measurements. The melting layer model is then incorporated into the full forward model for the brightness temperature observed by the radiometer. The surface wind speed assumed in the forward model is forced by the radiometer observations. If the actual surface wind speed is known, this approach provides a powerful constraint on the possible melting layer model. A case study is presented from an airborne campaign over areas of precipitation off the coast of Vancouver Island, British Columbia, Canada. The estimated wind speeds are found to be uncorrelated with the reflectivity and their average value is within 1 m s(-1) of that retrieved in a clear area adjacent to the rain. C1 Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. RP Brown, ST (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 168-134, Pasadena, CA 91109 USA. EM shannon.t.brown@jpl.nasa.gov RI Ruf, Christopher/I-9463-2012 NR 44 TC 2 Z9 2 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 EI 1520-0426 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD APR PY 2007 VL 24 IS 4 BP 543 EP 563 DI 10.1175/JTECH1993.1 PG 21 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 157TC UT WOS:000245742900002 ER PT J AU Loeb, NG Kato, S Loukachine, K Manalo-Smith, N Doelling, DR AF Loeb, Norman G. Kato, Seiji Loukachine, Konstantin Manalo-Smith, Natividad Doelling, David R. TI Angular distribution models for top-of-atmosphere radiative flux estimation from the Clouds and the Earth's Radiant Energy System instrument on the Terra satellite. Part II: Validation SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID MEASURING MISSION SATELLITE; BIDIRECTIONAL REFLECTANCE; ZENITH ANGLE; MODIS; ALGORITHM; AEROSOL; INVERSION; METHODOLOGY; DEPENDENCE; SCATTERING AB Errors in top- of- atmosphere ( TOA) radiative fluxes from the Clouds and the Earth's Radiant Energy System ( CERES) instrument due to uncertainties in radiance- to- flux conversion from CERES Terra angular distribution models ( ADMs) are evaluated through a series of consistency tests. These tests show that the overall bias in regional monthly mean shortwave ( SW) TOA flux is less than 0.2Wm(-2) and the regional RMS error ranges from 0.70 to 1.4 W m(-2). In contrast, SW TOA fluxes inferred using theoretical ADMs that assume clouds are plane parallel are overestimated by 3 - 4 W m(-2) and exhibit a strong latitudinal dependence. In the longwave ( LW), the bias error ranges from 0.2 to 0.4 W m(-2) and regional RMS errors remain smaller than 0.7 W m(-2). Global mean albedos derived from ADMs developed during the Earth Radiation Budget Experiment ( ERBE) and applied to CERES measurements show a systematic increase with viewing zenith angle of 4% - 8%, while albedos from the CERES Terra ADMs show a smaller increase of 1% - 2%. The LW fluxes from the ERBE ADMs show a systematic decrease with viewing zenith angle of 2% - 2.4%, whereas fluxes from the CERES Terra ADMs remain within 0.7% - 0.8% at all angles. Based on several months of multiangle CERES along- track data, the SW TOA flux consistency between nadir-and oblique- viewing zenith angles is generally 5% ( < 17 W m(-2)) over land and ocean and 9% ( 26 W m(-2)) in polar regions, and LW TOA flux consistency is approximate 3% ( 7 W m(-2)) over all surfaces. Based on these results and a theoretically derived conversion between TOA flux consistency and TOA flux error, the best estimate of the error in CERES TOA flux due to the radiance- to- flux conversion is 3% ( 10 W m(-2)) in the SW and 1.8% ( 3 - 5 W m(-2)) in the LW. Monthly mean TOA fluxes based on ERBE ADMs are larger than monthly mean TOA fluxes based on CERES Terra ADMs by 1.8 and 1.3 W m(-2) in the SW and LW, respectively. C1 Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. Sci Applicat Int Corp, Hampton, VA USA. Analyt Serv & Mat, Hampton, VA USA. RP Loeb, NG (reprint author), NASA, Langley Res Ctr, MS 420, Hampton, VA 23681 USA. EM n.g.loeb@larc.nasa.gov NR 38 TC 83 Z9 83 U1 1 U2 8 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD APR PY 2007 VL 24 IS 4 BP 564 EP 584 DI 10.1175/JTECH1983.1 PG 21 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 157TC UT WOS:000245742900003 ER PT J AU Evangelista, H Maldonado, J Godoi, RHM Pereira, EB Koch, D Tanizaki-Fonseca, K Van Grieken, R Sampaio, M Setzer, A Alencar, A Goncalves, SC AF Evangelista, H. Maldonado, J. Godoi, R. H. M. Pereira, E. B. Koch, D. Tanizaki-Fonseca, K. Van Grieken, R. Sampaio, M. Setzer, A. Alencar, A. Goncalves, S. C. TI Sources and transport of urban and biomass burning aerosol black carbon at the South-West Atlantic coast SO JOURNAL OF ATMOSPHERIC CHEMISTRY LA English DT Article DE black carbon; South-West Atlantic; Antarctic Peninsula; back trajectories; GCM ID EMISSIONS; RADIATION; CLOUDS; SMOKE AB The total extent of the atmospheric impacts associated to the aerosol black carbon (BC) emissions from South America is not completed described. This work presents results of BC monitored during three scientific expeditions (2002, 2003 and 2004) on board of a Brazilian oceanographic vessel Ary Rongel that covered the South-West Atlantic coast between 22-62 degrees S. This latitudinal band encloses major urban regions of South America and the outflow region of the SACZ (South Atlantic Convergent Zone), which is an important mechanism of advective transport of heat, moisture, minor gases and aerosols from the South America continental land to the Southern Atlantic Ocean. Our results showed that aerosol BC enhanced concentrations from urban/industrial origin can be transported to the South-West Atlantic Ocean due to the migration of sub-polar fronts that frequently reach tropical/subtropical regions. Despite the decrease of aerosol BC concentrations southwards (from similar to 1,200 ng m(-3) at latitude 22 degrees S to similar to 10 ng m(-3) at latitude 62 degrees S), several observed peak events were attributed to regional urban activities. Most of such events could be explained by the use of air mass back trajectories analysis. In addition, a global model simulation is presented (Goddard Institute for Space Studies - GISS GCM BC simulation) to explore the origins of aerosol BC in the South-West Atlantic. The model allowed isolating the biomass emissions from South America and Africa and industrial (non-biomass) pollution from other regions of the globe. This model suggests that the apportionment of about half of the aerosol BC at the South-West Atlantic may derive from South American biomass burning. C1 Univ Estado Rio De Janeiro, LARAMG UERJ, Dept Biophys & Biometry, BR-20550013 Rio De Janeiro, Brazil. Univ Fed Fluminense, Inst Quim, Dept Geoquim, Niteroi, RJ, Brazil. Ctr Univ Positivo UnicenP, Grad Program Environm Management, BR-81280330 Curitiba, Parana, Brazil. Brazilian Natl Space Inst INPE, CPTEC, Ctr Numer Weather Forecast & Climate Studies, BR-12245970 Sao Jose Dos Campos, Brazil. Columbia Univ, Ctr Climate Syst Res, New York, NY USA. NASA, GISS, New York, NY USA. Univ Antwerp, Dept Chem, Micro & Trace Anal Ctr, B-2610 Antwerp, Belgium. Brazilian Natl Space Inst INPE, BR-12245970 Sao Jose Dos Campos, SP, Brazil. RP Van Grieken, R (reprint author), Univ Estado Rio De Janeiro, LARAMG UERJ, Dept Biophys & Biometry, PAvilhao HLC Subsolo R Sao Francisco Xavier 524, BR-20550013 Rio De Janeiro, Brazil. EM heitor@uerj.br; juantsi@yahoo.com.br; ricardo.godoi@unicenp.edu.br; eniobp@cptec.inpe.br; dkoch@giss.nasa.gov; Rene.VanGrieken@ua.ac.be; marcelo.sampaio@dge.inpe.br; asetzer@cptec.inpe.br RI Pereira, Enio/B-3077-2013; Evangelista, Heitor/C-7561-2013 NR 20 TC 10 Z9 14 U1 0 U2 17 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-7764 J9 J ATMOS CHEM JI J. Atmos. Chem. PD APR PY 2007 VL 56 IS 3 BP 225 EP 238 DI 10.1007/s10874-006-9052-8 PG 14 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 148VT UT WOS:000245105900002 ER PT J AU Liang, MTC Bassin, S Dutto, D Braun, W Wong, N Pontello, AM Cooper, DM Arnaud, SB AF Liang, Michael T. C. Bassin, Stanley Dutto, Darren Braun, William Wong, Nathan Pontello, Andria M. Cooper, Dan M. Arnaud, Sara B. TI Bone mineral density and leg muscle strength in young Caucasian, Hispanic, and Asian women SO JOURNAL OF CLINICAL DENSITOMETRY LA English DT Article DE ethnic differences; heel BMD; leg strength; wrist BMD; young women ID POSTMENOPAUSAL WOMEN; PHYSICAL-ACTIVITY; HIP FRACTURE; LIFE-STYLE; BODY-SIZE; MASS; WHITE; PREMENOPAUSAL; OSTEOPOROSIS; JAPANESE AB Differences in bone mineral density (BMD) of ethnically diverse populations are usually attributed to anthropometric characteristics, but may also be due to life style or diet. We studied healthy young sedentary women with Asian (ASN, n = 40), Hispanic (HIS, n = 39), or Caucasian (CAU, n = 36) backgrounds. Body composition and regional BMD were measured by dual-energy X-ray absorptiometry (Hologic) or PIXI (Lunar GE) for the heel and wrist). Leg strength was quantified with a leg press and dietary calcium was estimated with 3-d diet records. CAU were taller than HIS and ASN (p < 0.01). ASN had lower body weights, fat mass, lean body mass, and leg strength than HIS or CAU (p < 0.01). Differences in BMD among groups were not eliminated by adjusting for body weight and height at the arm, trochanter, femoral neck, and total hip where BMD values remained lower in the ASN than in HIS or CAU (p < 0.01). Conversely, adjusted BMD at the wrist was 7.3% higher in ASN and 8.3% higher in HIS and at the heel, 7.3% higher in ASN and 7.0% higher in HIS than in CAU (p < 0.05). Leg strength was a significant predictor of BMD in the hip in CAU (R = 0.53, p = 0.004), in the hip with dietary calcium in ASN (R = 0.65, p = 0.02), and in the heel with height in HIS (R = 0.57, p = 0.03). We conclude that significant factors underlying BMD in ethnically diverse young women vary as a function of ethnicity and include leg strength and dietary calcium as well as anthropometric characteristics. C1 NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. Calif State Polytech Univ Pomona, Pomona, CA 91768 USA. Univ Calif Irvine, Irvine, CA USA. Eastern Oregon Univ, La Grande, OR USA. Shippensburg State Univ, Shippensburg, PA USA. RP Arnaud, SB (reprint author), NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. EM sarnaud@mail.arc.nasa.gov FU NCRR NIH HHS [5 M01 RR00827-29, M01 RR000827, M01 RR000827-29]; NIGMS NIH HHS [5 SO GM053933-06, S06 GM053933, S06 GM053933-06S2] NR 28 TC 10 Z9 10 U1 0 U2 3 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 1094-6950 J9 J CLIN DENSITOM JI J. Clin. Densitom. PD APR-JUN PY 2007 VL 10 IS 2 BP 157 EP 164 DI 10.1016/j.jocd.2006.12.005 PG 8 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 169OI UT WOS:000246601100008 PM 17485032 ER PT J AU Ju, JY Morgan, RJ Creasy, TS Shin, EE AF Ju, Jaehyung Morgan, Roger J. Creasy, Terry S. Shin, E. Eugene TI Transverse cracking of M40J/PMR-II-50 composites under thermal-mechanical loading: Part I - Characterization of main and interaction effects using statistical design of experiments SO JOURNAL OF COMPOSITE MATERIALS LA English DT Article DE design of experiment (DOE); M40J/PMR-II-50 (carbon fiber/ polyimide composites); thermal cycling; microcracks ID CARBON FIBER/EPOXY COMPOSITES; MATRIX CRACKING; CRYOGENIC MICROCRACKING; OPTIMIZATION; PARAMETERS; STRENGTH AB In this study, a novel conduction heating-based thermal cycling apparatus combined with large deflection bending is developed and utilized to identify the critical controlling parameters for microcracking of [90/0](1s), M40J/ PMR-II-50 high modulus carbon fiber/polyimide composite laminate under synergistic environmental conditions. The synergistic test involves four controlling parameters namely, average in-plane mechanical strains (0 and 0.488%), thermal cycling temperature amplitudes (-196-23 degrees C and -196-250 degrees C), number of thermal cycles (1 and 8), and heating rate (1 and 4 degrees C/min). The 2(k) factorial design is used for the four factors to provide their quantitative primary and interaction effects on crack density with a minimum number of experiments. The experimental results indicate that the number of thermal cycles is the primary controlling factor (41%), while the thermal cycling temperature amplitude (25%) or the in-plane strain (22%) is the secondary factor. The number of thermal cycles also exhibits a significant interaction effect on the development of microcracks when it was combined with either the temperature amplitude of thermal cycling (7%) or mechanical in-plane strain (5%). C1 Texas A&M Univ, Dept Mech Engn, College Stn, TX 77843 USA. NASA, Lewis Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Ju, JY (reprint author), Texas A&M Univ, Dept Mech Engn, College Stn, TX 77843 USA. EM jaehyung@tamu.edu NR 35 TC 1 Z9 1 U1 1 U2 9 PU SAGE PUBLICATIONS LTD PI LONDON PA 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND SN 0021-9983 J9 J COMPOS MATER JI J. Compos Mater. PD APR PY 2007 VL 41 IS 8 BP 1009 EP 1031 DI 10.1177/0021998306067259 PG 23 WC Materials Science, Composites SC Materials Science GA 169US UT WOS:000246618200007 ER PT J AU Hogue, MD Mucciolo, ER Calle, CI AF Hogue, Michael D. Mucciolo, Eduardo R. Calle, Carlos I. TI Triboelectric, corona, and induction charging of insulators as a function of pressure SO JOURNAL OF ELECTROSTATICS LA English DT Article DE tribocharging; insulators; corona charging; induction; pressure; atmosphere AB Theoretical and experimental research that was carried out showed that the surface charge on an insulator after triboelectric charging with another insulator is rapidly dissipated with lowered atmospheric pressure. This pressure discharge is consistent with surface ions being evaporated off the surface once their vapor pressure is attained. In this paper, we will report on the results of three different charging techniques (triboelectric, corona, and induction) carried out on selected polymers with varying atmospheric pressure. This data will show that ion exchange between the insulators is the mechanism responsible for most of the surface charge on the polymers. (C) 2006 Elsevier B.V. All rights reserved. C1 NASA, Electrostat & Surface Phys Lab, Kennedy Space Ctr, FL 32899 USA. Univ Cent Florida, Dept Phys, Orlando, FL 32816 USA. RP Hogue, MD (reprint author), NASA, Electrostat & Surface Phys Lab, Kennedy Space Ctr, FL 32899 USA. EM michael.d.hogue@nasa.gov; mucciolo@physics.ucf.edu NR 4 TC 16 Z9 16 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3886 J9 J ELECTROSTAT JI J. Electrost. PD APR PY 2007 VL 65 IS 4 BP 274 EP 279 DI 10.1016/j.elstat.2006.10.003 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA 155UH UT WOS:000245603400012 ER PT J AU Nachtigall, PE Supin, AY Amundin, M Roken, B Moller, T Mooney, TA Taylor, KA Yuen, M AF Nachtigall, Paul E. Supin, Alexander Y. Amundin, Mats Roken, Bengt Moller, Thorsten Mooney, T. Aran Taylor, Kristen A. Yuen, Michelle TI Polar bear Ursus maritimus hearing measured with auditory evoked potentials SO JOURNAL OF EXPERIMENTAL BIOLOGY LA English DT Article DE bear hearing; polar bear; evoked potential ID SEAL PHOCA-HISPIDA; RINGED SEALS; PINNIPEDS AB While there has been recent concern about the effects of sound on marine mammals, including polar bears, there are no data available measuring the hearing of any bear. The in-air hearing of three polar bears was measured using evoked auditory potentials obtained while tone pips were played to three individually anaesthetized bears at the Kolmarden Djurpark. Hearing was tested in half-octave steps from 1 to 22.5 kHz. Measurements were not obtainable at 1 kHz and best sensitivity was found in the range from 11.2-22.5 kHz. Considering the tone pips were short and background noise measurements were available, absolute measurements were estimated based on an assumed mammalian integration time of 300 ms. These data show sensitive hearing in the polar bear over a wide frequency range and should cause those concerned with the introduction of anthropogenic noise into the polar bear's environment to operate with caution. C1 Univ Hawaii, Hawaii Inst Marine Biol, Marine Mammal Res Program, Honolulu, HI 96822 USA. Russian Acad Sci, Inst Ecol & Evolut, Moscow, Russia. Kolmarden Djurpark, Kolmarden, Sweden. Pacific Isl Reg Off, Natl Marine Fisheries Serv, Honolulu, HI USA. RP Nachtigall, PE (reprint author), Univ Hawaii, Hawaii Inst Marine Biol, Marine Mammal Res Program, Honolulu, HI 96822 USA. EM nachtiga@hawaii.edu NR 33 TC 19 Z9 19 U1 3 U2 13 PU COMPANY OF BIOLOGISTS LTD PI CAMBRIDGE PA BIDDER BUILDING CAMBRIDGE COMMERCIAL PARK COWLEY RD, CAMBRIDGE CB4 4DL, CAMBS, ENGLAND SN 0022-0949 J9 J EXP BIOL JI J. Exp. Biol. PD APR 1 PY 2007 VL 210 IS 7 BP 1116 EP 1122 DI 10.1242/jeb.02734 PG 7 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 147WX UT WOS:000245036500011 PM 17371910 ER PT J AU Kubitschek, DG Mastrodemos, N Werner, RA Synnott, SP Bhaskaran, S Riedel, JE Kennedy, BM Null, GW Vaughan, AT AF Kubitschek, Daniel G. Mastrodemos, Nickolaos Werner, Robert A. Synnott, Stephen P. Bhaskaran, Shyam Riedel, Joseph E. Kennedy, Brian M. Null, George W. Vaughan, Andrew T. TI The challenges of deep impact autonomous navigation SO JOURNAL OF FIELD ROBOTICS LA English DT Article AB On July 4, 2005 at 05:44:34 UTC the Impactor spacecraft (s/c) impacted comet 9P/Tempel 1 with a relative speed of more than 10 km/s. The Flyby s/c captured the impact event, using both the medium resolution imager and the high resolution imager, and tracked the impact site for the entire observing period following impact. The objective of the Impactor s/c was to impact in an illuminated area viewable from the Flyby s/c and telemeter high-resolution context images of the impact site prior to impact. The Flyby s/c had two primary objectives: (1) capture the impact event in order to observe the ejecta plume expansion dynamics and (2) track the impact site for at least 800 s to observe the crater formation and capture high-resolution images of the fully developed crater. All of these objectives were met by estimating the trajectory of each spacecraft relative to 9P/Tempel I using the autonomous navigation system, precise attitude information from the attitude determination and control subsystem, and allowing each spacecraft to independently select the same impact site. This paper describes the challenges of targeting and tracking comet 9P/Tempel 1. (c) 2007 Wiley Periodicals, Inc. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kubitschek, DG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM daniel.kubitschek@jpl.nasa.gov; nick.mastrodemos@jpl.nasa.gov; robert.werner@jpl.nasa.gov; stephen.p.synnott@jpl.nasa.gov; shyam@jpl.nasa.gov; ed.riedel@jpl.nasa.gov; brian.kennedy@jpl.nasa.gov; george.null@jpl.nasa.gov; andrew.t.vaughan@jpl.nasa.gov NR 8 TC 4 Z9 4 U1 0 U2 1 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 1556-4959 J9 J FIELD ROBOT JI J. Field Robot. PD APR PY 2007 VL 24 IS 4 BP 339 EP 354 DI 10.1002/rob.20177 PG 16 WC Robotics SC Robotics GA 162RX UT WOS:000246108300005 ER PT J AU Scheurer, JA Berejikian, BA Thrower, FP Ammann, ER Flagg, TA AF Scheurer, J. A. Berejikian, B. A. Thrower, F. P. Ammann, E. R. Flagg, T. A. TI Innate predator recognition and fright response in related populations of Oncorhynchus mykiss under different predation pressure SO JOURNAL OF FISH BIOLOGY LA English DT Article DE Oncorhynchus mykiss; predator recognition; Salvelinus malma; scent ID CHEMICAL ALARM CUES; ANTIPREDATOR BEHAVIOR; CHINOOK SALMON; GENETIC-DIVERGENCE; ATLANTIC SALMON; BROWN TROUT; WILD; HATCHERY; EVOLUTION; DOMESTICATION AB Innate predator recognition and fright response behaviours were compared in a laboratory study between second generation offspring from two related populations of steelhead trout Oncorhynchus mykiss from Sashin Creek, Alaska. The stream population was anadromous and co-occurred with Dolly Varden Salvelinus malma, a piscivore and salmonid predator. Sashin Lake, formerly fishless, was stocked with fish from the stream population in 1926 and that population has been isolated from heterospecific piscine predation ever since. Fish from the lake population were predicted to show diminished innate fright response to Dolly Varden scent relative to the stream population. The behaviour of 60 individual juvenile O. mykiss from each population was measured and observed in aquaria before and after exposure to chemical cues of Dolly Varden, conspecific skin extract, or a control of distilled water. The alarm substances caused significant behavioural changes in both populations in the amount of time spent motionless, time spent in the lower water column and feeding frequency. No significant differences were observed between the stream and lake populations in the change in behaviour between pre- and post-stimulus observation periods for any of the measured fright responses, indicating that the sequestered lake population has not lost the ability to detect or respond to conspecific alarm substances or Dolly Varden scent. (c) 2007 The Fisheries Society of the British Isles. C1 NOAA Fisheries, NW Fisheries Sci Ctr, Manchester Res Stn, Manchester, WA 98353 USA. NOAA Fisheries, Alaska Fisheries Sci Ctr, Juneau, AK 99801 USA. Univ Alaska Fairbanks, Juneau Ctr Fisheries & Ocean Sci, Juneau, AK 99801 USA. RP Scheurer, JA (reprint author), Natl Marine Fisheries Serv, Sustainable Fisheries Div, POB 21668, Juneau, AK 99802 USA. EM julie.scheurer@noaa.gov NR 36 TC 12 Z9 13 U1 4 U2 22 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0022-1112 EI 1095-8649 J9 J FISH BIOL JI J. Fish Biol. PD APR PY 2007 VL 70 IS 4 BP 1057 EP 1069 DI 10.1111/j.1095-8649.2007.01367.x PG 13 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 155WP UT WOS:000245609600006 ER PT J AU Chen, JL Wilson, CR Famiglietti, JS Rodell, M AF Chen, J. L. Wilson, C. R. Famiglietti, J. S. Rodell, Matt TI Attenuation effect on seasonal basin-scale water storage changes from GRACE time-variable gravity SO JOURNAL OF GEODESY LA English DT Article DE GRACE; spatial smoothing; water storage estimation; seasonal variations; attenuation effect ID ART.; VARIABILITY; RECOVERY; SYSTEM AB In order to effectively recover surface mass or geoid height changes from the gravity recovery and climate experiment (GRACE) time-variable gravity models, spatial smoothing is required to minimize errors from noise. Spatial smoothing, such as Gaussian smoothing, not only reduces the noise but also attenuates the real signals. Here we investigate possible amplitude attenuations and phase changes of seasonal water storage variations in four drainage basins (Amazon, Mississippi, Ganges and Zambezi) using an advanced global land data assimilation system. It appears that Gaussian smoothing significantly affects GRACE-estimated basin-scale seasonal water storage changes, e.g., in the case of 800 km smoothing, annual amplitudes are reduced by about 25-40%, while annual phases are shifted by up to 10 degrees. With these effects restored, GRACE-estimated water storage changes are consistently larger than model estimates, indicating that the land surface model appears to underestimate terrestrial water storage change. Our analysis based on simulation suggests that normalized attenuation effects (from Gaussian smoothing) on seasonal water storage change are relatively insensitive to the magnitude of the true signal. This study provides a numerical approach that can be used to restore seasonal water storage change in the basins from spatially smoothed GRACE data. C1 Univ Texas, Ctr Space Res, Austin, TX 78759 USA. Univ Texas, Dept Geol Sci, Austin, TX 78712 USA. Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Chen, JL (reprint author), Univ Texas, Ctr Space Res, 3925 W Braker Lane,Suite 200, Austin, TX 78759 USA. EM chen@csr.utexas.edu; crwilson@mail.utexas.edu; jfamigli@uci.edu; Matthew.Rodell@nasa.gov RI Rodell, Matthew/E-4946-2012 OI Rodell, Matthew/0000-0003-0106-7437 NR 21 TC 46 Z9 51 U1 0 U2 12 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0949-7714 EI 1432-1394 J9 J GEODESY JI J. Geodesy PD APR PY 2007 VL 81 IS 4 BP 237 EP 245 DI 10.1007/s00190-006-0104-2 PG 9 WC Geochemistry & Geophysics; Remote Sensing SC Geochemistry & Geophysics; Remote Sensing GA 152JW UT WOS:000245359300001 ER PT J AU Ray, RD AF Ray, R. D. TI Tidal analysis experiments with sun-synchronous satellite altimeter data SO JOURNAL OF GEODESY LA English DT Article DE tides; satellite altimetry; ERS altimetry ID TOPEX/POSEIDON ALTIMETRY; OCEAN TIDES; ICE SHELF; SPECTROSCOPY; PREDICTION; MODELS AB The ERS-1, ERS-2 and Envisat series of satellite altimeters provide the only extensive datasets that could conceivably be usedto constrain ocean tide models in high latitudes. Their sun-synchronous sampling, however, severely limits theobservations of solar tides, especially the principal semidiurnal S-2 constituent. The Munk-Cartwright response method is anatural choice when attempting to analyze sun-synchronous data. The present study examines various ways a response analysis might be implemented to extract tides from ERS data. Admittances expressed as simple linear or constant functions of frequency cansometimes improve estimates over standard parameterizations, especially if done in conjunction with a reasonably accurate priorsolution. Some form of regularization, such as ridge regression, is also shown to improve the estimates. The approach provesbeneficial in a test for the southern Indian Ocean tides. It offers some promise for regions otherwise void of usefulobservations. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ray, RD (reprint author), NASA, Goddard Space Flight Ctr, Code 697, Greenbelt, MD 20771 USA. EM richard.ray@nasa.gov RI Ray, Richard/D-1034-2012 NR 29 TC 3 Z9 3 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0949-7714 EI 1432-1394 J9 J GEODESY JI J. Geodesy PD APR PY 2007 VL 81 IS 4 BP 247 EP 257 DI 10.1007/s00190-006-0105-1 PG 11 WC Geochemistry & Geophysics; Remote Sensing SC Geochemistry & Geophysics; Remote Sensing GA 152JW UT WOS:000245359300002 ER PT J AU Zhang, W Fisher, TS Mingo, N AF Zhang, W. Fisher, T. S. Mingo, N. TI Simulation of interfacial phonon transport in Si-Ge heterostructures using an atomistic Green's function method SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT ASME International Mechanical Engineering Congress and Exposition CY NOV 05-11, 2005 CL Orlando, FL SP ASME, Proc Ind Div, ASME, Rail Transportat Div, ASME, Noise Control & Acoust Div, ASME, Triol Div, ASME, Pressure Vessels & Piping Div, ASME, Bioengn Div, ASME, Mat Div, ASME, Appl Mech Div, ASME, Fluids Engn Div, ASME, Micro Elect Mech Syst Div, ASME, Heat Transfer Div, ASME, Nucl Engn Div, ASME, Power Div, ASME, Solar Energy Div, ASME, Safety Engn & Risk Anal Div, ASME, Technol & Soc Div, ASME, Adv Energy Syst Div, ASME, Aerosp Div, ASME, Comp & Informat Engn Div ID THERMAL-BOUNDARY RESISTANCE; MOLECULAR-DYNAMICS; LOW-TEMPERATURES; STRAIN; SUPERLATTICES; CONDUCTIVITY; HEAT; SILICON; SOLIDS; CONDUCTANCE AB An atomistic Greens function method is developed to simulate phonon transport across a strained germanium (or silicon) thin film between two semi-infinite silicon (or germanium) contacts. A plane-wave formulation is employed to handle the translational symmetry in directions parallel to the interfaces. The phonon transmission function and thermal conductance across the thin film are evaluated for various atomic configurations. The contributions from lattice straining and material heterogeneity are evaluated separately, and their relative magnitudes are characterized. The dependence of thermal conductance on film thickness is also calculated, verifying that the thermal conductance reaches an asymptotic value for very thick films. The thermal boundary resistance of a single Si/Ge interface is computed and agrees well with analytical model predictions. Multiple-interface effects on thermal resistance are investigated, and the results indicate that the first few interfaces have the most significant effect on the overall thermal resistance. C1 Purdue Univ, Birck Nanotechnol Ctr, Sch Mech Engn, W Lafayette, IN 47907 USA. NASA, Ames Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Zhang, W (reprint author), Purdue Univ, Birck Nanotechnol Ctr, Sch Mech Engn, W Lafayette, IN 47907 USA. EM tsfisher@purdue.edu RI Fisher, Timothy/D-8517-2011 OI Fisher, Timothy/0000-0002-8909-313X NR 42 TC 84 Z9 84 U1 3 U2 21 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD APR PY 2007 VL 129 IS 4 BP 483 EP 491 DI 10.1115/1.2709656 PG 9 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 167FY UT WOS:000246438100009 ER PT J AU Arora, A Mendoza, N Mehta, S Tyring, S AF Arora, A. Mendoza, N. Mehta, S. Tyring, S. TI Salivary VZV DNA SO JOURNAL OF INVESTIGATIVE DERMATOLOGY LA English DT Meeting Abstract CT 68th Annual Meeting of the Society-for-Investigative-Dermatology CY MAY 09-12, 2007 CL Los Angeles, CA SP Soc Investigat Dermatol C1 Ctr Clin Studies, Houston, TX USA. NASA, Houston, TX USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NATURE PUBLISHING GROUP PI NEW YORK PA 75 VARICK STREET, 9TH FLOOR, NEW YORK, NY 10013-1917 USA SN 0022-202X J9 J INVEST DERMATOL JI J. Invest. Dermatol. PD APR PY 2007 VL 127 SU 1 MA 797 BP S133 EP S133 PG 1 WC Dermatology SC Dermatology GA 152UP UT WOS:000245387800790 ER PT J AU Currie, JR Batra, AK Alim, MA Aggarwal, MD Lal, RB AF Currie, James R. Batra, Ashok K. Alim, Mohammad A. Aggarwal, Manmohan D. Lal, Ravindra B. TI Impedance studies of polycrystalline tin oxide SO JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS LA English DT Article ID ZNO-BASED VARISTORS; BEHAVIOR; CASNO3 AB Polycrystalline SnO2 samples prepared in the laboratory were irradiated with 2 MeV He ions having doses of 3.62 x 10(15) ion/cm(2). The ac small-signal electrical data acquired for the polycrystalline SnO2 in the frequency ( f) range 100 Hz <= f <= 1 MHz and temperature ( T) range 26 degrees C <= T <= 100 degrees C revealed one semicircular relaxation in the impedance plane for the He implanted sample. However, two semicircular relaxations were obtained in the same plane for the samples without He implantation. The He implantation indicated enhancement in the donor density in the polycrystalline SnO2 as depicted via terminal conductance (or resistance). C1 Alabama A&M Univ, Dept Elect Engn, Normal, AL 35762 USA. NASA, Avion Dept, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Alabama A&M Univ, Dept Phys, Normal, AL 35762 USA. RP Alim, MA (reprint author), Alabama A&M Univ, Dept Elect Engn, POB 297, Normal, AL 35762 USA. EM ashok.batra@email.aamu.edu; mohammad.alim@email.aamu.edu NR 16 TC 5 Z9 5 U1 1 U2 6 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0957-4522 J9 J MATER SCI-MATER EL JI J. Mater. Sci.-Mater. Electron. PD APR PY 2007 VL 18 IS 4 BP 433 EP 439 DI 10.1007/s10854-006-9037-z PG 7 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Engineering; Materials Science; Physics GA 124VG UT WOS:000243397500011 ER PT J AU Oterkus, E Madenci, E Nemeth, MP AF Oterkus, Erkan Madenci, Erdogan Nemeth, Michael P. TI Stress analysis of composite cylindrical shells with an elliptical cutout SO JOURNAL OF MECHANICS OF MATERIALS AND STRUCTURES LA English DT Article DE cylindrical; composite; cutout; stress ID CIRCULAR HOLE; COMPRESSION; DEFORMATION; THICKNESS; CYLINDERS; EQUATIONS; PRESSURE; THIN AB A special-purpose, semianalytical solution method for determining the stress and deformation fields in a thin, laminated-composite cylindrical shell with an elliptical cutout is presented. The analysis includes the effects of cutout size, shape, and orientation; nonuniform wall thickness; oval cross-sectional eccentricity; and loading conditions. The loading conditions include uniform tension, uniform torsion, and pure bending. The analysis approach is based on the principle of stationary potential energy and uses Lagrange multipliers to relax the kinematic admissibility requirements on the displacement representations through the use of idealized elastic edge restraints. Specifying appropriate stiffness values for the elastic extensional and rotational edge restraints (springs) allows the imposition of the kinematic boundary conditions in an indirect manner, which enables the use of a broader set of functions for representing the displacement fields. Selected results of parametric studies are presented for several geometric parameters that demonstrate that this analysis approach is a powerful means for developing design criteria for laminated-composite shells. C1 [Oterkus, Erkan; Madenci, Erdogan] Univ Arizona, Dept Aerosp & Mech Engn, Tucson, AZ 85721 USA. [Nemeth, Michael P.] NASA, Langley Res Ctr, Struct Mech & Concepts Branch, Hampton, VA 23681 USA. RP Oterkus, E (reprint author), Univ Arizona, Dept Aerosp & Mech Engn, Tucson, AZ 85721 USA. EM oterkus@email.arizona.edu; madenci@email.arizona.edu NR 42 TC 4 Z9 4 U1 0 U2 3 PU MATHEMATICAL SCIENCE PUBL PI BERKELEY PA UNIV CALIFORNIA, DEPT MATHEMATICS, BERKELEY, CA 94720-3840 USA SN 1559-3959 J9 J MECH MATER STRUCT JI J. Mech. Mater. Struct. PD APR PY 2007 VL 2 IS 4 BP 695 EP 727 DI 10.2140/jomms.2007.2.695 PG 33 WC Materials Science, Multidisciplinary; Mechanics SC Materials Science; Mechanics GA 306TB UT WOS:000256269600006 ER PT J AU Devi, VM Benner, DC Brown, LR Miller, CE Toth, RA AF Devi, V. Malathy Benner, D. Chris Brown, L. R. Miller, C. E. Toth, R. A. TI Line mixing and speed dependence in CO2 at 6348 cm(-1): Positions, intensities, and air- and self-broadening derived with constrained multispectrum analysis SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article DE CO2; positions; intensities and pressure broadening; off-diagonal relaxation matrix elements; line mixing; Lorentz widths; pressure shifts; near infrared ID 20 MU-M; MOLECULAR SPECTROSCOPIC DATABASE; PRESSURE-SHIFT COEFFICIENTS; NEAR-INFRARED SPECTROSCOPY; CARBON-DIOXIDE; WING REGIONS; LASER SPECTROSCOPY; BANDS; (CO2)-C-12-O-16; PARAMETERS AB Intensity and line shape parameters which predict spectral lines with absolute accuracies better than 0.3% have been determined for transitions of the 30012 <- 00001 band of 11012 00 centered near 6348 cm(-1) from 26 high resolution, high signal-to-noise ratio spectra recorded at room temperature with the McMath-Pierce Fourier transform spectrometer. To maximize the accuracies of the retrieved parameters, the multispectrum non-linear least squares retrieval technique was modified to adjust the rovibrational constants (G, B, D, etc.) and intensity parameters, including Herman-Wallis terms, rather than retrieving the individual positions and intensities. Speed-dependent Voigt line shapes with line mixing were required to remove systematic errors in the fit residuals. Self- and air-broadening (widths and pressure-induced shifts, speed dependence parartieters) and line mixing (off-diagonal relaxation matrix elements) coefficients were thus obtained in the multispectrum fit. Remaining errors were minimized by fitting the weak 30011 <- 00001 band of (OCO)-O-16-C-13-O-16 as well as the weak hot bands 31112 <- 01101, 32212 <- 02201, 40012 <- 10001, and 40013 <- 10002 of (OCO)-O-16-C-12-O-16 that contribute interfering absorptions in this spectral window. This study presents the most extensive set of measurements to date for self- and airbroadening and self- and air-shift coefficients of a near infrared band of CO2, This is also the first study where line mixing parameters have been experimentally determined for any parallel CO2 band. (c) 2007 Elsevier Inc. All rights reserved. C1 Coll William & Mary, Williamsburg, VA 23187 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Devi, VM (reprint author), Coll William & Mary, Box 8795, Williamsburg, VA 23187 USA. EM m.d.venkataraman@larc.nasa.gov NR 47 TC 75 Z9 74 U1 0 U2 17 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD APR PY 2007 VL 242 IS 2 BP 90 EP 117 DI 10.1016/j.jms.2007.02.018 PG 28 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 183LX UT WOS:000247575400003 ER PT J AU Hartman, MR Rush, JJ Udovic, TJ Bowman, RC Hwang, SJ AF Hartman, Michael R. Rush, John J. Udovic, Terrence J. Bowman, Robert C., Jr. Hwang, Son-Jong TI Structure and vibrational dynamics of isotopically labeled lithium borohydride using neutron diffraction and spectroscopy SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article DE neutron scattering; lithium borohydride; NMR; hydrogen storage ID ALKALI BOROHYDRIDES; LIBH4; HYDROGEN; HYDRIDES; STORAGE; SODIUM; RAMAN AB The crystalline structure of a Li-7 and B-11 labeled lithium borohydride has been investigated using neutron powder diffraction at 3.5, 360, and 400 K. The B-H bond lengths and H-B-H angles for the [BH4](-) tetrahedra indicated that the tetrahedra maintained a nearly ideal configuration throughout the temperature range investigated. The atomic displacement parameters at 360 K suggest that the [BH4](-) tetrahedra become increasingly disordered as a result of large amplitude librational and reorientational motions as the orthorhombic to hexagonal phase transition (T = 384 K) is approached. In the high-temperature hexagonal phase, the [BH4](-) tetrahedra displayed extreme disorder about the trigonal axis along which they are aligned. Neutron vibrational spectroscopy data were collected at 5 K over an energy range of 10-170meV, and were found to be in good agreement with prior Raman and low-resolution neutron spectroscopy studies. (C) 2007 Elsevier Inc. All rights reserved. C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Div Chem & Chem Engn, Pasadena, CA 91125 USA. RP Hartman, MR (reprint author), Oregon State Univ, Radiat Ctr 100, Corvallis, OR 97331 USA. EM mike.hartman@oregonstate.edu OI Bowman, Robert/0000-0002-2114-1713 NR 19 TC 124 Z9 124 U1 1 U2 33 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD APR PY 2007 VL 180 IS 4 BP 1298 EP 1305 DI 10.1016/j.jsssc.2007.01.031 PG 8 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 165RO UT WOS:000246323400018 ER PT J AU Wilkinson, A DeGennaro, A AF Wilkinson, Allen DeGennaro, Alfred TI Digging and pushing lunar regolith: Classical soil mechanics and the forces needed for excavation and traction SO JOURNAL OF TERRAMECHANICS LA English DT Review AB There are many notional systems for excavating lunar regolith in NASA's Exploration Vision. Quantitative system performance comparisons are scarce in the literature. This paper focuses on the required forces for excavation and traction as quantitative predictors of system feasibility. The rich history of terrestrial soil mechanics is adapted to extant lunar regolith parameters to calculate the forces. The soil mechanics literature often acknowledges the approximate results from the numerous excavation force models in use. An intent of this paper is to examine their variations in the lunar context. Six excavation models and one traction model are presented. The effects of soil properties are explored for each excavation model, for example, soil cohesion and friction, tool-soil adhesion, and soil density. Excavation operational parameters like digging depth, rake angle, gravity, and surcharge are examined. For the traction model, soil, operational, and machine design parameters are varied to probe choices. Mathematical anomalies are noted for several models. One conclusion is that the excavation models yield such, isparate results that lunar-field testing is prudent. All the equations and graphs presented have been programmed for design use. Parameter ranges and units are included. Published by Elsevier Ltd on behalf of ISTVS. C1 NASA, Glenn Res Ctr, Fluid Phys & Transport Branch, Cleveland, OH 44135 USA. RP Wilkinson, A (reprint author), NASA, Glenn Res Ctr, Fluid Phys & Transport Branch, MS 110-3,21000 Brookpk Rd, Cleveland, OH 44135 USA. EM aw@grc.nasa.gov NR 24 TC 23 Z9 26 U1 0 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4898 J9 J TERRAMECHANICS JI J. Terramech. PD APR PY 2007 VL 44 IS 2 BP 133 EP 152 DI 10.1016/j.jterra.2006.09.001 PG 20 WC Engineering, Environmental SC Engineering GA 146ID UT WOS:000244926800001 ER PT J AU Fasanella, EL Jackson, KE Lyle, KH Sparks, CE Sateen, AK AF Fasanella, Edwin L. Jackson, Karen E. Lyle, Karen H. Sparks, Chad E. Sateen, Ashish K. TI Multi-terrain impact tests and simulations of an energy absorbing fuselage section SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article; Proceedings Paper CT 60th Annual Forum of the American-Helicopter-Society CY JUN 07-10, 2004 CL Baltimore, MD SP Amer Helicopter Soc AB Comparisons of the impact performance of a 5 ft diameter crashworthy composite fuselage section were investigated for hard surface, soft soil, and water impacts. The fuselage concept, which was originally designed for impacts onto a hard surface only, consisted of a stiff upper cabin, load bearing floor, and an energy absorbing subfloor. Vertical drop tests were performed at 25 ft/s onto concrete, soft soil, and water. Comparisons of the peak acceleration values, pulse durations, and onset rates were evaluated for each test at specific locations on the fuselage. In addition to comparisons of the experimental results, dynamic finite element models were developed to simulate each impact condition. Once validated, these models can be used to evaluate the dynamic behavior of subfloor components for improved crash protection for hard surface, soft soil, and water impacts. C1 NASA, Langley Res Ctr, Struct Dynam Branch, Hampton, VA 23665 USA. Bell Helicopter Texton Inc, Program Qual, Ft Worth, TX USA. RP Fasanella, EL (reprint author), NASA, Langley Res Ctr, Struct Dynam Branch, Hampton, VA 23665 USA. EM Edwin.L.Fasanella@nasa.gov NR 17 TC 6 Z9 6 U1 0 U2 3 PU AMER HELICOPTER SOC INC PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314 USA SN 0002-8711 J9 J AM HELICOPTER SOC JI J. Am. Helicopter Soc. PD APR PY 2007 VL 52 IS 2 BP 159 EP 168 PG 10 WC Engineering, Aerospace SC Engineering GA 165EJ UT WOS:000246286500008 ER PT J AU Huntington, GT Benson, D Rao, AV AF Huntington, Geoffrey T. Benson, David Rao, Anil V. TI Optimal configuration of tetrahedral spacecraft formations SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article; Proceedings Paper CT AAS/AIAA 15th Space Flight Mechanics Meeting CY JAN 23-27, 2005 CL Copper Mt, CO SP AAS, AIAA ID DIRECT TRAJECTORY OPTIMIZATION; FORMATION FLYING GUIDANCE; PSEUDOSPECTRAL METHOD; COSTATE ESTIMATION; COLLOCATION; SYSTEMS AB The problem of determining minimum-fuel maneuver sequences for a four-spacecraft formation is considered. The objective of this paper is to find fuel-optimal spacecraft trajectories that transfer four spacecraft from an initial parking orbit to a desired terminal reference orbit while satisfying a set of constraints on the formation at the terminal time. Trajectories involving both one and two allowable maneuvers per spacecraft are considered. The resulting nonlinear optimal control problem is solved numerically using a recently developed direct transcription method called the Gauss pseudospectral method. The results presented in this paper highlight interesting features of the fuel-optimal formation and control. Furthermore, by showing that the discretized first-order optimality conditions from an indirect formulation are satisfied, a post-optimality analysis of the results demonstrates the accuracy and usefulness of the Gauss pseudospectral method. C1 [Huntington, Geoffrey T.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Rao, Anil V.] Charles Stark Draper Lab Inc, Control Syst Div, Cambridge, MA 02139 USA. RP Huntington, GT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Geoffrey.T.Huntington@jpl.nasa.gov; dbenson@draper.com; anilvrao@ufl.edu NR 44 TC 20 Z9 20 U1 0 U2 1 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 USA SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD APR-JUN PY 2007 VL 55 IS 2 BP 141 EP 169 PG 29 WC Engineering, Aerospace SC Engineering GA 297LD UT WOS:000255617300001 ER PT J AU Lang, S Tao, WK Cifelli, R Olson, W Halverson, J Rutledge, S Simpson, J AF Lang, S. Tao, W.-K. Cifelli, R. Olson, W. Halverson, J. Rutledge, S. Simpson, J. TI Improving simulations of convective systems from TRMM LBA: Easterly and westerly regimes SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID MEASURING MISSION TRMM; TROPICAL SQUALL-LINE; LATENT-HEAT RELEASE; STRATIFORM PRECIPITATION PROCESSES; ADVECTION TRANSPORT ALGORITHM; VERTICAL HYDROMETEOR PROFILES; SMALL IMPLICIT DIFFUSION; DIURNAL CYCLE; TOGA COARE; CLOUD MODEL AB The 3D Goddard Cumulus Ensemble model is used to simulate two convective events observed during the Tropical Rainfall Measuring Mission Large-Scale Biosphere-Atmosphere (TRMM LBA) experiment in Brazil. These two events epitomized the type of convective systems that formed in two distinctly different environments observed during TRMM LBA. The 26 January 1999 squall line formed within a sheared low-level easterly wind flow. On 23 February 1999, convection developed in weak low-level westerly flow, resulting in weakly organized, less intense convection. Initial simulations captured the basic organization and intensity of each event. However, improvements to the model resolution and microphysics produced better simulations as compared to observations. More realistic diurnal convective growth was achieved by lowering the horizontal grid spacing from 1000 to 250 m. This produced a gradual transition from shallow to deep convection that occurred over a span of hours as opposed to an abrupt appearance of deep convection. Eliminating the dry growth of graupel in the bulk microphysics scheme effectively removed the unrealistic presence of high-density ice in the simulated anvil. However, comparisons with radar reflectivity data using contoured-frequency- with-altitude diagrams (CFADs) revealed that the resulting snow contents were too large. The excessive snow was reduced primarily by lowering the collection efficiency of cloud water by snow and resulted in further agreement with the radar observations. The transfer of cloud-sized particles to precipitation-sized ice appears to be too efficient in the original scheme. Overall, these changes to the microphysics lead to more realistic precipitation ice contents in the model. However, artifacts due to the inability of the one-moment scheme to allow for size sorting, such as excessive low-level rain evaporation, were also found but could not be resolved without moving to a two-moment or bin scheme. As a result, model rainfall histograms underestimated the occurrence of high rain rates compared to radar-based histograms. Nevertheless, the improved precipitation-sized ice signature in the model simulations should lead to better latent heating retrievals as a result of both better convective-stratiform separation within the model as well as more physically realistic hydrometeor structures for radiance calculations. C1 NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Atmospheres Lab, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. RP Lang, S (reprint author), NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Atmospheres Lab, Code 613-1, Greenbelt, MD 20771 USA. EM lang@agnes.gsfc.nasa.gov NR 84 TC 90 Z9 94 U1 1 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2007 VL 64 IS 4 BP 1141 EP 1164 DI 10.1175/JAS3879.1 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 157TA UT WOS:000245742600007 ER PT J AU Gupta, S Tannehill, JC Mehta, UB Bogdanoff, DW AF Gupta, Sumeet Tannehill, John C. Mehta, Unmeel B. Bogdanoff, David W. TI Simulation of 3-D nonequilibrium seeded airflow in the NASA Ames MHD channel SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article; Proceedings Paper CT AIAA 43rd Aerospace Sciences Meeting and Exhibit CY JAN 10-13, 2005 CL Reno, NV SP AIAA AB The 3-D nonequilibrium seeded airflow in the NASA Ames experimental magnetohydrodynamics channel has been numerically simulated. The channel contains a nozzle section, a center section, and an accelerator section in which magnetic and electric fields can be imposed on the flow. In recent tests, velocity increases of up to 40% have been achieved in the accelerator-section. The flow in the channel is numerically computed using a 3-D parabolized Navier-Stokes algorithm that has been developed to efficiently compute magnetohydrodynamics flows in the low magnetic Reynolds number regime. The magnetohydrodynamics effects are modeled by introducing source terms into the parabolized Navier-Stokes equations, which can then be solved in a very efficient manner. The algorithm has been extended in the present study to account for nonequilibrium seeded airflows. The electrical conductivity of the flow is determined using the program of Park. The new algorithm has been used to compute two test cases that match the experimental conditions. In both cases, magnetic and electric fields are applied to the seeded flow. The computed results are in good agreement with the experimental data. C1 Iowa State Univ, Computat Fluid Dynam Ctr, Ames, IA 50011 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Iowa State Univ, Dept Aerosp Engn, Ames, IA 50011 USA. ELORET Corp, Sunnyvale, CA 94086 USA. RP Gupta, S (reprint author), Iowa State Univ, Computat Fluid Dynam Ctr, Ames, IA 50011 USA. NR 34 TC 5 Z9 7 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD APR-JUN PY 2007 VL 21 IS 2 BP 276 EP 283 DI 10.2514/1.15811 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 157BK UT WOS:000245693400003 ER PT J AU McClain, ST Vargas, M Kreeger, RE Tsao, JC AF McClain, Stephen T. Vargas, Mario Kreeger, Richard E. Tsao, Jen-Ching TI Heat transfer from protuberances SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article; Proceedings Paper CT AIAA 44th Aerospace Sciences Meeting and Exhibit CY JAN 09-12, 2006 CL Reno, NV SP AIAA AB An experiment by Henry et al. (Henry, R. C., Hausman, R. J., Breuer, K. S., "Heat Transfer Variation on Protuberances and Surface Roughness Elements," Journal of Thermophysics and Heat Transfer, Vol. 91, Mar. 1995, pp. 175-180.) explored the heat transfer of flows over protuberances in laminar and turbulent flow, simulating conditions during the beginning stages of glaze icing. This paper represents an effort to explain the heat transfer enhancement of roughness elements and protuberances that was observed by Henry et al. In the experiments of Henry et al., a single roughness element was placed on a heated flat plate. The temperature along the flat plate and along the roughness element was measured using an infrared camera to determine the enhancement of heat transfer of the protuberance as opposed to the smooth surface. A one-dimensional extended-surface (fin) analysis was performed to examine the results of Henry et al. Although significant assumptions were made using the extended-surface analysis, the important trends of the Henry et al. data were captured. The extended-surface analysis captured the trends of the apparent enhancement as reported by Henry et al. vs the Reynolds number based on the location from the leading edge of the surface and vs the ratio of the protuberance height to the boundary-layer thickness. Although the absolute magnitudes of the apparent enhancement are overestimated by the extended-surface analysis, the matched trends indicate the importance of the thermal conductivity of the protuberance, the importance of the interaction of the protuberance with the thermal boundary layer, and the importance of radiation into the protuberance. C1 Univ Alabama, Dept Mech Engn, Birmingham, AL 35294 USA. NASA, John H Glenn Res Ctr Lewis Field, Icing Res Branch, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Icing Res Branch, Cleveland, OH 44135 USA. RP McClain, ST (reprint author), Univ Alabama, Dept Mech Engn, 1530 3rd Ave S,BEC Bldg,Room 358B, Birmingham, AL 35294 USA. NR 11 TC 4 Z9 4 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD APR-JUN PY 2007 VL 21 IS 2 BP 337 EP 345 DI 10.2514/1.23186 PG 9 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 157BK UT WOS:000245693400009 ER PT J AU Thunnissen, DP Au, SK Tsuyuki, GT AF Thunnissen, Daniel P. Au, Siu Kui Tsuyuki, Glenn T. TI Uncertainty quantification in estimating critical spacecraft component temperatures SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article AB A method for quantifying uncertainty in conceptual-level design via a computationally efficient probabilistic method is presented. The investigated method is applied to estimating the maximum-expected temperature of several critical components on a spacecraft. The variables of the design are first classified and assigned appropriate probability density functions. To characterize the thermal control system of the spacecraft, Subset Simulation, an efficient simulation technique originally developed for reliability analysis of civil engineering structures, is used. The results of Subset Simulation are compared with traditional Monte Carlo simulation. The investigated method allows uncertainty in the maximum-expected temperatures to be quantified based on the risk tolerance of the decision maker. For the spacecraft thermal control problem presented, Subset Simulation successfully replicated Monte Carlo simulation results for estimating the maximum-expected temperatures of several critical components yet required significantly less computational effort, in particular for risk-averse decision makers. C1 Nanyang Technol Univ, Sch Mech & Aerosp Engn, Singapore 639668, Singapore. City Univ Hong Kong, Dept Bldg & Construct, Hong Kong, Hong Kong, Peoples R China. CALTECH, Jet Prop Lab, Thermal & Cryogen Engn Sect, Pasadena, CA 91109 USA. RP Thunnissen, DP (reprint author), Nanyang Technol Univ, Sch Mech & Aerosp Engn, 50 Nanyang Ave, Singapore 639668, Singapore. RI Au, Siu-Kui/A-2947-2011 OI Au, Siu-Kui/0000-0002-0228-1796 NR 18 TC 5 Z9 5 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD APR-JUN PY 2007 VL 21 IS 2 BP 422 EP 430 DI 10.2514/1.23979 PG 9 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 157BK UT WOS:000245693400018 ER PT J AU Basdogan, I Elias, LM Dekens, F Sievers, L AF Basdogan, Ipek Elias, Laila Mireille Dekens, Frank Sievers, Lisa TI Predicting the optical performance of the space interferometry mission using a modeling, testing, and validation methodology SO JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME LA English DT Article AB This paper presents the modeling, testing, and validation methodologies developed to predict the optical performance of the Space Interferometry Mission (SIM) at the Jet Propulsion Laboratory (JPL). The modeling methodology combines structural, optical, and control system design within a common state space framework and incorporates reaction wheel assembly (RWA) disturbances to evaluate the end-to-end performance of the system requirements. The validation methodology uses the Micro-Precision Interferometer (MPI) testbed, which is a ground-based, representative hardware model of SIM. In this study, the integrated model of the MPI testbed was used to calculate the transfer functions from RWA input to optical performance output. The model-predicted transfer functions were compared with the MPI testbed measurements, and the accuracy of the integrated model was quantified using a metric that was based on output power of the transfer functions. The RWA disturbances were then propagated through the modeled and measured transfer functions to predict the optical performance of the MPI testbed. This method is called the "decoupled disturbance analysis" and relies on the "blocked" RWA disturbances, measured with the RWA hardmounted to a rigid surface. These predictions were compared with the actual (measured) optical performance of MPI, measured with the RWA mounted to MPI, to evaluate the accuracy of the decoupled disturbance analysis method The results show that this method is not an accurate representation of the coupled boundary conditions that occurs when the RWA is mounted to the flexible MPI structure. In order to correct for the blocked RWA disturbance boundary conditions, the "coupled disturbance analysis" method was developed. This method uses "force filters" that depend on estimates of the interface accelerances of the RWA and the MPI structure to effectively transform the blocked RWA disturbance measurements into their corresponding "coupled" disturbances (the disturbances that would occur at the coupled RWA-MPI interface). Compared to the decoupled method, the coupled method more accurately predicts the system's performance. Additionally, the RWA cross-spectral density terms were found to be influential in matching the performance Predictions to the measured optical performance of MPI. C1 Koc Univ, Dept Mech Engn, TR-80910 Istanbul, Turkey. MIT, Space Syst Lab, Cambridge, MA 02139 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Basdogan, I (reprint author), Koc Univ, Dept Mech Engn, TR-80910 Istanbul, Turkey. NR 18 TC 7 Z9 8 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 1048-9002 J9 J VIB ACOUST JI J. Vib. Acoust.-Trans. ASME PD APR PY 2007 VL 129 IS 2 BP 148 EP 157 DI 10.1115/1.2202152 PG 10 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 155UO UT WOS:000245604100003 ER PT J AU Aguirre, AA Keefe, TJ Reif, JS Kashinsky, L Yochem, PK Saliki, JT Stott, JL Goldstein, T Dubey, JP Braun, R Antonelis, G AF Aguirre, A. Alonso Keefe, Thomas J. Reif, John S. Kashinsky, Lizabeth Yochem, Pamela K. Saliki, Jeremiah T. Stott, Jeffrey L. Goldstein, Tracey Dubey, J. P. Braun, Robert Antonelis, George TI Infectious disease monitoring of the endangered Hawaiian monk seal SO JOURNAL OF WILDLIFE DISEASES LA English DT Article DE Brucella; Chlamydophila; Hawaiian monk seal; Leptospira bratislava; Monachus schauinslandi; phocine herpesvirus; serology; Toxoplasma gondii ID MONACHUS-SCHAUINSLANDI; TOXOPLASMA-GONDII; MOLECULAR-IDENTIFICATION; CHLAMYDOPHILA-ABORTUS; MARINE MAMMALS; PHOCA-VITULINA; ENHYDRA-LUTRIS; CELL-LINES; ISLAND; CHLAMYDIACEAE AB As part of conservation efforts between 1997 and 2001, more than 25% (332 animals) of the endangered Hawaiian monk seal (Monachus schauinslandi) population was sampled in the northwestern Hawaiian Islands. Serum samples were tested for antibodies to viruses, bacteria, and parasites known to cause morbidity and mortality in other marine mammal species. Antibodies were found to phocine herpesvirus-1 by using an enzyme-linked immunosorbent assay, but seropositive results were not confirmed by virus neutralization test. Antibodies to Leptospira bratislava, L. hardjo, L. icterohaemorrhagiae, and L. pomona were detected in seals from several sites with the microagglutination test. Antibodies to Brucella spp. were detected using 10 conventional serologic tests, but because of inconsistencies in test results and laboratories used, and the lack of validation by culture, the Brucella serology should be interpreted with caution. Antibodies to B. canis were not detected by card test. Chlamydophila abortus antibodies were detected by complement fixation (CF) test, and prevalence increased significantly as a function of age; the low sensitivity and specificity associated with the CF make interpretation of results difficult. Antibodies to Toxoplasma gondii and Dirofilaria immitis were rarely found. There was no serologic evidence of exposure to four morbilliviruses, influenza A virus, canine adenovirus, caliciviruses, or other selected viruses. Continuous surveillance provides a means to detect the introduction or emergence of these or other infectious diseases, but it is dependent on the development or improvement of diagnostic tools. Continued and improved surveillance are both needed as part of future conservation efforts of Hawaiian monk seals. C1 Wildlife Trust, New York, NY 10001 USA. Colorado State Univ, Dept Environm & Radiol Hlth Sci, Ft Collins, CO 80523 USA. Univ Hawaii, Joint Inst Marine & Atmospher Res, Honolulu, HI 96822 USA. Hubbs Sea World Res Inst, San Diego, CA 92109 USA. Oklahoma State Univ, Oklahoma Anim Dis Diagnost Lab, Stillwater, OK 74078 USA. Univ Calif Davis, Sch Vet Med, Lab Marine Mammal Immunol, Dept Pathol Microbiol & Immunol, Davis, CA 95616 USA. USDA ARS, ANRI PBESL, BARC EAST, Beltsville, MD 20705 USA. NOAA, Natl Marine Fisheries Serv, Pacific Isl Fisheries Sci Ctr, Honolulu, HI 96822 USA. RP Aguirre, AA (reprint author), Wildlife Trust, 460 W 34th St,17th Floor, New York, NY 10001 USA. EM aguirre@wildlifetrust.org NR 52 TC 25 Z9 27 U1 2 U2 29 PU WILDLIFE DISEASE ASSN, INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044-8897 USA SN 0090-3558 J9 J WILDLIFE DIS JI J. Wildl. Dis. PD APR PY 2007 VL 43 IS 2 BP 229 EP 241 PG 13 WC Veterinary Sciences SC Veterinary Sciences GA 177BW UT WOS:000247129600007 PM 17495307 ER PT J AU Smith, C Akujuobi, CM Hamory, P Kloesel, K AF Smith, Cary Akujuobi, Cajetan M. Hamory, Phil Kloesel, Kurt TI An approach to vibration analysis using wavelets in an application of aircraft health monitoring SO MECHANICAL SYSTEMS AND SIGNAL PROCESSING LA English DT Article ID EXTRACTION AB This paper explores an application of vibration detection in aircraft. Fatigue and breakdown of aircraft structure are common. Thus, efforts are made to constantly improve the monitoring and diagnostic systems for aircraft. These improvements have led to various approaches to fault monitoring in aircraft. In this work, the characteristic features of vibration signals are extracted from noise using the Haar, Daubechies, and Morlet wavelets. Then, detection of the vibration signal is achieved using the signal's scalogram information. Based on initial results, the wavelet-based algorithm is optimised through threshold experimentation. Additionally, the algorithm is verified using the simulation of a sinusoidal waveform and real flight data from the F-15B/836 research airplane. (c) 2006 Elsevier Ltd. All rights reserved. C1 Prairie View A&M Univ, Ctr Excellence Commun Syst Technol Res, Prairie View, TX USA. NASA Dryden Flight Res Ctr, Edwards AFB, CA USA. RP Akujuobi, CM (reprint author), Prairie View A&M Univ, Ctr Excellence Commun Syst Technol Res, Prairie View, TX USA. EM cmakujuobi@pvamu.edu NR 24 TC 26 Z9 29 U1 0 U2 3 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0888-3270 J9 MECH SYST SIGNAL PR JI Mech. Syst. Signal Proc. PD APR PY 2007 VL 21 IS 3 BP 1255 EP 1272 DI 10.1016/j.ymssp.2006.06.008 PG 18 WC Engineering, Mechanical SC Engineering GA 127ML UT WOS:000243590300006 ER PT J AU McGowan, KE Coe, MJ Schurch, M McBride, VA Galache, JL Edge, WRT Corbet, RHD Laycock, S Udalski, A Buckley, DAH AF McGowan, K. E. Coe, M. J. Schurch, M. McBride, V. A. Galache, J. L. Edge, W. R. T. Corbet, R. H. D. Laycock, S. Udalski, A. Buckley, D. A. H. TI X-ray bright sources in the Chandra Small Magellanic Cloud Wing Survey - detection of two new pulsars SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE X-rays : binaries; stars : emission-line, Be; Magellanic Clouds ID GRAVITATIONAL LENSING EXPERIMENT; SMC REGION; RADIO-CONTINUUM; BINARIES; CATALOG; PHOTOMETRY; PERIOD; VARIABILITY; BEHAVIOR; STARS AB We investigate the X-ray and optical properties of a sample of X-ray bright sources from the Small Magellanic Cloud (SMC) Wing Survey. We have detected two new pulsars with pulse periods of 65.8 s (CXOU J010712.6-723533) and 700 s (CXOU J010206.6-714115), and present observations of two previously known pulsars RX J0057.3-7325 (SXP101) and SAX J0103.2-7209 (SXP348). Our analysis has led to three new optical identifications for the detected pulsars. We find long-term optical periods for two of the pulsars, CXOU J010206.6-714115 and SXP101, of 267 and 21.9d, respectively. Spectral analysis of a subset of the sample shows that the pulsars have harder spectra than the other sources detected. By employing a quantile-based colour-colour analysis we are able to separate the detected pulsars from the rest of the sample. Using archival catalogues we have been able to identify counterparts for the majority of the sources in our sample. Combining this with our results from the temporal analysis of the Chandra data and archival optical data, the X-ray spectral analysis, and by determining the X-ray to optical flux ratios we present preliminary classifications for the sources. In addition to the four detected pulsars, our sample includes two candidate foreground stars, 12 probable active galactic nuclei, and five unclassified sources. C1 Univ Southampton, Sch Phys & Astron, Southampton SO17 1BJ, Hants, England. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Space Res Assoc, Xray Astrophys Lab, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Warsaw Observ, PL-00478 Warsaw, Poland. S African Astron Observ, ZA-7935 Cape Town, South Africa. So African Large Telescope Fdn, ZA-7935 Cape Town, South Africa. RP McGowan, KE (reprint author), Univ Southampton, Sch Phys & Astron, Southampton SO17 1BJ, Hants, England. EM kern@astro.soton.ac.uk NR 47 TC 17 Z9 17 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 1 PY 2007 VL 376 IS 2 BP 759 EP 770 DI 10.1111/j.1365-2966.2007.11468.x PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 157CY UT WOS:000245697400024 ER PT J AU Braun, SA Wu, LG AF Braun, Scott A. Wu, Liguang TI A numerical study of Hurricane Erin (2001). Part II: Shear and the organization of eyewall vertical motion SO MONTHLY WEATHER REVIEW LA English DT Article ID CONVECTIVE ADJUSTMENT SCHEME; TROPICAL CYCLONE INTENSITY; HIGH-RESOLUTION SIMULATION; RAPIDLY ROTATING VORTICES; AIR-SEA INTERACTION; BONNIE 1998; INNER-CORE; ICE-SCATTERING; LIGHTNING CHARACTERISTICS; BAROCLINIC VORTICES AB A high-resolution numerical simulation of Hurricane Erin (2001) is used to examine the organization of vertical motion in the eyewall and how that organization responds to a large and rapid increase in the environmental vertical wind shear and subsequent decrease in shear. During the early intensification period, prior to the onset of significant shear, the upward motion in the eyewall was concentrated in small-scale convective updrafts that formed in association with regions of Concentrated vorticity (herein termed mesovortices) with no preferred formation region around the eyewall. Asymmetric flow within the eve was weak. As the shear increased, an azimuthal wavenumber-1 asymmetry in storm structure developed with updrafts tending to occur on the downshear to downshear-left side of the eyewall. Continued intensification of the shear led to increasing wavenumber-1 asymmetry, large vortex tilt, and a change in eyewall structure and vertical motion organization. During this time, the eyewall structure was dominated by a vortex couplet with a cyclonic (anticyclonic) vortex on the downtilt-left (downtilt-right) side of the eyewall and strong asymmetric flow across the eye that led to strong mixing of eyewall vorticity into the eye. Upward motion was concentrated over an azimuthally broader region on the downtilt side of the eyewall, upstream of the cyclonic, vortex, where low-level environmental inflow converged with the asymmetric outflow from the eye. As the shear diminished, the vortex tilt and wavenumber-1 asymmetry decreased, while the organization of updrafts trended back toward that seen during the weak shear period. Based upon the results for the Erin case, as well as that for a similar simulation of Hurricane Bonnie (1998), a conceptual model is developed for the organization of vertical motion in the eyewall as a function of the strength of the vertical wind shear. In weak to moderate shear, higher wavenumber asymmetries associated with eyewall mesovortices dominate the wavenumber-1 asymmetry associated with the shear so that convective-scale updrafts form when the mesovortices move into the downtilt side of the eyewall and dissipate on the uptilt side. Under strong shear conditions, the wavenumber-1 asymmetry, characterized by a prominent vortex couplet in the eyewall, dominates the vertical motion organization so that mesoscale ascent (with embedded convection) occurs over an azimuthally broader region on the downtilt side of the eyewall. Further research is needed to determine if these results apply more generally. C1 NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RP Braun, SA (reprint author), NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Code 613-1, Greenbelt, MD 20771 USA. EM scott.a.braun@nasa.gov NR 58 TC 39 Z9 44 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 EI 1520-0493 J9 MON WEATHER REV JI Mon. Weather Rev. PD APR PY 2007 VL 135 IS 4 BP 1179 EP 1194 DI 10.1175/MWR3336.1 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 160ER UT WOS:000245924200002 ER PT J AU Emfietzoglou, D Nikjoo, H Pathak, A Sathish, N AF Emfietzoglou, D. Nikjoo, H. Pathak, A. Sathish, N. TI A comparison of secondary electron spectra from proton-impact ionization on water in the liquid and solid phases SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 15th International Conference on Ion Beam Modification of Materials CY SEP 18-22, 2006 CL Taormina, ITALY SP ST Microelect, IMM-CNR, MATIS CNR-INFM, Appl Mat, High Voltage Engn Europe, Axcelis, LPE-ETC, Hitec, Laser Source, 2M Strumenti, Varian, Univ Catania, Fac Sci DE water; dielectric theory; proton ionization; secondary electrons ID X-RAY-SCATTERING; CROSS-SECTIONS; ANGULAR-DISTRIBUTIONS; ENERGETIC PROTONS; VAPOR; MODEL AB Secondary electrons following direct ionization collisions are the main source of energy deposition in matter by almost any sufficiently energetic ion beam while integrals over their spectrum represent the dominant contribution to the inelastic mean free path and the electronic (collision) stopping power. In the present work we compare secondary electron spectra for fast but non-relativistic proton impact on liquid water and water ice in its hexagonal and amorphous form. The calculations are based on the first Born approximation employing semi-empirical dielectric response functions developed specifically for each form of water. The optical limit is obtained by a parametrization of all dielectric data representations, namely Im(epsilon), Re(epsilon) and Im(-1/epsilon), using a sum-rule constrained linear combination of Drude-type functions representing the various interband transitions. Extension to the energy-momentum plane is provided by appropriate dispersion relationships for the Drude coefficients which are consistent with the experimental data on the Bethe ridge of liquid water. A Platzman-plot analysis is used to examine the contribution of "soft" (dipole-like) and "hard" (binary-like) ionization collisions and their association to dielectric function properties. The present work is expected to contribute to a more realistic description of proton (and light ion) penetration and track formation in condensed water and other biological materials at the nanoscale level. (c) 2007 Elsevier B.V. All rights reserved. C1 Univ Hyderabad, Sch Phys, Hyderabad 500046, Andhra Pradesh, India. Univ Ioannina, Sch Med, Med Phys Lab, GR-45110 Ioannina, Greece. NASA, Lyndon B Johnson Space Ctr, Ctr Adv Space Studies, Houston, TX 77058 USA. RP Pathak, A (reprint author), Univ Hyderabad, Sch Phys, Hyderabad 500046, Andhra Pradesh, India. EM appsp@uohyd.ernet.in RI Natarajan, Sathish/C-1187-2012; J, H/C-1544-2012; Emfietzoglou, Dimitris/G-7168-2012 OI Natarajan, Sathish/0000-0001-7274-4576; NR 18 TC 1 Z9 1 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD APR PY 2007 VL 257 BP 609 EP 613 DI 10.1016/j.nimb.2007.01.049 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 163NB UT WOS:000246165500140 ER PT J AU Jones, WV Turner, K AF Jones, W. Vernon Turner, Kathy TI Fundamental physics and particle astrophysics in space in the USA SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Proceedings Paper CT 3rd International Conference on Particle and Fundamental Physics in Space CY APR 19-21, 2006 CL Beijing, PEOPLES R CHINA SP Chinese Minist Sci & Technol, Italian Natl Inst Nucl Phys, Italian Embassy Beijing, Japanese Soc Promot Space Sci, Beihang Univ ID MAGNETIC SPECTROMETER AMS AB This paper presents a high level view of some key fundamental physics and particle astrophysics investigations underway or planned by the U.S. This scope precludes some of the highest priorities of the Agencies, and some projects within scope are not discussed because of space limitations or the fact that they were presented independently. C1 NASA, Sci Miss Directorate, Div Astrophys, Washington, DC 20546 USA. US DOE, Off High Energy Phys, Washington, DC 20585 USA. RP Jones, WV (reprint author), NASA, Sci Miss Directorate, Div Astrophys, DH-1000, Washington, DC 20546 USA. NR 8 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD APR PY 2007 VL 166 BP 3 EP 11 DI 10.1016/j.nuclphysbps.2006.12.065 PG 9 WC Physics, Particles & Fields SC Physics GA 156FT UT WOS:000245634200002 ER PT J AU Yamamoto, A Abe, K Fuke, H Haino, S Hams, T Kim, K Lee, MH Makida, Y Matsuda, S Mitchell, JW Moiseev, A Nishimura, J Nozaki, M Orito, R Orito, S Ormes, JF Sakai, K Sanuki, T Sasaki, M Seo, ES Shikaze, Y Streitmatter, RE Suzuki, J Tanaka, K Thakur, N Yamagami, T Yoshida, T Yoshimura, K AF Yamamoto, A. Abe, K. Fuke, H. Haino, S. Hams, T. Kim, K. Lee, M. H. Makida, Y. Matsuda, S. Mitchell, J. W. Moiseev, A. Nishimura, J. Nozaki, M. Orito, R. Orito, S. Ormes, J. F. Sakai, K. Sanuki, T. Sasaki, M. Seo, E. S. Shikaze, Y. Streitmatter, R. E. Suzuki, J. Tanaka, K. Thakur, N. Yamagami, T. Yoshida, T. Yoshimura, K. TI The BESS program SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Proceedings Paper CT 3rd International Conference on Particle and Fundamental Physics in Space CY APR 19-21, 2006 CL Beijing, PEOPLES R CHINA SP Chinese Minist Sci & Technol, Italian Natl Inst Nucl Phys, Italian Embassy Beijing, Japanese Soc Promot Space Sci, Beihang Univ ID COSMIC-RAY ANTIPROTONS; MOUNTAIN ALTITUDE; SOLAR MINIMUM; MUON SPECTRA; SPECTROMETER; FLUX; HELIUM; PROTON; ANTIHELIUM AB The Balloon-Born Experiment with a Superconducting Spectrometer (BESS) has measured cosmic-ray spectra blow 1 TeV and searched for antiparticle of novel cosmic origin. The BESS program is extended to long duration balloon (LDB) flights in Antarctica (BESS-Polar) aiming at unprecedented sensitivity to search for primordial antiparticles. This report describes recent results from BESS and the progress in the BESS-Polar program. C1 High Energy Accelerator Res Org, Tsukuba, Ibaraki 3050801, Japan. Kobe Univ, Kobe, Hyogo 657850, Japan. Inst Space & Astronaut Sci, JAXA, Sagamihara, Kanagawa 2298510, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, College Pk, MD 20742 USA. Univ Tokyo, Bunkyo Ku, Tokyo 1130044, Japan. Univ Denver, Denver, CO 80208 USA. RP Yamamoto, A (reprint author), High Energy Accelerator Res Org, Tsukuba, Ibaraki 3050801, Japan. OI Seo, Eun-Suk/0000-0001-8682-805X NR 34 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD APR PY 2007 VL 166 BP 62 EP 67 DI 10.1016/j.nuclphysbps.2006.12.092 PG 6 WC Physics, Particles & Fields SC Physics GA 156FT UT WOS:000245634200010 ER PT J AU Takizawa, Y Ebisuzaki, T Kawasaki, Y Sato, M Bertaina, ME Ohmori, H Takahashi, Y Kajino, F Nagano, M Sakaki, N Inoue, N Ikeda, H Arai, Y Takahashi, Y Murakami, T Adams, JH AF Takizawa, Y. Ebisuzaki, T. Kawasaki, Y. Sato, M. Bertaina, M. E. Ohmori, H. Takahashi, Y. Kajino, F. Nagano, M. Sakaki, N. Inoue, N. Ikeda, H. Arai, Y. Takahashi, Y. Murakami, T. Adams, James H. CA JEM-EUSO Collaboration TI JEM-EUSO: Extreme universe space observatory on JEM/ISS SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Proceedings Paper CT 3rd International Conference on Particle and Fundamental Physics in Space CY APR 19-21, 2006 CL Beijing, PEOPLES R CHINA SP Chinese Minist Sci & Technol, Italian Natl Inst Nucl Phys, Italian Embassy Beijing, Japanese Soc Promot Space Sci, Beihang Univ ID COSMIC-RAY SPECTRUM; WAVES AB EUSO is a super-wide field UV telescope to detect Ultra-High Energy Cosmic-Rays (UHECRs) with energy above 10(20) eV. It is attached to the International Space Station (ISS) and observes fluorescence photons emitted by giant air showers produced by UHECR. The three dimensional development of the shower is reconstructed from a series of images of the shower. Phase-A study of EUSO under the European Space Agency (ESA) has successfully finished in July 2004. The phase-B study, however, has been postponed for a long time because of financial problems in ESA and Italy. Then, Japanese and U.S. teams re-defined EUSO as a mission attached to the Japanese Experiment Module/Exposure Facility of ISS. They renamed it as JEM-EUSO and started the preparation targeting the launch in 2012 in the framework of second phase of JEM/EF utilization. The outline of the mission is presented. C1 RIKEN, Wako, Saitama 3510198, Japan. Konan Univ, Higashinada Ku, Kobe, Hyogo 6588501, Japan. Fukui Univ Technol, Fukui 9108505, Japan. Aoyama Gakuin Univ, Sagamihara, Kanagawa 2298558, Japan. Saitama Univ, Sakura Ku, Urawa, Saitama 3388570, Japan. JAXA, ISAS, Sagamihara, Kanagawa 2298510, Japan. KEK, Tsukuba, Ibaraki 3050801, Japan. Tohoku Univ, Aoba Ku, Sendai, Miyagi 9808578, Japan. Kanazawa Univ, Kanazawa, Ishikawa 9201192, Japan. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Takizawa, Y (reprint author), RIKEN, 2-1 Hirosawa, Wako, Saitama 3510198, Japan. OI Bertaina, Mario Edoardo/0000-0003-1069-1397 NR 10 TC 6 Z9 6 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD APR PY 2007 VL 166 BP 72 EP 76 DI 10.1016/j.nuclphysbps.2006.12.007 PG 5 WC Physics, Particles & Fields SC Physics GA 156FT UT WOS:000245634200012 ER PT J AU Marshall, FE AF Marshall, Francis E. TI Swift - The first 100 Gamma-Ray Bursts SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Proceedings Paper CT 3rd International Conference on Particle and Fundamental Physics in Space CY APR 19-21, 2006 CL Beijing, PEOPLES R CHINA SP Chinese Minist Sci & Technol, Italian Natl Inst Nucl Phys, Italian Embassy Beijing, Japanese Soc Promot Space Sci, Beihang Univ ID AFTERGLOW; REDSHIFT AB Gamma Ray Bursts are the largest explosions in the Universe, and the recently launched Swift mission is a multi-wavelength observatory that has greatly expanded our ability to study them. Swift's wide-field gamma-ray camera is detecting about 100 bursts per year that are quickly viewed with sensitive X-ray and UV/optical telescopes on the observatory. Positions are rapidly released to the world to enable ground-based observations. Results from the first year of observations will be presented. The mystery of short GRBs has been solved, very high redshift bursts discovered, and enormous X-ray flares found in afterglows. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Marshall, FE (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD APR PY 2007 VL 166 BP 116 EP 119 DI 10.1016/j.nuclphysbps.2006.12.009 PG 4 WC Physics, Particles & Fields SC Physics GA 156FT UT WOS:000245634200018 ER PT J AU De Angelis, G Badavi, FF Clem, JM Blattnig, SR Clowdsley, MS Nealy, JE Tripathi, RK Wilson, JW AF De Angelis, G. Badavi, F. F. Clem, J. M. Blattnig, S. R. Clowdsley, M. S. Nealy, J. E. Tripathi, R. K. Wilson, J. W. TI Modeling of the Lunar Radiation Environment SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Proceedings Paper CT 3rd International Conference on Particle and Fundamental Physics in Space CY APR 19-21, 2006 CL Beijing, PEOPLES R CHINA SP Chinese Minist Sci & Technol, Italian Natl Inst Nucl Phys, Italian Embassy Beijing, Japanese Soc Promot Space Sci, Beihang Univ ID GALACTIC COSMIC-RAYS; INTERPLANETARY SPACE; SOLAR-FLARES; ACCELERATION; PROPAGATION AB In view of manned missions targeted to the Moon, for which radiation exposure is one of the greatest challenges to be tackled; it is of fundamental importance to have available a tool, which allows the determination of the particle flux and spectra at any time and at any point of the lunar surface. With this goal in mind, a new model of the Moon's radiation environment due to Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE) has been developed. Primary particles reach the lunar surface, and are transported all throughout the subsurface layers, with backscattering patterns taken into account. The surface itself has been modeled as regolith and bedrock, with composition taken from the results of the instruments flown on the Apollo missions. Subsurface environments like lava tubes have been considered in the analysis. Particle transport has been performed with both deterministic and Monte Carlo codes with an adaptation for planetary surface geometry. Results are given in terms of fluxes, doses and LET, for most kinds of particles for various kinds of soil and rock chemical compositions. C1 Ist Super Sanita, I-00161 Rome, Italy. Christopher Newport Univ, Newport News, VA 23606 USA. Univ Delaware, Bartol Res Inst, Newark, DE USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Old Dominion Univ, Norfolk, VA 23508 USA. RP De Angelis, G (reprint author), Ist Super Sanita, Viale Regina Elena 299, I-00161 Rome, Italy. EM giovanni.deangelis@iss.it NR 72 TC 8 Z9 9 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD APR PY 2007 VL 166 BP 169 EP 183 DI 10.1016/j.nuclphysbps.2006.12.034 PG 15 WC Physics, Particles & Fields SC Physics GA 156FT UT WOS:000245634200026 ER PT J AU De Angelis, G Badavi, FF Blattnig, SR Clowdsley, MS Nealy, JE Qualls, GD Singleterry, RC Tripathi, RK Wilson, JW AF De Angelis, G. Badavi, F. F. Blattnig, S. R. Clowdsley, M. S. Nealy, J. E. Qualls, G. D. Singleterry, R. C. Tripathi, R. K. Wilson, J. W. TI Modeling of the Martian Environment for Radiation Analysis SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Proceedings Paper CT 3rd International Conference on Particle and Fundamental Physics in Space CY APR 19-21, 2006 CL Beijing, PEOPLES R CHINA SP Chinese Minist Sci & Technol, Italian Natl Inst Nucl Phys, Italian Embassy Beijing, Japanese Soc Promot Space Sci, Beihang Univ ID GALACTIC COSMIC-RAYS; MARS ATMOSPHERIC DYNAMICS; GENERAL-CIRCULATION MODEL; SOUTH POLAR-CAP; INTERPLANETARY SPACE; GUSEV CRATER; NORTHERN-HEMISPHERE; MERIDIANI-PLANUM; SPIRIT ROVER; SOLAR-FLARES AB Results for the radiation environment to be found on the planet Mars due to Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE) has been obtained. Primary particle environments computed for Martian conditions are transported within the Mars atmosphere, modeled in a time-dependent way in terms of density, pressure, and temperature vs. altitude, down to the surface, with topography and backscattering patterns taken into account. The atmospheric chemical and isotopic composition has been modeled over results from the in-situ Viking Lander measurements for both major and minor components. The surface topography has been determined by using a model based on the data provided by the Mars Orbiter Laser Altimeter (MOLA) instrument on board the Mars Global Surveyor (MGS) spacecraft. The surface itself has been modeled in both the dry ('regolith') and volatile components. Mars regolith composition has been modeled based on the measurements obtained with orbiter and lander spacecraft from which an average composition has been derived. The volatile inventory properties, both in the regolith and in the seasonal and perennial polar caps, has been taken into account by modeling the deposition of volatiles and its variations with geography and time all throughout the Martian year, from results from imaging data of orbiter spacecraft. Results are given in terms of fluxes, doses and LET, for most kinds of particles, namely protons, neutrons, alpha particles, heavy ions, pions, and unions for various soil compositions. C1 Ist Super Sanita, I-00161 Rome, Italy. Christopher Newport Univ, Newport News, VA 23606 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Old Dominion Univ, Norfolk, VA 23508 USA. RP De Angelis, G (reprint author), Ist Super Sanita, Viale Regina Elena 299, I-00161 Rome, Italy. EM giovanni.deangelis@iss.it NR 79 TC 6 Z9 6 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD APR PY 2007 VL 166 BP 184 EP 202 DI 10.1016/j.nuclphysbps.2006.12.035 PG 19 WC Physics, Particles & Fields SC Physics GA 156FT UT WOS:000245634200027 ER PT J AU Banerdt, WB Chui, T Griggs, CE Herrin, ET Nakamura, Y Paik, HJ Penanen, K Rosenbaum, D Teplitz, VL Young, J AF Banerdt, W. Bruce Chui, Talso Griggs, Cornelius E. Herrin, Eugene T. Nakamura, Yosio Paik, Ho Jung Penanen, Konstantin Rosenbaum, Doris Teplitz, Vigdor L. Young, Joseph TI Using the Moon as a low-noise seismic detector for strange quark nuggets SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Proceedings Paper CT 3rd International Conference on Particle and Fundamental Physics in Space CY APR 19-21, 2006 CL Beijing, PEOPLES R CHINA SP Chinese Minist Sci & Technol, Italian Natl Inst Nucl Phys, Italian Embassy Beijing, Japanese Soc Promot Space Sci, Beihang Univ ID SEISMOGRAPHIC STATION REPORTS; UNEXPLAINED SETS; EARLY UNIVERSE; MATTER; NUCLEARITES; STARS; CONSISTENT; SEARCHES; PASSAGE AB Strange quark matter made of up; down and strange quarks has been postulated by Witten [1]. Strange quark matter would be nearly charge neutral and would have density of nuclear matter (10(14) gm/cm(3)). Witten also suggested that nuggets of strange quark matter, or strange quark nuggets (SQNs), could have formed shortly after the Big Bang, and that they would be viable candidates for cold dark matter. As suggested by de Rujula and Glashow (2), an SQN may pass through a celestial body releasing detectable seismic energy along a straight line. The Moon, being much quieter seismically than the Earth, would be a favorable place to search for such events. We review previous searches for SQNs to illustrate the parameter space explored by using the Moon as a low-noise detector of SQNs. We also discuss possible detection schemes using a single seismometer, and using an International Lunar Seismic Network. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. So Methodist Univ, Dept Geol, Dallas, TX 75275 USA. Univ Texas, Inst Geophys, Austin, TX 78759 USA. So Methodist Univ, Dept Phys, Dallas, TX 75275 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Chui, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 31 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD APR PY 2007 VL 166 BP 203 EP 208 DI 10.1016/j.nuclphysbps.2006.12.045 PG 6 WC Physics, Particles & Fields SC Physics GA 156FT UT WOS:000245634200028 ER PT J AU Griggs, CE Paik, HJ Chui, T Penanen, K Young, J AF Griggs, Cornelius E. Paik, Ho Jung Chui, Talso Penanen, Konstantin Young, Joseph TI Seismometer for strange quark nugget search and for lunar science studies SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Proceedings Paper CT 3rd International Conference on Particle and Fundamental Physics in Space CY APR 19-21, 2006 CL Beijing, PEOPLES R CHINA SP Chinese Minist Sci & Technol, Italian Natl Inst Nucl Phys, Italian Embassy Beijing, Japanese Soc Promot Space Sci, Beihang Univ AB Because the Moon is much quieter seismically than the Earth, science to be performed on the Moon using seismology is currently limited by the best available seismometer. We describe the developrnent of a lunar seismometer with sensitivity at least 100 times higher than current state of the art. Analysis of the fundamental noise of this seismometer shows that at frequency below similar to 1 Hz the noise will be dominated by Brownian motion of the test mass. Above similar to 1 Hz, it will be dominated by thermal noise in the electronic readout. The electronic noise corresponds to similar to 10(-13) in Hz(-1/2). A way to reduce the Brownian motion noise of the test mass using electrostatic force is also discussed. C1 Univ Maryland, Dept Phys, College Pk, MD 20742 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Paik, HJ (reprint author), Univ Maryland, Dept Phys, College Pk, MD 20742 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD APR PY 2007 VL 166 BP 209 EP 213 DI 10.1016/j.nuclphysbps.2006.12.012 PG 5 WC Physics, Particles & Fields SC Physics GA 156FT UT WOS:000245634200029 ER PT J AU Jones, WV AF Jones, W. Vernon TI Recent developments in scientific research ballooning SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Proceedings Paper CT 3rd International Conference on Particle and Fundamental Physics in Space CY APR 19-21, 2006 CL Beijing, PEOPLES R CHINA SP Chinese Minist Sci & Technol, Italian Natl Inst Nucl Phys, Italian Embassy Beijing, Japanese Soc Promot Space Sci, Beihang Univ AB The National Aeronautics and Space Administration (NASA) Balloon Program is committed to meeting the need for extended duration scientific investigations by providing advanced balloon vehicles and support systems. A sea change in ballooning capability occurred with the inauguration of 8 - 20 day flights around Antarctica in the early 1990's. The attainment of 28 - 31 day, flights and a record-breaking 42-day flight in, respectively, two and three circumnavigations of the continent has greatly increased the expectations of the scientific users. A new super-pressure balloon is currently under development for future flights of 60 - 100 days at any latitude, which would bring another sea change in scientific research ballooning. C1 NASA Headquarters, Sci Mission Directorate, Div Astrophys, Washington, DC 20546 USA. RP Jones, WV (reprint author), NASA Headquarters, Sci Mission Directorate, Div Astrophys, DH 000, Washington, DC 20546 USA. NR 11 TC 0 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD APR PY 2007 VL 166 BP 217 EP 222 DI 10.1016/j.nuclphysbps.2006.12.064 PG 6 WC Physics, Particles & Fields SC Physics GA 156FT UT WOS:000245634200030 ER PT J AU Wang, X Wang, B Bos, PJ McManamon, PF Pouch, JJ Miranda, FA Anderson, JE AF Wang, Xinghua Wang, Bin Bos, Philip J. McManamon, Paul F. Pouch, John J. Miranda, Felix A. Anderson, James E. TI Modeling and performance limits of a large aperture high-resolution wavefront control system based on a liquid crystal spatial light modulator SO OPTICAL ENGINEERING LA English DT Article DE liquid crystal; spatial light modulator; aberration correction; diffractive optical device ID OPTICS AB The aberration introduced by the primary optical element of a lightweight large aperture telescope can be corrected with a diffractive optical element called the liquid crystal spatial light modulator. Such aberration is usually very large, which makes the design and modeling of such a system difficult. A method to analyze the system is introduced, and the performance limitation of the system is studied through extensive modeling. An experimental system is demonstrated to validate the analysis. The connection between the modeling data and the experimental data is given. (c) 2007 Society of Photo-Optical Instrumentation Engineers. C1 Kent State Univ, Inst Liquid Crystal, Kent, OH 44242 USA. USAF, Res Lab, Dayton, OH 45424 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Hana Microdisplay Technol Inc, Twinsburg, OH 44087 USA. RP Wang, X (reprint author), Kent State Univ, Inst Liquid Crystal, Kent, OH 44242 USA. EM pbos@kent.edu NR 24 TC 13 Z9 15 U1 0 U2 4 PU SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 EI 1560-2303 J9 OPT ENG JI Opt. Eng. PD APR PY 2007 VL 46 IS 4 AR 044001 DI 10.1117/1.2730485 PG 17 WC Optics SC Optics GA 166BI UT WOS:000246351600022 ER PT J AU Savchenkov, AA Matsko, AB Strekalov, D Ilchenko, VS Maleki, L AF Savchenkov, Anatoliy A. Matsko, Andrey B. Strekalov, Dmitry Ilchenko, Vladimir S. Maleki, Lute TI Photorefractive damage in whispering gallery resonators SO OPTICS COMMUNICATIONS LA English DT Article ID OPTOELECTRONIC MICROWAVE-OSCILLATOR; MODE RESONATORS; WAVE RECEIVER; MODULATOR; FILTERS AB We report on a study of optical properties of whispering gallery mode resonators made out of as-grown nominally pure lithium niobate crystals. We have observed a surprising dynamic modification of the spectrum of the resonators illuminated with the near infrared light. We attribute this effect to the photorefractive damage of the resonator host material. (c) 2006 Elsevier B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Matsko, AB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Andrey.Matsko@jpl.nasa.gov RI Matsko, Andrey/A-1272-2007 NR 17 TC 5 Z9 5 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0030-4018 J9 OPT COMMUN JI Opt. Commun. PD APR 1 PY 2007 VL 272 IS 1 BP 257 EP 262 DI 10.1016/j.optcom.2006.11.029 PG 6 WC Optics SC Optics GA 143MU UT WOS:000244727200042 ER PT J AU Weber, AL AF Weber, Arthur L. TI The sugar model: Autocatalytic activity of the triose-ammonia reaction SO ORIGINS OF LIFE AND EVOLUTION OF BIOSPHERES LA English DT Article DE sugar chemistry; triose; sugar-ammonia reaction; catalysis; autocatalysis; Maillard reaction; prebiotic chemistry; origin of life ID MILD AQUEOUS CONDITIONS; MAILLARD REACTION; ORGANIC-COMPOUNDS; EARLY EARTH; PRIMITIVE EARTH; CARBON; ATMOSPHERE; FORMALDEHYDE; REDUCTION; ENERGY AB Reaction of triose sugars with ammonia under anaerobic conditions yielded autocatalytic products. The autocatalytic behavior of the products was examined by measuring the effect of the crude triose-ammonia reaction product on the kinetics of a second identical triose-ammonia reaction. The reaction product showed autocatalytic activity by increasing both the rate of disappearance of triose and the rate of formation of pyruvaldehyde, the product of triose dehydration. This synthetic process is considered a reasonable model of origin-of-life chemistry because it uses plausible prebiotic substrates, and resembles modem biosynthesis by employing the energized carbon groups of sugars to drive the synthesis of autocatalytic molecules. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. RP Weber, AL (reprint author), NASA, Ames Res Ctr, SETI Inst, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM aweber@mail.arc.nasa.gov NR 40 TC 24 Z9 24 U1 1 U2 13 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0169-6149 J9 ORIGINS LIFE EVOL B JI Orig. Life Evol. Biosph. PD APR PY 2007 VL 37 IS 2 BP 105 EP 111 DI 10.1007/s11084-006-9059-9 PG 7 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 157VY UT WOS:000245750700001 PM 17225954 ER PT J AU Hazen, RM Deamer, DW AF Hazen, Robert M. Deamer, David W. TI Hydrothermal reactions of pyruvic acid: Synthesis, selection, and self-assembly of amphiphilic molecules SO ORIGINS OF LIFE AND EVOLUTION OF BIOSPHERES LA English DT Article DE pyruvic acid; hydrothermal system; Murchison carbonaceous chondrite; self-assembly; amphiphile ID SYSTEMS AB Selection and self-assembly of organic compounds in aqueous phases must have been a primary process leading to emergent molecular complexity and ultimately to the origin of life. Facile reactions of pyruvic acid under hydrothermal conditions produce a complex mixture of larger organic molecules, some of which are amphiphiles that readily self-assemble into cell-sized vesicular structures. Chemical characterization of major components of this mixture reveals similarities to the suite of organic compounds present in the Murchison carbonaceous chondrite, some of whose molecules also self-assemble into membranous vesicles. Physical properties of the products are thus relevant to understanding the prebiotic emergence of molecular complexity. These results suggest that a robust family of prebiotic reaction pathways produces similar products over a range of geochemical and astrochemical environments. C1 Carnegie Inst Washington, Washington, DC 20015 USA. NASA, Astrobiol Inst, Washington, DC 20015 USA. Univ Calif Santa Cruz, Dept Chem & Biochem, Santa Cruz, CA 95064 USA. RP Hazen, RM (reprint author), Carnegie Inst Washington, 5251 Broad Branch Rd NW, Washington, DC 20015 USA. EM rhazen@gl.ciw.edu NR 27 TC 11 Z9 12 U1 2 U2 20 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0169-6149 J9 ORIGINS LIFE EVOL B JI Orig. Life Evol. Biosph. PD APR PY 2007 VL 37 IS 2 BP 143 EP 152 DI 10.1007/s11084-006-9027-4 PG 10 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 157VY UT WOS:000245750700004 PM 17136431 ER PT J AU Malkova, N Ning, CZ AF Malkova, N. Ning, C. Z. TI Band structure and optical properties of wurtzite semiconductor nanotubes SO PHYSICAL REVIEW B LA English DT Article ID NITRIDE NANOTUBES; SURFACE; GAN AB We develop a comprehensive theoretical model for the band structure of single-crystal faceted nanotubes of wurtzite semiconductors based on the tight-binding approach. We focus on the GaN nanotube grown along the [0001] direction and surrounded by the equivalent surfaces {1 (1) over bar 100}. We first calculate the band structure of the wurtzite slab of finite thickness grown along the axis [1 (1) over bar 00]. We show that dangling bonds on two surfaces of the slab cause surface bands, which form the conduction and valence bands of the slab. Analyzing the symmetry of the single-crystal faceted nanotubes, we conclude that their band structure can be calculated from that of the slab with the help of cyclic boundary conditions. We show that the spectrum of the nanotubes depends both on the thickness of nanotube walls and on the radius. We further study the absorption coefficient of the nanotubes. We demonstrate that, with decreasing wall thickness, the contribution of surface states to the absorption spectrum becomes more pronounced. C1 Arizona State Univ, NASA, Ames Res Ctr, Tempe, AZ 85287 USA. Arizona State Univ, Ctr Nanophoton, Tempe, AZ 85287 USA. Arizona State Univ, Dept Elect Engn, Tempe, AZ 85287 USA. RP Malkova, N (reprint author), Arizona State Univ, NASA, Ames Res Ctr, Tempe, AZ 85287 USA. EM nmalkova@mail.arc.nasa.gov; cning@asu.edu RI Ning, C. Z./D-4699-2009 OI Ning, C. Z./0000-0003-4583-8889 NR 22 TC 12 Z9 12 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD APR PY 2007 VL 75 IS 15 AR 155407 DI 10.1103/PhysRevB.75.155407 PG 7 WC Physics, Condensed Matter SC Physics GA 162GQ UT WOS:000246075300103 ER EF