FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Fu, LL AF Fu, Lee-Lueng TI Pathways of eddies in the South Atlantic Ocean revealed from satellite altimeter observations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MESOSCALE VARIABILITY; AGULHAS EDDIES; SEA-LEVEL; TOPEX/POSEIDON; DYNAMICS AB The majority of the kinetic energy of ocean currents is contained in the mesoscale eddies. The pathways of ocean eddies, which are the "weather'' of ocean circulation, are mapped from space using a decade-long record of sea surface height measured by two simultaneously flying satellite radar altimeters. The speed and direction of the propagation of eddies in the South Atlantic Ocean are presented in the paper. The patterns of the eddy propagation velocity reveal the effects of the interaction between mean flow and eddies with strong influence of bottom topography. The information describes a unique property of the ocean general circulation and serves as a basis for testing ocean models. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fu, LL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM llf@pacific.jpl.nasa.gov NR 19 TC 32 Z9 32 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 JUL 22 PY 2006 VL 33 IS 14 AR L14610 DI 10.1029/2006GL026245. PG 5 WC Geosciences, Multidisciplinary SC Geology GA 071DI UT WOS:000239577800003 ER PT J AU Oberheide, J Offermann, D Russell, JM Mlynczak, MG AF Oberheide, J. Offermann, D. Russell, J. M., III Mlynczak, M. G. TI Intercomparison of kinetic temperature from 15 mu m CO2 limb emissions and OH*(3,1) rotational temperature in nearly coincident air masses: SABER, GRIPS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MIDDLE; LIDAR AB Three years (2003-2005) of kinetic temperatures measured by the Sounding the Atmosphere using Broadband Emission Radiometry (SABER) instrument on board the TIMED satellite are compared to OH*(3,1) rotational temperatures measured by the Ground Based Infrared P-Branch Spectrometer (GRIPS) located at 7.2 degrees E, 51.3 degrees N in Wuppertal, Germany. Comparisons are confined to nearly coincident air masses (miss distance: similar to 600 km, miss time: 30 minutes). OH*(3,1) rotational temperatures are systematically higher by 7.5 K than OH equivalent SABER temperatures derived from 15 mu m CO2 limb emissions which is just within the combined error bars. The bias is independent of year and season thus providing additional confidence into allocating the mean altitude of the OH* emission layer to a constant value of 87 km for long-term trend analyses. C1 Univ Wuppertal, Dept Phys, D-42097 Wuppertal, Germany. Hampton Univ, Dept Phys, Ctr Atmospher Sci, Hampton, VA 23668 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Oberheide, J (reprint author), Univ Wuppertal, Dept Phys, Gauss Str 20, D-42097 Wuppertal, Germany. EM joberh@uni-wuppertal.de RI Oberheide, Jens/C-6156-2011; Mlynczak, Martin/K-3396-2012 OI Oberheide, Jens/0000-0001-6721-2540; NR 13 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 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 22 PY 2006 VL 33 IS 14 AR L14811 DI 10.1029/2006GL026439 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 071DI UT WOS:000239577800005 ER PT J AU Chuss, DT Wollack, EJ Moseley, SH Novak, G AF Chuss, David T. Wollack, Edward J. Moseley, S. Harvey Novak, Giles TI Interferometric polarization control SO APPLIED OPTICS LA English DT Article ID POLARIMETER; CAMERA AB We develop the Jones and Mueller matrices for structures that allow control of the path length difference between two linear orthogonal polarizations and consider the effect of placing multiple devices in series. Specifically, we find that full polarization modulation (measurement of Stokes Q, U, and V) call be achieved by placing two Such modulators in series if the relative angles of the beam-splitting grids with respect to the analyzer orientation are appropriately chosen. Such a device has Several potential advantages over a spinning wave plate Modulator for measuring astronomical polarization in the far infrared through millimeter: (i) The use of small, linear motions eliminates the need for cryogenic rotational hearings: (ii) the phase flexibility allows measurement of circular as well as linear polarization: and (iii) this architecture allows for both multiwavelength and broadband modulation. We also present initial laboratory results. (c) 2006 Optical Society of America. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. RP Chuss, DT (reprint author), NASA, Goddard Space Flight Ctr, Code 665, Greenbelt, MD 20771 USA. EM David.T.Chuss@nasa.gov RI Moseley, Harvey/D-5069-2012; Wollack, Edward/D-4467-2012 OI Wollack, Edward/0000-0002-7567-4451 NR 20 TC 22 Z9 22 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUL 20 PY 2006 VL 45 IS 21 BP 5107 EP 5117 DI 10.1364/AO.45.005107 PG 11 WC Optics SC Optics GA 065TE UT WOS:000239181600006 PM 16826249 ER PT J AU Shaklan, SB Green, JJ AF Shaklan, Stuart B. Green, Joseph J. TI Reflectivity and optical surface height requirements in a broadband coronagraph. 1. Contrast floor due to controllable spatial frequencies SO APPLIED OPTICS LA English DT Article ID LIGHT MODULATORS; AMPLITUDE; PHASE AB We derive the broadband contrast floor in a coronagraphic telescope having nonideal optical surfaces. We consider only fundamental spatial frequencies within the control bandwidth of the coronagraph's deformable mirror. Cross terms arising from the beating of spatial frequencies beyond the deformable mirror control bandwidth will be considered in a second paper. Two wavefront control systems are analyzed: a zero-path difference Michelson interferometer with two deformable mirrors at a pupil image, and a sequential pair of deformable mirrors with one placed at a pupil image. We derive requirements on Optical Surface figure and reflectivity uniformity for both cases. (c) 2006 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shaklan, SB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM stuart.shaklan@jpl.nasa.gov NR 15 TC 52 Z9 52 U1 1 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUL 20 PY 2006 VL 45 IS 21 BP 5143 EP 5153 DI 10.1364/AO.45.005143 PG 11 WC Optics SC Optics GA 065TE UT WOS:000239181600009 PM 16826252 ER PT J AU Sambruna, RM Markwardt, CB Mushotzky, RF Tueller, J Hartman, R Brandt, WN Schneider, DP Falcone, A Cucchiara, A Aller, MF Aller, HD Torniainen, I Tavecchio, F Maraschi, L Gliozzi, M Takahashi, T AF Sambruna, R. M. Markwardt, C. B. Mushotzky, R. F. Tueller, J. Hartman, R. Brandt, W. N. Schneider, D. P. Falcone, A. Cucchiara, A. Aller, M. F. Aller, H. D. Torniainen, I. Tavecchio, F. Maraschi, L. Gliozzi, M. Takahashi, T. TI Discovery of an extreme MeV blazar with the Swift burst alert telescope SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; quasars : individual (J0746.3+2548); X-rays : galaxies ID SPECTRAL ENERGY-DISTRIBUTIONS; DIGITAL-SKY-SURVEY; SOFT-X-RAY; ACTIVE GALACTIC NUCLEI; HIGH-REDSHIFT QUASARS; BL-LACERTAE OBJECTS; LUMINOSITY FUNCTION; RADIO QUASARS; 3C 273; EMISSION AB The Burst Alert Telescope ( BAT) on board Swift detected bright emission from 15 - 195 keV from the source SWIFT J0746.3+2548 (J0746 in the following), identified with the optically faint (R similar to 19), z = 2.979 quasar SDSS J074625.87+244901.2. Here we present Swift and multiwavelength observations of this source. The X-ray emission from J0746 is variable on timescales of hours to weeks in 0.5-8 keV and of a few months in 15-195 keV, but there is no accompanying spectral variability in the 0.5-8 keV band. There is a suggestion that the BAT spectrum, initially very hard (photon index Gamma similar to 0.7), steepened to Gamma similar to 1.3 in a few months, together with a decrease of the 15-195 keV flux by a factor similar to 2. The 0.5-8 keV continuum is well described by a power law with Gamma similar to 1.3 and spectral flattening below 1 keV. The latter can be described with a column density in excess of the Galactic value with intrinsic column density N-H(z) similar to 10(22) cm(-2), or with a flatter power law, implying a sharp (Delta Gamma greater than or similar to 1) break across 16 keV in the quasar's rest frame. The spectral energy distribution of J0746 is double-humped, with the first component peaking at IR wavelengths and the second component at MeV energies. These properties suggest that J0746 is a blazar with high gamma-ray luminosity and low peak energy (MeV), stretching the blazar sequence to an extreme. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Helsinki Univ Technol, Metsahovi Radio Observ, FIN-02540 Kylmala, Finland. Osserv Astron Brera, Milan, Italy. George Mason Univ, Dept Phys & Astron, Fairfax, VA 22030 USA. George Mason Univ, Sch Computat Sci, Fairfax, VA 22030 USA. Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. RP Sambruna, RM (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Tueller, Jack/D-5334-2012; Brandt, William/N-2844-2015 OI Brandt, William/0000-0002-0167-2453 NR 60 TC 28 Z9 28 U1 0 U2 2 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 JUL 20 PY 2006 VL 646 IS 1 BP 23 EP 35 DI 10.1086/504838 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072AL UT WOS:000239644900004 ER PT J AU Gliozzi, M Sambruna, RM Jung, I Krawczynski, H Horan, D Tavecchio, F AF Gliozzi, M. Sambruna, R. M. Jung, I. Krawczynski, H. Horan, D. Tavecchio, F. TI Long-term X-ray and TeV variability of MRK 501 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : jets; galaxies : nuclei; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; BL-LAC OBJECTS; GAMMA-RAYS; SPECTRAL EVOLUTION; TIMING-EXPLORER; MARKARIAN 501; XMM-NEWTON; BLAZAR MARKARIAN-421; SEYFERT-1 GALAXIES; TELESCOPE SYSTEM AB We present X-ray observations of the nearby TeV blazar Mrk 501 obtained with RXTE during 1997, 1998, 1999, 2000, and 2004. The goal of this study is twofold: (1) to characterize the long-term X-ray flux and spectral variability of the source with a model-independent analysis, and (2) to investigate the X-ray and TeV correlation on long timescales (> days). Significant spectral variations were observed during all the observations along with long-term timescale correlations between the X-ray colors and the count rate. Specifically, on long timescales, a typical blazar behavior is observed with the spectrum hardening when the source brightens, and the fractional variability correlating with the energy band. A similar spectral trend is observed also in the majority of the individual flares. The spectral and temporal variability properties appear to be markedly different compared to those of non-jet-dominated radio-loud and radio-quiet AGNs monitored with RXTE. To investigate the X-ray-TeV correlation on long timescales we compared RXTE monitoring data with HEGRA and Whipple historical light curves. We confirm the presence of a direct correlation between X-ray and gamma-ray emissions, which appears to be stronger when the source is brighter. The analysis of individual flares shows that the X-ray-TeV correlated activity is heterogeneous, in the sense that it might be both linear and nonlinear, and some X-ray flares seem to be lacking the TeV counterpart. However, more sensitive TeV observations are necessary to confirm these findings, and to put tighter constraints on jet models. C1 George Mason Univ, Fairfax, VA 22030 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. Harvard Smithsonian Ctr Astrophys, CfA, Fred Lawrence Whipple Observ, Amado, AZ 85645 USA. Osserv Astron Brera, Milan, Italy. RP Gliozzi, M (reprint author), George Mason Univ, 4400 Univ Dr, Fairfax, VA 22030 USA. NR 59 TC 30 Z9 30 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 JUL 20 PY 2006 VL 646 IS 1 BP 61 EP 75 DI 10.1086/504700 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072AL UT WOS:000239644900007 ER PT J AU Finoguenov, A Davis, DS Zimer, M Mulchaey, JS AF Finoguenov, Alexis Davis, David S. Zimer, Marc Mulchaey, John S. TI The two-dimensional XMM-Newton Group Survey: z < 0.012 groups SO ASTROPHYSICAL JOURNAL LA English DT Review DE galaxies : clusters : general; intergalactic medium ID EARLY-TYPE GALAXIES; X-RAY-PROPERTIES; ELLIPTIC GALAXIES; DARK-MATTER; ASCA OBSERVATIONS; CHANDRA OBSERVATION; NGC-2300 GROUP; COMPACT-GROUPS; INTERGALACTIC MEDIUM; INTRACLUSTER MEDIUM AB We present the results of the two-dimensional XMM-Newton Group Survey (2dXGS), an archival study of nearby galaxy groups. In this paper we consider 11 nearby systems (z < 0.012) in Mulchaey et al., which span a broad range in X-ray luminosity from 10(40) to 10(43) ergs s(-1). We measure the iron abundance and temperature distribution in these systems and derive pressure and entropy maps. We find statistically significant evidence for structure in the entropy and pressure of the gas component of seven groups on the 10% - 20% level. The XMM-Newton data for the three groups with best statistics also suggest patchy metallicity distributions within the central 20 - 50 kpc of the brightest group galaxy, probed with 2 - 10 kpc resolution. This provides insights into the processes associated with thermalization of the stellar mass loss. Analysis of the global properties of the groups reveals a subclass of X-ray-faint groups, which are characterized by both higher entropy and lower pressure. We suggest that the merger history of the central elliptical is responsible for both the source and the observed thermodynamical properties of the hot gas of the X-ray-faint groups. C1 Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. Univ Maryland Baltimore Cty, Joint Ctr Astrophys, Baltimore, MD 21250 USA. Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Observ Carnegie Inst Washington, Pasadena, CA 91101 USA. RP Finoguenov, A (reprint author), Max Planck Inst Extraterr Phys, Giessenbaachstr, D-85748 Garching, Germany. EM alexis@mpe.mpg.de; ddavis@milkyway.gsfc.nasa.gov; mzimer@mpe.mpg.de; mulchaey@ociw.edu NR 107 TC 30 Z9 30 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 JUL 20 PY 2006 VL 646 IS 1 BP 143 EP 160 DI 10.1086/504697 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072AL UT WOS:000239644900012 ER PT J AU Dale, DA Smith, JDT Armus, L Buckalew, BA Helou, G Kennicutt, RC Moustakas, J Roussel, H Sheth, K Bendo, GJ Calzetti, D Draine, BT Engelbracht, CW Gordon, KD Hollenbach, DJ Jarrett, TH Kewley, LJ Leitherer, C Li, A Malhotra, S Murphy, EJ Walter, F AF Dale, D. A. Smith, J. D. T. Armus, L. Buckalew, B. A. Helou, G. Kennicutt, R. C., Jr. Moustakas, J. Roussel, H. Sheth, K. Bendo, G. J. Calzetti, D. Draine, B. T. Engelbracht, C. W. Gordon, K. D. Hollenbach, D. J. Jarrett, T. H. Kewley, L. J. Leitherer, C. Li, A. Malhotra, S. Murphy, E. J. Walter, F. TI Mid-infrared spectral diagnostics of nuclear and extranuclear regions in nearby galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : nuclei; HII regions; infrared : galaxies; infrared : ISM ID ULTRALUMINOUS INFRARED GALAXIES; ACTIVE GALACTIC NUCLEI; SPITZER-SPACE-TELESCOPE; STAR-FORMING GALAXIES; 3CR RADIO GALAXIES; CLOUD HII-REGIONS; STARBURST GALAXIES; LINE DIAGNOSTICS; ISO-SWS; STELLAR POPULATIONS AB Mid-infrared diagnostics are presented for a large portion of the Spitzer Infrared Nearby Galaxies Survey (SINGS) sample plus archival data from ISO and Spitzer. The SINGS data set includes low- and high-resolution spectral maps and broadband imaging in the infrared for over 160 nuclear and extranuclear regions within 75 nearby galaxies spanning a wide range of morphologies, metallicities, luminosities, and star formation rates. Our main result is that these mid-infrared diagnostics effectively constrain a target's dominant power source. The combination of a high-ionization line index and PAH strength serves as an efficient discriminant between AGNs and star-forming nuclei, confirming progress made with ISO spectroscopy on starbursting and ultraluminous infrared galaxies. The sensitivity of Spitzer allows us to probe fainter nuclear and star-forming regions within galaxy disks. We find that both star-forming nuclei and extranuclear regions stand apart from nuclei that are powered by Seyfert or LINER activity. In fact, we identify areas within four diagnostic diagrams containing > 90% Seyfert/LINER nuclei or > 90% H II regions/ H II nuclei. We also find that, compared to starbursting nuclei, extranuclear regions typically separate even further from AGNs, especially for low-metallicity extranuclear environments. In addition, instead of the traditional mid-infrared approach to differentiating between AGNs and star-forming sources that utilizes relatively weak high-ionization lines, we show that strong low- ionization cooling lines of X-ray-dominated regions like [Si II] 34.82 mu m can alternatively be used as excellent discriminants. Finally, the typical target in this sample shows relatively modest interstellar electron density (similar to 400 cm(-3)) and obscuration (A(V) similar to 1: 0 mag for a foreground screen), consistent with a lack of dense clumps of highly obscured gas and dust residing in the emitting regions. C1 Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. CALTECH, Pasadena, CA 91101 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Max Planck Inst Astron, D-69117 Heidelberg, Germany. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, London SW7 2AZ, England. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. Yale Univ, Dept Astron, New Haven, CT 06520 USA. RP Dale, DA (reprint author), Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. EM ddale@uwyo.edu OI Draine, Bruce/0000-0002-0846-936X NR 72 TC 102 Z9 102 U1 0 U2 5 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 JUL 20 PY 2006 VL 646 IS 1 BP 161 EP 173 DI 10.1086/504835 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072AL UT WOS:000239644900013 ER PT J AU Liang, EW Zhang, B O'Brien, PT Willingale, R Angelini, L Burrows, DN Campana, S Chincarini, G Falcone, A Gehrels, N Goad, MR Grupe, D Kobayashi, S Meszaros, P Nousek, JA Osborne, JP Page, KL Tagliaferri, G AF Liang, E. W. Zhang, B. O'Brien, P. T. Willingale, R. Angelini, L. Burrows, D. N. Campana, S. Chincarini, G. Falcone, A. Gehrels, N. Goad, M. R. Grupe, D. Kobayashi, S. Meszaros, P. Nousek, J. A. Osborne, J. P. Page, K. L. Tagliaferri, G. TI Testing the curvature effect and internal origin of gamma-ray burst prompt emissions and X-ray flares with Swift data SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; methods : statistical ID EXTERNAL SHOCK MODEL; LIGHT CURVES; MILLISECOND PULSARS; AFTERGLOW EMISSION; LONG; VARIABILITY; FIREBALLS; PULSES; ENGINE; GRB-011121 AB The X-ray light curves of many GRBs have a steep tail following the gamma-rays and have some erratic flares. We assume that these tails and flares are of "internal" origin and that their decline behaviors are dominated by the curvature effect. This effect suggests that the decay slope of the late steep decay part of the light curves is alpha = 2 + beta, where beta is the X-ray spectral index. We present a self-consistency test for this scenario with a sample of 36 prompt emission tails/flares in 22 light curves observed by the Swift XRT. We derive the zero time (t(0)) for each steep decay component by fitting the light curves with the constraint of alpha = 2 + beta. Our results show that the t(0) values of the prompt emission tails and the tails of well-separated flares are self-consistent with the expectation of the internal dissipation models, indicating that each X-ray flare forms a distinct episode of the central engine activity and the central engine remains active after the prompt emission is over, sometimes up to similar to 1 day after the GRB trigger. This challenges the conventional models and calls for new ideas to restart the central engine. We further show that the onset time of the late central engine activity does not depend on the GRB duration. We also identify a minority group of GRBs whose combined BAT-XRT light curves are smoothly connected, without an abrupt transition between the prompt emission and the afterglow. These GRBs may have an external origin for both the prompt emission and the afterglow. C1 Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. Guangxi Univ, Dept Phys, Nanning 530004, Peoples R China. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Osserv Astron Brera, INAF, I-23807 Merate, Italy. Univ Milan Bicocca, Dipartimento Fis, I-20126 Milan, Italy. Liverpool John Moores Univ, Astrophys Res Inst, Birkenhead CH41 1LD, Merseyside, England. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. RP Liang, EW (reprint author), Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. EM lew@physics.unlv.edu; bzhang@physics.unlv.edu RI Gehrels, Neil/D-2971-2012; OI Tagliaferri, Gianpiero/0000-0003-0121-0723 NR 59 TC 132 Z9 134 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 JUL 20 PY 2006 VL 646 IS 1 BP 351 EP 357 DI 10.1086/504684 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072AL UT WOS:000239644900029 ER PT J AU Schlegel, EM Petre, R AF Schlegel, Eric M. Petre, Robert TI A Chandra ACIS observation of the X-ray-luminous SN 1988Z SO ASTROPHYSICAL JOURNAL LA English DT Article DE supernovae : individual (SN 1988Z) ID SUPERNOVA-REMNANTS; RADIO-EMISSION; II SUPERNOVAE; SN 1988Z; CATALOG; EJECTA; WIND; MAPS AB SN 1988Z is the most luminous X-ray-emitting supernova, initially detected in 1995 using the ROSAT HRI with a luminosity of similar to 8 x 10(40) ergs s(-1) (Fabian & Terlevich 1996). Its high luminosity was ascribed to expansion of the blast wave into an especially dense circumstellar medium. In this paper, we describe a recent observation of SN 1988Z using the ACIS detector on Chandra. We readily detect SN 1988Z, obtaining similar to 30 net counts, which corresponds to a 0.2-2.0 keV luminosity of similar to 3 x 10(39) ergs s(-1). The calculated quantiles for the extracted counts allow a broad range of temperatures but require a temperature hotter than 5 keV if there is no intrinsic absorption. The long-term light curve (1995-2005) declines as t(-2.6 +/- 0.6). This is one of the steepest X-ray light curves. The X-ray luminosity indicates that the emitting region has a high density (> 10(5) cm(-3)) and that the density profile is not consistent with a constant mass-loss stellar wind during the similar to 5000 yr before the explosion. If the circumstellar medium is due to progenitor mass loss, then the mass-loss rate is extremely high (similar to 10(-3) M-circle dot yr(-1) [v(w)/10 km s(-1)]). The X-ray results are compared with the predictions of models of SN 1988Z. C1 Smithsonian Astrophys Observ, High Energy Astrophys Div, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Xray Astrophys Grp, Greenbelt, MD 20771 USA. RP Schlegel, EM (reprint author), Univ Texas, Dept Phys & Astron, San Antonio, TX 78249 USA. NR 38 TC 17 Z9 17 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 JUL 20 PY 2006 VL 646 IS 1 BP 378 EP 384 DI 10.1086/504890 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072AL UT WOS:000239644900032 ER PT J AU Pietsch, W Haberl, F Sasaki, M Gaetz, TJ Plucinsky, PP Ghavamian, P Long, KS Pannuti, TG AF Pietsch, W. Haberl, F. Sasaki, M. Gaetz, T. J. Plucinsky, P. P. Ghavamian, P. Long, K. S. Pannuti, T. G. TI M33 X-7: ChASeM33 reveals the first eclipsing black hole X-ray binary SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : eclipsing; galaxies : individual (M33); X-rays : binaries; X-rays : individual (M33 X-7) ID ORBITAL DECAY; CENTAURUS X-3; LOCAL GROUP; GALAXY M33; H-I; SCATTERING; LIGHT; CURVES; PERIOD; WINDS AB The first observations conducted as part of the Chandra ACIS survey of M33 (ChASeM33) sampled the eclipsing X-ray binary M33 X-7 over a large part of the 3.45 day orbital period and have resolved eclipse ingress and egress for the first time. The occurrence of the X-ray eclipse allows us to determine an improved ephemeris of mid-eclipse and binary period as HJD (2; 453; 639.119 +/- 0.005) +/- N(3.453014 +/- 0.000020) and constrain the eclipse half-angle to 26 degrees.5 +/- 1 degrees.1. There are indications for a shortening of the orbital period. The X-ray spectrum is best described by a disk blackbody spectrum typical for black hole X-ray binaries in the Galaxy. We find a flat power density spectrum, and no significant regular pulsations were found in the frequency range of 10(-4) to 0.15 Hz. HST WFPC2 images resolve the optical counterpart, which can be identified as an O6 III star with the help of extinction and color corrections derived from the X-ray absorption. Based on the optical light curve, the mass of the compact object in the system most likely exceeds 9 M-circle dot. This mass, the shape of the X-ray spectrum, and the short-term X-ray time variability identify M33 X-7 as the first eclipsing black hole high-mass X-ray binary. C1 Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. CALTECH, Jet Prop Lab, Spitzer Sci Ctr, Pasadena, CA 91125 USA. RP Pietsch, W (reprint author), Max Planck Inst Extraterr Phys, Giessenbachstr, D-85741 Garching, Germany. EM wnp@mpe.mpg.de RI Sasaki, Manami/P-3045-2016 OI Sasaki, Manami/0000-0001-5302-1866 NR 43 TC 31 Z9 31 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 JUL 20 PY 2006 VL 646 IS 1 BP 420 EP 428 DI 10.1086/504704 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072AL UT WOS:000239644900036 ER PT J AU Rajaguru, SP Birch, AC Duvall, TL Thompson, MJ Zhao, J AF Rajaguru, S. P. Birch, A. C. Duvall, T. L., Jr. Thompson, M. J. Zhao, J. TI Sensitivity of time-distance helioseismic measurements to spatial variation of oscillation amplitudes. I. Observations and a numerical model SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : helioseismology; Sun : magnetic fields; Sun : oscillations; sunspots ID SOLAR ACTIVE-REGION; SURFACE AMPLITUDES; MAGNETIC-FIELDS; SUNSPOT; MDI; TOMOGRAPHY; INVERSION; BENEATH; GONG AB It is well known that the observed amplitude of solar oscillations is lower in sunspots than in quiet regions of the Sun. We show that this local reduction in oscillation amplitudes, combined with the phase-speed filtering procedure in time-distance helioseismic analyses, could be a source of systematic errors in the range of 5%-40% in the measured travel-time anomalies of acoustic waves around sunspots. Removing these travel-time artifacts is important for correctly inferring the subsurface structure of sunspots. We suggest an empirical correction procedure and illustrate its usage for a small sunspot. This work uses data from SOHO MDI. C1 Stanford Univ, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA. NW Res Assoc Inc, Colorado Res Assoc, Boulder, CO 80301 USA. NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Greenbelt, MD 20771 USA. Univ Sheffield, Dept Appl Math, Sheffield S3 7RH, S Yorkshire, England. RP Rajaguru, SP (reprint author), Stanford Univ, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA. EM rajaguru@sun.stanford.edu RI Zhao, Junwei/A-1177-2007; Duvall, Thomas/C-9998-2012 NR 37 TC 31 Z9 31 U1 0 U2 5 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 JUL 20 PY 2006 VL 646 IS 1 BP 543 EP 552 DI 10.1086/504705 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072AL UT WOS:000239644900046 ER PT J AU Duvall, TL Birch, AC Gizon, L AF Duvall, T. L., Jr. Birch, A. C. Gizon, L. TI Direct measurement of travel-time kernels for helioseismology SO ASTROPHYSICAL JOURNAL LA English DT Article DE methods : data analysis; scattering; Sun : helioseismology; Sun : magnetic fields; techniques : image processing ID DISTANCE HELIOSEISMOLOGY; SENSITIVITY; ABSORPTION; INTERIOR; SUNSPOTS; MODE AB Solar f-modes are surface gravity waves that propagate horizontally in a thin layer near the photosphere with a dispersion relation approximately that of deep water waves. At the power maximum near frequency omega/2 pi = 3 mHz, the wavelength of 5Mm is large enough for various wave scattering properties to be observable. Gizon & Birch have calculated spatial kernels for scattering in the Born approximation. In this paper, using isolated small magnetic features as approximate point scatterers, a linear-response kernel has been measured. In addition, the kernel has been estimated by deconvolving the magnetograms from the travel-time maps. The observed kernel is similar to the theoretical kernel for wave damping computed by Gizon & Birch: it includes elliptical and hyperbolic features. This is the first observational evidence to suggest that it is appropriate to use the Born approximation to compute kernels (as opposed to the ray approximation). Furthermore, the observed hyperbolic features confirm that it is important to take into account scattering of the waves coming from distant source locations (as opposed to the single-source approximation). The observed kernel is due to a superposition of the direct and indirect effects of the magnetic field. A simple model that includes both monopole and dipole scattering compares favorably with the data. This new technique appears to be promising to study how seismic waves interact with magnetic flux tubes. C1 NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Greenbelt, MD 20771 USA. Colorado Res Assoc Div, NW Res Assoc, Boulder, CO 80301 USA. Max Planck Inst Sonnensystemforsch, D-37191 Katlenburg Lindau, Germany. RP Duvall, TL (reprint author), NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Code 661, Greenbelt, MD 20771 USA. EM thomas.l.duvall@nasa.gov; aaronb@cora.nwra.com; gizon@mps.mpg.de RI Gizon, Laurent/B-9457-2008; Duvall, Thomas/C-9998-2012 NR 19 TC 30 Z9 30 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 JUL 20 PY 2006 VL 646 IS 1 BP 553 EP 559 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072AL UT WOS:000239644900047 ER PT J AU Sui, LH Holman, GD Dennis, BR AF Sui, Linhui Holman, Gordon D. Dennis, Brian R. TI Enigma of a flare involving multiple-loop interactions: Emerging, colliding loops or magnetic breakout? SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : flares; Sun : X-rays, gamma rays ID CORONAL MASS EJECTION; X-RAY TELESCOPE; ENERGY-RELEASE SITE; 2002 JULY 15; SOLAR-FLARE; OBSERVATIONAL EVIDENCE; RECONNECTION; MODEL; RHESSI; ERUPTION AB We present observations of a C9.4 flare on 2002 June 2 in EUV (TRACE), X-rays (RHESSI), and H alpha (Meudon and Ondrejov) showing evidence for multiple-loop interactions as the cause of the flare. The multiwavelength data reveal some striking phenomena that can be used to test different models for solar eruptive events: (1) involvement of a quadrupolar magnetic configuration; (2) loop expansion and ribbon motion in the preimpulsive phase; (3) gradual formation of a new compact loop with a long cusp at the top during the impulsive phase of the flare; (4) appearance of a large, twisted loop above the cusp expanding outward immediately after the hard X-ray peak; (5) eruption of an S-shaped preflare filament trailing closely behind the twisted loop; and (6) X-ray emission observed only from the new compact loop and the cusp. The emerging flux model and the magnetic breakout model are both applied to interpret the observations. We find that both models are able to explain the general change of the loop morphology for the flare. The magnetic breakout model best addresses the preimpulsive features. Most > 25 keV hard X-rays were emitted during the formation process of the EUV cusp, suggesting that fast reconnection occurred during the restructuring of the magnetic configuration, resulting in more efficient particle acceleration, while the reconnection slowed after the cusp was completely formed and the magnetic geometry was stabilized. C1 Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Greenbelt, MD 20771 USA. RP Sui, LH (reprint author), Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. RI Holman, Gordon/C-9548-2012; Dennis, Brian/C-9511-2012 NR 49 TC 13 Z9 13 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 JUL 20 PY 2006 VL 646 IS 1 BP 605 EP 614 DI 10.1086/504885 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072AL UT WOS:000239644900051 ER PT J AU Korycansky, DG Harrington, J Deming, D Kulick, ME AF Korycansky, D. G. Harrington, Joseph Deming, Drake Kulick, Matthew E. TI Shoemaker-Levy 9 impact modeling. I. High-resolution three-dimensional bolides SO ASTROPHYSICAL JOURNAL LA English DT Article DE comets : individual (Shoemaker-Levy 9); hydrodynamics ID COMET SHOEMAKER-LEVY-9; VENUSIAN ATMOSPHERE; JOVIAN ATMOSPHERE; TIDAL BREAKUP; 3D MODELS; JUPITER; SIZE; DENSITY; PLUME; SIMULATIONS AB We have run high-resolution, three-dimensional, hydrodynamic simulations of the impact of comet Shoemaker-Levy 9 into the atmosphere of Jupiter. We find that the energy deposition profile is largely similar to the previous two-dimensional calculations of Mac Low & Zahnle, although perhaps somewhat broader in the range of height over which the energy is deposited. As with similar calculations for impacts into the Venusian atmosphere, there is considerable sensitivity in the results to small changes in the initial conditions, indicating dynamical chaos. We calculated the median depth of energy deposition (the height z at which 50% of the bolide's energy has been released) per run. The mean value among runs is approximate to 70 km below the 1 bar level, for a 1 km diameter impactor of porous ice of density p = 0.6 g cm(-3). The standard deviation among these runs is 14 km. We find little evidence of a trend in these results with the resolution of the calculations (up to 57 cells across the impactor radius, or 8.8 m resolution), suggesting that resolutions as low as 16 grid cells across the radius of the bolide may yield good results for this particular quantity. Visualization of the bolide breakup shows that the ice impactors were shredded and/or compressed in a complicated manner but evidently did not fragment into separate, coherent masses, unlike calculations for basalt impactors. The processes that destroy the impactor take place at significantly shallower levels in the atmosphere (similar to-40 km for a 1 km diameter bolide), but the shredded remains have enough inertia to carry them down another scale height or more before they lose their kinetic energy. Comparison of basalt impactor models shows that energy deposition curves for these objects have much less sensitivity to initial conditions than do ice impactors, which may reflect differences in the equation of state for the different kinds of objects, or a scale-dependent breakup phenomenology, with the preferred scale depending on impactor density. Models of impactors covering a similar to 600-fold range of mass (m) show that larger impactors descend slightly deeper than expected from scaling the intercepted atmospheric column mass by the impactor mass. Instead, the intercepted column mass scales as m(1.2). C1 Univ Calif Santa Cruz, Dept Earth Sci, CODEP, Santa Cruz, CA 95064 USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Greenbelt, MD 20771 USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. RP Korycansky, DG (reprint author), Univ Calif Santa Cruz, Dept Earth Sci, CODEP, Santa Cruz, CA 95064 USA. EM kory@pmc.ucsc.edu; jh@oobleck.astro.cornell.edu; ddeming@pop600.gsfc.nasa.gov; mek28@cornell.edu RI Harrington, Joseph/E-6250-2011; OI Harrington, Joseph/0000-0002-8955-8531 NR 52 TC 9 Z9 9 U1 1 U2 6 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 JUL 20 PY 2006 VL 646 IS 1 BP 642 EP 652 DI 10.1086/504702 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072AL UT WOS:000239644900055 ER PT J AU Chen, H Gu, MF Beiersdorfer, P Boyce, KR Brown, GV Kahn, SM Kelley, RL Kilbourne, CA Porter, FS Scofield, JH AF Chen, H. Gu, M. F. Beiersdorfer, P. Boyce, K. R. Brown, G. V. Kahn, S. M. Kelley, R. L. Kilbourne, C. A. Porter, F. S. Scofield, J. H. TI Electron impact excitation cross section measurement for n=3 to n=2 line emission in Fe17+ to Fe23+ SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; atomic processes; X-rays : general ID X-RAY SPECTROMETER; BEAM ION-TRAP; L-SHELL IONS; LABORATORY MEASUREMENTS; FE-XVII; RELATIVE INTENSITY; XMM-NEWTON; TRANSITIONS; IRON; XXIV AB We report the measurement of electron impact excitation cross sections for the strong iron L-shell 3 ! 2 lines of Fe XVIII through Fe XXIV at the EBIT-I electron beam ion trap using a crystal spectrometer and a 6 x 6 pixel array microcalorimeter. The cross sections were determined by direct normalization to the well established theoretical cross section of radiative electron capture through a sophisticated model analysis, which results in the excitation cross section for 48 lines at multiple electron energies. We also studied the electron-density-dependent nature of the emission lines, which is demonstrated by the effective excitation cross section of the 3d -> 2p transition in Fe XXI. C1 Lawrence Livermore Natl Lab, High Temp & Astrophys Div, Livermore, CA 94551 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Chen, H (reprint author), Lawrence Livermore Natl Lab, High Temp & Astrophys Div, Livermore, CA 94551 USA. RI Porter, Frederick/D-3501-2012; Kelley, Richard/K-4474-2012 OI Porter, Frederick/0000-0002-6374-1119; NR 34 TC 17 Z9 17 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 JUL 20 PY 2006 VL 646 IS 1 BP 653 EP 665 DI 10.1086/504708 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072AL UT WOS:000239644900056 ER PT J AU Bolton, AS Moustakas, LA Stern, D Burles, S Dey, A Spinrad, H AF Bolton, Adam S. Moustakas, Leonidas A. Stern, Daniel Burles, Scott Dey, Arjun Spinrad, Hyron TI A new Einstein cross: A highly magnified, intrinsically faint Ly alpha emitter at z=2.7 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gravitational lensing; galaxies : elliptical and lenticular, cD; galaxies : high-redshift; galaxies : individual (SDSS J101129.49+014323.3); galaxies : starburst; techniques : spectroscopic ID DIGITAL SKY SURVEY; GRAVITATIONALLY LENSED QUASAR; NONPARAMETRIC RECONSTRUCTION; SNAPSHOT SURVEY; HIGH-REDSHIFT; DARK-MATTER; ACS SURVEY; GALAXY; DISCOVERY; SAMPLE AB We report the discovery of a new Einstein cross at redshift z(source) = 2.701 based on Ly alpha emission in a cruciform configuration around an SDSS luminous red galaxy (z(lens) = 0.331). The system was targeted as a possible lens based on an anomalous emission line in the SDSS spectrum. Imaging and spectroscopy from the W. M. Keck Observatory confirm the lensing nature of this system. This is one of the widest-separation galaxy-scale lenses known, with an Einstein radius theta(E) similar or equal to 1.'' 84. We present simple gravitational lens models for the system and compute the intrinsic properties of the lensed galaxy. The total mass of the lensing galaxy within the 8.8 +/- 0.1 kpc enclosed by the lensed images is (5.2 +/- 0.1)x 10(11) M circle dot. The lensed galaxy is a low-mass galaxy (0.2L*) with a high equivalent width Lya line (EWLy alpha rest = 46 +/- 5 angstrom). Follow-up studies of this lens system can probe the mass structure rest of the lensing galaxy and can provide a unique view of an intrinsically faint, high-redshift, star-forming galaxy at high signal-to-noise ratio. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 USA. Natl Opt Astron Observ, Tucson, AZ 85719 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RP Bolton, AS (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM abolton@cfa.harvard.edu NR 35 TC 10 Z9 10 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 JUL 20 PY 2006 VL 646 IS 1 BP L45 EP L48 DI 10.1086/506446 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072BI UT WOS:000239647200012 ER PT J AU Brookes, MH Lawrence, CR Keene, J Stern, D Gorijan, V Werner, M Charmandaris, V AF Brookes, M. H. Lawrence, C. R. Keene, J. Stern, D. Gorijan, V. Werner, M. Charmandaris, V. TI Spitzer observations of Centaurus A: Infrared synchrotron emission from the northern lobe SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (Centaurus A); radiation mechanisms : nonthermal; radio continuum : galaxies ID X-RAY-EMISSION; SPACE-TELESCOPE; RADIO; JET; MISSION AB We present measurements obtained with the Spitzer Space Telescope in five bands from 3.6 to 24 mm of the northern inner radio lobe of Centaurus A, the nearest powerful radio galaxy. We show that this emission is synchrotron in origin. Comparison with ultraviolet observations from GALEX shows that diffuse ultraviolet emission exists in a smaller region than the infrared but also coincides with the radio jet. We discuss the possibility that synchrotron emission is responsible for the ultraviolet emission, and we conclude that further data are required to confirm this. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Crete, Dept Phys, GR-71003 Iraklion, Greece. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. RP Brookes, MH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Mairi.H.Brookes@jpl.nasa.gov RI Charmandaris, Vassilis/A-7196-2008 OI Charmandaris, Vassilis/0000-0002-2688-1956 NR 23 TC 8 Z9 8 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 JUL 20 PY 2006 VL 646 IS 1 BP L41 EP L44 DI 10.1086/506472 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072BI UT WOS:000239647200011 ER PT J AU Howell, SB Brinkworth, C Hoard, DW Wachter, S Harrison, T Chun, H Thomas, B Stefaniak, L Ciardi, DR Szkody, P van Belle, G AF Howell, Steve B. Brinkworth, Carolyn Hoard, D. W. Wachter, Stefanie Harrison, Thomas Chun, Howard Thomas, Beth Stefaniak, Linda Ciardi, David R. Szkody, Paula van Belle, Gerard TI First Spitzer Space Telescope observations of magnetic cataclysmic variables: Evidence of excess emission at 3-8 mu m SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : individual (EF Eridani, GG Leonis, V347 Pavonis, RX J0154.0-5947); stars : low-mass, brown dwarfs ID INFRARED-SPECTROSCOPY; CIRCUMBINARY DISKS; WHITE-DWARFS; STAR AB We present the first observations of magnetic cataclysmic variables using the Spitzer Space Telescope. We used the Infrared Array Camera to obtain photometry of the Polars EF Eri, GG Leo, V347 Pav, and RX J0154.0-5947 at 3.6, 4.5, 5.8, and 8.0 mu m, respectively. In all of our targets, we detect excess mid-infrared emission over that expected from the component stars alone. We explore the origin of this IR excess by examining bremsstrahlung, cyclotron emission, circumbinary dust, and L/T brown dwarf secondary stars. Bremsstrahlung and cyclotron emission appear unlikely to be significant contributors to the observed fluxes. At present, the most likely candidate for the excess emission is dust that is probably located in a circumbinary disk with an inner temperature near 800 K. However, a simple dust disk plus any reasonable low-mass or brown dwarf-like secondary star is unable to fully explain the observed flux densities in the 3-8 mu m region. C1 WIYN Observ, Tucson, AZ 85719 USA. Natl Opt Astron Observ, Tucson, AZ 85719 USA. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA. NASA, NOAO, Spitzer Space Telescope Observing Program Student, Washington, DC 20546 USA. Cranston High Sch E, Cranston, RI 02910 USA. Great Falls Publ Sch, Great Falls, MT 59404 USA. Allentown High Sch, Allentown, NJ 08501 USA. CALTECH, Michelson Sci Ctr, Pasadena, CA 91125 USA. Univ Washington, Dept Astron, Seattle, WA 98195 USA. RP Howell, SB (reprint author), WIYN Observ, 950 N Cherry Ave, Tucson, AZ 85719 USA. EM howell@noao.edu OI Hoard, Donald W./0000-0002-6800-6519 NR 19 TC 20 Z9 20 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 JUL 20 PY 2006 VL 646 IS 1 BP L65 EP L68 DI 10.1086/506558 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072BI UT WOS:000239647200017 ER PT J AU Marsh, KA Dowell, CD Velusamy, T Grogan, K Beichman, CA AF Marsh, K. A. Dowell, C. D. Velusamy, T. Grogan, K. Beichman, C. A. TI Images of the Vega dust ring at 350 and 450 mu m: New clues to the trapping of multiple-sized dust particles in planetary resonances SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; planetary systems; stars : individual (Vega) ID DEBRIS DISK; STARS AB We have used the SHARC II camera at Caltech Submillimeter Observatory to make 350 and 450 mu m images of the Vega dust disk at spatial resolutions (FWHM) of 9.'' 7 and 11.'' 1, respectively. The images show a ringlike morphology (radius similar to 100 AU) with inhomogeneous structure that is qualitatively different from that previously reported at 850 mu m and longer wavelengths. We attribute the 350/450 mu m emission to a grain population whose characteristic size (similar to 1 mm) is intermediate between that of the centimeter-sized grains responsible for emission longward of 850 mu m and the much smaller grains (less than or similar to 18 mu m) in the extensive halo, visible at 70 mu m, discussed by Su et al. We have combined our submillimeter images with Spitzer data at 70 mu m to produce two-dimensional maps of line-of-sight optical depth (relative column density). These "tau maps" suggest that the millimeter-sized grains are located preferentially in three symmetrically located concentrations. If so, then this structure could be understood in terms of the Wyatt model in which planetesimals are trapped in the mean motion resonances of a Neptune-mass planet at 65 AU, provided allowance is made for the spatial distribution of dust grains to differ from that of the parent planetesimals. The peaks of the tau maps are, in fact, located near the expected positions corresponding to the 4 : 3 resonance. If this identification is confirmed by future observations, it would resolve an ambiguity with regard to the location of the planet. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, IPAC, Pasadena, CA 91125 USA. RP Marsh, KA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM kenneth.a.marsh@jpl.nasa.gov; cdd@submm.caltech.edu; thangasamy.velusamy@jpl.nasa.gov; keith.grogan@jpl.nasa.gov; chas@ipac.caltech.edu NR 13 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 JUL 20 PY 2006 VL 646 IS 1 BP L77 EP L80 DI 10.1086/506520 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072BI UT WOS:000239647200020 ER PT J AU Stanford, SA Romer, AK Sabirli, K Davidson, M Hilton, M Viana, PTP Collins, CA Kay, ST Liddle, AR Mann, RG Miller, CJ Nichol, RC West, MJ Conselice, CJ Spinrad, H Stern, D Bundy, K AF Stanford, S. A. Romer, A. Kathy Sabirli, Kivanc Davidson, Michael Hilton, Matt Viana, Pedro T. P. Collins, Chris A. Kay, Scott T. Liddle, Andrew R. Mann, Robert G. Miller, Christopher J. Nichol, Robert C. West, Michael J. Conselice, Christopher J. Spinrad, Hyron Stern, Daniel Bundy, Kevin TI The XMM cluster survey: A massive galaxy cluster at z=1.45 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : evolution; galaxies : formation ID CHANDRA; SAMPLE AB We report the discovery of XMMXCS J2215.9-1738, a massive galaxy cluster at, which was found z = 1.45 in the XMM Cluster Survey. The cluster candidate was initially identified as an extended X-ray source in archival XMM data. Optical spectroscopy shows that six galaxies within a similar to 60 '' diameter region lie at. z p 1.45 +/- 0.01 Model fits to the X-ray spectra of the extended emission yield kT = 7.4(-1.8)(+2.7) keV (90% confidence); if there is an undetected central X-ray point source, then kT = 6.5(-1.8)(+2.6). The bolometric X-ray luminosity is L-x-0.6(+0.8) x 10(44) ergs s(-1) over a 2 Mpc radial region. The measured T-x, which is the highest for any known cluster at z > 1, suggests that this cluster is relatively massive for such a high redshift. The redshift of XMMXCS of J2215.9-1738 is the highest currently known for a spectroscopically confirmed cluster of galaxies. C1 Univ Calif Davis, Davis, CA 95616 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94551 USA. Univ Sussex, Ctr Astron, Brighton BN1 9QJ, E Sussex, England. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15217 USA. Univ Edinburgh, Astron Inst, Edinburgh EH9 9HJ, Midlothian, Scotland. Liverpool John Moores Univ, Astrophys Res Inst, Birkenhead CH41 1LD, Merseyside, England. Univ Porto, Fac Ciencias, Dept Matemat Aplicada, P-4169007 Oporto, Portugal. Univ Porto, Ctr Astrofis, P-4150762 Oporto, Portugal. Natl Opt Astron Observ, Cerro Tololo Interamer Observ, Tucson, AZ 85719 USA. Univ Portsmouth, Inst Cosmol & Gravitat, Portsmouth PO1 2EG, Hants, England. Univ Hawaii, Dept Phys & Astron, Hilo, HI 96720 USA. Gemini Observ, La Serena, Chile. Univ Nottingham, Nottingham NG9 2RD, England. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Pasadena, CA 91125 USA. RP Stanford, SA (reprint author), Univ Calif Davis, Davis, CA 95616 USA. EM adam@igpp.ucllnl.org RI Conselice, Christopher/B-4348-2013; Hilton, Matthew James/N-5860-2013; OI Conselice, Christopher/0000-0003-1949-7638 NR 23 TC 109 Z9 109 U1 0 U2 5 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 JUL 20 PY 2006 VL 646 IS 1 BP L13 EP L16 DI 10.1086/506449 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 072BI UT WOS:000239647200004 ER PT J AU Folkner, WM Asmar, SW Border, JS Franklin, GW Finley, SG Gorelik, J Johnston, DV Kerzhanovich, VV Lowe, ST Preston, RA Bird, MK Dutta-Roy, R Allison, M Atkinson, DH Edenhofer, P Plettemeier, D Tyler, GL AF Folkner, W. M. Asmar, S. W. Border, J. S. Franklin, G. W. Finley, S. G. Gorelik, J. Johnston, D. V. Kerzhanovich, V. V. Lowe, S. T. Preston, R. A. Bird, M. K. Dutta-Roy, R. Allison, M. Atkinson, D. H. Edenhofer, P. Plettemeier, D. Tyler, G. L. TI Winds on Titan from ground-based tracking of the Huygens probe SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID GALILEO PROBE; ATMOSPHERE; JUPITER; DESCENT; SURFACE; WAVE AB [1] Large radio telescopes on Earth tracked the radio signal transmitted by the Huygens probe during its mission at Titan. Frequency measurements were conducted as a part of the Huygens Doppler Wind Experiment (DWE) in order to derive the velocity of the probe in the direction to Earth. The DWE instrumentation on board Huygens consisted of an ultrastable oscillator which maintained the high Doppler stability required for a determination of probe horizontal motion during the atmospheric descent. A vertical profile of the zonal wind velocity in Titan's atmosphere was constructed from the Doppler data under the plausible assumption of generally small meridional wind, as validated by tracked images from the Huygens Descent Imager/Spectral Radiometer (DISR). We report here on improved results based on data with higher temporal resolution than that presented in the preliminary analysis by Bird et al. (2005), corroborating the first in situ measurement of Titan's atmospheric superrotation and a region of strong vertical shear reversal within the lower stratosphere. We also present the first high-resolution display and interpretation of the winds near the surface and planetary boundary layer. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91001 USA. Univ Bonn, Argelander Inst Astron, D-53125 Bonn, Germany. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Idaho, Dept Elect & Comp Engn, Moscow, ID 83844 USA. Univ Bochum, Inst HF Tech, D-44780 Bochum, Germany. Tech Univ Dresden, Elektrotech Inst, D-01062 Dresden, Germany. Stanford Univ, Ctr Radar Astron, Stanford, CA 94305 USA. RP Folkner, WM (reprint author), CALTECH, Jet Propuls Lab, 4800 Oak Grove Dr,Mail Stop 301-460, Pasadena, CA 91001 USA. EM william.folkner@jpl.nasa.gov NR 25 TC 29 Z9 29 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 JUL 20 PY 2006 VL 111 IS E7 AR E07S02 DI 10.1029/2005JE002649 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 071EM UT WOS:000239581100001 ER PT J AU Gudipati, MS Allamandola, LJ AF Gudipati, Murthy S. Allamandola, Louis J. TI Double ionization of quaterrylene (C40H20) in water-ice at 20 K with Ly(alpha) (121.6 nm) radiation SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID POLYCYCLIC AROMATIC-HYDROCARBONS; DENSITY-FUNCTIONAL THEORY; OUTER SOLAR-SYSTEM; ASTROPHYSICAL ICES; FACILE GENERATION; MATRIX-ISOLATION; RADICAL CATIONS; AMINO-ACIDS; GAS-PHASE; ANALOGS AB Polycyclic aromatic hydrocarbon (PAH) molecules undergo facile ionization in cryogenic water-ices resulting in near quantitative conversions of neutral molecules to the corresponding singly charged radical cations. Here we report, for the first time, the production and stabilization of a doubly ionized, closed shell PAH in water-ice. The large PAH quaterrylene (QTR, C40H2O) is readily photoionized and stabilized as QTR(2+) in a water- ice matrix at 20 K. The kinetic analysis of photolysis shows that the QTR2+ is formed at the expense of QTR(+), not directly from QTR. The long-axis polarized S-1-S-0 (1(1)B(3u) -> 1(1)Ag) transition for QTR2+ falls at 1.59 eV (782 nm). TD-DFT calculations at the B3LYP level predict that this transition falls at 1.85 eV (670 nm) for free gas-phase QTR(2+), within the 0.3 eV uncertainty associated with these calculations. This red shift of 0.26 eV is quite similar to the 0.24 eV red shift between the TD-DFT computational prediction for the lowest energy transition for QTR+ (1.68 eV) and its value in a water matrix (1.44 eV). These results suggest that multiple photoionization of such large PAHs in water-ice can be an efficient process in general. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. RP Gudipati, MS (reprint author), NASA, Ames Res Ctr, Mail Stop 245-6, Moffett Field, CA 94035 USA. EM gudipati@glue.umd.edu; louis.j.allamandola@nasa.gov RI Gudipati, Murthy/F-7575-2011 NR 36 TC 8 Z9 8 U1 2 U2 7 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 JUL 20 PY 2006 VL 110 IS 28 BP 9020 EP 9024 DI 10.1021/jp061416n PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 063EX UT WOS:000239001600049 PM 16836467 ER PT J AU Sokoloski, JL Luna, GJM Mukai, K Kenyon, SJ AF Sokoloski, J. L. Luna, G. J. M. Mukai, K. Kenyon, Scott J. TI An X-ray-emitting blast wave from the recurrent nova RS Ophiuchi SO NATURE LA English DT Article ID PROGENITOR SYSTEM; MODELS; EMISSION; OUTBURST; REMNANTS; ORBIT AB Stellar explosions such as novae and supernovae produce most of the heavy elements in the Universe. The onset of a nova is well understood(1) as driven by runaway thermonuclear fusion reactions on the surface of a white dwarf in a binary star system; but the structure, dynamics and mass of the ejecta are not well known. In rare cases, the white dwarf is embedded in the wind nebula of a red-giant companion, and the explosion products plough through the nebula and produce X-ray emission. Here we report X-ray observations of such an event, from the eruption of the recurrent nova RS Ophiuchi(2,3). The hard X-ray emission from RS Ophiuchi early in the eruption emanates from behind a blast wave, or outward-moving shock wave, that expanded freely for less than 2 days and then decelerated owing to interaction with the nebula. The X-rays faded rapidly, suggesting that the blast wave deviates from the standard spherical shell structure(4-6). The early onset of deceleration indicates that the ejected shell had a low mass, the white dwarf has a high mass(7), and that RS Ophiuchi is therefore a progenitor of the type of supernova ( type Ia) integral to studies of the expansion of the Universe. C1 Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508900 Sao Paulo, Brazil. Univ Space Res Assoc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sokoloski, JL (reprint author), Smithsonian Astrophys Observ, 60 Garden St, Cambridge, MA 02138 USA. EM jsokoloski@cfa.harvard.edu OI Kenyon, Scott/0000-0003-0214-609X NR 30 TC 126 Z9 127 U1 12 U2 13 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 20 PY 2006 VL 442 IS 7100 BP 276 EP 278 DI 10.1038/nature04893 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 064WT UT WOS:000239122100032 PM 16855584 ER PT J AU Fennel, K Wilkin, J Levin, J Moisan, J O'Reilly, J Haidvogel, D AF Fennel, Katja Wilkin, John Levin, Julia Moisan, John O'Reilly, John Haidvogel, Dale TI Nitrogen cycling in the Middle Atlantic Bight: Results from a three-dimensional model and implications for the North Atlantic nitrogen budget SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID CONTINENTAL-SHELF SEDIMENTS; SPRING PHYTOPLANKTON BLOOM; GEORGES-BANK; SENSITIVITY ANALYSIS; MARINE-SEDIMENTS; ECOSYSTEM MODEL; DYNAMIC-MODEL; COASTAL AREAS; MIXED-LAYER; OCEAN AB [1] The biogeochemistry of continental shelf systems plays an important role in the global elemental cycling of nitrogen and carbon, but remains poorly quantified. We have developed a high-resolution physical-biological model for the U. S. east coast continental shelf and adjacent deep ocean that is nested within a basin-wide North Atlantic circulation model in order to estimate nitrogen fluxes in the shelf area of the Middle Atlantic Bight (MAB). Our biological model is a relatively simple representation of nitrogen cycling processes in the water column and organic matter remineralization at the water-sediment interface that explicitly accounts for sediment denitrification. Climatological and regionally integrated means of nitrate, ammonium, and surface chlorophyll are compared with its model equivalents and were found to agree within 1 standard deviation. We also present regional means of primary production and denitrification, and statistical measures of chlorophyll pattern variability. A nitrogen budget for the MAB shows that the sediment denitrification flux is quantitatively important in determining the availability of fixed nitrogen and shelf primary production ( it was found to remove 90% of all the nitrogen entering the MAB). Extrapolation of nitrogen fluxes estimated for the MAB to the North Atlantic basin suggests that shelf denitrification removes 2.3 x 10(12) mol N annually; this estimate exceeds estimates of N-2 fixation by up to an order of magnitude. Our results emphasize the importance of representing shelf processes in biogeochemical models. C1 Rutgers State Univ, Inst Marine & Coastal Sci, New Brunswick, NJ 08901 USA. Rutgers State Univ, Dept Geol Sci, New Brunswick, NJ 08903 USA. NASA, Goddard Space Flight Ctr, Observat Sci Branch, Lab Hydrospher Proc,Wallops Flight Facil, Wallops Isl, VA 23337 USA. NOAA, Natl Marine Fisheries Serv, Narragansett Lab, Narragansett, RI 02882 USA. RP Fennel, K (reprint author), Rutgers State Univ, Inst Marine & Coastal Sci, 71 Dudley Rd, New Brunswick, NJ 08901 USA. EM kfennel@marine.rutgers.edu; wilkin@marine.rutgers.edu; julia@marine.rutgers.edu; jmoisan@osb.wff.nasa.gov; jay.o'reilly@noaa.gov; dale@marine.rutgers.edu RI Fennel, Katja/A-7470-2009; Wilkin, John/E-5343-2011; Moisan, John/B-8762-2016 OI Fennel, Katja/0000-0003-3170-2331; Wilkin, John/0000-0002-5444-9466; Moisan, John/0000-0002-8078-8939 NR 84 TC 139 Z9 145 U1 8 U2 42 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD JUL 19 PY 2006 VL 20 IS 3 AR GB3007 DI 10.1029/2005GB002456 PG 14 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 071DM UT WOS:000239578200001 ER PT J AU Ignatov, A Minnis, P Miller, WF Wielicki, BA Remer, L AF Ignatov, Alexander Minnis, Patrick Miller, Walter F. Wielicki, Bruce A. Remer, Lorraine TI Consistency of global MODIS aerosol optical depths over ocean on Terra and Aqua CERES SSF data sets SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID INDIVIDUAL AVHRR CHANNELS; INFORMATION-CONTENT; SATELLITES; RETRIEVALS; VALIDATION; ALGORITHM; PRODUCTS; CLOUDS; NOAA AB [1] Aerosol retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra and Aqua platforms are available from the Clouds and the Earth's Radiant Energy System (CERES) Single Scanner Footprint (SSF) data sets. Over ocean, two aerosol products are reported side by side. The primary M product is generated by subsetting and remapping the multispectral (from 0.47 to 2.1 mu m) MOD04/MYD04 oceanic aerosol data onto CERES footprints. M*D04 processing uses cloud screening and aerosol algorithms developed by the MODIS science team. The secondary AVHRR-like A product is generated in only two MODIS bands. The A processing uses the CERES cloud-screening algorithm and NOAA/NESDIS glint identification and single-channel aerosol retrieval algorithms. The M and A products have been documented elsewhere and preliminarily compared using 2 weeks of global Terra CERES SSF edition 1A data, in which the M product was based on MOD04 collection 3. In this study, the comparisons between the M and A aerosol optical depths (AOD) in MODIS band 1 (0.64 mu m), tau(1M) and tau(1A), are reexamined using 9 days of global CERES SSF Terra edition 2A and Aqua edition 1B data from 13 to 21 October 2002 and extended to include cross-platform comparisons. The M and A products on the new CERES SSF release are generated using the same aerosol algorithms as before but with different preprocessing and sampling procedures, thus lending themselves to a simple sensitivity check to nonaerosol factors. Both tau(1M) and tau(1A) generally compare well across platforms. However, the M product shows larger differences, which increase with ambient cloud amount and toward the solar side of the orbit. The cross-platform, cross-product, and cross-release comparisons conducted in this study confirm an earlier observation that the major area for improvement in the current aerosol processing lies in a more formalized and standardized sampling (most importantly, cloud screening), whereas optimization of the aerosol algorithm is deemed to be an important yet less critical element. C1 NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Camp Springs, MD 20746 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Sci Applicat Int Corp, Hampton, VA USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ignatov, A (reprint author), NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, E-RA3,Room 603,WWB,5200 Auth Rd, Camp Springs, MD 20746 USA. EM alex.ignatov@noaa.gov RI Ignatov, Alexander/F-5594-2010; Minnis, Patrick/G-1902-2010 OI Ignatov, Alexander/0000-0002-7463-5944; Minnis, Patrick/0000-0002-4733-6148 NR 25 TC 8 Z9 8 U1 0 U2 1 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 JUL 19 PY 2006 VL 111 IS D14 AR D14202 DI 10.1029/2005JD006645 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 071DQ UT WOS:000239578700004 ER PT J AU Sioris, CE Kovalenko, LJ McLinden, CA Salawitch, RJ Van Roozendael, M Goutail, F Dorf, M Pfeilsticker, K Chance, K von Savigny, C Liu, X Kurosu, TP Pommereau, JP Bosch, H Frerick, J AF Sioris, C. E. Kovalenko, L. J. McLinden, C. A. Salawitch, R. J. Van Roozendael, M. Goutail, F. Dorf, M. Pfeilsticker, K. Chance, K. von Savigny, C. Liu, X. Kurosu, T. P. Pommereau, J. -P. Boesch, H. Frerick, J. TI Latitudinal and vertical distribution of bromine monoxide in the lower stratosphere from Scanning Imaging Absorption Spectrometer for Atmospheric Chartography limb scattering measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RADIATIVE-TRANSFER; INORGANIC BROMINE; TROPOSPHERIC BRO; ODIN SATELLITE; OZONE; SCIAMACHY; CHEMISTRY; SPECTRA; RETRIEVAL; PROFILES AB [1] Vertical profiles of stratospheric bromine monoxide (BrO) in the 15-30 km range are retrieved from SCIAMACHY limb scatter data over the globe. First validation comparisons with the balloon-borne SAOZ-BrO and LPMA/DOAS instruments indicate retrieval biases of similar to 20% or less. Propagated spectral fitting uncertainties lead to a precision approaching similar to 25% on a 2 km grid at 25 km. This worsens at higher altitudes because of reduced signal and at lower altitudes because of the reduced penetrability of the atmosphere. In terms of volume mixing ratio (VMR), the single profile precision increases from similar to 4 pptv at 17 km to similar to 8 pptv at 27 km. Repeatability, an alternative indicator of precision, is 2-3 pptv for SCIAMACHY retrievals and independent of altitude. The BrO stratospheric number density peak generally lies 5 +/- 2 km above the tropopause. In the tropics, the stratospheric BrO VMR generally increases with increasing altitude. The observed stratospheric BrO global distribution is generally consistent with previous balloon measurements but does not agree well with results of a model that uses Br-y inferred only from the observed breakdown of long-lived bromoalkanes (i.e., methyl bromide and halons). We find best agreement with the observed vertical and latitudinal distribution of BrO for model results that include an 8.4 +/- 2 pptv contribution to stratospheric Br-y, most of which is expected from the breakdown of VSL (very short lived) bromocarbons, in addition to the similar to 16 pptv contribution from longer-lived sources. This suggests that stratospheric Br-y exceeds 20 pptv. Profiles of Br-y profiles derived from the balloon measurements of BrO also suggest Br-y is in excess of 20 pptv, but the uncertainty and variability of these results do not allow us to definitively rule out this concentration. We find typical BrO VMRs of similar to 4 pptv at 15 km in the tropical tropopause layer, suggesting that a significant portion of the bromine from VSL bromoalkane sources may be carried across the tropopause in the form of inorganic decomposition products. We discuss a variety of VSL bromocarbons species that may be contributing to the elevated concentrations of stratospheric BrO. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Environm Canada, Meteorol Serv Canada, Toronto, ON M3H 5T4, Canada. Jet Prop Lab, Pasadena, CA 91109 USA. Belgian Inst Space Aeron, B-1180 Brussels, Belgium. CNRS, Serv Aeron, F-91371 Verrieres Le Buisson, France. Heidelberg Univ, Inst Environm Phys, D-69117 Heidelberg, Germany. Univ Bremen, Inst Environm Phys, D-28359 Bremen, Germany. European Space Agcy, European Space Res & Technol Ctr, NL-2200 AG Noordwijk, Netherlands. RP Sioris, CE (reprint author), Univ Saskatchewan, Inst Space & Atmospher Studies, Saskatoon, SK S7N 5E2, Canada. EM csioris@cfa.harvard.edu RI Salawitch, Ross/B-4605-2009; McLinden, Chris/A-7710-2010; von Savigny, Christian/B-3910-2014; Liu, Xiong/P-7186-2014; Boesch, Hartmut/G-6021-2012; OI Salawitch, Ross/0000-0001-8597-5832; McLinden, Chris/0000-0001-5054-1380; Liu, Xiong/0000-0003-2939-574X; Chance, Kelly/0000-0002-7339-7577; Sioris, Christopher/0000-0003-1168-8755 NR 83 TC 42 Z9 42 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 JUL 19 PY 2006 VL 111 IS D14 AR D14301 DI 10.1029/2005JD006479 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 071DQ UT WOS:000239578700001 ER PT J AU Podesta, JJ AF Podesta, J. J. TI Statistical bias in periodograms derived from solar wind time series SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETOHYDRODYNAMIC TURBULENCE; SPECTRUM ESTIMATION AB [1] The bias in periodogram spectral estimators is computed as a function of the sample size N by assuming a model power spectrum that decays like f(-alpha) a at high frequencies. For alpha = 2, it is shown that when the aliasing of the measured power spectrum is properly taken into account the bias in the "raw'' periodogram is nearly independent of frequency for large N. For the range of values 1.7 less than or similar to alpha < 2, an upper bound on the bias is provided by the case alpha = 2. Theoretical calculations of the maximum absolute bias as a function of N are used to determine when the periodogram is approximately unbiased and when the bias is significant enough to require the use of a modified periodogram which incorporates data tapering, also called data windowing. For solar wind velocity data acquired by the ACE spacecraft and a chosen low frequency cutoff of 10(-7) Hz, the bias in periodogram spectral estimators is found to be less than 4% for sample sizes N greater than 2(16) = 65536. This corresponds to a 49 day record of 64 s data. C1 NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Greenbelt, MD 20771 USA. RP Podesta, JJ (reprint author), NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Code 612-2, Greenbelt, MD 20771 USA. EM jpodesta@solar.stanford.edu NR 14 TC 4 Z9 4 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-SPACE JI J. Geophys. Res-Space Phys. PD JUL 19 PY 2006 VL 111 IS A7 AR A07103 DI 10.1029/2005JA011233 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 071EU UT WOS:000239581900002 ER PT J AU Kim, MJ AF Kim, Min-Jeong TI Single scattering parameters of randomly oriented snow particles at microwave frequencies SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID DISCRETE-DIPOLE APPROXIMATION; DIFFERENCE TIME-DOMAIN; LIGHT-SCATTERING; ICE CRYSTALS; MELTING-LAYER; FORMULATION; ALGORITHM; CLOUDS; GRAINS; RADAR AB [ 1] To develop a generally applicable fast and accurate parameterization method for computations of single scattering parameters at microwave frequencies requires a thorough knowledge of how the ice particle shape affects the scattering parameters. This study computes single scattering parameters ( scattering cross sections (C-sca), absorption cross sections (C-abs), and asymmetry factors) of various nonspherical snow particles using the discrete dipole approximation (DDA) method and the T-matrix method to examine the sensitivity of scattering parameters to snow particles at frequencies between 95 GHz and 340 GHz. Results show that C-sca/pi r(eff)(2), C-abs/pi r(eff)(2), and asymmetry factors of complex particles at a fixed size parameter x = 2 pi r(eff)/lambda do not depend on the specific particle shapes when x is less than about 2.5. Here lambda is the wavelength and r(eff) is the radius of equal-volume ice spheres. The Mie theory may be used to compute the single scattering parameters of randomly oriented snow particles if radius of equal-volume ice spheres reff is known over this range. On the other hand, when x > 2.5, scattering parameters of nonspherical particles are sensitive to the particle shapes because they are in an anomalous diffraction regime. In this regime, particles have a smaller projected area for a given volume so that the "unfavorable'' interference effect grows, resulting in smaller minimum values of scattering cross sections and asymmetry factors. Single scattering parameters averaged over a Gamma size distribution show that scattering coefficients are sensitive to shapes and that differences are larger than 10% when pi D-m/lambda; the size parameter of the median mass diameter (D-m) is greater than 1. Single scattering albedo values do not show significant differences over most size parameter ranges considered in this study. Asymmetry factors are sensitive to particle shapes when pi D-m/lambda is greater than 2. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. RP Kim, MJ (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 614-6, Greenbelt, MD 20771 USA. EM mjkim@neptune.gsfc.nasa.gov NR 30 TC 38 Z9 38 U1 2 U2 5 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 JUL 18 PY 2006 VL 111 IS D14 AR D14201 DI 10.1029/2005JD006892 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 071DP UT WOS:000239578600002 ER PT J AU van Noije, TPC Eskes, HJ Dentener, FJ Stevenson, DS Ellingsen, K Schultz, MG Wild, O Amann, M Atherton, CS Bergmann, DJ Bey, I Boersma, KF Butler, T Cofala, J Drevet, J Fiore, AM Gauss, M Hauglustaine, DA Horowitz, LW Isaksen, ISA Krol, MC Lamarque, JF Lawrence, MG Martin, RV Montanaro, V Muller, JF Pitari, G Prather, MJ Pyle, JA Richter, A Rodriguez, JM Savage, NH Strahan, SE Sudo, K Szopa, S van Roozendael, M AF van Noije, T. P. C. Eskes, H. J. Dentener, F. J. Stevenson, D. S. Ellingsen, K. Schultz, M. G. Wild, O. Amann, M. Atherton, C. S. Bergmann, D. J. Bey, I. Boersma, K. F. Butler, T. Cofala, J. Drevet, J. Fiore, A. M. Gauss, M. Hauglustaine, D. A. Horowitz, L. W. Isaksen, I. S. A. Krol, M. C. Lamarque, J. -F. Lawrence, M. G. Martin, R. V. Montanaro, V. Mueller, J. - F. Pitari, G. Prather, M. J. Pyle, J. A. Richter, A. Rodriguez, J. M. Savage, N. H. Strahan, S. E. Sudo, K. Szopa, S. van Roozendael, M. TI Multi-model ensemble simulations of tropospheric NO2 compared with GOME retrievals for the year 2000 SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID CHEMICAL-TRANSPORT MODEL; OZONE MONITORING EXPERIMENT; RADIATIVE-TRANSFER MODEL; AIRCRAFT MOZAIC DATA; SATELLITE-OBSERVATIONS; NITROGEN-DIOXIDE; NONMETHANE HYDROCARBONS; SURFACE REFLECTIVITY; GLOBAL DISTRIBUTIONS; 3-DIMENSIONAL MODEL AB We present a systematic comparison of tropospheric NO2 from 17 global atmospheric chemistry models with three state-of-the-art retrievals from the Global Ozone Monitoring Experiment (GOME) for the year 2000. The models used constant anthropogenic emissions from IIASA/EDGAR3.2 and monthly emissions from biomass burning based on the 1997 - 2002 average carbon emissions from the Global Fire Emissions Database (GFED). Model output is analyzed at 10: 30 local time, close to the overpass time of the ERS-2 satellite, and collocated with the measurements to account for sampling biases due to incomplete spatiotemporal coverage of the instrument. We assessed the importance of different contributions to the sampling bias: correlations on seasonal time scale give rise to a positive bias of 30 - 50% in the retrieved annual means over regions dominated by emissions from biomass burning. Over the industrial regions of the eastern United States, Europe and eastern China the retrieved annual means have a negative bias with significant contributions ( between - 25% and + 10% of the NO2 column) resulting from correlations on time scales from a day to a month. We present global maps of modeled and retrieved annual mean NO2 column densities, together with the corresponding ensemble means and standard deviations for models and retrievals. The spatial correlation between the individual models and retrievals are high, typically in the range 0.81 - 0.93 after smoothing the data to a common resolution. On average the models underestimate the retrievals in industrial regions, especially over eastern China and over the Highveld region of South Africa, and overestimate the retrievals in regions dominated by biomass burning during the dry season. The discrepancy over South America south of the Amazon disappears when we use the GFED emissions specific to the year 2000. The seasonal cycle is analyzed in detail for eight different continental regions. Over regions dominated by biomass burning, the timing of the seasonal cycle is generally well reproduced by the models. However, over Central Africa south of the Equator the models peak one to two months earlier than the retrievals. We further evaluate a recent proposal to reduce the NOx emission factors for savanna fires by 40% and find that this leads to an improvement of the amplitude of the seasonal cycle over the biomass burning regions of Northern and Central Africa. In these regions the models tend to underestimate the retrievals during the wet season, suggesting that the soil emissions are higher than assumed in the models. In general, the discrepancies between models and retrievals cannot be explained by a priori profile assumptions made in the retrievals, neither by diurnal variations in anthropogenic emissions, which lead to a marginal reduction of the NO2 abundance at 10: 30 local time ( by 2.5 - 4.1% over Europe). Overall, there are significant differences among the various models and, in particular, among the three retrievals. The discrepancies among the retrievals ( 10 - 50% in the annual mean over polluted regions) indicate that the previously estimated retrieval uncertainties have a large systematic component. Our findings imply that top-down estimations of NOx emissions from satellite retrievals of tropospheric NO2 are strongly dependent on the choice of model and retrieval. C1 Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. European Commiss, Joint Res Ctr, Inst Environm & Sustaiinabil, Ispra, Italy. Univ Edinburgh, Sch Geosci, Edinburgh, Midlothian, Scotland. Univ Oslo, Dept Geosci, Oslo, Norway. Max Planck Inst Meteorol, Hamburg, Germany. JAMSTEC, Frontier Res Ctr Global Change, Yokohama, Kanagawa, Japan. Univ Cambridge, Ctr Atmospher Sci, Cambridge CB2 1TN, England. Int Inst Appl Syst Anal, A-2361 Laxenburg, Austria. Lawrence Livermore Natl Lab, Div Atmospher Sci, Livermore, CA USA. Ecole Polytech Fed Lausanne, CH-1015 Lausanne, Switzerland. Max Planck Inst Chem, Mainz, Germany. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ USA. Lab Sci Climat & Environm, Gif Sur Yvette, France. Space Res Org Netherlands, Utrecht, Netherlands. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Dalhousie Univ, Dept Phys & Atmospher Sci, Halifax, NS, Canada. Smithsonian Astrophys Observ, Cambridge, MA USA. Univ Aquila, Dipartimento Fis, I-67100 Laquila, Italy. Belgian Inst Space Aeron, Brussels, Belgium. Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA USA. Univ Bremen, Inst Environm Phys, Bremen, Germany. Goddard Earth Sci & Technol Ctr, Washington, DC USA. RP van Noije, TPC (reprint author), Royal Netherlands Meteorol Inst, POB 201, NL-3730 AE De Bilt, Netherlands. EM noije@knmi.nl RI Martin, Randall/C-1205-2014; Krol, Maarten/E-3414-2013; Horowitz, Larry/D-8048-2014; Lamarque, Jean-Francois/L-2313-2014; Schultz, Martin/I-9512-2012; Martin, Randall/A-2051-2008; Wild, Oliver/A-4909-2009; Szopa, Sophie/F-8984-2010; Krol, Maarten/B-3597-2010; Richter, Andreas/C-4971-2008; Bergmann, Daniel/F-9801-2011; Butler, Tim/G-1139-2011; Stevenson, David/C-8089-2012; Strahan, Susan/H-1965-2012; Boersma, Klaas/H-4559-2012; Magana, Felipe/B-6966-2013; Rodriguez, Jose/G-3751-2013 OI Martin, Randall/0000-0003-2632-8402; Horowitz, Larry/0000-0002-5886-3314; Lamarque, Jean-Francois/0000-0002-4225-5074; Schultz, Martin/0000-0003-3455-774X; Pitari, Giovanni/0000-0001-7051-9578; Wild, Oliver/0000-0002-6227-7035; Szopa, Sophie/0000-0002-8641-1737; Richter, Andreas/0000-0003-3339-212X; Bergmann, Daniel/0000-0003-4357-6301; Stevenson, David/0000-0002-4745-5673; Boersma, Klaas/0000-0002-4591-7635; Rodriguez, Jose/0000-0002-1902-4649 NR 96 TC 87 Z9 87 U1 42 U2 83 PU COPERNICUS GESELLSCHAFT MBH PI GOTTINGEN PA BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY SN 1680-7316 EI 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JUL 17 PY 2006 VL 6 BP 2943 EP 2979 PG 37 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 065CO UT WOS:000239137200002 ER PT J AU Bakunov, MI Maslov, AV Bodrov, SB AF Bakunov, M. I. Maslov, A. V. Bodrov, S. B. TI Below-band-gap excitation of a terahertz surface plasmon-polariton SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GENERATION; WAVE AB We analyze the excitation of a surface plasmon-polariton at terahertz frequencies by an optical pulse with tilted intensity front incident on a semiconductor surface. We show that one can achieve an order of magnitude increase in the generated terahertz power by using an optical pulse with frequencies below the band gap compared to the above-band-gap excitation. (c) 2006 American Institute of Physics. C1 Univ Nizhny Novgorod, Dept Radiophys, Nizhnii Novgorod 603950, Russia. Russian Acad Sci, Inst Appl Phys, Nizhnii Novgorod 603950, Russia. NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Bakunov, MI (reprint author), Univ Nizhny Novgorod, Dept Radiophys, Nizhnii Novgorod 603950, Russia. EM bakunov@rf.unn.ru RI Maslov, Alexey/E-5158-2011; Bodrov, Sergey/D-1962-2012; Bakunov, Michael/E-2875-2017 OI Maslov, Alexey/0000-0002-7835-2474; Bakunov, Michael/0000-0002-4209-1372 NR 6 TC 2 Z9 2 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 15 PY 2006 VL 100 IS 2 AR 026106 DI 10.1063/1.2218028 PG 3 WC Physics, Applied SC Physics GA 069CR UT WOS:000239423400164 ER PT J AU Gobron, N Pinty, B Aussedat, O Chen, JM Cohen, WB Fensholt, R Gond, V Huemmrich, KF Lavergne, T Melin, F Privette, JL Sandholt, I Taberner, M Turner, DP Verstraete, MM Widlowski, JL AF Gobron, Nadine Pinty, Bernard Aussedat, Ophelie Chen, Jing M. Cohen, Warren B. Fensholt, Rasmus Gond, Valery Huemmrich, Karl Fred Lavergne, Thomas Melin, Frederic Privette, Jeffrey L. Sandholt, Inge Taberner, Malcolm Turner, David P. Verstraete, Michel M. Widlowski, Jean-Luc TI Evaluation of fraction of absorbed photosynthetically active radiation products for different canopy radiation transfer regimes: Methodology and results using Joint Research Center products derived from SeaWiFS against ground-based estimations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LEAF-AREA INDEX; OPTIMAL SPECTRAL INDEXES; MODIS LAI; SPATIAL HETEROGENEITY; OPTICAL MEASUREMENTS; FOREST SITE; MISR DATA; VEGETATION; REFLECTANCE; ALGORITHM AB [ 1] This paper discusses the quality and the accuracy of the Joint Research Center (JRC) fraction of absorbed photosynthetically active radiation (FAPAR) products generated from an analysis of Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data. The FAPAR value acts as an indicator of the presence and state of the vegetation and it can be estimated from remote sensing measurements using a physically based approach. The quality of the SeaWiFS FAPAR products assessed in this paper capitalizes on the availability of a 6-year FAPAR time series over the full globe. This evaluation exercise is performed in two phases involving, first, an analysis of the verisimilitude of the FAPAR products under documented environmental conditions and, second, a direct comparison of the FAPAR values with ground-based estimations where and when the latter are available. This second phase is conducted following a careful analysis of problems arising for performing such a comparison. This results in the grouping of available field information into broad categories representing different radiative transfer regimes. This strategy greatly helps the interpretation of the results since it recognizes the various levels of difficulty and sources of uncertainty associated with the radiative sampling of different types of vegetation canopies. C1 Commiss European Communities, Joint Res Ctr, IES, Global Environm Monitoring Unit, I-21020 Ispra, VA, Italy. Univ Toronto, Dept Geog, Toronto, ON M5S 3G3, Canada. Univ Toronto, Program Planning, Toronto, ON M5S 3G3, Canada. US Forest Serv, USDA, Corvallis, OR 97331 USA. Univ Copenhagen, Inst Geog, DK-1350 Copenhagen, Denmark. Ctr Cooperat Int Rech Agron Dev, Forest Dept, Cayenne 97323, French Guiana. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Oregon State Univ, Dept Forest Sci, Corvallis, OR 97331 USA. RP Gobron, N (reprint author), Commiss European Communities, Joint Res Ctr, IES, Global Environm Monitoring Unit, TP 440,Via E Fermi, I-21020 Ispra, VA, Italy. EM nadine.gobron@jrc.it RI Privette, Jeffrey/G-7807-2011; Fensholt, Rasmus/L-7951-2014; OI Privette, Jeffrey/0000-0001-8267-9894; Fensholt, Rasmus/0000-0003-3067-4527; Verstraete, Michel/0000-0003-0968-8721 NR 50 TC 85 Z9 88 U1 3 U2 25 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 JUL 15 PY 2006 VL 111 IS D13 AR D13110 DI 10.1029/2005JD006511 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 066GI UT WOS:000239217300005 ER PT J AU Kazantzidis, A Bais, AF Grobner, J Herman, JR Kazadzis, S Krotkov, N Kyro, E den Outer, PN Garane, K Gorts, P Lakkala, K Meleti, C Slaper, H Tax, RB Turunen, T Zerefos, CS AF Kazantzidis, A. Bais, A. F. Groebner, J. Herman, J. R. Kazadzis, S. Krotkov, N. Kyro, E. den Outer, P. N. Garane, K. Gorts, P. Lakkala, K. Meleti, C. Slaper, H. Tax, R. B. Turunen, T. Zerefos, C. S. TI Comparison of satellite-derived UV irradiances with ground-based measurements at four European stations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TOTAL OZONE; SOLAR UV; RADIATION; SURFACE; SPECTRORADIOMETER; RETRIEVALS; REDUCTION; AEROSOLS; CLOUDS AB [ 1] Satellite-derived ultraviolet (UV) irradiances may form the basis for establishing a global UV climatology, provided that their accuracy is confirmed against ground-based measurements of known quality. In this study, quality-checked spectral UV irradiance measurements from four European stations (Sodankyla, Finland; Bilthoven, Netherlands; Ispra, Italy; and Thessaloniki, Greece) are compared with those derived from TOMS, based on the ( version 8) data set. The aim of this study is to validate the TOMS UV irradiances and to investigate the origin of disagreements with ground-based data. Comparisons showed that TOMS overestimates summertime noon CIE-weighted irradiances from 6.6% at the high-latitude site of Sodankyla up to 19% for the three other sites. The influence of clouds and aerosols on the observed differences was investigated. For the other three sites ( Bilthoven, Ispra, and Thessaloniki), TOMS overestimates the irradiance at 324 nm by almost 15% even under conditions with cloud optical depth of less than 5. For cloud-free days at Ispra and Thessaloniki, differences ranging between 3% and 20% are well correlated with aerosol optical depth. C1 Aristotle Univ Thessaloniki, Lab Atmospher Phys, GR-54124 Thessaloniki, Greece. World Radiat Ctr, Phys Meteorol Observ Davos, CH-7260 Davos, Switzerland. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Finnish Meteorol Inst, Arctic Res Ctr, FIN-99600 Sodankyla, Finland. Natl Inst Publ Hlth & Environm, Radiat Res Lab, NL-3720 BA Bilthoven, Netherlands. Univ Athens, Fac Geol & Geoenvironm, Climatol Lab, GR-15784 Athens, Greece. RP Kazantzidis, A (reprint author), Aristotle Univ Thessaloniki, Lab Atmospher Phys, Campus Box 149, GR-54124 Thessaloniki, Greece. EM akaza@auth.gr RI Kazadzis, Stelios/A-5628-2011; Kazadzis, Stelios/F-8667-2011; Bais, Alkiviadis/D-2230-2009; Krotkov, Nickolay/E-1541-2012; OI Bais, Alkiviadis/0000-0003-3899-2001; Krotkov, Nickolay/0000-0001-6170-6750; Kazadzis, Stelios/0000-0002-8624-8247; Herman, Jay/0000-0002-9146-1632 NR 21 TC 31 Z9 31 U1 0 U2 2 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 JUL 15 PY 2006 VL 111 IS D13 AR D13207 DI 10.1029/2005JD006672 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 066GI UT WOS:000239217300006 ER PT J AU Roger, JC Mallet, M Dubuisson, P Cachier, H Vermote, E Dubovik, O Despiau, S AF Roger, J. C. Mallet, M. Dubuisson, P. Cachier, H. Vermote, E. Dubovik, O. Despiau, S. TI A synergetic approach for estimating the local direct aerosol forcing: Application to an urban zone during the Experience sur Site pour Contraindre les Modeles de Pollution et de Transport d'Emission (ESCOMPTE) experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID INDIAN-OCEAN EXPERIMENT; OBSERVATIONAL EXPERIMENT TARFOX; RADIATIVE-TRANSFER; OPTICAL-PROPERTIES; ACE-ASIA; MULTIPLE-SCATTERING; MIXING STATE; SATELLITE; SURFACE; ABSORPTION AB [1] A method dedicated to the investigation of direct radiative forcing of the main anthropogenic aerosol species ( ammonium sulfate, black carbon, particulate organic matter) is presented. We computed the direct radiative aerosol forcing at the top of atmosphere (TOA), at the bottom of atmosphere ( BOA), and into the atmospheric layer (ATM). The methodology is based on chemical, photometric, and satellite measurements. We first determined the optical properties of the main aerosol species and then computed their direct radiative impact at local scale. The method was applied to a periurban zone during the Experience sur Site pour Contraindre les Modeles de Pollution et de Transport d'Emission experiment. Optical computations indicate that the single scattering albedo, for the total aerosol population in the external mixture, is equal to 0.83 +/- 0.04 at 550 nm, indicative of a strong absorption of the solar radiation. At the same time the mean asymmetry parameter is equal to 0.59 +/- 0.04, and the mean aerosol optical thickness is equal to 0.30 +/- 0.02, at 550 nm. The anthropogenic urban aerosol layer reduces significantly the daily surface illumination ( - 24 W m(-2) > Delta F-BOA > - 47.5 W m(-2)) by reflection to space (-6 W m(-2) > Delta F-TOA > - 9 W m(-2)) and by absorption of the solar radiation into the atmosphere (17 W m(-2) < Delta F-ATM < 39 W m(-2)). The available resulting energy in the atmospheric column heats the lowermost part of the atmosphere from 1.1 degrees K d(-1) to 2.8 degrees K d(-1). Our study shows that the black carbon particles have a large contribution to the BOA forcing ( almost 50% of the total daily forcing), whereas the ammonium sulfate particles contribute only to about 10%. Conversely, the TOA daily forcing is mostly driven by the ammonium sulfate aerosol ( around 50%). C1 Univ Maryland, Dept Geog, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Littoral Cote Opale, ELICO, CNRS, UMR 8013, F-62930 Wimereux, France. Observ Midi Pyrenees, Lab Aerol, UMR 5560, F-31400 Toulouse, France. CEA, LSCE, CNRS, UMR 1572, F-91191 Gif Sur Yvette, France. Univ Toulon & Var, LEPI, CNRS, UMR 6017, F-83957 La Garde, France. RP Roger, JC (reprint author), Univ Maryland, Dept Geog, College Pk, MD 20742 USA. EM jc@ltdri.org RI Dubovik, Oleg/A-8235-2009; Vermote, Eric/K-3733-2012 OI Dubovik, Oleg/0000-0003-3482-6460; NR 38 TC 42 Z9 42 U1 0 U2 1 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 JUL 15 PY 2006 VL 111 IS D13 AR D13208 DI 10.1029/2005JD006361 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 066GI UT WOS:000239217300002 ER PT J AU Cravens, TE Clark, J Bhardwaj, A Elsner, R Waite, JH Maurellis, AN Gladstone, GR Branduardi-Raymont, G AF Cravens, T. E. Clark, J. Bhardwaj, A. Elsner, R. Waite, J. H., Jr. Maurellis, A. N. Gladstone, G. R. Branduardi-Raymont, G. TI X-ray emission from the outer planets: Albedo for scattering and fluorescence of solar X rays SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID EUV IRRADIANCE; XMM-NEWTON; JUPITER; CHANDRA; DISCOVERY; SATURN; AURORA; PRECIPITATION; ULTRAVIOLET; ATMOSPHERE AB [ 1] Soft X-ray emission has been observed from the low-latitude "disk'' of both Jupiter and Saturn as well as from the auroral regions of these planets. The disk emission as observed by ROSAT, the Chandra X-Ray Observatory, and XMM-Newton appears to be uniformly distributed across the disk and to be correlated with solar activity. These characteristics suggest that the disk X rays are produced by ( 1) the elastic scattering of solar X rays by atmospheric neutrals and ( 2) the absorption of solar X rays in the carbon K-shell followed by fluorescent emission. The carbon atoms are found in methane molecules located below the homopause. In this paper we present the results of calculations of the scattering albedo for soft X rays. We also show the calculated X-ray intensity for a range of atmospheric abundances for Jupiter and Saturn and for a number of solar irradiance spectra. The model calculations are compared with recent X-ray observations of Jupiter and Saturn. We conclude that the emission of soft X rays from the disks of Jupiter and Saturn can be largely explained by the scattering and fluorescence of solar soft X rays. We suggest that measured X-ray intensities from the disk regions of Jupiter and Saturn can be used to constrain both the absolute intensity and the spectrum of solar X rays. C1 Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48105 USA. Space Res Org Netherlands, Div Earth Oriented Sci, NL-3584 CA Utrecht, Netherlands. SW Res Inst, San Antonio, TX 78284 USA. UCL, Mullard Space Sci Lab, Surrey, England. RP Cravens, TE (reprint author), Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. EM cravens@ku.edu; anil.bhardwaj@msfc.nasa.gov; ron.elsner@msfc.nasa.gov; hunterw@umich.edu; ahilleas@gmail.com; randy.gladstone@swri.org OI Bhardwaj, Anil/0000-0003-1693-453X NR 37 TC 15 Z9 15 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 JUL 15 PY 2006 VL 111 IS A7 AR A07308 DI 10.1029/2005JA011413 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 066HL UT WOS:000239220200002 ER PT J AU Tsurutani, BT McPherron, RL Gonzalez, WD Lu, G Sobral, JHA Gopalswamy, N AF Tsurutani, Bruce T. McPherron, Robert L. Gonzalez, Walter D. Lu, Gang Sobral, Jose H. A. Gopalswamy, Nat TI Introduction to special section on corotating solar wind streams and recurrent geomagnetic activity SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Editorial Material ID HILDCAA EVENTS; CORONAL HOLE; VELOCITY; REGIONS C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. Inst Nacl Pesquisas Espaciais, So Reg Space Res Ctr, BR-12201 Sao Jose Dos Campos, SP, Brazil. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tsurutani, BT (reprint author), CALTECH, Jet Prop Lab, MS169-506,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM bruce.tsurutani@jpl.nasa.gov RI Gopalswamy, Nat/D-3659-2012 NR 24 TC 9 Z9 9 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-SPACE JI J. Geophys. Res-Space Phys. PD JUL 15 PY 2006 VL 111 IS A7 AR A07S00 DI 10.1029/2006JA011745 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 066HL UT WOS:000239220200007 ER PT J AU Krizmanic, JF Cherry, ML Streitmatter, RE AF Krizmanic, John F. Cherry, Michael L. Streitmatter, Robert E. TI Simulation studies of delta-ray backgrounds in a Compton-Scatter Transition Radiation Detector SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 3rd Workshop on Advanced Transition Radiation Detectors for Accelerators and Space Applications CY SEP 07-10, 2005 CL Brindisi, ITALY DE transition radiation; Compton scattering; delta rays; cosmic rays; ACCESS AB In order to evaluate the response to cosmic-ray nuclei of a Compton-Scatter Transition Radiation Detector in the proposed ACCESS space-based mission, a hybrid Monte Carlo simulation using GEANT3 and an external transition radiation (TR) generator routine was constructed. This simulation was employed to study the effects of delta-ray production induced by high-energy nuclei and to maximize the ratio of TR to delta-ray background. The results demonstrate the ability of a Compton-Scatter Transition Radiation Detector to measure nuclei from boron to iron up to Lorentz factors gamma similar to 10(5), taking into account the steeply falling power-law cosmic ray spectra. (c) 2006 Elsevier B.V. All fights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. EM jfk@cosmicra.gsfc.nasa.gov NR 7 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 15 PY 2006 VL 563 IS 2 BP 303 EP 305 DI 10.1016/j.nima.2006.02.164 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 065KT UT WOS:000239159500004 ER PT J AU Goodman, J Pugh, B Grob, E AF Goodman, Jack Pugh, Brett Grob, Eric TI Environmental (thermal) testing of space instrumentation: The GLAST example SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 3rd Workshop on Advanced Transition Radiation Detectors for Accelerators and Space Applications CY SEP 07-10, 2005 CL Brindisi, ITALY DE thermal tests; thermal-vacuum tests; environmental tests; space-bound instrumentation AB Space-bound scientific instruments are subjected to extensive ground testing before launch to ensure successful launch and on-orbit operation. This is a radical departure from testing terrestrial laboratory instruments since these instruments typically operate in a more benign environment., and are generally accessible for repair during their useful life. Among the various tests conducted for space environmental testing are thermal, structural (including vibration and acoustic) and electromagnetic interference (EMI). While all these tests are important, this paper concentrates only on the thermal tests. The intent of this paper is to provide a description of ground environmental thermal testing requirements necessary for successful launch and operation of space scientific instruments. This paper summarizes the scope, objectives and value for the various levels of thermal tests commonly performed on space-bound instrumentation, using Gamma-ray Large Area Space Telescope (GLAST) as an example. (c) 2006 Elsevier B.V. All rights reserved. C1 Stanford Linear Accelerator Ctr, Ingenium Associates, GLAST, LAT Instrument Program, Menlo Pk, CA 94025 USA. GLAST Program, Swales Aerosp, Pasadena, CA 91107 USA. NASA, Goddard Space Flight Ctr, GLAST Project, Washington, DC 20546 USA. RP Goodman, J (reprint author), Stanford Linear Accelerator Ctr, Ingenium Associates, GLAST, LAT Instrument Program, 408-505-3413, Menlo Pk, CA 94025 USA. EM jackg@slac.stanford.edu; BPugh@swales.com; Eric.W.Grob@nasa.gov NR 4 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 15 PY 2006 VL 563 IS 2 BP 377 EP 380 DI 10.1016/j.nima.2006.02.153 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 065KT UT WOS:000239159500020 ER PT J AU Bindschadler, R AF Bindschadler, Robert TI The environment and evolution of the West Antarctic ice sheet: setting the stage SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article; Proceedings Paper CT Royal-Society Discussion Meeting on Evolution of the Antarctic Ice Sheet CY OCT 17-18, 2005 CL London, ENGLAND DE West Antarctica; ice sheet; glaciology; ice sheet dynamics ID GROUNDING-LINE RETREAT; STREAM-B; PINE ISLAND; SIPLE DOME; BENEATH; SHELF; VARIABILITY; PENINSULA; DISCHARGE; FUTURE AB The West Antarctic ice sheet is the last ice sheet of the type cradled in a warm, marine geologic basin. Its perimeter stretches into the surrounding seas allowing warmer ocean waters to reach the undersides of its floating ice shelves and its relatively low surface elevation permits snow-carrying storms to extend well into its interior. This special environment has given rise to theories of impending collapse and for the past quarter-century has challenged researchers who seek a quantitative prediction of its future behaviour and the corresponding effect on sea level. Observations confirm changes on a variety of time scales from the quaternary to less than a minute. The dynamics of the ice sheet involve the complex interaction of ice that is warm at its base and cold along the margins of ice streams; subglacial till that is composed of a combination of marine sediment and eroded sedimentary rocks; and water that moves primarily between the ice and bed, but whose flow direction can differ from the direction of ice motion. The pressure of the water system is often sufficient to float the ice sheet locally and small changes in the amount of water in the till can cause it to rapidly switch from very weak to very stiff. C1 NASA, Goddard Space Flight Ctr, Hydrospher & Biospher Sci Lab, Greenbelt, MD 20771 USA. RP Bindschadler, R (reprint author), NASA, Goddard Space Flight Ctr, Hydrospher & Biospher Sci Lab, Greenbelt, MD 20771 USA. EM robert.a.bindschadler@nasa.gov NR 59 TC 20 Z9 20 U1 2 U2 10 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-503X EI 1471-2962 J9 PHILOS T R SOC A JI Philos. Trans. R. Soc. A-Math. Phys. Eng. Sci. PD JUL 15 PY 2006 VL 364 IS 1844 BP 1583 EP 1605 DI 10.1098/rsta.2006.1790 PG 23 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 062KZ UT WOS:000238944500002 PM 16782601 ER PT J AU Rignot, E AF Rignot, Eric TI Changes in ice dynamics and mass balance of the Antarctic ice sheet SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article; Proceedings Paper CT Royal-Society Discussion Meeting on Evolution of the antarctic Ice Sheet CY OCT 17-18, 2005 CL London, ENGLAND DE Antarctica; interferometry; Southern Ocean; polar climate ID PINE-ISLAND GLACIER; AMUNDSEN SEA SECTOR; WEST ANTARCTICA; RADAR INTERFEROMETRY; BREAK-UP; CLIMATE VARIABILITY; SHELF COLLAPSE; LEVEL RISE; POLAR ICE; PENINSULA AB The concept that the Antarctic ice sheet changes with eternal slowness has been challenged by recent observations from satellites. Pronounced regional warming in the Antarctic Peninsula triggered ice shelf collapse, which led to a 10-fold increase in glacier flow and rapid ice sheet retreat. This chain of events illustrated the vulnerability of ice shelves to climate warming and their buffering role on the mass balance of Antarctica. In West Antarctica, the Pine Island Bay sector is draining far more ice into the ocean than is stored upstream from snow accumulation. This sector could raise sea level by I m and trigger widespread retreat of ice in West Antarctica. Pine Island Glacier accelerated 38% since 1975, and most of the speed up took place over the last decade. Its neighbour Thwaites Glacier is widening up and may double its width when its weakened eastern ice shelf breaks up. Widespread acceleration in this sector may be caused by glacier ungrounding from ice shelf melting by an ocean that has recently warmed by 0.3 degrees C. In contrast, glaciers buffered from oceanic change by large ice shelves have only small contributions to sea level. In East Antarctica, many glaciers are close to a state of mass balance, but sectors grounded well below sea level, such as Cook Ice Shelf, Ninnis/Mertz, Frost and Totten glaciers, are thinning and losing mass. Hence, East Antarctica is not immune to changes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rignot, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-319, Pasadena, CA 91109 USA. EM eric.rignot@jpl.nasa.gov RI Rignot, Eric/A-4560-2014 OI Rignot, Eric/0000-0002-3366-0481 NR 70 TC 65 Z9 67 U1 5 U2 31 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 JUL 15 PY 2006 VL 364 IS 1844 BP 1637 EP 1655 DI 10.1098/rsta.2006.1793 PG 19 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 062KZ UT WOS:000238944500005 PM 16782604 ER PT J AU Schaepman-Strub, G Schaepman, ME Painter, TH Dangel, S Martonchik, JV AF Schaepman-Strub, G. Schaepman, M. E. Painter, T. H. Dangel, S. Martonchik, J. V. TI Reflectance quantities in optical remote sensing-definitions and case studies SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE reflectance; terminology; definition; nomenclature; BRDF; spectrodirectional; vegetation; snow ID BIDIRECTIONAL REFLECTANCE; DIRECTIONAL REFLECTANCE; LAND-SURFACE; RADIATIVE-TRANSFER; GRAIN-SIZE; BRDF MODEL; VEGETATION; ALBEDO; SNOW; VARIABILITY AB The remote sensing community puts major efforts into calibration and validation of sensors, measurements, and derived products to quantify and reduce uncertainties. Given recent advances in instrument design, radiometric calibration, atmospheric correction, algorithm development, product development, validation, and delivery, the lack of standardization of reflectance terminology and products becomes a considerable source of error. This article provides full access to the basic concept and definitions of reflectance quantities, as given by Nicodemus et al. [Nicodemus, F.E., Richmond, J.C., Hsia, J.J., Ginsberg, I.W., and Limperis, T. (1977). Geometrical Considerations and Nomenclature for Reflectance. In: National Bureau of Standards, US Department of Commerce, Washington, D.C. URL: http://physics.nist.gov/Divisions/Div844/facilities/specphoto/pdf/geoConsid.pdf.] and Martonchik et al. [Martonchik, J.V, Bruegge, C.J., and Strahler, A. (2000). A review of reflectance nomenclature used in remote sensing. Remote Sensing Reviews, 19, 9-20.]. Reflectance terms such as BRDF, HDRF, BRF, BHR, DHR, black-sky albedo, white-sky albedo, and blue-sky albedo are defined, explained, and exemplified, while separating conceptual from measurable quantities. We use selected examples from the peer-reviewed literature to demonstrate that very often the current use of reflectance terminology does not fulfill physical standards and can lead to systematic errors. Secondly, the paper highlights the importance of a proper usage of definitions through quantitative comparison of different reflectance products with special emphasis on wavelength dependent effects. Reflectance quantities acquired under hemispherical illumination conditions (i.e., all outdoor measurements) depend not only on the scattering properties of the observed surface, but as well on atmospheric conditions, the object's surroundings, and the topography, with distinct expression of these effects in different wavelengths. We exemplify differences between the hemispherical and directional illumination quantities, based on observations (i.e., MISR), and on reflectance simulations of natural surfaces (i.e., vegetation canopy and snow cover). In order to improve the current situation of frequent ambiguous usage of reflectance terms and quantities, we suggest standardizing the terminology in reflectance product descriptions and that the community carefully utilizes the proposed reflectance terminology in scientific publications. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Wageningen & Res Ctr, Nat Conservat & Plant Ecol Grp, NL-6708 PD Wageningen, Netherlands. Univ Zurich, Dept Geog, RSL, CH-8057 Zurich, Switzerland. Univ Wageningen & Res Ctr, Ctr Geoinformat, NL-6700 AA Wageningen, Netherlands. Univ Colorado, NSIDC, Boulder, CO 80309 USA. Jet Propuls Lab, Pasadena, CA 91109 USA. RP Schaepman-Strub, G (reprint author), Univ Wageningen & Res Ctr, Nat Conservat & Plant Ecol Grp, Bornsesteeg 69, NL-6708 PD Wageningen, Netherlands. EM Gabriela.Schaepman@wur.nl RI Schaepman-Strub, Gabriela/D-8785-2011; Painter, Thomas/B-7806-2016; Schaepman, Michael/B-9213-2009 OI Schaepman, Michael/0000-0002-9627-9565 NR 61 TC 389 Z9 396 U1 19 U2 109 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 EI 1879-0704 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JUL 15 PY 2006 VL 103 IS 1 BP 27 EP 42 DI 10.1016/j.rse.2006.03.002 PG 16 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 061VL UT WOS:000238901000003 ER PT J AU Garrigues, S Allard, D Baret, F Weiss, M AF Garrigues, S. Allard, D. Baret, F. Weiss, M. TI Quantifying spatial heterogeneity at the landscape scale using variograrn models SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE spatial heterogeneity; moderate spatial resolution; variogram model; landscape; NDVI; length scale; data regularization; optimal spatial resolution ID REMOTE-SENSING ALGORITHMS; DIGITAL IMAGES; AUTO-CORRELATION; SCENE MODELS; RESOLUTION; REGULARIZATION; DECOMPOSITION; VALIDATION; VARIANCE; FOREST AB The monitoring of earth surface dynamic processes at a global scale requires high temporal frequency remote sensing observations which are provided up to now by moderate spatial resolution sensors. However, the spatial heterogeneity within the moderate spatial resolution pixel biases non-linear estimation processes of land surface variables from remote sensing data. To limit its influence on the description of land surface processes, corrections based on the quantification of the intra-pixel heterogeneity may be applied to non-linear estimation processes. A complementary strategy is to define the proper pixel size to capture the spatial variability of the data and minimize the intra-pixel variability. This work provides a methodology to characterize and quantify the spatial heterogeneity of landscape vegetation cover from the modeling of the variogram of high spatial resolution NDVI data. NDVI variograms for 18 landscapes extracted from the VALERI database show that the land use is the main factor of spatial variability as quantified by the variogram sill. Crop sites are more heterogeneous than natural vegetation and forest sites at the landscape level. The integral range summarizes all structural parameters of the variograin into a single characteristic area. Its square root quantifies the mean length scale (i.e. spatial scale) of the data, which varies between 216 and 1060 in over the 18 landscapes considered. The integral range is also used as a yardstick to judge if the size of an image is large enough to measure properly the length scales of the data with the variogram. We propose that it must be smaller than 5% of the image surface. The theoretical dispersion variance, computed from the variograin model, quantifies the spatial heterogeneity within a moderate resolution pixel. It increases rapidly with pixel size until this size is larger than the mean length scale of the data. Finally based on the analysis of 18 landscapes, the sufficient pixel size to capture the major part of the spatial variability of the vegetation cover at the landscape scale is estimated to be less than 100 m. Since for all the heterogeneous landscapes the loss of NDVI spatial variability was small at this spatial resolution, the bias generated by the intra-pixel spatial heterogeneity on non-linear estimation processes will be reduced. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Maryland, NASA, GSFC, Greenbelt, MD USA. INRA, Avignon, France. Noveltis, Toulouse, France. RP Garrigues, S (reprint author), Univ Maryland, NASA, GSFC, Greenbelt, MD USA. EM Sebastien.Garrigues@gsfc.nasa.gov RI Baret, Fred/C-4135-2011; OI Baret, Fred/0000-0002-7655-8997; Weiss, Marie/0000-0002-2341-667X NR 63 TC 101 Z9 118 U1 6 U2 29 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 EI 1879-0704 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JUL 15 PY 2006 VL 103 IS 1 BP 81 EP 96 DI 10.1016/j.rse.2006.03.013 PG 16 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 061VL UT WOS:000238901000007 ER PT J AU Shen, BW Atlas, R Reale, O Lin, SJ Chern, JD Chang, J Henze, C Li, JL AF Shen, B. -W. Atlas, R. Reale, O. Lin, S. -J. Chern, J. -D. Chang, J. Henze, C. Li, J. -L. TI Hurricane forecasts with a global mesoscale-resolving model: Preliminary results with Hurricane Katrina (2005) SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TROPICAL CYCLONES; COUPLED MODEL; SIMULATIONS; INTENSITY; PREDICTION AB It is known that General Circulation Models (GCMs) have insufficient resolution to accurately simulate hurricane near-eye structure and intensity. The increasing capabilities of high-end computers have changed this. The mesoscale-resolving finite-volume GCM (fvGCM) has been experimentally deployed on the NASA Columbia supercomputer, and its performance is evaluated in this study by choosing hurricane Katrina as an example. In late August 2005, Katrina underwent two stages of rapid intensification, and became the sixth most intense hurricane in the Atlantic. Six 5-day simulations of Katrina at both 0.25 degrees and 0.125 degrees show comparable track forecasts but the 0.125 degrees runs provide much better intensity forecasts, producing the center pressure with errors of only +/- 12 hPa. In the runs examined in this study, the 0.125 degrees simulates better near-eye wind distributions and a more realistic average intensification rate. To contribute to the ongoing research on the effects of disabling convection parameterization (CP), we present promising results by comparing 0.125 degrees runs with disabled CPs against runs with enabled CPs. C1 NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Applicat Int Corp, Beltsville, MD USA. NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Comp Sci Corp, Moffett Field, CA USA. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shen, BW (reprint author), NASA, Atmospheres Lab, Goddard Space Flight Ctr, Code 613, Greenbelt, MD 20771 USA. EM bo-wen.shen.1@gsfc.nasa.gov RI Atlas, Robert/A-5963-2011 OI Atlas, Robert/0000-0002-0706-3560 NR 19 TC 37 Z9 37 U1 1 U2 4 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 JUL 14 PY 2006 VL 33 IS 13 AR L13813 DI 10.1029/2006GL026143 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 066FR UT WOS:000239215600002 ER PT J AU Parkinson, CL Vinnikov, KY Cavalieri, DJ AF Parkinson, Claire L. Vinnikov, Konstantin Y. Cavalieri, Donald J. TI Evaluation of the simulation of the annual cycle of Arctic and Antarctic sea ice coverages by 11 major global climate models SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID CIRCULATION; VARIABILITY; ATMOSPHERE; SATELLITE; EXTENTS; TRENDS AB [1] Comparison of polar sea ice results from 11 major global climate models (GCMs) and satellite-derived observations for 1979 - 2004 reveals that each of the models is simulating annual cycles that are phased at least approximately correctly in both hemispheres. Each is also simulating various key aspects of the observed ice cover distributions, such as winter ice not only throughout the central Arctic basin but also throughout Hudson Bay, despite its relatively low latitudes. However, some of the models simulate too much ice, others simulate too little ice ( in some cases depending on hemisphere and/or season), and some match the observations better in one season versus another. Several models do noticeably better in the Northern Hemisphere than in the Southern Hemisphere, and one does noticeably better in the Southern Hemisphere. In the Northern Hemisphere all simulate monthly average ice extents to within +/- 5.1 x 10(6) km(2) of the observed ice extent throughout the year; in the Southern Hemisphere all except one simulate the monthly averages to within +/- 6.3 x 10(6) km(2) of the observed values. All the models properly simulate a lack of winter ice to the west of Norway; however, most obtain more ice immediately north of Norway than the observations show, suggesting an under simulation of the North Atlantic Current. The spread in monthly averaged ice extents among the 11 model simulations is greater in the Southern Hemisphere than in the Northern Hemisphere and greatest in the Southern Hemisphere winter and spring. C1 NASA, Goddard Space Flight Ctr, Cryospher Sci Branch, Greenbelt, MD 20771 USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. RP Parkinson, CL (reprint author), NASA, Goddard Space Flight Ctr, Cryospher Sci Branch, Code 614-1, Greenbelt, MD 20771 USA. EM claire.l.parkinson@nasa.gov RI Vinnikov, Konstantin/F-9348-2010; Parkinson, Claire/E-1747-2012 OI Parkinson, Claire/0000-0001-6730-4197 NR 32 TC 40 Z9 43 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-OCEANS JI J. Geophys. Res.-Oceans PD JUL 14 PY 2006 VL 111 IS C7 AR C07012 DI 10.1029/2005JC003408 PG 14 WC Oceanography SC Oceanography GA 066GS UT WOS:000239218300002 ER PT J AU Bansal, NP Zhong, ZM AF Bansal, Narottam P. Zhong, Zhimin TI Combustion synthesis of Sm0.5Sr0.5CoO3-x and La0.6Sr0.4CoO3-x nanopowders for solid oxide fuel cell cathodes SO JOURNAL OF POWER SOURCES LA English DT Article DE nanopowder; solid oxide fuel cells; cathodes; powder processing ID GLYCINE-NITRATE COMBUSTION; POWDERS AB Nanopowders of Sm0.5Sr0.5CoO3-x (SSC) and La0.6Sr0.4CoO3-x (LSC) compositions, which are being investigated as cathode materials for intermediate temperature solid oxide fuel cells (SOFC), were synthesized by a solution-combustion method using metal nitrates and glycine as fuel. Development of crystalline phases in the as-synthesized powders after heat treatments at various temperatures was monitored by X-ray diffraction (XRD). Perovskite phase in LSC formed more readily than in SSC. Single-phase perovskites were obtained after heat treatment of the combustion synthesized LSC and SSC powders at 1000 and 1200 degrees C, respectively. The as-synthesized powders had an average particle size of similar to 12nm as determined from X-ray line broadening analysis using the Scherrer equation. Average grain size of the powders increased with increase in calcination temperature. Morphological analysis of the powders calcined at various temperatures was done by scanning electron microscopy (SEM). (c) 2005 Elsevier B.V. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NASA, QSS Grp Inc, Glenn Res Ctr Grp, Cleveland, OH 44135 USA. RP Bansal, NP (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM Narottam.P.Bansal@nasa.gov NR 11 TC 85 Z9 87 U1 1 U2 49 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD JUL 14 PY 2006 VL 158 IS 1 BP 148 EP 153 DI 10.1016/j.jpowsour.2005.09.057 PG 6 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 062SG UT WOS:000238964200019 ER PT J AU Dwek, E AF Dwek, Eli TI Astronomy - The supernova origin of interstellar dust SO SCIENCE LA English DT Editorial Material C1 NASA, Goddard Space Flight Ctr, Observ Cosmol Lab, Greenbelt, MD 20771 USA. RP Dwek, E (reprint author), NASA, Goddard Space Flight Ctr, Observ Cosmol Lab, Code 661, Greenbelt, MD 20771 USA. EM eli.dwek@nasa.gov NR 9 TC 3 Z9 3 U1 1 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 JUL 14 PY 2006 VL 313 IS 5784 BP 178 EP 180 DI 10.1126/science.1130423 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 063GZ UT WOS:000239008000028 PM 16840686 ER PT J AU Morgan, DD Gurnett, DA Kirchner, DL Huff, RL Brain, DA Boynton, WV Acuna, MH Plaut, JJ Picardi, G AF Morgan, D. D. Gurnett, D. A. Kirchner, D. L. Huff, R. L. Brain, D. A. Boynton, W. V. Acuna, M. H. Plaut, J. J. Picardi, G. TI Solar control of radar wave absorption by the Martian ionosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID POLAR-CAP ABSORPTION; MARS AB The MARSIS active sounder aboard the Mars Express spacecraft, under certain conditions in the Martian ionosphere, fails to detect the planetary surface. We have generated a statistical measure of the surface reflection visibility, which we plot as a time series and compare with both in situ particle data taken at Mars and solar x-ray data taken at Earth. We show that loss of the surface signal is closely related to the influx of solar protons at tens of MeV energies. We infer that the influx of high energy solar protons causes impact ionization, increasing the electron density in the Martian ionosphere. At altitudes close to or below 100 km, where the electron-neutral collision frequency is high and the electron density typically has a local maximum, the increased electron density raises the damping coefficient to levels sufficient for complete absorption of the sounding wave over an altitude range of a few tens of kilometers. C1 Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Univ Calif Berkeley, Space Sci Lab, Space Phys Res Grp, Berkeley, CA 94720 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Jet Propuls Lab, Pasadena, CA 91109 USA. Univ Roma La Sapienza, Infocom Dept, I-00184 Rome, Italy. RP Morgan, DD (reprint author), Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. EM david-morgan@uiowa.edu NR 13 TC 30 Z9 30 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 JUL 13 PY 2006 VL 33 IS 13 AR L13202 DI 10.1029/2006GL026637 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 066FP UT WOS:000239215400007 ER PT J AU Vestrand, WT Wren, JA Wozniak, PR Aptekar, R Golentskii, S Pal'shin, V Sakamoto, T White, RR Evans, S Casperson, D Fenimore, E AF Vestrand, WT Wren, JA Wozniak, PR Aptekar, R Golentskii, S Pal'shin, V Sakamoto, T White, RR Evans, S Casperson, D Fenimore, E TI Energy input and response from prompt and early optical afterglow emission in gamma-ray bursts SO NATURE LA English DT Article ID RAPTOR OBSERVATIONS; TIME; GRB-050319 AB The taxonomy of optical emission detected during the critical first few minutes after the onset of a gamma-ray burst (GRB) defines two broad classes: prompt optical emission correlated with prompt gamma-ray emission(1), and early optical afterglow emission uncorrelated with the gamma-ray emission(2). The standard theoretical interpretation attributes prompt emission to internal shocks in the ultrarelativistic outflow generated by the internal engine(3-5); early afterglow emission is attributed to shocks generated by interaction with the surrounding medium(6-8). Here we report on observations of a bright GRB that, for the first time, clearly show the temporal relationship and relative strength of the two optical components. The observations indicate that early afterglow emission can be understood as reverberation of the energy input measured by prompt emission. Measurements of the early afterglow reverberations therefore probe the structure of the environment around the burst, whereas the subsequent response to late-time impulsive energy releases reveals how earlier flaring episodes have altered the jet and environment parameters. Many GRBs are generated by the death of massive stars that were born and died before the Universe was ten per cent of its current age(9,10), so GRB afterglow reverberations provide clues about the environments around some of the first stars. C1 Los Alamos Natl Lab, Space Sci & Applicat Grp, Los Alamos, NM 87545 USA. AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Vestrand, WT (reprint author), Los Alamos Natl Lab, Space Sci & Applicat Grp, ISR-1,MS-D466, Los Alamos, NM 87545 USA. EM vestrand@lanl.gov RI Pal'shin, Valentin/F-3973-2014; Aptekar, Raphail/B-3456-2015; OI Wozniak, Przemyslaw/0000-0002-9919-3310 NR 29 TC 87 Z9 88 U1 0 U2 2 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 13 PY 2006 VL 442 IS 7099 BP 172 EP 175 DI 10.1038/nature04913 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 062XJ UT WOS:000238979700040 PM 16838015 ER PT J AU Hansen, J AF Hansen, J TI The weather makers: How man is changing the climate and what it means for life on earth SO NEW YORK REVIEW OF BOOKS LA English DT Book Review C1 NASA, Goddard Inst Space Studies, Greenbelt, MD 20771 USA. Columbia Univ, Earth Inst, New York, NY 10027 USA. RP Hansen, J (reprint author), NASA, Goddard Inst Space Studies, Greenbelt, MD 20771 USA. NR 1 TC 13 Z9 14 U1 0 U2 3 PU NEW YORK REVIEW PI NEW YORK PA 250 WEST 57TH ST, NEW YORK, NY 10107 USA SN 0028-7504 J9 NEW YORK REV BOOKS JI N. Y. Rev. Books PD JUL 13 PY 2006 VL 53 IS 12 BP 12 EP + PG 4 WC Humanities, Multidisciplinary SC Arts & Humanities - Other Topics GA 055FQ UT WOS:000238435800005 ER PT J AU Krajewski, WF Anderson, MC Eichinger, WE Entekhabi, D Hornbuckle, BK Houser, PR Katul, GG Kustas, WP Norman, JM Peters-Lidard, C Wood, EF AF Krajewski, Witold F. Anderson, Martha C. Eichinger, William E. Entekhabi, Dara Hornbuckle, Brian K. Houser, Paul R. Katul, Gabriel G. Kustas, William P. Norman, John M. Peters-Lidard, Christa Wood, Eric F. TI A remote sensing observatory for hydrologic sciences: A genesis for scaling to continental hydrology SO WATER RESOURCES RESEARCH LA English DT Review ID LAND DATA ASSIMILATION; RAINDROP SIZE DISTRIBUTIONS; SOIL-MOISTURE VARIABILITY; SOUTHERN GREAT-PLAINS; SPATIAL VARIABILITY; BOUNDARY-LAYER; WATER-VAPOR; BRIGHTNESS TEMPERATURE; RAINFALL ESTIMATION; ENERGY FLUXES AB [ 1] Uncertainties in assessing the effects of global-scale perturbations on the climate system arise primarily from an inadequate understanding of the hydrological cycle: on land, in oceans, and in the atmosphere and biosphere. Because of this uncertainty, almost all science-based initiatives have expressed the need for continued advances in global observations and modeling of the Earth system. It is in this spirit that we advocate establishing a hydrologic remote sensing observatory (RSO) to advance sensing technologies and their use in scientific inquiry into hydrologic processes. There are two fundamental reasons why establishing such a RSO is timely. The first is operational: Developing assimilation techniques to estimate unobserved fluxes and uncertainties in hydrologic forecasts has sufficiently matured to take advantage of computing facilities and detailed hydrologic observations shaped by the RSO. The second is scientific: This RSO will permit us to refine knowledge from physical and hydrologic models that can then be converted to local and global strategies for water resources management and ecosystem health evaluation. The authors outline the conceptual design, scope, and functionality of a RSO and present four examples to illustrate how the hydrologic community can take advantage of such facility. C1 Univ Iowa, IIHR Hydrosci & Engn, Iowa City, IA 52242 USA. ARS, Hydrol & Remote Sensing Lab, USDA, Beltsville, MD 20705 USA. MIT, Dept Civil & Environm Engn, Cambridge, MA 02139 USA. Iowa State Univ, Dept Agron, Ames, IA 50011 USA. George Mason Univ, Ctr Res Environm & Water, Beltsville, MD 20705 USA. Duke Univ, Nicholas Sch Environm & Earth Sci, Durham, NC 27708 USA. Univ Wisconsin, Dept Soil Sci, Madison, WI 53706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 21042 USA. Princeton Univ, Dept Civil & Environm Engn, Princeton, NJ 08544 USA. RP Krajewski, WF (reprint author), Univ Iowa, IIHR Hydrosci & Engn, Iowa City, IA 52242 USA. EM witold-krajewski@uiowa.edu RI Katul, Gabriel/A-7210-2008; Peters-Lidard, Christa/E-1429-2012; Houser, Paul/J-9515-2013; Anderson, Martha/C-1720-2015 OI Katul, Gabriel/0000-0001-9768-3693; Peters-Lidard, Christa/0000-0003-1255-2876; Houser, Paul/0000-0002-2991-0441; Anderson, Martha/0000-0003-0748-5525 NR 102 TC 27 Z9 27 U1 3 U2 21 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 EI 1944-7973 J9 WATER RESOUR RES JI Water Resour. Res. PD JUL 13 PY 2006 VL 42 IS 7 AR W07301 DI 10.1029/2005WR004435 PG 13 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 066HZ UT WOS:000239221600001 ER PT J AU Strahan, SE Polansky, BC AF Strahan, S. E. Polansky, B. C. TI Meteorological implementation issues in chemistry and transport models SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID HALOGEN OCCULTATION EXPERIMENT; SEMI-LAGRANGIAN TRANSPORT; TRACER TRANSPORT; CLIMATE MODEL; STRATOSPHERIC TRANSPORT; INITIATIVE ASSESSMENT; NUMERICAL ADVECTION; POLAR VORTEX; OZONE; SIMULATIONS AB Offline chemistry and transport models (CTMs) are versatile tools for studying composition and climate issues requiring multi-decadal simulations. They are computationally fast compared to coupled chemistry climate models, making them well-suited for integrating sensitivity experiments necessary for understanding model performance and interpreting results. The archived meteorological fields used by CTMs can be implemented with lower horizontal or vertical resolution than the original meteorological fields in order to shorten integration time, but the effects of these shortcuts on transport processes must be understood if the CTM is to have credibility. In this paper we present a series of sensitivity experiments on a CTM using the Lin and Rood advection scheme, each differing from another by a single feature of the wind field implementation. Transport effects arising from changes in resolution and model lid height are evaluated using process-oriented diagnostics that intercompare CH4, O-3, and age tracer carried in the simulations. Some of the diagnostics used are derived from observations and are shown as a reality check for the model. Processes evaluated include tropical ascent, tropical-midlatitude exchange, poleward circulation in the upper stratosphere, and the development of the Antarctic vortex. We find that faithful representation of stratospheric transport in this CTM is possible with a full mesosphere, similar to 1 km resolution in the lower stratosphere, and relatively low vertical resolution (> 4 km spacing) in the middle stratosphere and above, but lowering the lid from the upper to lower mesosphere leads to less realistic constituent distributions in the upper stratosphere. Ultimately, this affects the polar lower stratosphere, but the effects are greater for the Antarctic than the Arctic. The fidelity of lower stratospheric transport requires realistic tropical and high latitude mixing barriers which are produced at 2 degrees x 2.5 degrees, but not lower resolution. At 2 degrees x 2.5 degrees resolution, the CTM produces a vortex capable of isolating perturbed chemistry ( e. g. high Cl-y and low NOy) required for simulating polar ozone loss. C1 Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP Strahan, SE (reprint author), Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, 5523 Res Pk Dr,Suite 320, Baltimore, MD 21228 USA. EM sstrahan@pop600.gsfc.nasa.gov RI Strahan, Susan/H-1965-2012 NR 33 TC 17 Z9 17 U1 0 U2 2 PU EUROPEAN GEOSCIENCES UNION PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 1680-7316 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JUL 12 PY 2006 VL 6 BP 2895 EP 2910 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 062ZP UT WOS:000238985900004 ER PT J AU Zhou, B Lin, Y Hill, DE Wang, W Veca, LM Qu, LW Pathak, P Meziani, MJ Diaz, J Connell, JW Watson, KA Allard, LF Sun, YP AF Zhou, Bing Lin, Yi Hill, Darron E. Wang, Wei Veca, L. Monica Qu, Liangwei Pathak, Pankaj Meziani, Mohammed J. Diaz, Julian Connell, John W. Watson, Kent A. Allard, Lawrence F. Sun, Ya-Ping TI Polymeric nanocomposite films from functionalized vs suspended single-walled carbon nanotubes SO POLYMER LA English DT Article DE carbon nanotubes; nanocomposites; photoluminescence ID DISPERSION; LUMINESCENCE; COMPOSITES; SPECTROSCOPY; PURIFICATION; POLYIMIDE; CHEMISTRY AB The reported work was to demonstrate that the defect-derived photoluminescence in functionalized single-walled carbon nanotubes could be exploited in probing the dispersion of these nanotubes in polymeric nanocomposites because the luminescence emissions are sensitive to the degree of nanotube bundling and surface modification. The polyimide-SWNT nanocomposite thin films obtained from nanotubes with and without functionalization were compared. The spectroscopic results suggest that despite a similar visual appearance in the two kinds of films, the nanotube dispersion must be significantly better in the film with functionalized nanotubes, as reflected by the strong photoluminescence. In fact, the nanotubes embedded in polymer matrix that can be readily characterized by Raman spectroscopy are non-luminescent, while those that are difficult for Raman are strongly luminescent. Therefore, Raman and photoluminescence serve as complementary tools in the investigation of nanocomposites concerning the nanotube dispersion-related properties. (c) 2006 Elsevier Ltd. All rights reserved. C1 Clemson Univ, Dept Chem, Clemson, SC 29634 USA. Clemson Univ, Lab Emerging Mat & Technol, Clemson, SC 29634 USA. NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. Natl Inst Aerosp, Hampton, VA 23666 USA. Oak Ridge Natl Lab, High Temp Mat Lab, Oak Ridge, TN 37831 USA. RP Sun, YP (reprint author), Clemson Univ, Dept Chem, Clemson, SC 29634 USA. EM syaping@clemson.edu RI Veca, Lucia/A-4622-2012 NR 30 TC 23 Z9 23 U1 0 U2 15 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0032-3861 J9 POLYMER JI Polymer PD JUL 12 PY 2006 VL 47 IS 15 BP 5323 EP 5329 DI 10.1016/j.polymer.2006.05.055 PG 7 WC Polymer Science SC Polymer Science GA 072AC UT WOS:000239644000014 ER PT J AU Zhang, YC Rossow, WB Stackhouse, PW AF Zhang, Yuanchong Rossow, William B. Stackhouse, Paul W., Jr. TI Comparison of different global information sources used in surface radiative flux calculation: Radiative properties of the near-surface atmosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ISCCP DATA SETS; DATASET; TOVS; TOP AB [1] Direct estimates of surface radiative fluxes that resolve regional and weather-scale variability over the whole globe with reasonable accuracy have only become possible with the advent of extensive global, mostly satellite, data sets within the past couple of decades. The accuracy of these fluxes, estimated to be about 10 - 15 W/m(2), is largely limited by the uncertainties of the input data sets. This study presents a fuller, more quantitative evaluation of these uncertainties, mainly for the near-surface air temperature and humidity, by comparing the main available global data sets from the European Centre for Medium-Range Weather Forecasts, NASA, the National Centers for Environmental Prediction, the International Satellite Cloud Climatology Project (ISCCP) and the Laboratoire de Meteorologie Dynamique that are treated as ensemble realizations of actual climate such that their differences represent an estimate of the uncertainty in their measurements ( because we do not know the absolute truth). The results are globally representative and may be taken as a generalization of our previous ISCCP-based uncertainty estimates for the input data sets. Near-surface atmospheric properties have the primary role in determining the surface downward longwave ( LW) flux. From this study, the most important quantity, the surface air temperature, has a uncertainty of about 2 - 4 K ( 3 K on average), which would easily induce about 15 W/m(2) uncertainty for surface downward LW flux. The humidity profile comparison suggests an uncertainty of 20 - 25% for the atmospheric column precipitable water below the 300 hPa level, which would cause less than or similar to 10 W/m(2) uncertainty for surface downward LW flux, making it the second largest source of uncertainty. The comparison for the difference between surface skin and air temperature shows its uncertainty is about 2 - 3 K, which translates into 10 - 15 W/m(2) uncertainty for surface net LW flux. The used atmospheric data set from ISCCP represents the diurnal variations better than the other available sources ( as it was designed to do) and the synoptic variations only slightly better than the other sources, but it still has notable clear-cloudy sky biases and interannual variations that are dominated by spurious changes introduced by methodology changes in the original TOVS product. In a companion paper, the work is extended to evaluate the uncertainties of surface radiative properties. C1 Columbia Univ, NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Zhang, YC (reprint author), Columbia Univ, NASA, Goddard Inst Space Studies, New York, NY 10025 USA. EM yzhang@giss.nasa.gov RI Rossow, William/F-3138-2015 NR 24 TC 44 Z9 44 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 JUL 11 PY 2006 VL 111 IS D13 AR D13106 DI 10.1029/2005JD006873 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 066GA UT WOS:000239216500001 ER PT J AU Lew, JS Horta, LG Reaves, MC AF Lew, JS Horta, LG Reaves, MC TI Uncertainty quantification of an inflatable/rigidizable torus SO JOURNAL OF SOUND AND VIBRATION LA English DT Article AB There is an increasing interest in lightweight inflatable structures for space missions. The dynamic testing and model updating of these types of structures present many challenges in terms of model uncertainty and structural nonlinearity. This paper presents an experimental study of uncertainty quantification of a 3m-diameter inflatable torus. Model uncertainty can be thought of as coming from two different sources, uncertainty due to changes in controlled conditions, such as temperature and input force level, and uncertainty associated with others random factors, such as measurement noise, etc. To precisely investigate and quantify model uncertainty from different sources, experiments, using sine-sweep excitation in the specified narrow frequency bands, are conducted to collect frequency response function (FRF) under various test conditions. To model the variation of the identified parameters, a singular value decomposition technique is applied to extract the principal components of the parameter change. (c) 2006 Elsevier Ltd. All rights reserved. C1 Tennessee State Univ, Nashville, TN 37209 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Lew, JS (reprint author), Tennessee State Univ, Nashville, TN 37209 USA. EM lew@coe.tsuniv.edu NR 8 TC 2 Z9 4 U1 1 U2 3 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD JUL 11 PY 2006 VL 294 IS 3 BP 615 EP 623 DI 10.1016/j.jsv.2005.11.029 PG 9 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 051FH UT WOS:000238146500015 ER PT J AU Panaitescu, A Meszaros, P Burrows, D Nousek, J Gehrels, N O'Brien, P Willingale, R AF Panaitescu, A Meszaros, P Burrows, D Nousek, J Gehrels, N O'Brien, P Willingale, R TI Evidence for chromatic X-ray light-curve breaks in Swift gamma-ray burst afterglows and their theoretical implications SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE radiation mechanisms : non-thermal; shock waves; ISM : jets and outflows; gamma-rays : bursts ID GRB-050401; GRB-030329; ENERGY; DECAY; JETS AB The power-law decay of the X-ray emission of gamma-ray burst (GRB) afterglows 050319, 050401, 050607, 050713A, 050802 and 050922C exhibits a steepening at about 1-4 h after the burst which, surprisingly, is not accompanied by a break in the optical emission. If it is assumed that both the optical and X-ray afterglows arise from the same outflow then, in the framework of the standard forward shock model, the chromaticity of the X-ray light-curve breaks indicates that they do not arise solely from a mechanism related to the outflow dynamics (e.g. energy injection) or the angular distribution of the blast-wave kinetic energy (structured outflows or jets). The lack of a spectral evolution accompanying the X-ray light-curve break shows that these breaks do not arise from the passage of a spectral break (e.g. the cooling frequency) either. Under these circumstances, the decoupling of the X-ray and optical decays requires that the microphysical parameters for the electron and magnetic energies in the forward shock evolve in time, whether the X-ray afterglow is synchrotron or inverse-Compton emission. For a steady evolution of these parameters with the Lorentz factor of the forward shock and an X-ray light curve arising cessation of energy injection into the blast wave, the optical and X-ray properties of the above six Swift afterglows require a circumburst medium with a r(-2) radial stratification, as expected for a massive star origin for long GRBs. Alternatively, the chromatic X-ray light-curve breaks may indicate that the optical and X-ray emissions arise from different outflows. Neither feature (evolution of microphysical parameters or the different origin of the optical and X-ray emissions) was clearly required by pre-Swift afterglows. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. RP Panaitescu, A (reprint author), Los Alamos Natl Lab, Los Alamos, NM 87545 USA. EM alin@lanl.gov RI Gehrels, Neil/D-2971-2012 NR 30 TC 159 Z9 161 U1 0 U2 2 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 JUL 11 PY 2006 VL 369 IS 4 BP 2059 EP 2064 DI 10.1111/j.1365-2966.2006.10453.x PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 057VZ UT WOS:000238624600054 ER PT J AU Feikema, DA AF Feikema, Douglas A. TI Quantitative rainbow schlieren deflectometry as a temperature diagnostic for nonsooting spherical flames SO APPLIED OPTICS LA English DT Article ID DIFFUSION FLAMES AB Numerical analysis and experimental results are presented to define a method for quantitatively measuring the temperature distribution of a spherical diffusion flame using rainbow schlieren deflectometry in Microgravity. The method employed illustrates the necessary steps for the preliminary design of a rainbow schlieren system. The largest deflection for the normal gravity flame considered in this paper is 7.4 X 10(-4) rad, which can be accurately measured with 2 m focal-length collimating and decollimating optics. The experimental uncertainty of deflection is less than 5 X 10(-5) rad. (C) 2006 Optical Society of America. C1 NASA, Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP Feikema, DA (reprint author), NASA, Glenn Res Ctr Lewis Field, 21000 Brookpark Rd, Cleveland, OH 44135 USA. EM douglas.feikema@grc.nasa.gov NR 24 TC 8 Z9 9 U1 1 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUL 10 PY 2006 VL 45 IS 20 BP 4826 EP 4832 DI 10.1364/AO.45.004826 PG 7 WC Optics SC Optics GA 063KV UT WOS:000239018000005 PM 16807588 ER PT J AU Koswatta, SO Hasan, S Lundstrom, MS Anantram, MP Nikonov, DE AF Koswatta, Siyuranga O. Hasan, Sayed Lundstrom, Mark S. Anantram, M. P. Nikonov, Dmitri E. TI Ballisticity of nanotube field-effect transistors: Role of phonon energy and gate bias SO APPLIED PHYSICS LETTERS LA English DT Article ID CARBON NANOTUBES; SCATTERING; TRANSPORT AB We investigate the role of electron-phonon scattering and gate bias in degrading the drive current of nanotube field-effect transistors (FETs). Optical phonon scattering significantly decreases the drive cur-rent only when gate voltage is higher than a well-defined. threshold. For comparable electron-phonon coupling, a lower phonoh energy leads to a larger degradation of drive current. Thus in semiconductor nanowire FETs, the drive current will be more sensitive than in carbon nanotube FETs because of the smaller phonon energies in semiconductors. Acoustic phonons and other elastic scattering mechanisms are most detrimental to nanotube FETs irrespective of biasing conditions. (c) 2006 American Institute of Physics. C1 Purdue Univ, Sch Elect & Comp Engn, W Lafayette, IN 47907 USA. NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. Intel Corp, Technol & Mfg Grp, Santa Clara, CA 95052 USA. RP Koswatta, SO (reprint author), Purdue Univ, Sch Elect & Comp Engn, W Lafayette, IN 47907 USA. EM dmitri.e.nikonov@intel.com RI Nikonov, Dmitri/B-6502-2011 OI Nikonov, Dmitri/0000-0002-1436-1267 NR 24 TC 42 Z9 42 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 10 PY 2006 VL 89 IS 2 AR 023125 DI 10.1063/1.2218322 PG 3 WC Physics, Applied SC Physics GA 074DO UT WOS:000239793100106 ER PT J AU Phillips, NG Kogut, A AF Phillips, N. G. Kogut, A. TI Constraints on the topology of the universe from the Wilkinson microwave anisotropy probe first-year sky maps SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations ID WMAP OBSERVATIONS; BACKGROUND-RADIATION AB We compute the covariance expected between the spherical harmonic coefficients a(lm) of the cosmic microwave temperature anisotropy if the universe had a compact topology. For a fundamental cell size smaller than the distance to the decoupling surface, off-diagonal components carry more information than the diagonal components (the power spectrum). We use a maximum likelihood analysis to compare the Wilkinson Microwave Anisotropy Probe (WMAP) first-year data to models with a cubic topology. The data are compatible with finite flat topologies with fundamental domain L > 1.2 times the distance to the decoupling surface at a 95% confidence level. The WMAP data show reduced power at the quadrupole and octopole, but they do not show the correlations expected for a compact topology and are indistinguishable from infinite models. C1 NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. RP Phillips, NG (reprint author), NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. EM nicholas.g.phillips.1@gsfc.nasa.gov RI Kogut, Alan/D-6293-2012 NR 17 TC 16 Z9 16 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 JUL 10 PY 2006 VL 645 IS 2 BP 820 EP 825 DI 10.1086/432861 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 063XT UT WOS:000239053900004 ER PT J AU Quillen, AC Brookes, MH Keene, J Stern, D Lawrence, CR Werner, MW AF Quillen, Alice C. Brookes, Mairi H. Keene, Jocelyn Stern, Daniel Lawrence, Charles R. Werner, Michael W. TI Spitzer observations of the dusty warped disk of Centaurus A SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 5128); galaxies : ISM; galaxies : peculiar; galaxies : structure ID SUPERMASSIVE BLACK-HOLE; SPACE-TELESCOPE; POLAR RINGS; NGC-5128; GALAXY; GAS; KINEMATICS; EMISSION; DYNAMICS; NUCLEUS AB Spitzer mid-infrared images of the dusty warped disk in the galaxy Centaurus A show a parallelogram-shaped structure. We successfully model the observed mid-infrared morphology by integrating the light from an emitting, thin, and warped disk, similar to that inferred from previous kinematic studies. The models with the best match to the morphology lack dust emission within the inner 0.1-0.8 kpc, suggesting that energetic processes near the nucleus have disturbed the inner molecular disk, creating a gap in the molecular gas distribution. C1 Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Quillen, AC (reprint author), Univ Rochester, Dept Phys & Astron, 601 Elmwood Ave, Rochester, NY 14627 USA. EM aquillen@pas.rochester.edu; Mairi.H.Brookes@jpl.nasa.gov; jkeene@caltech.edu; stern@zwolfkinder.jpl.nasa.gov; charles.lawrence@jpl.nasa.gov; Michael.W.Werner@jpl.nasa.gov NR 39 TC 36 Z9 36 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 JUL 10 PY 2006 VL 645 IS 2 BP 1092 EP 1101 DI 10.1086/504418 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 063XT UT WOS:000239053900028 ER PT J AU Jorgensen, JK Harvey, PM Evans, NJ Huard, TL Allen, LE Porras, A Blake, GA Bourke, TL Chapman, N Cieza, L Koerner, DW Lai, SP Mundy, LG Myers, PC Padgett, DL Rebull, L Sargent, AI Spiesman, W Stapelfeldt, KR van Dishoeck, EF Wahhaj, Z Young, KE AF Jorgensen, Jes K. Harvey, Paul M. Evans, Neal J., II Huard, Tracy L. Allen, Lori E. Porras, Alicia Blake, Geoffrey A. Bourke, Tyler L. Chapman, Nicholas Cieza, Lucas Koerner, David W. Lai, Shih-Ping Mundy, Lee G. Myers, Philip C. Padgett, Deborah L. Rebull, Luisa Sargent, Anneila I. Spiesman, William Stapelfeldt, Karl R. van Dishoeck, Ewine F. Wahhaj, Zahed Young, Kaisa E. TI The Spitzer c2d survey of large, nearby, interstellar clouds. III. Perseus observed with IRAC SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; ISM : clouds; stars : formation ID YOUNG STELLAR OBJECTS; MOLECULAR CLOUD; STAR-FORMATION; CLUSTER IC-348; OPHIUCHI CLOUD; DARK CLOUD; PROTOSTARS; EXTINCTION; OUTFLOWS; NGC-1333 AB We present observations of 3.86 deg(2) of the Perseus molecular cloud complex with the Spitzer Space Telescope Infrared Array Camera (IRAC). The maps show strong extended emission arising from shocked H-2 in outflows and from polycyclic aromatic hydrocarbon features. More than 120,000 sources are extracted toward the cloud. Based on their IRAC colors and comparison to off-cloud and extragalactic fields, we identify 400 candidate young stellar objects. About two-thirds of these are associated with the young clusters IC 348 and NGC 1333, while the last third is distributed over the remaining cloud. The young stellar objects are classified according to the slope of their spectral energy distributions. Significant differences are found between the numbers of embedded Class I objects and more evolved Class II objects in IC 348, NGC 1333 and the remaining cloud, with the embedded Class I and "flatspectrum'' YSOs constituting 14%, 36% and 47% of the total number of YSOs identified in each of these regions. The high number of Class I objects in the extended cloud (61% of the Class I objects in the entire cloud) suggests that a significant fraction of the current star formation occurs outside the two main clusters. Finally, we discuss a number of outflows and identify their driving sources, including the deeply embedded Class 0 sources outside the two main clusters. The Class 0 objects are detected by Spitzer and have very red [3.6] - [4.5] colors, but they do not show similarly red [5.8] - [8.0] colors. The Class 0 objects are easily identifiable in color-color diagrams but are problematic to extract automatically due to the extended emission from shocked gas or scattered light in cavities related to the associated outflows. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. No Arizona Univ, Dept Phys & Astron, Flagstaff, AZ 86011 USA. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. Leiden Observ, NL-2300 RA Leiden, Netherlands. RP Jorgensen, JK (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS42, Cambridge, MA 02138 USA. EM jjorgensen@cfa.harvard.edu RI Stapelfeldt, Karl/D-2721-2012; OI Rebull, Luisa/0000-0001-6381-515X NR 47 TC 159 Z9 159 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 JUL 10 PY 2006 VL 645 IS 2 BP 1246 EP 1263 DI 10.1086/504373 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 063XT UT WOS:000239053900041 ER PT J AU Padgett, DL Cieza, L Stapelfeldt, KR Evans, NJ Koerner, D Sargent, A Fukagawa, M van Dishoeck, EF Augereau, JC Allen, L Blake, G Brooke, T Chapman, N Harvey, P Porras, A Lai, SP Mundy, L Myers, PC Spiesman, W Wahhaj, Z AF Padgett, Deborah L. Cieza, Lucas Stapelfeldt, Karl R. Evans, Neal J., II Koerner, David Sargent, Anneila Fukagawa, Misato van Dishoeck, Ewine F. Augereau, Jean-Charles Allen, Lori Blake, Geoff Brooke, Tim Chapman, Nicholas Harvey, Paul Porras, Alicia Lai, Shih-Ping Mundy, Lee Myers, Philip C. Spiesman, William Wahhaj, Zahed TI The Spitzer c2d survey of weak-line T Tauri stars. I. Initial results SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; planetary systems : protoplanetary disks; stars : pre-main-sequence ID MAIN-SEQUENCE STARS; SPECTRAL ENERGY-DISTRIBUTIONS; YOUNG STELLAR OBJECTS; X-RAY SOURCES; SPACE-TELESCOPE; PROPER MOTION; PROTOPLANETARY DISKS; CIRCUMSTELLAR DISKS; EVOLUTIONARY STATUS; PLANET FORMATION AB Using the Spitzer Space Telescope, we have observed 90 weak-line and classical T Tauri stars in the vicinity of the Ophiuchus, Lupus, Chamaeleon, and Taurus star-forming regions as part of the Cores to Disks (c2d) Spitzer Legacy project. In addition to the Spitzer data, we have obtained contemporaneous optical photometry to assist in constructing spectral energy distributions. These objects were specifically chosen as solar-type young stars with low levels of H alpha emission, strong X-ray emission, and lithium absorption, i.e., weak-line T Tauri stars, most of which were undetected in the mid- to far-IR by the IRAS survey. Weak-line T Tauri stars are potentially extremely important objects in determining the timescale over which disk evolution may take place. Our objective is to determine whether these young stars are diskless or have remnant disks that are below the detection threshold of previous infrared missions. We find that only 5/83 weak-line T Tauri stars have detectable excess emission between 3.6 and 70 mu m, which would indicate the presence of dust from the inner few tenths of an AU out to the planet-forming regions a few tens of AU from the star. Of these sources, two have small excesses at 24 mu m consistent with optically thin disks; the others have optically thick disks already detected by previous IR surveys. All of the seven classical T Tauri stars show excess emission at 24 and 70 mu m although their properties vary at shorter wavelengths. Our initial results show that disks are rare among young stars selected for their weak H alpha emission. C1 CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. Jet Propuls Lab, Pasadena, CA 91109 USA. No Arizona Univ, Dept Phys & Astron, Flagstaff, AZ 86011 USA. CALTECH, Pasadena, CA 91125 USA. Leiden Observ, NL-2300 RA Leiden, Netherlands. Harvard Smithsonian Ctr Astrophys, Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Padgett, DL (reprint author), CALTECH, Spitzer Sci Ctr, Mail Code 220-6, Pasadena, CA 91125 USA. EM dlp@ipac.caltech.edu RI Stapelfeldt, Karl/D-2721-2012 NR 88 TC 60 Z9 61 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 JUL 10 PY 2006 VL 645 IS 2 BP 1283 EP 1296 DI 10.1086/504374 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 063XT UT WOS:000239053900044 ER PT J AU Pagani, C Morris, DC Kobayashi, S Sakamoto, T Falcone, AD Moretti, A Page, K Burrows, DN Grupe, D Retter, A Racusin, J Kennea, JA Campana, S Romano, P Tagliaferri, G Hill, JE Angelini, L Cusumano, G Goad, MR Barthelmy, S Chincarini, G Wells, A Giommi, P Nousek, JA Gehrels, N AF Pagani, Claudio Morris, David C. Kobayashi, Shiho Sakamoto, Takanori Falcone, Abraham D. Moretti, Alberto Page, Kim Burrows, David N. Grupe, Dirk Retter, Alon Racusin, Judith Kennea, Jamie A. Campana, Sergio Romano, Patrizia Tagliaferri, Gianpiero Hill, Joanne E. Angelini, Lorella Cusumano, Giancarlo Goad, Michael R. Barthelmy, Scott Chincarini, Guido Wells, Alan Giommi, Paolo Nousek, John A. Gehrels, Neil TI The Swift X-ray flaring afterglow of GRB 050607 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; X-rays : individual (GRB 050607) ID BURST AFTERGLOWS; ENGINE ACTIVITY; TELESCOPE; EMISSION; INJECTION; CATALOG; MISSION AB The unique capability of the Swift satellite to perform a prompt and autonomous slew to a newly detected gamma-ray burst (GRB) has yielded the discovery of interesting new properties of GRB X-ray afterglows, such as the steep early light-curve decay and the frequent presence of flares detected up to a few hours after the GRB trigger. We present observations of GRB 050607, the fourth case of a GRB discovered by Swift with flares superimposed on the overall fading X-ray afterglow. The flares of GRB 050607 were not symmetric as in previously reported cases, showing a very steep rise and a shallower decay, similar to the fast rise, exponential decay that are frequently observed in the gamma-ray prompt emission. The brighter flare had a flux increase by a factor of similar to 25, peaking for 30 s at a count rate of approximately 30 counts s(-1), and it presented hints of additional short-timescale activity during the decay phase. There is evidence of spectral evolution during the flares. In particular, at the onset of the flares the observed emission was harder, with a gradual softening as each flare decayed. The very short timescale and the spectral variability during the flaring activity are indicators of possible extended periods of energy emission by the GRB central engine. The flares were followed by a phase of shallow decay, during which the forward shock was being refreshed by a long-lived central engine or by shells of lower Lorentz factors, and by a steepening after approximately 12 ks to a decay slope considered typical of X-ray afterglows. C1 INAF, Osservat Astron Brera, I-23807 Merate, Italy. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Liverpool John Moores Univ, Astrophys Res Inst, Birkenhead CH41 1LD, Merseyside, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Univ Space Res Assoc, Columbia, MD 21044 USA. INAF, Ist Astrofis Spaziale & Fis Cosm, Sez Palermo, I-90146 Palermo, Italy. Univ Leicester, Space Res Ctr, Leicester LE1 7RH, Leics, England. ASI Sci Data Ctr, I-00044 Frascati, Italy. RP Pagani, C (reprint author), INAF, Osservat Astron Brera, Via Bianchi 46, I-23807 Merate, Italy. EM pagani@astro.psu.edu RI Racusin, Judith/D-2935-2012; Barthelmy, Scott/D-2943-2012; Gehrels, Neil/D-2971-2012; OI Campana, Sergio/0000-0001-6278-1576; giommi, paolo/0000-0002-2265-5003; Cusumano, Giancarlo/0000-0002-8151-1990; Tagliaferri, Gianpiero/0000-0003-0121-0723 NR 40 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 JUL 10 PY 2006 VL 645 IS 2 BP 1315 EP 1322 DI 10.1086/504518 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 063XT UT WOS:000239053900047 ER PT J AU Badenes, C Borkowski, KJ Hughes, JP Hwang, U Bravo, E AF Badenes, Carles Borkowski, Kazimierz J. Hughes, John P. Hwang, Una Bravo, Eduardo TI Constraints on the physics of type Ia supernovae from the X-ray spectrum of the Tycho supernova remnant SO ASTROPHYSICAL JOURNAL LA English DT Article DE hydrodynamics; ISM : individual (SN 1572); nuclear reactions, nucleosynthesis, abundances; supernova remnants; supernovae : general; X-rays : ISM ID EFFICIENT PARTICLE-ACCELERATION; DELAYED-DETONATION MODEL; XMM-NEWTON OBSERVATION; LIGHT CURVES; EXPLOSION MODELS; INFRARED-SPECTRA; REVERSE SHOCKS; LINE EMISSION; EXPANSION; EJECTA AB In this paper we use high-quality X-ray observations from XMM-Newton and Chandra to gain new insights into the explosion that originated Tycho's supernova 433 yr ago. We perform a detailed comparison between the ejecta emission from the spatially integrated X-ray spectrum of the supernova remnant and current models for Type Ia supernova explosions. We use a grid of synthetic X-ray spectra based on hydrodynamic models of the evolution of the supernova remnant and nonequilibrium ionization calculations for the state of the shocked plasma. We find that the fundamental properties of the X-ray emission in Tycho are well reproduced by a one-dimensional delayed detonation model with a kinetic energy of similar to 1.2 x 10(51) ergs. All the other paradigms for Type Ia explosions that we have tested, including one-dimensional deflagrations, pulsating delayed detonations, and sub-Chandrasekhar explosions, as well as deflagration models calculated in three dimensions, fail to provide a good approximation of the observed ejecta emission. Our results require that the supernova ejecta retain some degree of chemical stratification, with Fe peak elements interior to intermediate-mass elements. This strongly suggests that a supersonic burning front (i.e., a detonation) must be involved at some stage in the physics of Type Ia supernova explosions. C1 Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. N Carolina State Univ, Dept Phys, Raleigh, NC 27695 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Politecn Cataluna, Dept Fis & Engn Nucl, E-08028 Barcelona, Spain. Inst Estudis Espacials Catalunya, Fac Ciencies, Barcelona 08193, Spain. RP Badenes, C (reprint author), Rutgers State Univ, Dept Phys & Astron, 136 Frelinghuysen Rd, Piscataway, NJ 08854 USA. EM badenes@physics.rutgers.edu; kborkow@unity.ncsu.edu; jph@physics.rutgers.edu; hwang@orfeo.gsfc.nasa.gov; eduardo.bravo@upc.es RI Bravo, Eduardo/B-1790-2008; OI Bravo, Eduardo/0000-0003-0894-6450; Badenes, Carles/0000-0003-3494-343X NR 73 TC 124 Z9 124 U1 0 U2 5 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 JUL 10 PY 2006 VL 645 IS 2 BP 1373 EP 1391 DI 10.1086/504399 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 063XT UT WOS:000239053900052 ER PT J AU Marion, GH Hoflich, P Wheeler, JC Robinson, EL Gerardy, CL Vacca, WD AF Marion, G. H. Hoflich, P. Wheeler, J. C. Robinson, E. L. Gerardy, C. L. Vacca, W. D. TI Low carbon abundance in type Ia supernovae SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; line : formation; line : identification; supernovae : general ID HIGH-VELOCITY FEATURES; NEAR-INFRARED SPECTRA; EXPLOSION MODELS; CIRCUMSTELLAR INTERACTION; LIGHT CURVES; WHITE-DWARFS; SN 1994D; PROGENITORS; SIMULATIONS; DETONATION AB We investigate the quantity and composition of unburned material in the outer layers of three normal Type Ia supernovae (SNe Ia): 2000dn, 2002cr, and 2004bw. Pristine matter from a white dwarf progenitor is expected to be a mixture of oxygen and carbon in approximately equal abundance. Using near-infrared (NIR, 0.7-2.5 mu m) spectra, we find that oxygen is abundant, while carbon is severely depleted with low upper limits in the outer third of the ejected mass. Strong features from the OI line at lambda(rest) 0: 7773 mu m are observed through awide range of expansion velocities approximate to (9-18) x 10(3) km s(-1). This large velocity domain corresponds to a physical region of the supernova with a large radial depth. We show that the ionization of C and O will be substantially the same in this region. C I lines in the NIR are expected to be 7 - 50 times stronger than those from O I, but there is only marginal evidence of C I in the spectra and none of C II. We deduce that for these three normal SNe Ia, oxygen is more abundant than carbon by factors of 10(2)-10(3). Mg II is also detected in a velocity range similar to that of O I. The presence of O and Mg combined with the absence of C indicates that for these SNe Ia, nuclear burning has reached all but the extreme outer layers; any unburned material must have expansion velocities greater than 18 x 10(3) km s(-1). This result favors deflagration to detonation transition (DD) models over pure deflagration models for SNe Ia. C1 Univ Texas, Dept Astron, Austin, TX 78712 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, London SW7 2AZ, England. NASA, Ames Res Ctr, SOFIA USRA, Moffett Field, CA 94035 USA. RP Marion, GH (reprint author), Univ Texas, Dept Astron, Austin, TX 78712 USA. NR 44 TC 35 Z9 35 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 JUL 10 PY 2006 VL 645 IS 2 BP 1392 EP 1401 DI 10.1086/502712 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 063XT UT WOS:000239053900053 ER PT J AU Kucera, TA Landi, E AF Kucera, T. A. Landi, E. TI Ultraviolet observations of prominence activation and cool loop dynamics SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : atmospheric motions; Sun : corona; Sun : prominences; Sun : transition region; Sun : UV radiation ID DIAGNOSTIC SPECTROMETER CDS; SOLAR CORONAL LOOPS; ACTIVE-REGION LOOPS; OPTICALLY THIN PLASMAS; TRANSITION-REGION; THERMAL NONEQUILIBRIUM; ALPHA OBSERVATIONS; MAGNETIC-FIELDS; FLOWS; FILAMENT AB In this paper we investigate the thermal and dynamic properties of dynamic structures in and around a prominence channel observed on the limb on 2003 April 17. Observations were taken with the Solar and Heliospheric Observatory's Solar Ultraviolet Measurements of Emitted Radiation (SOHO SUMER) in lines formed at temperatures from 80,000 K to 1.6 MK. The instrument was pointed to a single location and took a series of 90 s exposures. Two-dimensional context was provided by the Transition Region and Coronal Explorer (TRACE) in the UV and EUV and the Kanzelhohe Solar Observatory in H alpha. Two dynamic features were studied in depth: an activated prominence and repeated motions in a loop near the prominence. We calculated three-dimensional geometries and trajectories, differential emission measures, and limits on the mass, pressure, average density, and kinetic and thermal energies. These observations provide important tests for models of dynamics in prominences and cool (similar to 10(5) K) loops, which will ultimately lead to a better understanding of the mechanism(s) leading to energy and mass flow in these solar features. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USN, Res Lab, Washington, DC 20375 USA. Artep Inc, Annapolis, MD 21402 USA. RP Kucera, TA (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM therese.a.kucera@nasa.gov RI Landi, Enrico/H-4493-2011; Kucera, Therese/C-9558-2012; OI Kucera, Therese/0000-0001-9632-447X NR 43 TC 13 Z9 13 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 JUL 10 PY 2006 VL 645 IS 2 BP 1525 EP 1536 DI 10.1086/504398 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 063XT UT WOS:000239053900064 ER PT J AU Danchi, WC Rajagopal, J Kuchner, M Richardson, LJ Deming, D AF Danchi, W. C. Rajagopal, J. Kuchner, M. Richardson, L. J. Deming, D. TI The importance of phase in nulling interferometry and a three-telescope closure-phase nulling interferometer concept SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; planetary systems; techniques : high angular resolution; techniques : interferometric; telescopes ID KELVIN-STELLAR-INTERFEROMETER; EXTRASOLAR GIANT PLANETS; NON-SOLAR PLANETS; SELF-CALIBRATION; SEARCH AB We discuss the theory of the Bracewell nulling interferometer and explicitly demonstrate that the phase of the ''white light'' null fringe is the same as the phase of the bright output from an ordinary stellar interferometer. As a consequence, a ''closure phase'' exists for a nulling interferometer with three or more telescopes. We calculate the phase offset as a function of baseline length for an Earth-like planet around the Sun at 10 pc, with a contrast ratio of 10(-6) at 10 mu m. The magnitude of the phase due to the planet is similar to 10(-6) radians, assuming the star is at the phase center of the array. Although this is small, this phase may be observable in a three-telescope nulling interferometer that measures the closure phase. We propose a simple nonredundant three-telescope nulling interferometer that can perform this measurement. This configuration is expected to have improved characteristics compared to other nulling interferometer configurations, such as a relaxation of path length tolerances, through the use of the ''ratio of wavelengths'' technique, a closure phase, and better discrimination between extrasolar zodiacal dust and planets. C1 NASA, Goddard Space Flight Ctr, Exoplanets & Stellar Astrophys Lab, Greenbelt, MD 20771 USA. RP Danchi, WC (reprint author), NASA, Goddard Space Flight Ctr, Exoplanets & Stellar Astrophys Lab, Code 661, Greenbelt, MD 20771 USA. EM William.C.Danchi@nasa.gov RI Kuchner, Marc/E-2288-2012 NR 21 TC 4 Z9 4 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 JUL 10 PY 2006 VL 645 IS 2 BP 1554 EP 1559 DI 10.1086/504511 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 063XT UT WOS:000239053900067 ER PT J AU Lovas, FJ Hollis, JM Remijan, AJ Jewell, PR AF Lovas, F. J. Hollis, J. M. Remijan, Anthony J. Jewell, P. R. TI Detection of ketenimine (CH2CNH) in Sagittarius B2(N) hot cores SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : abundances; ISM : clouds; ISM : individual (Sagittarius B2(N-LMH)); ISM : molecules; radio lines : ISM ID ACETONITRILE; ION; ARGON; TMC-1 AB Ketenimine (CH2CNH) has been detected in absorption toward the star-forming region Sagittarius B2(N) with the 100 m Green Bank Telescope by means of three rotational transitions: 7(16)-8(08) at 41.5 GHz, 8(19)-9(09) at 23.2 GHz, and 9(18)-10(0), (10) at 4.9 GHz. Ketenimine has a sparse rotational spectrum below 50 GHz. From transition line strength arguments, the spectral lines found are the ones most likely to be detected, and they occur in spectral regions that have little possibility of confusion with other molecular species. Partially resolved hyperfine structure is apparent in the 4.9 GHz transition, which has energy levels similar to 50 K above the ground-state level; the absorption seen in this transition appears to be emanating from gas in close proximity to the LMH hot core that has a systemic LSR velocity of +64 km s(-1). By comparison, the 41.5 and 23.2 GHz transitions have lower energy levels of similar to 33 and similar to 41 K, respectively, and show absorption against the two star-forming Sgr B2( N) hot cores with systematic LSR velocities of +64 (the LMH) and similar to 82 km s(-1). These ketenimine data show that the hot core at +82 km s(-1) is cooler than the hot core at +64 km s(-1). Ketenimine is likely formed directly from its isomer methyl cyanide (CH3CN) by tautomerization driven by shocks that pervade the star-forming region. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. NASA, Goddard Space Flight Ctr, Computat & Informat Sci & Technol Off, Greenbelt, MD 20771 USA. Natl Radio Astron Observ, Charlottesville, VA 22903 USA. RP Lovas, FJ (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 21 TC 35 Z9 35 U1 0 U2 6 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 JUL 10 PY 2006 VL 645 IS 2 BP L137 EP L140 DI 10.1086/506324 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 063XW UT WOS:000239054200013 ER PT J AU Sui, LH Holman, GD Dennis, BR AF Sui, Linhui Holman, Gordon D. Dennis, Brian R. TI Motion of 3-6 keV nonthermal sources along the legs of a flare loop SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : flares; Sun : particle emission; Sun : X-rays, gamma rays ID X-RAY SOURCE; SOLAR-FLARE; MAGNETIC RECONNECTION; CHROMOSPHERIC HEIGHT; DENSITY-MEASUREMENTS; RHESSI; HARD; ENERGY; ELECTRONS; SPECTRA AB Observations of nonthermal X-ray sources are critical to the study of electron acceleration and transport in solar flares. Strong thermal emission radiated from the preheated plasma before the flare impulsive phase often makes it difficult to detect low-energy X-ray sources that are produced by relatively low-energy nonthermal electrons. Knowledge of the distribution of these low-energy nonthermal electrons is particularly important in determining the total nonthermal electron energy in solar flares. We report on an "early impulsive flare" in which impulsive hard X-ray emission was seen early in the flare before the soft X-ray emission had risen significantly, indicating limited plasma preheating. Early in the flare, RHESSI < 25 keV images show coronal sources that moved first downward and then upward along the legs of a flare loop. In particular, the 3-6 keV source appeared as a single coronal source at the start of the flare, and then it evolved into two coronal sources moving down along the two legs of the loop. After nearly reaching the two footpoints at the hard X-ray peak, the two sources moved back up to the looptop again. RHESSI images and light curves all indicate that nonthermal emission dominated at energies as low as 3-6 keV. We suggest that the evolution of both the spectral index and the low-energy cutoff of the injected electron distribution could result in the accelerated electrons reaching a lower altitude along the legs of the dense flare loop and hence result in the observed downward and upward motions of the nonthermal sources. C1 Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Greenbelt, MD 20771 USA. RP Sui, LH (reprint author), Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. RI Dennis, Brian/C-9511-2012; Holman, Gordon/C-9548-2012 NR 28 TC 26 Z9 27 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 JUL 10 PY 2006 VL 645 IS 2 BP L157 EP L160 DI 10.1086/506325 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 063XW UT WOS:000239054200018 ER PT J AU Wu, LG Zhang, Q Jiang, ZH AF Wu, Liguang Zhang, Qiang Jiang, Zhihong TI Three Gorges Dam affects regional precipitation SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PROJECT; CHINA AB [1] The impact of the Three Gorges Dam (TGD) on regional precipitation is examined through analysis of the National Aeronautics and Space Administration (NASA) Tropical Rainfall Measuring Mission (TRMM) rainfall rate and Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature and high-resolution simulation using the Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) fifth-generation Mesoscale Model (MM5). The independent satellite data sets and numerical simulation clearly indicate that the land use change associated with the TGD construction has increased the precipitation in the region between Daba and Qinling mountains and reduced the precipitation in the vicinity of the TGD after the TGD water level abruptly rose from 66 to 135 m in June 2003. This study suggests that the climatic effect of the TGD is on the regional scale (similar to 100 km) rather than on the local scale (similar to 10 km) as projected in previous studies. C1 Univ Maryland Baltimore Cty, Goddard Earth & Technol Ctr, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Atmospheres Lab, Greenbelt, MD USA. China Meteorol Adm, Natl Climate Ctr, Beijing 100081, Peoples R China. Nanjing Univ Informat Sci & Technol, Jiangsu Key Lab Meteorol Disaster, Nanjing 210044, Peoples R China. RP Wu, LG (reprint author), Univ Maryland Baltimore Cty, Goddard Earth & Technol Ctr, Baltimore, MD 21228 USA. EM liguang@agnes.gsfc.nasa.gov NR 8 TC 1 Z9 1 U1 1 U2 17 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 JUL 7 PY 2006 VL 33 IS 13 AR L13806 DI 10.1029/2006GL026780 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 062NR UT WOS:000238952300007 ER PT J AU Usmanov, AV Goldstein, ML AF Usmanov, A. V. Goldstein, M. L. TI A three-dimensional MHD solar wind model with pickup protons SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID LOCAL INTERSTELLAR-MEDIUM; OUTER HELIOSPHERE; DISTANT HELIOSPHERE; NEUTRAL HYDROGEN; TEMPERATURE; ULYSSES; TERMINATION; EVOLUTION; PLASMA; WAVES AB [ 1] We have developed a three-dimensional (3-D) steady-state MHD model of the solar corona and solar wind that covers the region from the coronal base to 100 AU and that accounts for the effects of pickup protons in the distant heliosphere. The model expands the two-region model of Usmanov and Goldstein ( 2003) to include a region III that extends from 1 - 100 AU and incorporates a population of interstellar neutral hydrogen and its interaction with solar wind protons. Following the approach of Isenberg ( 1986) and Whang ( 1998), we consider the solar wind outside 1 AU as a combination of three comoving species, solar wind protons, electrons, and pickup protons, and solve the 3-D steady-state MHD equations with source terms due to photoionization and charge exchange. Separate energy equations are included for solar wind and pickup protons. We show that the pickup protons cause a deceleration of the solar wind and an increase in average plasma temperature with heliocentric distance beyond similar to 10 AU. We compute the global structure of the solar wind from the coronal base to 100 AU and compare our results with Voyager 1 and 2 observations. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. RP Usmanov, AV (reprint author), NASA, Goddard Space Flight Ctr, Code 612-2, Greenbelt, MD 20771 USA. EM arcadi.usmanov@gsfc.nasa.gov; melvyn.l.goldstein@nasa.gov RI Goldstein, Melvyn/B-1724-2008; Usmanov, Arcadi/A-9860-2013 NR 36 TC 37 Z9 38 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-SPACE JI J. Geophys. Res-Space Phys. PD JUL 7 PY 2006 VL 111 IS A7 AR A07101 DI 10.1029/2005JA011533 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 062OJ UT WOS:000238954100006 ER PT J AU Pitts, MC Thomason, LW Zawodny, JM Wenny, BN Livingston, JM Russell, PB Yee, JH Swartz, WH Shetter, RE AF Pitts, M. C. Thomason, L. W. Zawodny, J. M. Wenny, B. N. Livingston, J. M. Russell, P. B. Yee, J. -H. Swartz, W. H. Shetter, R. E. TI Ozone observations by the Gas and Aerosol Measurement Sensor during SOLVE II SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID ABSORPTION-SPECTRUM; AIRBORNE; INSTRUMENT; NM AB The Gas and Aerosol Measurement Sensor ( GAMS) was deployed aboard the NASA DC-8 aircraft during the second SAGE III Ozone Loss and Validation Experiment ( SOLVE II). GAMS acquired line-of-sight (LOS) direct solar irradiance spectra during the sunlit portions of ten science flights of the DC-8 between 12 January and 4 February 2003. Differential line-of-sight (DLOS) optical depth spectra are produced from the GAMS raw solar irradiance spectra. Then, DLOS ozone number densities are retrieved from the GAMS spectra using a multiple linear regression spectral fitting technique. Both the DLOS optical depth spectra and retrieved ozone data are compared with coincident measurements from two other solar instruments aboard the DC-8 platform to demonstrate the robustness and stability of the GAMS data. The GAMS ozone measurements are then utilized to evaluate the quality of the Wulfband ozone cross sections, a critical component of the SAGE III aerosol, water vapor, and temperature/ pressure retrievals. Results suggest the ozone cross section compilation of Shettle and Anderson currently used operationally in SAGE III data processing may be in error by as much as 10 - 20% in the Wulf bands, and their lack of reported temperature dependence is a significant deficiency. A second, more recent, cross section database compiled for the SCIAMACHY satellite mission appears to be of much better quality in the Wulf bands, but still may have errors as large as 5% near the Wulf band absorption peaks, which is slightly larger than their stated uncertainty. Additional laboratory measurements of the Wulf band cross sections should be pursued to further reduce their uncertainty and better quantify their temperature dependence. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. Sci Applicat Int Corp, Hampton, VA USA. SRI Int, Menlo Pk, CA 94025 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Pitts, MC (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. EM michael.c.pitts@nasa.gov RI Swartz, William/A-1965-2010; OI Swartz, William/0000-0002-9172-7189; Thomason, Larry/0000-0002-1902-0840 NR 25 TC 5 Z9 6 U1 1 U2 3 PU COPERNICUS GESELLSCHAFT MBH PI GOTTINGEN PA BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY SN 1680-7316 EI 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JUL 6 PY 2006 VL 6 BP 2695 EP 2709 DI 10.5194/acp-6-2695-2006 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 060TJ UT WOS:000238824200002 ER PT J AU Richard, EC Tuck, AF Aikin, KC Kelly, KK Herman, RL Troy, RF Hovde, SJ Rosenlof, KH Thompson, TL Ray, EA AF Richard, E. C. Tuck, A. F. Aikin, K. C. Kelly, K. K. Herman, R. L. Troy, R. F. Hovde, S. J. Rosenlof, K. H. Thompson, T. L. Ray, E. A. TI High-resolution airborne profiles of CH4, O-3, and water vapor near tropical Central America in late January to early February 2004 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ANTARCTIC OZONE HOLE; LOWER STRATOSPHERE; AIRCRAFT OBSERVATIONS; TROPOPAUSE REGION; ICE; TROPOSPHERE; SPECTROMETER; DEHYDRATION; GREENHOUSE; CONVECTION AB [ 1] High-resolution ( 1 Hz at true airspeeds near 200 m s(-1)) observations of methane, ozone, water vapor, and temperature taken between the surface and 18 km from the WB57F aircraft near San Jose, Costa Rica (10 degrees N, 84 degrees W), are used to examine processes influencing the maintenance of these profiles. There was a clearly defined thermal tropopause on each of the eight profiles, accompanied by structure on methane-ozone scatterplots on the five profiles having methane observations. There was a well-defined decrease in methane mixing ratio between approximately 12 and 15 km in each of these five profiles, 2 - 5 km beneath the thermal tropopause, correlated with sharp changes in water vapor and equivalent potential temperature. The methane observations are interpreted as meaning that air is recirculated between the lower stratosphere and the upper tropical troposphere. At the point on each vertical profile where the water vapor had its minimum value, the air was never saturated or apparently supersaturated, although apparent supersaturation with respect to ice was observed in vertically extensive, near-adiabatic layers with tops some 200 - 300 m below the water vapor minimum on all profiles. One of the profiles also exhibited apparent supersaturation above its water vapor minimum, near 18 km. We examine the decrease in water vapor to minimal values as a four-stage process in which its mixing ratio was lowered from similar to 10 to similar to 3 ppmv, consider the role of solar and thermal evaporation of the smaller ice particles in the final stage of the dehydration process, and correlate features separating near-adiabatic layers above 150 hPa pressure altitude with local sea surface temperatures. C1 Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80303 USA. NOAA, Meteorol Chem Program, Div Chem Sci, Earth Syst Res Lab, Boulder, CO 80305 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Richard, EC (reprint author), Univ Colorado, Atmospher & Space Phys Lab, 1234 Innovat Dr, Boulder, CO 80303 USA. EM adrian.f.tuck@noaa.gov RI Tuck, Adrian/F-6024-2011; Rosenlof, Karen/B-5652-2008; Herman, Robert/H-9389-2012; Ray, Eric/D-5941-2013; Aikin, Kenneth/I-1973-2013; Manager, CSD Publications/B-2789-2015 OI Tuck, Adrian/0000-0002-2074-0538; Rosenlof, Karen/0000-0002-0903-8270; Herman, Robert/0000-0001-7063-6424; Ray, Eric/0000-0001-8727-9849; NR 34 TC 10 Z9 10 U1 0 U2 5 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 JUL 6 PY 2006 VL 111 IS D13 AR D13304 DI 10.1029/2005JD006513 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 062NY UT WOS:000238953000001 ER PT J AU Cooper, PD Moore, MH Hudson, RL AF Cooper, PD Moore, MH Hudson, RL TI Infrared detection of HO2 and HO3 radicals in water ice SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID MATRIX-ISOLATION; 80 K; SATELLITES; EUROPA; OZONE; HYDROPEROXY; RELEVANT; GANYMEDE; SPECTRA; SURFACE AB Infrared spectroscopy has been used to detect HO2 and HO3 radicals in H2O + O-2 ice mixtures irradiated with 0.8 MeV protons. In these experiments, HO2 was formed by the addition of an H atom to O-2 and HO3 was formed by a similar addition of H to O-3. The band positions observed for HO2 and HO3 in H2O-ice are 1142 and 1259 cm(-1), respectively, and these assignments were confirmed with O-18(2). HO2 and HO3 were also observed in irradiated H2O + O-3 ice mixtures, as well as in irradiated H2O2 ice. The astronomical relevance of these laboratory measurements is discussed. C1 NASA Goddard Space Flight Ctr, Astrochem Branch, Greenbelt, MD 20771 USA. Eckerd Coll, Dept Chem, St Petersburg, FL 33711 USA. RP Cooper, PD (reprint author), NASA Goddard Space Flight Ctr, Astrochem Branch, Code Branch,Code 691, Greenbelt, MD 20771 USA. EM paul.cooper@ssedmail.gsfc.nasa.gov RI Hudson, Reggie/E-2335-2012 NR 23 TC 37 Z9 37 U1 0 U2 13 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 JUL 6 PY 2006 VL 110 IS 26 BP 7985 EP 7988 DI 10.1021/jp062765k PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 058DR UT WOS:000238645600001 PM 16805481 ER PT J AU Rector, TJ Garland, JL Starr, SO AF Rector, TJ Garland, JL Starr, SO TI Dispersion characteristics of a rotating hollow fiber membrane bioreactor: Effects of module packing density and rotational frequency SO JOURNAL OF MEMBRANE SCIENCE LA English DT Article DE membrane bioreactor; hollow fiber contactor; mixing; mass transfer; dispersion ID BIOFILM REACTOR; DRINKING-WATER; MASS-TRANSFER; FLOW; DENITRIFICATION; NITRIFICATION; HYDRODYNAMICS; PERFORMANCE; AERATION AB The coupling of biological reactor with membrane dissolution processes has gained increasing attention in the wastewater treatment community because of their effective delivery of gaseous products and high treatment efficiencies. Turbulent flow may be an important factor for optimizing performance of these systems, both by reducing plug-flow conditions and associated axial gradients within the reactor and increasing mass transfer across the biofilm attached to membrane fibers. While turbulence is typically enhanced via increased flow velocity, rotation of the membranes themselves is an alternative mechanism for increasing turbulence that might eliminate problems associated with high flow (e.g., increased shear, mal-distribution of fluid flow). The effects of variable rotational frequencies (0, 5, 10 and 20 rpm) and membrane module packing densities (62, 82, 92%) on residence time distributions (RTD) curves of a bromide tracer were investigated to assess the potential for membrane rotation as a means of increasing turbulence. The resulting RTD curves were compared to a dispersive plug-flow model to determine the Peclet numbers (Pe) and subsequent axial dispersion coefficients. These finding indicated that increased dispersion is observed with increasing rotational frequency, with the effects of module packing density on dispersion characteristics decreasing with increased rotation. This study demonstrated that module rotation can cause turbulent flow prompting enhanced dispersion and allowing for low operational flow rates and reduction of mass transfer constraints associated with membrane bioreactors (MBR). (c) 2005 Elsevier B.V. All rights reserved. C1 Hamilton Sundstrand Space Land & Sea Int, Dept Adv Technol, Windsor Locks, CT 06096 USA. Dynamac Corp, Space Life Sci Lab, Kennedy Space Ctr, FL 32899 USA. NASA, Kennedy Space Ctr, FL 32899 USA. RP Rector, TJ (reprint author), Hamilton Sundstrand Space Land & Sea Int, Dept Adv Technol, 1 Hamilton RD,1A-2-W66, Windsor Locks, CT 06096 USA. EM tony.rector@hs.utc.com NR 20 TC 18 Z9 18 U1 6 U2 29 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0376-7388 J9 J MEMBRANE SCI JI J. Membr. Sci. PD JUL 5 PY 2006 VL 278 IS 1-2 BP 144 EP 150 DI 10.1016/j.memsci.2005.10.050 PG 7 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA 054WM UT WOS:000238409300016 ER PT J AU Zypman, FR Ferrante, J AF Zypman, F. R. Ferrante, J. TI Gradient equivalent crystal theory SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID SURFACES AB This paper presents an extension of the formalism of equivalent crystal theory (ECT) by introducing an electron density gradient term so that the total model density becomes a more accurate representation of the real local density. Specifically, we allow for the electron density around a lattice site to have directionality, in addition to an average value, as assumed in ECT. We propose that an atom senses its neighbouring density as a weighted sum-the weights given by the its own electronic probability. As a benchmark, the method is used to compute vacancy migration energy curves of iron. These energies are in good agreement with previously published results. C1 Yeshiva Univ, Dept Phys, New York, NY 10033 USA. NASA Glenn, Cleveland, OH 44135 USA. RP Zypman, FR (reprint author), Yeshiva Univ, Dept Phys, New York, NY 10033 USA. NR 6 TC 2 Z9 2 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 EI 1361-648X J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD JUL 5 PY 2006 VL 18 IS 26 BP 6095 EP 6099 DI 10.1088/0953-8984/18/26/027 PG 5 WC Physics, Condensed Matter SC Physics GA 057RL UT WOS:000238612800030 PM 21690822 ER PT J AU Rosario-Castro, BI Fachini, ER Hernandez, J Perez-Davis, ME Cabrera, CR AF Rosario-Castro, Belinda I. Fachini, Estevao R. Hernandez, Jessica Perez-Davis, Marla E. Cabrera, Carlos R. TI Electrochemical and surface characterization of 4-aminothiophenol adsorption at polycrystalline platinum electrodes SO LANGMUIR LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; WALLED CARBON NANOTUBES; REDUCTIVE DESORPTION; ALKANETHIOLATE MONOLAYERS; MOLECULAR ASSEMBLIES; GOLD SURFACES; 3-MERCAPTOPROPYLTRIMETHOXYSILANE; AMINE; FILMS; ACIDS AB The formation of a self-assembled monolayer (SAM) of 4-aminothiophenol (4-ATP) on polycrystalline platinum electrodes has been characterized by surface analysis and electrochemistry techniques. The 4-ATP monolayer was characterized by cyclic voltammetry (CV), linear sweep voltammetry, Raman spectroscopy, reflection-absorption infrared (RAIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). CV was used to study the dependence of the adsorption time and 4-ATP solution concentration on the relative degree of coverage of 4-ATP monolayers on polycrystalline Pt electrodes. The adsorption time range probed was 24-72 h. The optimal concentration of 4-ATP needed to obtain the highest surface at the lowest adsorption time was 10 mM. RAIR and Raman spectroscopy for 4-ATP-modified platinum electrodes showed the characteristic adsorption bands for 4-ATP, such as nu NH, nu CHarom, and nu CSarom, indicating the adsorption on the platinum surface. The XPS spectra for the modified Pt surface presented the binding energy peaks of sulfur and nitrogen. High energy resolution XPS studies, RAIR, and Raman spectrum for platinum electrodes modified with 4-ATP indicate that the molecules are sulfur-bonded to the platinum surface. The formation of a S-Pt bond suggests that ATP adsorption leads to an amino-terminated electrode surface. The thickness of the monolayer was evaluated via angle-resolved XPS (AR-XPS) analyses, giving a value of 8 angstrom. As evidence of the terminal amino group on the electrode surface, the chemical derivatization of the 4-ATP SAM was done with 16-Br hexadecanoic acid. This surface reaction was followed by RAIR spectroscopy. C1 NASA, Electrochem Branch, John H Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Puerto Rico, Dept Chem, Rio Piedras, PR 00931 USA. Univ Puerto Rico, Ctr Nanoscale Mat, San Juan, PR 00931 USA. RP Perez-Davis, ME (reprint author), NASA, Electrochem Branch, John H Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM marla.e.perez-davis@grc.nasa.gov; ccabrera@uprrp.edu OI Cabrera, Carlos/0000-0002-3342-8666 NR 44 TC 38 Z9 38 U1 2 U2 25 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD JUL 4 PY 2006 VL 22 IS 14 BP 6102 EP 6108 DI 10.1021/la0522193 PG 7 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 056XN UT WOS:000238558500022 PM 16800665 ER PT J AU Lehnert, H Stone, R Heimler, W AF Lehnert, Helmut Stone, Robert Heimler, Wolfgang TI New species of deep-sea demosponges (Porifera) from the Aleutian Islands (Alaska, USA) SO ZOOTAXA LA English DT Article DE Porifera; Poecilosclerida; new species; taxonomy; Aleutian Islands; N-Pacific; deep-sea AB Deep-sea sponge habitat of the Aleutian Islands was investigated with the ROV Jason II. Identification of the more than 60 specimens collected at depths between 179 and 2827 m revealed nine new species of demosponges. Megaciella anisochela sp. nov., Stelodoryx oxeata sp. nov, Monanchora laminachela sp. nov, Echinoclathria vasa sp. nov., Euchelipluma elongata sp. nov., Esperiopsis flagrum sp. nov., Mycale jasoniae sp. nov., Latrunculia velera sp. nov. and Latrunculia occulta sp. nov. are described and compared with congeners of the area. C1 Natl Marine Fisheries Serv, Auke Bay Lab, Juneau, AK 99801 USA. Univ Erlangen Nurnberg, Inst Zool 1, D-91054 Erlangen, Germany. RP Lehnert, H (reprint author), Eichenstr 14, D-86507 Oberottmarshausen, Germany. EM Helm.Lehnert@t-online.de NR 63 TC 0 Z9 0 U1 1 U2 1 PU MAGNOLIA PRESS PI AUCKLAND PA PO BOX 41383, AUCKLAND, ST LUKES 1030, NEW ZEALAND SN 1175-5326 EI 1175-5334 J9 ZOOTAXA JI Zootaxa PD JUL 3 PY 2006 IS 1250 BP 1 EP 35 PG 35 WC Zoology SC Zoology GA 066XF UT WOS:000239263200001 ER PT J AU Wood, L Curiel, AD Ivancic, W Hodgson, D Shell, D Jackson, C Stewart, D AF Wood, L Curiel, AD Ivancic, W Hodgson, D Shell, D Jackson, C Stewart, D TI Operating a terrestrial Internet router onboard and alongside a small satellite SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 56th Congress of the International-Astronautical-Federation CY OCT 17-21, 2005 CL Fukuoka, JAPAN SP Int Astronaut Fed AB After twenty months of flying, testing and demonstrating a Cisco mobile access router, originally designed for terrestrial use, onboard the low-Earth-orbiting UK-DMC satellite as part of a larger merged ground/space IP-based internetwork, we use our experience to examine the benefits and drawbacks of integration and standards reuse for small satellite missions. Benefits include ease of operation and the ability to leverage existing systems and infrastructure designed for general use with a large set of latent capabilities to draw on when needed, as well as the familiarity that comes from reuse of existing, known, and well-understood security and operational models. Drawbacks include cases where integration work was needed to bridge the gaps in assumptions between different systems, and where performance considerations outweighed the benefits of reuse of pre-existing file transfer protocols. We find similarities with the terrestrial IP networks whose technologies have been taken to small satellites-and also some significant differences between the two in operational models and assumptions that must be home in mind. Crown Copyright (C) 2006 Published by Elsevier Ltd. All rights reserved. C1 Cisco Syst Global Def, Space & Secur, London, England. Univ Surrey, Surrey Satellite Technol Ltd, Guildford GU2 5XH, Surrey, England. NASA, Glenn Res Ctr, Cleveland, OH USA. Univ Surrey, DMC Int Imaging, Guildford GU2 5XH, Surrey, England. Cisco Syst Govt Serv Unit, Richfield, OH USA. Verizon Fed Network Syst, Cleveland, OH USA. RP Wood, L (reprint author), Cisco Syst Global Def, Space & Secur, Bedfont Lakes, London, England. EM lwood@cisco.com NR 7 TC 0 Z9 0 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 JUL-SEP PY 2006 VL 59 IS 1-5 BP 124 EP 131 DI 10.1016/j.actaastro.2006.02.026 PG 8 WC Engineering, Aerospace SC Engineering GA 057WP UT WOS:000238626200018 ER PT J AU O'Neill, M Howell, J Lollar, L Carrington, C Suzuki, N Piszczor, M Hoppe, D Eskenazi, M Aiken, D Fulton, M Brandhorst, H Schuller, M McDanal, AJ AF O'Neill, M Howell, J Lollar, L Carrington, C Suzuki, N Piszczor, M Hoppe, D Eskenazi, M Aiken, D Fulton, M Brandhorst, H Schuller, M McDanal, AJ TI Stretched lens array squarerigger (SLASR): A unique high-power solar array for exploration missions SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 56th Congress of the International-Astronautical-Federation CY OCT 17-21, 2005 CL Fukuoka, JAPAN SP Int Astronaut Fed AB Over the past two years, development has begun on a unique high-power solar concentrator array called stretched lens array squarerigger (SLASR). SLASR marries the high electrical performance and low mass of the ENTECH stretched lens array (SLA) flexible blanket concentrator with the high structural performance and low mass of the ATK space squarerigger (SR) platform. SLASR offers unprecedented performance metrics for a space solar array of any type, including: high power capacity (100 kW to multi-MW Class) compact launch stowage (80-120 kW/m(3)) state of the art areal power density (300-400W/m(2)) outstanding array-level specific power (300-1000 W/kg) high-voltage operation at low insulation mass penalty (300-600V) excellent manufacturability using proven processes (cells and lenses at MWs/year) improved radiation hardness at low shielding mass penalty (enabling solar electric propulsion space tugs through the radiation belts) exceptional cost effectiveness (50-75 percent less than high-efficiency planar arrays) This paper describes SLASR technology, discusses SLASR developments to date, and outlines plans for SLASR technology maturation. The advantages of SLASR over other high-power solar array technologies are presented, including a comparison of key performance parameters for large-scale solar electric propulsion space tug missions. (C) 2006 Elsevier Ltd. All rights reserved. C1 NASA, MSFC, Moffett Field, CA USA. NASA, HQ, Greenbelt, MD USA. NASA, GRC, Greenbelt, MD USA. Auburn Univ, Auburn, AL 36849 USA. Texas A&M Univ, College Stn, TX 77843 USA. EM mjoneill@entechsolar.com; joe.howell@nasa.gov; louis.flollar@nasa.gov; connie.k.carrington@nasa.gov; nantel.h.suzuki@nasa.gov; michael.f.piszczor@nasa.gov; david.t.hoppe@nasa.gov; mike.eskenazi@atk.com; dan_aiken@emcore.com; mfulton@ionbeamoptics.com; brandhh@auburn.edu; schuller@tamu.edu; ajmcdanal@entechsolar.com NR 13 TC 2 Z9 2 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 JUL-SEP PY 2006 VL 59 IS 1-5 BP 157 EP 165 DI 10.1016/j.actaastro.2006.02.011 PG 9 WC Engineering, Aerospace SC Engineering GA 057WP UT WOS:000238626200022 ER PT J AU Voland, RT Huebner, LD McClinton, CR AF Voland, RT Huebner, LD McClinton, CR TI X-43A hypersonic vehicle technology development SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 56th Congress of the International-Astronautical-Federation CY OCT 17-21, 2005 CL Fukuoka, JAPAN SP Int Astronaut Fed AB NASA recently completed two major programs in hypersonics: Hyper-X, with the record-breaking flights of the X-43A, and the next generation launch technology (NGLT) program. The X-43A flights, the culmination of the Hyper-X program, were the ftrst-ever examples of a scramjet engine propelling a hypersonic vehicle and provided unique, convincing, detailed flight data required to validate the design tools needed for design and development of future operational hypersonic airbreathing vehicles. Concurrent with Hyper-X, NASAs NGLT program focused on technologies needed for future revolutionary launch vehicles. The NGLT was "competed" by NASA in response to the President's redirection of the agency to space exploration, after making significant progress towards maturing technologies required to enable airbreathing hypersonic launch vehicles. NGLT quantified the benefits, identified technology needs, developed airframe and propulsion technology, chartered a broad University base, and developed detailed plans to mature and validate hypersonic airbreathing technology for space access. NASA is currently in the process of defining plans for a new hypersonic technology program. Details of that plan are not currently available. This paper highlights results from the successful Mach 7 and 10 flights of the X-43A, and the current state of hypersonic technology. (C) 2006 Published by Elsevier Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Voland, RT (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 40 TC 45 Z9 54 U1 6 U2 44 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 JUL-SEP PY 2006 VL 59 IS 1-5 BP 181 EP 191 DI 10.1016/j.actaastro.2006.02.021 PG 11 WC Engineering, Aerospace SC Engineering GA 057WP UT WOS:000238626200025 ER PT J AU Howell, JT O'Neill, MJ Mankins, JC AF Howell, JT O'Neill, MJ Mankins, JC TI High-voltage array ground test for direct-drive solar electric propulsion SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 56th Congress of the International-Astronautical-Federation CY OCT 17-21, 2005 CL Fukuoka, JAPAN SP Int Astronaut Fed AB Development is underway on a unique high-power solar concentrator array called stretched lens array (SLA) for direct drive electric propulsion. These SLA performance attributes closely match the critical needs of solar electric propulsion (SEP) systems, which may be used for "space tugs" to fuel-efficiently transport cargo from low Earth orbit (LEO) to low lunar orbit (LLO), in support of NASA's robotic and human exploration missions. Later SEP systems may similarly transport cargo from the Earth-Moon neighborhood to the Mars neighborhood. This paper will describe the SLA SEP technology, discuss ground tests already completed, and present plans for future ground tests and future flight tests of SLA SEP systems. (C) 2006 Published by Elsevier Ltd. C1 NASA, George C Marshall Space Flight Ctr, Adv Projects Team, Huntsville, AL 35812 USA. ENTECH Inc, Keller, TX 76248 USA. Artemis Innovat Management Solut LLC, Ashburn, VA USA. RP Howell, JT (reprint author), NASA, George C Marshall Space Flight Ctr, Adv Projects Team, SP20, Huntsville, AL 35812 USA. EM Joe.Howell@nasa.gov; mjoneill@entechsolar.com; john.c.mankins@artemisinnovation.com NR 18 TC 0 Z9 0 U1 0 U2 1 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 JUL-SEP PY 2006 VL 59 IS 1-5 BP 206 EP 215 DI 10.1016/j.actaastro.2006.02.050 PG 10 WC Engineering, Aerospace SC Engineering GA 057WP UT WOS:000238626200028 ER PT J AU Howell, JT Mankins, JC John, CF AF Howell, JT Mankins, JC John, CF TI In-space cryogenic propellant depot stepping stone SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 56th Congress of the International-Astronautical-Federation CY OCT 17-21, 2005 CL Fukuoka, JAPAN SP Int Astronaut Fed AB An In-Space Cryogenic Propellant Depot (ISCPD) is an important stepping stone to provide the capability to preposition, store, manufacture, and later use the propellants for Earth-neighborhood campaigns and beyond. An in-space propellant depot will provide affordable propellants and other similar consumables to support the development of sustainable and affordable exploration strategies as well as commercial space activities. An in-space propellant depot not only requires technology development in key areas such as zero boil-off storage and fluid transfer, but in other areas such as lightweight structures, highly reliable connectors, and autonomous operations. These technologies can be applicable to a broad range of propellant depot concepts or specific to a certain design. In addition, these technologies are required for spacecraft and orbit transfer vehicle propulsion and power systems, and space life support. Generally, applications of this technology require long-term storage, on-orbit fluid transfer and supply, cryogenic propellant production from water, unique instrumentation and autonomous operations. This paper discusses the reasons why such advances are important to future affordable and sustainable operations in space. This paper also discusses briefly R&D objectives comprising a promising approach to the systems planning and evolution into a meaningful stepping stone design, development, and implementation of an ISCPD. The success of a well-planned and orchestrated approach holds great promise for achieving innovation and revolutionary technology development for supporting future exploration and development of space. (C) 2006 Published by Elsevier Ltd. C1 NASA, George C Marshall Space Flight Ctr, Adv Projects Team, Huntsville, AL 35812 USA. Artemis Innovat Management Solut LLC, Ashburn, VA USA. RP Howell, JT (reprint author), NASA, George C Marshall Space Flight Ctr, Adv Projects Team, SP20, Huntsville, AL 35812 USA. EM Joe.Howell@nasa.gov; john.c.mankins@artemisinnovation.com; john.c.fikes@nasa.gov NR 0 TC 2 Z9 2 U1 3 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 JUL-SEP PY 2006 VL 59 IS 1-5 BP 230 EP 235 DI 10.1016/j.actaastro.2006.02.019 PG 6 WC Engineering, Aerospace SC Engineering GA 057WP UT WOS:000238626200031 ER PT J AU Edwards, CD Arnold, B DePaula, R Kazz, G Lee, C Noreen, G AF Edwards, CD Arnold, B DePaula, R Kazz, G Lee, C Noreen, G TI Relay communications strategies for Mars exploration through 2020 SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 56th Congress of the International-Astronautical-Federation CY OCT 17-21, 2005 CL Fukuoka, JAPAN SP Int Astronaut Fed ID MISSION AB Mars exploration poses significant telecommunications challenges, including the return of large data volumes from high-resolution surface instruments, highly constrained mass, power, and energy for surface spacecraft, frequent telemetry and command sessions for supporting complex surface operations, and high-risk mission events such as entry, descent, and landing for which the capture of engineering telemetry is deemed critical. Relay telecommunication via Mars-orbiting spacecraft offers significant advantages in meeting these challenges, relative to conventional direct-to-Earth communications. NASA's Mars Global Surveyor and Mars Odyssey orbiters, along with ESA's Mars Express orbiter, represent an initial relay telecommunications infrastructure that has successfully supported the Spirit and Opportunity rovers. With the arrival of the Mars Reconnaissance Orbiter in 2006, this expanded relay network will provide key support to the 2007 Phoenix Lander and 2009 Mars Science Laboratory missions later this decade. Second-decade mission concepts will introduce new communications challenges; the provision of relay payloads on science orbiters provides a cost-effective means to sustain and evolve the Mars relay network. (C) 2006 Elsevier Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA Headquarters, Washington, DC 20546 USA. RP Edwards, CD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM chad.edwards@jpl.nasa.gov NR 10 TC 5 Z9 5 U1 1 U2 4 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 JUL-SEP PY 2006 VL 59 IS 1-5 BP 310 EP 318 DI 10.1016/j.actaastro.2006.02.038 PG 9 WC Engineering, Aerospace SC Engineering GA 057WP UT WOS:000238626200042 ER PT J AU Mitchell, RT AF Mitchell, RT TI Cassini/Huygens at Saturn and Titan SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 56th Congress of the International-Astronautical-Federation CY OCT 17-21, 2005 CL Fukuoka, JAPAN SP Int Astronaut Fed AB The Cassini/Huygens Project is a joint undertaking between NASA, the European Space Agency, and the Italian Space Agency to conduct an in-depth exploration of the Saturnian system. The spacecraft consists of an orbiter vehicle and an atmospheric probe which has completed its mission in the atmosphere and on the surface of Titan, the largest moon of Saturn. The spacecraft was launched on October 15, 1997, has completed its nearly 7 years of interplanetary flight, and by the time of the 56th IAC, it will have completed 17 of its planned 75 orbits during its 4-year prime orbital mission. This paper gives an overview of the mission, and describes in detail the accomplishments and events over the past year, including the spectacularly successful descent of the European Space Agency's Huygens probe to the surface of Titan. Initial scientific results from both the Huygens mission as well as from the first one-and-a-quarter years of orbiting Saturn are summarized. The plans for the remainder of the orbiter's tour of the Saturn system and the many flybys of Titan and the smaller icy satellites are described. (C) 2006 Elsevier Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Mitchell, RT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. EM rmitchel@jpl.nasa.gov NR 5 TC 0 Z9 0 U1 0 U2 1 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 JUL-SEP PY 2006 VL 59 IS 1-5 BP 335 EP 343 DI 10.1016/j.actaastro.2006.02.040 PG 9 WC Engineering, Aerospace SC Engineering GA 057WP UT WOS:000238626200044 ER PT J AU Sudbrack, CK Yoon, KE Noebe, RD Seidman, DN AF Sudbrack, Chantal K. Yoon, Kevin E. Noebe, Ronald D. Seidman, David N. TI Temporal evolution of the nanostructure and phase compositions in a model Ni-Al-Cr alloy SO ACTA MATERIALIA LA English DT Article DE nanostructure; nucleation of phase transformations; coarsening; Ni alloys; atom-probe tomography ID 3-DIMENSIONAL ATOM-PROBE; MONTE-CARLO SIMULATIONS; NUMBER DENSITY; PRECIPITATE; DECOMPOSITION; NUCLEATION; SCALE; SUPERALLOYS; MICROSCOPY; PARTICLES AB In a Ni-5.2 Al-14.2 Cr at.% alloy with moderate solute supersaturations and a very small -gamma/gamma' lattice parameter misfit. the nanostructural and compositional pathways during gamma'(L1(2)) precipitation at S73 K are investigated using atom-probe tomography. conventional transmission electron microscopy, and hardness measurements. Nucleation of high number densities (N-v > 10(23) m(-3)) of solute-rich precipitates (mean radius = < R > = 0.75 nm), with a critical nucleus composition of Ni-18.3 +/- 0.9 Al-9.3 +/- 0.7 Cr at.%. initiates between 0.0833 and 0.167 h. With increasing aging time (a) the solute concentrations decay in spheroidal precipitates (< R > < 10 nm): (b) the observed early-stage coalescence peaks at maximum N-v in coincidence with the smallest interprecipitate spacing: and (c) the reaction enters a quasi-stationary regime where growth and coarsening operate concomitantly. During this quasi-stationary regime. the (face-centered cubic)-matrix Solute supersaturations decay with a power-law dependence of about -1/3. while the dependencies of < R > and N-v are 0.29 +/- 0.05 and -0.64 +/- 0.06 at a coarsening rate slower than model predications. Coarsening models allow both equilibrium phase compositions to be determined from the compositional measurements. The observed early-stage coalescence is discussed in further detail. (c) 2006 Acta Materialia Inc. Published bv Elsevier Ltd. All rights reserved. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. NASA Glenn Res Ctr, Cleveland, OH 44135 USA. RP Seidman, DN (reprint author), Argonne Natl Lab, Mat Sci Div, 9700 S Cass Ave, Chicago, IL 60439 USA. EM csudbrack@alumni.reed.edu; d-seidman@northwestern.edu RI Seidman, David/B-6697-2009 NR 52 TC 56 Z9 60 U1 5 U2 15 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 JUL PY 2006 VL 54 IS 12 BP 3199 EP 3210 DI 10.1016/j.actamat.2006.03.015 PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 065EM UT WOS:000239142200005 ER PT J AU Rediess, HA Garg, S AF Rediess, Herman A. Garg, Sanjay TI Autonomous civil aircraft - the future of aviation? SO AEROSPACE AMERICA LA English DT Article C1 Natl Inst Aerosp, Hampton, VA USA. NASA Glenn, Controls & Dynam Branch, Cleveland, OH USA. RP Rediess, HA (reprint author), Natl Inst Aerosp, Hampton, VA USA. NR 0 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 0740-722X J9 AEROSPACE AM JI Aerosp. Am. PD JUL PY 2006 VL 44 IS 7 BP 40 EP 43 PG 4 WC Engineering, Aerospace SC Engineering GA 063VL UT WOS:000239047900017 ER PT J AU Rumsey, CL Reif, BAP Gatski, TB AF Rumsey, C. L. Reif, B. A. Pettersson Gatski, T. B. TI Arbitrary steady-state solutions with the K-epsilon model SO AIAA JOURNAL LA English DT Article ID TURBULENCE MODELS; FLOWS AB Widely used forms of the K-epsilon turbulence model are shown to yield arbitrary steady-state converged solutions that are highly dependent on numerical considerations such as initial conditions and solution procedure. These solutions contain pseudo-laminar regions of varying size, which can occur even when attempting to use the K-epsilon model within its intended scope as a fully turbulent computation. By applying a nullcline analysis to the equation set, it is possible to clearly demonstrate the reasons for the anomalous behavior. In summary, use of a low-Reynoldsnumber damping term in the epsilon equation causes the degenerate solution to act as a stable fixed point under certain conditions, in turn causing the numerical method to converge there. The analysis also suggests a methodology for preventing the anomalous behavior in steady-state computations. C1 NASA, Langley Res Ctr, Computat Aerosci Branch, Hampton, VA 23681 USA. Norwegian Def Res Estab, NO-2027 Kjeller, Norway. Chalmers Univ Technol, Dept Appl Mech, SE-41296 Gothenburg, Sweden. RP Rumsey, CL (reprint author), NASA, Langley Res Ctr, Computat Aerosci Branch, Hampton, VA 23681 USA. EM c.l.rumsey@nasa.gov; bjorn.reif@ffi.no; t.b.gatski@widomaker.com NR 12 TC 18 Z9 18 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 JUL PY 2006 VL 44 IS 7 BP 1586 EP 1592 DI 10.2514/1.18015 PG 7 WC Engineering, Aerospace SC Engineering GA 063UV UT WOS:000239046300024 ER PT J AU Harvey, DJ Das, SK Biswas, R AF Harvey, DJ Das, SK Biswas, R TI Design and performance of a heterogeneous grid partitioner SO ALGORITHMICA LA English DT Article DE grid computing; dynamic load balancing; graph partitioning; latency tolerance; N-body problem; heterogeneous distributed environments; performance analysis ID ALGORITHM AB An important characteristic of distributed grids is that they allow geographically separated multicomputers to be tied together in a transparent virtual environment to solve large-scale computational problems. However, many of these applications require effective runtime load balancing for the resulting solutions to be viable. In this paper we present a novel latency-tolerant partitioner, called MinEX, that dynamically balances processor workloads while minimizing data movement and runtime communication for applications that are executed in a parallel distributed grid environment. We also compare the performance of MinEX with that of METIS, a popular multilevel family of partitioners, using simulated heterogeneous grid configurations. A solver for the classical N-body problem is implemented to provide a framework for the comparisons. Experimental results show that the proposed MinEX partitioner provides superior quality partitions while being competitive to METIS in terms of execution speed. C1 So Oregon Univ, Dept Comp Sci, Ashland, OR 97520 USA. Univ Texas, Dept Comp Sci, Arlington, TX 76019 USA. NASA, Ames Res Ctr, NAS Div, Moffett Field, CA 94035 USA. RP Harvey, DJ (reprint author), So Oregon Univ, Dept Comp Sci, Ashland, OR 97520 USA. EM harveyd@sou.edu; das@cse.uta.edu; rbiswas@nas.nasa.gov NR 27 TC 6 Z9 6 U1 0 U2 1 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0178-4617 J9 ALGORITHMICA JI Algorithmica PD JUL PY 2006 VL 45 IS 3 BP 509 EP 530 DI 10.1007/s00453-006-1223-0 PG 22 WC Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA 051IA UT WOS:000238153600011 ER PT J AU Van Acker, MRMD Shahar, A Young, ED Coleman, ML AF Van Acker, MRMD Shahar, A Young, ED Coleman, ML TI GC/multiple collector-ICPMS method for chlorine stable isotope analysis of chlorinated aliphatic hydrocarbons SO ANALYTICAL CHEMISTRY LA English DT Article ID MASS-SPECTROMETRY; CARBON; SOLVENTS; SAMPLES AB Stable isotopic characterization of chlorine in chlorinated aliphatic pollution is potentially very valuable for risk assessment and monitoring remediation or natural attenuation. The approach has been underused because of the complexity of analysis and the time it takes. We have developed a new method that eliminates sample preparation. Gas chromatography produces individually eluted sample peaks for analysis. The He carrier gas is mixed with Ar and introduced directly into the torch of a multicollector ICPMS. The MC-ICPMS is run at a high mass resolution of >= 10 000 to eliminate interference of mass 37 ArH with Cl. The standardization approach is similar to that for continuous flow stable isotope analysis in which sample and reference materials are measured successively. We have measured PCE relative to a laboratory TCE standard mixed with the sample. Solvent samples of 200 nmol to 1.3 mu mol ( 24- 165 mu g of Cl) were measured. The PCE gave the same value relative to the TCE as measured by the conventional method with a precision of 0.12% ( 2 x standard error) but poorer precision for the smaller samples. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Reading, Sch Human & Environm Sci, Reading RG6 6AB, Berks, England. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. RP Coleman, ML (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM max.coleman@jpl.nasa.gov RI Coleman, Max/A-1303-2007; OI Coleman, Max/0000-0002-5514-1826; Shahar, Anat/0000-0002-0794-2717 NR 16 TC 31 Z9 31 U1 1 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUL 1 PY 2006 VL 78 IS 13 BP 4663 EP 4667 DI 10.1021/ac0602120 PG 5 WC Chemistry, Analytical SC Chemistry GA 058KZ UT WOS:000238665200057 PM 16808479 ER PT J AU Liu, HL Quijada, M Romero, DB Tanner, DB Zibold, A Carr, GL Berger, H Forro, L Mihaly, L Cao, G O, BH Markert, JT Rice, JP Burns, MJ Delin, KA AF Liu, H. L. Quijada, M. Romero, D. B. Tanner, D. B. Zibold, A. Carr, G. L. Berger, H. Forro, L. Mihaly, L. Cao, G. O, Beom-Hoan Markert, J. T. Rice, J. P. Burns, M. J. Delin, K. A. TI Drude behavior in the far-infrared conductivity of cuprate superconductors SO ANNALEN DER PHYSIK LA English DT Article DE infrared; Drude; cuprate ID T-C SUPERCONDUCTORS; SINGLE-CRYSTALS; THIN-FILMS; YBA2CU3O7-DELTA; RESISTIVITY; STATE; BI2SR2CACU2O8; SCATTERING; ANISOTROPY; PSEUDOGAP AB When viewed at frequencies below about 8 THz (250 cm(-1); 30 meV) the ab-plane optical conductivity of the cuprate superconductors (in their normal state) is well described by a Drude model. Examples include optimally-doped YBa2Cu3O7-delta and Bi2Sr2CaCu2O8; even the underdoped phases have a Drude character to their optical conductivity. A residual Drude-like normal fluid is seen in the superconducting state in most cases; the scattering rate of this quasiparticle contribution collapses at T-c. (C) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. C1 Univ Florida, Dept Phys, Gainesville, FL 32611 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Ecole Polytech Fed Lausanne, CH-1015 Lausanne, Switzerland. SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32306 USA. Univ Texas, Dept Phys, Austin, TX 78712 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Illinois, Mat Res Lab, Urbana, IL 61801 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tanner, DB (reprint author), Univ Florida, Dept Phys, Gainesville, FL 32611 USA. EM hliu@phy.ntnu.edu.tw; manuel.a.quijada@nasa.gov; dbromero@nist.gov; tanner@phys.ufl.edu; Axel.Zibold@t-online.de; carr@bnl.gov RI Burns, Michael/D-2939-2011 OI Burns, Michael/0000-0001-9804-405X NR 41 TC 6 Z9 6 U1 0 U2 5 PU WILEY-V C H VERLAG GMBH PI WEINHEIM PA POSTFACH 101161, 69451 WEINHEIM, GERMANY SN 0003-3804 EI 1521-3889 J9 ANN PHYS-BERLIN JI Ann. Phys.-Berlin PD JUL-AUG PY 2006 VL 15 IS 7-8 BP 606 EP 618 DI 10.1002/andp.200510205 PG 13 WC Physics, Multidisciplinary SC Physics GA 064QY UT WOS:000239105400015 ER PT J AU Sorensen, KB Teske, A AF Sorensen, Ketil B. Teske, Andreas TI Stratified communities of active archaea in deep marine subsurface sediments SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID 16S RIBOSOMAL-RNA; SUBSEAFLOOR SEDIMENTS; MICROBIAL COMMUNITIES; PHYLOGENETIC ANALYSIS; SEA SEDIMENTS; PACIFIC-OCEAN; GROWTH-RATE; DIVERSITY; BACTERIA; PROKARYOTES AB Archaeal 16S rRNA was extracted from samples of deep marine subsurface sediments from Peru Margin site 1227, Ocean Drilling Program leg 201. The amounts of archaeal 16S rRNA in each extract were quantified by serial dilution and reverse transcription (RT)-PCR. The results indicated a 1,000-fold variation in rRNA content with depth in the sediment, with the highest concentrations found near the sediment surface and in the sulfate-methane transition zone (SMTZ). The phylogenetic composition of the active archaeal population revealed by cloning and sequencing of RT-PCR products changed with depth. Several phylotypes affiliated with marine benthic group B (MBGB) dominated clone libraries from the upper part of the SMTZ and were detected only in this layer. Members of the miscellaneous crenarchaeotal group (MCG) dominated clone libraries from the other layers. These results demonstrate that archaeal communities change in activity and community composition over short distances in geochemically distinct zones of deep subseafloor sediments and that these changes are traceable in the rRNA pool. It was shown for the first time that members of both the MCG and MBGB Archaea are more active in the SMTZ than in layers above and below. This indicates that they benefit either directly or indirectly from the anaerobic oxidation of methane. They also appear to be ecophysiologically flexible, as they have been retrieved from a wide range of marine sediments of various geochemical properties. C1 Univ N Carolina, NASA Astrobiol Inst, Marine Sci Dept, Chapel Hill, NC 27599 USA. RP Teske, A (reprint author), Univ N Carolina, NASA Astrobiol Inst, Marine Sci Dept, 12-7 Venable Hall,CB 3300, Chapel Hill, NC 27599 USA. EM teske@email.unc.edu NR 55 TC 116 Z9 126 U1 0 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 JUL PY 2006 VL 72 IS 7 BP 4596 EP 4603 DI 10.1128/AEM.00562-06 PG 8 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 062RA UT WOS:000238961000013 PM 16820449 ER PT J AU Langley, P Shiran, O Shrager, J Todorovski, L Pohorille, A AF Langley, Pat Shiran, Oren Shrager, Jeff Todorovski, Ljupco Pohorille, Andrew TI Constructing explanatory process models from biological data and knowledge SO ARTIFICIAL INTELLIGENCE IN MEDICINE LA English DT Article DE computational scientific discovery; inductive process modeling; photosynthesis regulation; biochemical kinetic reactions AB Objective: We address the task of inducing explanatory models from observations and knowledge about candidate biological processes, using the illustrative problem of modeling photosynthesis regulation. Methods: We cast both models and background knowledge in terms of processes that interact to account for behavior. We also describe IPM, an algorithm for inducing quantitative process models from such input. Results: We demonstrate IPM's use both on photosynthesis and on a second domain, biochemical kinetics, reporting the models induced and their fit to observations. Conclusion: We consider the generality of our approach, discuss related research on biological modeling, and suggest directions for future work. (C) 2006 Published by Elsevier B.V. C1 Stanford Univ, Ctr Study Language & Informat, Computat Learning Lab, Stanford, CA 94305 USA. Jozef Stefan Inst, Dept Intelligent Syst, SI-1000 Ljubljana, Slovenia. NASA, Ames Res Ctr, Ctr Computat Astrobiol & Fundamental Biol, Moffett Field, CA 94035 USA. RP Langley, P (reprint author), Stanford Univ, Ctr Study Language & Informat, Computat Learning Lab, Stanford, CA 94305 USA. EM langley@csli.stanford.edu NR 25 TC 12 Z9 12 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0933-3657 J9 ARTIF INTELL MED JI Artif. Intell. Med. PD JUL PY 2006 VL 37 IS 3 BP 191 EP 201 DI 10.1016/j.artmed.2006.04.003 PG 11 WC Computer Science, Artificial Intelligence; Engineering, Biomedical; Medical Informatics SC Computer Science; Engineering; Medical Informatics GA 063CB UT WOS:000238992500004 PM 16781850 ER PT J AU Wittenmyer, RA Endl, M Cochran, WD Hatzes, AP Walker, GAH Yang, SLS Paulson, DB AF Wittenmyer, Robert A. Endl, Michael Cochran, William D. Hatzes, Artie P. Walker, G. A. H. Yang, S. L. S. Paulson, Diane B. TI Detection limits from the Mcdonald Observatory planet search program SO ASTRONOMICAL JOURNAL LA English DT Article DE planetary systems; techniques : radial velocities ID EXTRA-SOLAR PLANETS; RADIAL-VELOCITY VARIABILITY; HOBBY-EBERLY TELESCOPE; MAIN-SEQUENCE STARS; NEPTUNE-MASS PLANET; TIME-SERIES; SUBSTELLAR COMPANIONS; ECHELLE SPECTROMETER; MAGNETIC ACTIVITY; ABSORPTION-LINES AB Based on the long-term radial velocity surveys carried out with the McDonald Observatory 2.7m Harlan J. Smith Telescope from 1988 to the present, we derive upper limits to long-period giant planet companions for 31 nearby stars. Data from three phases of the McDonald Observatory 2.7 m planet-search program have been merged together, and for 17 objects data from the pioneering Canada-France-Hawaii Telescope radial velocity program have also been included in the companion-limits determination. For those 17 objects, the baseline of observations is in excess of 23 yr, enabling the detection or exclusion of giant planets in orbits beyond 8 AU. We also consider the possibility of eccentric orbits in our computations. At an orbital separation of 5.2 AU, we can exclude on average planets of M sin i greater than or similar to (2.0 +/- 1.1) M-J (e = 0) and M sin i greater than or similar to (4.0 +/- 2.8) M-J (e = 0.6) for 25 of the 31 stars in this survey. However, we are not yet able to rule out "true Jupiters,'' i. e., planets of M sin i similar to 1M(J) in 5.2 AU orbits. These limits are of interest for the Space Interferometry Mission, Terrestrial Planet Finder, and Darwin missions, which will search for terrestrial planets orbiting nearby stars, many of which are included in this work. C1 Univ Texas, McDonald Observ, Austin, TX 78712 USA. Thuringer Landessternwarte Tautenburg, D-07778 Tautenburg, Germany. Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 3P6, Canada. NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Greenbelt, MD 20771 USA. RP Wittenmyer, RA (reprint author), Univ Texas, McDonald Observ, Austin, TX 78712 USA. EM robw@astro.as.utexas.edu; mike@astro.as.utexas.edu; wdc@shiraz.as.utexas.edu NR 67 TC 47 Z9 47 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 JUL PY 2006 VL 132 IS 1 BP 177 EP 188 DI 10.1086/504942 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 063XR UT WOS:000239053700014 ER PT J AU Deo, RP Crenshaw, DM Kraemer, SB AF Deo, R. P. Crenshaw, D. M. Kraemer, S. B. TI The host galaxies of narrow-line seyfert 1 galaxies: Nuclear dust morphology and starburst rings SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : nuclei; galaxies : Seyfert; galaxies : structure ID ACTIVE GALACTIC NUCLEI; BARRED GALAXIES; IMAGING SURVEY; DENSITY WAVES; CIRCUMNUCLEAR DUST; INACTIVE GALAXIES; DISK GALAXIES; GAS RESPONSE; BLACK-HOLES; BARS AB We present a study of the nuclear morphology of a sample of narrow- and broad-line Seyfert 1 galaxies (NLS1s and BLS1s, respectively) based on broadband images in the Hubble Space Telescope archives. In our previous study we found that large-scale stellar bars at > 1 kpc from the nucleus are more common in NLS1s than BLS1s. In this paper we find that NLS1s preferentially have grand-design dust spirals within similar to 1 kpc of their centers. We also find that NLS1s have a higher fraction of nuclear star-forming rings than BLS1s. We find that many of the morphological differences are due to the presence or absence of a large-scale stellar bar within the spiral host galaxy. In general, barred Seyfert 1 galaxies tend to have grand-design dust spirals at their centers, confirming the results of other researchers. The high fraction of grand-design nuclear dust spirals and stellar nuclear rings observed in NLS1s' host galaxies suggests a means for efficient fueling of their nuclei to support their high Eddington ratios. C1 Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Explorat Universe Div, Greenbelt, MD 20771 USA. RP Deo, RP (reprint author), Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. EM deo@chara.gsu.edu; crenshaw@chara.gsu.edu; stiskraemer@yancey.gsfc.nasa.gov NR 48 TC 51 Z9 51 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 JUL PY 2006 VL 132 IS 1 BP 321 EP 346 DI 10.1086/504894 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 063XR UT WOS:000239053700025 ER PT J AU Campana, S Tagliaferri, G Lazzati, D Chincarini, G Covino, S Page, K Romano, P Moretti, A Cusumano, G Mangano, V Mineo, T La Parola, V Giommi, P Perri, M Capalbi, M Zhang, B Barthelmy, S Cummings, J Sakamoto, T Burrows, DN Kennea, JA Nousek, JA Osborne, JP O'Brien, PT Godet, O Gehrels, N AF Campana, S Tagliaferri, G Lazzati, D Chincarini, G Covino, S Page, K Romano, P Moretti, A Cusumano, G Mangano, V Mineo, T La Parola, V Giommi, P Perri, M Capalbi, M Zhang, B Barthelmy, S Cummings, J Sakamoto, T Burrows, DN Kennea, JA Nousek, JA Osborne, JP O'Brien, PT Godet, O Gehrels, N TI The X-ray afterglow of the short gamma ray burst 050724 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma rays : bursts; X-rays : general ID TELESCOPE; GRB-050709; GALAXY; GRB; EMISSION; MISSION; ORIGIN; FLARES AB Short duration (<= 2 s) Gamma-ray bursts (GRBs) have been a mystery since their discovery. Until May 2005 very little was known about short GRBs, but this situation has changed rapidly in the last few months since the Swift and HETE-2 satellites have made it possible to discover X-ray and optical counterparts to these sources. Positional associations indicate that short GRBs arise in close-by galaxies (z < 0.7). Here we report on a detailed study of the short GRB 050724 X-ray afterglow. This burst shows strong flaring variability in the X-ray band. It clearly confirms early suggestions of X-ray activity in the 50-100 s time interval following the GRB onset seen with BATSE. Late flare activity is also observed. These observations support the idea that flares are related to the inner engine for short GRBs, as well as long GRBs. C1 Osserv Astron Brera, I-23807 Merate, LC, Italy. Univ Colorado, JILA, Boulder, CO 80309 USA. Univ Milan, Dipartimento Fis, I-20126 Milan, Italy. Univ Leicester, Dept Phys & Astron, Xray & Observat Astron Grp, Leicester LE1 7RH, Leics, England. Ist Astrofis Spaziale & Fis Cosm Palermo, INAF, I-90146 Palermo, Italy. ASI Sci Data Ctr, I-00044 Frascati, Roma, Italy. Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. RP Campana, S (reprint author), Osserv Astron Brera, Via Bianchi 46, I-23807 Merate, LC, Italy. EM sergio.campana@brera.inaf.it RI Barthelmy, Scott/D-2943-2012; Gehrels, Neil/D-2971-2012; OI Mineo, Teresa/0000-0002-4931-8445; giommi, paolo/0000-0002-2265-5003; Cusumano, Giancarlo/0000-0002-8151-1990; moretti, alberto/0000-0002-9770-0315; Perri, Matteo/0000-0003-3613-4409; La Parola, Valentina/0000-0002-8087-6488; Covino, Stefano/0000-0001-9078-5507; Tagliaferri, Gianpiero/0000-0003-0121-0723 NR 46 TC 67 Z9 68 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 JUL PY 2006 VL 454 IS 1 BP 113 EP 117 DI 10.1051/0004-6361:20064856 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 059IK UT WOS:000238726300015 ER PT J AU de Martino, D Matt, G Mukai, K Bonnet-Bidaud, JM Burwitz, V Gansicke, BT Haberl, F Mouchet, M AF de Martino, D Matt, G Mukai, K Bonnet-Bidaud, JM Burwitz, V Gansicke, BT Haberl, F Mouchet, M TI The X-ray properties of the magnetic cataclysmic variable UU Columbae SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : binaries : close; stars : individual : RXJ0512.2-3241 (UUCol); stars : novae, cataclysmic variables; X-rays : binaries; accretion, accretion disks ID SOFT INTERMEDIATE POLAR; WHITE-DWARFS; ACCRETION; EMISSION; MOMENTS AB Aims. XMM-Newton observations to determine for the first time the broad-band X-ray properties of the faint, high galactic latitude intermediate polar UUCol are presented. Methods. We performed X-ray timing analysis in different energy ranges of the EPIC cameras, which reveals the dominance of the 863 s white dwarf rotational period. The spin pulse is strongly energy dependent. Weak variabilities at the beat 935 s and at the 3.5 h orbital periods are also observed, but the orbital modulation is detected only below 0.5 keV. Simultaneous UV and optical photometry shows that the spin pulse is anti-phased with respect to the hard X-rays. Analysis of the EPIC and RGS spectra reveals the complexity of the X-ray emission, which is composed of a soft 50 eV black-body component and two optically thin emission components at 0.2 keV and 11 keV strongly absorbed by dense material with an equivalent hydrogen column density of 10(23) cm(-2) that partially (50%) covers the X-ray source. Results. The complex X-ray and UV/optical temporal behaviour indicates that accretion occurs predominantly (similar to 80%) via a disc with a partial contribution (similar to 20%) directly from the stream. The main accreting pole dominates at high energies whilst the secondary pole mainly contributes in the soft X-rays and at lower energies. The bolometric flux ratio of the soft-to-hard X-ray emissions is found to be consistent with the prediction of the standard accretion shock model. We find the white dwarf in UUCol accretes at a low rate and possesses a low magnetic moment. It is therefore unlikely that UUCol will evolve into a moderate field strength polar, so that the soft X-ray intermediate polars still remain an enigmatic small group of magnetic cataclysmic variables. C1 INAF Osserv Astron Capodimonte, I-80131 Naples, Italy. Univ Studi Roma Tre, Dipartimento Fis, I-00146 Rome, Italy. NASA, Goddard Space Flight Ctr, Lab High Energy Astrophys, Greenbelt, MD 20771 USA. CE Saclay, Serv Astrophys, DSM DAPNIA SAp, F-91191 Gif Sur Yvette, France. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. LUTH, Observ Paris, F-92195 Meudon, France. Univ Denis Diderot, UMR 7164, APC, F-75005 Paris, France. RP de Martino, D (reprint author), INAF Osserv Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy. EM demartino@na.astro.it; matt@fis.uniroma3.it; mukai@milkyway.gsfc.nasa.gov; bonnetbidaud@cea.fr; burwitz@mpe.mpg.de; boris.gaensicke@warwick.ac.uk; fwh@mpe.mpg.de; martine.mouchet@obspm.fr RI Gaensicke, Boris/A-9421-2012; OI Gaensicke, Boris/0000-0002-2761-3005; Haberl, Frank/0000-0002-0107-5237; de Martino, Domitilla/0000-0002-5069-4202 NR 28 TC 17 Z9 17 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 JUL PY 2006 VL 454 IS 1 BP 287 EP 294 DI 10.1051/0004-6361:20065078 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 059IK UT WOS:000238726300034 ER PT J AU Menten, KM Reid, MJ Krugel, E Claussen, MJ Sahai, R AF Menten, KM Reid, MJ Krugel, E Claussen, MJ Sahai, R TI Radio continuum monitoring of the extreme carbon star IRC+10216 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : carbon; stars : AGB and post-AGB; radio continuum : stars; techniques : interferometic ID PERIOD VARIABLE-STARS; CIRCUMSTELLAR ENVELOPES; SUBMILLIMETER ARRAY; DUST SHELL; PHOTOSPHERES; EMISSION; CO AB We describe Very Large Array observations of the extreme carbon star IRC+10216 at 8.4, 14.9, and 22.5 GHz made over a two year period. We find possible variability correlated with the infrared phase and a cm- to sub-millimeter wavelength spectral index very close to 2. The variability, observed flux densities, and upper limit on the size are consistent with the emission arising from the stellar photosphere or a slightly larger radio photosphere. C1 Max Planck Inst Radioastron, D-53121 Bonn, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02139 USA. Natl Radio Astron Observ, Array Operat Ctr, Socorro, NM 87801 USA. Jet Prop Lab, Pasadena, CA 91109 USA. RP Menten, KM (reprint author), Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany. EM kmenten@mpifr-bonn.mpg.de; reid@cfa.harvard.edu; p309ekr@mpifr-bonn.mpg.de; mclausse@nrao.edu; raghvendra.sahai@jpl.nasa.gov NR 28 TC 12 Z9 12 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 JUL PY 2006 VL 453 IS 1 BP 301 EP 307 DI 10.1051/0004-6361:20054463 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 051US UT WOS:000238187700033 ER PT J AU Miceli, M Decourchelle, A Ballet, J Bocchino, F Hughes, JP Hwang, U Petre, R AF Miceli, M Decourchelle, A Ballet, J Bocchino, F Hughes, JP Hwang, U Petre, R TI The X-ray emission of the supernova remnant W49B observed with XMM-Newton SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE X-rays : ISM; ISM : supernova remnants; ISM : individual object : W49B ID 25 APRIL 1998; CASSIOPEIA-A; CONTINUUM; EXPLOSIONS; ABSORPTION; ABUNDANCES; SPECTRA; RADIO; BURST; ASCA AB Context. In the framework of the study of supernova remnants and their complex interaction with the interstellar medium, we report on an XMM-Newton EPIC observation of the Galactic supernova remnant W49B. Aims. We investigated the spatial distribution of the chemical and physical properties of the plasma, so as to get important constraints on the physical scenario, on the dynamics of the supernova explosion, and on the interaction of the supernova remnant with the ambient interstellar clouds. Methods. We present line images, equivalent width maps, and a spatially resolved spectral analysis of a set of homogeneous regions. Results. The X-ray spectrum of W49B is characterized by strong K emission lines from Si, S, Ar, Ca, and Fe. In all the regions studied, the X-ray spectrum is dominated by the emission from the ejecta and there is no indication of radial stratification of the elements. A high overabundance of Ni (Ni/Ni-circle dot = 10(-1)(+2)) is required in the bright central region and the previous detection of Cr and Mn line emission is confirmed. Spectra are described well by two thermal components in collisional ionization equilibrium. We observe spatial variations in the temperature, with the highest temperature found in the east and the lowest in the west. Conclusions. Our results support a scenario in which the X-ray emission comes from ejecta interacting with a dense belt of ambient material, but another possibility is that the remnant is the result of an asymmetric bipolar explosion with the eastern jet being hotter and more Fe-rich than the western jet. The eastern jet is confined by interaction with ambient molecular clouds. Comparison of the observed abundances with yields for hypernova and supernova nucleosynthesis does not directly support the association of W49B with gamma-ray burst, although it remains possible. C1 CEA Saclay, DSM DAPNIA, Serv Astrophys, AIM,UMR 7158, F-91191 Gif Sur Yvette, France. Univ Palermo, Dipartimento Sci Fisiche & Astron, Sez Astron, I-90134 Palermo, Italy. Osserv Astron Padova, INAF, I-90134 Palermo, Italy. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA. Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Miceli, M (reprint author), CEA Saclay, DSM DAPNIA, Serv Astrophys, AIM,UMR 7158, F-91191 Gif Sur Yvette, France. EM miceli@astropa.unipa.it OI Miceli, Marco/0000-0003-0876-8391; Bocchino, Fabrizio/0000-0002-2321-5616 NR 30 TC 42 Z9 42 U1 0 U2 3 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 JUL PY 2006 VL 453 IS 2 BP 567 EP 578 DI 10.1051/0004-6361:20054290 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053RL UT WOS:000238322500020 ER PT J AU Miller, L Turner, TJ Reeves, JN George, IM Porquet, D Nandra, K Dovciak, M AF Miller, L Turner, TJ Reeves, JN George, IM Porquet, D Nandra, K Dovciak, M TI Variable iron-line emission near the black hole of Markarian 766 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE accretion, accretion disks; galaxies : active; X-rays : individuals : Mrk 766 ID X-RAY REFLECTION; XMM-NEWTON; GALAXY MCG-6-30-15; COLD MATTER; SPECTRA; MRK-766; NUCLEI; DISK AB Aims. We investigate the link between ionised Fe X-ray line emission and continuum emission in a bright nearby AGN, Mrk 766. Methods. A new long (433 ks) XMM-Newton observation is analysed, together with archival data from 2000 and 2001. The contribution from ionised line emission is measured and its time variations on short (5-20 ks) timescales are correlated with the continuum emission. Results. The ionised line flux is found to be highly variable and to be strongly correlated with the continuum flux, demonstrating an origin for the ionised line emission that is co-located with the continuum emission. Most likely the emission is ionised reflection from the accretion disc within a few A. U. of the central black hole, and its detection marks the first time that such an origin has been identified other than by fitting to spectral line profiles. Future observations may be able to measure a time lag and hence achieve reverberation mapping of AGN at X-ray energies. C1 Univ Oxford, Dept Phys, Oxford OX1 3RH, England. Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Explorat Universe Div, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. Imperial Coll Sch Med, Blackett Lab, Astrophys Grp, London SW7 2AW, England. Acad Sci Czech Republ, Astron Inst, Prague 14131, Czech Republic. RP Miller, L (reprint author), Univ Oxford, Dept Phys, Denys Wilkinson Bldg,Keble Rd, Oxford OX1 3RH, England. EM lam@astro.ox.ac.uk RI Dovciak, Michal/F-4258-2014; OI Dovciak, Michal/0000-0003-0079-1239; Porquet, Delphine/0000-0001-9731-0352 NR 20 TC 21 Z9 21 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 JUL PY 2006 VL 453 IS 1 BP L13 EP L16 DI 10.1051/0004-6361:20065276 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 051US UT WOS:000238187700004 ER PT J AU Holder, J Atkins, RW Badran, HM Blaylock, G Bradbury, SM Buckley, JH Byrum, KL Carter-Lewis, DA Celik, O Chow, YCK Cogan, P Cui, W Daniel, MK Perez, ID Dowdall, C Dowkontt, P Duke, C Falcone, AD Fegan, SJ Finley, JP Fortin, P Fortson, LF Gibbs, K Gillanders, G Glidewell, OJ Grube, J Gutierrez, KJ Gyuk, G Hall, J Hanna, D Hays, E Horan, D Hughes, SB Humensky, TB Imran, A Jung, I Kaaret, P Kenny, GE Kieda, D Kildea, J Knapp, J Krawczynski, H Krennrich, F Lang, MJ LeBohec, S Linton, E Little, EK Maier, G Manseri, H Milovanovic, A Moriarty, P Mukherjee, R Ogden, PA Ong, RA Petry, D Perkins, JS Pizlo, F Pohl, M Quinn, J Ragan, K Reynolds, PT Roache, ET Rose, HJ Schroedter, M Sembroski, GH Sleege, G Steele, D Swordy, SP Syson, A Toner, JA Valcarcel, L Vassiliev, VV Wakely, SP Weekes, TC White, RJ Williams, DA Wagner, R AF Holder, J. Atkins, R. W. Badran, H. M. Blaylock, G. Bradbury, S. M. Buckley, J. H. Byrum, K. L. Carter-Lewis, D. A. Celik, O. Chow, Y. C. K. Cogan, P. Cui, W. Daniel, M. K. Perez, I. de la Calle Dowdall, C. Dowkontt, P. Duke, C. Falcone, A. D. Fegan, S. J. Finley, J. P. Fortin, P. Fortson, L. F. Gibbs, K. Gillanders, G. Glidewell, O. J. Grube, J. Gutierrez, K. J. Gyuk, G. Hall, J. Hanna, D. Hays, E. Horan, D. Hughes, S. B. Humensky, T. B. Imran, A. Jung, I. Kaaret, P. Kenny, G. E. Kieda, D. Kildea, J. Knapp, J. Krawczynski, H. Krennrich, F. Lang, M. J. LeBohec, S. Linton, E. Little, E. K. Maier, G. Manseri, H. Milovanovic, A. Moriarty, P. Mukherjee, R. Ogden, P. A. Ong, R. A. Petry, D. Perkins, J. S. Pizlo, F. Pohl, M. Quinn, J. Ragan, K. Reynolds, P. T. Roache, E. T. Rose, H. J. Schroedter, M. Sembroski, G. H. Sleege, G. Steele, D. Swordy, S. P. Syson, A. Toner, J. A. Valcarcel, L. Vassiliev, V. V. Wakely, S. P. Weekes, T. C. White, R. J. Williams, D. A. Wagner, R. TI The first VERITAS telescope SO ASTROPARTICLE PHYSICS LA English DT Article DE gamma ray astronomy; Cherenkov telescopes ID TEV GAMMA-RAYS; ATMOSPHERIC CHERENKOV TELESCOPE; CRAB-NEBULA; IMAGING TECHNIQUE; SYSTEM; SPECTRUM; PROJECT AB The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic Radiation Imaging Telescope Array System) has been in operation since February 2005. We present here a technical description of the instrument and a summary of its performance. The calibration methods are described, along with the results of Monte Carlo simulations of the telescope and comparisons between real and simulated data. The analysis of TeV gamma-ray observations of the Crab Nebula, including the reconstructed energy spectrum, is shown to give results consistent with earlier measurements. The telescope is operating as expected and has met or exceeded all design specifications. (c) 2006 Elsevier B.V. All rights reserved. C1 Univ Leeds, Sch Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. Univ Utah, Dept Phys, Salt Lake City, UT 84112 USA. Tanta Univ, Fac Sci, Dept Phys, Tanta 31527, Egypt. Univ Massachusetts, Dept Phys, Amherst, MA 01003 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Univ Coll Dublin, Sch Phys, Dublin 4, Ireland. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. Univ Oxford, Dept Phys, Oxford OX1 3RH, England. Grinnell Coll, Dept Phys, Grinnell, IA 50112 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Columbia Univ Barnard Coll, Dept Phys & Astron, New York, NY 10027 USA. Adler Planetarium & Astron Museum, Dept Astron, Chicago, IL 60605 USA. Harvard Smithsonian Ctr Astrophys, Fred Lawrence Whipple Observ, Amado, AZ 85645 USA. McGill Univ, Dept Phys, Galway, Ireland. McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Van Allen Hall, Dept Phys & Astron, Iowa City, IA 52242 USA. Galway Mayo Inst Technol, Dept Phys & Life Sci, Galway, Ireland. Cork Inst Technol, Dept Appl Phys & Instrumentat, Cork, Ireland. Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA. Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Holder, J (reprint author), Univ Leeds, Sch Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. EM jh@ast.leeds.ac.uk RI Hays, Elizabeth/D-3257-2012; Hall, Jeter/E-9294-2015; Daniel, Michael/A-2903-2010; OI Daniel, Michael/0000-0002-8053-7910; Cui, Wei/0000-0002-6324-5772; Knapp, Johannes/0000-0003-1519-1383; Lang, Mark/0000-0003-4641-4201 NR 31 TC 118 Z9 118 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-6505 J9 ASTROPART PHYS JI Astropart Phys. PD JUL PY 2006 VL 25 IS 6 BP 391 EP 401 DI 10.1016/j.astropartphys.2006.04.002 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 063BQ UT WOS:000238991300006 ER PT J AU Yang, Y Mushotzky, RF Barger, AJ Cowie, LL AF Yang, Y. Mushotzky, R. F. Barger, A. J. Cowie, L. L. TI Spatial correlation function of the Chandra-selected active galactic nuclei SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; galaxies : nuclei; large-scale structure of universe; X-rays : diffuse background ID QSO REDSHIFT SURVEY; X-RAY SURVEY; SUPERMASSIVE BLACK-HOLES; LARGE-SCALE STRUCTURE; LYMAN-BREAK GALAXIES; DARK-MATTER HALOES; DEEP FIELD SOUTH; SOURCE CATALOG; HOST GALAXIES; LUMINOSITY AB We present the spatial correlation function of nonstellar X-ray point sources in the 0.4 deg(-2) Chandra Large Area Synoptic X-Ray Survey (CLASXS) using 233 spectroscopically identified sources. We supplement our analysis with 252 sources with redshifts from the Chandra Deep Field-North (CDF-N), allowing correlation functions that have been estimated over comoving scales of a few to a few hundred Mpc. We calculate both redshift-space and projected correlation functions, averaged over the redshift range of 0.1 < z < 3.0, for both CLASXS and CDF-N fields. The correlation functions can be described well with a power law in the form xi(s) = (s/s(0))(-gamma), with gamma = 1.6(-0.3)(+0.4) and s(0) = 8.0(-1.5)(+1.4) Mpc for the CLASXS field and s(0) = 8.55(-0.74)(+0.75) Mpc and gamma = 1.3 +/- 0.1 for the CDF-N field. The real-space correlation functions derived from the projected correlation functions are found to be r(0) = 8.1(-2.2)(+1.2) Mpc and gamma = 2.1 +/- 0.5 for the CLASXS field and r(0) = 5.8(-1.5)(+1.0) Mpc and gamma = 1.38(-0.14)(+0.12) for the CDF-N field. By comparing the real- and redshift-space correlation functions in the combined CLASXS and CDFN samples, we are able to estimate the redshift distortion parameter beta = 0.4 +/- 0.2 at an effective redshift z = 0.94. We find a weak correlation between X-ray luminosity and clustering amplitude. We study the evolution of the AGN clustering by dividing the samples into four redshift bins over 0.1 Mpc < z < 3.0 Mpc. We find a mild evolution in the clustering amplitude, corresponding to a rapid increase of bias with redshift [b(z = 0.45) = 0.95 +/- 0.15 and b(z = 2.07) = 3.03 +/- 0.83], similar to that found in optically selected quasars. The average halo mass is found to be log (M-halo/M-circle dot) similar to 12.1. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20770 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. RP Yang, Y (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NR 62 TC 46 Z9 46 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 JUL 1 PY 2006 VL 645 IS 1 BP 68 EP 82 DI 10.1086/502706 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 060WQ UT WOS:000238832900005 ER PT J AU Bendo, GJ Buckalew, BA Dale, DA Draine, BT Joseph, RD Kennicutt, RC Sheth, K Smith, JDT Walter, F Calzetti, D Cannon, JM Engelbracht, CW Gordon, KD Helou, G Hollenbach, D Murphy, EJ Roussel, H AF Bendo, George J. Buckalew, Brent A. Dale, Daniel A. Draine, Bruce T. Joseph, Robert D. Kennicutt, Robert C., Jr. Sheth, Kartik Smith, John-David T. Walter, Fabian Calzetti, Daniela Cannon, John M. Engelbracht, Charles W. Gordon, Karl D. Helou, George Hollenbach, David Murphy, Eric J. Roussel, Helene TI Spitzer and JCMT observations of the active galactic nucleus in the Sombrero Galaxy (NGC 4594) SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 4594); galaxies : ISM; galaxies : nuclei; infrared : galaxies ID BRIGHT SPIRAL GALAXIES; MULTIBAND IMAGING PHOTOMETER; CLERK-MAXWELL-TELESCOPE; SPACE-TELESCOPE; STELLAR POPULATIONS; INFRARED-EMISSION; SEYFERT-GALAXIES; NEARBY GALAXIES; STAR-FORMATION; IRAS GALAXIES AB We present Spitzer 3.6-160 mu m images, Spitzer mid-infrared spectra, and JCMT SCUBA 850 mu m images of the Sombrero Galaxy ( NGC 4594), an Sa galaxy with a 10(9) M-circle dot low-luminosity active galactic nucleus ( AGN). The brightest infrared sources in the galaxy are the nucleus and the dust ring. The spectral energy distribution of the AGN demonstrates that, while the environment around the AGN is a prominent source of mid- infrared emission, it is a relatively weak source of far-infrared emission, as had been inferred for AGNs in previous research. The weak nuclear 160 mu m emission and the negligible polycyclic aromatic hydrocarbon emission from the nucleus also implies that the nucleus is a site of only weak star formation activity and the nucleus contains relatively little cool interstellar gas needed to fuel such activity. We propose that this galaxy may be representative of a subset of low-ionization nuclear emission region galaxies that are in a quiescent AGN phase because of the lack of gas needed to fuel circumnuclear star formation and Seyfert-like AGN activity. Surprisingly, the AGN is the predominant source of 850 mu m emission. We examine the possible emission mechanisms that could give rise to the 850 mu m emission and find that neither thermal dust emission, CO line emission, bremsstrahlung emission, nor the synchrotron emission observed at radio wavelengths can adequately explain the measured 850 mu m flux density by themselves. The remaining possibilities for the source of the 850 mu m emission include a combination of known emission mechanisms, synchrotron emission that is self-absorbed at wavelengths longer than 850 mu m, or unidentified spectral lines in the 850 mu m band. C1 Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, London SW7 2AZ, England. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. CALTECH, Pasadena, CA 91101 USA. Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. Univ Hawaii, Astron Inst, Honolulu, HI 96822 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Max Planck Inst Astron, D-69117 Heidelberg, Germany. Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Yale Univ, Dept Astron, New Haven, CT 06520 USA. RP Bendo, GJ (reprint author), Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, Prince Consort Rd, London SW7 2AZ, England. EM g.bendo@imperial.ac.uk OI Draine, Bruce/0000-0002-0846-936X NR 72 TC 40 Z9 40 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 JUL 1 PY 2006 VL 645 IS 1 BP 134 EP 147 DI 10.1086/504033 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 060WQ UT WOS:000238832900009 ER PT J AU Isobe, N Makishima, K Tashiro, M Itoh, K Iyomoto, N Takahashi, I Kaneda, H AF Isobe, N. Makishima, K. Tashiro, M. Itoh, K. Iyomoto, N. Takahashi, I. Kaneda, H. TI The XMM-Newton examination of energetics in the east lobe of the nearby radio galaxy Fornax A (NGC 1316) SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (Fornax A); magnetic fields; radiation mechanisms : nonthermal; radio continuum : galaxies; X-rays : galaxies ID X-RAY-EMISSION; MAGNETIC-FIELD STRENGTHS; ACTIVE GALACTIC NUCLEI; HOT-SPOTS; 408 MHZ; CHANDRA; SCALE; ASCA AB An XMM-Newton observation of the east radio lobe of the nearby radio galaxy Fornax A is reported. The diffuse hard X-ray emission associated with the east lobe, which was initially discovered by ASCA and ROSAT, is confirmed with significant signal statistics, after strictly removing 59 sources detected within the MOS field of view. Its X-ray spectrum is described by a single power-law model, which is absorbed by a medium with a column density consistent with that toward the object. The best-fit X-ray photon index, Gamma(X) = 1.62(-0.15)(+0.24), agrees with the synchrotron radio index, Gamma(R) = 1.68 +/- 0.1, determined from the radio spectrum between 29.9 MHz and 5 GHz. Hence, the inverse Compton interpretation for the diffuse X-rays is justified. The X-ray flux density in the east lobe is measured to be 90 +/- 21 nJy at 1 keV (including both statistical and systematic errors) with the index fixed at the radio value. This gives electron and magnetic energy densities of 3.0(-1.0)(+1.5) x 10(-13) and 6.1(-3.5)(+5.7) x 10(-14) ergs cm(-3), respectively. The latter corresponds to a magnetic field strength of 1.24(-0.40)(+0.50) mu G, which is smaller than the field estimated under the minimum energy condition, 1.55 mu G, although with a slightly large error. Reevaluation is also made of the ASCA result on the west lobe, to show that both lobes share a similar physical condition in terms of energetics. C1 RIKEN, Inst Phys & Chem Res, Cosm Radiat Lab, Wako, Saitama 3510198, Japan. Univ Tokyo, Dept Phys, Tokyo 1130033, Japan. Saitama Univ, Dept Phys, Shimo Okubo, Saitama 3388570, Japan. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Japan Aerosp Explorat Agcy, ISAS, JAXA, Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. RP Isobe, N (reprint author), RIKEN, Inst Phys & Chem Res, Cosm Radiat Lab, 2-1 Hirosawa, Wako, Saitama 3510198, Japan. RI Tashiro, Makoto/J-4562-2012 NR 38 TC 22 Z9 22 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 JUL 1 PY 2006 VL 645 IS 1 BP 256 EP 263 DI 10.1086/504253 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 060WQ UT WOS:000238832900019 ER PT J AU Abbas, MM Tankosic, D Craven, PD Spann, JF LeClair, A West, EA Weingartner, JC Tielens, AGGM Nuth, JA Camata, RP Gerakines, PA AF Abbas, M. M. Tankosic, D. Craven, P. D. Spann, J. F. LeClair, A. West, E. A. Weingartner, J. C. Tielens, A. G. G. M. Nuth, J. A. Camata, R. P. Gerakines, P. A. TI Photoelectric emission measurements on the analogs of individual cosmic dust grains SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust; extinction ID ELECTROSTATIC CHARGING PROPERTIES; INTERSTELLAR DUST; IONIZATION-POTENTIALS; SILVER PARTICLES; METAL-CLUSTERS; LUNAR DUST; ENERGY; PHOTOEMISSION; YIELD; GAS AB The photoelectric emission process is considered to be the dominant mechanism for charging of cosmic dust grains in many astrophysical environments. The grain charge and equilibrium potentials play an important role in the dynamical and physical processes that include heating of the neutral gas in the interstellar medium, coagulation processes in the dust clouds, and levitation and dynamical processes in the interplanetary medium and planetary surfaces and rings. An accurate evaluation of photoelectric emission processes requires knowledge of the photoelectric yields of individual dust grains of astrophysical composition as opposed to the values obtained from measurements on flat surfaces of bulk materials, as it is generally assumed on theoretical considerations that the yields for the small grains are much different from the bulk values. We present laboratory measurements of the photoelectric yields of individual dust grains of silica, olivine, and graphite of similar to 0.09-5 mu m radii levitated in an electrodynamic balance and illuminated with UV radiation at 120 - 160 nm wavelengths. The measured yields are found to be substantially higher than the bulk values given in the literature and indicate a size dependence with larger particles having order-of-magnitude higher values than for submicron-size grains. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Huntsville, AL 35899 USA. George Mason Univ, Fairfax, VA 22030 USA. Univ Groningen, Kapteyn Astron Inst, Groningen, Netherlands. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Alabama, Dept Phys, Birmingham, AL 35294 USA. RP Abbas, MM (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM mian.m.abbas@nasa.gov; tankosd@uah.edu; paul.d.craven@nasa.gov; james.f.spann@nasa.gov; andre.leclair@msfc.nasa.gov; edward.a.west@nasa.gov; joe@physics.gmu.edu; tielens@astro.rug.nl; joseph.a.nuth@nasa.gov; camata@uab.edu; gerakines@uab.edu RI Gerakines, Perry/B-9705-2009; Gerakines, Perry/D-2226-2012; Nuth, Joseph/E-7085-2012 OI Gerakines, Perry/0000-0002-9667-5904; NR 49 TC 24 Z9 24 U1 0 U2 7 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 JUL 1 PY 2006 VL 645 IS 1 BP 324 EP 336 DI 10.1086/504281 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 060WQ UT WOS:000238832900027 ER PT J AU Mastichiadis, A Kazanas, D AF Mastichiadis, A. Kazanas, D. TI The supercritical pile model for gamma-ray bursts: Spectro-temporal properties SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; radiation mechanisms : nonthermal; relativity ID ACTIVE GALACTIC NUCLEI; 28 FEBRUARY 1997; F-NU PEAK; HIGH-ENERGY; COMPTON-SCATTERING; PAIR PRODUCTION; EMISSION; RADIATION; SPECTRA; BATSE AB We present the spectral and temporal radiative signatures expected within the "supercritical pile" model of gamma-ray bursts (GRBs). This model is motivated by the need for a process that provides the dissipation necessary in GRBs and presents a well-defined scheme for converting the energy stored in the relativistic protons of the relativistic blast waves (RBWs) associated with GRBs into radiation; at the same time, it leads to spectra that exhibit a peak in the burst nu F(nu) distribution at an energy E(peak) similar or equal to 1 MeV in the observer's frame, in agreement with observations and largely independent of the Lorentz factor Gamma of the associated relativistic outflow. Furthermore, this scheme does not require (but does not preclude) acceleration of particles at the shock other than that provided by the isotropization of the flow bulk kinetic energy in the RBW frame. In the present paper we model in detail the evolution of protons, electrons, and photons from a RBW to produce detailed spectra of the prompt GRB phase as a function of time from across a very broad range in frequency, spanning roughly 4 log Gamma decades. The model spectra are in general agreement with observations and provide a means for delineating the model parameters through direct comparison with trends observed in GRB properties. C1 Univ Athens, Dept Phys, GR-15783 Zografos, Greece. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Mastichiadis, A (reprint author), Univ Athens, Dept Phys, GR-15783 Zografos, Greece. NR 44 TC 16 Z9 16 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 JUL 1 PY 2006 VL 645 IS 1 BP 416 EP 430 DI 10.1086/500574 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 060WQ UT WOS:000238832900034 ER PT J AU Grupe, D Brown, PJ Cummings, J Zhang, B Retter, A Burrows, DN Boyd, PT Capalbi, M Gehrels, N Holland, ST Meszaros, P Nousek, JA Kennea, JA O'Brien, P Osborne, J Pagani, C Racusin, JL Roming, P Schady, P AF Grupe, Dirk Brown, Peter J. Cummings, Jay Zhang, Bing Retter, Alon Burrows, David N. Boyd, Patricia T. Capalbi, Milvia Gehrels, Neil Holland, Stephen T. Meszaros, Peter Nousek, John A. Kennea, Jamie A. O'Brien, Paul Osborne, Julian Pagani, Claudio Racusin, Judith L. Roming, Peter Schady, Patricia TI Swift observations of GRB 050603: An afterglow with a steep late-time decay slope SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID GAMMA-RAY BURSTS; LIGHT CURVES; TELESCOPE; ENERGETICS; EMISSION; SPECTRA; MISSION; JETS AB We report the results of Swift observations of the gamma-ray burst GRB 050603. With a V magnitude V 18: 2 about 10 hr after the burst, the optical afterglow was the brightest thus far detected by Swift and one of the brightest optical afterglows ever seen. The Burst Alert Telescope ( BAT) light curves show three fast-rise exponential-decay spikes with T-90 = 12 s and a fluence of 7.6 x 10(-6) ergs cm(-2) in the 15-150 keV band. With E-gamma,E-iso = 1.26 x 10(54) ergs, it was also one of the most energetic bursts of all times. The Swift spacecraft began observation of the afterglow with the narrow-field instruments about 10 hr after the detection of the burst. The burst was bright enough to be detected by the Swift UV/Optical telescope ( UVOT) for almost 3 days and by the X-Ray Telescope ( XRT) for a week after the burst. The X-ray light curve shows a rapidly fading afterglow with a decay index alpha = 1.76(-0.07)(+0.15). The X-ray energy spectral index was beta(X) = 0.71 +/- 0.10 with the column density in agreement with the Galactic value. The spectral analysis does not show an obvious change in the X-ray spectral slope over time. The optical UVOT light curve decays with a slope of alpha = 1.8 +/- 0.2. The steepness and the similarity of the optical and X-ray decay rates suggest that the afterglow was observed after the jet break. We estimate a jet opening angle of about 1 degrees-2 degrees. C1 Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. ASI Sci Data Ctr, I-00044 Frascati, Italy. Univ Space Res Assoc, Seabrook, MD 20706 USA. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7R, Leics, England. Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. RP Grupe, D (reprint author), Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. RI Boyd, Patricia/D-3274-2012; Gehrels, Neil/D-2971-2012; Racusin, Judith/D-2935-2012 NR 48 TC 16 Z9 16 U1 1 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 JUL 1 PY 2006 VL 645 IS 1 BP 464 EP 469 DI 10.1086/504315 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 060WQ UT WOS:000238832900038 ER PT J AU Ding, GQ Zhang, SN Li, TP Qu, JL AF Ding, G. Q. Zhang, S. N. Li, T. P. Qu, J. L. TI Evolution of hard X-ray spectra along the orbital phase in circinus X-1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : general; stars : individual (Circinus X-1); X-rays : binaries; X-rays : general; X-rays : individual (Circinus X-1) ID BROAD-BAND SPECTRUM; CIR X-1; MODEL; TAIL; ACCRETION; SUPERNOVA; DISCOVERY; BRANCHES; BURSTS AB Using the data from the Proportional Counter Array and the High-Energy X-Ray Timing Experiment on board the Rossi X-Ray Timing Explorer satellite, we investigate the evolution of the 3-200 keV spectrum of the peculiar low-mass X-ray binary Circinus X-1 along its orbital phase. A power-law hard component, dominating above similar to 30 keVas well as contributing between 0.9% and 3.5% of the total flux, and the iron emission line are detected in the spectrum. It is found that the derived photon index (Gamma) of the power-law hard component and the characteristics of the iron emission line are modulated by the orbital phase: the hardest hard tail, the lowest line energy, and the largest line width of the iron emission line are detected at the periastron. However, the softest hard tail, the highest line energy, and the lowest line width of the iron emission line are detected after the apastron. At the periastron the source evolves along a complete track in the color-color diagram. These behaviors of orbital modulation are discussed. A possible origin of the power-law hard component is also discussed. 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, Key Lab Particle Astrophys, Beijing 100049, Peoples R China. RP Ding, GQ (reprint author), Tsinghua Univ, Dept Phys, Beijing 100084, Peoples R China. EM dinggq@mail.tsinghua.edu.cn; zhangsn@mail.tsinghuaedu.cn; litp@mail.tsinghua.edu.cn; qujl@mail.ihep.ac.cn NR 37 TC 6 Z9 6 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 JUL 1 PY 2006 VL 645 IS 1 BP 576 EP 588 DI 10.1086/504308 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 060WQ UT WOS:000238832900047 ER PT J AU Birn, J Forbes, TG Hesse, M AF Birn, Joachim Forbes, Terry G. Hesse, Michael TI Stability and dynamic evolution of three-dimensional flux ropes SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; sun : corona; sun : magnetic fields ID CORONAL MASS EJECTIONS; SOLAR-FLARES; MAGNETIC CONFIGURATIONS; DRIVEN EVOLUTION; KINK INSTABILITY; ENERGY BUILDUP; MODEL; EQUILIBRIUM; LOOP; RECONNECTION AB A crucial problem in the study of coronal mass ejections (CMEs) and solar flares is the identification of initial configurations and boundary conditions that can produce an eruption of the field configuration. In this paper we use ( ideal) magnetohydrodynamic (MHD) simulations to investigate the stability and dynamic evolution of two ( approximate) equilibrium configurations. The initial models investigated are derived within a general framework for the construction of series of suitable coronal states. They consist of twisted flux ropes, connected to the photosphere and anchored in the corona by an overlying arcade, embedded in a helmet streamer type configuration. The two models studied differ by the magnitude of the toroidal field and, correspondingly, the degree of twist and the amount of plasma pressure. The model with the least twist remains stable and settles into an equilibrium that differs only slightly from the initial state. In contrast, the more strongly twisted flux rope becomes unstable. Some portion of it breaks out in a kinklike fashion and moves rapidly outward, while another portion remains below. The evolved stage is characterized by the formation of a thin current sheet below an outward-moving rope. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ New Hampshire, Durham, NH 03824 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Birn, J (reprint author), Los Alamos Natl Lab, MS D466, Los Alamos, NM 87545 USA. EM jbirn@lanl.gov; terry.forbes@unh.edu; hesse@gsfc.nasa.gov RI Hesse, Michael/D-2031-2012; NASA MMS, Science Team/J-5393-2013 OI NASA MMS, Science Team/0000-0002-9504-5214 NR 42 TC 23 Z9 23 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 JUL 1 PY 2006 VL 645 IS 1 BP 732 EP 741 DI 10.1086/504280 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 060WQ UT WOS:000238832900061 ER PT J AU Arras, P Blaes, O Turner, NJ AF Arras, Phil Blaes, Omer Turner, Neal J. TI Quasi-periodic oscillations from magnetorotational turbulence SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; MHD; turbulence; waves; X-rays : binaries ID 3-DIMENSIONAL MAGNETOHYDRODYNAMIC SIMULATIONS; BLACK-HOLE ACCRETION; DISKS; RESONANCE AB Quasi-periodic oscillations (QPOs) in the X-ray light curves of accreting neutron star and black hole binaries have been widely interpreted as being due to standing wave modes in accretion disks. These disks are thought to be highly turbulent due to the magnetorotational instability (MRI). We study wave excitation by MRI turbulence in the shearing box geometry. We demonstrate that axisymmetric acoustic modes and radial epicyclic motions driven by MRI turbulence give rise to narrow, distinct peaks in the temporal power spectrum. Inertial waves, on the other hand, do not give rise to distinct peaks which rise significantly above the continuum noise spectrum set by MRI turbulence, even when the fluid motions are projected onto the eigenfunctions of the modes. This is a serious problem for QPO models based on inertial waves. C1 Univ Calif Santa Barbara, Kavli Inst Theoret Phys, Santa Barbara, CA 93106 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Arras, P (reprint author), Univ Calif Santa Barbara, Kavli Inst Theoret Phys, Kohn Hall, Santa Barbara, CA 93106 USA. EM arras@kitp.ucsb.edu; blaes@physics.ucsb.edu; neal.turner@nasa.jpl.gov OI Turner, Neal/0000-0001-8292-1943 NR 20 TC 24 Z9 24 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 JUL 1 PY 2006 VL 645 IS 1 BP L65 EP L68 DI 10.1086/505966 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 060WS UT WOS:000238833100017 ER PT J AU Millan-Gabet, R Monnier, JD Berger, JP Traub, WA Schloerb, FP Pedretti, E Benisty, M Carleton, NP Haguenauer, P Kern, P Labeye, P Lacasse, MG Malbet, F Perraut, K Pearlman, M Thureau, N AF Millan-Gabet, R. Monnier, J. D. Berger, J. -P. Traub, W. A. Schloerb, F. P. Pedretti, E. Benisty, M. Carleton, N. P. Haguenauer, P. Kern, P. Labeye, P. Lacasse, M. G. Malbet, F. Perraut, K. Pearlman, M. Thureau, N. TI Bright localized near-infrared emission at 1-4 AU in the AB Aurigae disk revealed by IOTA closure phases SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; instrumentation : interferometers; planetary systems : protoplanetary disks; stars : formation; stars : individual (AB Aurigae); techniques : high angular resolution ID HERBIG AE/BE STARS; T-TAURI STARS; YOUNG STELLAR OBJECTS; CIRCUMSTELLAR STRUCTURE; INTERFEROMETER; ACCRETION; DISTRIBUTIONS AB We report on the detection of localized off-center emission at 1-4 AU in the circumstellar environment of the young stellar object AB Aurigae. We used closure-phase measurements in the near-infrared that were made at the long-baseline interferometer IOTA, the first obtained on a young stellar object using this technique. When probing sub-AU scales, all closure phases are close to zero degrees, as expected given the previously determined size of the AB Aurigae inner-dust disk. However, a clear closure-phase signal of -3 .degrees 5 +/- 0.degrees 5 is detected on one triangle containing relatively short baselines, requiring a high degree of non-point symmetry from emission at larger (AU-sized) scales in the disk. We have not identified any alternative explanation for these closure-phase results, and we demonstrate that a "disk hot spot" model can fit our data. We speculate that such detected asymmetric near-infrared emission might arise as a result of localized viscous heating due to a gravitational instability in the AB Aurigae disk, or to the presence of a close stellar companion or accreting substellar object. C1 CALTECH, Michelson Sci Ctr, Pasadena, CA 91125 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Lab Astrophys Grenoble, F-38400 St Martin Dheres, France. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA. CEA, Lab Elect Technol Informat, F-30054 Grenoble, France. RP Millan-Gabet, R (reprint author), CALTECH, Michelson Sci Ctr, MS 100-22, Pasadena, CA 91125 USA. EM rafael@ipac.caltech.edu NR 40 TC 24 Z9 24 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 JUL 1 PY 2006 VL 645 IS 1 BP L77 EP L80 DI 10.1086/506153 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 060WS UT WOS:000238833100020 ER PT J AU Smith, CW Hamilton, K Vasquez, BJ Leamon, RJ AF Smith, Charles W. Hamilton, Kathleen Vasquez, Bernard J. Leamon, Robert J. TI Dependence of the dissipation range spectrum of interplanetary magnetic fluctuations on the rate of energy cascade SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; solar wind; turbulence; waves ID SOLAR-WIND; KINETIC DISSIPATION; ALFVEN WAVES; TURBULENCE; FIELD; HELICITY; DYNAMICS AB We investigate the nature of turbulent magnetic dissipation in the solar wind. We employ a database describing the spectra of over 800 intervals of interplanetary magnetic field and solar wind measurements recorded by the ACE spacecraft at 1 AU. We focus on the spectral properties of the dissipation range that forms at spacecraft frequencies >= 0.3 Hz and show that while the inertial range at lower frequencies displays a tightly constrained range of spectral indexes, the dissipation range exhibits a broad range of power-law indexes. We show that the explanation for this variation lies with the dependence of the dissipation range spectrum on the rate of energy cascade through the inertial range such that steeper spectral forms result from greater cascade rates. C1 Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. NASA, Goddard Space Flight Ctr, GSI, Commun L3, Greenbelt, MD 20771 USA. RP Smith, CW (reprint author), Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. EM charles.smith@unh.edu; kmz4@cisunix.unh.edu; bernie.vasquez@unh.edu; leamon@grace.nascom.nasa.gov NR 33 TC 166 Z9 166 U1 0 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 JUL 1 PY 2006 VL 645 IS 1 BP L85 EP L88 DI 10.1086/506151 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 060WS UT WOS:000238833100022 ER PT J AU Eckart, ME Stern, D Helfand, DJ Harrison, FA Mao, PH Yost, SA AF Eckart, Megan E. Stern, Daniel Helfand, David J. Harrison, Fiona A. Mao, Peter H. Yost, Sarah A. TI The Serendipitous Extragalactic X-ray Source Identification (SEXSI) program. III. Optical spectroscopy SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE catalogs; galaxies : active; surveys; X-rays : diffuse background; X-rays : galaxies; X-rays : galaxies : clusters; X-rays : general ID ACTIVE GALACTIC NUCLEI; CHANDRA MULTIWAVELENGTH PROJECT; MEDIUM-SENSITIVITY SURVEY; FORMATION RATE INDICATOR; STAR-FORMING GALAXIES; FIELD-NORTH SURVEY; HELLAS2XMM SURVEY; SKY SURVEY; NUMBER COUNTS; IMAGING SPECTROMETER AB We present the catalog of 477 spectra from the Serendipitous Extragalactic X-ray Source Identification (SEXSI) program, a survey designed to probe the dominant contributors to the 2-10 keV cosmic X-ray background. Our survey covers 1 deg(2) of sky to 2-10 keVfluxes of 1 x 10(-14) ergs cm(-2) s(-1), and 2 deg(2) for fluxes of 3 x 10(-14) ergs cm(-2) s(-1). Our spectra reach to R-band magnitudes of less than or similar to 24 and have produced identifications and redshifts for 438 hard X-ray sources. Typical completeness levels in the 27 Chandra fields studied are 40%-70%. The vast majority of the 2-10 keV selected sample are active galactic nuclei (AGNs) with redshifts between 0.1 and 3; our highest redshift source lies at z = 4.33. We find that few sources at z < 1 have high X-ray luminosities, reflecting a dearth of high-mass, high-accretion-rate sources at low redshift, a result consistent with other recent wide-area surveys. We find that half of our sources show significant obscuration, with N-H > 10(22) cm(-2), independent of unobscured luminosity. We classify 168 sources as emission-line galaxies; all are X-ray-luminous (L-X > 10(41) ergs s(-1)) objects with optical spectra lacking both high-ionization lines and evidence of a nonstellar continuum. The redshift distribution of these emission-line galaxies peaks at a significantly lower redshift than does that of the sources we spectroscopically identify as AGNs. We conclude that few of these sources, even at the low-luminosity end, can be powered by starburst activity. Stacking spectra for a subset of these sources in a similar redshift range, we detect [Ne V] lambda 3426 emission, a clear signature of AGN activity, confirming that the majority of these objects are Seyfert 2 galaxies in which the high-ionization lines are diluted by stellar emission. We find a total of 33 objects lacking broad lines in their optical spectra that have quasar X-ray luminosities (L-X > 10(44) ergs s(-1)), the largest sample of such objects identified to date. In addition, we explore 17 AGNs associated with galaxy clusters and find that the cluster-member AGN sample has a lower fraction of broad-line AGNs than does the background sample. C1 CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Columbia Univ, Dept Astron, New York, NY 10027 USA. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. Univ Michigan, Dept Phys, Randall Lab 2464, Ann Arbor, MI 48109 USA. RP Eckart, ME (reprint author), CALTECH, Space Radiat Lab, 220-47, Pasadena, CA 91125 USA. NR 73 TC 53 Z9 53 U1 0 U2 4 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 JUL PY 2006 VL 165 IS 1 BP 19 EP 56 DI 10.1086/504524 PG 38 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 063TC UT WOS:000239041500002 ER PT J AU Kerbachi, R Boughedaoui, M Bounoua, L Keddam, M AF Kerbachi, Rabah Boughedaoui, Menouer Bounoua, Lahouari Keddam, Malika TI Ambient air pollution by aromatic hydrocarbons in Algiers SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE air pollution; road traffic; BTEX compounds; VOC; Algeria ID VOLATILE ORGANIC-COMPOUNDS; COMPOUNDS VOCS; NONMETHANE HYDROCARBONS; URBAN ATMOSPHERE; LOCATIONS; EMISSIONS; GERMANY; CITIES; SITES AB The analysis of the C-6-C-16 semi-volatile organic compounds reveals the presence of numerous aromatic hydrocarbons in the ambient air of Algiers. Three representative sites were chosen for sample collection at roadside, urban background and semi-rural areas. The following major monocyclic aromatic hydrocarbons were found: benzene, toluene, ethylbenzene, (m,p)- and o-xylene, also referred to as BTEX. Near the road traffic, benzene and toluene mean concentrations were 27 and 39 mu g m(-3), respectively, with benzene concentration values higher than 40 mu g m(-3) often observed. At the urban site, the benzene concentration often exceeds the European regulatory limit of 10 mu g m(-3) while the compositional ratios of toluene to benzene and (m-p) xylene to ethylbenzene are within the typical range of values observed in urban atmospheres worldwide. The seasonal variation indicates a decrease in concentration during summer of the reactive o-xylene compound. It is suggested that Algiers' source of high-level air pollution by aromatic hydrocarbons is related to car traffic emissions. (c) 2006 Elsevier Ltd. All rights reserved. C1 Natl Polytechn Sch Algiers, Algiers 16200, Algeria. Univ Blida, Ind Chem Dept, Blida 09000, Algeria. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Kerbachi, R (reprint author), Natl Polytechn Sch Algiers, BP 183, Algiers 16200, Algeria. EM kerbachi@gecos.net RI Boughedaoui, Menouer/G-5597-2016 OI Boughedaoui, Menouer/0000-0002-3979-8350 NR 36 TC 51 Z9 54 U1 2 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD JUL PY 2006 VL 40 IS 21 BP 3995 EP 4003 DI 10.1016/j.atmosenv.2006.02.033 PG 9 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 060UN UT WOS:000238827200015 ER PT J AU Agogino, AK Tumer, K AF Agogino, AK Tumer, K TI Handling communication restrictions and team formation in congestion games SO AUTONOMOUS AGENTS AND MULTI-AGENT SYSTEMS LA English DT Article DE reinforcement learning; MAS; teams; communication ID COLLECTIVE INTELLIGENCE; COOPERATION; AGENTS AB There are many domains in which a multi-agent system needs to maximize a "system utility" function which rates the performance of the entire system, while subject to communication restrictions among the agents. Such communication restrictions make it difficult for agents that take actions to optimize their own "private" utilities to also help optimize the system utility. In this article we show how previously introduced utilities that promote coordination among agents can be modified to be effective in domains with communication restrictions. The modified utilities provide performance improvements of up to 75 over previously used utilities in congestion games (i.e., games where the system utility depends solely on the number of agents choosing a particular action). In addition, we show that in the presence of severe communication restrictions, team formation for the purpose of information sharing among agents leads to an additional 25 improvement in system utility. Finally, we show that agents' private utilities and team sizes can be manipulated to form the best compromise between how "aligned" an agent's utility is with the system utility and how easily an agent can learn that utility. C1 Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. EM adrian@email.arc.nasa.gov; ktumer@mail.arc.nasa.gov NR 40 TC 8 Z9 9 U1 0 U2 4 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1387-2532 EI 1573-7454 J9 AUTON AGENT MULTI-AG JI Auton. Agents Multi-Agent Syst. PD JUL PY 2006 VL 13 IS 1 BP 97 EP 115 DI 10.1007/s10458-006-6105-y PG 19 WC Automation & Control Systems; Computer Science, Artificial Intelligence SC Automation & Control Systems; Computer Science GA 034FW UT WOS:000236915400004 ER PT J AU Hedges, SB Kumar, S Van Tuinen, M AF Hedges, S. Blair Kumar, Sudhir Van Tuinen, Marcel TI Constraining fossil calibrations for molecular clocks SO BIOESSAYS LA English DT Letter ID EVOLUTION; DIVERSIFICATION; DIVERGENCE; TIMESCALE; RECORD; DATES; TIME; LIFE C1 Penn State Univ, Dept Biol, Mueller Lab 208, University Pk, PA 16802 USA. Penn State Univ, NASA, Astrobiol Inst, University Pk, PA 16802 USA. Arizona State Univ, Ctr Evolut Funct Genom, Biodesign Inst, Tempe, AZ 85287 USA. Arizona State Univ, Sch Life Sci, Tempe, AZ 85287 USA. Stanford Univ, Dept Biol Sci, Stanford, CA 94305 USA. RP Hedges, SB (reprint author), Penn State Univ, Dept Biol, Mueller Lab 208, University Pk, PA 16802 USA. RI Kumar, Sudhir/F-1411-2011 NR 15 TC 7 Z9 8 U1 2 U2 4 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0265-9247 J9 BIOESSAYS JI Bioessays PD JUL PY 2006 VL 28 IS 7 BP 770 EP 771 DI 10.1002/bies.20437 PG 2 WC Biochemistry & Molecular Biology; Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics GA 067SM UT WOS:000239322900011 PM 16850409 ER PT J AU Le Marshall, J Jung, J Derber, J Chahine, M Treadon, R Lord, SJ Goldberg, M Wolf, W Liu, HC Joiner, J Woollen, J Todling, R van Delst, P Tahara, Y AF Le Marshall, J. Jung, J. Derber, J. Chahine, M. Treadon, R. Lord, S. J. Goldberg, M. Wolf, W. Liu, H. C. Joiner, J. Woollen, J. Todling, R. van Delst, P. Tahara, Y. TI Improving global analysis and forecasting with AIRS SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SSI ANALYSIS SYSTEM; RADIANCES C1 NOAA Sci Ctr, Joint Ctr Satellite Data Assimilat, Camp Springs, MD 20746 USA. US Dept Def Joint Ctr Satellite Data Assimilat, Camp Springs, MD USA. NASA Jet Propuls Lab, Pasadena, CA USA. RP Le Marshall, J (reprint author), NOAA Sci Ctr, Joint Ctr Satellite Data Assimilat, 5200 Auth Rd, Camp Springs, MD 20746 USA. EM John.Lemarshall@noaa.gov RI Goldberg, Mitch/F-5589-2010; Wolf, Walter/E-7935-2011; Joiner, Joanna/D-6264-2012 OI Wolf, Walter/0000-0002-2102-8833; NR 7 TC 96 Z9 96 U1 3 U2 5 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 JUL PY 2006 VL 87 IS 7 BP 891 EP 894 DI 10.1175/BAMS-87-891 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 067VH UT WOS:000239330200015 ER PT J AU Chahine, MT Pagano, TS Aumann, HH Atlas, R Barnet, C Blaisdell, J Chen, L Divakarla, M Fetzer, EJ Goldberg, M Gautier, C Granger, S Hannon, S Irion, FW Kakar, R Kalnay, E Lambrigtsen, BH Lee, SY Le Marshall, J McMillan, WW McMillin, L Olsen, ET Revercomb, H Rosenkranz, P Smith, WL Staelin, D Strow, LL Susskind, J Tobin, D Wolf, W Zhou, LH AF Chahine, Moustafa T. Pagano, Thomas S. Aumann, Hartmut H. Atlas, Robert Barnet, Christopher Blaisdell, John Chen, Luke Divakarla, Murty Fetzer, Eric J. Goldberg, Mitch Gautier, Catherine Granger, Stephanie Hannon, Scott Irion, Fredrick W. Kakar, Ramesh Kalnay, Eugenia Lambrigtsen, Bjorn H. Lee, Sung-Yung Le Marshall, John McMillan, W. Wallace McMillin, Larry Olsen, Edward T. Revercomb, Henry Rosenkranz, Philip Smith, William L. Staelin, Did Strow, L. Larrabee Susskind, Joel Tobin, David Wolf, Walter Zhou, Lihang TI Improving weather forecasting and providing new data on greenhouse gases SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID CLOUDY ATMOSPHERES; AIRS DATA; AIRS/AMSU/HSB; PREDICTION; VALIDATION; PRODUCTS AB The Atmospheric Infrared Sounder (AIRS) and its two companion microwave sounders, AMSU and HSB were launched into polar orbit onboard the NASA Aqua Satellite in May 2002. NASA required the sounding system to provide high-quality research data for climate studies and to meet NOAA's requirements for improving operational weather forecasting. The NOAA requirement translated into global retrieval of temperature and humidity profiles with accuracies approaching those of radiosondes. AIRS also provides new measurements of several greenhouse gases, such as CO2, CO, CH4, O-3, SO2, and aerosols. The assimilation of AIRS data into operational weather forecasting has already demonstrated significant improvements in global forecast skill. At NOAA/NCEP, the improvement in the forecast skill achieved at 6 days is equivalent to gaining an extension of forecast capability of six hours. This improvement is quite significant when compared to other forecast improvements over the last decade. In addition to NCEP, ECMWF and the Met Office have also reported positive forecast impacts due AIRS. AIRS is a hyperspectral sounder with 2,378 infrared channels between 3.7 and 15.4 mu m. NOAA/NESDIS routinely distributes AIRS data within 3 hours to NWP centers around the world. The AIRS design represents a breakthrough in infrared space instrumentation with measurement stability and accuracies far surpassing any current research or operational sounder. The results we describe in this paper are "work in progress," and although significant accomplishments have already been made much more work remains in order to realize the full potential of this suite of instruments. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91109 USA. NASA Goddard Space Flight Ctr, Greenbelt, MD USA. NOAA NESDIS, Camp Springs, MD USA. SAIC, Beltsville, MD USA. STG Inc, Reston, VA USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. NASA Headquarters, Washington, DC USA. Univ Maryland, College Pk, MD 20742 USA. Joint Ctr Satellite Data Assimilat, Camp Springs, MD USA. Univ Maryland, Baltimore, MD 21201 USA. Univ Wisconsin, Madison, WI 53706 USA. MIT, Cambridge, MA 02139 USA. Hampton Univ, Hampton, VA USA. QSS Grp, Lanham, MD USA. RP Chahine, MT (reprint author), CALTECH, Jet Propuls Lab, Pasadena, CA 91109 USA. EM chahine@jpl.nasa.gov RI Kalnay, Eugenia/F-4393-2010; Atlas, Robert/A-5963-2011; Goldberg, Mitch/F-5589-2010; Barnet, Christopher/F-5573-2010; Divakarla, Murty/E-7936-2011; Wolf, Walter/E-7935-2011; Zhou, Lihang/E-7938-2011 OI Atlas, Robert/0000-0002-0706-3560; Divakarla, Murty/0000-0002-0399-3381; Wolf, Walter/0000-0002-2102-8833; Zhou, Lihang/0000-0001-6232-2871 NR 26 TC 304 Z9 307 U1 4 U2 33 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 JUL PY 2006 VL 87 IS 7 BP 911 EP + DI 10.1175/BAMS-87-7-911 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 067VH UT WOS:000239330200017 ER PT J AU Lawford, R Bosilovich, M Eden, S Benedict, S Brown, C Gruber, A Houser, P Hsu, K Huang, J Lau, W Meyers, T Mitchell, K Peters-Lidard, C Roads, J Rodell, M Sorooshian, S Tarpley, D Williams, S AF Lawford, Richard Bosilovich, Mike Eden, Susanna Benedict, Sam Brown, Constance Gruber, Arnold Houser, Paul Hsu, Kuolin Huang, Jin Lau, William Meyers, Tilden Mitchell, Kenneth Peters-Lidard, Christa Roads, John Rodell, Matt Sorooshian, Soroosh Tarpley, Dan Williams, Steve TI US contributions to the CEOP SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID LAND-SURFACE EVAPORATION; TROPICAL RAINFALL; SYSTEM; TEMPERATURE; BOUNDARY; MISSION; COVER; SCALE; INDEX AB THE CEOP The Coordinated Enhanced Observing Period (CEOP) is an international project that was first proposed by the Global Energy and Water Cycle Experiment (GEWEX) in 1997 and was formally launched in 2001. Since that time it has been adopted by the World Climate Research Programme (WCRP), which views it as an essential part of its strategy for developing global datasets to evaluate global climate models, and by the Integrated Global Observing Strategy Partnership (IGOS-P), which views it as the first element of its global water cycle theme. The United States has been an active partner in all phases of CEOP. In particular, the United States has taken the lead in contributing data from a number of reference sites, providing data processing, and archiving capabilities and related research activities through the GEWEX Americas Prediction Project (GAPP). Other U.S. programs and agencies are providing components including model and data assimilation output, satellite data, and other services. The U.S. science community has also been using the CEOP database in model evaluation and phenomenological studies. This article summarizes the U.S. contributions during the first phase of CEOP and outlines opportunities for readers to become involved in the data analysis phase of the project. C1 Int GEWEX Project Off, Silver Spring, MD USA. NASA, Greenbelt, MD USA. Univ Arizona, Tucson, AZ USA. CEOP Int Project Off, San Diego, CA USA. Indiana Univ, Bloomington, IN USA. Univ Maryland, College Pk, MD 20742 USA. George Mason Univ, Fairfax, VA 22030 USA. NOAA, Silver Spring, MD USA. NOAA, Oak Ridge, TN USA. NOAA, Camp Springs, MD USA. Scripps Inst Oceanog, La Jolla, CA USA. NCAR, Boulder, CO USA. RP Lawford, R (reprint author), 1010 Wayne Ave,Suite 450, Silver Spring, MD 20910 USA. EM lawford@umbc.edu RI Peters-Lidard, Christa/E-1429-2012; Rodell, Matthew/E-4946-2012; sorooshian, soroosh/B-3753-2008; Bosilovich, Michael/F-8175-2012; Houser, Paul/J-9515-2013; Lau, William /E-1510-2012; Meyers, Tilden/C-6633-2016 OI Peters-Lidard, Christa/0000-0003-1255-2876; Rodell, Matthew/0000-0003-0106-7437; sorooshian, soroosh/0000-0001-7774-5113; Houser, Paul/0000-0002-2991-0441; Lau, William /0000-0002-3587-3691; NR 36 TC 11 Z9 11 U1 2 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 EI 1520-0477 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUL PY 2006 VL 87 IS 7 BP 927 EP 939 DI 10.1175/BAMS-87-7-927 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 067VH UT WOS:000239330200018 ER PT J AU Ferrante, J Zypman, FR AF Ferrante, John Zypman, Fredy R. TI Generalization of equivalent crystal theory to include angular dependence SO COMPUTATIONAL MATERIALS SCIENCE LA English DT Article DE equivalent crystal theory; surface formation energy; vacancy energy curve ID INTERFACES; SURFACES; METALS AB The original equivalent crystal theory is a semi-empirical method for calculating the configurational energy of atomic systems. Each atomic site in the real crystal with defects is assigned an equivalent lattice constant, in general different from the around state value. This parameter corresponds to a local compression or expansion of the perfect lattice. The basic method considers these volumetric transformations and, in addition, introduces the possibility that the reference lattice is anisotropically distorted. These distortions however, were introduced ad-hoc. In this work, we generalize the original Equivalent Crystal Theory by introducing site-dependent directional distortions of the lattice which account for the dependence of the energy oil anisotropic local density variations. This is done in the spirit of the original framework of ECT. but includes a gradient in the density. This approach is introduced to ECT and may apply to other semi-empirical methods by making use of readily available first-principles results to fix parameters. We develop here the basic framework, and apply it to the calculation of Fe(I 10) and Fe(I 1 1) surface energy formation, and to the vacancy energy curve. The results, compared with first-principles calculations. show an improvement over previous semi-empirical approaches. (c) 2005 Published by Elsevier B.V. C1 Yeshiva Univ, Dept Phys, New York, NY 10033 USA. NASA Glenn, Cleveland, OH 44135 USA. RP Zypman, FR (reprint author), Yeshiva Univ, Dept Phys, 2495 Amsterdam Ave, New York, NY 10033 USA. EM zypman@yu.edu NR 11 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0256 EI 1879-0801 J9 COMP MATER SCI JI Comput. Mater. Sci. PD JUL PY 2006 VL 36 IS 4 BP 425 EP 431 DI 10.1016/j.commatsci.2005.06.013 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA 055TT UT WOS:000238474000007 ER PT J AU LeBleu, VS Thornton, M Gonda, SR Helmstetter, CE AF LeBleu, Valerie S. Thornton, Maureen Gonda, Steven R. Helmstetter, Charles E. TI Technology for cell cycle research with unstressed steady-state cultures SO CYTOTECHNOLOGY LA English DT Article DE steady-state culture; cell cycle; continuous culture; rotating culture ID BABY MACHINE; MAMMALIAN-CELLS; SYNCHRONOUS CULTURES; HEMATOPOIETIC-CELLS; DNA-REPLICATION; HELA-CELLS; SYNCHRONIZATION; DIVISION; GROWTH AB A culture system for performing cell cycle analyses on cells in undisturbed steady-state populations was designed and tested. In this system, newborn cells are shed continuously from an immobilized, perfused culture rotating about the horizontal axis. As a result of this arrangement, the number of newborn cells released into the effluent medium each generation is identical to the number of cells residing in the immobilized population, indicating that one of the two new daughter cells is shed at each cell division. Thus, the immobilized cells constitute a continuous, steady-state culture because the concentrations, locations and microenvironments of the cells in the culture vessel do not vary with time. In tests with mouse L1210 lymphocytic leukemia cells, about 10(8) newborn cells were produced per day. This new culture system enables a multiplicity of cell cycle analyses on large numbers of cells assured to be from populations in steady-state growth. C1 Harvard Univ, Sch Med, Div Matrix Biol, Kalluri Lab,Biol & Biomed Sci Program,BIDMC, Boston, MA 02446 USA. Florida Inst Technol, Dept Biol Sci, Melbourne, FL 32901 USA. Midwest Res Inst, Florida Div, Palm Bay, FL 32909 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP LeBleu, VS (reprint author), Harvard Univ, Sch Med, Div Matrix Biol, Kalluri Lab,Biol & Biomed Sci Program,BIDMC, DANA 515,330 Brookline Ave, Boston, MA 02446 USA. EM valerie_lebleu@hms.harvard.edu RI LeBleu, Valerie /E-2991-2015 FU NIA NIH HHS [R01 AG021508] NR 24 TC 5 Z9 5 U1 0 U2 3 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0920-9069 J9 CYTOTECHNOLOGY JI Cytotechnology PD JUL PY 2006 VL 51 IS 3 BP 149 EP 157 DI 10.1007/s10616-006-9024-5 PG 9 WC Biotechnology & Applied Microbiology; Cell Biology SC Biotechnology & Applied Microbiology; Cell Biology GA 111AH UT WOS:000242422300004 PM 19002885 ER PT J AU Kilic, B Madenci, E Ambur, DR AF Kilic, B Madenci, E Ambur, DR TI Influence of adhesive spew in bonded single-lap joints SO ENGINEERING FRACTURE MECHANICS LA English DT Article DE single lap joint; bonded; adhesive; energy release rate ID ELEMENT ITERATIVE METHOD; SINGULAR STRESS-FIELDS; DISSIMILAR MATERIALS; COMPUTATIONAL ANALYSIS; NONLINEAR-ANALYSIS; EIGENVALUE PROBLEM; FINITE-ELEMENTS; INTERFACE; MULTIPLE; BEHAVIOR AB Adhesively bonded lap joints involve dissimilar material junctions and sharp changes in geometry, possibly leading to premature failure. Although the finite element method is well suited to model the bonded lap joints, traditional finite elements are incapable of correctly resolving the stress state at junctions of dissimilar materials because of the unbounded nature of the stresses. In order to facilitate the use of bonded lap joints in future structures, this study presents a finite element technique utilizing a global (special) element coupled with traditional elements. The global element includes the singular behavior at the junction of dissimilar materials with or without traction-free surfaces. (c) 2006 Elsevier Ltd. All rights reserved. C1 Univ Arizona, Dept Aerosp & Mech Engn, Tucson, AZ 85721 USA. NASA, Glenn Res Ctr, Struct Div, Cleveland, OH 44135 USA. RP Madenci, E (reprint author), Univ Arizona, Dept Aerosp & Mech Engn, POB 210119, Tucson, AZ 85721 USA. EM bkilic@email.arizona.edu; madenci@email.arizona.edu; Damodar.R.Ambur@nasa.gov NR 41 TC 14 Z9 16 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0013-7944 J9 ENG FRACT MECH JI Eng. Fract. Mech. PD JUL PY 2006 VL 73 IS 11 BP 1472 EP 1490 DI 10.1016/j.engfracmech.2005.12.015 PG 19 WC Mechanics SC Mechanics GA 054BF UT WOS:000238349800003 ER PT J AU Carls, MG AF Carls, Mark G. TI Nonparametric identification of petrogenic and pyrogenic hydrocarbons in aquatic ecosystems SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID POLYCYCLIC AROMATIC-HYDROCARBONS; PRINCE-WILLIAM-SOUND; BASE-LINE CONDITIONS; WEATHERED CRUDE-OIL; EXXON-VALDEZ OIL; SEDIMENTS; ALASKA; PAHS; TOXICITY; DOCUMENT AB Novel nonparametric models developed herein discriminated between oiled and nonoiled or pyrogenic and oiled sources better than traditionally used diagnostic ratios and can outperform previously published oil identification models. These methods were compared using experimental and environmental hydrocarbon data (sediment, mussels, water, and fish) associated with the Exxon Valdez oil spill. Several nonparametric models were investigated, one designed to detect petroleum in general, one specific to Alaska North Slope crude oil (ANS), and one designed to detect pyrogenic PAH. These ideas are intended as guidance; nonparametric models can easily be adapted to fit the specific needs of a variety of petrogenic and pyrogenic sources. Oil identification was clearly difficult where composition was modified by physical or biological processes; model results differed most in these cases, suggesting that a multiple model approach to source discrimination may be useful where data interpretation is contentious. However, a combined nonparametric model best described a broad range of hydrocarbon sources, thus providing a useful new analytical assessment tool. C1 Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, Natl Ocean & Atmospher Adm, Auke Bay Lab, Juneau, AK 99801 USA. RP Carls, MG (reprint author), Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, Natl Ocean & Atmospher Adm, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. EM mark.carls@noaa.gov NR 27 TC 9 Z9 9 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD JUL 1 PY 2006 VL 40 IS 13 BP 4233 EP 4239 DI 10.1021/es052498g PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 058DQ UT WOS:000238645400035 PM 16856740 ER PT J AU Olsen, N Luhr, H Sabaka, TJ Mandea, M Rother, M Tofner-Clausen, L Choi, S AF Olsen, N Luhr, H Sabaka, TJ Mandea, M Rother, M Tofner-Clausen, L Choi, S TI CHAOS-a model of the Earth's magnetic field derived from CHAMP, Orsted, and SAC-C magnetic satellite data SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE Earth's magnetic field; geomagnetic secular variation; geomagnetism; lithosphere; satellite; spherical harmonics ID GEOMAGNETIC-FIELD; BOUNDARY; MAGSAT AB We have derived a model of the near-Earth magnetic field (up to spherical harmonic degree n= 50 for the static field, and up to n = 18 for the first time derivative) using more than 6.5 yr of high-precision geomagnetic measurements from the three satellites Orsted, CHAMP and SAC-C taken between 1999 March and 2005 December. Our modelling approach goes in several aspects beyond that used for recent models: (i) we use different data selection criteria and allow for higher geomagnetic activity (index Kp <= 2o), thus we include more data than previous models; (ii) we describe the temporal variation of the core field by splines (for n <= 14); (iii) we take magnetometer vector data in the instrument frame and co-estimate the Euler angles that describe the transformation from the magnetometer frame to the star imager frame, avoiding the inconsistency of using vector data that have been aligned using a different (pre-existing) field model; (iv) we account for the bending of the CHAMP optical bench connecting magnetometer and star imager by estimating Euler angles in 10 day segments and (v) we co-estimate degree-1 external fields separately for every 12 hr interval. The model provides a reliable representation of the static (core and crustal) field up to spherical harmonic degree n = 40, and of the first time derivative up to n = 15. C1 Danish Natl Space Ctr, DK-2100 Copenhagen, Denmark. Geoforschungszentrum Potsdam, D-14473 Potsdam, Germany. NASA, Goddard Space Flight Ctr, Geodynam Branch, Greenbelt, MD 20771 USA. RP Olsen, N (reprint author), Danish Natl Space Ctr, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark. EM nio@spacecenter.dk RI Olsen, Nils/H-1822-2011; Sabaka, Terence/D-5618-2012; MANDEA, Mioara/E-4892-2012 OI Olsen, Nils/0000-0003-1132-6113; NR 31 TC 124 Z9 132 U1 2 U2 9 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0956-540X J9 GEOPHYS J INT JI Geophys. J. Int. PD JUL PY 2006 VL 166 IS 1 BP 67 EP 75 DI 10.1111/j.1365-246X.2006.02959.x PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 059QW UT WOS:000238748300006 ER PT J AU Arimoto, R Kim, YJ Kim, YP Quinn, PK Bates, TS Anderson, TL Gong, S Uno, I Chin, M Huebert, BJ Clarke, AD Shinozuka, Y Weber, RJ Anderson, JR Guazzotti, SA Sullivan, RC Sodeman, DA Prather, KA Sokolik, IN AF Arimoto, R. Kim, Y. J. Kim, Y. P. Quinn, P. K. Bates, T. S. Anderson, T. L. Gong, S. Uno, I. Chin, M. Huebert, B. J. Clarke, A. D. Shinozuka, Y. Weber, R. J. Anderson, J. R. Guazzotti, S. A. Sullivan, R. C. Sodeman, D. A. Prather, K. A. Sokolik, I. N. TI Characterization of Asian Dust during ACE-Asia SO GLOBAL AND PLANETARY CHANGE LA English DT Review DE Asian dust; aerosols; chemistry; radiative effects; climate ID AEROSOL OPTICAL-PROPERTIES; ARTIFICIAL NEURAL-NETWORK; FLIGHT MASS-SPECTROMETRY; TRANS-PACIFIC TRANSPORT; LONG-RANGE TRANSPORT; MINERAL DUST; CHEMICAL-COMPOSITION; HETEROGENEOUS CHEMISTRY; RADIATIVE PROPERTIES; SINGLE PARTICLES AB ACE-Asia was a multi-national collaboration organized to investigate and understand the chemistry, radiative properties, and climatic effects of mineral dust and other aerosol particles in the East Asia/Northwest Pacific region. Studies conducted at the Gosan and Zhenbeitai surface supersites show striking variations in aerosol concentrations and properties that were affected by the occurrence and origins of the Asian dust storms, air mass pathways, and mixing during the transport. Investigations conducted on the RN Ronald H. Brown (RHB) showed that dust had a pervasive influence on the chemical composition, size distribution, and optical properties of the aerosol. Analyses using an aerosol time-of-flight mass spectrometer on the RHB showed that most of the coarse-particle nitrate and sulfate in post-frontal air was associated with dust, and more remarkably, that competitive or exclusionary processes evidently are involved in the uptake or production of these substances. Studies conducted onboard the NCAR C-130 aircraft showed that coarse-mode dust was less absorbing and less hygroscopic than pollution aerosol and that there was little correlation in light scattering and absorption by the sub- vs. super-micrometer aerosol. Below similar to 2 km, dust was commonly mixed with pollutants, and this had a stronger influence on the optical properties of the submicrometer particles than the coarse-mode dust; at higher altitudes, the dust was less affected by pollution. Single particle analyses of C-130 samples showed that the mixing of black carbon (BC) with dust was common, but only certain types of BC particles were aggregated. Models were used in the planning, execution and interpretative phases of ACE-Asia; and summaries of modeling results are presented to illustrate the progress being made in identifying new dust sources; in depicting the time-varying, three-dimensional structure of dust plumes; and in quantifying the production, transport, and deposition of Asian dust. (C) 2006 Elsevier B.V. All rights reserved. C1 New Mexico State Univ, Carlsbad Environm Monitoring & Res Ctr, Carlsbad, NM 88220 USA. Gwangju Inst Sci & Technol, Dept Environm Sci & Engn, Adv Environm Monitoring Res Ctr, Kwangju 500712, South Korea. Ewha Womans Univ, Dept Environm Sci & Engn, Seoul 120750, South Korea. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Atmospher Environm Serv, Air Qual Res Branch, Toronto, ON M3H 5T4, Canada. Kyushu Univ, Appl Mech Res Inst, Fukuoka 8168580, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Hawaii Manoa, Sch Ocean & Earth Sci, Honolulu, HI 96822 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Arizona State Univ, Environm Fluid Dynam, Tempe, AZ 85287 USA. Univ Calif San Diego, Dept Chem & Biochem, La Jolla, CA 92093 USA. RP Arimoto, R (reprint author), New Mexico State Univ, Carlsbad Environm Monitoring & Res Ctr, Carlsbad, NM 88220 USA. EM arimoto@cemrc.org RI Uno, Itsushi/B-5952-2011; Sullivan, Ryan/B-4674-2008; Chin, Mian/J-8354-2012; Prather, Kimberly/A-3892-2008; Kim, Yong/H-3109-2014; Kyushu, RIAM/F-4018-2015; U-ID, Kyushu/C-5291-2016; Bates, Timothy/L-6080-2016; Quinn, Patricia/R-1493-2016 OI Sullivan, Ryan/0000-0003-0701-7158; Prather, Kimberly/0000-0003-3048-9890; Kim, Yong/0000-0002-3753-7739; Quinn, Patricia/0000-0003-0337-4895 NR 111 TC 119 Z9 127 U1 2 U2 37 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 JUL PY 2006 VL 52 IS 1-4 BP 23 EP 56 DI 10.1016/j.gloplacha.2006.02.013 PG 34 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 066SD UT WOS:000239249500002 ER PT J AU Salinari, F Giosue, S Tubiello, FN Rettori, A Rossi, V Spanna, F Rosenzweig, C Gullino, ML AF Salinari, F Giosue, S Tubiello, FN Rettori, A Rossi, V Spanna, F Rosenzweig, C Gullino, ML TI Downy mildew (Plasmopara viticola) epidemics on grapevine under climate change SO GLOBAL CHANGE BIOLOGY LA English DT Article DE climate change; disease pressure; epidemiology; GCM scenarios; impacts and adaptation; modelling; oomycota; plant disease; primary infections ID ELEVATED CO2; POTENTIAL IMPACT; PLANT-DISEASES; CARBON-DIOXIDE; MODEL; SIMULATION; AGRICULTURE; O-3; US AB As climate is a key agro-ecosystem driving force, climate change could have a severe impact on agriculture. Many assessments have been carried out to date on the possible effects of climate change (temperature, precipitation and carbon dioxide concentration changes) on plant physiology. At present however, likely effects on plant pathogens have not been investigated deeply. The aim of this work was to simulate future scenarios of downy mildew (Plasmopara viticola) epidemics on grape under climate change, by combining a disease model to output from two general circulation models (GCMs). Model runs corresponding to the SRES-A2 emissions scenario, characterized by high projections of both population and greenhouse gas emissions from present to 2100, were chosen in order to investigate impacts of worst-case scenarios, among those currently available from IPCC. Three future decades were simulated (2030, 2050, 2080), using as baseline historical series of meteorological data collected from 1955 to 2001 in Acqui Terme, an important grape-growing area in the north-west of Italy. Both GCMs predicted increase of temperature and decrease of precipitation in this region. The simulations obtained by combining the disease model to the two GCM outputs predicted an increase of the disease pressure in each decade: more severe epidemics were a direct consequence of more favourable temperature conditions during the months of May and June. These negative effects of increasing temperatures more than counterbalanced the effects of precipitation reductions, which alone would have diminished disease pressure. Results suggested that, as adaptation response to future climate change, more attention would have to be paid in the management of early downy mildew infections; two more fungicide sprays were necessary under the most negative climate scenario, compared with present management regimes. At the same time, increased knowledge on the effects of climate change on host-pathogen interactions will be necessary to improve current predictions. C1 Univ Turin, Ctr Competence Agroenvironm Sector, AGROINNOVA, I-10095 Grugliasco, TO, Italy. Catholic Univ, Dept Entomol & Plant Pathol, I-29100 Piacenza, Italy. Columbia Univ, New York, NY 10025 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Agrometeo Sector, Reg Phytosanit Serv, I-10044 Turin, Italy. RP Salinari, F (reprint author), Univ Turin, Ctr Competence Agroenvironm Sector, AGROINNOVA, Via L Vinci 44, I-10095 Grugliasco, TO, Italy. EM francesca.salinari@unito.it RI Rossi, Vittorio/I-7869-2012 OI Rossi, Vittorio/0000-0003-4090-6117 NR 39 TC 53 Z9 57 U1 4 U2 38 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 JUL PY 2006 VL 12 IS 7 BP 1299 EP 1307 DI 10.1111/j.1365-2486.2006.01175.x PG 9 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 054CE UT WOS:000238352800012 ER PT J AU Straume, T Anspaugh, LR Marchetti, AA Voigt, G Minenko, V Gu, F Men, P Trofimik, S Tretyakevich, S Drozdovitch, V Shagalova, E Zhukova, O Germenchuk, M Berlovich, S AF Straume, T. Anspaugh, L. R. Marchetti, A. A. Voigt, G. Minenko, V. Gu, F. Men, P. Trofimik, S. Tretyakevich, S. Drozdovitch, V. Shagalova, E. Zhukova, O. Germenchuk, M. Berlovich, S. TI Measurement of I-129 and Cs-137 in soils from Belarus and reconstruction of I-131 deposition from the Chernobyl accident SO HEALTH PHYSICS LA English DT Article DE accidents; power reactor; I-129; Chernobyl; soil ID ACCELERATOR MASS-SPECTROMETRY; REPROCESSING PLANT; REACTOR ACCIDENT; DEER THYROIDS; SURFACE SOILS; NUCLEAR; IODINE; RADIOISOTOPES; ENVIRONMENT; SAMPLES AB I-129 and Cs-137 have been measured in a large number of soil samples collected throughout the country of Belarus to support efforts for thyroid-dose reconstruction following the Chernobyl accident. Samples of soil consisting of multiple 30-cm-deep cores per site were sampled following a selection process to ensure sites were undisturbed and representative. Samples were measured by accelerator mass spectrometry (AMS) for I-129, gamma spectrometry for Cs-137, and gas chromatography (GC) for total iodine. Results show that both I-129 and Cs-137 are retained firmly in the top similar to 15 to 20 em of the soil. Our results also suggest that the correlation between I-129 and Cs-137 deposition across the country of Belarus is poor; hence, I-129 is a better surrogate for I-131 than is (CS)-C-137. It was also noted that total iodine concentrations in topsoil from Belarus are low compared with other regions of the world where radiogenic thyroid cancer has been studied. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Utah, Salt Lake City, UT 84108 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. IAEA, Agcy Labs Seibersdorf, A-1400 Vienna, Austria. Res & Clin Inst Radiat Med & Endocrinol, Minsk, Byelarus. Int Agcy Res Canc, F-69008 Lyon, France. Republ Ctr Radiat Control & Monitoring Nat Enviro, Minsk, Byelarus. RP Straume, T (reprint author), NASA, Ames Res Ctr, MS 239-11, Moffett Field, CA 94035 USA. EM tstraume@mail.arc.nasa.gov NR 36 TC 20 Z9 20 U1 5 U2 9 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD JUL PY 2006 VL 91 IS 1 BP 7 EP 19 DI 10.1097/01.HP.0000184672.67781.a3 PG 13 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 054AC UT WOS:000238346700002 PM 16775475 ER PT J AU Rao, ST Finlayson, S He, CJ Lacey, R Wheeler, R Davies, FT AF Rao, Sleetal Finlayson, Scott He, Chuanjiu Lacey, Ronald Wheeler, Raymond Davies, Fred T. TI Effect of hypobaria on the expression of ethylene biosynthesis genes in Arabidopsis thaliana SO HORTSCIENCE LA English DT Meeting Abstract C1 Texas A&M Univ, College Stn, TX 77843 USA. NASA, Kennedy Space Ctr, Biol Sci Off, Kennedy Space Ctr, FL USA. NR 0 TC 2 Z9 2 U1 0 U2 1 PU AMER SOC HORTICULTURAL SCIENCE PI ALEXANDRIA PA 113 S WEST ST, STE 200, ALEXANDRIA, VA 22314-2851 USA SN 0018-5345 J9 HORTSCIENCE JI Hortscience PD JUL PY 2006 VL 41 IS 4 MA 148 BP 1059 EP 1059 PG 1 WC Horticulture SC Agriculture GA 063UP UT WOS:000239045700524 ER PT J AU Edney, SL Richards, JT Sisko, MD Yorio, NC Stuttel, GW Wheeler, RM AF Edney, Sharon L. Richards, Jeffrey T. Sisko, Matthew D. Yorio, Neil C. Stuttel, Gary W. Wheeler, Raymond M. TI Evaluation of salad crop growth under environmental conditions for space exploration using mixed crop versus monoculture hydroponic systems SO HORTSCIENCE LA English DT Meeting Abstract C1 Dynam Corp, Kennedy Space Ctr, Food & Crop Syst, Kennedy Space Ctr, FL 32899 USA. NASA, Biol Sci Off, Kennedy Space Ctr, FL 32899 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER SOC HORTICULTURAL SCIENCE PI ALEXANDRIA PA 113 S WEST ST, STE 200, ALEXANDRIA, VA 22314-2851 USA SN 0018-5345 J9 HORTSCIENCE JI Hortscience PD JUL PY 2006 VL 41 IS 4 MA 33 BP 1076 EP 1077 PG 2 WC Horticulture SC Agriculture GA 063UP UT WOS:000239045700603 ER PT J AU Bakalian, F Hartle, RE AF Bakalian, Faez Hartle, Richard E. TI Monte Carlo computations of the escape of atomic nitrogen from Mars SO ICARUS LA English DT Article DE Mars, atmosphere; aeronomy; atmospheres, evolution; atmospheres, structure; ionospheres ID HOT OXYGEN-ATOMS; TERRESTRIAL PLANET THERMOSPHERES; NON-MAXWELLIAN ATMOSPHERE; EARTHS UPPER ATMOSPHERE; SOLAR-CYCLE VARIATION; CROSS-SECTIONS; COLLISIONAL DISSOCIATION; HYDROGEN DIFFUSION; CRITICAL LEVEL; UPPER LIMITS AB Monte Carlo Simulations were carried out to compute the escape flux of atomic nitrogen for the low and high solar activity martian thermospheres. The total escape of atomic nitrogen at low and high solar activities was found to be 3.03 x 10(5) and 1.32 x 10(6) cm(-2) s(-1) respectively. The escape flux of atomic nitrogen at low and high solar activities from photodissociation of N-2 was found to be 2.75 x 10(5) and 9.90 x 10(5) cm(-2) s(-1). respectively. The remainder of the contribution is from dissociative recombination, which is only important at high solar activity were it comprises about 25% of the total escape. The relative contributions to the total N escape flux from thermal motion of the background atmosphere. winds and co-rotation, and photoionization and subsequent solar wind pickup are also considered here. We find that the total predicted escape fluxes are observed to increase by 20 and 25% at low and high solar activities owing to thermal motion of the background atmosphere. At low and high solar activities, we find that the co-rotation and wind velocities combined translate to a maximum transferable energy of similar to 0.0103 and 0.0181 eV. respectively, and that the total escape flux contribution from winds and co-rotation is negligible. Photoionization was found to be a minor process only impacting those source atoms produced with energies close to the escape energy, between 1.5 and 2 eV. The contributions to the total escape fluxes at low and high solar activities from photoionization and subsequent solar wind pickup are found to be about 8 and 13% respectively. (c) 2006 Elsevier Inc. All rights reserved. C1 SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Stony Brook, NY 11777 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Bakalian, F (reprint author), SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Stony Brook, NY 11777 USA. EM faez@atmsci.msrc.sunysb.edu NR 51 TC 7 Z9 7 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD JUL PY 2006 VL 183 IS 1 BP 55 EP 68 DI 10.1016/j.icarus.2006.02.004 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 054EU UT WOS:000238360400005 ER PT J AU Fischer, G Desch, MD Zarka, P Kaiser, ML Gurnett, D Kurth, WS Macher, W Rucker, HO Lecacheux, A Farrell, WM Cecconi, B AF Fischer, G. Desch, M. D. Zarka, P. Kaiser, M. L. Gurnett, D. A. Kurth, W. S. Macher, W. Rucker, H. O. Lecacheux, A. Farrell, W. M. Cecconi, B. TI Saturn lightning recorded by Cassini/RPWS in 2004 SO ICARUS LA English DT Article DE saturn; saturn, atmosphere ID ELECTROSTATIC DISCHARGES; RADIO; VOYAGER-1; JUPITER; PLANETS; MODEL AB During 2004 the Cassini/RPWS (Radio and Plasma Wave Science) instrument recorded about 5400 SEDs (Saturn Electrostatic Discharges), which were organized in 4 storm systems and 95 episodes. A computer algorithm with different intensity thresholds was applied to extract the SEDs from the RPWS data, and a statistical analysis on the main characteristics of these SEDs is performed. Compared to the SEDs recorded by the Voyagers in the early 1980s, some characteristics like SED rate, intensity, signal duration, or power spectrum are similar, but there are also remarkable differences with regard to time occurrence and frequency range: The first appearance of SEDs (storm 0) was recorded by RPWS from a distance of more than 300 Saturn radii at the end of May 2004, followed by storm A in mid-July, storm B at the beginning of August, and the most prominent storm C throughout most of September. There were also significant intervals of time with no detectable SED activity, e.g., SEDs were practically absent from October 2004 until June 2005. No clear indication for SEDs below a frequency of 1.3 MHz could be found. We suggest that the SED storms A, B, C, and possibly also storm 0 originate from the same storm system residing at a latitude of 35 degrees South, which lasted for several months, waxed and waned in strength, and rotated with the Voyage radio period of Saturn. The SED source might be located in the updrafting water clouds beneath the visible cloud features detected in the Cassini images. (c) 2006 Elsevier Inc. All rights reserved. C1 Austrian Acad Sci, Space Res Inst, A-8042 Graz, Austria. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Observ Paris, F-92195 Meudon, France. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. RP Fischer, G (reprint author), Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria. EM gf@space.physics.uiowa.edu RI Farrell, William/I-4865-2013; OI Kurth, William/0000-0002-5471-6202 NR 31 TC 34 Z9 34 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 JUL PY 2006 VL 183 IS 1 BP 135 EP 152 DI 10.1016/j.icarus.2006.02.010 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 054EU UT WOS:000238360400012 ER PT J AU Mastrapa, RME Brown, RH AF Mastrapa, Rachel M. E. Brown, Robert H. TI Ion irradiation of crystalline H(2)O-ice: Effect on the 1.65-mu m band SO ICARUS LA English DT Article DE ices; infrared observations; Kuiper belt objects; radiation chemistry; spectroscopy ID AMORPHOUS SOLID WATER; KUIPER-BELT; D2O ICE; ULTRAVIOLET-IRRADIATION; INDUCED AMORPHIZATION; PROTON IRRADIATION; ASTROPHYSICAL ICES; INFRARED-SPECTRA; OORT CLOUD; H2O ICE AB We have found that 0.8 MeV proton irradiation of crystalline H(2)O-ice results in temperature dependent amorphization. The H(2)O-ice's phase was determined using the near infrared spectrum from 1.0 mu m (10,000 cm(-1)) to 2.5 mu m (4000 cm(-1)). In crystalline H(2)O-ice, the 1.65-mu m (6061 cm(-1)) band is strong while it is nearly absent in the amorphous spectrum [Schmitt, B., Quirico, E., Trotta, F., Grundy, W.M., 1998. In: Schmitt. B.. de Bergh. C.. Festou, M. (Eds.). Solar System Ices. Kluwer Academic, Norwell, MA, 1998, pp. 199-240]. In this experiment, at low temperatures (9, 25. and 40 K), irradiation of crystalline H(2)O-ice produced the amorphous H(2)O-ice's spectrum. However, at 50 K, some crystalline absorptions persisted after irradiation and at 70 and 100 K the crystalline spectrum showed only slight changes after irradiation. Our results agree with previous H(2)O-ice irradiation studies examining the crystalline peaks near 44 and 62 mu m by Moore and Hudson [Moore, M.H.. Hudson. R.L.. 1992. Astrophys. J. 401, 353-360] and near 3.07 mu m by Strazzulla et al. [Strazzulla, G., Baratta, G.A., Leto, G., Foti, G., 1992. Europhys. Lett. 18. 517-522] and by Leto and Baratta [Leto, G., Baratta, G.A., 2003. Astron. Astrophys. 397, 7-13]. We present a method of measuring band areas to quantity the phase and radiation dose of icy Solar System surfaces. (c) 2006 Elsevier Inc. All rights reserved. C1 NASA, Ames Res Ctr, Astrophys Branch, Moffett Field, CA 94035 USA. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. RP Mastrapa, RME (reprint author), NASA, Ames Res Ctr, Astrophys Branch, Mail Stop 245-6, Moffett Field, CA 94035 USA. EM rmastrapa@arc.nasa.gov NR 51 TC 47 Z9 47 U1 0 U2 5 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 JUL PY 2006 VL 183 IS 1 BP 207 EP 214 DI 10.1016/j.icarus.2006.02.006 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 054EU UT WOS:000238360400019 ER PT J AU Forsberg, A Prabhat Haley, G Bragdon, A Levy, J Fassett, CI Shean, D Head, JW Milkovich, S Duchaineau, MA AF Forsberg, Andrew Prabhat Haley, Graff Bragdon, Andrew Levy, Joseph Fassett, Caleb I. Shean, David Head, James W., III Milkovich, Sarah Duchaineau, Mark A. TI Adviser: Immersive field work for planetary geoscientists SO IEEE COMPUTER GRAPHICS AND APPLICATIONS LA English DT Article ID VISUALIZATION; EXPLORATION; MARS AB The Adviser prototype system makes it possible for planetary geologists to conduct virtual field research on remote environments such as Antarctica and Mars. Among Adviser's interactive tools are mission-planning and measurement tools that let researchers generate new data and gain interpretive insights. Five case studies illustrate the system's applications and observed benefits. C1 Brown Univ, Providence, RI 02912 USA. Jet Prop Lab, Pasadena, CA 91109 USA. Lawrence Livermore Natl Lab, Livermore, CA USA. RP Forsberg, A (reprint author), Brown Univ, Providence, RI 02912 USA. EM asf@cs.brown.edu; prabhat@cs.brown.edu; ghaley@cs.brown.edu; Andrew_Bragdon@brown.edu; joseph_levy@brown.edu; Caleb_Fassett@brown.edu; David_Shean@brown.edu; James_Head@brown.edu; Sarah.M.Milkovich@jpl.nasa; duchaine@llnl.gov OI Shean, David/0000-0003-3840-3860; Fassett, Caleb/0000-0001-9155-3804 NR 19 TC 5 Z9 5 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0272-1716 EI 1558-1756 J9 IEEE COMPUT GRAPH JI IEEE Comput. Graph. Appl. PD JUL-AUG PY 2006 VL 26 IS 4 BP 46 EP 54 DI 10.1109/MCG.2006.73 PG 9 WC Computer Science, Software Engineering SC Computer Science GA 059VQ UT WOS:000238760700010 PM 16863097 ER PT J AU Lee, J Yang, P Dessler, AE Platnick, S AF Lee, Joonsuk Yang, Ping Dessler, Andrew E. Platnick, Steven TI The influence of thermodynamic phase on the retrieval of mixed-phase cloud microphysical and optical properties in the visible and near-infrared region SO IEEE GEOSCIENCE AND REMOTE SENSING LETTERS LA English DT Article DE effective particle size; mixed-phase clouds; optical thickness; remote sensing ID SOLAR-RADIATION MEASUREMENTS; CIRRUS CLOUDS; LIQUID WATER; ICE CRYSTALS; THICKNESS; PARAMETERIZATION; REFLECTANCE; SCATTERING; MODELS; RADIUS AB Cloud microphysical and optical properties are inferred from the bidirectional reflectances simulated for a single-layered cloud consisting of an external mixture of ice particles and liquid droplets. The reflectances are calculated with a rigorous discrete ordinates radiative transfer model and are functions of the cloud effective particle size, the cloud optical thickness, and the values of the ice fraction in the cloud (Le. the ratio of ice water content to total water content). In the present light scattering and radiative transfer simulations, the ice fraction is assumed to be vertically homogeneous; the habit (shape) percentage as a function of ice particle size is consistent with that used for the Moderate Resolution Imaging Spectroradiometer (MODIS) operational (Collection 4 and earlier) cloud products; and the surface is assumed to be Lambertian with an albedo of 0.03. Furthermore, error analyses are performed that pertain to the inference of the mixed-phase cloud effective particle size and optical thickness. Errors are calculated with respect to the assumption of a cloud containing solely liquid or ice phase particles. The analyses suggest that the effective particle size inferred for a mixed-phase cloud can be underestimated (or overestimated) if pure liquid phase (or pure ice phase) is assumed for the cloud, whereas the corresponding cloud optical thickness can be overestimated (or underestimated). C1 Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. NASA, Langley Res Ctr, Sci Directorate, Hampton, VA 23681 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Lee, J (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; Platnick, Steven/J-9982-2014; Dessler, Andrew/G-8852-2012 OI Baum, Bryan/0000-0002-7193-2767; Platnick, Steven/0000-0003-3964-3567; Dessler, Andrew/0000-0003-3939-4820 NR 24 TC 6 Z9 6 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1545-598X J9 IEEE GEOSCI REMOTE S JI IEEE Geosci. Remote Sens. Lett. PD JUL PY 2006 VL 3 IS 3 BP 287 EP 291 DI 10.1109/LGRS.2006.864374 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 066XA UT WOS:000239262600001 ER PT J AU Satheesh, SK Deepshikha, S Srinivasan, J Kaufman, YJ AF Satheesh, S. K. Deepshikha, S. Srinivasan, J. Kaufman, Y. J. TI Large dust absorption of infrared radiation over Afro-Asian regions: Evidence for anthropogenic impact SO IEEE GEOSCIENCE AND REMOTE SENSING LETTERS LA English DT Article DE aerosols; anthropogenic impact; radiation ID SATELLITE; LAND AB There is a large uncertainty in the estimation of dust radiative forcing due to the lack of adequate data about complex spatial and temporal pattern of the radiative properties of dust. Here, we examine the temporal and spatial variability of dust absorption in the thermal infrared over the Afro-Asian regions using satellite data. Large dust absorption (nearly double compared to that of pure dust) was observed in regions with large anthropogenic influence, possibly due to deposition of black carbon on dust particles. While most of the recent estimates of global mean dust radiative forcing predicted net cooling, our studies indicate that there could be large heating due to dust over vast Afro-Asian regions. It appears that large dust heating is due to its interaction with anthropogenic black carbon. C1 Indian Inst Sci, Ctr Atmospher & Ocean Sci, Bangalore 560012, Karnataka, India. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RP Satheesh, SK (reprint author), Indian Inst Sci, Ctr Atmospher & Ocean Sci, Bangalore 560012, Karnataka, India. EM satheesh@caos.iisc.ernet.in NR 11 TC 8 Z9 8 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1545-598X J9 IEEE GEOSCI REMOTE S JI IEEE Geosci. Remote Sens. Lett. PD JUL PY 2006 VL 3 IS 3 BP 307 EP 311 DI 10.1109/LGRS.2006.869988 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 066XA UT WOS:000239262600005 ER PT J AU Tedesco, M Wang, JR AF Tedesco, Marco Wang, James R. TI Atmospheric correction of AMSR-E brightness temperatures for dry snow cover mapping SO IEEE GEOSCIENCE AND REMOTE SENSING LETTERS LA English DT Article DE atmospheric correction; microwave; remote sensing; snow ID RETRIEVAL; DEPTH AB Differences between the brightness temperatures (spectral gradient) collected by the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) at 18.7 and 36.5 GHz are used to map the snow-covered area (SCA) over a region including the western U.S. The brightness temperatures are corrected to take into account for atmospheric effects by means of a simplified radiative transfer equation whose parameters are stratified using rawinsonde data collected from a few stations. The surface emissivity is estimated from the model, and the brightness temperatures at the surface are computed as the product of the surface temperature and the computed emissivity. The SCA derived from microwave data is compared with that obtained from the Moderate Resolution Imaging Spectroradiometer for both cases of corrected and noncorrected brightness temperatures. The improvement to the SCA retrievals based on the corrected brightness temperatures shows an average value around 7%. C1 Univ Maryland Baltimore Cty, Goddad Earth Sci & Technol Ctr, Catonsville, MD 21228 USA. NASA, Goddard Space Flight Ctr, Hydrospher & Biospher Proc Lab, Greenbelt, MD 20771 USA. RP Tedesco, M (reprint author), Univ Maryland Baltimore Cty, Goddad Earth Sci & Technol Ctr, Catonsville, MD 21228 USA. EM mtedesco@umbc.edu RI Tedesco, Marco/F-7986-2015 NR 12 TC 15 Z9 16 U1 3 U2 8 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1545-598X J9 IEEE GEOSCI REMOTE S JI IEEE Geosci. Remote Sens. Lett. PD JUL PY 2006 VL 3 IS 3 BP 320 EP 324 DI 10.1109/LGRS.2006.871744 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 066XA UT WOS:000239262600008 ER PT J AU Tanelli, S Durden, SL Im, E AF Tanelli, Simone Durden, Stephen L. Im, Eastwood TI Simultaneous measurements of Ku- and Ka-band sea surface cross sections by an airborne radar SO IEEE GEOSCIENCE AND REMOTE SENSING LETTERS LA English DT Article DE radar; sea surface ID MEASURING MISSION TRMM; PRECIPITATION RADAR; OCEAN; MODEL; BACKSCATTER; SLOPE AB The dual-frequency Airborne. Precipitation Radar-2 (APR-2) was deployed during the Wakasa Bay Experiment in 2003, for validation of the Advanced Microwave Scanning Radiometer-EOS. Besides providing extensive observations, of diverse precipitating systems, this Ku-(13.4 GHz) and Ka-band (35.6 GHz) cross-track scanning radar measured se a surface backscatter simultaneously. While the characteristics of the normalized sea surface cross section sigma(o) at Ku-band are well understood and widely published, the existing experimental data concerning sigma(o) at Ka-band are scarce and results are inconsistent. In this letter, the Ku/Ka-band sigma(o) measurements collected by APR-2, together with the estimated uncertainties, are discussed. In general, the measured sigma(o) at Ka-band at around 10 degrees incidence angle appears to be close to that at Ku-band sigma(o), and Ka-band exhibits a nonnegligible difference in wind dependence with respect to Ku-band for moderate to high winds. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tanelli, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM simone.tanelli@jpl.nasa.gov NR 17 TC 30 Z9 30 U1 1 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1545-598X J9 IEEE GEOSCI REMOTE S JI IEEE Geosci. Remote Sens. Lett. PD JUL PY 2006 VL 3 IS 3 BP 359 EP 363 DI 10.1109/LGRS.2006.872929 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 066XA UT WOS:000239262600016 ER PT J AU Chien, S Doyle, R Davies, AG Jonsson, A Lorenz, R AF Chien, Steve Doyle, Richard Davies, Ashley Gerard Jonsson, Ari Lorenz, Ralph TI The future of AI in space SO IEEE INTELLIGENT SYSTEMS LA English DT Editorial Material ID VOLCANISM; SYSTEM C1 Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Ames Res Inst Adv Comp Sci, Moffett Field, CA 94035 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RP Chien, S (reprint author), Jet Prop Lab, Pasadena, CA 91109 USA. EM steve.chien@jpl.nasa.gov; richard.doyle@jpl.nasa.gov; ashley.davies@jpl.nasa.gov; jonsson@ptolemy.arc.nasa.gov; rlorenz@lpl.arizona.edu RI Lorenz, Ralph/B-8759-2016 OI Lorenz, Ralph/0000-0001-8528-4644 NR 13 TC 6 Z9 7 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1541-1672 J9 IEEE INTELL SYST JI IEEE Intell. Syst. PD JUL-AUG PY 2006 VL 21 IS 4 BP 64 EP 69 DI 10.1109/MIS.2006.79 PG 6 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 068PE UT WOS:000239386100014 ER PT J AU Menzies, T Hihn, J AF Menzies, T Hihn, J TI Evidence-based cost estimation for better-quality software SO IEEE SOFTWARE LA English DT Editorial Material C1 W Virginia Univ, Lane Dept Comp Sci, Morgantown, WV 26506 USA. Jet Prop Lab, Pasadena, CA 91109 USA. RP Menzies, T (reprint author), W Virginia Univ, Lane Dept Comp Sci, Morgantown, WV 26506 USA. EM tim@menzies.us; jairus.hihn@jpl.nasa.gov NR 0 TC 5 Z9 5 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0740-7459 J9 IEEE SOFTWARE JI IEEE Softw. PD JUL-AUG PY 2006 VL 23 IS 4 BP 64 EP 66 PG 3 WC Computer Science, Software Engineering SC Computer Science GA 059VN UT WOS:000238760400017 ER PT J AU Simon, MK Alouini, MS AF Simon, M. K. Alouini, M. -S. TI On the difference of two chi-square variates with application to outage probability computation (vol 49, pg 1946, 2001) SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Correction C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Texas A&M Qatar, Doha, Qatar. RP Simon, MK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM marvin.k.simon@jpl.nasa.gov; alouini@qatar.tamu.edu NR 2 TC 2 Z9 2 U1 0 U2 1 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 JUL PY 2006 VL 54 IS 7 BP 1346 EP 1347 DI 10.1109/TCOMM.2006.877960 PG 2 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 068WV UT WOS:000239406200026 ER PT J AU Morisette, JT Baret, F Liang, SL AF Morisette, Jeffrey T. Baret, Frederic Liang, Shunlin TI Special issue on global land product validation SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Editorial Material C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. INRA, CSE Agroparc, F-84914 Avignon, France. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. RP Morisette, JT (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. RI liang, shunlin/C-2809-2015; Baret, Fred/C-4135-2011 OI Baret, Fred/0000-0002-7655-8997 NR 4 TC 13 Z9 13 U1 2 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 JUL PY 2006 VL 44 IS 7 BP 1695 EP 1697 DI 10.1109/TGRS.2006.877436 PN 1 PG 3 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 061IJ UT WOS:000238864700001 ER PT J AU Abdou, WA Pilorz, SH Helmlinger, MC Conel, JE Diner, DJ Bruegge, CJ Martonchik, JV Gatebe, CK King, MD Hobbs, PV AF Abdou, Wedad A. Pilorz, Stuart H. Helmlinger, Mark C. Conel, James E. Diner, David J. Bruegge, Carol J. Martonchik, John V. Gatebe, Charles K. King, Michael D. Hobbs, Peter V. TI Sua Pan surface bidirectional reflectance: A case study to evaluate the effect of atmospheric correction on the surface products of the Multi-angle Imaging SpectroRadiometer (MISR) during SAFARI 2000 SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE aerosols; bidirectional reflectance function (BRF); remote sensing; surface ID AIRBORNE SPECTRAL MEASUREMENTS; AEROSOL; RETRIEVAL; LAND; ANISOTROPY; RADIOMETER; RADIANCE; MODEL; SKY AB This paper presents a validation case study of Multi-angle Imaging SpectroRadiometer (MISR) surface products where its bidirectional reflectance (BRF) measurements during the Southern Africa Regional Science Initiative (SAFARI 2000) campaign are compared with those coincidently evaluated on the ground and from the air, using the Portable Apparatus for Rapid Acquisition of Bidirectional Observations of Land and Atmosphere (PARABOLA) and Cloud Absorption Radiometer observations. respectively. The presence of haze and smoke during the campaign provided a case study to evaluate the effect of atmospheric correction on MISR surface products. Two surface types were considered in the analyses: the bright desert-like surface of the Pan and the dark grassland that surrounds it. The results show that for the dark surface the BRF values retrieved from MISR are in good agreement, within 5%, with those obtained from field data. For the bright desert-like pan surface, better agreement, within similar to 10%, was found in all channels on the clear day but only in the forward scattering on the hazy day. A comparison of MISR aerosol retrievals to those obtained from three independent ground measurements suggests that, in the presence of a highly reflective surface, small uncertainties in the MISR aerosol retrievals become magnified at larger optical depths, causing errors in the surface BRF retrievals. C1 CALTECH, Jet Prop Lab, Div Earth Sci, Pasadena, CA 91109 USA. Univ Maryland, Goddard Earth Sci & Technol Ctr, Catonsville, MD 21228 USA. NASA, Goddard Space Flight Ctr, Earth Sun Explorat Div, Greenbelt, MD 20771 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. RP Abdou, WA (reprint author), CALTECH, Jet Prop Lab, Div Earth Sci, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM wedad.abdou@jpl.nasa.gov RI King, Michael/C-7153-2011; Gatebe, Charles/G-7094-2011 OI King, Michael/0000-0003-2645-7298; Gatebe, Charles/0000-0001-9261-2239 NR 28 TC 9 Z9 10 U1 1 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 EI 1558-0644 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 2006 VL 44 IS 7 BP 1699 EP 1706 DI 10.1109/TGRS.2006.876031 PN 1 PG 8 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 061IJ UT WOS:000238864700002 ER PT J AU Lyapustin, A Wang, Y Martonchik, J Privette, JL Holben, B Slutsker, I Sinyuk, A Smirnov, A AF Lyapustin, Alexei Wang, Yujie Martonchik, John Privette, Jeffrey L. Holben, Brent Slutsker, Ilya Sinyuk, Alexander Smirnov, Alexander TI Local analysis of MISR surface BRF and albedo over GSFC and Mongu AERONET sites SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE Aerosol Robotic Network (AERONET); albedo; atmospheric correction; bidirectional reflectance; Multiangle Imaging SpectroRadiometer (MISR); validation ID RADIATIVE-TRANSFER PROBLEM; AEROSOL OPTICAL-PROPERTIES; SKY RADIANCE MEASUREMENTS; NON-LAMBERTIAN SURFACE; GREENS-FUNCTION METHOD; RETRIEVAL; ALGORITHMS; PRODUCTS; NETWORK; MODIS AB We have developed an atmospheric correction algorithm to retrieve the surface bidirectional reflectance factor (BRF) and albedo from Multiangle Imaging SpectroRadiometer (MISR) measurements for small areas around Aerosol Robotic Network (AERONET) sunphotometer sites, using AERONET aerosol and column water vapor information. Our goal is to develop an indirect validation method for MISR surface reflectance products over heterogeneous land. Our algorithm makes independent retrievals with both the Li Sparse-Ross Thick kernel BRF model and the modified Rahman-Pinty-Verstraete BRF model used in the Moderate Resolution Imaging Spectroradiometer and MISR land algorithms, respectively. In this study, we report the first results of processing MISR Collection 4 data for 2003-2004 for two sites, Mongu, Zambia, and Greenbelt, MD. We found that MISR generally provides accurate retrievals of BRF and albedo in both clear and hazy atmospheric conditions, correctly reproducing the parameter time series and spatial distribution. We found that the MISR BRF, on average, is less anisotropic in the visible bands. The difference is greatest in the blue band, but decreases with increasing wavelength such that it is negligible in the near-IR band. This discrepancy originates in part in the MISR aerosol retrieval algorithm over heterogeneous land, which tends to select an aerosol model that favors spectrally invariant shapes of surface BRF. The other part of the discrepancy comes from the surface hemispherical-directional reflectance factor retrieval algorithm where the iteration loop that removes the diffuse atmospheric transmittance is currently turned off. Our initial results suggest that the MISR surface albedo is on average lower than our retrievals by about 0.005 in the green and red bands. In the near-IR, it agreed with our retrievals with the modified Rahman-Pinty-Verstraete model for the Mongu site, but was systematically lower over the Greenbelt site by about 0.016. When significant aerosol absorption is present (Mongu), the albedo discrepancy is additionally biased by the difference between the MISR and AERONET retrievals of aerosol absorption. C1 Univ Maryland, GEST, Catonsville, MD 21228 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. RP Lyapustin, A (reprint author), Univ Maryland, GEST, Catonsville, MD 21228 USA. RI Smirnov, Alexander/C-2121-2009; Privette, Jeffrey/G-7807-2011; Lyapustin, Alexei/H-9924-2014 OI Smirnov, Alexander/0000-0002-8208-1304; Privette, Jeffrey/0000-0001-8267-9894; Lyapustin, Alexei/0000-0003-1105-5739 NR 22 TC 15 Z9 15 U1 0 U2 4 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 JUL PY 2006 VL 44 IS 7 BP 1707 EP 1718 DI 10.1109/TGRS.2005.856678 PN 1 PG 12 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 061IJ UT WOS:000238864700003 ER PT J AU Salomonson, VV Appel, I AF Salomonson, V. V. Appel, Igor TI Development of the Aqua MODIS NDSI fractional snow cover algorithm and validation results SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE Aqua mission; Earth Observing System (EOS); fractional snow cover; ground truth; Landsat; Moderate Resolution Imaging Spectroradiometer (MODIS); pixel; snow cover; Terra mission ID PRODUCTS AB The principal purpose of this paper is to describe the development and validation of an algorithm to estimate the fraction of snow cover within a 500-m pixel of the Moderate Resolution Imaging Spectroradiometer (MODIS) operating on the Earth Observing System Aqua spacecraft. The performance of this algorithm and algorithms applicable to the MODIS on the Terra spacecraft are compared. Validation efforts show that both pixel-level, fractional snow cover relationships for the Terra and Aqua MODIS instruments work well as quantified by such measures as correlation coefficient (r) and root-mean-square error when compared to Landat-7 Enhanced Thematic Mapper ground-truth observations covering a substantial range of snow cover conditions. Over all the scenes used herein, the correlation coefficients were near 0.9 and the RMSE near 0.10. However, somewhat better performance was found for the Terra MODIS versus the Aqua MODIS over nearly concurrently observed scenes. Furthermore, it is clear that more improvements in fractional snow cover estimates within MODIS pixels should be pursued to better account for variability in slope and aspect, atmospheric effects, snow cover types, and land cover. C1 NASA, Goddard Space Flight Ctr, Earth Sun Div, Greenbelt, MD 20715 USA. RP Salomonson, VV (reprint author), NASA, Goddard Space Flight Ctr, Earth Sun Div, Greenbelt, MD 20715 USA. RI Appel, Igor/E-7940-2011 OI Appel, Igor/0000-0003-0907-3807 NR 9 TC 87 Z9 93 U1 3 U2 21 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 JUL PY 2006 VL 44 IS 7 BP 1747 EP 1756 DI 10.1109/TGRS.2006.876029 PN 1 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 061IJ UT WOS:000238864700007 ER PT J AU Brown, ME Pinzon, JE Didan, K Morisette, JT Tucker, CJ AF Brown, Molly E. Pinzon, Jorge E. Didan, Kamel T Morisette, Jeffrey Tucker, Compton J. TI Evaluation of the consistency of long-term NDVI time series derived from AVHRR, SPOT-Vegetation, SeaWiFS, MODIS, and Landsat ETM+ sensors SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE Advanced Very High Resolution Radiometer (AVHRR); Moderate Resolution Imaging Spectroradiometer (MODIS); SPOT; vegetation ID SURFACE REFLECTANCE; LEAF-AREA; CLIMATE; INDEXES; VALIDATION; FORECAST; PRODUCTS; DATASET; AFRICA; FOREST AB This paper evaluates the consistency of the Normalized Difference Vegetation Index (NDVI) records derived from Advanced Very High Resolution Radiometer (AVHRR), SPOT-Vegetation, SeaWiFS, Moderate Resolution Imaging Spectroradiometer, and Landsat ETM+. We used independently derived NDVI from atmospherically corrected ETM+ data at 13 Earth Observation System Land Validation core sites, eight locations of drought, and globally aggregated one-degree data from the four coarse resolution sensors to assess the NDVI records agreement. The objectives of this paper are to: 1) compare the absolute and relative differences of the vegetation signal across these sensors from a user perspective, and, to a lesser degree, 2) evaluate the possibility of merging the AVHRR historical data record with that of the more modern sensors in order to provide historical perspective on current vegetation activities. The statistical and correlation analyses demonstrate that due to the similarity in their overall variance, it is not necessary to choose between the longer time series of AVHRR and the higher quality of the more modern sensors. The long-term AVHRR-NDVI record provides a critical historical perspective on vegetation activities necessary for global change research and, thus, should be the basis of an intercalibrated, sensor-independent NDVI data record. This paper suggests that continuity is achievable given the similarity between these datasets. C1 NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. Univ Arizona, TBRS Lab Soil Water & Environm Sci, Tucson, AZ 85721 USA. RP Brown, ME (reprint author), NASA, Goddard Space Flight Ctr, SSAI, Code 661, Greenbelt, MD 20771 USA. EM molly.brown@gsfc.nasa.gov RI Brown, Molly/E-2724-2010; Brown, Molly/M-5146-2013 OI Brown, Molly/0000-0001-7384-3314; Brown, Molly/0000-0001-7384-3314 NR 45 TC 162 Z9 174 U1 3 U2 75 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 JUL PY 2006 VL 44 IS 7 BP 1787 EP 1793 DI 10.1109/TGRS.2005.860205 PN 1 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 061IJ UT WOS:000238864700011 ER PT J AU Baret, F Morissette, JT Fernandes, RA Champeaux, JL Myneni, RB Chen, J Plummer, S Weiss, M Bacour, C Garrigues, S Nickeson, JE AF Baret, Frederic Morissette, Jeffrey T. Fernandes, Richard A. Champeaux, J. L. Myneni, Ranga B. Chen, J. Plummer, Stephen Weiss, M. Bacour, C. Garrigues, Sebastien Nickeson, Jamie E. TI Evaluation of the representativeness of networks of sites for the global validation and intercomparison of land biophysical products: Proposition of the CEOS-BELMANIP SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE global land biophysical products; intercomparison; leaf area index (LAI); validation ID LEAF-AREA; RESOLUTION; COVER; INVERSION; DATABASE; SURFACE; MODIS; MODEL AB This study investigates the representativeness of land cover and leaf area index (LAI) sampled by a global network of sites to be used for the evaluation of land biophysical products, such as LAI or fAPAR, derived from current satellite systems. The networks of sites considered include 100 sites where ground measurements of LAI or fAPAR have been performed for the validation of medium resolution satellite land biophysical products, 188 FLUXNET sites and 52 AERONET sites. All the sites retained had less than 25% of water bodies within a 8 x 8 km(2) window, and were separated by more than 20 km. The ECOCLIMAP global classification was used to quantify the representativeness of the networks. It allowed describing the Earth's surface with seven main types and proposed a climatology for monthly LAI values at a spatial resolution around 1 km. The site distribution indicates a large over representation of the northern midlatitudes; relative to other regions, and an under-representation of bare surfaces, grass, and evergreen broadleaf forests. These three networks represent all together 295 sites after elimination of sites that were too close. They were thus completed by 76 additional sites to improve the representativeness in latitude, longitude, and surface type. This constitutes the BELMANIP network proposed as a benchmark for intercomparison of land biophysical products. Suitable approaches to conducting intercomparison at the sites are recommended. C1 INRA, CSE, F-84914 Avignon, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Canada Ctr Remote Sensing, Ottawa, ON K1A 0Y7, Canada. METEO FRANCE, Ctr Natl Rech Mitiorol, F-31057 Toulouse, France. Boston Univ, Boston, MA 02215 USA. Univ Toronto, Toronto, ON M5S 3G3, Canada. European Space Agcy, Int Geosphere Biosphere Programme, I-00044 Frascati, Italy. Sci Syst & Applicat Incorp, Lanham, MD 20706 USA. RP Baret, F (reprint author), INRA, CSE, F-84914 Avignon, France. EM baret@avignon.inra.fr RI Myneni, Ranga/F-5129-2012; Baret, Fred/C-4135-2011; OI Baret, Fred/0000-0002-7655-8997; Weiss, Marie/0000-0002-2341-667X NR 31 TC 88 Z9 94 U1 3 U2 25 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 JUL PY 2006 VL 44 IS 7 BP 1794 EP 1803 DI 10.1109/TGRS.2006.876030 PN 1 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 061IJ UT WOS:000238864700012 ER PT J AU Morisette, JT Baret, F Privette, JL Myneni, RB Nickeson, JE Garrigues, S Shabanov, NV Weiss, M Fernandes, RA Leblanc, SG Kalacska, M Sanchez-Azofeifa, GA Chubey, M Rivard, B Stenberg, P Rautiainen, M Voipio, P Manninen, T Pilant, AN Lewis, TE Iiames, JS Colombo, R Meroni, M Busetto, L Cohen, WB Turner, DP Warner, ED Petersen, GW Seufert, G Cook, R AF Morisette, Jeffrey T. Baret, Frederic Privette, Jeffrey L. Myneni, Ranga B. Nickeson, Jaime E. Garrigues, Sebastien Shabanov, Nikolay V. Weiss, Marie Fernandes, Richard A. Leblanc, Sylvain G. Kalacska, Margaret Sanchez-Azofeifa, G. Arturo Chubey, Michael Rivard, Benoit Stenberg, Pauline Rautiainen, Miina Voipio, Pekka Manninen, Terhikki Pilant, Andrew N. Lewis, Timothy E. Iiames, John S. Colombo, Roberto Meroni, Michele Busetto, Lorenzo Cohen, Warren B. Turner, David P. Warner, Eric D. Petersen, G. W. Seufert, Guenter Cook, Robert TI Validation of global moderate-resolution LAI products: A framework proposed within the CEOS Land Product Validation subgroup SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE Committee on Earth Observing Satellites (CEOS); leaf area index (LAI); validation ID LEAF-AREA INDEX; LIGHT-INTERCEPTION EFFICIENCY; NET PRIMARY PRODUCTION; HEMISPHERICAL PHOTOGRAPHY; SATELLITE IMAGERY; BOREAL FORESTS; ABSORBED PAR; SIMPLE RATIO; SURFACE; PARAMETERS AB Initiated in 1984, the Committee Earth Observing Satellites' Working Group on Calibration and Validation (CEOS WGCV) pursues activities to coordinate, standardize and advance calibration and validation of civilian satellites and their data. One subgroup of CEOS WGCV, Land Product Validation (LPV), was established in 2000 to define standard validation guidelines and protocols and to foster data and information exchange relevant to the validation of land products. Since then, a number of leaf area index (LAI) products have become available to the science community at both global and regional extents. Having multiple global LAI products and multiple, disparate validation activities related to these products presents the opportunity to realize efficiency through international collaboration. So the LPV subgroup established an international LAI intercomparison validation activity. This paper describes the main components of this international validation effort. The paper documents the current participants, their ground LAI measurements and scaling techniques, and the metadata and infrastructure established to share data. The paper concludes by describing plans for sharing both field data and high-resolution LAI products from each site. Many considerations of this global LAI intercomparison can apply to other products, and this paper presents a framework for such collaboration. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. INRA, CSE, F-84914 Avignon, France. Boston Univ, Boston, MA 02215 USA. Sci Syst & Applicat Incorp, Lanham, MD 20706 USA. Univ Maryland, Earth Syst Sci Interdisplinary Ctr, College Pk, MD 20742 USA. Canada Ctr Remote Sensing, Ottawa, ON K1A 0Y7, Canada. Univ Alberta, EOSL, Dept Earth & Atmospher Sci, Edmonton, AB T6G 2E3, Canada. Univ Helsinki, Dept Forest Ecol, FIN-00014 Helsinki, Finland. Finnish Forest Res Inst, Suonenjoki Res Stn, FIN-77600 Suonenjoki, Finland. Finnish Meteorol Inst, FIN-00191 Helsinki, Finland. US EPA, Res Triangle Pk, NC 27711 USA. Univ Milan, Dipartimento Sci Ambiente & Terr, Lab Telerilevamento, I-20126 Milan, Italy. US Forest Serv, Corvallis Forestry Sci Lab, Corvallis, OR 97331 USA. Oregon State Univ, Corvallis, OR 97331 USA. Penn State Univ, University Pk, PA 16802 USA. Joint Res Ctr Inst Environm & Sustainabil, Climate Change Unit, Ispra, Italy. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Morisette, JT (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM jeff.morisette@nasa.gov RI Rautiainen, Miina/A-4208-2009; Meroni, Michele/F-2363-2010; Privette, Jeffrey/G-7807-2011; Busetto, Lorenzo/M-1600-2014; Myneni, Ranga/F-5129-2012; Seufert, Gunther/J-9918-2013; Baret, Fred/C-4135-2011; OI Rautiainen, Miina/0000-0002-6568-3258; Privette, Jeffrey/0000-0001-8267-9894; Busetto, Lorenzo/0000-0001-9634-6038; Seufert, Gunther/0000-0002-6019-6688; Baret, Fred/0000-0002-7655-8997; Kalacska, Margaret/0000-0002-1676-481X; Weiss, Marie/0000-0002-2341-667X; Cook, Robert/0000-0001-7393-7302 NR 73 TC 192 Z9 209 U1 7 U2 47 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 JUL PY 2006 VL 44 IS 7 BP 1804 EP 1817 DI 10.1109/TGRS.2006.872529 PN 1 PG 14 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 061IJ UT WOS:000238864700013 ER PT J AU Yang, WZ Huang, D Tan, B Stroeve, JC Shabanov, NV Knyazikhin, Y Nemani, RR Myneni, RB AF Yang, Wenze Huang, Dong Tan, Bin Stroeve, Julienne C. Shabanov, Nikolay V. Knyazikhin, Yuri Nemani, Ramakrishna R. Myneni, Ranga B. TI Analysis of leaf area index and fraction of PAR absorbed by vegetation products from the terra MODIS sensor: 2000-2005 SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE evaluation and assessment; Fraction of Photosynthetically Active Radiation (FPAR) absorbed by vegetation; Leaf Area Index (LAI); Moderate Resolution Imaging Spectroradiometer (MODIS) ID PHOTOSYNTHETICALLY ACTIVE RADIATION; LAI PRODUCT; MULTISCALE ANALYSIS; FPAR ALGORITHM; MISR DATA; VALIDATION; ATMOSPHERE; CANOPIES; COVER AB The analysis of two years of Collection 3 and five years of Collection 4 Terra Moderate Resolution Imaging Spectroradiometer (MODIS) Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) data sets is presented in this article with the goal of understanding product quality with respect to version (Collection 3 versus 4), algorithm (main versus backup), snow (snow-free versus snow on the ground), and cloud (cloud-free versus cloudy) conditions. Retrievals from the main radiative transfer algorithm increased from 55% in Collection 3 to 67% in Collection 4 due to algorithm refinements and improved inputs. Anomalously high LAI/FPAR values observed in Collection 3 product in some vegetation types were corrected in Collection 4. The problem of reflectance saturation and too few main algorithm retrievals in broadleaf forests persisted in Collection 4. The spurious seasonality in needleleaf LAI/FPAR fields was traced to fewer reliable input data and retrievals during the boreal winter period. About 97% of the snow covered pixels were processed by the backup Normalized Difference Vegetation Index-based algorithm. Similarly, a majority of retrievals under cloudy conditions were obtained from the backup algorithm. For these reasons, the users are advised to consult the quality flags accompanying the LAI and FPAR product. C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. Univ Colorado, Natl Snow & Ice Data Ctr, Boulder, CO 80309 USA. NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Moffett Field, CA 94035 USA. RP Yang, WZ (reprint author), Boston Univ, Dept Geog, Boston, MA 02215 USA. EM ywze@crsa.bu.edu RI Stroeve, Julienne/D-1525-2010; Yang, Wenze/B-8356-2012; Tan, Bin/G-1331-2012; Huang, Dong/H-7318-2014; Myneni, Ranga/F-5129-2012 OI Yang, Wenze/0000-0001-8514-2742; Huang, Dong/0000-0001-9715-6922; NR 26 TC 92 Z9 97 U1 4 U2 22 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 JUL PY 2006 VL 44 IS 7 BP 1829 EP 1842 DI 10.1109/TGRS.2006.871214 PN 1 PG 14 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 061IJ UT WOS:000238864700015 ER PT J AU Yang, WZ Tan, B Huang, D Rautiainen, M Shabanov, NV Wang, Y Privette, JL Huemmrich, KF Fensholt, R Sandholt, I Weiss, M Ahl, DE Gower, ST Nemani, RR Knyazikhin, Y Myneni, RB AF Yang, Wenze Tan, Bin Huang, Dong Rautiainen, Miina Shabanov, Nikolay V. Wang, Y. Privette, Jeffrey L. Huemmrich, Karl Fred Fensholt, Rasmus Sandholt, Inge Weiss, M. Ahl, Douglas E. Gower, Stith T. Nemani, Ramakrishna R. Knyazikhin, Yuri Myneni, Ranga B. TI MODIS leaf area index products: From validation to algorithm improvement SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE Fraction of Photosynthetically Active Radiation (FPAR) absorbed by vegetation; Leaf Area Index (LAI); Moderate Resolution Imaging Spectroradiometer (MODIS); validation ID LAI PRODUCT; MULTISCALE ANALYSIS; KALAHARI; VARIABLES; FORESTS; AFRICA AB Global products of vegetation green Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation absorbed by vegetation (FPAR) are being operationally produced from Terra and Aqua Moderate Resolution Imaging Spectroradiometers (MODIS) at 1-km resolution and eight-day frequency. This paper summarizes the experience of several collaborating investigators on validation of MODIS LAI products and demonstrates the close connection between product validation and algorithm refinement activities. The validation of moderate resolution LAI products includes three steps: 1) field sampling representative of LAI spatial distribution and dynamic range within each major land cover type at the validation site; 2) development of a transfer function between field LAI measurements and high resolution satellite data to generate a reference LAI map over an extended area; and 3) comparison of MODIS LAI with aggregated reference LAI map at patch (multipixel) scale in view of geo-location and pixel shift uncertainties. The MODIS LAI validation experiences, summarized here, suggest three key factors that influence the accuracy of LAI retrievals: 1) uncertainties in input land cover data, 2) uncertainties in input surface reflectances, and 3) uncertainties from the model used to build the look-up tables accompanying the algorithm. This strategy of validation efforts guiding algorithm refinements has led to progressively more accurate LAI products from the MODIS sensors aboard NASA's Terra and Aqua platforms. C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. Univ Helsinki, Dept Forest Ecol, FI-00014 Helsinki, Finland. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Catonsville, MD 20771 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Univ Copenhagen, Inst Geog, DK-1350 Copenhagen, Denmark. INRA, CSE, NOVELTIS, F-84014 Avignon, France. Univ Wisconsin, Dept Forest Ecol & Management, Madison, WI 53706 USA. NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Moffett Field, CA 94035 USA. RP Yang, WZ (reprint author), Boston Univ, Dept Geog, Boston, MA 02215 USA. EM ywze@crsa.bu.edu RI Rautiainen, Miina/A-4208-2009; Privette, Jeffrey/G-7807-2011; Yang, Wenze/B-8356-2012; Tan, Bin/G-1331-2012; Huang, Dong/H-7318-2014; Fensholt, Rasmus/L-7951-2014; Myneni, Ranga/F-5129-2012; OI Rautiainen, Miina/0000-0002-6568-3258; Privette, Jeffrey/0000-0001-8267-9894; Yang, Wenze/0000-0001-8514-2742; Huang, Dong/0000-0001-9715-6922; Fensholt, Rasmus/0000-0003-3067-4527; Weiss, Marie/0000-0002-2341-667X NR 29 TC 163 Z9 181 U1 2 U2 40 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 JUL PY 2006 VL 44 IS 7 BP 1885 EP 1898 DI 10.1109/TGRS.2006.871215 PN 1 PG 14 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 061IJ UT WOS:000238864700020 ER PT J AU Liu, Z Karam, LJ Watson, AB AF Liu, Z Karam, LJ Watson, AB TI JPEG2000 encoding with perceptual distortion control SO IEEE TRANSACTIONS ON IMAGE PROCESSING LA English DT Article DE distortion control; embedded coding; human visual system (HVS); JPEG2000; perception ID PATTERN-VISION MECHANISMS; PROBABILITY SUMMATION; MASKING; COMPRESSION; ADAPTATION; FREQUENCY; MODELS; FIELD AB In this paper, a new encoding approach is proposed to control the JPEG2000 encoding in order to reach a desired perceptual quality. The new method is based on a vision model that incorporates various masking effects of human visual perception and a perceptual distortion metric that takes spatial and spectral summation of individual quantization errors into account. Compared with the conventional rate-based distortion minimization JPEG2000 encoding, the new method provides a way to generate consistent quality images at a lower bit rate. C1 Qualcomm, San Diego, CA 92121 USA. Arizona State Univ, Dept Elect Engn, Tempe, AZ 85287 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Liu, Z (reprint author), Qualcomm, San Diego, CA 92121 USA. EM zhenl@qualcomm.com; karam@asu.edu; abwatson@mail.arc.nasa.gov NR 31 TC 82 Z9 83 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1057-7149 J9 IEEE T IMAGE PROCESS JI IEEE Trans. Image Process. PD JUL PY 2006 VL 15 IS 7 BP 1763 EP 1778 DI 10.1109/TIP.2006.873460 PG 16 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 059DT UT WOS:000238714200006 PM 16830900 ER PT J AU Cruden, BA Cassell, AM AF Cruden, Brett A. Cassell, Alan M. TI Vertically oriented carbon nanofiber based nanoelectromechanical switch SO IEEE TRANSACTIONS ON NANOTECHNOLOGY LA English DT Article DE carbon nanotubes; microelectromechanical systems; programmable circuits; relays; switches ID NANOTUBE TRANSISTORS; LOGIC GATES; PLASMA; MICROELECTRONICS; GROWTH AB We present a proof-of-principle study of a vertically aligned carbon nanofiber switch and study relevant parameters via a model for a static switch. Vertically aligned freestanding carbon nanofibers are produced by plasma-enhanced chemical vapor deposition (PECVD) and their deflection. under applied voltage is measured using an optical microscope. The deflection is compared with a static force balance model, which successfully predicts the switching behavior assuming a nanofiber modulus of 40 GPa, which is consistent with independent modulus measurements made in our laboratory. The model is then extended to explore constraints for implementing a vertically aligned nanotube switch into present CMOS process flow. Carbon nanofibers of less than 40 nm in diameter, which may be grown by current PECVD technology, are shown to be acceptable for device integration for current and future CMOS scaling. To accommodate varying tube sizes and architectures, a basic scaling relationship is developed to relate CMOS via parameters and nanofiber characteristics to programming voltage. C1 NASA, Ames Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Cruden, BA (reprint author), NASA, Ames Ctr Nanotechnol, Moffett Field, CA 94035 USA. EM bcruden@mail.arc.nasa.gov NR 26 TC 8 Z9 8 U1 1 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1536-125X EI 1941-0085 J9 IEEE T NANOTECHNOL JI IEEE Trans. Nanotechnol. PD JUL PY 2006 VL 5 IS 4 BP 350 EP 355 DI 10.1109/TNANO.2006.876923 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Science & Technology - Other Topics; Materials Science; Physics GA 065AT UT WOS:000239132500005 ER PT J AU Wheeler, KR Chang, MH Knuth, KH AF Wheeler, Kevin R. Chang, Mindy H. Knuth, Kevin H. TI Gesture-based control and EMG decomposition SO IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART C-APPLICATIONS AND REVIEWS LA English DT Article; Proceedings Paper CT IEEE International Workshop on Soft Computing in Industrial Applications CY JUN 23-25, 2003 CL BINGHAMTON, BINGHAMTON, NY SP IEEE Syst, Man & Cybernet Soc HO BINGHAMTON DE Bayesian decomposition; electromyogram (EMG); gesture recognition; hidden Markov model (HMM); motor unit action potential (MUAP) ID SURFACE MYOELECTRIC SIGNALS; ELECTROMYOGRAPHIC SIGNALS; SPEECH RECOGNITION; MODEL; ELECTRODE AB This paper presents two probabilistic developments for the use with electromyograms (EMGs). First described is a neuroelectric interface for virtual device control based on gesture recognition. The second development is a Bayesian method for decomposing EMGs into individual motor unit act,ion potentials (MUAPs). This Bayesian decomposition method allows for distinguishing individual muscle groups with the goal of enhancing gesture recognition. All examples presented rely upon sampling EMG data from a subject's forearm. The gesture-based recognition uses pattern recognition software that has been trained to identify gestures from among a given set of gestures. The pattern recognition software consists of bidden Markov models, which are used to recognize the gestures as they are being performed in real time from moving averages of EMGs. Two experiments were conducted to examine the feasibility of this interface technology. The first replicated a virtual joystick interface, and the second replicated a keyboard. Moving averages of EMGs do not provide an easy distinction between fine muscle groups. To better distinguish between different fine motor skill muscle groups, we present a Bayesian algorithm to separate surface EMGs into representative MUAPs. The algorithm is based on differential variable component analysis, which was originally developed for electroencephalograms. The algorithm uses a simple forward model representing a mixture of MUAPs as seen across multiple channels. The parameters of this model are iteratively optimized for each component. Results are presented on both synthetic and experimental EMG data. The synthetic case has additive white noise and is compared with known components. The experimental EMG data were obtained using a custom linear electrode array designed for this study. C1 NASA, Ames Res Ctr, Intelligent Syst Div, Moffett Field, CA 94035 USA. Stanford Univ, Dept Bioengn, Stanford, CA 94305 USA. SUNY Albany, Dept Phys, Albany, NY 12222 USA. RP Wheeler, KR (reprint author), Monterey Bay Aquarium Res Inst, Moss Landing, CA 95039 USA. EM kevinwheeler@ieee.org; mindyc@stanford.edu; kknuth@albany.edu NR 18 TC 15 Z9 16 U1 1 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1094-6977 J9 IEEE T SYST MAN CY C JI IEEE Trans. Syst. Man Cybern. Part C-Appl. Rev. PD JUL PY 2006 VL 36 IS 4 BP 503 EP 514 DI 10.1109/TSMCC.2006.875418 PG 12 WC Computer Science, Artificial Intelligence; Computer Science, Cybernetics; Computer Science, Interdisciplinary Applications SC Computer Science GA 059CP UT WOS:000238711200007 ER PT J AU Cho, EJ Pavlidis, D Zhao, GY Hubbard, SM Schwank, J AF Cho, Eunjung Pavlidis, Dimitris Zhao, Guangyuan Hubbard, Seth M. Schwank, Johannes TI Improvement of CO sensitivity in GaN-based gas sensors SO IEICE TRANSACTIONS ON ELECTRONICS LA English DT Article; Proceedings Paper CT 6th Topical Workshop on Heterostructure Microelectronics (TWHM 2005) CY AUG, 2005 CL Awaji Isl, JAPAN DE GaN; gas sensor; Pt Schottky diode; CO ID FIELD-EFFECT DEVICES; SCHOTTKY DIODES; HYDROGEN; GATES AB Pt Schottky diode gas sensors for carbon monoxide (CO) were fabricated using slightly Si doped bulk GaN grown on sapphire substrate. The influence of diode size, Pt thickness, operating temperature on gas sensitivity was investigated. CO sensitivity was improved six times by optimizing the size and thickness of the Pt contact. Surface restructuring and morphology changes of Pt film were observed after thermal annealing. These changes are enhanced as the film thickness is reduced further and contribute to improve CO sensitivity. C1 Tech Univ Darmstadt, Inst Microwave Engn, Dept High Frequency Elect, D-64283 Darmstadt, Germany. Univ Michigan, Dept Elect Engn & Comp Sci, Ann Arbor, MI 48109 USA. NASA, Glenn Res Ctr, Natl Res Council Associate, Cleveland, OH 44135 USA. Univ Michigan, Dept Chem Engn, Ann Arbor, MI 48109 USA. RP Cho, EJ (reprint author), Tech Univ Darmstadt, Inst Microwave Engn, Dept High Frequency Elect, Merckstr 25, D-64283 Darmstadt, Germany. EM cho@hf.tu-darmstadt.de RI Schwank, Johannes/A-8315-2013 NR 14 TC 2 Z9 2 U1 1 U2 7 PU IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG PI TOKYO PA KIKAI-SHINKO-KAIKAN BLDG, 3-5-8, SHIBA-KOEN, MINATO-KU, TOKYO, 105-0011, JAPAN SN 0916-8524 EI 1745-1353 J9 IEICE T ELECTRON JI IEICE Trans. Electron. PD JUL PY 2006 VL E89C IS 7 BP 1047 EP 1051 DI 10.1093/ietele/e89-c.7.1047 PG 5 WC Engineering, Electrical & Electronic SC Engineering GA 062RK UT WOS:000238962000029 ER PT J AU Weidman, PD Kubitschek, DG Davis, AMJ AF Weidman, P. D. Kubitschek, D. G. Davis, A. M. J. TI The effect of transpiration on self-similar boundary layer flow over moving surfaces SO INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE LA English DT Article DE similarity solutions; transpiration; nonuniqueness; stability ID REVERSE FLOW; WALL AB The simultaneous effects of normal transpiration through and tangential movement of a semi-infinite plate on self-similar boundary layer flow beneath a uniform free stream is considered. The flow is therefore governed by a plate velocity parameter lambda and a transpiration parameter mu and the computed wall shear stress parameter is f ''(0). Dual solutions are found for each value of mu in lambda - f ''(0) parameter space. It is shown that the range of known dual solutions for zero transpiration increases with suction and decreases with blowing. A stability analysis for this self-similar flow reveals that, for each value of mu, lower solution branches are unstable while upper solution branches are stable. (c) 2006 Elsevier Ltd. All rights reserved. C1 Univ Colorado, Dept Mech Engn, Boulder, CO 80309 USA. CALTECH, Jet Prop Lab, Opt Navigat Grp, Pasadena, CA 91109 USA. Univ Alabama, Dept Math, Tuscaloosa, AL 35487 USA. RP Weidman, PD (reprint author), Univ Colorado, Dept Mech Engn, Boulder, CO 80309 USA. EM weidman@colorado.edu NR 11 TC 204 Z9 206 U1 1 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7225 J9 INT J ENG SCI JI Int. J. Eng. Sci. PD JUL PY 2006 VL 44 IS 11-12 BP 730 EP 737 DI 10.1016/j.ijengsci.2006.04.005 PG 8 WC Engineering, Multidisciplinary SC Engineering GA 087RU UT WOS:000240760700004 ER PT J AU Berger, MH Sayir, A Berger, P AF Berger, MH Sayir, A Berger, P TI Microstructure, hydrogen distribution and electrical properties of melt grown high temperature protonic conductors SO INTERNATIONAL JOURNAL OF HYDROGEN ENERGY LA English DT Article DE high temperature protonic conductors; directional solidification; complex perovskite; cation ordering; hydrogen distribution ID COMPLEX PEROVSKITES; OXIDES AB A Sr-3(Ca1+xNb2-x)O9-delta High Temperature Protonic Conductor has been produced using the melt growth process with the aim of reducing the grain-boundary blocking effect in proton conduction. The microstructure is characteristic of a cellular growth with cell dimension of 10-20 mu m in width and 100 mu m in length. The cells have distinct core and shell regions. A composition gradient in bivalent to pentavalent cation ratio is observed from the core to the shell. The cores act as channels for hydrogen diffusion. Nano-scaled domains have been revealed inside the cells identified as domains of 1:1 order of the cations on the B sites and orientation variants in the oxygen octahedra tilting. Ion Beam Analyses using a Nuclear Microprobe reveal only a slight hydrolysis of the surface after heat treatment of 10 h at 500 degrees C in wet air. Protonic conductivity is discussed and improvements are suggested by optimizing the calcium to niobium ratio of the constituent elements and designing larger cells. (c) 2005 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved. C1 Ecole Mine Paris, Ctr Mat, Evry, France. NASA, CWRU, Glenn Res Ctr, Cleveland, OH USA. CNRS, CEA, Lab Pierre Sue, Saclay, France. RP Berger, MH (reprint author), Ecole Mine Paris, Ctr Mat, Evry, France. EM marie-helene.berger@ensmp.fr; ali.sayir@grc.nasa.gov; pascal.berger@cea.fr RI Berger, Marie-Helene/B-9785-2013 NR 13 TC 2 Z9 2 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0360-3199 J9 INT J HYDROGEN ENERG JI Int. J. Hydrog. Energy PD JUL PY 2006 VL 31 IS 8 BP 1103 EP 1111 DI 10.1016/j.ijhydene.2005.11.007 PG 9 WC Chemistry, Physical; Electrochemistry; Energy & Fuels SC Chemistry; Electrochemistry; Energy & Fuels GA 047VC UT WOS:000237905800012 ER PT J AU Williams, D Gorham, P Guillian, E Milincic, R Miocinovic, P Saltzberg, D Williams, D Field, RC Iverson, R Odian, A Walz, D Resch, G Schoessow, P AF Williams, D. Gorham, P. Guillian, E. Milincic, R. Miocinovic, P. Saltzberg, D. Williams, D. Field, R. C. Iverson, R. Odian, A. Walz, D. Resch, G. Schoessow, P. TI Radio signals from photon beams in sand and salt SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT International Workshop on Acoustic and Radio EeV Neutrino Detectioon Activities CY MAY 17-19, 2005 CL Zeuthen, GERMANY ID NEUTRINO DETECTION; EMISSION; SHOWERS; CHARGE; PULSES AB In this paper I describe the setup and results of two beamtests which demonstrated the existence and properties of the Askar'yan effect in sand and salt. We observed coherence, 100% linear polarization, and field strength in agreement with simulations. We also demonstrated the possibility of tracking the shower direction with polarization information. C1 Penn State Univ, University Pk, PA 16802 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Jet Prop Lab, Pasadena, CA USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. RP Williams, D (reprint author), Penn State Univ, University Pk, PA 16802 USA. NR 19 TC 2 Z9 2 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUL PY 2006 VL 21 SU 1 BP 35 EP 39 DI 10.1142/S0217751X06033325 PG 5 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 076WG UT WOS:000239988200007 ER PT J AU Gatson, JW Benz, BF Chandrasekaran, C Satomi, M Venkateswaran, K Hart, ME AF Gatson, Joshua W. Benz, Bruce F. Chandrasekaran, Chitra Satomi, Masataka Venkateswaran, Kasthuri Hart, Mark E. TI Bacillus tequilensis sp nov., isolated from a 2000-year-old Mexican shaft-tomb, is closely related to Bacillus subtilis SO INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY LA English DT Article ID DEPENDENT SUPEROXIDE-DISMUTASE; 16S RIBOSOMAL-RNA; EMENDED DESCRIPTIONS; GENUS PAENIBACILLUS; SOUTHERN SPAIN; SPECIES-LEVEL; IDENTIFICATION; STRAINS; CEREUS; ANTHRACIS AB A Gram-positive, spore-forming bacillus was isolated from a sample taken from an approximately 2000-year-old shaft-tomb located in the Mexican state of Jalisco, near the city of Tequila. Tentative identification using conventional biochemical analysis consistently identified the isolate as Bacillus subtilis. DNA isolated from the tomb isolate, strain 10b(T), and closely related species was used to amplify a Bacillus-specific portion of the highly conserved 16S rRNA gene and an internal region of the superoxide dismutase gene (sodA(int)). Trees derived from maximum-likelihood methods applied to the sodAint sequences yielded non-zero branch lengths between strain 10b(T) and its closest relative, whereas a comparison of a Bacillus-specific 546 bp amplicon of the 16S rRNA gene demonstrated 99% similarity with B. subtilis. Although the 16S rRNA gene sequences of strain 19b T and B. subtilis were 99 % similar, PFGE of Notl-digested DNA of strain 10b(T) revealed a restriction profile that was considerably different from those of B. subtilis and other closely related species. Whereas qualitative differences in whole-cell fatty acids were not observed, significant quantitative differences were found to exist between strain 1 Ob T and each of the other closely related Bacillus species examined. In addition, DNA-DNA hybridization studies demonstrated that strain 10b(T) had a relatedness value of less than 70% with B. subtilis and other closely related species. Evidence from the sodA(int) sequences, whole-cell fatty acid profiles and PFGE analysis, together with results from DNA-DNA hybridization studies, justify the classification of strain 1 Ob T as representing a distinct species, for which the name Bacillus tequilensis sp. nov. is proposed. The type strain is 10b(T) (=ATCC BAA-819(T) = NCTC 13306(T)). C1 Natl Ctr Toxicol Res, Div Microbiol, Jefferson, AR 72079 USA. CALTECH, Jet Prop Lab, Biotechnol & Planetary Protect Grp, Pasadena, CA 91109 USA. Natl Res Inst Fisheries, Div Food Proc, Yokohama, Kanagawa 2368648, Japan. Texas Wesleyan Univ, Dept Biol, Ft Worth, TX 76105 USA. Univ N Texas, Hlth Sci Ctr, Dept Mol Biol & Immunol, Ft Worth, TX 76107 USA. RP Hart, ME (reprint author), Natl Ctr Toxicol Res, Div Microbiol, HFT-250,3900 NCTR Rd, Jefferson, AR 72079 USA. EM mark.hart@fda.hhs.gov RI Hart, Mark/B-8976-2013 NR 37 TC 27 Z9 39 U1 0 U2 15 PU SOC GENERAL MICROBIOLOGY PI READING PA MARLBOROUGH HOUSE, BASINGSTOKE RD, SPENCERS WOODS, READING RG7 1AG, BERKS, ENGLAND SN 1466-5026 J9 INT J SYST EVOL MICR JI Int. J. Syst. Evol. Microbiol. PD JUL PY 2006 VL 56 BP 1475 EP 1484 DI 10.1099/ijs.0.63946-0 PN 7 PG 10 WC Microbiology SC Microbiology GA 068IF UT WOS:000239366200002 PM 16825615 ER PT J AU Osman, S Satomi, M Venkateswaran, K AF Osman, Shariff Satomi, Masataka Venkateswaran, Kasthuri TI Paenibacillus pasadenensis sp nov and Paenibacillus barengoltzii sp nov., isolated from a spacecraft assembly facility SO INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY LA English DT Article ID MARS ODYSSEY SPACECRAFT AB Two novel spore-forming, Gram-positive, mesophilic, heterotrophic bacteria representing two novel species were isolated from the Jet Propulsion Laboratory Spacecraft Assembly Facility (JPL-SAF) at Pasadena, CA, USA. The incidence of similar strains was examined by screening the growing collection of isolates (similar to 400 strains) obtained from the JPL-SAF using species-specific PCR primer sets designed from the 16S rRNA gene sequences of strains SAFN-016(T) and SAFN-007. Phylogenetic analysis of 16S rRNA gene sequences placed these novel isolates within the genus Paenibacillus. Two strains, SAFN-016(T) and SAFN-125, shared 98% 16S rRNA gene sequence similarity with Paenibacillus timonensis and 97% similarity with Paenibacillus macerans. Strain SAFN-007(T) showed 95(.)2% 16S rRNA gene sequence similarity with Paenibacillus kobensis, its nearest phylogenetic neighbour. The results of DNA-DNA hybridization, physiological tests and biochemical analysis allowed genotypic and phenotypic differentiation of the isolates from currently recognized Paenibacillus species. Strain SAFN-007 T and strains SAFN-016(T) and SAFN-125 are representatives of two separate novel species, for which the names Paenibacillus pasadenensis sp. nov. (type strain SAFN-007(T) = ATCC BAA-1211(T) = NBRC 101214(T)) and Paenibacillus barengoltzii sp. nov. (type strain SAFN-016(T) = ATCC BAA-1209(T) = NBRC 101215(T)) are proposed. C1 CALTECH, Jet Prop Lab, Biotechnol & Planetary Protect Grp, Pasadena, CA 91109 USA. Natl Res Inst Fisheries Sci, Fisheries Res Agcy, Yokohama, Kanagawa 2368648, Japan. RP Osman, S (reprint author), CALTECH, Jet Prop Lab, Biotechnol & Planetary Protect Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM sosman@jpl.nasa.gov NR 16 TC 29 Z9 30 U1 0 U2 14 PU SOC GENERAL MICROBIOLOGY PI READING PA MARLBOROUGH HOUSE, BASINGSTOKE RD, SPENCERS WOODS, READING RG7 1AG, BERKS, ENGLAND SN 1466-5026 J9 INT J SYST EVOL MICR JI Int. J. Syst. Evol. Microbiol. PD JUL PY 2006 VL 56 BP 1509 EP 1514 DI 10.1099/ijs.0.64085-0 PN 7 PG 6 WC Microbiology SC Microbiology GA 068IF UT WOS:000239366200008 PM 16825621 ER PT J AU Subramanian, CS Amer, T UpChurch, BT Alderfer, DW Burkett, C Sealey, B AF Subramanian, CS Amer, T UpChurch, BT Alderfer, DW Burkett, C Sealey, B TI New device and method for measuring thermal conductivity of thin-films SO ISA TRANSACTIONS LA English DT Article DE thermal conductivity meter; thin-film; transition; temperature sensitive paint AB Thermal sensitive paints (TSPs) are used for global nonintrusive detection of boundary layer transition in flow over the surface of wind tunnel research models. Since the transition is a transient process, the TSP should have a fast response characteristic. A low paint thermal conductivity is required for fast response. A thin-film thermal conductivity meter (TFTCM) was designed and built to measure thermal conductivity of the TSPs, which are typically between 50 and 150 mu m thick. In this paper, the design and operating features of the TFTCM are described. Measurement of the thermal conductivity with this TFTCM of three standard thin-film low conductivity specimens. Kapton, Teflon, and Borofloat glass, showed good agreement with the manufacturer quoted values. thus validating the instrument and the procedure. Consistently repeatable values for thermal conductivity (k=0.41 +/- 0.02 W/m K) were also obtained for the TSP specimen (TSB-B, 75 mu m) tested. (c) 2006 ISA-The Instrumentation, Systems, and Automation Society. C1 Florida Inst Technol, Melbourne, FL 32901 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Subramanian, CS (reprint author), Florida Inst Technol, Melbourne, FL 32901 USA. EM subraman@fit.edu; tahani.r.amer@nasa.gov OI Subramanian, Chelakara S./0000-0003-4149-2972 NR 12 TC 2 Z9 2 U1 1 U2 5 PU I S A-THE INSTRUMENTATION SYSTEMS AUTOMATION SOC PI RES TRIANGLE PK PA 67 ALEXANDER DR, PO BOX 12277, RES TRIANGLE PK, NC 27709 USA SN 0019-0578 J9 ISA T JI ISA Trans. PD JUL PY 2006 VL 45 IS 3 BP 313 EP 318 DI 10.1016/S0019-0578(07)60214-6 PG 6 WC Automation & Control Systems; Engineering, Multidisciplinary; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA 058XP UT WOS:000238698200001 PM 16856629 ER PT J AU Zampino, EJ AF Zampino, Edward J. TI Warp-drive metrics and the Yilmaz Theory SO JBIS-JOURNAL OF THE BRITISH INTERPLANETARY SOCIETY LA English DT Article DE warp drive; propulsion; spacetime; and general relativity ID GENERAL-RELATIVITY; ENERGY COMPONENTS; GRAVITATION FIELD; TRAVEL AB Concepts for faster-than-light warp drives and wormholes have been conceived within the framework of Einstein's general relativity. Variations of general relativity are explored as theorists seek ways to resolve the mismatch between general relativity and quantum mechanics and to find solutions to the dark matter and dark energy problems discovered through cosmology. One such variation, the Yilmaz Theory of Gravitation, adds a stress-energy tensor for gravitation to the right-hand side of the Einstein field equations, the side describing the source of spacetime curvature. Since black hole singularities and event horizons do not exist in the Yilmaz spacetime geometry, this may have the consequence of rendering warp drives and wormholes impossible. An analytical approach is suggested to investigate this question and to raise this issue so that other researchers pursuing breakthrough propulsion can take this unknown into account. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Zampino, EJ (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM Edward.J.Zampino@grc.nasa.gov NR 24 TC 2 Z9 2 U1 0 U2 1 PU BRITISH INTERPLANETARY SOC PI LONDON PA 27-29 S LAMBETH RD, LONDON SW8 1SZ, ENGLAND SN 0007-084X J9 JBIS-J BRIT INTERPLA JI JBIS-J. Br. Interplanet. Soc. PD JUL PY 2006 VL 59 IS 7 BP 226 EP 229 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Engineering; Astronomy & Astrophysics; Geology GA 049DG UT WOS:000237995300001 ER PT J AU Perko, HA Nelson, JD Green, JR AF Perko, HA Nelson, JD Green, JR TI Mars soil mechanical properties and suitability of mars soil simulants SO JOURNAL OF AEROSPACE ENGINEERING LA English DT Article AB Determination of Mars soil mechanical properties will improve future lander mission success and provide narrower constraints for geomorphological modeling. A soil mechanics investigation was conducted wherein soil mechanical properties were determined by computer reconstruction of mass wasting features observed in photographs of Mars Exploration Rover landing sites and analysis of natural slope stability. Mars soil mechanical properties were compared with thermal inertia measurements and a correlation is presented. Tests with rovers and equipment for Mars surface exploration and various past laboratory experiments have incorporated a number of different Mars soil simulants. Standard laboratory measurements were conducted to characterize the shear strength. grain size distribution, and densities of various Mars soil simulants. From these measurements. the ability of a given simulant to appropriately represent the mechanical properties of in situ Mars soils was judged. Specific simulants are recommended for certain regions of Mars. C1 CTL Thompson Inc & Secure Engn Co, Ft Collins, CO USA. Colorado State Univ, Ft Collins, CO 80523 USA. NASA, Jet Propuls Lab, Extraterr Mat Simulat Lab, Pasadena, CA USA. RP Perko, HA (reprint author), CTL Thompson Inc & Secure Engn Co, 211 W Magnolia, Ft Collins, CO USA. EM hperko@secureengineer.com; john@engr.colostate.edu; jacklyn.r.green@jpl.nasa.gov NR 4 TC 15 Z9 16 U1 1 U2 7 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 JUL PY 2006 VL 19 IS 3 BP 169 EP 176 DI 10.1061/(ASCE)0893-1321(2006)19:3(169) PG 8 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA 055DV UT WOS:000238431100003 ER PT J AU Chabalko, CC Ge, ZF Hajj, MR Silva, WA AF Chabalko, Christopher C. Ge, Zhongfu Hajj, Muhammad R. Silva, Walter A. TI Analysis tools for the detection of intermittent nonlinear aeroelastic phenomena SO JOURNAL OF AIRCRAFT 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 WAVE INTERACTIONS; TURBULENCE AB The nonlinear coupling between the aerodynamic load and structural motions in the experiments conducted in the Langley Transonic Dynamics Tunnel at NASA Langley Research Center on a flexible semispan model (FSM) of a high-speed civil transport wing configuration is examined. The results show that, right before "hard" flutter took place, the aerodynamic load and the structural motion of the FSM were intermittently and quadratically coupled. Particularly, the shock motion, which can be caused by local and intermittent How separation, is nonlinearly related to the structural motion in such a manner that one full cycle of the shock motion is related to two cycles of the acceleration of the wing tip. Because of the required averaging in implementing them, Fourier-based higher-order spectral moments could not characterize this coupling. On the other hand, the wavelet-based cross bicoherence is established as a tool that is capable of detecting intermittent or transient nonlinear aeroelastic phenomena as would be encountered in model studies or flight tests. C1 Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. NASA Langley Res Ctr, Hampton, VA 23681 USA. RP Chabalko, CC (reprint author), Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. RI Hajj, Muhammad/A-1176-2010 NR 13 TC 4 Z9 4 U1 0 U2 0 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 JUL-AUG PY 2006 VL 43 IS 4 BP 1082 EP 1088 DI 10.2514/1.17639 PG 7 WC Engineering, Aerospace SC Engineering GA 070SQ UT WOS:000239544600025 ER PT J AU Abdol-Hamid, KS Elmiligui, A Hunter, CA AF Abdol-Hamid, K. S. Elmiligui, Alaa Hunter, Craig A. TI Numerical investigation of flow in an overexpanded nozzle with porous surfaces SO JOURNAL OF AIRCRAFT 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 AB A new porous condition has been implemented in the PAB3D solver to simulate flow over porous surfaces. The newly added boundary condition is utilized to compute the flow field of a nonaxisymmetric, convergent-divergent nozzle incorporating porous cavities for shock-boundary layer interaction control. The nozzle has an expansion ratio (exit area/throat area) of 1.797 and a design nozzle pressure ratio (NPR) of 8.78. The flow fields for a baseline nozzle (no porosity) and for a nozzle with porous surfaces (10% porosity ratio) are computed for NPR varying from 2.01 to 9.54. Computational model results indicate that the overexpanded nozzle flow is dominated by shock-induced boundary-layer separation. Porous configurations are capable of controlling off-design separation in the nozzle by encouraging stable separation of the exhaust flow. Computational simulation results, wall centerline pressure, Mach contours, and thrust efficiency ratio are presented and discussed. Computed results are in excellent agreement with experimental data. C1 NASA Langley Res Ctr, Configurat Aerodynam Branch, Hampton, VA 23681 USA. Analyt Serv & Mat Inc, Hampton, VA 23666 USA. RP Abdol-Hamid, KS (reprint author), NASA Langley Res Ctr, Configurat Aerodynam Branch, MS 499, Hampton, VA 23681 USA. NR 17 TC 0 Z9 0 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 JUL-AUG PY 2006 VL 43 IS 4 BP 1217 EP 1225 DI 10.2514/1.18835 PG 9 WC Engineering, Aerospace SC Engineering GA 070SQ UT WOS:000239544600041 ER PT J AU Broeren, AP Bragg, MB Addy, HE AF Broeren, Andy P. Bragg, Michael B. Addy, Harold E., Jr. TI Flowfield measurements about an airfoil with leading-edge ice shapes SO JOURNAL OF AIRCRAFT 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 SHEAR-LAYER; AERODYNAMICS; SEPARATION AB Flowfield measurements were carried out on the upper surface of a GLC-305 airfoil configured with glaze and rime ice-shape simulations. The mean and root-mean-square fluctuation of the streamwise velocity were measured using a split-hot-film probe at several chordwise locations. These data were taken at three different angles of attack preceding stall for each iced-airfoil configuration at Reynolds numbers of 3.5 x 10(6) and 6.0 x 10(6) with Mach numbers of 0.12 and 0.21. The velocity measurements confirmed the presence of a large separation bubble downstream of the ice shapes. The separation bubbles for the glaze ice configuration were much larger than those for the rime ice case, resulting from the differences in the ice horn geometry. Other than the differences in size, the integral boundary-layer characteristics were very similar. Changes in Reynolds number did not significantly affect the separation bubble characteristics. However, a larger Mach number did result in a slightly larger separation bubble for the glaze ice case at alpha = 6 deg. The root-mean-square velocity distributions had peak values in the separated shear layer, downstream of transition, that compared well with previous work. C1 Univ Illinois, Dept Aerosp Engn, Urbana, IL 61801 USA. NASA John H Glenn Res Ctr Lewis Field, Icing Branch, Cleveland, OH 44135 USA. RP Broeren, AP (reprint author), Univ Illinois, Dept Aerosp Engn, 306 Talbot Lab,104 S Wright St, Urbana, IL 61801 USA. NR 27 TC 9 Z9 10 U1 1 U2 4 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 JUL-AUG PY 2006 VL 43 IS 4 BP 1226 EP 1234 DI 10.2514/1.19021 PG 9 WC Engineering, Aerospace SC Engineering GA 070SQ UT WOS:000239544600042 ER PT J AU Biggerstaff, MI Seo, EK Hristova-Veleva, SM Kim, KY AF Biggerstaff, Michael I. Seo, Eun-Kyoung Hristova-Veleva, Svetla M. Kim, Kwang-Yul TI Impact of cloud model microphysics on passive microwave retrievals of cloud properties. Part I: Model comparison using EOF analyses SO JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY LA English DT Article ID 1985 SQUALL LINE; PHYSICAL PRECIPITATION RETRIEVAL; MESOSCALE CONVECTIVE SYSTEMS; MEASURING MISSION TRMM; SATELLITE MEASUREMENTS; RADIATION MODEL; RAIN RATES; RADAR; PARAMETERIZATION; RADIANCES AB The impact of model microphysics on the relationships among hydrometeor profiles, latent heating, and derived satellite microwave brightness temperatures T-B have been examined using a nonhydrostatic, adaptive-grid cloud model to simulate a mesoscale convective system over water. Two microphysical schemes ( each employing three-ice bulk parameterizations) were tested for two different assumptions in the number of ice crystals assumed to be activated at 0 degrees C to produce simulations with differing amounts of supercooled cloud water. The model output was examined using empirical orthogonal function (EOF) analysis, which provided a quantitative framework in which to compare the simulations. Differences in the structure of the vertical anomaly patterns were related to physical processes and attributed to different approaches in cloud microphysical parameterizations in the two schemes. Correlations between the first EOF coefficients of cloud properties and T-B at frequencies associated with the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) showed additional differences between the two parameterization schemes that affected the relationship between hydrometeors and T-B. Classified in terms of T-B, the microphysical schemes produced significantly different mean vertical profiles of cloud water, cloud ice, snow, vertical velocity, and latent heating. The impact of supercooled cloud water on the 85-GHz T-B led to a 15% variation in mean convective rain mass at the surface. The variability in mean profiles produced by the four simulations indicates that the retrievals of cloud properties, especially latent heating, based on TMI frequencies are dependent on the particular microphysical parameterizations used to construct the retrieval database. C1 Univ Oklahoma, Sch Meteorol, Norman, OK 73019 USA. Jet Propuls Lab, Pasadena, CA USA. Florida State Univ, Tallahassee, FL 32306 USA. RP Biggerstaff, MI (reprint author), Univ Oklahoma, Sch Meteorol, 100 E Boyd St,SEC Rm 1310, Norman, OK 73019 USA. EM drdoppler@ou.edu OI Biggerstaff, Michael/0000-0002-6690-784X NR 68 TC 15 Z9 15 U1 0 U2 6 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 JUL PY 2006 VL 45 IS 7 BP 930 EP 954 DI 10.1175/JAM2372.1 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 065SM UT WOS:000239179600003 ER PT J AU Merceret, FJ AF Merceret, Francis J. TI Rapid temporal changes of boundary layer winds SO JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY LA English DT Article AB The statistical distribution of the magnitude of the vector wind change over 0.25-, 0.5-, 1-, and 2-h periods based on central Florida data from November 1999 through August 2001 is presented. The distributions of the 2-h u and v wind-component changes are also presented for comparison. The wind changes at altitudes from 500 to 3000 m were measured using the Eastern Range network of five 915-MHz Doppler radar wind profilers. Quality-controlled profiles were produced every 15 min for up to 60 gates, each representing 101 m in altitude over the range from 130 to 6089 m. Five levels, each constituting three consecutive gates, were selected for analysis because of their significance to aerodynamic loads during the space-shuttle-ascent roll maneuver. The distribution of the magnitude of the vector wind change is found to be lognormal, consistent with earlier work in the midtroposphere. The parameters of the distribution vary with time lag, season, and altitude. The component wind changes are symmetrically distributed, with near-zero means, but the kurtosis coefficient is larger than that of a Gaussian distribution. C1 NASA, YAD, Kennedy Space Ctr, FL 32899 USA. RP Merceret, FJ (reprint author), NASA, YAD, Kennedy Space Ctr, FL 32899 USA. EM francis.j.merceret@nasa.gov NR 5 TC 0 Z9 0 U1 0 U2 1 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 JUL PY 2006 VL 45 IS 7 BP 1016 EP 1020 DI 10.1175/JAM2377.1 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 065SM UT WOS:000239179600009 ER PT J AU Wonsick, MM Pinker, RT Meng, W Nguyen, L AF Wonsick, Margaret M. Pinker, Rachel T. Meng, Wen Nguyen, Louis TI Evaluation of surface shortwave flux estimates from GOES: Sensitivity to sensor calibration SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID CLOUD-COVER; SYSTEM; ASSIMILATION; IMAGERS; MODIS AB Parameters derived from satellite observations depend on the quality of the calibration method applied to the raw satellite radiance measurements. This study investigates the sensitivity of absolute reflectance, derived cloud cover, and estimated surface shortwave (SW) downward fluxes to two different calibration methods for the visible sensor aboard the eighth Geostationary Operational Environmental Satellite (GOES-8). The first method was developed at NOAA's National Environmental Satellite, Data, and Information Service (NESDIS), and the second at the NASA Langley Research Center. Differences in visible reflectance ranged from -0.5% to 3%. The average difference in monthly mean cloud amount was similar to 3%, and the average difference in monthly mean shortwave downward flux was 5 W m(-2). Differences in bias and rms of the SW fluxes when evaluated against ground station measurements were less than 3 W m(-2). Neither calibration method was shown to consistently outperform the other. This evaluation yields an estimate of the errors in fluxes that can be attributed to calibration. C1 Univ Maryland, Dept Atmospher & Ocean Sci, College Pk, MD 20742 USA. NASA, Langley Res Ctr, Climate Sci Branch, Hampton, VA USA. RP Wonsick, MM (reprint author), Univ Maryland, Dept Atmospher & Ocean Sci, Comp & Space Sci Bldg, College Pk, MD 20742 USA. EM mwonsick@atmos.umd.edu RI Pinker, Rachel/F-6565-2010 NR 22 TC 3 Z9 3 U1 0 U2 0 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 JUL PY 2006 VL 23 IS 7 BP 927 EP 935 DI 10.1175/JTECH1894.1 PG 9 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 069MH UT WOS:000239450600005 ER PT J AU Bliziotes, M Sibonga, JD Turner, RT Orwoll, E AF Bliziotes, M Sibonga, JD Turner, RT Orwoll, E TI Periosteal remodeling at the femoral neck in nonhuman primates SO JOURNAL OF BONE AND MINERAL RESEARCH LA English DT Article; Proceedings Paper CT 24th Annual Meeting of the American-Society-for-Bone-and-Mineral-Research CY SEP 20-24, 2002 CL SAN ANTONIO, TX SP Amer Soc Bone & Mineral Res DE primate; osteoblasts; modeling and remodeling; bone histomorphometry; bone mineralization; periosteum ID INTRACAPSULAR HIP FRACTURE; BONE HISTOMORPHOMETRY; CORTICAL BONE; PROXIMAL FEMUR; OSTEOPOROSIS; SIZE; WOMEN; FRAGILITY; POROSITY; DENSITY AB Introduction: Bone size is an important determinant of bone strength, and cellular events at the periosteal surface could alter bone dimensions. We characterized periosteal cellular activity with dynamic histomorphometric studies of nonhuman primate femoral neck and shaft. Materials and Methods: Femur specimens from 16 intact adult male and female nonhuman primates (Rhesus [Macaca mulatta, n = 9] and Japanese Macaque [Macaca fuscata, n = 7]) were analyzed. Animals were double-labeled with tetracycline, and necropsy was performed 2-7 days after the last dose. We characterized periosteal resorptive activity in an additional group of five intact and four castrate female animals. Multiple group comparisons in intact animals were performed by one-way ANOVA followed by a Fisher PLSD posthoc test. In gonadectomized animals, Fisher's exact test was used for dichotomous and Mann-Whitney U-test for continuous variables. Results: Bone turnover in the periosteum of the femoral neck in intact animals was more rapid than at the femoral shaft but slower than in femoral neck cancellous bone. Similarly, in these intact animals, the eroded surface of cortical bone at the femoral neck periosteal surface was significantly greater than in the cancellous bone compartment (p < 0.0001) or on the femoral shaft (p < 0.0001). Gonadectomized female animals showed an increase in osteoclast number on the periosteal surface compared with intact controls (p < 0.01). Conclusions: We documented intramembranous periosteal bone turnover in the femoral neck by histomorphometric analyses. The tissue level bone formation rate was sufficient to add substantively to femoral neck size over time. Periosteal osteoclastic activity was not the result of the emergence of intracortical tunneling at the bone surface. Sex steroid deficiency produced an increase in osteoclast numbers at the periosteal surface. This is the first systematic documentation of periosteal turnover at the femoral neck. C1 Oregon Hlth & Sci Univ, Portland, OR 97201 USA. Portland VA Med Ctr, Portland, OR 97201 USA. Univ Space Res Assoc, Johnson Space Ctr, Div Space Life Sci, Houston, TX USA. Mayo Clin, Rochester, MN USA. Oregon State Univ, Dept Nutr & Exercise Sci, Corvallis, OR 97331 USA. RP Bliziotes, M (reprint author), Oregon Hlth & Sci Univ, Portland, OR 97201 USA. EM bliziote@ohsu.edu OI Orwoll, Eric/0000-0002-8520-7355 FU NIAMS NIH HHS [AR48833] NR 32 TC 20 Z9 20 U1 0 U2 1 PU AMER SOC BONE & MINERAL RES PI WASHINGTON PA 2025 M ST, N W, STE 800, WASHINGTON, DC 20036-3309 USA SN 0884-0431 J9 J BONE MINER RES JI J. Bone Miner. Res. PD JUL PY 2006 VL 21 IS 7 BP 1060 EP 1067 DI 10.1359/JBMR.060414 PG 8 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 057MW UT WOS:000238600900014 PM 16813526 ER PT J AU Petersen, WA Fu, R Chen, MX Blakeslee, R AF Petersen, Walter A. Fu, Rong Chen, Mingxuan Blakeslee, Richard TI Intraseasonal forcing of convection and lightning activity in the southern Amazon as a function of cross-equatorial flow SO JOURNAL OF CLIMATE LA English DT Article ID TROPOSPHERIC WATER-VAPOR; TRMM PRECIPITATION RADAR; VERTICAL VELOCITY; DIURNAL CYCLE; SQUALL LINES; CLOUD; VARIABILITY; AMERICA; WET; REFLECTIVITY AB This study focuses on modulation of lightning and convective vertical structure in the southern Amazon as a function of the South American monsoon V index ( VI). Four wet seasons ( December - March 1998 2001) of Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor ( LIS) and Precipitation Radar ( PR) data are examined together with two wet seasons ( 2000 - 01) of ground-based Brazilian Lightning Detection Network (BLDN) data. These observations are composited by VI phase ( northerly or southerly) for a region of the southern Amazon and discussed relative to VI-regime environmental characteristics such as thermodynamic instability and wind shear. Relative comparisons of VI-regime convective properties reveal 1) slightly larger (20% - 25%) PR pixel-mean rainfall during periods of northerly VI due to increased stratiform precipitation, 2) a factor of 2 or more increase in lightning flash density and the lightning diurnal cycle amplitude during periods of southerly VI, 3) a factor of 1.5 - 2 increase in the conditional probability of any PR radar reflectivity pixel exceeding 30 dBZ above the - 10 degrees C level during periods of southerly VI, and 4) an associated factor of 2 or more increase in southerly VI pixel-mean ice water path, with the ice water path being highly correlated to trends in lightning activity. During periods of southerly VI, convection occurs in an environment of increased thermodynamic instability, weak southeasterly low-level, and deep upper-tropospheric easterly wind shear. During periods of northerly VI, low-level westerly shear opposes stronger deep tropospheric easterly shear in a relatively moist environment of weaker thermodynamic instability, consistent with the occurrence of more widespread stratiform precipitation. The composite results of this study point to 1) regime differences in convective forcing that alter the prevalence of ice processes and, by inference, the vertical profile of latent heating and 2) the utility of lightning observations in delineating convective regime changes. C1 Univ Alabama, ESSC, NSSTC, Huntsville, AL 35899 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Petersen, WA (reprint author), Univ Alabama, ESSC, NSSTC, Huntsville, AL 35899 USA. EM walt.petersen@msfc.nasa.gov RI Fu, Rong/B-4922-2011 NR 52 TC 14 Z9 16 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 JUL PY 2006 VL 19 IS 13 BP 3180 EP 3196 DI 10.1175/JCLI3788.1 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 063NO UT WOS:000239026300009 ER PT J AU Tang, YM Kleeman, R Miller, S AF Tang, Youmin Kleeman, Richard Miller, Sonya TI ENSO predictability of a fully coupled GCM model using singular vector analysis SO JOURNAL OF CLIMATE LA English DT Article ID OCEAN-ATMOSPHERE MODEL; STOCHASTIC DYNAMICAL MODEL; NINO SOUTHERN-OSCILLATION; OPTIMAL-GROWTH; TROPICAL PACIFIC; EL-NINO; INITIAL CONDITIONS; ERROR GROWTH; PART II; PREDICTION AB Using a recently developed method of computing climatically relevant singular vectors (SVs), the error growth properties of ENSO in a fully coupled global climate model are investigated. In particular, the authors examine in detail how singular vectors are influenced by the phase of ENSO cycle-the physical variable under consideration as well as the error norm deployed. Previous work using SVs for studying ENSO predictability has been limited to intermediate or hybrid coupled models. The results show that the singular vectors share many of the properties already seen in simpler models. Thus, for example, the singular vector spectrum is dominated by one fastest growing member, regardless of the phase of ENSO cycle and the variable of perturbation or the error norm; in addition the growth rates of the singular vectors are very sensitive to the phase of the ENSO cycle, the variable of perturbation, and the error norm. This particular CGCM also displays some differences from simpler models; thus subsurface temperature optimal patterns are strongly sensitive to the phase of ENSO cycle, and at times an east-west dipole in the eastern tropical Pacific basin is seen. This optimal pattern also appears for SST when the error norm is defined using Nino-4. Simpler models consistently display a single-sign equatorial signature in the subsurface corresponding perhaps to the Wyrtki buildup of heat content before a warm event. Some deficiencies in the CGCM and their possible influences on SV growth are also discussed. C1 Univ No British Columbia, Prince George, BC V2N 4Z9, Canada. NYU, Courant Inst Math Sci, New York, NY USA. Sci Applicat Int Corp, Greenbelt, MD USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tang, YM (reprint author), Univ No British Columbia, 3333 Univ Way, Prince George, BC V2N 4Z9, Canada. EM ytang@unbc.ca NR 41 TC 21 Z9 21 U1 1 U2 2 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 JUL PY 2006 VL 19 IS 14 BP 3361 EP 3377 DI 10.1175/JCLI3771.1 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 063NP UT WOS:000239026400003 ER PT J AU Romanou, A Rossow, WB Chou, SH AF Romanou, Anastasia Rossow, William B. Chou, Shu-Hsien TI Decorrelation scales of high-resolution turbulent fluxes at the ocean surface and a method to fill in gaps in satellite data products SO JOURNAL OF CLIMATE LA English DT Article ID LATENT-HEAT FLUXES; 1997-98 EL-NINO; GLOBAL OCEANS; PACIFIC; TEMPERATURE; PROJECT; VARIABILITY; ATMOSPHERE; LAYER AB In the first part of the paper, a high space-time resolution (1 degrees latitude/longitude and daily) dataset of the turbulent fluxes at the ocean surface is used to estimate and study the seasonal to annual near-global maps of the decorrelation scales of the latent and sensible heat fluxes. The decorrelation scales describe the temporal and spatial patterns that dominate the flux fields (within a bandpass window) and hence reveal the dominant variability in the air-sea interaction. Regional comparison to the decorrelation scales of the flux-related variables such as the wind stress, the humidity difference, and the SST identifies the main mechanism responsible for the variability in each flux field. In the second part of the paper, the decorrelation scales are used to develop a method for filling missing values in the dataset that result from the incomplete satellite coverage. Weight coefficients in a linear regression function are determined from the spatial and temporal decorrelations and are functions of zonal and meridional distance and time. Therefore they account for all spatial and temporal patterns on scales greater than 1 day and 1 latitude/longitude and less than 1 yr and the ocean basin scale. The method is evaluated by simulating the missing-value distribution of the Goddard Satellite-Based Surface Turbulent Fluxes, version 2 (GSSTF2) dataset in the NCEP SST, the International Satellite Climatology Project (ISCCP)-FD (fluxes calculated using D1 series) surface radiation, and the Global Precipitation Climatology Project (GPCP) datasets and by comparing the filled datasets to the original ones. Main advantages of the method are that the decorrelation scales are unrestricted functions of space and time; only information internal to the flux field is used in the interpolation scheme, and the computation cost of the method is low enough to facilitate its use in similar large datasets. C1 Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10025 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Natl Taiwan Univ, Dept Atmospher Sci, Taipei 10764, Taiwan. RP Romanou, A (reprint author), Columbia Univ, Dept Appl Phys & Appl Math, 2880 Broadway, New York, NY 10025 USA. EM ar2235@columbia.edu RI Rossow, William/F-3138-2015 NR 31 TC 6 Z9 7 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 EI 1520-0442 J9 J CLIMATE JI J. Clim. PD JUL PY 2006 VL 19 IS 14 BP 3378 EP 3393 DI 10.1175/JCLI3773.1 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 063NP UT WOS:000239026400004 ER PT J AU Xie, SP Xu, HM Saji, NH Wang, YQ Liu, WT AF Xie, Shang-Ping Xu, Haiming Saji, N. H. Wang, Yuqing Liu, W. Timothy TI Role of narrow mountains in large-scale organization of Asian monsoon convection SO JOURNAL OF CLIMATE LA English DT Article ID SUMMER MONSOON; GHAT MOUNTAINS; PRECIPITATION; OCEAN; SIMULATION; MODEL; VARIABILITY; CIRCULATION; DYNAMICS; PACIFIC AB The Asian summer monsoon is organized into distinct convection centers, but the mechanism for this organization is not well understood. Analysis of new satellite observations reveals that narrow mountain ranges are an important organizing agent anchoring monsoon convection centers on the windward side. The Bay of Bengal convection, in particular, features the heaviest precipitation on its eastern coast because of orographic lifting as the southwest monsoon impinges on the coastal mountains of Myanmar ( also known as Burma). This is in contrast to the widely held view that this convection is centered over the open ocean as implied by coarse-resolution datasets, a view that would require an entirely different explanation for its formation. Narrow in width and modest in height (<= 1 km), these mountains are hardly mentioned in conceptual depictions of the large- scale monsoon and poorly represented in global climate models. The numerical simulations of this study show that orographic rainbands are not a local phenomenon but exert far-reaching effects on the continental-scale monsoon. The realization that these overlooked geographical features are an important element of the Asian monsoon has important implications for studying the monsoon in the past, present, and future. C1 Univ Hawaii Manoa, Int Pacific Res Ctr, SOEST, Honolulu, HI 96822 USA. Jet Prop Lab, Pasadena, CA USA. Univ Hawaii Manoa, Dept Meteorol, Honolulu, HI 96822 USA. Nanjing Univ Informat Sci & Technol, Dept Atmospher Sci, Nanjing, Peoples R China. RP Xie, SP (reprint author), Univ Hawaii Manoa, Int Pacific Res Ctr, SOEST, Honolulu, HI 96822 USA. EM xie@hawaii.edu RI Xie, Shang-Ping/C-1254-2009; Hameed, Saji/B-9188-2009 OI Xie, Shang-Ping/0000-0002-3676-1325; Hameed, Saji/0000-0002-6199-9853 NR 34 TC 133 Z9 139 U1 2 U2 19 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 JUL PY 2006 VL 19 IS 14 BP 3420 EP 3429 DI 10.1175/JCLI3777.1 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 063NP UT WOS:000239026400007 ER PT J AU Dick, J Knox, L Chu, M AF Dick, Jason Knox, Lloyd Chu, Mike TI Reduction of cosmological data for the detection of time-varying dark energy density SO JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS LA English DT Article DE CMBR experiments; dark energy theory; supernova type Ia; cosmological constant experiments ID MICROWAVE BACKGROUND MEASUREMENTS; PARAMETERS; SUPERNOVAE; CONSTANT; REDSHIFT; UNIVERSE; IMAGER; MATTER; SPACE; MAPS AB We present a method for reducing cosmological data to constraints on the amplitudes of modes of the dark energy density as a function of redshift. The modes are chosen so that (1) one of them has constant density and (2) the others are non-zero only if there is time-variation in the dark energy density and (3) the amplitude errors for the time-varying modes are uncorrelated with each other. We apply our method to various combinations of three-year WMAP data, baryon acoustic oscillation data, the 'Gold' supernova data set, and the Supernova Legacy Survey data set. We find no significant evidence for a time-varying dark energy density or for non-zero mean curvature. Although by some measure the limits on four of the time-varying mode amplitudes are quite tight, they are consistent with the expectation that the dark energy density does not vary on timescales shorter than a Hubble time. Since we do not expect detectable time variation in these modes, our results should be viewed as a systematic error test which the data have passed. We discuss a procedure to identify modes with maximal signal-to-noise ratio. C1 Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Dick, J (reprint author), Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. EM jadick@ucdavis.edu; lknox@ucdavis.edu; chu@milkyway.gsfc.nasa.gov NR 49 TC 25 Z9 26 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 1475-7516 J9 J COSMOL ASTROPART P JI J. Cosmol. Astropart. Phys. PD JUL PY 2006 IS 7 AR 001 DI 10.1088/1475-7516/2006/07/001 PG 24 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 069MI UT WOS:000239451000015 ER PT J AU Douglas, PK Batdorf, NJ Evans, RT Feiveson, AH Arenare, B Schlegel, TT AF Douglas, PK Batdorf, NJ Evans, RT Feiveson, AH Arenare, B Schlegel, TT TI Temporal and postural variation of 12-lead high-frequency QRS electrocardiographic signals in asymptomatic individuals SO JOURNAL OF ELECTROCARDIOLOGY LA English DT Article DE high-frequency QRS; signal-averaged ECG; posture; reduced amplitude zone; ischemia ID CORONARY-ARTERY-DISEASE; BODY-SURFACE ELECTROCARDIOGRAM; MYOCARDIAL-ISCHEMIA; AVERAGED ECG; OCCLUSION; STANDARD; POPULATION; POSITION; LEADS; DOGS AB Because changes in the 12-lead high-frequency QRS electrocardiogram (HF QRS ECG) more sensitively identify myocardial ischemia than do changes in the ST segments of the conventional ECG, it is important that changes in HF QRS signals that are merely physiological be distinguishable from those that are potentially pathological. We therefore studied the temporal variation of HF QRS measures such as root mean square (RMS) voltage and the presence vs absence of reduced amplitude zones (RAZs) in 107 asymptomatic individuals in the supine position during a brief period of ECG monitoring. In addition, to ascertain the effects of posture on the 12-lead HE QRS ECG, we collected additional seated data from 25 of these individuals and estimated the fifth and 95th percentile of the percent relative change between the supine and seated measurements. In all cases, variation of HE QRS parameters decreased as the number of beats in the signal average increased. For example, in the supine position, the 95th percentile of the percent relative change between consecutive within-lead measurements of RMS voltage for a 50-beat signal average was 12.3% but decreased to 11.7%, 11.2%, and 10.7% for 75, 100, and 150 beat signal averages, respectively (P < .01). After transition from the supine to the seated upright position, changes in some measures of HF QRS were statistically significant, with RMS voltage decreasing significantly in lead V-3 and with the number of RAZs lost in the 12-lead HF QRS ECG significantly exceeding the number of RAZs gained. We conclude that most measures of HE QRS ECG are sufficiently stable for routine continuous monitoring. (c) 2006 Elsevier Inc. All rights reserved. C1 Natl Space Biomed Res Inst, Houston, TX 77030 USA. NASA, Lyndon B Johnson Space Ctr, Human Adaptat & Countermeasures Off, Houston, TX 77058 USA. RP Schlegel, TT (reprint author), NASA, Johnston Space Ctr, Mail Code SK3, Houston, TX 77058 USA. EM todd.t.schlegel@nasa.gov NR 24 TC 6 Z9 6 U1 0 U2 2 PU CHURCHILL LIVINGSTONE INC MEDICAL PUBLISHERS PI PHILADELPHIA PA CURTIS CENTER, INDEPENDENCE SQUARE WEST, PHILADELPHIA, PA 19106-3399 USA SN 0022-0736 J9 J ELECTROCARDIOL JI J. Electrocardiol. PD JUL PY 2006 VL 39 IS 3 BP 259 EP 265 DI 10.1016/j.jelectrocard.2005.10.011 PG 7 WC Cardiac & Cardiovascular Systems SC Cardiovascular System & Cardiology GA 059FM UT WOS:000238718700002 PM 16777512 ER PT J AU Batdorf, BH Feiveson, AH Schlegel, TT AF Batdorf, BH Feiveson, AH Schlegel, TT TI The effect of signal averaging on the reproducibility and reliability of measures of T-wave morphology SO JOURNAL OF ELECTROCARDIOLOGY LA English DT Article DE median beat; principal component analysis; repolarization heterogeneity; signal averaging; singular value decomposition; T-wave residuum ID PRINCIPAL COMPONENT ANALYSIS; REPOLARIZATION; ELECTROCARDIOGRAPHY; PREDICTION AB Electrocardiographic repolarization abnormalities characterized by T-wave morphology parameters such as the principal component analysis ratio and the relative and the absolute T-wave residuum (TWRrel and TWRabs) are predictive of cardiovascular and/or all-cause mortality. However, when using a "10-second median beat" for analysis, the reported mean values for TWRrel vary widely and parameter reproducibility is somewhat suspect. In repeated electrocardiographic recordings conducted I month and I year apart on 15 and 27 healthy individuals, respectively, we studied the said T-wave morphology parameters in single complexes and in reduced noise signal averages containing 10 and 200 complexes. Considering all subjects, the mean (+/- SD) TWRrel was highest in a single complex (0.0345% +/- 0.0183%), intermediate in the 10-beat signal-averaged complexes (0.0125% +/- 0.0051%), and lowest in the 200-beat signal-averaged complexes (0.0078% +/- 0.0036%) (P < .0001), with the same trend also observed in the TWRabs but not in the principal component analysis ratio. Reproducibility as quantified by within-subject variance and reliability as quantified by the intraclass (intrasubject) correlation coefficient also improved as the number of T-wave complexes analyzed increased. We conclude that signal averages consisting of more than 10 complexes (or more than 10 seconds worth of complexes) are required to produce reproducible and reliable values for TWRrel and TWRabs. (c) 2006 Elsevier Inc. All rights reserved. C1 Natl Space Biomed Res Inst, Houston, TX 77030 USA. RP Schlegel, TT (reprint author), NASA, Johnson Space Ctr, Houston, TX 77058 USA. EM todd.t.schlegel@nasa.gov NR 19 TC 19 Z9 19 U1 0 U2 1 PU CHURCHILL LIVINGSTONE INC MEDICAL PUBLISHERS PI PHILADELPHIA PA CURTIS CENTER, INDEPENDENCE SQUARE WEST, PHILADELPHIA, PA 19106-3399 USA SN 0022-0736 J9 J ELECTROCARDIOL JI J. Electrocardiol. PD JUL PY 2006 VL 39 IS 3 BP 266 EP 270 DI 10.1016/j.jelectrocard.2005.11.004 PG 5 WC Cardiac & Cardiovascular Systems SC Cardiovascular System & Cardiology GA 059FM UT WOS:000238718700003 PM 16529767 ER PT J AU Gao, XJ Burton, D Turner, TL Brinson, LC AF Gao, Xiujie Burton, Deborah Turner, Travis L. Brinson, L. Catherine TI Finite element analysis of adaptive-stiffening and shape-control SMA hybrid composites SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT Workshop on Damping of Shape Memory Alloys, Composites, and Foams CY MAY 10-11, 2005 CL Georgia Tech Lorraine, Metz, FRANCE SP Natl Sci Fdn, Univ Paul Verlaine Metz, Georgia Inst Technol, Lab Phys Mecan Mat CNRS, Counseil Reg Lorraine HO Georgia Tech Lorraine DE shape memory alloys; nitinol; ABAQUS; finite element analysis; post-buckling control; shape control; deflection control; adaptive stiffening; morphing; constitutive modeling; user element ID MEMORY ALLOY WIRES; THERMOMECHANICAL RESPONSE; MICROMECHANICAL ANALYSIS; MATRIX COMPOSITE; TINI FIBERS; BEHAVIOR; ACTUATORS; SHELLS; PLATE; BEAMS AB Shape memory alloy (SMA) hybrid composites with adaptive-stiffening or morphing functions are simulated using finite element analysis. The composite structure is a laminated fiber-polymer composite beam with embedded SMA ribbons at various positions with respect to the neutral axis of the beam. Adaptive stiffening or morphing is activated via selective resistance heating of the SMA ribbons or uniform thermal loads on tire beam. The thermomechanical behavior of these composites it-as simulated in ABAQUS using user-defined SMA elements. The examples demonstrate the usefulness of the methods for the design and simulation of SMA hybrid composites. C1 Northwestern Univ, Dept Mech Engn, Evanston, IL 60208 USA. NASA, Struct Acoust Branch, Langley Res Ctr, Hampton, VA 23681 USA. Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. RP Gao, XJ (reprint author), GM Corp, Res & Dev, Warren, MI 48090 USA. EM cbrinson@northwestern.edu RI Brinson, L. Catherine/B-6678-2009; Burton, Deborah/E-3908-2010; Brinson, L Catherine/B-1315-2013 OI Brinson, L Catherine/0000-0003-2551-1563 NR 44 TC 7 Z9 8 U1 1 U2 7 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD JUL PY 2006 VL 128 IS 3 BP 285 EP 293 DI 10.1115/1.2203108 PG 9 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 065KL UT WOS:000239158700006 ER PT J AU Ahuja, V Hosangadi, A Shipman, J Daines, R Woods, J AF Ahuja, Vineet Hosangadi, Ashvin Shipman, Jeremy Daines, Russell Woods, Jody TI Multi-element unstructured analyses of complex valve systems SO JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article AB The safe and reliable operation of high-pressure test stands for rocket engine and component testing places an increased emphasis on the performance of control valves and flow metering devices. In this paper we will present a series of high-fidelity computational analyses of systems ranging from cryogenic control valves and pressure regulator systems to cavitating venturis that are used to support rocket engine and component testing at NASA Stennis Space Center. A generalized multi-element framework with sub-models for grid adaption, grid movement, and multi-phase flow dynamics has been used to carry out the simulations. Such a framework provides the flexibility of resolving the structural and functional complexities that are typically associated with valve-based high-pressure feed systems and have been difficult to deal with using traditional computational fluid dynamics methods. Our simulations revealed a rich variety of flow phenomena such as secondary flow patterns, hydrodynamic instabilities, fluctuating vapor pockets, etc. In the paper we will discuss performance losses related to cryogenic control valves and provide insight into the physics of the dominant multi-phase fluid transport phenomena that are responsible for the "choking-like" behavior in cryogenic control elements. Additionally, we will provide detailed analyses of the modal instability that is observed in the operation of a pressure regulator valve. Such instabilities are usually not localized and manifest themselves as a system-wide phenomena leading to an undesirable chatter at high flow conditions. C1 Combust Res & Flow Technol Inc, Pipersville, PA 18947 USA. NASA, Jacobs Sverdrup NASA Test Operat Grp, Stennis Space Ctr, MS 39529 USA. RP Ahuja, V (reprint author), Combust Res & Flow Technol Inc, Pipersville, PA 18947 USA. EM vineet@craft-tech.com NR 14 TC 2 Z9 4 U1 1 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0098-2202 J9 J FLUID ENG-T ASME JI J. Fluids Eng.-Trans. ASME PD JUL PY 2006 VL 128 IS 4 BP 707 EP 716 DI 10.1115/1.2170119 PG 10 WC Engineering, Mechanical SC Engineering GA 069AZ UT WOS:000239418300007 ER PT J AU Dungan, JL AF Dungan, Jennifer L. TI Focusing on feature-based differences in map comparison SO JOURNAL OF GEOGRAPHICAL SYSTEMS LA English DT Article ID SPATIAL OBJECTS; REPRESENTATION AB Differences between two maps can be quantified using any cartometric summary; of these, feature-based statistics are potentially more relevant than pixel-based statistics. Distributions of feature areas and shape indices from the workshop maps were compared using a classic information theory index. To place differences in a significance context, uncertainty about cartometrics that arise from both the form of data model and mapping function are considered. Data model characteristics such as raster cell size, raster origin and attribute membership functions can generate variation without the existence of feature differences in the actual surfaces. Stochastic simulation can represent uncertainty due to the mapping function. An understanding of the end-to-end map generation process, absent in the workshop example, can help build a description of its space of uncertainty so that cartometric quantities can be meaningfully compared. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Dungan, JL (reprint author), NASA, Ames Res Ctr, MS 242-4, Moffett Field, CA 94035 USA. EM Jennifer.L.Dungan@nasa.gov RI Dungan, Jennifer/G-9921-2016 OI Dungan, Jennifer/0000-0002-4863-1616 NR 27 TC 23 Z9 24 U1 2 U2 3 PU SPRINGER HEIDELBERG PI HEIDELBERG PA TIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANY SN 1435-5930 J9 J GEOGR SYST JI J. Geogr. Syst. PD JUL PY 2006 VL 8 IS 2 BP 131 EP 143 DI 10.1007/s10109-006-0019-8 PG 13 WC Geography SC Geography GA 102KM UT WOS:000241809800003 ER PT J AU Sridhar, B Soni, T Sheth, K Chatterji, GB AF Sridhar, Banavar Soni, Tarun Sheth, Kapil Chatterji, Gano B. TI Aggregate flow model for air-traffic management SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB Traditionally, models used in air-traffic control and flow management are based on simulating the trajectories of individual aircraft. This approach results in models with a large number of states, which are intrinsically susceptible to errors and difficult for designing and implementing optimal strategies for traffic flow management. This paper outlines an innovative approach for the development of linear-time-variant dynamic traffic flow system models based on historical data about the behavior of air traffic. The resulting low-order, linear, robust models can be used both for the analysis and synthesis of traffic flow management techniques for current and future systems. C1 NASA, Ames Res Ctr, Automat Concepts Res Branch, Moffett Field, CA 94035 USA. Gen Dynam Corp, Mission Syst, Adv Informat Syst, Minneapolis, MN 55431 USA. Univ Calif Santa Cruz, Moffett Field, CA 94035 USA. RP Sridhar, B (reprint author), NASA, Ames Res Ctr, Automat Concepts Res Branch, Mail Stop 210-10, Moffett Field, CA 94035 USA. NR 9 TC 21 Z9 23 U1 0 U2 4 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 JUL-AUG PY 2006 VL 29 IS 4 BP 992 EP 997 DI 10.2514/1.10989 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 065YW UT WOS:000239197300024 ER PT J AU Williams, RB Inman, DJ Wilkie, WK AF Williams, R. Brett Inman, Daniel J. Wilkie, W. Keats TI Nonlinear response of the macro fiber composite actuator to monotonically increasing excitation voltage SO JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES LA English DT Article DE nonlinear piezoelectric model; macro fiber composite; electrostrictive; elastostrictive ID EQUATIONS AB A nonlinear model for a piezoelectric continuum subjected to a monotonic increase in electric field under constant mechanical load is investigated. A general model is derived and then specialized for a piezoceramic-based material with anisotropic actuation and mechanical properties, for example, the Macro Fiber Composite (MFC) actuator. This formulation includes the linear-elastic mechanical response, as well as linear and second-order piezoelectric behavior and a second-order electromechanical cross-term. Using previously published work by the same authors (Williams, R.B., Inman, D.J. and Wilkie, WK. 2004. "Tensile and Shear Behavior of Macro Fiber Composite Actuators," Journal of Composite Materials, 38(10):855-870) dealing with the mechanical response of the MFC, this set of material properties is determined experimentally in order to characterize the response of this device to given external loading conditions. C1 CALTECH, Jet Prop Lab, Struct & Mat Technol Grp, Pasadena, CA 91109 USA. Virginia Tech, Dept Mech Engn, Ctr Intelligent Mat Syst & Struct, Blacksburg, VA 24061 USA. RP Williams, RB (reprint author), CALTECH, Jet Prop Lab, Struct & Mat Technol Grp, 4800 Oak Grove Dr,MS 299-101, Pasadena, CA 91109 USA. EM rowilli6@jpl.nasa.gov NR 8 TC 28 Z9 28 U1 0 U2 6 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 JUL PY 2006 VL 17 IS 7 BP 601 EP 608 DI 10.1177/1045389X06059501 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 066QE UT WOS:000239244400005 ER PT J AU Hegazy, M Refaat, T Abedin, N Elsayed-Ali, H AF Hegazy, Mohammed Refaat, Tamer Abedin, Nurul Elsayed-Ali, Hani TI Quantum-dot Infrared Photodetector Fabricated by Pulsed Laser Deposition Technique SO JOURNAL OF LASER MICRO NANOENGINEERING LA English DT Article DE Quantum; dots; infrared; detector; PLD AB Pulsed laser deposition is used to fabricate multilayered Ge quantum-dot photodetector on Si(100). Growth was studied by reflection high-energy electron diffraction and atomic force microscopy. The difference in the current values in dark and illumination conditions was used to measure the device sensitivity to radiation. Spectral responsivity measurements reveal a peak around 2 mu m, with responsity that increases three orders of magnitude as bias increases from 0.5 to 3.5 V. C1 [Hegazy, Mohammed; Elsayed-Ali, Hani] Old Dominion Univ, Phys Elect Res Inst, Dept Elect & Comp Engn, Norfolk, VA 23529 USA. [Refaat, Tamer] NASA, Sci & Technol Corp, Langley Res Ctr, Hampton, VA 23681 USA. [Abedin, Nurul] NASA, Langley Res Ctr, Pass Sensor Syst Branch, Hampton, VA 23681 USA. RP Hegazy, M (reprint author), Old Dominion Univ, Phys Elect Res Inst, Dept Elect & Comp Engn, Norfolk, VA 23529 USA. EM helsayed@odu.edu FU US Department of Energy, Division of Materials Sciences [DE-FG0297ER45625] FX The authors would like to thank Glenn Farnsworth for his help in obtaining AFM scans. H. Elsayed-Ali would like to acknowledge the support of the US Department of Energy, Division of Materials Sciences, under Grant No. DE-FG0297ER45625. NR 11 TC 0 Z9 0 U1 0 U2 3 PU JAPAN LASER PROCESSING SOC PI OSAKA PA OSAKA UNIV, 11-1 MIHOGAOKA, IBARAKI C/O KATAYAMA LAB, JOINING & WELDING RES INST, OSAKA, 567-0047, JAPAN SN 1880-0688 J9 J LASER MICRO NANOEN JI J. Laser Micro Nanoeng. PD JUL PY 2006 VL 1 IS 2 BP 111 EP 114 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Optics; Physics, Applied SC Science & Technology - Other Topics; Materials Science; Optics; Physics GA V04KN UT WOS:000207057400005 ER PT J AU Mehr, AF Tumer, IY AF Mehr, Ali Farhang Tumer, Irem Y. TI Risk-based decision-making for managing resources during the design of complex space exploration systems SO JOURNAL OF MECHANICAL DESIGN LA English DT Article AB Complex space exploration systems are often designed in collaborative engineering environments where requirements and design decisions by various subsystem engineers have a great impact on the overall risk of the mission. As a result, the system-level management should allocate risk mitigation resources (e.g., capital to place additional sensors or to improve the current technology) among various risk elements such that the main objectives of the system are achieved as closely as possible. Minimizing risk has been long accepted as one of the major drivers for system-level decisions and particularly resource management. In this context, Risk-Based Decision Making refers to a process that allocates resources in such a way that the expected risk of the overall system is minimized. This paper presents a new risk-based design decision-making method, referred to as Risk and Uncertainty Based Concurrent Integrated Design Methodology or RUBIC Design Methodology for short. The new approach is based on concepts from portfolio optimization theory and continuous resource management, extended to provide a mathematical rigor for risk-based decision-making during the design of complex space exploration systems. The RUBIC design method is based on the idea that a unit of resource, allocated to mitigate a certain risk in the system, contributes to the overall system risk reduction in the following two ways: (1) by mitigating that particular risk; and (2) by impacting other risk elements in the system (i.e., the correlation among various risk elements). RUBIC then provides a probabilistic framework for reducing the expected risk of the final system via optimal allocation of available risk-mitigation resources. The application of the proposed approach is demonstrated using a satellite reaction wheel example. C1 NASA, Ames Res Ctr, QSS Grp, Moffett Field, CA 94035 USA. RP Mehr, AF (reprint author), NASA, Ames Res Ctr, QSS Grp, MS 269, Moffett Field, CA 94035 USA. EM amehr@email.arc.nasa.gov; itumer@email.arc.nasa.gov NR 13 TC 36 Z9 36 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 1050-0472 J9 J MECH DESIGN JI J. Mech. Des. PD JUL PY 2006 VL 128 IS 4 BP 1014 EP 1022 DI 10.1115/1.2205868 PG 9 WC Engineering, Mechanical SC Engineering GA 061PD UT WOS:000238883800042 ER PT J AU Fuss, T Ray, CS Lesher, CE Day, DE AF Fuss, T. Ray, C. S. Lesher, C. E. Day, D. E. TI In situ crystallization of lithium disilicate glass: Effect of pressure on crystal growth rate SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article DE crystallization; crystal growth; silicates; pressure effects ID DIFFERENTIAL THERMAL-ANALYSIS; SILICATE-GLASSES; FUSED-SILICA; NUCLEATION; LI2SI2O5; KINETICS; MELT; SPECTROSCOPY; VISCOSITY; SYSTEMS AB Crystallization of a Li(2)O(.)2SiO(2), (LS2) glass subjected to a uniform hydrostatic pressure of 4.5 and 6 GPa was investigated up to a temperature of 750 degrees C. The density of the compressed glass is similar to 2% greater at 4.5 GPa than 1 atm and, depending on the processing temperature, up to 10% greater at 6 GPa. Crystal growth rates investigated as a function of temperature and pressure show that lithium disilicate crystal growth is an order of magnitude slower at 4.5 GPa than 1 atm resulting in a shift of +45 degrees C (+/- 10 degrees C) in the growth rate curve at high pressure compared to 1 atm conditions. At 6 GPa lithium disilicate crystallization is suppressed entirely, while a new high pressure lithium metasilicate crystallizes at temperatures 95 degrees C (+/- 10 degrees C) higher than those reported for lithium disilicate crystallization at 1 atm. The observed decrease in crystal growth rate with increasing pressure for the lithium disilicate glass up to 750 degrees C is attributed to an increase in viscosity with pressure associated with fundamental changes in glass structure accommodating densification. (c) 2006 Elsevier B.V. All rights reserved. C1 Univ Missouri, Dept Ceram Engn, Rolla, MO 65409 USA. Univ Missouri, Grad Ctr Mat Res, Rolla, MO 65409 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Calif Davis, Dept Geol, Davis, CA 95616 USA. RP Fuss, T (reprint author), Univ Missouri, Dept Ceram Engn, Rolla, MO 65409 USA. EM Tihana.Fuss@saint-gobain.com RI Lesher, Charles/A-2468-2015 NR 53 TC 13 Z9 15 U1 3 U2 18 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD JUL 1 PY 2006 VL 352 IS 21-22 BP 2073 EP 2081 DI 10.1016/j.jnoncrysol.2006.03.005 PG 9 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA 060JZ UT WOS:000238799800003 ER PT J AU Wiemann, JM Ueno, T Leek, BT Yost, WT Schwartz, AK Hargens, AR AF Wiemann, John M. Ueno, Toshiaki Leek, Bryan T. Yost, William T. Schwartz, Alexandra K. Hargens, Alan R. TI Noninvasive measurements of intramuscular pressure using pulsed phase-locked loop ultrasound for detecting compartment syndromes - A preliminary report SO JOURNAL OF ORTHOPAEDIC TRAUMA LA English DT Article DE compartment syndrome; intramuscular pressure; pulsed phase-locked loop; slit catheter ID NEAR-INFRARED SPECTROSCOPY; DIAGNOSIS; MUSCLE; LEG AB Objectives: To develop a human model for compartment tamponade and test the efficacy of ultrasonic pulsed phase-locked loop (PPLL) fascial displacement waveform analysis for noninvasive measurement of intramuscular pressure (IMP). Design: Human subject experiment. Setting: University Level 1 trauma center. Participants: Nine male and 1 female volunteers (age 20 to 59), 3 male acute compartment syndrome (ACS) patients (age 31 to 38). Intervention: Thigh tourniquet was inflated in a stepwise fashion from 40 to 100 mm Hg to increase IMP transiently in volunteers. Main Outcome Measurements: Invasive IMP by slit catheter and PPLL fascial displacement waveform in volunteers with model ACS and patients with ACS. Results: In the model compartment tamponade group, thigh cuff occlusion increased IMP in the anterior compartment from a mean of 12.1 mm Hg (SE = 1.5) to a mean of 27.4 rnm Hg (SE = 2.4, N = 8, P < 0.0001). By fast Fourier transform, the ratio of the amplitude of the fundamental frequency to the amplitude of the second harmonic frequency of the fascial displacement waveform as measured by PPLL increased from a resting mean of 1.12 (SE = 0.07) to a mean of 1.85 (SE = 0.18) under the same protocol (N = 6, P = 0.001). Combined data with compartment syndrome patients revealed linear correlation between IMP and PPLL with an R 2 value of 0.8887. Conclusions: Subarterial thigh cuff pressure causes a significant and transient increase in IMP, serving as a model for anterior compartment tamponade. PPLL is able to detect fascial displacement waveforms corresponding to arterial pulsation and furthermore distinguishes between normal and elevated IMP. There is a linear correlation between PPLL measurements and invasive IMP. The PPLL shows potential utility as a device for noninvasive measurement of IMP for detecting compartment syndromes. C1 Univ New Mexico, Dept Orthopaed, Albuquerque, NM 87131 USA. Univ Calif San Diego, Dept Orthopaed Surg, San Diego, CA 92103 USA. NASA, Langley Res Ctr, Div Mat, Nondestruct Evaluat Sci Branch, Hampton, VA 23665 USA. RP Wiemann, JM (reprint author), Univ New Mexico, Dept Orthopaed, MSC10 5600,1, Albuquerque, NM 87131 USA. EM jwiemann@ucsd.edu NR 23 TC 15 Z9 16 U1 2 U2 6 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0890-5339 J9 J ORTHOP TRAUMA JI J. Orthop. Trauma PD JUL PY 2006 VL 20 IS 7 BP 458 EP 463 DI 10.1097/00005131-200608000-00002 PG 6 WC Orthopedics; Sport Sciences SC Orthopedics; Sport Sciences GA 073LI UT WOS:000239744000002 PM 16891936 ER PT J AU Walsh, BM Grew, GW Barnes, NP AF Walsh, Brian M. Grew, Gary W. Barnes, Norman P. TI Energy levels and intensity parameters of Ho3+ ions in Y3Al5O12 and Lu3Al5O12 SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article DE optical materials; crystal fields; luminescence ID RARE-EARTH IONS; YTTRIUM-ALUMINUM-GARNET; CRYSTAL-FIELD ANALYSIS; LANTHANUM TRIFLUORIDE; TRIVALENT HOLMIUM; ROOM-TEMPERATURE; LASER AB The energy levels of the trivalent lanthanide Ho3+ in Y3Al5O12 (YAG) and LU3Al5O12 (LuAG) have been measured. The Stark split levels for the first nine Ho manifolds in these materials have been measured, and the results have been fit to a free ion plus crystal field Hamiltonian to generate a theoretical set of energy levels. Crystal field parameters were varied to determine the best fit between experimental and theoretical energy levels. The energy levels of Ho:LuAG are seen to be very similar to those in Ho:YAG. However, subtle changes resulting from replacing Y3+ With Lu3+ in the garnet crystal Y3Al5O12 result in different transition wavelengths in LuAG. This has implications for Ho I-5(7) -> I-5(8) lasers operating at similar to 2.1 mu m. Although the energy levels have been measured previously in Ho:YAG, they have not been measured in Ho:YAG. A comparison of the energy levels in HoXAG measured here show some discrepancies with previous measurements. The consistency of the energy level placements between Ho:LuAG and Ho:YAG indicate that the earlier studies may have some errors in the assignments. Finally, a Judd-Ofelt analysis is performed on Ho:YAG and Ho:LuAG to determine the intensity parameters, and thus, the transition probabilities and branching ratios of the first eight excited manifolds. (c) 2006 Elsevier Ltd. All rights reserved. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Walsh, BM (reprint author), NASA, Langley Res Ctr, MS 468, Hampton, VA 23681 USA. EM Brian.M.Walsh@nasa.gov NR 22 TC 46 Z9 47 U1 1 U2 19 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD JUL PY 2006 VL 67 IS 7 BP 1567 EP 1582 DI 10.1016/j.jpcs.2006.01.123 PG 16 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 076RW UT WOS:000239976400033 ER PT J AU Yao, WM Amsler, C Asner, D Barnett, RM Beringer, J Burchat, PR Carone, CD Caso, C Dahl, O D'Ambrosio, G De Gouvea, A Doser, M Eidelman, S Feng, JL Gherghetta, T Goodman, M Grab, C Groom, DE Gurtu, A Hagiwara, K Hayes, KG Hernandez-Rey, JJ Hikasa, K Jawahery, H Kolda, C Kwon, Y Mangano, ML Manohar, AV Masoni, A Miquel, R Monig, K Murayama, H Nakamura, K Navas, S Olive, KA Pape, L Patrignani, C Piepke, A Punzi, G Raffelt, G Smith, JG Tanabashi, M Terning, J Tornqvist, NA Trippe, TG Vogel, P Watari, T Wohl, CG Workman, RL Zyla, PA Armstrong, B Harper, G Lugovsky, VS Schaffner, PS Artuso, M Babu, KS Band, HR Barberio, E Battaglia, M Bichel, H Biebel, O Bloch, P Blucher, E Cahn, RN Casper, D Cattai, A Ceccucci, A Chakraborty, D Chivukula, RS Cowan, G Damour, T De Grand, T Desler, K Dobbs, MA Drees, M Edwards, A Edwards, DA Elvira, VD Erler, J Fetscher, W Fields, BD Foster, B Froidevaux, D Gaisser, TK Garren, L Gerber, HJ Gerbier, G Gibbons, L Gilman, FJ Giudice, GF Gritsan, AV Grunewald, M Haber, HE Hagmann, C Hinchliffe, I Hocker, A Igo-Kemenes, P Jackson, JD Johnson, KF Karlen, D Kayser, B Kirkby, D Klein, SR Kleinknecht, K Knowles, JG Kowalewski, RV Kreitz, P Krusche, B Kuyanov, YV Lahav, O Langacker, P Liddle, A Ligeti, Z Liss, TM Littenberg, L Liu, JC Lugovsky, KS Lugovsky, SB Mannel, T Marciano, WJ Martin, AD Milstead, D Narain, M Nason, P Nir, Y Peacock, JA Prell, SA Quadt, A Raby, S Ratcliff, BN Razuvaev, EA Renk, B Richardson, PR Roesler, S Rolandi, G Roman, MT Rosenberg, LJ Sachrajda, CT Sakai, Y Sarkar, S Schmitt, M Schneider, O Scott, D Sjostrand, T Smoot, GF Sokolsky, P Spanier, S Spieler, H Stahl, A Staney, T Streitmatter, RE Sumiyoshi, T Tkachenko, NP Trilling, GH Valencia, G van Bibber, K Vincter, MG Ward, DR Webber, BR Wells, JD Whalley, M Wolfenstein, L Womersley, J Woody, CL Yamamoto, A Zenin, OV Zhang, J Zhu, RY AF Yao, W-M Amsler, C. Asner, D. Barnett, R. M. Beringer, J. Burchat, P. R. Carone, C. D. Caso, C. Dahl, O. D'Ambrosio, G. De Gouvea, A. Doser, M. Eidelman, S. Feng, J. L. Gherghetta, T. Goodman, M. Grab, C. Groom, D. E. Gurtu, A. Hagiwara, K. Hayes, K. G. Hernandez-Rey, J. J. Hikasa, K. Jawahery, H. Kolda, C. Kwon, Y. Mangano, M. L. Manohar, A. V. Masoni, A. Miquel, R. Moenig, K. Murayama, H. Nakamura, K. Navas, S. Olive, K. A. Pape, L. Patrignani, C. Piepke, A. Punzi, G. Raffelt, G. Smith, J. G. Tanabashi, M. Terning, J. Toernqvist, N. A. Trippe, T. G. Vogel, P. Watari, T. Wohl, C. G. Workman, R. L. Zyla, P. A. Armstrong, B. Harper, G. Lugovsky, V. S. Schaffner, P. S. Artuso, M. Babu, K. S. Band, H. R. Barberio, E. Battaglia, M. Bichel, H. Biebel, O. Bloch, P. Blucher, E. Cahn, R. N. Casper, D. Cattai, A. Ceccicco, A. Chakraborty, D. Chivukula, R. S. Cowan, G. Damour, T. De Grand, T. Desler, K. Dobbs, M. A. Drees, M. Edwards, A. Edwards, D. A. Elvira, V. D. Erler, J. Fetscher, W. Fields, B. D. Foster, B. Froidevaux, D. Gaisser, T. K. Garren, L. Gerber, H. J. Gerbier, G. Gibbons, L. Gilman, F. J. Giudice, G. F. Gritsan, A. V. Grunewald, M. Haber, H. E. Hagmann, C. Hinchliffe, I. Hocker, A. Igo-Kemenes, P. Jackson, J. D. Johnson, K. F. Karlen, D. Kayser, B. Kirkby, D. Klein, S. R. Kleinknecht, K. Knowles, J. G. Kowalewski, R. V. Kreitz, P. Krusche, B. Kuyanov, Y. V. Lahav, O. Langacker, P. Liddle, A. Ligeti, Z. Liss, T. M. Littenberg, L. Liu, J. C. Lugovsky, K. S. Lugovsky, S. B. Mannel, T. Marciano, W. J. Martin, A. D. Milstead, D. Narain, M. Nason, P. Nir, Y. Peacock, J. A. Prell, S. A. Quadt, A. Raby, S. Ratcliff, B. N. Razuvaev, E. A. Renk, B. Richardson, P. R. Roesler, S. Rolandi, G. Roman, M. T. Rosenberg, L. J. Sachrajda, C. T. Salao, Y. Sarkar, S. Schmitt, M. Schneider, O. Scott, D. Sjostrand, T. Smoot, G. F. Sokolsky, P. Spanier, S. Spieler, H. Stahl, A. Staney, T. Streitmatter, R. E. Sumiyoshi, T. Tkachenko, N. P. Trilling, G. H. Valencia, G. van Bibber, K. Vincter, M. G. Ward, D. R. Webber, B. R. Wells, J. D. Whalley, M. Wolfenstein, L. Womersley, J. Woody, C. L. Yamamoto, A. Zenin, O. V. Zhang, J. Zhu, R. Y. CA Particle Data Grp TI Review of particle physics SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article AB This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2633 new measurements from 689 papers, we list, evaluate, and average measured properties of guage bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. among the 110 reviews are many that are new or heavily revised including those on CKM quark-mixing, V-ud & V-us, V-cb & V-ub, top quark, muon anomalous magnetic moment, extra dimensions, particle detectors, cosmic background radiation, dark matter, cosmological parameters, and big bang cosmology. C1 Lawrence Berkeley Natl Lab, Div Phys, Berkeley, CA 94720 USA. Univ Zurich, Inst Phys, CH-8057 Zurich, Switzerland. Carleton Univ, Dept Phys, Ottawa, ON K1S 5B6, Canada. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Coll William & Mary, Dept Phys, Nucl & Particle Theory Grp, Williamsburg, VA 23187 USA. Univ Genoa, Dipartimento Fis, I-16146 Genoa, Italy. Univ Genoa, Ist Nazl Fis Nucl, I-16146 Genoa, Italy. Univ Naples Federico II, Ist Nazl Fis Nucl, Sez Napoli, I-80126 Naples, Italy. Univ Naples Federico II, Dipartimento Sci Fis, Sez Napoli, I-80126 Naples, Italy. Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. CERN, European Org Nucl Res, CH-1211 Geneva 23, Switzerland. Budker Inst Nucl Phys, RU-630090 Novosibirsk, Russia. Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA. Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Argonne Natl Lab, Argonne, IL 60439 USA. ETH, Inst Particle Phys, CH-8093 Zurich, Switzerland. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. High Energy Accelerator Res Org, KEK, Tsukuba, Ibaraki 3050801, Japan. Hillsdale Coll, Dept Phys, Hillsdale, MI 49242 USA. Univ Valencia, Inst Fis Corpuscular, CSIC, E-46071 Valencia, Spain. Tohoku Univ, Dept Phys, Aoba Ku, Sendai, Miyagi 9808578, Japan. Univ Maryland, Dept Phys & Astron, College Pk, MD 20742 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Yonsei Univ, Dept Phys, Seoul 120749, South Korea. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Cittadella Univ Monserrato, Ist Nazl Fis Nucl, Sez Cagliari, I-09042 Moserrato, CA, Italy. DESY, D-15735 Zeuthen, Germany. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Granada, Dept Fis Teor & Cosmos, E-18071 Granada, Spain. Univ Granada, CAFPE, E-18071 Granada, Spain. Univ Alabama, Dept Phys & Astron, Tuscaloosa, AL 35487 USA. Univ Pisa, Ist Nazl Fis Nucl, I-56127 Pisa, Italy. Univ Pisa, Dipartimento Fis, I-56127 Pisa, Italy. Max Planck Inst Phys & Astrophys, Werner Heisenberg Inst Phys, D-80805 Munich, Germany. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Helsinki, Dept Phys Sci, FIN-00014 Helsinki, Finland. CALTECH, Kellogg Radiat Lab 106 38, Pasadena, CA 91125 USA. George Washington Univ, Dept Phys, Ashburn, VA 20147 USA. Inst High Energy Phys, COMPAS Grp, RU-142284 Protvino, Russia. Syracuse Univ, Dept Phys, Syracuse, NY 13244 USA. Oklahoma State Univ, Dept Phys, Stillwater, OK 74078 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Univ Melbourne, Sch Phys, Parkville, Vic 3052, Australia. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Univ Munich, Dept Phys, D-80799 Munich, Germany. Univ Chicago, Chicago, IL 60637 USA. No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. Univ London Royal Holloway & Bedford New Coll, Dept Phys, Egham TW20 0EX, Surrey, England. Inst Hautes Etud Sci, F-91440 Bures Sur Yvette, France. DESY, D-22603 Hamburg, Germany. McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada. Univ Bonn, Inst Phys, D-53115 Bonn, Germany. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Nacl Autonoma Mexico, Inst Fis, Mexico City 01000, DF, Mexico. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Oxford, Dept Phys, Oxford OX1 3RH, England. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. CEA Saclay, F-91191 Gif Sur Yvette, France. Cornell Univ, Newman Lab Elementary Particle Phys, Ithaca, NY 14853 USA. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Coll Dublin, UCD Sch Phys, Dublin 4, Ireland. Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Heidelberg Univ, Inst Phys, D-69120 Heidelberg, Germany. Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. Univ Victoria, Victoria, BC V8W 3P6, Canada. Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Johannes Gutenberg Univ Mainz, Inst Phys, D-55099 Mainz, Germany. Univ Edinburgh, Inst Astron, Royal Observ, Edinburgh EH9 3JZ, Midlothian, Scotland. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. Univ Sussex, Ctr Astron, Brighton BN1 9RH, E Sussex, England. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Siegen, Fachbereich Phys, D-57068 Siegen, Germany. Kent State Univ, Dept Phys, Kent, OH 44242 USA. Univ Durham, Inst Particle Phys Phenomenol, Dept Phys, Durham DH1 3LE, England. AlbaNova Univ Ctr, Stockholm Univ, SE-10691 Stockholm, Sweden. Boston Univ, Dept Phys, Boston, MA 02215 USA. Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy. Weizmann Inst Sci, Dept Particle Phys, IL-76100 Rehovot, Israel. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. Univ Rochester, Rochester, NY 14627 USA. Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. MIT, Dept Phys & Lab Nucl Sci, Cambridge, MA 02139 USA. Univ Southampton, Sch Phys & Astron, Southampton SO17 1BJ, Hants, England. Univ Oxford, Rudolf Peierls Ctr Theoret Phys, Oxford OX1 3NP, England. Ecole Polytech Fed Lausanne, CH-1015 Lausanne, Switzerland. Univ British Columbia, Dept Phys & Astron, Vancouver, BC V6T 1Z1, Canada. Lund Univ, Dept Theoret Phys, S-22362 Lund, Sweden. Univ Utah, Dept Phys, Salt Lake City, UT 84112 USA. Rhein Westfal TH Aachen, Physikzentrum, Inst Phys 3, D-52056 Aachen, Germany. NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. High Energy Accel Res Org, Tsukuba, Ibaraki 3050801, Japan. Univ Cambridge, Cavendish Lab, Cambridge CB3 0HE, England. Univ Michigan, Michigan Ctr Theoret Phys, Dept Phys, Ann Arbor, MI 48109 USA. Rutherford Appleton Lab, CCLRC, Didcot OX11 0QX, Oxon, England. Chinese Acad Sci, IHEP, Beijing 100049, Peoples R China. CALTECH, Dept Phys 256 48, Pasadena, CA 91125 USA. RP Yao, WM (reprint author), Lawrence Berkeley Natl Lab, Div Phys, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Stahl, Achim/E-8846-2011; Chivukula, R. Sekhar/C-3367-2012; Patrignani, Claudia/C-5223-2009; Punzi, Giovanni/J-4947-2012; Murayama, Hitoshi/A-4286-2011; Rolandi, Luigi (Gigi)/E-8563-2013; Hernandez-Rey, Juan Jose/N-5955-2014; Sarkar, Subir/G-5978-2011; Navas, Sergio/N-4649-2014; OI Olive, Keith/0000-0001-7201-5998; Scott, Douglas/0000-0002-6878-9840; Sjostrand, Torbjorn/0000-0002-7630-8605; Watari, Taizan/0000-0002-8879-1008; Miquel, Ramon/0000-0002-6610-4836; Stahl, Achim/0000-0002-8369-7506; Chivukula, R. Sekhar/0000-0002-4142-1077; Patrignani, Claudia/0000-0002-5882-1747; Punzi, Giovanni/0000-0002-8346-9052; Rolandi, Luigi (Gigi)/0000-0002-0635-274X; Hernandez-Rey, Juan Jose/0000-0002-1527-7200; Sarkar, Subir/0000-0002-3542-858X; Navas, Sergio/0000-0003-1688-5758; Webber, Bryan/0000-0001-7474-0990; Nason, Paolo/0000-0001-9250-246X NR 4 TC 3864 Z9 3894 U1 53 U2 243 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 EI 1361-6471 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD JUL PY 2006 VL 33 IS 1 SI SI BP 1 EP + DI 10.1088/0954-3899/33/1/001 PG 1211 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 077FC UT WOS:000240012400001 ER PT J AU Hofer, RR Jankovsky, RS Gallimore, AD AF Hofer, Richard R. Jankovsky, Robert S. Gallimore, Alec D. TI High-specific impulse Hall thrusters, Part 1: Influence of current density and magnetic field SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID STATIONARY PLASMA THRUSTERS; CLOSED-DRIFT THRUSTERS; PERFORMANCE; MODEL; WALL AB A laboratory-model Hall thruster with a magnetic circuit designed for high-specific impulse (2000-3000 s) was evaluated to determine how current density and magnetic field affect thruster operation. Results have shown for the first time that a minimum current density and optimum magnetic field shape exist at which efficiency will monotonically increase with specific impulse. At the nominal mass How rate of 10 mg/s and between discharge voltages of 300 and 1000 V, total specific impulse and total efficiency ranged from 1600 to 3400 s and 51 to 61%, respectively. Comparison with a similar thruster showed how efficiency can be optimized for specific impulse by varying the shape of the magnetic field. Plume divergence decreased from a maximum of 48 deg at 400 V to a minimum of 35. deg at 1000 V, but increased between 300 and 400 V as the likely result of a large increase in)discharge current oscillations. The breathing-mode frequency continuously increased with voltage, from 14.5 kHz at 300 V to 22 kHz at 1000 V, in contrast to other Hall thrusters where a sharp decrease of the breathing-mode frequency was found to coincide with increasing electron current and decreasing efficiency. These findings suggest that efficient, high-specific impulse operation was enabled through the regulation of the electron current with the applied magnetic field. C1 QSS Grp Inc, Elect Prop Branch, Cleveland, OH USA. NASA, John H Glenn Res Ctr, Elect Prop Branch, Cleveland, OH 44135 USA. Univ Michigan, Dept Aerosp Engn, Plasmadynam & Elect Prop Lab, Ann Arbor, MI 48109 USA. RP Hofer, RR (reprint author), QSS Grp Inc, Elect Prop Branch, Cleveland, OH USA. EM richard.r.hofer@jpl.nasa.gov; robert.s.jankovsky@nasa.gov; alee.gallimore@umich.edu NR 58 TC 35 Z9 37 U1 1 U2 9 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 JUL-AUG PY 2006 VL 22 IS 4 BP 721 EP 731 DI 10.2514/1.15952 PG 11 WC Engineering, Aerospace SC Engineering GA 064RQ UT WOS:000239107200002 ER PT J AU Hofer, RR Gallimore, AD AF Hofer, Richard R. Gallimore, Alec D. TI High-specific impulse Hall thrusters, Part 2: Efficiency analysis SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT AIAA/ASME/SAE/ASEE 40th Joint Propulsion Conference CY JUL 11-15, 2004 CL Ft Lauderdale, FL SP Amer Inst Aeronaut & Astronaut, ASME, SAE, ASEE ID STATIONARY PLASMA THRUSTERS; CLOSED-DRIFT THRUSTERS; ION-ENERGY; WALL; SPT-100; PLUME; CONDUCTIVITY; OSCILLATIONS; PERFORMANCE AB Performance and plasma measurements of a high-specific impulse (2000-3000 s) Hall thruster were analyzed using a phenomenological performance model that accounted for a partially ionized plasma containing multiply charged ions. Anode efficiency over discharge voltages of 300-900 V ranged from 57 to 69%, which corresponded to 89-97% voltage utilization, 86-90% mass utilization, 77-81% current utilization, and 97-99% charge utilization. Although the net decrease of efficiency due to multiply charged ions was at most 3%, the effects of multiply charged ions on the discharge current could not be neglected because the increase of the discharge current with voltage was primarily due to the increasing fraction of multiply charged ions. This and the fact that the maximum deviation of the electron current from its average value was only +5/-14% illustrated how efficient operation at high-specific impulse was enabled through the regulation of the electron current with the applied magnetic field. The electron Hall parameter, defined by acceleration zone plasma properties, was nearly constant with voltage, decreasing from an average of 210 at 300 V to an average of 160 between 400 to 900 V. C1 QSS Grp Inc, Cleveland, OH 44135 USA. Univ Michigan, Dept Aerosp Engn, Plasmadynam & Elect Prop Lab, Ann Arbor, MI 48109 USA. RP Hofer, RR (reprint author), NASA, Glenn Res Ctr, Elect Prop Branch, Cleveland, OH 44135 USA. EM richard.r.hofer@jpl.nasa.gov; alec.gallimore@umich.edu NR 54 TC 35 Z9 37 U1 2 U2 14 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 JUL-AUG PY 2006 VL 22 IS 4 BP 732 EP 740 DI 10.2514/1.15954 PG 9 WC Engineering, Aerospace SC Engineering GA 064RQ UT WOS:000239107200003 ER PT J AU Lian, YS Liou, MS AF Lian, Yongsheng Liou, Meng-Sing TI Aerostructural optimization of a transonic compressor rotor SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID DESIGN OPTIMIZATION; MULTIDISCIPLINARY OPTIMIZATION; MULTIOBJECTIVE OPTIMIZATION; EVOLUTIONARY ALGORITHM; VIBRATION REDUCTION AB This paper presents a framework for multi-objective and multidisciplinary design optimization using high-fidelity analysis tools. In this framework the aerodynamic performance is evaluated based-on a Navier-Stokes equation solver, and the structure dynamics is computed using commercially available finite element software. We employ a genetic algorithm as a robust design optimization tool to facilitate the multi-objective optimization. We also use the response surface approach to tackle the difficulties associated with the organizational complexity and computational burden inherent in the multidisciplinary optimization. The coupling between the fluid solver and structural solver is realized through a thin-plate spline interpolation algorithm. The proposed approach is then used to perform aerostructural optimization of a three-dimensional transonic compressor blade. Our numerical results show that this method can improve the existing design and reduce the required computational time by orders of magnitude. C1 Ohio Aerosp Inst, Cleveland, OH 44142 USA. NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Lian, YS (reprint author), Univ Michigan, Ann Arbor, MI 48109 USA. EM ylian@umich.edu NR 27 TC 12 Z9 12 U1 2 U2 8 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 JUL-AUG PY 2006 VL 22 IS 4 BP 880 EP 888 DI 10.2514/1.15397 PG 9 WC Engineering, Aerospace SC Engineering GA 064RQ UT WOS:000239107200021 ER PT J AU Chen, GA Yang, P Kattawar, GW Mishchenko, MI AF Chen, GA Yang, P Kattawar, GW Mishchenko, MI TI Scattering phase functions of horizontally oriented hexagonal ice crystals SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article; Proceedings Paper CT 8th Conference on Electromagnetic and Light Scattering by Nonspherical Particles CY MAY 16-20, 2005 CL Granada, SPAIN DE FDTD; T-matrix; phase matrix; horizontal orientation; hexagon; cylinder ID CIRRUS CLOUDS; DIELECTRIC PARTICLES; RADIATIVE-TRANSFER; SINGLE-SCATTERING; LIGHT-SCATTERING; T-MATRIX; CYLINDERS; COLUMNS AB Finite-difference time domain (FDTD) solutions are first compared with the corresponding T-matrix results for light scattering by circular cylinders with specific orientations. The FDTD method is then utilized to study the scattering properties of horizontally oriented hexagonal ice plates at two wavelengths, 0.55 and 12 mu m. The phase functions of horizontally oriented ice plates deviate substantially from their counterparts obtained for randomly oriented particles. Furthermore, we compute the phase functions of horizontally oriented ice crystal columns by using the FDTD method along with two schemes for averaging over the particle orientations. It is shown that the phase functions of hexagonal ice columns with horizontal orientations are not sensitive to the rotation about the principal axes of the particles. Moreover, hexagonal ice crystals and circular cylindrical ice particles have similar optical properties, particularly, at a strongly absorbing wavelength, if the two particle geometries have the same length and aspect ratio defined as the ratio of the radius or semi-width of the cross section of a particle to its length. The phase functions for the two particle geometries are slightly different in the case of weakly absorbing plates with large aspect ratios. However, the solutions for circular cylinders agree well with their counterparts for hexagonal columns. (c) 2005 Elsevier Ltd. All rights reserved. C1 Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Yang, P (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; Mishchenko, Michael/D-4426-2012 NR 22 TC 6 Z9 7 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUL-AUG PY 2006 VL 100 IS 1-3 BP 91 EP 102 DI 10.1016/j.jqsrt.2005.11.029 PG 12 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 033ZF UT WOS:000236892800009 ER PT J AU Dlugach, JM Mishchenko, MI AF Dlugach, JM Mishchenko, MI TI Enhanced backscattering of polarized light: Effect of particle nonsphericity on the helicity-preserving enhancement factor SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article; Proceedings Paper CT 8th Conference on Electromagnetic and Light Scattering by Nonspherical Particles CY MAY 16-20, 2005 CL Granada, SPAIN DE enhancement factor; coherent backscattering; polarization; nonspherical particles ID DISCRETE RANDOM-MEDIA; MULTIPLE-SCATTERING; COHERENT BACKSCATTERING; SPHERICAL-PARTICLES; WEAK-LOCALIZATION; DISORDERED MEDIA; DEPOLARIZATION AB We analyze theoretically the effect of particle nonsphericity on the backscattering enhancement factor zeta(hp) in the helicity-preserving channel. Using numerically exact T-matrix and vector radiative-transfer codes, we have performed computations for optically semi-infinite homogeneous layers composed of polydisperse, randomly oriented oblate spheroids with the real part of the refractive index equal to 1.2, 1.4, and 1.6, the imaginary part of the refractive index equal to 0 and 0.01, various values of the equal-surface-area-sphere effective size parameter, and aspect ratios 1 <=epsilon <= 2. Our computations demonstrate that whereas for spheres zeta(hp) equivalent to 2, for spheroids the helicity-preserving enhancement factor can deviate quite significantly from the value 2. The magnitude of this deviation varies substantially with particle microphysical parameters and illumination geometry. (c) 2005 Elsevier Ltd. All rights reserved. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Natl Acad Sci Ukraine, Main Astron Observ, UA-03680 Kiev, Ukraine. RP Mishchenko, MI (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM crmim@giss.nasa.gov RI Mishchenko, Michael/D-4426-2012 NR 26 TC 5 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUL-AUG PY 2006 VL 100 IS 1-3 BP 115 EP 121 DI 10.1016/j.jqsrt.2005.11.060 PG 7 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 033ZF UT WOS:000236892800011 ER PT J AU Mishchenko, MI AF Mishchenko, MI TI Far-field approximation in electromagnetic scattering SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article; Proceedings Paper CT 8th Conference on Electromagnetic and Light Scattering by Nonspherical Particles CY MAY 16-20, 2005 CL Granada, SPAIN DE electromagnetic scattering; scattering by particles; far-field approximation ID RADIATIVE-TRANSFER AB The volume integral equation formalism is used to derive and analyze specific criteria of applicability of the far-field approximation in electromagnetic scattering by a finite three-dimensional object. in the case of wavelength-sized and larger objects, this analysis leads to a natural subdivision of the entire external space into a near-field zone, a transition zone, and a far-field zone. It is demonstrated that the general criteria of far-field scattering are consistent with the theory and practice of T-matrix computations. (c) 2005 Elsevier Ltd. All rights reserved. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Mishchenko, MI (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM crmim@giss.nasa.gov RI Mishchenko, Michael/D-4426-2012 NR 14 TC 17 Z9 17 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUL-AUG PY 2006 VL 100 IS 1-3 BP 268 EP 276 DI 10.1016/j.jqsrt.2005.11.044 PG 9 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 033ZF UT WOS:000236892800027 ER PT J AU Sun, WB Lin, B AF Sun, WB Lin, B TI Optical characterization of metallic aerosols SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article; Proceedings Paper CT 8th Conference on Electromagnetic and Light Scattering by Nonspherical Particles CY MAY 16-20, 2005 CL Granada, SPAIN DE light scattering; metallic aerosol; environmental protection ID TIME-DOMAIN SOLUTION; LIGHT-SCATTERING; ABSORBING MEDIUM; ABSORPTION; PARTICLES; GRAINS AB Airborne metallic particulates from industry and urban sources are highly conducting aerosols. The characterization of these pollutant particles is important for environment monitoring and protection. Because these metallic particulates are highly reflective, their effect on local weather or regional radiation budget may also need to be studied. In this work, light scattering characteristics of these metallic aerosols are studied using exact solutions on perfectly conducting spherical and cylindrical particles. It is found that for perfectly conducting spheres and cylinders, when scattering angle is larger than similar to 90 degrees the linear polarization degree of the scattered light is very close to zero. This light scattering characteristics of perfectly conducting particles is significantly different from that of other aerosols. When these perfectly conducting particles are immersed in an absorbing medium, this light scattering characteristics does not show significant change. Therefore, measuring the linear polarization of scattered lights at backward scattering angles can detect and distinguish metallic particulates from other aerosols. This result provides a great potential of metallic aerosol detection and monitoring for environmental protection. (c) 2005 Elsevier Ltd. All rights reserved. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. RP Sun, WB (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. EM w.sun@larc.nasa.gov NR 16 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUL-AUG PY 2006 VL 100 IS 1-3 BP 359 EP 372 DI 10.1016/j.jqsrt.2005.11.075 PG 14 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 033ZF UT WOS:000236892800035 ER PT J AU Xie, Y Yang, P Gao, BC Kattawar, GW Mishchenko, MI AF Xie, Y Yang, P Gao, BC Kattawar, GW Mishchenko, MI TI Effect of ice crystal shape and effective size on snow bidirectional reflectance SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article; Proceedings Paper CT 8th Conference on Electromagnetic and Light Scattering by Nonspherical Particles CY MAY 16-20, 2005 CL Granada, SPAIN ID RADIATIVE-TRANSFER; PHASE FUNCTIONS; MULTIPLE-SCATTERING; OPTICAL-PROPERTIES; LIGHT-SCATTERING; CLOUDS; TRANSMISSION; SURFACES; EQUATION; CIRRUS AB We tested the applicability of three rigorous radiative transfer computational approaches, namely, the discrete ordinates radiative transfer (DISORT) method, the adding-doubling approach, and an efficient computational technique based on Ambartsumian's nonlinear integral equation for computing the bidirectional reflectance of a semi-infinite layer. It was found that each of these three models, in a combination with the truncation of the forward peak of the bulk scattering phase functions of ice particles, can be used to simulate the bidirectional reflectance of a semi-infinite snow layer with appropriate accuracy. Furthermore, we investigate the sensitivity of the bidirectional reflectance of a homogeneous and optically infinite snow layer to ice crystal habit and effective particle size. It is shown that the bidirectional reflectance is not sensitive to the particle effective size in the visible spectrum. The sensitivity of the bidirectional reflectance in the near-infrared spectrum to the particle effective size increases with the increase of the incident wavelength. The sensitivity of the bidirectional reflectance to the effective particle size and shape is attributed fundamentally to the sensitivity of the single-scattering properties to particle size and shape. For a specific ice crystal habit, the truncated phase function used in the radiative transfer computations is not sensitive to particle effective size. Thus, the single-scattering albedo is primarily responsible for the sensitivity of the bidirectional reflectance to particle size, particularly, at a near-infrared wavelength. (c) 2005 Elsevier Ltd. All rights reserved. C1 Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Yang, P (reprint author), Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. EM pyang@ariel.met.tamu.edu RI Xie, Yu/A-4266-2011; Yang, Ping/B-4590-2011; Mishchenko, Michael/D-4426-2012 NR 30 TC 31 Z9 34 U1 2 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUL-AUG PY 2006 VL 100 IS 1-3 BP 457 EP 469 DI 10.1016/j.jqsrt.2005.11.056 PG 13 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 033ZF UT WOS:000236892800044 ER PT J AU You, Y Kattawar, GW Yang, P Hu, YX Baum, BA AF You, Y Kattawar, GW Yang, P Hu, YX Baum, BA TI Sensitivity of depolarized lidar signals to cloud and aerosol particle properties SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article; Proceedings Paper CT 8th Conference on Electromagnetic and Light Scattering by Nonspherical Particles CY MAY 16-20, 2005 CL Granada, SPAIN DE space-borne lidar; CALIPSO; depolarization; clouds; particle shape ID SCATTERING; ICE; POLARIZATION; ABSORPTION; PHASE AB Measurements from depolarized lidars provide a promising method to retrieve both cloud and aerosol properties and a versatile complement to passive satellite-based sensors. For lidar observations of clouds and aerosols, multiple scattering plays an important role in the scattering process. Monte Carlo simulations are carried out to investigate the sensitivity of lidar backscattering depolarization to cloud and aerosol properties. Lidar parameters are chosen to be similar to those of the upcoming space-based CALIPSO lidar. Cases are considered that consist of a single cloud or aerosol layer, as well as a case in which cirrus clouds overlay different types of aerosols. It is demonstrated that besides thermodynamic cloud phase, the depolarized lidar signal may provide additional information on ice or aerosol particle shapes. However, our results show little sensitivity to ice or aerosol particle sizes. Additionally, for the case of multiple but overlapping layers involving both clouds and aerosols, the depolarized lidar contains information that can help identify the particle properties of each layer. (c) 2005 Elsevier Ltd. All rights reserved. C1 Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP You, Y (reprint author), Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. RI Yang, Ping/B-4590-2011; Baum, Bryan/B-7670-2011; Hu, Yongxiang/K-4426-2012 OI Baum, Bryan/0000-0002-7193-2767; NR 19 TC 22 Z9 25 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUL-AUG PY 2006 VL 100 IS 1-3 BP 470 EP 482 DI 10.1016/j.jqsrt.2005.11.058 PG 13 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 033ZF UT WOS:000236892800045 ER PT J AU Tripsanas, EK Bryant, WR Slowey, NC Kim, JW AF Tripsanas, Efthymios K. Bryant, William R. Slowey, Niall C. Kim, Jin Wook TI Marine isotope stage 6 canyon and spillover deposits of the Bryant and Eastern canyon systems, northwest Gulf of Mexico: Importance of fine-grained turbidites on a delta-fed prograding slope SO JOURNAL OF SEDIMENTARY RESEARCH LA English DT Article ID DEEP-SEA FAN; NAVY SUBMARINE FAN; CONTINENTAL-SLOPE; SEDIMENT WAVES; SETTLING VELOCITY; MEDITERRANEAN-SEA; BRITISH-COLUMBIA; PHYSICAL MODEL; DRAG REDUCTION; MONTEREY FAN AB A large set of long sediment cores and high-resolution seismic-reflection data were used to study the sedimentology of the delta-fed prograding slope of the northwest Gulf of Mexico, during Marine Isotope Stage (MIS) 6 (125-180 ka). Bryant and Eastern canyon systems were the main pathways during this period through which Mississippi River sediment was delivered down the continental slope. Two MIS 6 sedimentary environments have been defined on the slope of the northwest Gulf of Mexico: intracanyon and overbank environments. The erosional action of turbidity currents in Bryant and Eastern canyons was focused mainly on the thalweg, whereas, on the rest of the canyon floors, the flows acquired a mainly depositional character, resulting in the formation of inner levees and terraces. MIS 6 deposits in overbank environments consist entirely of thick (> 50 m), widespread (> 15-20 km), and continuous successions of mud turbidites, which indicate that spillover processes were dominant along Bryant and Eastern canyons. The total absence of bioturbation structures and hemipelagic sediments in MIS 6 overbank deposits indicate high sedimentation rates exceeding 200-600 cm/ky. The majority of the overbank deposits are normally graded, indicating that most of the turbidity currents during MIS 6 resulted from sediment failures on the outer shelf and upper continental slope. Sedimentological observations indicate that a complete mud turbidite sequence (T0-8 sequence in the nomenclature of Stow and Shanmugam 1980) results from a waning low-density turbidity current consisting of four successive flow-regime stages: (1) an initial erosional stage (>= 30 cm/s), (2) deposition of the coarsest, noncohesive fraction (silt) of the suspended sediment in the flows (30-100 cm/s), (3) cyclic deposition of cohesive (mud) and noncohesive (silt) laminae due to fluctuations in the shear stress in the boundary layer of the flow (12-30 cm/s), and (4) deposition from a silt-depleted and slowly moving (<= 15 cm/s) sediment cloud. C1 Texas A&M Univ, Dept Oceanog, College Stn, TX 77843 USA. Fisheries & Oceans Canada, Bedford Inst Oceanog, Dartmouth, NS B2Y 4A2, Canada. USN, Res Lab, Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. RP Tripsanas, EK (reprint author), Texas A&M Univ, Dept Oceanog, College Stn, TX 77843 USA. EM etripsan@nrcan.gc.ca NR 72 TC 5 Z9 5 U1 2 U2 5 PU SEPM-SOC SEDIMENTARY GEOLOGY PI TULSA PA 6128 EAST 38TH ST, STE 308, TULSA, OK 74135-5814 USA SN 1527-1404 EI 1938-3681 J9 J SEDIMENT RES JI J. Sediment. Res. PD JUL-AUG PY 2006 VL 76 IS 7-8 BP 1012 EP 1034 DI 10.2110/jsr.2006.083 PG 23 WC Geology SC Geology GA 090OD UT WOS:000240959700004 ER PT J AU McGuire, MA Schmidt, AM Gascoin, F Snyder, GJ DiSalvo, FJ AF McGuire, MA Schmidt, AM Gascoin, F Snyder, GJ DiSalvo, FJ TI Thermoelectric and structural properties of a new Chevrel phase: Ti0.3Mo5RuSe8 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article DE Chevrel phase; titanium molybdenum ruthenium selenide; molybdenum ruthenium selenide; thermoelectric; electrical resistivity; Seebeck coefficient; powder X-ray diffraction; Rietveld refinement ID MOLYBDENUM; OXYGEN; INTERCALATION; CLUSTERS; LOCATION; NETWORK; FE; NI; TI AB The new Chevrel phase Ti0.3Mo5RuSe8 has been synthesized and characterized by quantitative microprobe analysis, powder X-ray diffraction, and high-temperature thermoelectric properties measurements. The thermoelectric properties of this compound are compared to the previously reported data for other related Chevrel phases. We report also the results of Rietveld analysis of powder X-ray diffraction data for Ti0.3Mo5RuSe8. This compound adopts the rhombohedral Chevrel phase structure (space group R (3) over bar, Z = 3) with hexagonal lattice constants a = 9.75430(25) angstrom and c = 10.79064(40) angstrom. The low level of incorporation and low scattering power of Ti precluded the identification of the Ti positions, and Rietveld refinement was carried out only for the Mo5RuSe8 framework of Ti0.3Mo5RuSe8 (R-p = 10.5%, R-wp = 14.6%). Rietveld analysis was also used to refine the structure of the unfilled phase Mo5RuSe8 (R (3) over bar Z = 3, a = 9.63994(8) angstrom, c = 10.97191(11) angstrom, R-p = 8.0%, R-wp = 10.5%). Comparisons between the two structures are made. (C) 2006 Elsevier Inc. All rights reserved. C1 Cornell Univ, Baker Lab, Dept Chem & Biol Chem, 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, Baker Lab, Dept Chem & Biol Chem, Ithaca, NY 14853 USA. EM fjd3@cornell.edu RI McGuire, Michael/B-5453-2009; Snyder, G. Jeffrey/E-4453-2011; Snyder, G/I-2263-2015 OI McGuire, Michael/0000-0003-1762-9406; Snyder, G. Jeffrey/0000-0003-1414-8682; NR 30 TC 8 Z9 8 U1 0 U2 7 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 JUL PY 2006 VL 179 IS 7 BP 2158 EP 2163 DI 10.1016/j.jssc.2006.04.022 PG 6 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 057ZM UT WOS:000238633700030 ER PT J AU Johnston, JD Blandino, JR McEvoy, KC AF Johnston, John D. Blandino, Joseph R. McEvoy, Kiley C. TI Analytical and experimental characterization of gravity-induced deformations in subscale gossamer structures 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 The development of gossamer space structures such, as solar sails and sunshields presents many challenges due to their large size and extreme flexibility. The postdeployment structural geometry exhibited during ground testing may significantly depart from the in-space configuration due to the presence of gravity-induced deformations (gravity sag) of lightly preloaded membranes. This paper describes a study carried (out to characterize gravity sag in two subscale gossamer structures: a single quadrant square solar sail and a single membrane layer from a multilayer sunshield. An experimental study was carried out to measure the global surface profiles using photogrammetry, and nonlinear finite element analysis was used to predict the behavior of the test articles. Comparison of measured and predicted surface profiles shows that the finite element analysis qualitatively predicts deformed shapes comparable to those observed in the laboratory. Quantitatively, finite element analysis predictions for peak gravity-induced deformations in both test articles were on the order of 10% of measured values. Results from this study provide increased insight into gravity sag behavior in gossamer structures, and demonstrates the potential to analytically predict gravity-induced deformations to within reasonable accuracy. C1 NASA, Goddard Space Flight Ctr, Mech Syst Anal & Simulat Branch, Greenbelt, MD 20771 USA. James Madison Univ, Harrisonburg, VA 22807 USA. Dartmouth Coll, Thayer Sch Engn, Hanover, NH 03755 USA. RP Johnston, JD (reprint author), NASA, Goddard Space Flight Ctr, Mech Syst Anal & Simulat Branch, Code 542, Greenbelt, MD 20771 USA. NR 21 TC 7 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 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JUL-AUG PY 2006 VL 43 IS 4 BP 762 EP 770 DI 10.2514/1.14298 PG 9 WC Engineering, Aerospace SC Engineering GA 071YY UT WOS:000239641000007 ER PT J AU Berry, SA Hamilton, H Wurster, KE AF Berry, Scott A. Hamilton, Harris, II Wurster, Kathryn E. TI Effect of computational method on discrete roughness correlations for Shuttle Orbiter SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA 32nd Fluid Dynamics Conference CY JUN 24-26, 2002 CL St Louis, MO SP Amer Inst Aeronaut & Astronaut ID BOUNDARY-LAYER-TRANSITION; AEROHEATING PREDICTIONS; X-34 AB A reanalysis of discrete roughness boundary-layer transition data using a consistent computational method for comparison to,other published results has been completed. The primary objective of this effort was to investigate the influence of the computational approach on the resulting transition correlation. The experimental results were previously obtained on Space Shuttle Orbiter models in the NASA Langley Research Center 20-Inch Mach 6 Air Tunnel. The phosphor thermography system was used to monitor the status of the boundary layer via global heat-transfer images of the orbiter windward surface. The existing roughness transition database included a variation in the size and location of discrete roughness trips along the centerline of 0.0075-scale models at an angle of attack of 40 deg. Various correlative approaches were attempted, with the roughness transition correlations based on edge properties providing the most reliable results. When a consistent computational method is used to compute edge conditions, transition data sets for different moderately blunt configurations at I several angles of Attack are shown to collapse to a well-behaved correlation. The shuttle experimental dataset presented herein, therefore, can be used to calibrate the preferred computational method of the end user for use in the future designs of the next-generation space access vehicles. C1 NASA, Langley Res Ctr, Aerothermodynam Branch, Res & Technol Directorate, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Vehicle Anal Branch, Syst Anal & Concepts Directorate, Hampton, VA 23681 USA. RP Berry, SA (reprint author), NASA, Langley Res Ctr, Aerothermodynam Branch, Res & Technol Directorate, Hampton, VA 23681 USA. NR 43 TC 6 Z9 6 U1 0 U2 0 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 JUL-AUG PY 2006 VL 43 IS 4 BP 842 EP 852 DI 10.2514/1.5182 PG 11 WC Engineering, Aerospace SC Engineering GA 071YY UT WOS:000239641000016 ER PT J AU Canabal, F Frendi, A AF Canabal, Francisco Frendi, Abdelkader TI Study of the ignition overpressure suppression technique by water addition SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB The main objective of this study is to gain an understanding of the mechanisms responsible for the suppression of the ignition overpressure observed when water-is injected through discrete nozzles into a rocket exhaust. A simplified launch-vehicle/launchpad configuration of relevant importance is selected for this study. This configuration is then numerically modeled using two-phase computational fluid dynamics with a representative motor startup sequence and a series of water addition configurations. The study focuses on the interaction between the ignition overpressure wave and the injected water., Chemical reactions are not included in the model; therefore, the effect of afterburning of fuel-rich exhaust is omitted in this study. A total of 11 water addition configurations were studied. The study demonstrated that ignition overpressure is strongly affected by the cooling, of the plume and the amount of obstruction restricting the expansion of the plume. Also, the study suggests the existence of an optimal water additional rate with a weak dependence on the water nozzle pressure drop. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Mech & Aerosp Dept, Huntsville, AL 35899 USA. RP Canabal, F (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 22 TC 5 Z9 5 U1 0 U2 1 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 JUL-AUG PY 2006 VL 43 IS 4 BP 853 EP 865 DI 10.2514/1.14861 PG 13 WC Engineering, Aerospace SC Engineering GA 071YY UT WOS:000239641000017 ER PT J AU Shelton, JD Frederick, RA Wilhite, AW AF Shelton, Joey D. Frederick, Robert A., Jr. Wilhite, Alan W. TI Launch vehicle propulsion design with multiple selection criteria SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB An analytical optimization and evaluation approach is presented for sizing a liquid hydrogen/liquid oxygen, single-stage-to-orbit system. The approach uses a unique merging of historical data for weight relationships, Monte Carlo simulations for uncertainty analysis, technology factors, thermochemical analysis, and genetic algorithm solvers for concept optimization. The. method models and optimizes engine chamber pressure, area ratio, and oxidizer/fuel ratio to determine the best vehicle design based on seven separate cost/weight figures of merit Model results show that a 53% increase in design, development, test, and evaluation cost results in a 67% reduction in gross liftoff weight. The uncertainty range for the design, development, test, and evaluation costs is shown to be from -45 to +76% of the mean value for the 95th percentile uncertainty case. The oxidizer/fuel ratio has a significant impact on the overall weight of the vehicle and vehicle components due to the large percentage of the gross liftoff weight that is dedicated to propellants. Other results show the effects of propulsion parameters, technology factors, and cost factors on weight and cost under different overall design constraints. C1 NASA, George C Marshall Space Flight Ctr, Space Transportat Programs & Projects Off, Huntsville, AL 35812 USA. Univ Alabama, Prop Res Ctr, Huntsville, AL 35899 USA. Georgia Inst Technol, Atlanta, GA USA. RP Shelton, JD (reprint author), NASA, George C Marshall Space Flight Ctr, Space Transportat Programs & Projects Off, NP20, Huntsville, AL 35812 USA. NR 5 TC 0 Z9 0 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 JUL-AUG PY 2006 VL 43 IS 4 BP 893 EP 902 DI 10.2514/1.16919 PG 10 WC Engineering, Aerospace SC Engineering GA 071YY UT WOS:000239641000021 ER PT J AU Pastor, JY LLorca, J Poza, P Quispe, JJ de Arellano Lopez, AR Martinez-Fernandez, J Sayir, A Orera, VM AF Pastor, JY LLorca, J Poza, P Quispe, JJ de Arellano Lopez, AR Martinez-Fernandez, J Sayir, A Orera, VM TI High-temperature tensile strength of Er2O3-doped ZrO2 single crystals SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID CRACK-GROWTH; DEGRADATION; ZIRCONIA AB The deformation and fracture mechanisms in tension were studied in single-crystal Er2O3-doped ZrO2 monofilaments processed by the laser-heated floating zone method. Tensile tests were carried out between 25 degrees and 1400 degrees C at different loading rates and the dominant deformation and fracture mechanisms were determined from the shape of the stress-strain curves, the morphology of the fracture surfaces, and the evidence provided by monofilaments deformed at high temperature and broken at ambient temperature. The tensile strength presented a minimum at 600 degrees-800 degrees C and it was controlled by the slow growth of a crack from the surface. This mechanism was also dominant in some monofilaments tested at 1000 degrees C and above, while others showed extensive plastic deformation before fracture at these temperatures. The strength of plastically deformed monofilaments was significantly higher than those which failed by slow crack growth due to the marked strain hardening capacity of this material. C1 Univ Politecn Madrid, Dept Mat Sci, ETS Ingn Caminos, E-28040 Madrid, Spain. Univ Rey Juan Carlos, Dept Ciencia & Ingn Mat, Escuela Super Ciencias Expt & Technol, Mostoles 28993, Spain. Univ Seville, Dept Condensed Matter Phys, Seville 41080, Spain. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Zaragoza, CSIC, Inst Ciencia Mat Aragon, E-50009 Zaragoza, Spain. RP LLorca, J (reprint author), Univ Politecn Madrid, Dept Mat Sci, ETS Ingn Caminos, E-28040 Madrid, Spain. EM jllorca@mater.upm.es RI LLorca, Javier/C-1140-2013; orera, Victor/A-4213-2011; MARTINEZ FERNANDEZ, JULIAN/K-1826-2012; Poza, Pedro/F-2428-2016; OI LLorca, Javier/0000-0002-3122-7879; MARTINEZ FERNANDEZ, JULIAN/0000-0002-1199-6638; Poza, Pedro/0000-0002-0496-4902; R. de Arellano Lopez, Antonio/0000-0002-7443-0244; Orera, Victor/0000-0001-9690-9064 NR 16 TC 1 Z9 1 U1 0 U2 9 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD JUL PY 2006 VL 89 IS 7 BP 2140 EP 2146 DI 10.1117/j.1551-2916.2006.00995.x PG 7 WC Materials Science, Ceramics SC Materials Science GA 055GT UT WOS:000238438900012 ER PT J AU Markley, FL AF Markley, F. Landis TI Attitude filtering on SO(3) SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article; Proceedings Paper CT AAS Malcolm D Shuster Astronautics Symposium CY JUN 13-15, 2005 CL Grand Isl, NY SP Amer Astronaut Soc ID SPACECRAFT ATTITUDE; VECTOR OBSERVATIONS; QUATERNION ESTIMATION; KALMAN FILTER; REPRESENTATIONS; CONSTRAINT; ALGORITHM AB A new method is presented for the simultaneous estimation of the attitude of a spacecraft and an N-vector of bias parameters. This method uses a probability distribution function defined on the Cartesian product of SO(3), the group of rotation matrices, and the Euclidean space R-N. The Fokker-Planck equation propagates the probability distribution function between measurements, and Bayes' formula incorporates measurement update information. This approach avoids all the issues of singular attitude representations or singular covariance matrices encountered in extended Kalman filters. In addition, the filter has a consistent initialization for a completely unknown initial attitude, owing to the fact that SO(3) is a compact space. C1 SUNY Buffalo, Buffalo, NY 14260 USA. NASA, Goddard Space Flight Ctr, Navigat & Control Syst Engn Branch, Greenbelt, MD 20771 USA. RP Markley, FL (reprint author), SUNY Buffalo, Buffalo, NY 14260 USA. EM landis.markley@nasa.gov NR 45 TC 9 Z9 9 U1 1 U2 4 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 JUL-DEC PY 2006 VL 54 IS 3-4 BP 391 EP 413 PG 23 WC Engineering, Aerospace SC Engineering GA 198CB UT WOS:000248603500011 ER PT J AU Cheng, Y Crassidis, JL Markley, FL AF Cheng, Yang Crassidis, John L. Markley, F. Landis TI Attitude estimation for large field-of-view sensors SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article; Proceedings Paper CT AAS Malcolm D Shuster Astronautics Symposium CY JUN 13-15, 2005 CL Grand Isl, NY SP Amer Astronaut Soc ID SPACECRAFT ATTITUDE AB The QUEST measurement noise model for unit vector observations has been widely used in spacecraft attitude estimation for more than twenty years. It was derived under the approximation that the noise lies in the tangent plane of the respective unit vector and is axially symmetrically distributed about the vector. For large field-of-view sensors, however, this approximation may be poor, especially when the measurement falls near the edge of the field of view. In this paper a new measurement noise model is derived based on a realistic noise distribution in the focal plane of a large field-of-view sensor, which shows significant differences from the QUEST model for unit vector observations far away from the sensor boresight. An extended Kalman filter for attitude estimation is then designed with the new measurement noise model. Simulation results show that with the new measurement model the extended Kalman filter achieves better estimation performance using large field-of-view sensor observations. C1 SUNY Buffalo, Buffalo, NY 14260 USA. SUNY Buffalo, Dept Mech & Aerosp Engn, Amherst, NY 14260 USA. NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Syst Engn Branch, Greenbelt, MD 20771 USA. RP Cheng, Y (reprint author), SUNY Buffalo, Buffalo, NY 14260 USA. EM cheng3@eng.buffalo.edu; johnc@eng.buffalo.edu; Landis.Markley@nasa.gov NR 18 TC 24 Z9 28 U1 1 U2 4 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 JUL-DEC PY 2006 VL 54 IS 3-4 BP 433 EP 448 PG 16 WC Engineering, Aerospace SC Engineering GA 198CB UT WOS:000248603500013 ER PT J AU Scheeres, DJ Hsiao, FY Park, RS Vilac, BF Maruskin, JM AF Scheeres, D. J. Hsiao, F.-Y. Park, R. S. Vilac, B. F. Maruskin, J. M. TI Fundamental limits on spacecraft orbit uncertainty and distribution propagation SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article; Proceedings Paper CT AAS Malcolm D Shuster Astronautics Symposium CY JUN 13-15, 2005 CL Grand Isl, NY SP Amer Astronaut Soc AB In this paper we present and review a number of fundamental constraints that exist on the propagation of orbit uncertainty and phase volume flows in astrodynarnics. These constraints arise due to the Hamiltonian nature of spacecraft dynamics. First we review the role of integral invariants and their connection to orbit uncertainty, and show how they can be used to formally solve the diffusion-less Fokker-Plank equation for a spacecraft probability density function. Then, we apply Gromov's Non-Squeezing Theorem, a recent advance in symplectic topology, to find a previously unrecognized fundamental constraint that exists on general, nonlinear mappings of orbit distributions. Specifically, for a given orbit distribution, it can be shown that the projection of future orbit uncertainties in each coordinate-momentum pair describing the system must be greater than or equal to a fundamental limit, called the symplectic width. This implies that there is always a fundamental limit to which we can know a spacecraft's future location in its coordinate and conjugate momentum space when mapped forward in time from an initial covariance distribution. This serves as an "uncertainty" principle for spacecraft uncertainty distributions. C1 SUNY Buffalo, Buffalo, NY 14260 USA. Univ Michigan, Dept Math, Ann Arbor, MI 48109 USA. Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. RP Scheeres, DJ (reprint author), SUNY Buffalo, Buffalo, NY 14260 USA. EM scheeres@umich.edu NR 17 TC 21 Z9 21 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 JUL-DEC PY 2006 VL 54 IS 3-4 BP 505 EP 523 PG 19 WC Engineering, Aerospace SC Engineering GA 198CB UT WOS:000248603500017 ER PT J AU Forbes, JM Wu, D AF Forbes, Jeffrey M. Wu, Dong TI Solar tides as revealed by measurements of mesosphere temperature by the MLS experiment on UARS SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID NONMIGRATING DIURNAL TIDES; GENERAL-CIRCULATION MODEL; STATIONARY PLANETARY-WAVES; LATENT-HEAT RELEASE; LOWER THERMOSPHERE WINDS; MIDDLE ATMOSPHERE; SEMIDIURNAL TIDES; TIDAL VARIABILITY; GLOBAL DISTRIBUTIONS; SEASONAL-VARIATION AB Temperatures between 25 and 86 km measured by the Microwave Limb Sounder (MLS) experiment on the Upper Atmosphere Research Satellite (UARS) are analyzed to delineate diurnal, semidiurnal, and terdiurnal tidal structures and stationary planetary waves. These Fourier components are determined from temperatures averaged in bins covering 5 latitude, 30 longitude and 1 h in local time. This study confirms the presence of diurnal nonmigrating tides with zonal wavenumbers s = 0, 2, - 3 [ s > 0 (s < 0) implying westward (eastward) propagation] and semidiurnal tides with s = 1 and 3, and some components of lesser importance that were previously determined from UARS wind measurements near 95 km. The seasonal latitudinal and height structures of these components are now revealed, and utilized to aid in interpreting their behaviors and ascertaining their origins. New discoveries include the terdiurnal s = 2 and s = 4 components, and trapped nonmigrating diurnal tides with s = 0 and s = 2. The former are likely to arise from nonlinear interaction between the migrating (s = 3) terdiurnal tide and the stationary planetary wave with s = 1. The latter may reflect the presence of a longitude-dependent in situ heat source, or in situ nonlinear interaction between the migrating diurnal tide and a stationary planetary wave with s = 1. The present results provide a rich mixture of observational results to challenge both mechanistic and general circulation models of the middle atmosphere. In addition, internal consistency is established between the MLS tidal temperatures at 86 km and previously derived tidal winds at 95 km within the context of tidal theory. This result represents one step in the validation of measurements required for successful application of data-model assimilation techniques to the mesosphere and lower thermosphere. C1 Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80305 USA. Jet Propuls Lab, Pasadena, CA USA. RP Forbes, JM (reprint author), Univ Colorado, Dept Aerosp Engn Sci, UCB 429, Boulder, CO 80305 USA. EM Forbes@colorado.edu RI Wu, Dong/D-5375-2012; OI FORBES, JEFFREY/0000-0001-6937-0796 NR 59 TC 72 Z9 75 U1 1 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUL PY 2006 VL 63 IS 7 BP 1776 EP 1797 DI 10.1175/JAS3724.1 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 067MT UT WOS:000239308000006 ER PT J AU Shiokawa, K Suzuki, S Otsuka, Y Ogawa, T Nakamura, T Mlynczak, MG Russell, JM AF Shiokawa, Kazuo Suzuki, Shin Otsuka, Yuichi Ogawa, Tadahiko Nakamura, Takuji Mlynczak, Martin G. Russell, James M., III TI A multi-instrument measurement of a mesospheric front-like structure at the equator SO JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN LA English DT Article ID OCTOBER 9; EVENT; ATMOSPHERE; CAMPAIGN; EMISSION; BORES; ALOHA; LIDAR AB We have made a comprehensive measurement of a front-like structure in the mesosphere at the equator at Kototabang, Indonesia (0.2 degrees S, 100.3 degrees E), using an airglow imager, an airglow temperature photometer, a meteor radar, and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite. The event was detected in airglow images of both OH-band (peak emission altitude: 87 km) and 557.7-nm (96-km) emissions, as an east-west front-like structure propagating northward with a velocity of 52-58 m/s. Wave trains with a horizontal wavelength of 30-70 km were observed after the passage of the front. The airglow intensity decreased for all the mesospheric emissions of OI (557.7 nm), OH-band, O-2-band (altitude: 94 km), and Na (589.3 nm) (90 km) after the front passage. The rotational temperatures of both the OH-band and the O-2-band also decreased similar to 10 K. An intense shear in northward wind velocity of 80 m/s/6 km was observed at altitudes of 84-90 km by the meteor radar. The kinetic temperature profile at altitudes of 20-120 km was observed near Kototabang by TIMED/SABER. The front-like structure and trailing waves were similar to those of the mesospheric tidal bore. However, we found that the ducting condition, which is necessary to form a bore, was not satisfied for the observed wave parameters. We speculate that the intense wind shear may play some role for the generation of the front-like structure. C1 Nagoya Univ, Solar Terrestrial Environm Lab, Toyokawa 4428507, Japan. Kyoto Univ, Res Inst Sustainalbe Humansosphere, Uji, Japan. NASA, Langley Res Ctr, Climate Sci Branch, Hampton, VA 23665 USA. RP Shiokawa, K (reprint author), Nagoya Univ, Solar Terrestrial Environm Lab, Toyokawa 4428507, Japan. EM shiokawa@stelab.nagoya-u.ac.jp RI Mlynczak, Martin/K-3396-2012 NR 16 TC 10 Z9 10 U1 0 U2 1 PU METEOROLOGICAL SOC JAPAN PI TOKYO PA C/O JAPAN METEOROLOGICAL AGENCY 1-3-4 OTE-MACHI, CHIYODA-KU, TOKYO, 100-0004, JAPAN SN 0026-1165 EI 2186-9057 J9 J METEOROL SOC JPN JI J. Meteorol. Soc. Jpn. PD JUL PY 2006 VL 84A BP 305 EP 316 DI 10.2151/jmsj.84A.305 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 077OR UT WOS:000240039800018 ER PT J AU Visser, TD Fischer, DG Wolf, E AF Visser, TD Fischer, DG Wolf, E TI Scattering of light from quasi-homogeneous sources by quasi-homogeneous media SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID TURBULENCE AB The field generated by scattering of light from a quasi-homogeneous source on a quasi-homogeneous, random medium is investigated. It is found that, within the accuracy of the first-order Born approximation, the far field satisfies two reciprocity relations (sometimes called uncertainty relations). One of them implies that the spectral density (or spectral intensity) is proportional to the convolution of the spectral density of the source and the spatial Fourier transform of the correlation coefficient of the scattering potential. The other implies that the spectral degree of coherence of the far field is proportional to the convolution of the correlation coefficient of the source and the spatial Fourier transform of the strength of the scattering potential. While the case we consider might seem restrictive, it is actually quite general. For instance, the quasi-homogeneous source model can be used to describe the generation of beams with different coherence properties and different angular spreads. In addition, the quasi-homogeneous scattering model adequately describes a wide class of turbulent media, including a stratified, turbulent atmosphere and confined plasmas. (C) 2006 Optical Society of America. C1 Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA. NASA, Micrograv Sci Div, Glenn Res Ctr, Cleveland, OH 44135 USA. Free Univ Amsterdam, Dept Phys & Astron, NL-1081 HV Amsterdam, Netherlands. Univ Rochester, Inst Opt, Rochester, NY 14627 USA. Univ Cent Florida, CREOL, Coll Opt, Orlando, FL 32816 USA. RP Visser, TD (reprint author), Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA. EM tvisser@nat.vu.nl NR 12 TC 67 Z9 70 U1 3 U2 8 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1084-7529 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD JUL PY 2006 VL 23 IS 7 BP 1631 EP 1638 DI 10.1364/JOSAA.23.001631 PG 8 WC Optics SC Optics GA 057WW UT WOS:000238626900011 PM 16783426 ER PT J AU Yerkes, KL Michalak, TE Baysinger, KM Puterbaugh, R Thomas, SK McQuillen, J AF Yerkes, Kirk L. Michalak, Travis E. Baysinger, Kerri M. Puterbaugh, Rebekah Thomas, Scott K. McQuillen, John TI Variable-gravity effects on a single-phase partially confined spray cooling system SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article AB The testing of a single-phase spray cooling system that was flown on the NASA KC-135 Reduced-Gravity Research Aircraft is discussed. An experimental package, consisting of a spray chamber coupled to a fluid delivery loop system, was fabricated for variable gravity flight tests. The spray chamber contains two opposing nozzles spraying on indium tin oxide (ITO) heaters. These heaters are mounted on glass posts that are part of a sump system to remove unconstrained liquid from the test chamber. Thermocouples mounted in and around, the posts were used to determine both the heat loss through the underside of the ITO heater and the heat extracted by the spray. During flight tests, for Weber numbers,We = 771 +/- 19 and 757 +/- 15, the nondimensional, heat input was varied from G Delta = 25 to 110 for the nondimensional grouping ((FrGa)-Ga-1/2)(1/2) = 20-66. Flight-test data and terrestrial data were compared to analytical and numerical solutions to evaluate the heat transfer in the heater and support structure. In general, the Nusselt number at the heater surface was found to decrease with increasing ((FrGa)-Ga-1/2)(1/2). C1 USAF, Res Lab, PRPS, Wright Patterson AFB, OH 45433 USA. Wright State Univ, Dept Mech & Mat Engn, Dayton, OH 45435 USA. NASA, John H Glenn Res Ctr Lewis Field, Micrograv Fluid Phys Branch, Cleveland, OH 44135 USA. RP Yerkes, KL (reprint author), USAF, Res Lab, PRPS, 1950 5th St, Wright Patterson AFB, OH 45433 USA. NR 10 TC 10 Z9 10 U1 3 U2 3 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 JUL-SEP PY 2006 VL 20 IS 3 BP 361 EP 370 DI 10.2514/1.18681 PG 10 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 068ZL UT WOS:000239414000002 ER PT J AU Chao, DF Sankovic, JA Zhang, N AF Chao, David F. Sankovic, John A. Zhang, Nengli TI Profile patterns and stability of evaporating liquid sessile drops SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article ID MINUTE DROPS; CONTACT LINE; CONVECTION; SURFACE C1 NASA, John H Glenn Res Ctr Lewis Field, Micrograv Div, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Dept Workforce Enhancement, Cleveland, OH 44142 USA. RP Chao, DF (reprint author), NASA, John H Glenn Res Ctr Lewis Field, Micrograv Div, Mail Stop 77-5, Cleveland, OH 44135 USA. EM n.zhang@grc.nasa.gov NR 17 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 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JUL-SEP PY 2006 VL 20 IS 3 BP 620 EP 624 DI 10.2514/1.16141 PG 5 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 068ZL UT WOS:000239414000035 ER PT J AU Bronikowski, MJ Manohara, HM Hunt, BD AF Bronikowski, Michael J. Manohara, Harish M. Hunt, Brian D. TI Growth of carbon nanotube bundle arrays on silicon surfaces SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A LA English DT Article; Proceedings Paper CT 52nd International Symposium of the American-Vacuum-Society CY OCT 30-NOV 04, 2005 CL Boston, MA SP Amer Vacuum Soc ID FIELD-EMISSION; EMITTERS; IRON AB The growth on silicon substrates of arrayed bundles of multiwalled carbon nanotubes (CNTs) by metal catalyzed chemical vapor deposition of carbon from ethylene has been characterized and optimized. We find that, while CNTs can grow on bare Si substrates, the growth is substantially more reproducible if a thin (similar to 3 nm) barrier layer of aluminum oxide is used between the Si surface and iron catalyst. Optimum Fe thickness and growth temperature are 3.0 nm and 650 degrees C, respectively. We find that the CNT length increases linearly with time at a rate of 3-4 mu m/min for up to 2 h of CNT growth, after which the growth ceases. The length of the resulting CNT can thus be controlled up to a maximum length of similar to 500 mu m. Such control over CNT bundle length will be crucial in the incorporation of these bundle arrays into high-intensity electron field emission devices. (c) 2006 American Vacuum Society. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bronikowski, MJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM michael.j.bronikowski@jpl.nasa.gov NR 11 TC 12 Z9 12 U1 1 U2 7 PU A V S AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A PD JUL-AUG PY 2006 VL 24 IS 4 BP 1318 EP 1322 DI 10.1116/1.2172943 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 063VN UT WOS:000239048100075 ER PT J AU Allen, CA Franz, DE Moseley, SH AF Allen, C. A. Franz, D. E. Moseley, S. H. TI Compliant system of polyimide microwires for cryogenic detector applications SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A LA English DT Article; Proceedings Paper CT 52nd International Symposium of the American-Vacuum-Society CY OCT 30-NOV 04, 2005 CL Boston, MA SP Amer Vacuum Soc AB We have developed a system of highly compliant, low thermal conductance electrical interconnects c for cryogenic detector applications. The arrays of microwires are metallic, thin-film electrical leads supported by a layer of polyimide, capable of spanning the thermally isolated gap between the detector array and the low temperature heat sink in cryogenic detector assemblies. The low thermal conductance of the microwires enables detector thermal isolation without the need for conventional hard wiring, such as soldered manganin (an alloy of nickel, manganese, aluminum, iron, and copper) or stainless steel. Designed for compactness, an array of 30 microwires can be designed to fit on a silicon chip less than one-half of I cm 2 in total surface area. We describe techniques for fabrication of arrays of polyimide microwires with several different types of conductive traces, both superconducting and normal metals. Mechanical elongation of 20% beyond the design length resulted in an increase in aluminum microwire resistance of only 1%, and no stress to the polyimide. Cryogenic elongation yielded no change in electrical or mechanical properties. The thermal conductivity of a single, aluminum microwire is found to be 3.8 X 10(-8) W / K at 4.4 K and 1.1 X 10(-8) W/K at 2.2 K. C1 NASA, Goddard Space Flight Ctr, Detector Syst Branch, Greenbelt, MD 21029 USA. NASA, Goddard Space Flight Ctr, Observ Cosmol Lab, Greenbelt, MD 21029 USA. RP Allen, CA (reprint author), NASA, Goddard Space Flight Ctr, Detector Syst Branch, Greenbelt, MD 21029 USA. EM christine.allen@nasa.gov NR 4 TC 3 Z9 3 U1 0 U2 2 PU A V S AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A PD JUL-AUG PY 2006 VL 24 IS 4 BP 1552 EP 1555 DI 10.1116/1.2194922 PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 063VN UT WOS:000239048100118 ER PT J AU Mattson, MC Mullin, KD Ingram, GW Hoggard, W AF Mattson, MC Mullin, KD Ingram, GW Hoggard, W TI Age structure and growth of the bottlenose dolphin (Tursiops truncatus) from strandings in the Mississippi sound region of the north-central Gulf of Mexico from 1986 to 2003 SO MARINE MAMMAL SCIENCE LA English DT Article DE bottlenose dolphin; Tursiops truncatus; age; growth; Laird-Gompertz growth model; Gulf of Mexico ID PACIFIC-OCEAN; REPRODUCTION; ABUNDANCE; CETACEANS; PATTERNS; WATERS AB Despite their high abundance and wide distribution, little is known about the historical or current growth and age structure of coastal bottlenose dolphins (Tursiops truncatus) in the north-central Gulf of Mexico. Between 1986 and 2003, teeth were collected from bottlenose dolphins stranded on the mainland coast of Mississippi and the adjacent barrier islands. Bottlenose dolphin strandings occurred year round, peaking in March and April. Neonate strandings also peaked during these 2 mo. Age estimates were obtained from 111 animals by reading the growth layer groups in the dentine layer of the teeth. The ages ranged from < 1 yr to 30 yr of age. The two-stage Laird-Gompertz growth model was fitted to the total length and age data. On the basis of this model, the asymptotic lengths were estimated at 250 cm for females and 255 cm for males. The length at birth estimates were 98-103 cm for females and 100-107 cm for males. These lengths are similar to those of bottlenose dolphin populations from other Gulf of Mexico areas and from the North Atlantic Ocean along the southeastern United States. C1 NOAA, SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, Pascagoula, MS 39567 USA. RP Mattson, MC (reprint author), NOAA, SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, 3209 Frederic St, Pascagoula, MS 39567 USA. EM keith.d.mullin@noaa.gov NR 31 TC 23 Z9 27 U1 2 U2 10 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 2006 VL 22 IS 3 BP 654 EP 666 DI 10.1111/j.1748-7692.2006.00057.x PG 13 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 051UK UT WOS:000238186500009 ER PT J AU Guggilla, P Batra, AK Currie, JR Aggarwal, MD Alim, MA Lal, RB AF Guggilla, P Batra, AK Currie, JR Aggarwal, MD Alim, MA Lal, RB TI Pyroelectric ceramics for infrared detection applications SO MATERIALS LETTERS LA English DT Article DE pyroelectric; infrared sensor; PZT ceramics ID IMMITTANCE DATA; PLZT CERAMICS; CRYSTALS; DEVICES; FILMS AB Pyroelectric and dielectric behavior of cation(s) modified lead zirconate titanate (PZT) ceramic has been studied for their use in infrared detectors. Various materials' figures-of-merit for their use in infrared detector are calculated. The results are compared with several existing candidate materials including PZT type ceramics. (c) 2006 Elsevier B.V. All rights reserved. C1 Alabama A&M Univ, Dept Phys, Normal, AL 35762 USA. NASA Marshall Space Flight Ctr, Avion Dept, Huntsville, AL 35812 USA. Alabama A&M Univ, Dept Elect Engn, Normal, AL 35762 USA. RP Batra, AK (reprint author), Alabama A&M Univ, Dept Phys, POB 1268, Normal, AL 35762 USA. EM ashok.batra@email.aamu.edu NR 25 TC 29 Z9 31 U1 3 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-577X J9 MATER LETT JI Mater. Lett. PD JUL PY 2006 VL 60 IS 16 BP 1937 EP 1942 DI 10.1016/j.matlet.2005.05.086 PG 6 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 045QK UT WOS:000237756600001 ER PT J AU Sephton, MA James, RH Zolensky, ME AF Sephton, Mark A. James, Rachael H. Zolensky, Michael E. TI The origin of dark inclusions in Allende: New evidence from lithium isotopes SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID LI; LI-7/LI-6; CHONDRITE; VIGARANO; RECORD AB Aqueous and thermal processing of primordial materials occurred prior to and during planet formation in the early solar system. A record of how solid materials were altered at this time is present in the carbonaceous chondrites, which are naturally delivered fragments of primitive asteroids. It has been proposed that some materials, such as the clasts termed "dark inclusions" found in type III chondrites, suggest a sequence of aqueous and thermal events. Lithium isotopes (Li-6 and Li-7) can reveal the role of liquid water in dark inclusion history. During aqueous alteration, Li-7 passes preferentially into solution leaving Li-6 behind in the solid phase and, consequently, any relatively extended periods of interaction with Li-7-rich fluids would have left the dark inclusions enriched in the heavier isotope when compared to the meteorite as a whole. Our analyses of lithium isotopes in Allende and its dark inclusions reveal marked isotopic homogeneity and no evidence of greater levels of aqueous alteration in dark inclusion history. C1 Univ London Imperial Coll Sci & Technol, IARC, Dept Earth Sci & Engn, London SW7 2AZ, England. Open Univ, Dept Earth Sci, Milton Keynes MK7 6AA, Bucks, England. KT NASA Johnson Space Ctr, Houston, TX 77058 USA. RP Sephton, MA (reprint author), Univ London Imperial Coll Sci & Technol, IARC, Dept Earth Sci & Engn, S Kensington Campus, London SW7 2AZ, England. EM m.a.sephton@imperial.ac.uk RI James, Rachael/G-8613-2011 NR 24 TC 13 Z9 13 U1 1 U2 4 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2006 VL 41 IS 7 BP 1039 EP 1043 PG 5 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 068CL UT WOS:000239349400005 ER PT J AU Nettles, JW Lofgren, GE Carlson, WD McSween, HY AF Nettles, Jeffrey W. Lofgren, Gary E. Carlson, William D. McSween, Harry Y., Jr. TI Extent of chondrule melting: Evaluation of experimental textures, nominal grain size, and convolution index SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID DYNAMIC CRYSTALLIZATION; CHONDRITES AB Dynamic crystallization experiments on the ordinary chondrite Queen Alexandra Range (QUE) 97008 document textural features that occur in partially melted chondrules with changes in the degree of partial melting and cooling rate. We carried out a matrix of experiments, at peak temperatures of 1250, 1350, 1370, and 1450 degrees C, and cooling rates of 1000, 100, and 10 degrees C/h, and quenched. All experimentally produced textures closely resemble textures of porphyritic chondrules. Because peak temperatures were well below the liquidi for typical chondrule compositions, the textural similarities support an incomplete melting origin for most porphyritic chondrules. Our experiments can be used to determine the extent of melting of natural chondrules by comparing textural relationships among the experimental results with those of natural chondrules. We used our experiments along with X-ray computerized tomography scans of a Semarkona chondrule to evaluate two other methods that have been used previously to quantify the degree of melting: nominal grain size and convolution index. Proper applications of these methods can result in valid assessments of a chondrule's degree of melting, but only if accompanied by careful interpretation, as chondrule textures are controlled by more than just the extent of melting. Such measurements of single aspects of chondrule textures might be coupled with qualitative analysis of other textural aspects to accurately determine degree of melting. C1 Univ Tennessee, Dept Earth & Planetary Sci, Knoxville, TN 37996 USA. NASA Johnson Space Ctr, Astromat Acquisit & Curat, Houston, TX 77058 USA. Univ Texas, Dept Geol Sci, Austin, TX 78712 USA. Univ Tennessee, Dept Earth & Planetary Sci, Knoxville, TN 37996 USA. RP Nettles, JW (reprint author), Univ Tennessee, Dept Earth & Planetary Sci, Knoxville, TN 37996 USA. EM jnettle1@utk.edu RI Carlson, William/A-5807-2008 OI Carlson, William/0000-0002-2954-5886 NR 23 TC 5 Z9 5 U1 1 U2 2 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2006 VL 41 IS 7 BP 1059 EP 1071 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 068CL UT WOS:000239349400007 ER PT J AU Martins, Z Watson, JS Sephton, MA Botta, O Ehrenfreund, P Gilmour, I AF Martins, Z. Watson, J. S. Sephton, M. A. Botta, O. Ehrenfreund, P. Gilmour, I. TI Free dicarboxylic and aromatic acids in the carbonaceous chondrites Murchison and Orgueil SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID MONOCARBOXYLIC ACIDS; ULTRAVIOLET PHOTOLYSIS; ORGANIC-MATTER; ACETIC-ACID; METEORITE; HYDROCARBONS; ANTARCTICA AB We have analyzed an important fraction of the free carboxylic acids present in water extracts of the CM2 chondrite Murchison and the Cl I chondrite Orgueil using gas chromatography-mass spectrometry (GC-MS). The free nature of the carboxylic acids analyzed was ensured by employing a single-step water extraction. Analyses revealed the presence of a structurally diverse suite of both aliphatic and aromatic acids in Murchison, while Orgueil exhibits a simpler distribution of exclusively aromatic acids. Within the Murchison aromatic acids, there are previously unreported phthalic acids, methyl phthalic acids, and hydroxybenzoic acids. In Orgueil, benzoic acid and very small amounts of methylbenzoic acids and methylhydroxybenzoic acids were detected. For the aromatic acids in both Murchison and Orgueil, most structural isomers were identified, suggesting an origin by abiotic processes. Quantitative differences are evident between acids in the two meteorites; carboxylic. acids are much more abundant in Murchison than in Orgueil. The data suggest that differing levels of aqueous alteration on the meteorite parent body(ies) has produced dissimilar distributions of carboxylic acids. C1 Leiden Inst Chem, Astrobiol Lab, NL-2300 RA Leiden, Netherlands. Open Univ, Planetary & Space Sci Res Inst, Milton Keynes MK7 6AA, Bucks, England. Imperial Coll, Dept Earth Sci & Engn, Impacts & Astromat Res Ctr, London SW7 2AZ, England. NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Martins, Z (reprint author), Leiden Inst Chem, Astrobiol Lab, NL-2300 RA Leiden, Netherlands. EM z.martins@chem.leidenuniv.nl RI Martins, Zita/H-4860-2015; OI Martins, Zita/0000-0002-5420-1081; Gilmour, Iain/0000-0002-2860-9489; Watson, Jonathan/0000-0003-0354-1729 NR 24 TC 23 Z9 23 U1 4 U2 13 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2006 VL 41 IS 7 BP 1073 EP 1080 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 068CL UT WOS:000239349400008 ER PT J AU Priddey, RS Tanvir, NR Levan, AJ Fruchter, AS Kouveliotou, C Smith, IA Wijers, RAMJ AF Priddey, R. S. Tanvir, N. R. Levan, A. J. Fruchter, A. S. Kouveliotou, C. Smith, I. A. Wijers, R. A. M. J. TI Millimetric properties of gamma-ray burst host galaxies SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE dust, extinction; galaxies : evolution; cosmology : observations; gamma-rays : bursts; infrared : galaxies; submillimetre ID SCUBA SUBMILLIMETER OBSERVATIONS; STAR-FORMATION; NUMBER COUNTS; LUMINOSITY; REDSHIFT; DUST; DISTRIBUTIONS; ULTRAVIOLET; GRB-020124; STARBURST AB We present millimetre (mm) and submillimetre (submm) photometry of a sample of five host galaxies of gamma-ray bursts (GRBs), obtained using the Max Planck Millimetre Bolometer (MAMBO2) array and Submillimetre Common-User Bolometer Array (SCUBA). These observations were obtained as part of an ongoing project to investigate the status of GRBs as indicators of star formation. Our targets include two of the most unusual GRB host galaxies, selected as likely candidate submm galaxies: the extremely red (R - K approximate to 5) host of GRB 030115, and the extremely faint (R > 29.5) host of GRB 020124. Neither of these galaxies is detected, but the deep upper limits for GRB 030115 impose constraints on its spectral energy distribution, requiring a warmer dust temperature than is commonly adopted for submillimetre galaxies (SMGs). As a framework for interpreting these data, and for predicting the results of forthcoming submm surveys of Swift-derived host samples, we model the expected flux and redshift distributions based on luminosity functions of both submm galaxies and GRBs, assuming a direct proportionality between the GRB rate density and the global star formation rate density. We derive the effects of possible sources of uncertainty in these assumptions, including (1) introducing an anticorrelation between GRB rate and the global average metallicity, and (2) varying the dust temperature. C1 Univ Hertfordshire, Ctr Astrophys Res, Hatfield AL10 9AB, Herts, England. Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Marshall Space Flight Ctr, NSSTC, Huntsville, AL 35805 USA. Rice Univ, Dept Phys & Astron, Houston, TX 77056 USA. Univ Amsterdam, Fac Sci, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. RP Priddey, RS (reprint author), Univ Hertfordshire, Ctr Astrophys Res, Coll Lane, Hatfield AL10 9AB, Herts, England. EM priddey@star.herts.ac.uk OI Wijers, Ralph/0000-0002-3101-1808 NR 36 TC 22 Z9 22 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 JUL 1 PY 2006 VL 369 IS 3 BP 1189 EP 1195 DI 10.1111/j.1365-2966.2006.10355.x PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 054CM UT WOS:000238353800014 ER PT J AU Kang, JH Park, C Gaik, SJ Lowther, SE Harrison, JS AF Kang, Jin Ho Park, Cheol Gaik, Steven J. Lowther, Sharon E. Harrison, Joycelyn S. TI The effect of single wall carbon nanotubes on the dipole orientation and piezoelectric properties of polymeric nanocomposites SO NANO LA English DT Article DE piezoelectricity; single wall carbon nanotube (SWNT); thermally stimulated current (TSC); dipole orientation; interfacial polarization AB Recently, a series of single wall carbon nanotube (SWNT) polyimide nanocomposites were developed since the demand of electroactive polymeric materials as sensors and actuators for use in high temperature applications has been growing. Adding SWNTs into electroactive polyimides enhanced their electrostrictive strain as well as their mechanical integrities and chemical stability. Although an increase in piezoelectricity resulting from the incorporation of SWNTs could be expected, there has been no systematic study detailing the effect of SWNTs on piezoelectricity. In this article, the effects of various types and concentrations of SWNT on the dipole orientation and piezoelectricity were investigated using a thermally stimulated current (TSC) technique and a modified Rheovibron. It was found that the barely modified SWNTs led to a more substantial increase in the remanent polarization (P-r) than the highly modified SWNTs did. As the loading level of SWNTs increased, P-r increased. However, excessive loading of SWNTs showed a reduction in P-r since the actual poling field decreased due to a large leakage of current. The trend of the piezoelectric strain coefficient, d(31), was consistent with that of P-r. The increase in interfacial polarization caused by adding SWNT was believed to be primarily responsible for the increase of P-r and d(31). C1 [Kang, Jin Ho; Park, Cheol] NASA, Langley Res Ctr, Natl Inst Aerosp, Hampton, VA 23681 USA. [Gaik, Steven J.] Penn State Univ, Dept Chem Engn, University Pk, PA 16802 USA. [Lowther, Sharon E.; Harrison, Joycelyn S.] NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. RP Park, C (reprint author), NASA, Langley Res Ctr, Natl Inst Aerosp, MS 226, Hampton, VA 23681 USA. EM j.h.kang@larc.nasa.gov; c.park@larc.nasa.gov; sjg212@psu.edu; s.e.lowther@larc.nasa.gov; j.s.harrison@larc.nasa.gov NR 23 TC 13 Z9 13 U1 1 U2 6 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 1793-2920 J9 NANO JI Nano PD JUL PY 2006 VL 1 IS 1 BP 77 EP 85 DI 10.1142/S1793292006000100 PG 9 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Science & Technology - Other Topics; Materials Science; Physics GA V44JH UT WOS:000202998500009 ER PT J AU Chesley, SR Ward, SN AF Chesley, SR Ward, SN TI A quantitative assessment of the human and economic hazard from impact-generated tsunami SO NATURAL HAZARDS LA English DT Article DE asteroid; impact; tsunami AB In this article, we assess the human and economic hazard posed by tsunami waves generated from impacts of sub-2 km diameter asteroids. Annually, on average, 182(+197/-123) people will be affected by impact-induced waves with a corresponding infrastructure loss of $18(+20/-12)M/y. Half of the tsunami hazard stems from impactors with diameters less than 300 m. One near Earth asteroid will survive atmospheric transit and strike somewhere into Earth's oceans every 5880 years, on average. In the mean generic scenario, the tsunami from the impact affects 1.1 million people and destroys $110B of infrastructure. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Santa Cruz, Inst Geophys & Planetary Phys, Santa Cruz, CA 95064 USA. RP Chesley, SR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM steve.chesley@jpl.nasa.gov NR 21 TC 16 Z9 16 U1 0 U2 5 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0921-030X J9 NAT HAZARDS JI Nat. Hazards PD JUL PY 2006 VL 38 IS 3 BP 355 EP 374 DI 10.1007/s11069-005-1921-y PG 20 WC Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences; Water Resources SC Geology; Meteorology & Atmospheric Sciences; Water Resources GA 039VG UT WOS:000237335000004 ER PT J AU Valle-Levinson, A Blanco, JL Frangopulos, M AF Valle-Levinson, A Blanco, JL Frangopulos, M TI Hydrography and frontogenesis in a glacial fjord off the Strait of Magellan SO OCEAN DYNAMICS LA English DT Article; Proceedings Paper CT 12th International Biennial Conference on Physics of Estuaries and Coastal Seas CY OCT 19-22, 2004 CL Merida, MEXICO ID TIDAL INTRUSION FRONT; RIVER PLUME; FLOW; CONVERGENCE; ESTUARIES; CURRENTS; INLET AB Current velocity and hydrographic profiles obtained for the first time in a Chilean glacial fjord were combined with under-way surface temperature and salinity measurements to describe the formation of tidal intrusion fronts and plume-like fronts. These fronts formed within several hundred meters from each other in the vicinity of a shallow sill, maximum depth of approximately 3 m, in a glacial fjord off the Strait of Magellan in the Chilean Patagonia. Measurements were obtained in mid-December of 2003 and 2004, during late austral spring, under active glacier melting and calving. The glacial fjord is approximately 18 km long from the face of the glacier to the connection with the Strait of Magellan and typically less than 1 km wide throughout the system. Between the glacier face and the 3-m sill, depths are typically less than 100 m, and seaward of the sill, depths increase to more than 200 m. Velocity and salinity data obtained during flood periods revealed that water with oceanic salinity was aspirated to near-surface levels from depths of approximately 30 m as flood flows accelerated from approximately 10 cm s(-1), seaward of the sill, to approximately 60 cm s(-1) at the sill crest. The upwelled water was then slightly diluted by mixing at the sill crest before plunging down to the basin between the glacier and the sill. The plunging of salty water over the sill created dramatic tidal intrusion fronts only a few tens of meters from the sill crest and pumping of salt with every flood period. During ebb periods, the low salinity waters derived from the glacier and a small river near the glacier converged at the sill crest. After some mixing, the buoyant waters were released within a thin layer (similar to 3 m deep) lead by a plume-like front that remained coherent for a few hundred meters seaward of the sill. The main findings of this study were that tidal intrusion and plume fronts were observed within 2 km from each other, and that tidal pumping was the predominant mechanism for salt fluxes into the system. C1 Univ Florida, Civil & Coastal Engn Dept, Gainesville, FL 32611 USA. NASA, Wallops Flight Facil, Observ Sci Branch, Wallops Isl, VA 23337 USA. Ctr Estudios Cuaternario Fuego Patagonia CEQUA, Inst Fomento Pesquero, Punta Arenas, Chile. RP Valle-Levinson, A (reprint author), Univ Florida, Civil & Coastal Engn Dept, 365 Weil Hall, Gainesville, FL 32611 USA. EM arnoldo@ufl.edu NR 17 TC 12 Z9 15 U1 0 U2 4 PU SPRINGER HEIDELBERG PI HEIDELBERG PA TIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANY SN 1616-7341 J9 OCEAN DYNAM JI Ocean Dyn. PD JUL PY 2006 VL 56 IS 3-4 BP 217 EP 227 DI 10.1007/s10236-005-0048-8 PG 11 WC Oceanography SC Oceanography GA 056OE UT WOS:000238533200003 ER PT J AU Rocchio, L AF Rocchio, L TI Fighting crop insurance fraud with Landsat SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. RP Rocchio, L (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. EM lroccio@ltpmail.gsfa.nasa.gov NR 0 TC 2 Z9 2 U1 0 U2 1 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 USA SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD JUL PY 2006 VL 72 IS 7 BP 725 EP 727 PG 3 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 058ZZ UT WOS:000238704400001 ER PT J AU Su, HP Karna, D Fraim, E Fitzgerald, M Dominguez, R Myers, JS Coffland, B Handley, LR Mace, T AF Su, HP Karna, D Fraim, E Fitzgerald, M Dominguez, R Myers, JS Coffland, B Handley, LR Mace, T TI Evaluation of eelgrass beds mapping using a high-resolution airborne multispectral scanner SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID LAND-USE; ACCURACY; BAY; MAP AB Eelgrass (Zostera marina) can provide vital ecological functions in stabilizing sediments, influencing current dynamics, and contributing significant amounts of biomass to numerous food webs in coastal ecosystems. Mapping eelgrass beds is important for coastal water and nearshore estuarine monitoring, management, and planning. This study demonstrated the possible use of high spatial (approximately 5 m) and temporal (maximum low tide) resolution airborne multispectral scanner on mapping eelgrass beds in Northern Puget Sound, Washington. A combination of supervised and unsupervised classification approaches were performed on the multispectral scanner imagery. A normalized difference vegetation index (NDVI) derived from the red and near-infrared bands and ancillary spatial information, were used to extract and mask eelgrass beds and other submerged aquatic vegetation (SAV) in the study area. We evaluated the resulting thematic map (geocoded, classified image) against a conventional aerial photograph interpretation using 260 point locations randomly stratified over five defined classes from the thematic map. We achieved an overall accuracy of 92 percent with 0.92 Kappa Coefficient in the study area. This study demonstrates that the airborne multispectral scanner can be useful for mapping eelgrass beds in a local or regional scale, especially in regions for which optical remote sensing from space is constrained by climatic and tidal conditions. C1 Univ Calif Santa Cruz, NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. USGS, Natl Wetlands Res Ctr, Lafayette, LA 70506 USA. NASA, Dryden Flight Res Ctr, Edwards AFB, CA 93523 USA. RP Su, HP (reprint author), Univ Calif Santa Cruz, NASA, Ames Res Ctr, MS-240-6,Bldg 240,Room 219, Moffett Field, CA 94035 USA. EM hsu@mail.arc.nasa.gov NR 28 TC 7 Z9 7 U1 1 U2 7 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 USA SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD JUL PY 2006 VL 72 IS 7 BP 789 EP 797 PG 9 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 058ZZ UT WOS:000238704400009 ER PT J AU Lakew, B Aslam, S Jones, H Moeckly, B Brasunas, J Franz, D AF Lakew, B Aslam, S Jones, H Moeckly, B Brasunas, J Franz, D TI Effect of ionizing radiation on noise in MgB2 thin film - a candidate material for detector development for post-Cassini planetary missions SO PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS LA English DT Article DE umagnesium diboride; MgB2; bolometer; noise spectral density; ionizing radiation; superconductor ID REACTIVE EVAPORATION; BOLOMETER AB A thin film of MgB2 grown oil a SiN-Si substrate, with a superconducting transition temperature, T-c, near 39 K has been irradiated with gamma-rays from a Co-60 source. The total dose was 100 Krads (Si). Its pre- and post-irradiation noise has been measured and noise spectral density plots made. No change in dR/d T, pre- and post-irradiation was measured. At the mid-point of the transition, T = 38.24 K, a noise spectral density S-V = 0.34 nV Hz(-1/2) was measured at 10 Hz. The temperature noise, K-n, of the MgB2 film at different frequencies is compared to that of high temperature superconducting (HTS) thin films (YBaCuO and GdBaCuO with T-c similar to 90 K) used currently in HTS transit ion-edge bolometers. Even with the observed post-irradiation small increase in noise, its lower T-c and K-n values predict that high performance far IR bolometers call be developed using MgB2 as a thermistor. (c) 2006 Elsevier B.V. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. MEI Technol, Lanham, MD 20706 USA. Supercond Technol Inc, Santa Barbara, CA 93111 USA. RP Lakew, B (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM brook.lakew@nasa.gov RI Aslam, Shahid/D-1099-2012; brasunas, john/I-2798-2013 NR 15 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD JUL 1 PY 2006 VL 440 IS 1-2 BP 1 EP 5 DI 10.1016/j.physc.2006.03.043 PG 5 WC Physics, Applied SC Physics GA 056AE UT WOS:000238492100001 ER PT J AU Mizumoto, Y Kayanuma, Y Srivastava, A Kono, J Chin, AH AF Mizumoto, Yoshihiko Kayanuma, Yosuke Srivastava, Ajit Kono, Junichiro Chin, Alan H. TI Dressed-band theory for semiconductors in a high-intensity infrared laser field SO PHYSICAL REVIEW B LA English DT Article ID ELECTRIC-FIELD; SUPERLATTICES; SPECTRA; STATES; TIME AB Under the illumination of intense off-resonant laser light, the electronic states of semiconductors are strongly modified, or dressed, by the oscillating electric field. We present a framework using linear combination of atomic orbital band theory to calculate the dressed band structure and optical absorption spectrum of covalent semiconductors in an intense off-resonant laser field. The interaction with the laser field is taken into account exactly from the beginning of the band calculation. It is shown that the irradiation of an intense infrared laser gives rise to a blueshift of the absorption edge as well as the emergence of a new absorption band below the edge, in agreement with recent experimental data for GaAs crystals. C1 Osaka Prefecture Univ, Grad Sch Engn, Sakai, Osaka 5998531, Japan. Rice Univ, Dept Elect & Comp Engn, Houston, TX 77005 USA. NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Mizumoto, Y (reprint author), Osaka Prefecture Univ, Grad Sch Engn, 1-1 Gakuencho, Sakai, Osaka 5998531, Japan. NR 28 TC 20 Z9 20 U1 3 U2 6 PU AMER 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 JUL PY 2006 VL 74 IS 4 AR 045216 DI 10.1103/PhysRevB.74.045216 PG 11 WC Physics, Condensed Matter SC Physics GA 069DR UT WOS:000239426800061 ER PT J AU Howard, A Sukhatme, GS Mataric, MJ AF Howard, Andrew Sukhatme, Gaurav S. Mataric, Maja J. TI Multirobot simultaneous localization and mapping using manifold representations SO PROCEEDINGS OF THE IEEE LA English DT Article DE exploration and search; multirobot systems; simultaneous localization and mapping (SLAM) ID MOBILE ROBOTS AB This paper describes a novel representation for two-dimensional maps, and shows how this representation may be applied to the problem of multirobot simultaneous localization and mapping. We are inspired by the notion of a manifold, which takes maps out of the two-dimensional plane and onto a surface embedded in A higher-dimensional space. The key advantage of the manifold representation is self-consistency: when closing loops, manifold maps do not suffer from the "cross over" problem exhibited in planar maps. This self-consistency, in turn, facilitates a number of important capabilities, including autonomous exploration, search, and retro-traverse. it also supports a very robust form of loop closure, in which pairs of robots act collectively to confirm or reject possible correspondence points. in this paper, we develop the basic formalism of the manifold representation, show how this may be applied to the multirobot simultaneous localization and mapping problem, and present experimental results obtained from teams of up to four robots in environments ranging in size from 400 to 900 m(2). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ So Calif, Dept Comp Sci, Los Angeles, CA 90089 USA. RP Howard, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM abhoward@robotics.jpl.nasa.gov; gaurav@cs.usc.edu; mataric@cs.usc.edu NR 19 TC 45 Z9 46 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9219 J9 P IEEE JI Proc. IEEE PD JUL PY 2006 VL 94 IS 7 BP 1360 EP 1369 DI 10.1109/JPROC.2006.876922 PG 10 WC Engineering, Electrical & Electronic SC Engineering GA 077MK UT WOS:000240033300009 ER PT J AU Georgiadis, NJ DeBonis, JR AF Georgiadis, Nicholas J. DeBonis, James R. TI Navier-Stokes analysis methods for turbulent jet flows with application to aircraft exhaust nozzles SO PROGRESS IN AEROSPACE SCIENCES LA English DT Review DE jet; turbulence; nozzle; LES; RANS ID LARGE-EDDY SIMULATION; NONREFLECTING BOUNDARY-CONDITIONS; FINITE-DIFFERENCE SCHEMES; REYNOLDS-NUMBER JET; RUNGE-KUTTA SCHEMES; COMPUTATIONAL ACOUSTICS; COMPRESSIBLE TURBULENCE; COMPLEX GEOMETRIES; AERODYNAMIC SOUND; LOW-DISSIPATION AB This article presents the current status of computational fluid dynamics (CFD) methods as applied to the simulation of turbulent jet flowfields issuing from aircraft engine exhaust nozzles. For many years, Reynolds-averaged Navier-Stokes (RANS) methods have been used routinely to calculate such flows, including very complex nozzle configurations. RANS methods replace all turbulent fluid dynamic effects with a turbulence model. Such turbulence models have limitations for jets with significant three-dimensionality, compressibility, and high temperature streams. In contrast to the RANS approach, direct numerical simulation (DNS) methods calculate the entire turbulent energy spectrum by resolving all turbulent motion down to the Kolmogorov scale. Although this avoids the limitations associated with turbulence modeling, DNS methods will remain computationally impractical in the foreseeable future for all but the simplest configurations. Large-Eddy simulation (LES) methods, which directly calculate the large-scale turbulent structures and reserve modeling only for the smallest scales, have been pursued in recent years and may offer the best prospects for improving the fidelity of turbulent jet flow simulations. A related approach is the group of hybrid RANS/LES methods, where RANS is used to model the small-scale turbulence in wall boundary layers and LES is utilized in regions dominated by the large-scale jet mixing. The advantages, limitations, and applicability of each approach are discussed and recommendations for further research are presented. (c) 2007 Elsevier Ltd. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Georgiadis, NJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM Georgiadis@nasa.gov NR 134 TC 20 Z9 20 U1 4 U2 23 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0376-0421 J9 PROG AEROSP SCI JI Prog. Aeosp. Sci. PD JUL-AUG PY 2006 VL 42 IS 5-6 BP 377 EP 418 DI 10.1016/j.paerosci.2006.12.001 PG 42 WC Engineering, Aerospace SC Engineering GA 169NB UT WOS:000246597800001 ER PT J AU Gaspari, G Cohn, SE Guo, J Pawson, S AF Gaspari, Gregory Cohn, Stephen E. Guo, Jing Pawson, Steven TI Construction and application of covariance functions with variable length-fields SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE correlation functions; correlation length-scale; data assimilation; non-separable; Quasi-Biennial Oscillation ID QUASI-BIENNIAL OSCILLATION; VARIATIONAL ASSIMILATION 3D-VAR; RANGE FORECAST ERRORS; ECMWF IMPLEMENTATION; STATISTICAL STRUCTURE; RADIOSONDE DATA; ANALYSIS SYSTEM; KALMAN FILTER; FORMULATION; MODEL AB This article focuses on construction, directly in physical space, of three-dimensional covariance functions parametrized by a length-field, and on an application of these functions to improve the representation of the Quasi-Biennial Oscillation (QBO) in the Goddard Earth Observing System, Version 4 (GEOS-4) data assimilation system. The covariance functions are obtained by fusing collections of auto-covariance functions having different constant length-scales with their associated cross-covariance functions. This construction yields covariance functions with length-scales that can vary arbitrarily over any finite partition of the spatial domain. A simple, and also motivating application of these functions is to the case where the length-scale varies in the vertical direction only. The class of covariance functions with variable length-fields constructed in this article will be called multi-level to associate them with this application. The multi-level covariance functions extend well-known single-level covariance functions depending only on a constant length-scale. Generalizations of the familiar first- and third-order autoregressive covariances in three dimensions are given, providing multi-level covariances with zero and four continuous derivatives at zero separation, respectively. Multi-level piecewise rational covariances with two continuous derivatives at zero separation are also provided. Multi-level power-law covariances are constructed with continuous derivatives of all orders. Additional multi-level covariance functions are constructed using the Schur product of single- and multi-level covariance functions. A multi-variate, multi-level power-law covariance with a large troposphere-to-stratosphere length-field gradient is employed to reproduce the QBO from sparse radiosonde wind observations in the tropical lower stratosphere. This covariance model is described along with details of the assimilation experiments. The new covariance model is shown to represent the vertical wind shear associated with the QBO much more effectively than the multi-variate, multi-level covariance model in the baseline GEOS-4 system. C1 SAIC, Adv Syst & Concepts Div, Arlington, VA 22203 USA. Sci Applicat Int Corp, Beltsville, MD USA. NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. RP Gaspari, G (reprint author), SAIC, Adv Syst & Concepts Div, 4001 N Fairfax Dr,Suite 725, Arlington, VA 22203 USA. EM gasparig@saic.com RI Cohn, Stephen/K-1954-2012; Pawson, Steven/I-1865-2014 OI Cohn, Stephen/0000-0001-8506-9354; Pawson, Steven/0000-0003-0200-717X NR 29 TC 29 Z9 29 U1 0 U2 5 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING RG1 7LJ, BERKS, ENGLAND SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD JUL PY 2006 VL 132 IS 619 BP 1815 EP 1838 DI 10.1256/qj.05.08 PN B PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 098TM UT WOS:000241545700003 ER PT J AU Alford, JM Mason, GR Feikema, DA AF Alford, J. M. Mason, G. R. Feikema, D. A. TI Free fall plasma-arc reactor for synthesis of carbon nanotubes in microgravity SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID LASER VAPORIZATION; SINGLE; MECHANISM; DISCHARGE; DIAMETER; FLAMES; GROWTH AB High temperatures inside the plasma of a carbon arc generate strong buoyancy driven convection which has an effect on the growth and morphology of the single-walled carbon nanotubes (SWNTs). To study the effect of buoyancy on the arc process, a miniature carbon arc apparatus was designed and developed to synthesize SWNTs in a microgravity environment substantially free from buoyant convective flows. An arc reactor was operated in the 2.2 and 5.18 s drop towers at the NASA Glenn Research Center. The apparatus employed a 4 mm diameter anode and was powered by a portable battery pack capable of providing in excess of 300 A at 30 V to the arc for the duration of a 5 s drop. However, the principal result is that no dramatic difference in sample yield or composition was noted between normal gravity and 2.2 and 5 s long microgravity runs. Much longer duration microgravity time is required for SWNT's growth such as the zero-G aircraft, but more likely will need to be performed on the international space station or an orbiting spacecraft. (c) 2006 American Institute of Physics. C1 TDA Res Inc, Wheat Ridge, CO 80228 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Feikema, DA (reprint author), TDA Res Inc, 12345 W 52nd Ave, Wheat Ridge, CO 80228 USA. EM jma@tda.com; gmason@tda.com; douglas.feikema@grc.nasa.gov NR 39 TC 3 Z9 3 U1 1 U2 7 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0034-6748 EI 1089-7623 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUL PY 2006 VL 77 IS 7 AR 074101 DI 10.1063/1.2209972 PG 11 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 069DC UT WOS:000239424800027 ER PT J AU Rabii, B Winant, CD Collins, JS Lee, AT Richards, PL Abroe, ME Hanany, S Johnson, BR Ade, P Balbi, A Bock, JJ Borrill, J Stompor, R Boscaleri, A Pascale, E de Bernardis, P Ferreira, PG Hristov, VV Lange, AE Jaffe, AH Netterfield, CB Smoot, GF Wu, JHP AF Rabii, B. Winant, C. D. Collins, J. S. Lee, A. T. Richards, P. L. Abroe, M. E. Hanany, S. Johnson, B. R. Ade, P. Balbi, A. Bock, J. J. Borrill, J. Stompor, R. Boscaleri, A. Pascale, E. de Bernardis, P. Ferreira, P. G. Hristov, V. V. Lange, A. E. Jaffe, A. H. Netterfield, C. B. Smoot, G. F. Wu, J. H. P. TI MAXIMA: A balloon-borne cosmic microwave background anisotropy experiment SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID COSMOLOGICAL PARAMETERS; RADIATION; MAPS; CONTAMINATION; TRANSMISSION; FOREGROUNDS; BOLOMETER; BOOMERANG; EMISSION; TESTS AB We describe the Millimeter wave Anisotropy eXperiment IMaging Array (MAXIMA), a balloon-borne experiment which measured the temperature anisotropy of the cosmic microwave background (CMB) on angular scales of 10(') to 5 degrees. MAXIMA mapped the CMB using 16 bolometric detectors in spectral bands centered at 150, 240, and 410 GHz, with 10(') resolution at all frequencies. The combined receiver sensitivity to CMB anisotropy was similar to 40 mu K root s. The bolometric detectors, which were cooled to 100 mK, were a prototype of the detectors which will be used on the Planck Surveyor Satellite of the European Space Agency. Systematic parasitic contributions were controlled by using four uncorrelated spatial modulations, thorough cross-linking, multiple independent CMB observations, heavily baffled optics, and strong spectral discrimination. Pointing reconstruction was accurate to 1('), and absolute calibration was better than 4%. Two MAXIMA flights with more than 8.5 h of CMB observations have mapped a total of 300 deg(2) of the sky in regions of negligible known foreground emission. MAXIMA results have been released in previous publications and shown to be consistent with the Wilkinson Microwave Anisotropy Probe. MAXIMA I maps, power spectra, and correlation matrices are publicly available at http://cosmology.berkeley.edu/maxima. (c) 2006 American Institute of Physics. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Phys, Berkeley, CA 94720 USA. Univ Minnesota, Sch Phys & Astron, St Paul, MN 55455 USA. Cardiff Univ, Dept Phys, Cardiff CF24 3YB, Wales. Univ Roma Tor Vergata, I-00133 Rome, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Pasadena, CA 91125 USA. Lawrence Berkeley Natl Lab, Computat Res Div, Berkeley, CA 94720 USA. CNR, IFAC, I-50127 Florence, Italy. Univ Oxford, Oxford OX1 3RH, England. Univ London Imperial Coll Sci & Technol, London SW7 2BW, England. Univ Toronto, Dept Phys, Toronto, ON M5S 3H8, Canada. Natl Taiwan Univ, Dept Phys, Taipei 106, Taiwan. RP Rabii, B (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. EM bahman@physics.berkeley.edu; cwinant@bolo.berkeley.edu RI Jaffe, Andrew/D-3526-2009; OI WU, JIUN-HUEI/0000-0001-9608-7662; de Bernardis, Paolo/0000-0001-6547-6446 NR 51 TC 7 Z9 7 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUL PY 2006 VL 77 IS 7 AR 071101 DI 10.1063/1.2219723 PG 25 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 069DC UT WOS:000239424800001 ER PT J AU Landel, RF AF Landel, Robert F. TI A two-part tale: The WLF equation and beyond linear viscoelasticity SO RUBBER CHEMISTRY AND TECHNOLOGY LA English DT Review ID STYRENE-BUTADIENE RUBBER; STORED ENERGY FUNCTION; CROSSLINK DENSITY; ELASTOMERS; DEFORMATION; TEMPERATURE; BEHAVIOR; SBR; RELAXATION; DEPENDENCE C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. Arefel Consulting, Santa Cruz, CA 95065 USA. RP Landel, RF (reprint author), CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. EM rflandel@cruzio.com NR 37 TC 1 Z9 1 U1 3 U2 6 PU AMER CHEMICAL SOC INC PI AKRON PA RUBBER DIV UNIV AKRON PO BOX 499, AKRON, OH 44309-0499 USA SN 0035-9475 J9 RUBBER CHEM TECHNOL JI Rubber Chem. Technol. PD JUL-AUG PY 2006 VL 79 IS 3 BP 381 EP + DI 10.5254/1.3547943 PG 23 WC Polymer Science SC Polymer Science GA 214IZ UT WOS:000249732500001 ER PT J AU Foster, J Kelly, R Rango, A Armstrong, R Erbe, EF Pooley, C Wergin, WP AF Foster, James Kelly, Richard Rango, Albert Armstrong, Richard Erbe, Eric F. Pooley, Christopher Wergin, William P. TI Use of low-temperature scanning electron microscopy to compare and characterize three classes of snow cover SO SCANNING LA English DT Article DE snow crystal; snow cover; depth hoar; low-temperature scanning electron microscopy ID WATER EQUIVALENT; ICE CRYSTALS; MICROWAVE; AREA; METAMORPHISM; SUBLIMATION; SYSTEM; GROWTH AB This study, which uses low-temperature scanning electron microscopy (LTSEM), systematically sampled and characterized snow crystals that were collected from three unique classes of snow cover: prairie, taiga, and alpine. These classes, which were defined in previous field studies, result from exposure to unique climatic variables relating to wind, precipitation, and air temperature. Snow samples were taken at 10 cm depth intervals from the walls of freshly excavated snow pits. The depth of the snow pits for the prairie, taiga, and alpine covers were 28, 81, and 110 cm, respectively. Visual examination revealed that the prairie snow cover consisted of two distinct layers whereas the taiga and alpine covers had four distinct layers. Visual measurements were able to establish the range of crystal sizes that occurred in each layer, the temperature within the pit, and the snow density. The LTSEM observations revealed the detailed structures of the types of crystals that occurred in the snow covers, and documented the metamorphosis that transpired in the descending layers. Briefly, the top layers from two of the snow covers consisted of freshly fallen snow crystals that could be readily distinguished as plates and columns (prairie) or graupel (taiga). Alternatively, the top layer in the alpine cover consisted of older dendritic crystal fragments that had undergone early metamorphosis, that is, they had lost their sharp edges and had begun to show signs of joining or bonding with neighboring crystals. A unique layer, known as sun crust, was found in the prairie snow cover; however, successive samplings from all three snow covers showed similar stages of metamorphism that led to the formation of depth hoar crystals. These changes included the gradual development of large, three-dimensional crystals having clearly defined flat faces, sharp edges, internal depressions, and facets. The study, which indicates that LTSEM can be used to enhance visual data by systematically characterizing snow crystals that are collected at remote locations, is important for understanding the physics of snowpacks and the metamorphosis that leads to potential avalanche situations. In addition, the metamorphosis of snow crystals must be considered when microwave radiometry is used to estimate the snow water equivalent in the winter snowpack, because large snow crystals more effectively scatter passive microwave radiation than small crystals. C1 ARS, Soybean Genom Improvement Lab, USDA, Beltsville, MD 20705 USA. ARS, Hydrol & Remote Sensing Lab, USDA, Beltsville, MD 20705 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher & Biospher Sci, Greenbelt, MD 20771 USA. Univ Waterloo, Dept Geog, Waterloo, ON N2L 3G1, Canada. New Mexico State Univ, ARS, USDA, Jornada Expt Range, Las Cruces, NM 88003 USA. Univ Colorado, Natl Snow & Ice Data Ctr, Boulder, CO 80309 USA. RP Wergin, WP (reprint author), ARS, Soybean Genom Improvement Lab, USDA, Beltsville, MD 20705 USA. EM wwergin@msn.com NR 43 TC 3 Z9 3 U1 0 U2 4 PU FAMS INC PI MAHWAH PA BOX 832, MAHWAH, NJ 07430-0832 USA SN 0161-0457 J9 SCANNING JI Scanning PD JUL-AUG PY 2006 VL 28 IS 4 BP 191 EP 203 PG 13 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA 076JC UT WOS:000239952200001 PM 16898666 ER PT J AU Morgan, H Habbal, SR Woo, R AF Morgan, Huw Habbal, Shadia Rifai Woo, Richard TI The depiction of coronal structure in white-light images SO SOLAR PHYSICS LA English DT Article ID SOLAR CORONA; WIND; PHOTOMETRY; STREAMERS; DENSITY; ECLIPSE AB The very steep decrease in density with heliocentric distance makes imaging of coronal density structures out to a few solar radii challenging. The radial gradient in brightness can be reduced using numerous image processing techniques, thus quantitative data are manipulated to provide qualitative images. We introduce a new normalizing-radial-graded filter (NRGF): a simple filter for removing the radial gradient to reveal coronal structure. Applied to polarized brightness observations of the corona, the NRGF produces images which are striking in their detail. Total-brightness, white-light images include contributions from the F corona, stray light, and other instrumental contributions which need to be removed as effectively as possible to properly reveal the electron corona structure. A new procedure for subtracting this background from LASCO C2 white-light, total-brightness images is introduced. The background is created from the unpolarized component of total-brightness images and is found to be remarkably time-invariant, remaining virtually unchanged over the solar cycle. By direct comparison with polarized-brightness data, we show that the new background-subtracting procedure is superior in depicting coronal structure accurately, particularly when used in conjunction with the NRGF. The effectiveness of the procedures is demonstrated on a series of LASCO C2 observations of a coronal mass ejection (CME). C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Morgan, H (reprint author), Univ Hawaii, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. EM hmorgan@ifa.hawaii.edu OI Morgan, Huw/0000-0002-6547-5838 NR 19 TC 57 Z9 60 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 JUL PY 2006 VL 236 IS 2 BP 263 EP 272 DI 10.1007/s11207-006-0113-6 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 065FW UT WOS:000239146100003 ER PT J AU Chen, TB Sutton, AK Haugerud, BM Henderson, W Prakash, APG Cressler, JD Doolittle, A Liu, XF Joseph, A Marshall, PW AF Chen, Tianbing Sutton, Akil K. Haugerud, Becca M. Henderson, Walter Prakash, A. P. Gnana Cressler, John D. Doolittle, Alan Liu, Xuefeng Joseph, Alvin Marshall, Paul W. TI An investigation of the effects of radiation exposure on stability constraints in epitaxial SiGe strained layers SO SOLID-STATE ELECTRONICS LA English DT Article DE SiGe; SiGeHBT; thin film; epitaxy; stability; XRD; radiation ID RELAXATION; SILICON AB The thermodynamic stability of device-relevant epitaxial SiGe strained layers under proton irradiation is investigated using X-ray diffraction techniques, and compared with its stability constrain under high-temperature annealing. Irradiation with 63 MeV protons is found to introduce no significant microdefects into the SiGe thin films, regardless of starting stability condition of the SiGe film, and thus does not appear to be an issue for the use of SiGe HBT technology in emerging space systems. The strain relaxation of SiGe thin film under thermal annealing, however, is sensitive to the composition and thickness of the as-grown samples, as expected, with the subsequent lattice relaxation of the unstable samples occurring at a much higher rate than that of metastable samples. (c) 2006 Elsevier Ltd. All rights reserved. C1 Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA. Natl Semicond Corp, Santa Clara, CA 95052 USA. IBM Corp, Essex Jct, VT 05452 USA. NASA, GSFC, Greenbelt, MD 20771 USA. RP Chen, TB (reprint author), Georgia Inst Technol, Sch Elect & Comp Engn, 777 Atlantic Dr NW, Atlanta, GA 30332 USA. EM tianbing@ece.gatech.edu RI A P, Gnana Prakash/G-8054-2012 NR 16 TC 2 Z9 2 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-1101 J9 SOLID STATE ELECTRON JI Solid-State Electron. PD JUL-AUG PY 2006 VL 50 IS 7-8 BP 1194 EP 1200 DI 10.1016/j.sse.2006.05.018 PG 7 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 086IY UT WOS:000240668200006 ER PT J AU Dass, A Mulik, S Sotiriou-Leventis, C Leventis, N AF Dass, Amala Mulik, Sudir Sotiriou-Leventis, Chariklia Leventis, Nicholas TI Protection of 2-(3-thienyl)ethanol with 3-thienylacetic acid and hard cross-linked conducting films by electropolymerization of the ester SO SYNTHETIC METALS LA English DT Article DE electropolymerization; cross-linked; ester; 2-(3-thienyl)ethanol ID POLYMER-COVERED ELECTRODES; OLIGOTHIOPHENE CATION RADICALS; REACTIVE GROUPS; COATED ELECTRODES; AQUEOUS-SOLUTIONS; METHYLENE BLUE; PI-DIMERS; MONOSUBSTITUTED BITHIOPHENES; OXIDATIVE POLYMERIZATION; SELF-ASSOCIATION AB The ester (compound 1) of 2-(3-thienyl)ethanol (T-etOH) with 3-thienylacetic acid was synthesized as a monomer whose two thiophene groups could be electropolymerized independently, becoming members of different polymer chains in a highly cross-linked highly insoluble polymer. Indeed, 1 was electropolymerized successfully alone and together with 3-methylthiophene (3MeT). Films of poly(l) are hard (3H, as opposed to < 6B for poly(3MeT)), and the close proximity of the polymeric strands creates pi-stacking interactions. The behavior of 1 suggests that by: (a) limiting the potential used for the oxidation of monomeric esters of T-etOH at the foot of their oxidation waves (< 1.8 V versus Ag/AgCl) and (b) compensating for the decrease in the electrogenerated radical concentration by increasing the monomer concentration, practically all esters of T-etOH should be electropolymerizable. This was confirmed by durable film formation from the archetypical ester of T-etOH, the 2-(3-thienyl)ethyl acetate (T-etOAc), whose homoelectropolymerization is reported for the first time. (c) 2006 Published by Elsevier B.V. C1 Univ Missouri, Dept Chem, Rolla, MO 65409 USA. NASA, Glenn Res Ctr, Div Mat, Cleveland, OH 44135 USA. RP Sotiriou-Leventis, C (reprint author), Univ Missouri, Dept Chem, Rolla, MO 65409 USA. EM cslevent@umr.edu; Nicholas.Leventis@nasa.gov RI Dass, Amala/H-4729-2012 OI Dass, Amala/0000-0001-6942-5451 NR 45 TC 7 Z9 7 U1 1 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUL 1 PY 2006 VL 156 IS 14-15 BP 966 EP 972 DI 10.1016/j.synthmet.2006.06.015 PG 7 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 087UE UT WOS:000240767100014 ER PT J AU Huang, JL Gogarten, JP AF Huang, Jinling Gogarten, Johann Peter TI Ancient horizontal gene transfer can benefit phylogenetic reconstruction SO TRENDS IN GENETICS LA English DT Review ID TRANSFER-RNA SYNTHETASES; RED ALGAE; EVOLUTIONARY PROCESS; NUCLEAR GENES; GENOME; EUKARYOTES; ORIGIN; PLANTS; PLASTIDS; REVEALS AB Although horizontal gene transfer (HGT) is usually considered a disruptive force in recovering organismal phylogeny, it creates important phylogenetic information. In the 'net of life', the recipient of an ancient gene transfer can be the ancestor of a lineage that inherits the transferred gene; thus, the transferred gene marks the recipient and its descendants as a monophyletic group. Ancient gene transfer events can also reveal the order of emergence of donor and recipient lineages. In addition, these ancient events can significantly shape the genetic systems of the recipients and can play a part in their long-term evolution. In this article, we discuss the recent progress in phylogenetic application of ancient HGTs and describe two examples of transfer events to the ancestor of red algae and green plants that support a common origin of these two groups. We also address the potential pitfalls of this application. C1 E Carolina Univ, Dept Biol, Greenville, NC 27858 USA. Univ Connecticut, Dept Mol & Cell Biol, Storrs, CT 06269 USA. NASA, Astrobiol Inst, Biol Marine Lab, Woods Hole, MA 02543 USA. RP Huang, JL (reprint author), E Carolina Univ, Dept Biol, Greenville, NC 27858 USA. EM huangj@ecu.edu OI Gogarten, Johann Peter/0000-0001-6459-6518 NR 58 TC 48 Z9 52 U1 1 U2 13 PU ELSEVIER SCIENCE LONDON PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0168-9525 J9 TRENDS GENET JI Trends Genet. PD JUL PY 2006 VL 22 IS 7 BP 361 EP 366 DI 10.1016/j.tig.2006.05.004 PG 6 WC Genetics & Heredity SC Genetics & Heredity GA 072PE UT WOS:000239684500005 PM 16730850 ER PT J AU DellaCorte, C AF DellaCorte, Christopher TI Cover to cover - the only way to read TLT! SO TRIBOLOGY & LUBRICATION TECHNOLOGY LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Cleveland, OH USA. RP DellaCorte, C (reprint author), NASA, Glenn Res Ctr, Cleveland, OH USA. EM cdellacorte@stle.org NR 0 TC 1 Z9 1 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 0024-7154 J9 TRIBOL LUBR TECHNOL JI Tribol. Lubr. Technol. PD JUL PY 2006 VL 62 IS 7 BP 6 EP 6 PG 1 WC Engineering, Mechanical SC Engineering GA 061KB UT WOS:000238869800002 ER PT J AU Dibb, JE Scheuer, E Avery, M Plant, J Sachse, G AF Dibb, Jack E. Scheuer, Eric Avery, Melody Plant, Jim Sachse, Glen TI In situ evidence for renitrification in the Arctic lower stratosphere during the polar aura validation experiment (PAVE) SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID REACTIVE NITROGEN; TROPOSPHERE EXPERIMENT; AIRCRAFT MEASUREMENTS; AASE-II; WINTER; HNO3; NOY; OZONE; DC-8; O-3 AB In-situ measurements of nitric acid (HNO3), ozone (O-3), and nitrous oxide (N2O) were made from the NASA DC-8 during the Polar Aura Validation Experiment in January/February 2005. In the lower stratosphere (9-12.5 km, potential temperature 300 - 350 K) characteristic compact relationships were observed between all three gases. The ratio HNO3/O-3 averaged 3.5 ( +/- 0.7) ppt/ppb. Samples with enhanced HNO3/O-3 (> 4.0) were most abundant under the edge of the Arctic Polar vortex in airmasses with enhanced mixing ratios of both gases (> 400 ppb O-3 and > 2000 ppt HNO3) and reduced mixing ratios of N2O (< 305 ppb), indicating air from higher levels in the stratosphere. Relationships to N2O in the anomalous samples under the vortex edge indicate that increases in HNO3/O-3 reflect renitrification at DC-8 flight levels, with no indication of significant O-3 loss. Renitrified air was only observed at potential temperatures above 340 K, and was most abundant on the PAVE flights on 27 and 29 January. C1 Univ New Hampshire, Inst Study Earth Oceans & Space, Climate Change Res Ctr, Durham, NH 03824 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Dibb, JE (reprint author), Univ New Hampshire, Inst Study Earth Oceans & Space, Climate Change Res Ctr, Morse Hall,39 Coll Rd, Durham, NH 03824 USA. EM jack.dibb@unh.edu NR 15 TC 16 Z9 16 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 JUN 30 PY 2006 VL 33 IS 12 AR L12815 DI 10.1029/2006GL026243 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 062IK UT WOS:000238937600004 ER PT J AU Newman, PA Nash, ER Kawa, SR Montzka, SA Schauffler, SM AF Newman, Paul A. Nash, Eric R. Kawa, S. Randolph Montzka, Stephen A. Schauffler, Sue M. TI When will the Antarctic ozone hole recover? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STRATOSPHERIC AIR; ART.; DEPLETION; TRENDS; TEMPERATURE; CHEMISTRY; CHLORINE; MODELS; VORTEX AB The Antarctic ozone hole demonstrates large-scale, man-made affects on our atmosphere. Surface observations now show that human produced ozone-depleting substances (ODSs) are declining. The ozone hole should soon start to diminish because of this decline. We demonstrate a parametric model of ozone hole area that is based upon a new algorithm for estimating chlorine and bromine levels over Antarctica and late spring Antarctic stratospheric temperatures. This model explains 95% of the ozone hole area's variance. We then use future ODS levels to predict ozone hole recovery. Full recovery to 1980 levels will occur around 2068 and the area will very slowly decline between 2001 and 2017. Detection of a statistically significant decrease of area will not occur until about 2024. We further show that nominal Antarctic stratospheric greenhouse gas forced temperature change should have a small impact on the ozone hole. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Natl Ctr Atmospher Res, Boulder, CO 80305 USA. RP Newman, PA (reprint author), NASA, Goddard Space Flight Ctr, Code 613-3,8800 Greenbelt Rd, Greenbelt, MD 20771 USA. EM paul.a.newman@nasa.gov RI Newman, Paul/D-6208-2012; Kawa, Stephan/E-9040-2012; OI Newman, Paul/0000-0003-1139-2508; Montzka, Stephen/0000-0002-9396-0400 NR 21 TC 101 Z9 102 U1 2 U2 19 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 JUN 30 PY 2006 VL 33 IS 12 AR L12814 DI 10.1029/2005GL025232 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 062IK UT WOS:000238937600001 ER PT J AU Pulkkinen, A Kataoka, R AF Pulkkinen, Antti Kataoka, Ryuho TI S-transform view of geomagnetically induced currents during geomagnetic superstorms SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOLAR-WIND; FIELD; FLUCTUATIONS; SYSTEMS AB A novel time-frequency analysis method (S-transform) capable of handling noisy non-stationary signals is applied to study the properties of geomagnetically induced current (GIC) fluctuations in the Finnish natural gas pipeline. New local time- and storm phase-dependent S-transform spectral properties of auroral region GIC fluctuations during geomagnetic superstorms are reported. More specifically, the S-transform spectra have two distinct regions containing the most of the spectral power that persisted from storm to storm: main phase-related wide-band fluctuations driven possibly by a substorm-type ionospheric activity centered around the local midnight and recovery phase-related narrow-band fluctuations associated with Pc5 range geomagnetic pulsations in the local morning region. Based on this observed "stability'', a new S-transform-based statistical approach using, for example, an ensemble of different S-transform responses for known storms is proposed for GIC prediction. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Inst Informat & Commun Technol, Tokyo, Japan. Nagoya Univ, Solar Terr Environm Lab, Chikusa Ku, Nagoya, Aichi 4648601, Japan. RP Pulkkinen, A (reprint author), NASA, Goddard Space Flight Ctr, Code 612-2, Greenbelt, MD 20771 USA. EM antti.pulkkinen@gsfc.nasa.gov; ryuho@stelab.nagoya.u.ac.jp NR 18 TC 11 Z9 11 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 JUN 30 PY 2006 VL 33 IS 12 AR L12108 DI 10.1029/2006GL025822 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 062IK UT WOS:000238937600003 ER PT J AU Dessler, AE Palm, SP Spinhirne, JD AF Dessler, A. E. Palm, S. P. Spinhirne, J. D. TI Tropical cloud-top height distributions revealed by the Ice, Cloud, and Land Elevation Satellite (ICESat)/Geoscience Laser Altimeter System (GLAS) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPOPAUSE LAYER; DIURNAL CYCLE; DEEP CONVECTION; WATER-VAPOR; SAGE-II; CIRRUS; TRANSPORT; STRATOSPHERE; DEHYDRATION; FREQUENCY AB [1] We analyze cloud-top height data obtained at tropical latitudes between 29 September and 17 November, 2003, from the Geoscience Laser Altimeter System (GLAS), carried onboard the Ice, Cloud, and Land Elevation Satellite (ICESat). About 66% of the tropical observations show one or more cloud layers. Of those observations that do show a cloud, about half show two or more cloud layers. Maxima in the cloud-top height distribution occur in the upper troposphere, between 12 and 17 km, and in the lower troposphere, below about 4 km. A less prominent maximum occurs in the midtroposphere, between 6 and 8 km. The occurrence of cloud layers tends to be consistent with the well-known diurnal cycles of continental and oceanic convection, and we find that cloud layers tend to occur more frequently over land than ocean, except in the lower troposphere, where the opposite is true. A particular emphasis of this paper is the convection that penetrates into the so-called tropical tropopause layer (TTL). We find more frequent occurrence of thick clouds in the TTL and above the tropopause than other studies, with 3.0% and 19% of the thick and thin cloud observations, respectively, showing a cloud top in the TTL and 0.34% and 3.1% showing a cloud top above the average level of the tropopause. These values are higher than those found in other data sets and suggest that an upward revision of TTL cloud frequency might be necessary. TTL clouds are observed more frequently in the evening than in the morning and more frequently over land than over ocean. C1 Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Dessler, AE (reprint author), Texas A&M Univ, Dept Atmospher Sci, TAMU 3150, College Stn, TX 77843 USA. EM adessler@tamu.edu RI Dessler, Andrew/G-8852-2012 OI Dessler, Andrew/0000-0003-3939-4820 NR 49 TC 46 Z9 46 U1 0 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 JUN 30 PY 2006 VL 111 IS D12 AR D12215 DI 10.1029/2005JD006705 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 062IX UT WOS:000238938900005 ER PT J AU Palmer, PI Suntharalingam, P Jones, DBA Jacob, DJ Streets, DG Fu, QY Vay, SA Sachse, GW AF Palmer, Paul I. Suntharalingam, Parvadha Jones, Dylan B. A. Jacob, Daniel J. Streets, David G. Fu, Qingyan Vay, Stephanie A. Sachse, Glen W. TI Using CO2 : CO correlations to improve inverse analyses of carbon fluxes SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC CO2; SATELLITE-OBSERVATIONS; AIRCRAFT OBSERVATIONS; CHEMICAL EVOLUTION; TRANSPORT PATHWAYS; ASIAN OUTFLOW; ART.; EMISSION; PACIFIC; MONOXIDE AB [1] Observed correlations between atmospheric concentrations of CO2 and CO represent potentially powerful information for improving CO2 surface flux estimates through coupled CO2-CO inverse analyses. We explore the value of these correlations in improving estimates of regional CO2 fluxes in east Asia by using aircraft observations of CO2 and CO from the TRACE-P campaign over the NW Pacific in March 2001. Our inverse model uses regional CO2 and CO surface fluxes as the state vector, separating biospheric and combustion contributions to CO2. CO2-CO error correlation coefficients are included in the inversion as off-diagonal entries in the a priori and observation error covariance matrices. We derive error correlations in a priori combustion source estimates of CO2 and CO by propagating error estimates of fuel consumption rates and emission factors. However, we find that these correlations are weak because CO source uncertainties are mostly determined by emission factors. Observed correlations between atmospheric CO2 and CO concentrations imply corresponding error correlations in the chemical transport model used as the forward model for the inversion. These error correlations in excess of 0.7, as derived from the TRACE-P data, enable a coupled CO2-CO inversion to achieve significant improvement over a CO2-only inversion for quantifying regional fluxes of CO2. C1 Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Shanghai Environm Monitoring Ctr, Shanghai 200030, Peoples R China. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Palmer, PI (reprint author), Univ Leeds, Sch Earth & Environm, Leeds LS2 9JT, W Yorkshire, England. EM pip@env.leeds.ac.uk RI Palmer, Paul/F-7008-2010; Jones, Dylan/O-2475-2014; OI Jones, Dylan/0000-0002-1935-3725; Streets, David/0000-0002-0223-1350 NR 30 TC 36 Z9 36 U1 1 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 JUN 30 PY 2006 VL 111 IS D12 AR D12318 DI 10.1029/2005JD006697 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 062IX UT WOS:000238938900004 ER PT J AU Thompson, TW Campbell, BA Ghent, RR Hawke, BR Leverington, DW AF Thompson, Thomas W. Campbell, Bruce A. Ghent, Rebecca R. Hawke, B. Ray Leverington, David W. TI Radar probing of planetary regoliths: An example from the northern rim of Imbrium basin SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID LUNAR; MARS; DEPOSITS; REGION; MOON; WAVELENGTH; IMAGES AB [ 1] Imaging radar measurements at long wavelengths ( e. g., > 30 cm) allow deep ( up to tens of meters) probing of the physical structure and dielectric properties of planetary regoliths. We illustrate a potential application for a Mars orbital synthetic aperture radar ( SAR) using new Earth- based 70-cm wavelength radar data for the Moon. The terrae on the northern margin of Mare Imbrium, the Montes Jura region, have diffuse radar backscatter echoes that are 2 - 4 times weaker at 3.8- cm, 70- cm, and 7.5- m wavelengths than most other lunar nearside terrae. Possible geologic explanations are ( 1) a pyroclastic deposit associated with sinuous rilles in this region, ( 2) buried mare basalt or a zone of mixed highland/ basaltic debris ( cryptomaria), or ( 3) layers of ejecta associated with the Iridum and Plato impacts that have fewer meter-sized rocks than typical highlands regolith. While radar data at 3.8- cm to 7.5- m wavelengths suggest significant differences between the Montes Jura region and typical highlands, the surface geochemistry and rock abundance inferred from Clementine UV-VIS data and eclipse thermal images are consistent with other lunar terrae. There is no evidence for enhanced iron abundance, expected for basaltic pyroclastic deposits, near the source vents of the sinuous rilles radial to Plato. The regions of low 70- cm radar return are consistent with overlapping concentric "haloes'' about Iridum and Plato and do not occur preferentially in topographically low areas, as is observed for radar-mapped cryptomaria. Thus we suggest that the extensive radar-dark area associated with the Montes Jura region is due to overlapping, rock-poor ejecta deposits from Iridum and Plato craters. Comparison of the radial extent of low-radar-return crater haloes with a model for ejecta thickness shows that these rock-poor layers are detected by 70- cm radar where they are on the order of 10 m and thicker. A SAR in orbit about Mars could use similar deep probing to reveal the nature of crater-and basin-related deposits. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Smithsonian Inst, Natl Air & Space Museum, Ctr Earth & Planetary Studies, Washington, DC 20013 USA. Univ Hawaii, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. RP Thompson, TW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 300-227, Pasadena, CA 91109 USA. EM thomas.w.thompson@jpl.nasa.gov; campbellb@si.edu; ghentr@si.edu; hawke@higp.hawaii.edu; david.leverington@ttu.edu NR 30 TC 12 Z9 13 U1 0 U2 4 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 JUN 30 PY 2006 VL 111 IS E6 AR E06S14 DI 10.1029/2005JE002566 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 062KE UT WOS:000238942200002 ER PT J AU Nagy, AF Kliore, AJ Marouf, E French, R Flasar, M Rappaport, NJ Anabtawi, A Asmar, SW Johnston, D Barbinis, E Goltz, G Fleischman, D AF Nagy, Andrew F. Kliore, Arvydas J. Marouf, Essam French, Richard Flasar, Michael Rappaport, Nicole J. Anabtawi, Aseel Asmar, Sami W. Johnston, Douglas Barbinis, Elias Goltz, Gene Fleischman, Don TI First results from the ionospheric radio occultations of Saturn by the Cassini spacecraft SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ATMOSPHERE; MODEL AB The first set of near-equatorial occultations of the Saturn ionosphere was obtained by the Cassini spacecraft between May and September of 2005. The occultations occurred at near-equatorial latitudes, between 10 degrees N and 10 degrees S, at solar zenith angles from about 84 degrees to 96 degrees. The entry observations correspond to dusk conditions and the exit ones to dawn. An initial look at the data indicates that the average peak densities are lower and the peak altitude higher at dawn than at dusk, possibly the result of ionospheric decay during the night hours. There are also significant differences between individual dawn and dusk occultations; the initial thought is that this variation must be connected to changes in the water inflow into the upper atmosphere and/or variations in the particle impact ionization rates. C1 Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. San Jose State Univ, Dept Elect Engn, San Jose, CA 95192 USA. Wellesley Coll, Dept Astron, Wellesley, MA 02481 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Nagy, AF (reprint author), Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. EM anagy@umich.edu RI Flasar, F Michael/C-8509-2012 NR 15 TC 34 Z9 34 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-SPACE JI J. Geophys. Res-Space Phys. PD JUN 30 PY 2006 VL 111 IS A6 AR A06310 DI 10.1029/2005JA011519 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 062KO UT WOS:000238943200001 ER PT J AU Brown, GV Beiersdorfer, P Chen, H Scofield, JH Boyce, KR Kelley, RL Kilbourne, CA Porter, FS Gu, MF Kahn, SM Szymkowiak, AE AF Brown, G. V. Beiersdorfer, P. Chen, H. Scofield, J. H. Boyce, K. R. Kelley, R. L. Kilbourne, C. A. Porter, F. S. Gu, M. F. Kahn, S. M. Szymkowiak, A. E. TI Energy-dependent excitation cross section measurements of the diagnostic lines of Fe XVII SO PHYSICAL REVIEW LETTERS LA English DT Article ID X-RAY-SPECTRUM; REFLECTION GRATING SPECTROMETER; HIGHLY CHARGED IONS; LABORATORY MEASUREMENTS; XMM-NEWTON; COLLISION STRENGTHS; RELATIVE INTENSITY; SOLAR; SPECTROSCOPY; TRANSITIONS AB By implementing a large-area, gain-stabilized microcalorimeter array on an electron beam ion trap, the electron-impact excitation cross sections for the dominant x-ray lines in the Fe XVII spectrum have been measured as a function of electron energy establishing a benchmark for atomic calculations. The results show that the calculations consistently predict the cross section of the resonance line to be significantly larger than measured. The lower cross section accounts for several problems found when modeling solar and astrophysical Fe XVII spectra. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Stanford Univ, Kavli Inst Particle Astrophys & Cosmol, Stanford, CA 94305 USA. Yale Univ, Dept Phys, New Haven, CT 06520 USA. RP Brown, GV (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 32 TC 52 Z9 52 U1 0 U2 2 PU AMER 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 JUN 30 PY 2006 VL 96 IS 25 AR 253201 DI 10.1103/PhysRevLett.96.253201 PG 4 WC Physics, Multidisciplinary SC Physics GA 058XD UT WOS:000238697000015 PM 16907303 ER PT J AU Dufour, G Nassar, R Boone, CD Skelton, R Walker, KA Bernath, PF Rinsland, CP Semeniuk, K Jin, JJ McConnell, JC Manney, GL AF Dufour, G. Nassar, R. Boone, C. D. Skelton, R. Walker, K. A. Bernath, P. F. Rinsland, C. P. Semeniuk, K. Jin, J. J. McConnell, J. C. Manney, G. L. TI Partitioning between the inorganic chlorine reservoirs HCl and ClONO2 during the Arctic winter 2005 from the ACE-FTS SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID LOWER STRATOSPHERE; OZONE DEPLETION; POLAR VORTEX; UARS; CHEMISTRY; MODEL; DEACTIVATION; CLIMATOLOGY; PROFILES; HNO3 AB From January to March 2005, the Atmospheric Chemistry Experiment high resolution Fourier transform spectrometer (ACE-FTS) on SCISAT-1 measured many of the changes occurring in the Arctic ( 50 - 80 degrees N) lower stratosphere under very cold winter conditions. Here we focus on the partitioning between the inorganic chlorine reservoirs HCl and ClONO2 and their activation into ClO. The simultaneous measurement of these species by the ACE-FTS provides the data needed to follow chlorine activation during the Arctic winter and the recovery of the Cl-reservoir species ClONO2 and HCl. The time evolution of HCl, ClONO2 and ClO as well as the partitioning between the two reservoir molecules agrees well with previous observations and with our current understanding of chlorine activation during Arctic winter. The results of a chemical box model are also compared with the ACE-FTS measurements and are generally consistent with the measurements. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. York Univ, Dept Space Sci & Engn, N York, ON M3J 1P3, Canada. CALTECH, NASA, Jet Prop Lab, Pasadena, CA 91125 USA. New Mexico Inst Min & Technol, Socorro, NM 87801 USA. Univ Waterloo, Dept Chem, Waterloo, ON N2L 3G1, Canada. RP Dufour, G (reprint author), Inst Pierre Simon Laplace, Meteorol Dynam Lab, Palaiseau, France. EM gaelle.dufour@lmd.polytechnique.fr RI Bernath, Peter/B-6567-2012; Jin, Jianjun/G-8357-2012; OI Bernath, Peter/0000-0002-1255-396X; Nassar, Ray/0000-0001-6282-1611 NR 39 TC 19 Z9 19 U1 1 U2 2 PU COPERNICUS GESELLSCHAFT MBH PI GOTTINGEN PA BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY SN 1680-7316 EI 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JUN 29 PY 2006 VL 6 BP 2355 EP 2366 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 058OZ UT WOS:000238675600001 ER PT J AU Rosenfeld, D Kaufman, YJ Koren, I AF Rosenfeld, D Kaufman, YJ Koren, I TI Switching cloud cover and dynamical regimes from open to closed Benard cells in response to the suppression of precipitation by aerosols SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID MARINE BOUNDARY-LAYER; MESOSCALE CELLULAR CONVECTION; STRATOCUMULUS CLOUDS; STRATIFORM CLOUDS; AIR-POLLUTION; SHIP TRACKS; DRIZZLE; OCEAN; MICROPHYSICS; ENTRAINMENT AB The dynamic structure of the weakly sheared atmospheric marine boundary layer (MBL) supports three distinct states of cloud cover, which are associated with the concentrations of cloud condensation nuclei (CCN) aerosols in the MBL: (i) CCN rich MBL with closed Benard cellular convection that forms nearly full cloud cover; (ii) CCN depleted MBL with open cellular convection that forms < 40% cloud cover; and, (iii) CCN starved MBL where clouds cannot form due to insufficient CCN, with near zero cloud cover. Here we propose a mechanism for the transition between these three states that involves the aerosol impacts on precipitation and the feedbacks on the dynamics of the clouds and on the aerosols deposition. By suppressing precipitation aerosols can reverse the direction of the airflow, converting the cloud structure from open to closed cells and more than doubling the cloud cover. The three states possess positive feedbacks for self maintenance, so that small changes of the conditions can lead to bifurcation of the MBL cloud regime. The transition between the closed and open cells occur at near pristine background level of aerosols, creating a large sensitivity of cloud radiative forcing to very small changes in aerosols at the MBL. The third state of super clean air can occur as the more efficient precipitation in cleaner air deposits the aerosols ever faster in a runaway positive feedback process. The proposed mechanism suggests that very small changes in the aerosols input to the MBL can have large impacts on the oceanic cloud cover and likely in turn on the global temperature, in ways that are not yet accounted for in the climate models. C1 Hebrew Univ Jerusalem, Inst Earth Sci, IL-91904 Jerusalem, Israel. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Weizmann Inst Sci, Dept Environm Sci, IL-76100 Rehovot, Israel. RP Rosenfeld, D (reprint author), Hebrew Univ Jerusalem, Inst Earth Sci, IL-91904 Jerusalem, Israel. EM daniel.rosenfeld@huji.huji.ac.il RI Koren, Ilan/K-1417-2012; Rosenfeld, Daniel/F-6077-2016 OI Koren, Ilan/0000-0001-6759-6265; Rosenfeld, Daniel/0000-0002-0784-7656 NR 34 TC 58 Z9 59 U1 0 U2 11 PU EUROPEAN GEOSCIENCES UNION PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 1680-7316 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JUN 29 PY 2006 VL 6 BP 2503 EP 2511 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 058OZ UT WOS:000238675600011 ER PT J AU Moradkhani, H Hsu, K Hong, Y Sorooshian, S AF Moradkhani, Hamid Hsu, K. Hong, Y. Sorooshian, S. TI Investigating the impact of remotely sensed precipitation and hydrologic model uncertainties on the ensemble streamflow forecasting SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PARAMETER-ESTIMATION; DATA ASSIMILATION; SIMULATION; STRENGTHS; FILTER AB In the past few years sequential data assimilation (SDA) methods have emerged as the best possible method at hand to properly treat all sources of error in hydrological modeling. However, very few studies have actually implemented SDA methods using realistic input error models for precipitation. In this study we use particle filtering as a SDA method to propagate input errors through a conceptual hydrologic model and quantify the state, parameter and streamflow uncertainties. Recent progress in satellite-based precipitation observation techniques offers an attractive option for considering spatiotemporal variation of precipitation. Therefore, we use the PERSIANN-CCS precipitation product to propagate input errors through our hydrologic model. Some uncertainty scenarios are set up to incorporate and investigate the impact of the individual uncertainty sources from precipitation, parameters and also combined error sources on the hydrologic response. Also probabilistic measures are used to quantify the quality of ensemble prediction. C1 Univ Calif Irvine, Dept Civil & Environm Engn, Ctr Hydrometeorol & Remote Sensing, Irvine, CA 92697 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Moradkhani, H (reprint author), Univ Calif Irvine, Dept Civil & Environm Engn, Ctr Hydrometeorol & Remote Sensing, Irvine, CA 92697 USA. EM moradkha@uci.edu RI Hong, Yang/D-5132-2009; sorooshian, soroosh/B-3753-2008; Moradkhani, Hamid/B-1571-2012 OI Hong, Yang/0000-0001-8720-242X; sorooshian, soroosh/0000-0001-7774-5113; NR 11 TC 32 Z9 32 U1 0 U2 7 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 JUN 29 PY 2006 VL 33 IS 12 AR L12107 DI 10.1029/2006GL026855 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 062II UT WOS:000238937400003 ER PT J AU Brinks, HW Fossdal, A Bowman, RC Hauback, BC AF Brinks, HW Fossdal, A Bowman, RC Hauback, BC TI Pressure-composition isotherms of TbNiAlHx SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE metal hydrides; pressure-composition isotherms; terbium aluminium hydride ID HYDROGEN AB Accurate isotherms of TbNiAlHx were measured at 60, 150, 200, 250 degrees C with a Sieverts-type apparatus. The intermediate TbNiAlH0.33 and TbNiAlHx, (0.4 < x < 0.6) hydrides were confirmed to be present at the higher temperatures. Orthorhombic TbNiAlHx (x > 0.9) was detected at all temperatures. The hydrogen content after desorption at 10 mbar and 60 degrees C is similar to prolonged storage at room temperature. The reaction between hexagonal ThNiAlH0.6 and orthorhombic ThNiAlH0.9 was found to have a desorption enthalpy of 50.7 kJ/(mol H-2). Methodology and requirements for making accurate measurements of isotherms are discussed. (c) 2005 Elsevier B.V. All rights reserved. C1 Inst Energy Technol, Dept Phys, NO-2027 Kjeller, Norway. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Brinks, HW (reprint author), Inst Energy Technol, Dept Phys, POB 40, NO-2027 Kjeller, Norway. EM hwbrinks@ife.no OI Bowman, Robert/0000-0002-2114-1713 NR 7 TC 6 Z9 6 U1 0 U2 5 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 JUN 29 PY 2006 VL 417 IS 1-2 BP 92 EP 95 DI 10.1016/j.jallcom.2005.09.018 PG 4 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 055RT UT WOS:000238468800020 ER PT J AU Zhou, YH Salstein, DA Chen, JL AF Zhou, Y. H. Salstein, D. A. Chen, J. L. TI Revised atmospheric excitation function series related to Earth's variable rotation under consideration of surface topography SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ANGULAR-MOMENTUM FLUCTUATIONS; POLAR MOTION; LENGTH; OCEAN; VARIABILITY; MODELS AB [ 1] The atmospheric angular momentum is closely related to variations in the Earth rotation. The atmospheric excitation function ( AEF), known also as the atmospheric effective angular momentum function, is introduced in studying the atmospheric excitation of the Earth's variable rotation. It may be separated into two portions, i.e., the "wind'' terms due to the atmospheric motion relative to the mantle and the "pressure'' terms due to the variations of atmospheric mass distribution evident through surface pressure changes. The AEF wind terms during the period of 1948 - 2004 are reprocessed from the National Centers for Environmental Prediction- National Center for Atmospheric Research (NCEP/NCAR) reanalysis 6-hourly wind and pressure fields. Some previous calculations were approximate, in that the wind terms were integrated from an isobaric lower boundary of 1000 hPa. To consider the surface topography effect, however, the AEF is computed by integration using the winds from the Earth's surface to 10 hPa, the top atmospheric model level, instead of from 1000 hPa. For these two cases, only a minor difference, equivalent to similar to 0.004 ms in length-of-day variation, exists with respect to the axial wind term. However, considerable differences, equivalent to 5 similar to 6 milliseconds of arc in polar motion, are found regarding equatorial wind terms. We further compare the total equatorial AEF ( with and without the topography effect) with the polar motion excitation function (PMEF) during the period of 1980 - 2003. The equatorial AEF gets generally closer to the PMEF, and improved coherences are found between them when the topography effect is included. C1 Chinese Acad Sci, Shanghai Astron Observ, Shanghai 20030, Peoples R China. Atmospher & Environm Res Inc, Lexington, MA 02421 USA. Univ Maryland, NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. Univ Texas, Ctr Space Res, Austin, TX 78712 USA. RP Zhou, YH (reprint author), Chinese Acad Sci, Shanghai Astron Observ, Shanghai 20030, Peoples R China. EM yhzhou@shao.ac.cn NR 32 TC 37 Z9 38 U1 0 U2 1 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 JUN 29 PY 2006 VL 111 IS D12 AR D12108 DI 10.1029/2005JD006608 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 062IW UT WOS:000238938800001 ER PT J AU Tsurutani, BT Gonzalez, WD Gonzalez, ALC Guarnieri, FL Gopalswamy, N Grande, M Kamide, Y Kasahara, Y Lu, G Mann, I McPherron, R Soraas, F Vasyliunas, V AF Tsurutani, Bruce T. Gonzalez, Walter D. Gonzalez, Alicia L. C. Guarnieri, Fernando L. Gopalswamy, Nat Grande, Manuel Kamide, Yohsuke Kasahara, Yoshiya Lu, Gang Mann, Ian McPherron, Robert Soraas, Finn Vasyliunas, Vytenis TI Corotating solar wind streams and recurrent geomagnetic activity: A review SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Review ID INTERPLANETARY MAGNETIC-FIELD; RADIATION BELT ELECTRONS; NONLINEAR ALFVEN WAVES; OUTER ZONE ELECTRONS; WHISTLER-MODE CHORUS; POLAR CORONAL HOLES; DP 2 FLUCTUATIONS; RELATIVISTIC ELECTRONS; ROTATIONAL DISCONTINUITIES; INTERACTION REGIONS AB [ 1] Solar wind fast streams emanating from solar coronal holes cause recurrent, moderate intensity geomagnetic activity at Earth. Intense magnetic field regions called Corotating Interaction Regions or CIRs are created by the interaction of fast streams with upstream slow streams. Because of the highly oscillatory nature of the GSM magnetic field z component within CIRs, the resultant magnetic storms are typically only weak to moderate in intensity. CIR-generated magnetic storm main phases of intensity Dst < - 100 nT ( major storms) are rare. The elongated storm "recovery'' phases which are characterized by continuous AE activity that can last for up to 27 days ( a solar rotation) are caused by nonlinear Alfven waves within the high streams proper. Magnetic reconnection associated with the southward (GSM) components of the Alfven waves is the solar wind energy transfer mechanism. The acceleration of relativistic electrons occurs during these magnetic storm "recovery'' phases. The magnetic reconnection associated with the Alfven waves cause continuous, shallow injections of plasma sheet plasma into the magnetosphere. The asymmetric plasma is unstable to wave ( chorus and other modes) growth, a feature central to many theories of electron acceleration. It is noted that the continuous AE activity is not a series of substorm expansion phases. Arguments are also presented why these AE activity intervals are not convection bays. The auroras during these continuous AE activity intervals are less intense than substorm auroras and are global ( both dayside and nightside) in nature. Owing to the continuous nature of this activity, it is possible that there is greater average energy input into the magnetosphere/ ionosphere system during far declining phases of the solar cycle compared with those during solar maximum. The discontinuities and magnetic decreases (MDs) associated with interplanetary Alfven waves may be important for geomagnetic activity. In conclusion, it will be shown that geomagnetic storms associated with high-speed streams/CIRs will have the same initial, main, and "recovery'' phases as those associated with ICME-related magnetic storms but that the interplanetary causes are considerably different. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Kyoto Univ, Uji, Kyoto, Japan. Inst Nacl Pesquisas Espaciais, BR-1220970 Sao Jose Dos Campos, SP, Brazil. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Rutherford Appleton Lab, Planets & Magnetospheres Grp, Didcot OX11 0QX, Oxon, England. Nagoya Univ, Solar Terr Environm Lab, Toyokawa, Aichi 4428507, Japan. Kanazawa Univ, Dept Informat & Syst Engn, Kanazawa, Ishikawa 9201192, Japan. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80301 USA. Univ Alberta, Dept Phys, Edmonton, AB, Canada. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA. Univ Bergen, Dept Phys & Technol, N-5007 Bergen, Norway. Max Planck Inst Solar Syst Res, D-37195 Lindau, Germany. RP Tsurutani, BT (reprint author), CALTECH, Jet Prop Lab, MS 169-506,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM bruce.tsurutani@jpl.nasa.gov RI Lu, Gang/A-6669-2011; Gopalswamy, Nat/D-3659-2012; Grande, Manuel/C-2242-2013 OI Grande, Manuel/0000-0002-2233-2618 NR 115 TC 233 Z9 234 U1 4 U2 26 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 JUN 29 PY 2006 VL 111 IS A7 AR A07S01 DI 10.1029/2005JA011273 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 062KP UT WOS:000238943300001 ER PT J AU Tu, JN Song, P Reinisch, BW Green, JL Huang, XQ AF Tu, Jiannan Song, Paul Reinisch, Bodo W. Green, James L. Huang, Xueqin TI Empirical specification of field-aligned plasma density profiles for plasmasphere refilling SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ELECTRON-DENSITY; GEOSYNCHRONOUS ORBIT; MAGNETOSPHERE; MODEL; IMAGE; DEPENDENCE; GEOS-2; TUBE; RPI AB Sounding measurements from the radio plasma imager (RPI) on the IMAGE satellite are used to derive electron density distributions along magnetic field lines in the nightside plasmasphere and plasmatrough for three midlatitude passes. These passes occurred during (1) a magnetic storm, (2) a prolonged quiet time, and (3) a sudden commencement of a storm, respectively. It is found that the density profiles of filled (in the inner plasmasphere) and depleted ( in the plasmatrough or outer plasmasphere) flux tubes have different field line dependence. A multivariant least squares fit with a simple analytical function is used to model the density profiles. The fitting parameters in the function define the field line dependence of a density profile, i.e., the steepness of the density profile at high latitudes and the flatness at low latitudes. In each pass the density profiles along the filled and depleted flux tubes can be well modeled with the selected functional form, with two different sets of fitting parameter values for filled and depleted flux tubes. For the three passes examined, the fitting parameter values are not sensitive to the geomagnetic activity for the inner plasmasphere density profiles but vary slightly for the plasmatrough or outer plasmasphere density profiles from case to case. The equatorial densities extrapolated from the measured density profiles approximately have a power law relation with L values. The results suggest that the selected function has potential of being able to construct realistic global empirical plasmasphere/ plasmatrough models. Furthermore, it is now feasible to empirically determine the density profiles along the depleted flux tubes for plasmasphere refilling studies. 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 30 TC 24 Z9 24 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 JUN 29 PY 2006 VL 111 IS A6 AR A06216 DI 10.1029/2005JA011582 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 062KN UT WOS:000238943100004 ER PT J AU Summons, RE Bradley, AS Jahnke, LL Waldbauer, JR AF Summons, Roger E. Bradley, Alexander S. Jahnke, Linda L. Waldbauer, Jacob R. TI Steroids, triterpenoids and molecular oxygen SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES LA English DT Article; Proceedings Paper CT Conference on Major Steps in Cell Evolution - Palaeontological, Molecular and Cellular Evidence of their Timing and Global Effects CY SEP 26-27, 2005 CL Royal Soc, London, ENGLAND HO Royal Soc DE Archaean; biomarker hydrocarbons; steroids; sterols; triterpenoids; hopanes aerobic biosynthesis ID PALEOPROTEROZOIC SNOWBALL EARTH; BLUE-GREEN-ALGAE; ATMOSPHERIC OXYGEN; SACCHAROMYCES-CEREVISIAE; OXIDOSQUALENE CYCLASE; SQUALENE EPOXIDASE; LANOSTEROL 14-ALPHA-DEMETHYLASE; 14-ALPHA-STEROL DEMETHYLASE; MYCOBACTERIUM-TUBERCULOSIS; DIRECTED EVOLUTION AB There is a close connection between modern-day biosynthesis of particular triterpenoid biomarkers and presence of molecular oxygen in the environment. Thus, the detection of steroid and triterpenoid hydrocarbons far back in Earth history has been used to infer the antiquity of oxygenic photosynthesis. This prompts the question: were these compounds produced similarly in the past? In this paper, we address this question with a review of the current state of knowledge surrounding the oxygen requirement for steroid biosynthesis and phylogenetic patterns in the distribution of steroid and triterpenoid biosynthetic pathways. The hopanoid and steroid biosynthetic pathways are very highly conserved within the bacterial and eukaryotic domains, respectively. Bacteriohopanepolyols are produced by a wide range of bacteria, and are methylated in significant abundance at the C2 position by oxygen-producing cyanobacteria. On the other hand, sterol biosynthesis is sparsely distributed in distantly related bacterial taxa and the pathways do not produce the wide range of products that characterize eukaryotes. In particular, evidence for sterol biosynthesis by cyanobacteria appears flawed. Our experiments show that cyanobacterial cultures are easily contaminated by sterol-producing rust fungi, which can be eliminated by treatment with cycloheximide affording sterol-free samples. Sterols are ubiquitous features of eukaryotic membranes, and it appears likely that the initial steps in sterol biosynthesis were present in their modern form in the last common ancestor of eukaryotes. Eleven molecules of O-2 are required by four enzymes to produce one molecule of cholesterol. Thermodynamic arguments, optimization of function and parsimony all indicate that an ancestral anaerobic pathway is highly unlikely. The known geological record of molecular fossils, especially steranes and triterpanes, is notable for the limited number of structural motifs that have been observed. With a few exceptions, the carbon skeletons are the same as those found in the lipids of extant organisms and no demonstrably extinct structures have been reported. Furthermore, their patterns of occurrence over billion year time-scales correlate strongly with environments of deposition. Accordingly, biomarkers are excellent indicators of environmental conditions even though the taxonomic affinities of all biomarkers cannot be precisely specified. Biomarkers are ultimately tied to biochemicals with very specific functional properties, and interpretations of the biomarker record will benefit from increased understanding of the biological roles of geologically durable molecules. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. NASA, Ames Res Ctr, Planetary Biol Branch, Moffett Field, CA 94035 USA. Woods Hole Oceanog Inst, Joint Program Chem Oceanog, Cambridge, MA 02139 USA. RP Summons, RE (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, 77 Massachusetts Ave E34-246, Cambridge, MA 02139 USA. EM rsummons@mit.edu RI Bradley, Alexander/A-9391-2009 OI Bradley, Alexander/0000-0002-4044-2802 NR 124 TC 141 Z9 151 U1 2 U2 28 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 0962-8436 EI 1471-2970 J9 PHILOS T R SOC B JI Philos. Trans. R. Soc. B-Biol. Sci. PD JUN 29 PY 2006 VL 361 IS 1470 BP 951 EP 968 DI 10.1098/rstb.2006.1837 PG 18 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 054EL UT WOS:000238359500008 PM 16754609 ER PT J AU Heggy, E Clifford, SM Farr, TG Dinwiddie, CL Grimm, RE AF Heggy, Essam Clifford, Stephen M. Farr, Tom G. Dinwiddie, Cynthia L. Grimm, Robert E. TI Radar investigations of planetary and terrestrial environments SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article C1 Lunar & Planetary Inst, Houston, TX 77058 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. SW Res Inst, Dept Space Studies, Boulder, CO 80302 USA. SW Res Inst, Dept Earth Mat & Planetary Sci, San Antonio, TX 78238 USA. RP Heggy, E (reprint author), Lunar & Planetary Inst, 3600 Bay Area Blvd, Houston, TX 77058 USA. EM heggy@lpi.usra.edu RI Dinwiddie, Cynthia/C-1385-2008; Heggy, Essam/E-8250-2013; OI Dinwiddie, Cynthia/0000-0003-4673-1063; Heggy, Essam/0000-0001-7476-2735; Grimm, Robert/0000-0002-7588-1194; Farr, Thomas/0000-0001-5406-2096 NR 4 TC 0 Z9 0 U1 1 U2 2 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 JUN 28 PY 2006 VL 111 IS E6 AR E06S01 DI 10.1029/2006JE002759 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 062KB UT WOS:000238941900001 ER PT J AU Sun, XH Didychuk, C Sham, TK Wong, NB AF Sun, XH Didychuk, C Sham, TK Wong, NB TI Germanium nanowires: synthesis, morphology and local structure studies SO NANOTECHNOLOGY LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; SCIENCE-AND-TECHNOLOGY; X-RAY-ABSORPTION; SILICON NANOWIRES; SEMICONDUCTOR NANOWIRES; ELECTRONIC-STRUCTURE; BUILDING-BLOCKS; GROWTH; NANOSTRUCTURES; NANOPARTICLES AB Germanium nanowires (GeNWs) have been synthesized by the thermal evaporation of Ge powder at 950 degrees C onto silicon wafer and ceramic ( alumina) substrate using Au nanoparticles as a catalyst via a vapour - liquid - solid (VLS) process. The morphology, crystal structure and growth direction of the as-prepared GeNWs have been characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), and transmission electron microscopy (TEM). GeNWs are uniform with a diameter of similar to 30 nm and lengths of tens of micrometres. High-resolution TEM shows that an individual GeNW is a single crystal with a diamond structure and a preferred growth along the [111] direction. Au nanoparticles are found at the tip of GeNWs indicating that the growth of GeNWs follows a VLS mechanism. The electronic and local structures of the as-prepared GeNWs have also been investigated by x-ray absorption fine structure spectroscopy (XAFS). The results and the implications will be discussed. C1 Univ Western Ontario, Dept Chem, London, ON N6A 5B7, Canada. City Univ Hong Kong, Dept Biol & Chem, Hong Kong, Hong Kong, Peoples R China. RP Sun, XH (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. EM tsham@uwo.ca RI Wong, Ning Bew/C-4569-2008; Sun, Xuhui /K-5689-2012 NR 38 TC 31 Z9 32 U1 0 U2 16 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0957-4484 J9 NANOTECHNOLOGY JI Nanotechnology PD JUN 28 PY 2006 VL 17 IS 12 BP 2925 EP 2930 DI 10.1088/0957-4484/17/12/017 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Science & Technology - Other Topics; Materials Science; Physics GA 052TH UT WOS:000238256300017 ER PT J AU Johannes, LB Yowell, LL Sosa, E Arepalli, S Mishra, RS AF Johannes, Lucie B. Yowell, Leonard L. Sosa, Edward Arepalli, Sivaram Mishra, Rajiv S. TI Survivability of single-walled carbon nanotubes during friction stir processing SO NANOTECHNOLOGY LA English DT Article ID RAMAN-SCATTERING; COMPOSITES; FABRICATION; SENSORS; FIBER AB Single-walled carbon nanotubes (SWCNTs) were added to aluminium using friction stir processing (FSP). The SWCNTs survived the thermal and stress cycles involved with friction stir processing. The Raman spectroscopy and SEM results are presented. Potential applications of nanotubes inserted into metals by this method are discussed. C1 Univ Missouri, Dept Mat Sci & Engn, Rolla, MO 65401 USA. NASA, Lyndon B Johnson Space Ctr, Mat Proc Branch ES5, Houston, TX 77058 USA. ERC Inc, NASA, JSC, Houston, TX 77058 USA. RP Mishra, RS (reprint author), Univ Missouri, Dept Mat Sci & Engn, Rolla, MO 65401 USA. EM rsmishra@umr.edu RI Mishra, Rajiv/A-7985-2009; Arepalli, Sivaram/A-5372-2010; OI Mishra, Rajiv/0000-0002-1699-0614; Johannes, Lucie/0000-0001-8867-9465 NR 28 TC 26 Z9 29 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0957-4484 J9 NANOTECHNOLOGY JI Nanotechnology PD JUN 28 PY 2006 VL 17 IS 12 BP 3081 EP 3084 DI 10.1088/0957-4484/17/12/044 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Science & Technology - Other Topics; Materials Science; Physics GA 052TH UT WOS:000238256300044 ER PT J AU Tsurutani, BT Guarnieri, FL Fuller-Rowell, T Mannucci, AJ Iijima, B Gonzalez, WD Judge, DL Gangopadhyay, P Saito, A Tsuda, T Verkhoglyadova, OP Zambon, GA AF Tsurutani, B. T. Guarnieri, F. L. Fuller-Rowell, T. Mannucci, A. J. Iijima, B. Gonzalez, W. D. Judge, D. L. Gangopadhyay, P. Saito, A. Tsuda, T. Verkhoglyadova, O. P. Zambon, G. A. TI Extreme solar EUV flares and ICMEs and resultant extreme ionospheric effects: Comparison of the Halloween 2003 and the Bastille Day events SO RADIO SCIENCE LA English DT Article ID GREAT MAGNETIC STORM; ELECTRIC-FIELD; PIONEER-11; SYSTEM; REGION; SHOCKS AB [ 1] Extreme solar flares can cause extreme ionospheric effects. The 28 October 2003 flare caused a similar to 25 total electron content units (TECU = 10(16) el/m(2) column density), or a similar to 30%, increase in the local noon equatorial ionospheric column density. The rise in the TEC enhancement occurred in similar to 5 min. This TEC increase was similar to 5 times the TEC increases detected for the 29 October and the 4 November 2003 flares and the 14 July 2000 (Bastille Day) flare. In the 260 - 340 angstrom EUV wavelength range, the 28 October flare peak count rate was more than twice as large as for the other three flares. Another strong ionospheric effect is the delayed influence of the interplanetary coronal mass ejection (ICME) electric fields on the ionosphere. For the 28 and 29 October flares, the associated ICMEs propagated from the Sun to the Earth at particularly high speeds. The prompt penetration of the interplanetary electric fields (IEFs) caused the dayside near-equatorial ionosphere to be strongly uplifted by E x B convection. Consequential diffusion of the uplifted plasma down the Earth's magnetic field lines to higher magnetic latitudes is a major plasma transport process during these IEF (superstorm) events. Such diffusion should lead to inverted midlatitude ionospheres ( oxygen ions at higher altitudes than protons). The energy input into the midlatitude ionospheres by this superfountain phenomenon could lead to local dayside midlatitude disturbance dynamos, features which cannot propagate from the nightside auroral zones. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ So Calif, Dept Phys & Astron, Los Angeles, CA 90089 USA. Kyoto Univ, Res Inst Sustainable Humanosphere, Uji, Japan. NOAA, Space Environm Ctr, Boulder, CO 80303 USA. Kyoto Univ, Dept Geophys, Sakyou Ku, Kyoto 6068502, Japan. Univ Calif Riverside, Inst Geophys & Planetary Phys, Riverside, CA 92521 USA. RP Tsurutani, BT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM bruce.tsurutani@jpl.nasa.gov RI tsuda, toshitaka/A-3035-2015; OI Verkhoglyadova, Olga/0000-0002-9295-9539 NR 22 TC 12 Z9 12 U1 1 U2 2 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 JUN 28 PY 2006 VL 41 IS 5 AR RS5S07 DI 10.1029/2005RS003331 PG 7 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 062KS UT WOS:000238943700001 ER PT J AU Schoeberl, MR Duncan, BN Douglass, AR Waters, J Livesey, N Read, W Filipiak, M AF Schoeberl, M. R. Duncan, B. N. Douglass, A. R. Waters, J. Livesey, N. Read, W. Filipiak, M. TI The carbon monoxide tape recorder SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TROPICAL TROPOPAUSE LAYER; GENERAL-CIRCULATION MODEL; BIOMASS BURNING EMISSIONS; AGE SPECTRA; WATER-VAPOR; TRANSPORT; STRATOSPHERE; DEHYDRATION; CONVECTION; TROPOSPHERE AB Using Aura MLS data we have identified the stratospheric 'tape recorder' in carbon monoxide ( CO). Unlike the water vapor tape recorder, which is forced by the upper tropospheric seasonal variation in dehydration processes, the CO tape recorder is linked to seasonal changes in biomass burning. Since CO has a chemical lifetime of only a few months, the CO tape recorder barely extends above 20 km. The tape head for CO appears to be close to 360 K near the same location as the water vapor tape head ( Read et al., 2004). Both tape heads are below the equatorial cold point tropopause but above the base of the tropical tropopause layer. The Global Modeling Initiative chemical transport model forced by the climatology of biomass burning reproduces the CO tape recorder. The tape recorder signal in the GMI model becomes more distinct from 360 K to 380 K suggesting that convective detrainment plays a decreasingly important role with altitude. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Jet Propuls Lab, Pasadena, CA 91109 USA. Univ Edinburgh, Sch Geosci, Edinburgh EH9 3JN, Midlothian, Scotland. RP Schoeberl, MR (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM mark.r.schoeberl@nasa.gov RI Duncan, Bryan/A-5962-2011; Douglass, Anne/D-4655-2012 NR 30 TC 65 Z9 66 U1 0 U2 5 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 JUN 27 PY 2006 VL 33 IS 12 AR L12811 DI 10.1029/2006GL026178 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 062HU UT WOS:000238936000004 ER PT J AU Unger, N Shindell, DT Koch, DM Amann, M Cofala, J Streets, DG AF Unger, Nadine Shindell, Drew T. Koch, Dorothy M. Amann, Markus Cofala, Janusz Streets, David G. TI Influences of man-made emissions and climate changes on tropospheric ozone, methane, and sulfate at 2030 from a broad range of possible futures SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; REGIONAL EMISSIONS; GREENHOUSE-GAS; GLOBAL-MODEL; CHEMISTRY; SIMULATIONS; PRECURSORS; TRANSPORT; POLLUTION; IMPACTS AB [ 1] We apply the Goddard Institute for Space Studies composition-climate model to an assessment of tropospheric O-3, CH4, and sulfate at 2030. We compare four different anthropogenic emissions forecasts: A1B and B1 from the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios and Current Legislation (CLE) and Maximum Feasible Reduction (MFR) from the International Institute for Applied Systems Analysis. The projections encompass a wide range of possible man-made emissions changes. The A1B, B1, and CLE forecasts all suggest large increases in surface O3 and sulfate baseline pollution at tropical and subtropical latitudes, especially over the Indian subcontinent, where the pollution increases may be as large as 100%. The ranges of annual mean regional ground level O-3 and sulfate changes across all scenarios are - 10 to + 30 ppbv and - 1200 to + 3000 pptv, respectively. Physical climate changes reduce future surface O3, but tend to increase ground level sulfate locally over North Africa because of an enhancement of aqueous-phase SO2 oxidation. For all examined future scenarios the combined sum of the CH4, O-3, and sulfate radiative forcings is positive, even for the MFR scenario, because of the large reduction in sulfate. For A1B the forcings are as much as half of that of the preindustrial to present- day forcing for each species. For MFR the sign of the forcing for each species is reversed with respect to the other scenarios. At 2030, global changes in climate-sensitive natural emissions of CH4 from wetlands, NOx from lightning, and dimethyl sulfide from the ocean appear to be small (< 5%). C1 Columbia Univ, NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Int Inst Appl Syst Anal, A-2361 Laxenburg, Austria. Argonne Natl Lab, Argonne, IL 60439 USA. RP Unger, N (reprint author), Columbia Univ, NASA, Goddard Inst Space Studies, 2880 Broadway,Suite 660, New York, NY 10025 USA. EM nunger@giss.nasa.gov RI Shindell, Drew/D-4636-2012; Magana, Felipe/B-6966-2013; Unger, Nadine/M-9360-2015; OI Streets, David/0000-0002-0223-1350 NR 49 TC 49 Z9 50 U1 0 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 JUN 27 PY 2006 VL 111 IS D12 AR D12313 DI 10.1029/2005JD006518 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 062IR UT WOS:000238938300004 ER PT J AU Zhai, Y Cummer, SA Farrell, WM AF Zhai, Y. Cummer, S. A. Farrell, W. M. TI Quasi-electrostatic field analysis and simulation of Martian and terrestrial dust devils SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID ELECTRIC FIELD; PROPAGATION; IONOSPHERE; STORMS; MARS AB [ 1] Recent experimental and modeling studies show that large quasi-static electric fields ( 2 - 20 kV/m) can be developed in a Martian or terrestrial dust devil as a result of contact electrification and charge separation of dust grains with different sizes and compositions. Electric discharging occurs when the maximum electric field reaches breakdown values ( similar to 20 kV/m on Mars and similar to 3 MV/m on Earth, at surface altitudes). We derive a maximum electric field in a dust devil and develop a two-dimensional (2-D) cylindrically symmetric finite element model for Martian and terrestrial dust devil simulations. Unlike previous models with unlimited field growth, the tribocharging process and the time evolution of the dust devil electric field are self-consistently limited in our model and the saturated maximum electric fields in our simulations are comparable to past measurements. We study the saturated maximum electric fields for dust storms of different size, atmosphere conductivity and time rate of tribocharging. We also discuss the 2-D cylindrical field structures surrounding a dust devil and the conductivity gradient effect to the field growth of large Martian dust storms. C1 Duke Univ, Dept Elect & Comp Engn, Durham, NC 27708 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Zhai, Y (reprint author), Duke Univ, Dept Elect & Comp Engn, Box 90291, Durham, NC 27708 USA. EM zhaiyh@ee.duke.edu; cummer@ee.duke.edu; farrell@faltraz.gsfc.nasa.gov RI Cummer, Steven/A-6118-2008; Farrell, William/I-4865-2013 OI Cummer, Steven/0000-0002-0002-0613; NR 19 TC 12 Z9 12 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-PLANET JI J. Geophys. Res.-Planets PD JUN 27 PY 2006 VL 111 IS E6 AR E06016 DI 10.1029/2005JE002618 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 062KA UT WOS:000238941800002 ER PT J AU Chen, JL Wilson, CR Seo, KW AF Chen, J. L. Wilson, C. R. Seo, K. -W. TI Optimized smoothing of gravity recovery and climate experiment (GRACE) time-variable gravity observations SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID ART.; VARIABILITY; SYSTEM AB [ 1] High-degree and high-order spherical harmonics of time-variable gravity fields observed by the Gravity Recovery and Climate Experiment ( GRACE) gravity mission are dominated by noise. We develop two smoothing methods that suppress these high-degree and high-order errors with results superior to more commonly used Gaussian smoothing. These optimized smoothing methods considerably improve signal-to-noise levels of GRACE terrestrial water storage estimates relative to residual signal and noise over the oceans and show significantly better spatial resolution and lower leakage error. On the basis of analysis using an advanced land surface model, the equivalent spatial resolution from these optimized smoothing estimates is about 500 km, compared to the roughly 800 1000 km Gaussian smoothing that is required to suppress high-degree noise in the GRACE fields. C1 Univ Texas, Ctr Space Res, Austin, TX 78759 USA. Univ Texas, Dept Geol Sci, Austin, TX 78759 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 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 NR 19 TC 35 Z9 40 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD JUN 27 PY 2006 VL 111 IS B6 AR B06408 DI 10.1029/2005JB004064 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 062KH UT WOS:000238942500002 ER PT J AU Gerhold, CH Clark, LR Dunn, MH Tweed, J AF Gerhold, CH Clark, LR Dunn, MH Tweed, J TI Investigation of acoustical shielding by a wedge-shaped airframe SO JOURNAL OF SOUND AND VIBRATION LA English DT Article ID RADIATION AB Experiments on a scale model of an advanced unconventional subsonic transport concept, the blended wing body (BWB), have demonstrated significant shielding of inlet-radiated noise. A computational model of the shielding mechanism has been developed using a combination of boundary integral equation method (BIEM) for source definition and equivalent source method (ESM) for scattering. In this way the sound fields with and without the airfoil can be estimated for comparison to experiment. An experimental test bed using a simplified wedge-shape airfoil and a broadband point noise source in a simulated nacelle has been developed for the purposes of verifying the analytical model and also to study the effect of engine nacelle placement on shielding. The analytic and experimental results are compared at 6300 and 8000 Hz. These frequencies correspond to approximately 125 and 160 Hz on the full-scale aircraft. Comparison between the experimental and analytic results is quite good, not only for the noise scattering by the airframe, but also for the total sound pressure in the far field. Many of the details of the sound field that the analytic model predicts are seen or indicated in the experiment, within the spatial resolution limitations of the experiment. Changing nacelle location produces comparable changes in noise shielding contours evaluated analytically and experimentally. (c) 2005 Elsevier Ltd. All rights reserved. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. Old Dominion Univ, Norfolk, VA USA. RP Gerhold, CH (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. EM carl.h.gerhold@nasa.gov NR 11 TC 3 Z9 3 U1 0 U2 1 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD JUN 27 PY 2006 VL 294 IS 1-2 BP 49 EP 63 DI 10.1016/j.jsv.2005.10.010 PG 15 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 051FE UT WOS:000238146200004 ER PT J AU Caldwell, JD Mastro, MA Hobart, KD Glembocki, OJ Eddy, CR Bassim, ND Holm, RT Henry, RL Twigg, ME Kub, F Neudeck, PG Trunek, AJ Powell, JA AF Caldwell, JD Mastro, MA Hobart, KD Glembocki, OJ Eddy, CR Bassim, ND Holm, RT Henry, RL Twigg, ME Kub, F Neudeck, PG Trunek, AJ Powell, JA TI Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas SO APPLIED PHYSICS LETTERS LA English DT Article ID MG-DOPED GAN; PHOTOLUMINESCENCE; SURFACES; FILMS AB We previously reported 100-fold reductions in III-N heterofilm threading dislocation density achieved via growth on top of (0001) 4H-SiC mesas completely free of atomic scale steps. This letter compares the electroluminescent (EL) output of GaN pn junctions grown on top of 4H-SiC mesas with and without such steps. An average of 49% enhancement of the ultraviolet luminescence (380 nm) was observed in step-free mesas over comparable "stepped" counterparts. Despite the intense EL from the step-free devices, significant leakage was observed through the periphery of the device, possibly due to the lack of GaN junction isolation processing. C1 USN, Res Lab, Washington, DC 20375 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. OAI, Cleveland, OH 44135 USA. Sest Inc, Cleveland, OH 44135 USA. RP Caldwell, JD (reprint author), USN, Res Lab, Washington, DC 20375 USA. EM joshua.cadwell@nrl.navy.mil RI Caldwell, Joshua/B-3253-2008 OI Caldwell, Joshua/0000-0003-0374-2168 NR 12 TC 14 Z9 14 U1 1 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 26 PY 2006 VL 88 IS 26 AR 263509 DI 10.1063/1.2218045 PG 3 WC Physics, Applied SC Physics GA 059EX UT WOS:000238717200085 ER PT J AU Oman, L Robock, A Stenchikov, GL Thordarson, T Koch, D Shindell, DT Gao, CC AF Oman, Luke Robock, Alan Stenchikov, Georgiy L. Thordarson, Thorvaldur Koch, Dorothy Shindell, Drew T. Gao, Chaochao TI Modeling the distribution of the volcanic aerosol cloud from the 1783-1784 Laki eruption SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPICAL STRATOSPHERIC RESERVOIR; PINATUBO ERUPTION; OPTICAL DEPTH; ICE CORE; ATMOSPHERIC IMPACT; GODDARD-INSTITUTE; SULFATE AEROSOL; SKAFTAR-FIRES; DRY FOG; CLIMATE AB We conducted simulations of the atmospheric transformation and transport of the emissions of the 1783-1784 Laki basaltic flood lava eruption (64.10 degrees N, 17.15 degrees W) using the NASA Goddard Institute for Space Studies modelE climate model coupled to a sulfur cycle chemistry model. The model simulations successfully reproduced the aerosol clouds of the 1912 Katmai and 1991 Mount Pinatubo eruptions, giving us confidence in the Laki simulations. Simulations of the Laki eruption produce peak zonal mean sulfate ( SO4) concentrations of over 70 ppbv during August and into September 1783 in the upper troposphere and lower stratosphere at high latitudes. While the majority of the sulfate aerosol was removed during the fall and early winter, a significant aerosol perturbation remained into 1784. The peak SO2 gas loading was just over 37 megatons (Mt) in late June with the sulfate loading peaking in late August 1783 at 60 Mt over the average of 3 runs. This yielded a peak sulfate aerosol (75% H2SO4, 25% H2O) loading of over 80 Mt with the total aerosol produced during the entire eruption being about 165 Mt. The resulting sulfate deposition compares well with ice cores taken across Greenland. The top of atmosphere net radiative forcing peaks at -27 W/m(2) over the high latitudes during late summer 1783 and produces a global mean forcing of -4 W/m(2). The model results confirm that Northern Hemisphere high-latitude volcanic eruptions produce aerosols that remain mostly confined north of 30 degrees N latitude. C1 Rutgers State Univ, Dept Environm Sci, New Brunswick, NJ 08901 USA. Univ Hawaii, Dept Geol & Geophys, Honolulu, HI 96822 USA. Univ Iceland, Inst Earth Sci, Reykjavik, Iceland. Univ Edinburgh, Sch Geosci, Grant Inst Geol, Edinburgh EH9 3JW, Midlothian, Scotland. Columbia Univ, Ctr Climat Syst Res, New York, NY USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Oman, L (reprint author), Rutgers State Univ, Dept Environm Sci, 14 Coll Farm Rd, New Brunswick, NJ 08901 USA. EM oman@cep.rutgers.edu RI Oman, Luke/C-2778-2009; Gao, Chaochao/G-9154-2011; Shindell, Drew/D-4636-2012; Thordarson, Thorvaldur/A-8990-2013; Georgiy, Stenchikov/J-8569-2013; Thordarson, Thorvaldur/M-2422-2015; Robock, Alan/B-6385-2016; OI Oman, Luke/0000-0002-5487-2598; Thordarson, Thorvaldur/0000-0003-4011-7185; Robock, Alan/0000-0002-6319-5656 NR 56 TC 60 Z9 62 U1 1 U2 19 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 JUN 24 PY 2006 VL 111 IS D12 AR D12209 DI 10.1029/2005JD006899 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 057MF UT WOS:000238599200002 ER PT J AU Farrell, WM Goldberg, RA Blakeslee, RJ Desch, MD Mach, DM AF Farrell, WM Goldberg, RA Blakeslee, RJ Desch, MD Mach, DM TI Radiation impedance over a thunderstorm SO RADIO SCIENCE LA English DT Article ID FIELDS AB [ 1] In the summer of 2002 the Altus Cumulus Electrification Study obtained radiated Poynting flux measurements in the near vicinity of lightning discharge events. These measurements not only allow a determination of radiated power but also allow a calculation of the radiation impedance above a thunderstorm when the thunderstorm was acting as an antenna. This impedance is significant since it defines the level of displacement currents propagating into the middle atmosphere and, as applications demonstrate, is a critical quantity in understanding the relationship between power and displacement current in the near vicinity of a thunderstorm. We find that the radiation impedance of the thunderstorm is surprisingly low in the VLF and varies inversely with frequency consistent with a capacitive-like coupling from the thunderstorm to middle atmosphere. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. NASA, George C Marshall Space Flight Ctr, Global Hydrol & Climate Ctr, Huntsville, AL 35805 USA. RP Farrell, WM (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, MC 695, Greenbelt, MD 20771 USA. EM william.farrell@gsfc.nasa.gov RI Goldberg, Richard /E-1881-2012; Farrell, William/I-4865-2013 NR 12 TC 3 Z9 3 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 JUN 24 PY 2006 VL 41 IS 3 AR RS3008 DI 10.1029/2004RS003217 PG 7 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 057OE UT WOS:000238604300001 ER PT J AU Schwartz, SJ Sibeck, D Wilber, M Meziane, K Horbury, TS AF Schwartz, SJ Sibeck, D Wilber, M Meziane, K Horbury, TS TI Kinetic aspects of foreshock cavities SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID HOT FLOW ANOMALIES; EARTHS BOW SHOCK; DIAMAGNETIC CAVITIES; SOLAR-WIND; CLUSTER AB We have investigated the kinetic signatures within, and at the edges of, a foreshock cavity. Such cavities are believed to be formed when an isolated collection of interplanetary magnetic field lines connect to quasi-parallel regions of the Earth's bow shock, allowing energetic ions to flow upstream and excavate a local cavity. Observations by the Cluster spacecraft show precisely this configuration. The suprathermal ions can be seen just outside the edges of the cavity within a restricted range of gyrophases, consistent with their gyromotion tangential to the layer containing the cavity. Foreshock cavities, if sufficiently common, may play significant roles in triggering magnetospheric events. Thus our confirmation of their relatively simple formation mechanism lends support to their inferred frequency. C1 Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BW, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Space Sci Lab, Berkeley, CA 94620 USA. Univ New Brunswick, Dept Phys, Fredericton, NB E3B 5A3, Canada. RP Schwartz, SJ (reprint author), Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BW, England. EM s.schwartz@imperial.ac.uk; dsibeck@pop600.gsfc.nasa.gov; wilber@ssl.berkeley.edu; karim@unb.ca; t.horbury@imperial.ac.uk RI Sibeck, David/D-4424-2012 NR 15 TC 13 Z9 13 U1 1 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 JUN 23 PY 2006 VL 33 IS 12 AR L12103 DI 10.1029/2005GL025612 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 057LO UT WOS:000238597500001 ER PT J AU Cane, HV Mewaldt, RA Cohen, CMS von Rosenvinge, TT AF Cane, H. V. Mewaldt, R. A. Cohen, C. M. S. von Rosenvinge, T. T. TI Role of flares and shocks in determining solar energetic particle abundances SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ADVANCED COMPOSITION EXPLORER; CORONAL MASS EJECTIONS; COSMIC-RAY DECREASES; INTERPLANETARY SHOCKS; EVENTS; WIND; IONS; ACCELERATION; ENERGIES; TOPOLOGY AB [ 1] We examine solar energetic particle (SEP) event-averaged abundances of Fe relative to O and intensity versus time profiles at energies above 25 MeV/ nucleon using the SIS instrument on ACE. These data are compared with solar wind conditions during each event and with estimates of the strength of the associated shock based on average travel times to 1 AU. We find that the majority of events with an Fe to O abundance ratio greater than two times the average 5 - 12 MeV/nuc value for large SEP events (0.134) occur in the western hemisphere. Furthermore, in most of these Fe-rich events the profiles peak within 12 hours of the associated flare, suggesting that some of the observed interplanetary particles are accelerated in these flares. The vast majority of events with Fe/O below 0.134 are influenced by interplanetary shock acceleration. We suggest that variations in elemental composition in SEP events mainly arise from the combination of flare particles and shock acceleration of these particles and/or the ambient medium. C1 NASA, Goddard Space Flight Ctr, Astroparticle Phys Lab, Greenbelt, MD 20771 USA. Univ Tasmania, Sch Math & Phys, Hobart, Tas, Australia. CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. RP Cane, HV (reprint author), NASA, Goddard Space Flight Ctr, Astroparticle Phys Lab, Code 661, Greenbelt, MD 20771 USA. EM hilary.cane@utas.edu.au; rmewaldt@srl.caltech.edu; cohen@srl.caltech.edu; tycho@milkyway.gsfc.nasa.gov NR 30 TC 62 Z9 62 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-SPACE JI J. Geophys. Res-Space Phys. PD JUN 23 PY 2006 VL 111 IS A6 AR A06S90 DI 10.1029/2005JA011071 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 057NW UT WOS:000238603500001 ER PT J AU Burns, JA Cuzzi, JN AF Burns, JA Cuzzi, JN TI Our local astrophysical laboratory SO SCIENCE LA English DT Editorial Material C1 Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Cornell Univ, Dept Theoret & Appl Mech, Ithaca, NY 14853 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Burns, JA (reprint author), Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. EM jab16@cornell.edu NR 10 TC 8 Z9 8 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 JUN 23 PY 2006 VL 312 IS 5781 BP 1753 EP 1755 DI 10.1126/science.1114856 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 055LS UT WOS:000238452800041 PM 16794067 ER PT J AU Espley, JR Delory, GT Cloutier, PA AF Espley, JR Delory, GT Cloutier, PA TI Initial observations of low-frequency magnetic fluctuations in the Martian ionosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID MARS GLOBAL SURVEYOR; SOLAR-WIND; PLASMA ENVIRONMENT; FIELD; WAVES; BOUNDARY AB [ 1] Using Mars Global Surveyor magnetometer/electron reflectometer measurements, we report initial observations of low-frequency magnetic fluctuations in the Martian ionosphere. We find that the waves have dominant frequencies between 0.01 and 1 Hz and are observed both close to and far from crustal magnetic fields. These waves are possibly related to magnetosonic perturbations produced at higher altitudes in the Mars - solar wind interaction. These fluctuations have implications for understanding the physics of the ionosphere and potentially could also help characterize electromagnetically active atmospheric phenomena such as dust devils and dust storms. The presence of such fluctuations in the Martian ionosphere is also an indication of the plausibility of using low-frequency electromagnetic methods, such as the magnetotelluric technique, to probe the deep subsurface. One potential result of such an investigation would be the identification of any subsurface liquid water that might be present within the first several hundred meters to the first few kilometers of the subsurface. C1 Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP Espley, JR (reprint author), NASA, Goddard Space Flight Ctr, MS 695-0, Greenbelt, MD 20701 USA. EM jared.espley@gsfc.nasa.gov; gdelory@ssl.berkeley.edu; pac@spacibm.rice.edu RI Espley, Jared/I-5118-2013 OI Espley, Jared/0000-0002-6371-9683 NR 28 TC 3 Z9 3 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 JUN 22 PY 2006 VL 111 IS E6 AR E06S22 DI 10.1029/2005JE002587 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 057MT UT WOS:000238600600002 ER PT J AU Lara, A Gopalswamy, N Xie, H Mendoza-Torres, E Perez-Eriquez, R Michalek, G AF Lara, A Gopalswamy, N Xie, H Mendoza-Torres, E Perez-Eriquez, R Michalek, G TI Are halo coronal mass ejections special events? SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID WATER MASERS; SHOCK-WAVES; LARGE-ANGLE; H2O MASERS; II BURSTS; NEAR-SUN; CMES; W49N; EMISSION; SPACE AB [ 1] We revisited the properties of wide coronal mass ejections (CMEs) called halo CMEs. Using the large LASCO/SOHO CMEs data set, from 1996 to 2004, we examined the statistical properties of ( partial and full) halo CMEs and compare with the same properties of "normal'' width ( lower than 120 degrees) CMEs. We found that halo CMEs have different properties than "normal'' CMEs, which cannot be explained merely by the current geometric interpretation that they are seen as halos because they are traveling in the Sun Earth direction. We found that the CME width distribution is formed by, at least, three different populations: Two gaussians: a narrow and a medium distribution centered at similar to 17 degrees and similar to 38 degrees, respectively; the narrow population most likely corresponds to the "true'' observed widths, whereas the medium width population is the product of projection effects. The third distribution corresponds to wider CMEs (80 degrees< W < 210 degrees) which behaves as a power law. Partial and full halo CMEs wider than these do not follow any particular distribution. This lack of regularity may be due to the small number of such events. In particular, we found ( and test by a statistical approach) that the number of observed full halo CMEs is lower than expected. The CME speed follows a log- normal distribution, except for the very low speed CME population, which follows a gaussian distribution centered at similar to 100 km/s and is probably due to projection effects. When the CMEs are divided by width into nonhalo, partial halo, and full halo, we found that the peaks of the distributions are shifted toward higher speeds, similar to 300, similar to 400 and similar to 600 km/s for nonhalo, partial halo, and full halo CMEs, respectively. This confirms that halo CMEs tend to be high speed CMEs. The acceleration of full halo CMEs tends to be more negative compared with nonhalo and partial halo CMEs. We introduce a new observational CME parameter: The final observed distance (FOD), i.e., the highest point within the coronograph field of view where a CME can be distinguished from the background. In other words, the highest CME altitude measured. The FOD for nonhalo CMEs decreases exponentially from similar to 5 to similar to 30 R-. in the LASCO field of view. On the other hand, the FOD of halo CMEs increase with distance. This means that it is more likely to see halo CMEs at large distances ( from the Sun) than nonhalo CMEs. These halo CME properties may be explained if the white light wide enhancements ( or halo) seen by coronographs correspond to a combination of an expanding ( shock) wave which disturbs and/or compresses the ambient material and the CME material itself. C1 Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Catholic Univ Amer, Washington, DC 20064 USA. Inst Nacl Astrofis Opt & Elect, Tonantzintla 72840, Mexico. Univ Nacl Autonoma Mexico, Ctr Geociencias, Juriquilla 76001, Queretaro, Mexico. Jagiellonian Univ, Astron Observ, PL-30244 Krakow, Poland. RP Lara, A (reprint author), Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico. EM alara@geofisica.unam.mx RI Gopalswamy, Nat/D-3659-2012; OI Lara, Alejandro/0000-0001-6336-5291 NR 40 TC 15 Z9 15 U1 0 U2 6 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 JUN 22 PY 2006 VL 111 IS A6 AR A06107 DI 10.1029/2005JA011431 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 057NT UT WOS:000238603200004 ER PT J AU Pollack, SE Stebbins, RT AF Pollack, SE Stebbins, RT TI Demonstration of the zero-crossing phasemeter with a LISA test-bed interferometer SO CLASSICAL AND QUANTUM GRAVITY LA English DT Article AB The laser interferometer space antenna (LISA) is being designed to detect and study in detail gravitational waves from sources throughout the Universe such as massive black hole binaries. The conceptual formulation of the LISA space-borne gravitational wave detector is now well developed. The interferometric measurements between the sciencecraft remain one of the most important technological and scientific design areas for the mission. Our work has concentrated on developing the interferometric technologies to create a LISA-like optical signal and to measure the phase of that signal using commercially available instruments. One of the most important goals of this research is to demonstrate the LISA phase timing and phase reconstruction for a LISA-like fringe signal, in the case of a high fringe rate and a low signal level. We present current results of a test-bed interferometer designed to produce an optical LISA-like fringe signal previously discussed in Jennrich O, Stebbins R T, Bender P L and Pollack S (2001 Class. Quantum Grav. 18 4159 - 64) and Pollack S E, Jennrich O, Stebbins R T and Bender P (2003 Class. Quantum Grav. 20 S291 - 00). C1 Univ Colorado, JILA, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pollack, SE (reprint author), Univ Washington, CENPA Nucl Phys Lab, Seattle, WA 98195 USA. EM scott.pollack@colorado.edu RI Stebbins, Robin/G-5009-2013 NR 9 TC 6 Z9 6 U1 1 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0264-9381 J9 CLASSICAL QUANT GRAV JI Class. Quantum Gravity PD JUN 21 PY 2006 VL 23 IS 12 BP 4189 EP 4200 DI 10.1088/0264-9381/23/12/014 PG 12 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 050YH UT WOS:000238126300014 ER PT J AU Pollack, SE Stebbins, RT AF Pollack, SE Stebbins, RT TI A demonstration of LISA laser communication SO CLASSICAL AND QUANTUM GRAVITY LA English DT Article ID LOCKING; ARM AB Over the past few years, questions have been raised concerning the use of laser communications links between sciencecraft to transmit phase information crucial to the reduction of laser frequency noise in the LISA science measurement. The concern is that applying medium frequency phase modulations to the laser carrier could compromise the phase stability of the LISA fringe signal. We have modified the table-top interferometer presented in Pollack and Stebbins (2006 Demonstration of the zero-crossing phasemeter with a LISA test-bed interferometer Class. Quantum Grav.) by applying phase modulations to the laser beams in order to evaluate the effects of such modulations on the LISA science fringe signal. We have demonstrated that the phase resolution of the science signal is not degraded by the presence of medium frequency phase modulations. C1 Univ Colorado, JILA, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pollack, SE (reprint author), Univ Washington, CENPA, Nucl Phys Lab, Seattle, WA 98195 USA. EM scott.pollack@colorado.edu RI Stebbins, Robin/G-5009-2013 NR 13 TC 6 Z9 6 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0264-9381 J9 CLASSICAL QUANT GRAV JI Class. Quantum Gravity PD JUN 21 PY 2006 VL 23 IS 12 BP 4201 EP 4213 DI 10.1088/0264-9381/23/12/015 PG 13 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 050YH UT WOS:000238126300015 ER PT J AU LeGrande, AN Schmidt, GA AF LeGrande, AN Schmidt, GA TI Global gridded data set of the oxygen isotopic composition in seawater SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OCEAN; WATER; ICE AB We present a new 3-dimensional 1 degrees x 1 degrees gridded data set for the annual mean seawater oxygen isotope ratio (delta O-18) to use in oceanographic and paleoceanographic applications. It is constructed from a large set of observations made over the last 50 years combined with estimates from regional delta O-18 to salinity relationships in areas of sparse data. We use ocean fronts and water mass tracer concentrations to help define distinct water masses over which consistent local relationships are valid. The resulting data set compares well to the GEOSECS data (where available); however, in certain regions, particularly where sea ice is present, significant seasonality may bias the results. As an example application of this data set, we use the resulting surface delta O-18 as a boundary condition for isotope-enabled GISS ModelE to yield a more realistic comparison to the isotopic composition of precipitation data, thus quantifying the 'source effect' of delta O-18 on the isotopic composition of precipitation. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Ctr Climat Syst Res, New York, NY 10025 USA. RP LeGrande, AN (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM legrande@giss.nasa.gov 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 19 TC 274 Z9 278 U1 4 U2 60 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 JUN 21 PY 2006 VL 33 IS 12 AR L12604 DI 10.1029/2006GL026011 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 057LL UT WOS:000238597200002 ER PT J AU Sanchez, BV Rowlands, DD Haberle, RM AF Sanchez, BV Rowlands, DD Haberle, RM TI Variations of Mars gravitational field based on the NASA/Ames general circulation model SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID GRAVITY-FIELD; ATMOSPHERE; ROTATION; EXCHANGE; CAPS AB [ 1] The NASA/Ames general circulation model (GCM) has been used to compute time series for the variations in the Stokes coefficients expressing Mars' gravitational field in spherical harmonics. The sources of the variations are changes in the mass distribution of the atmosphere and changes in the planetary ice caps. The latter are due mainly to the condensation and sublimation of CO2 on the surface of Mars. Variations were obtained for coefficients up to degree and order 40, which is the maximum allowed by the spatial definition of the model. The time series covered a period of a full Martian year of 669 sols with a time step of 1.5 hours. The time series were analyzed by means of fast Fourier transforms. The largest variations occur in C-10 corresponding to a 27.5-mm displacement of the center of mass in the z-direction. Other geoidal variations are C-30 (17.7 mm), C-20 (11.4 mm) and C-50 (10.0 mm). The main harmonics are annual, (1/2)-annual and (1/3)-annual. Most of the power is due to ice caps variations. Mars Global Surveyor trajectory runs with and without the above orbit perturbations yield RMS differences in total position which range between 4.44 and 17.39 m over a 7-day arc, depending on the season. A 7-day simulated tracking data least squares solution in which some level of the perturbations is absorbed into initial state parameters yields RMS differences between 0.35 and 0.78 m in total position. C1 NASA, Planetary Geodynam Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Space Geodesy Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Div Space Sci, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Sanchez, BV (reprint author), NASA, Planetary Geodynam Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM braulio.v.sanchez@nasa.gov; david.d.rowlands@nasa.gov; robert.m.haberle@nasa.gov RI Rowlands, David/D-2751-2012; Sanchez, Braulio/I-5952-2013 NR 21 TC 6 Z9 7 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 JUN 21 PY 2006 VL 111 IS E6 AR E06010 DI 10.1029/2005JE002442 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 057MR UT WOS:000238600400001 ER PT J AU Cayon, L Banday, AJ Jaffe, T Eriksen, HK Hansen, FK Gorski, KM Jin, J AF Cayon, L Banday, AJ Jaffe, T Eriksen, HK Hansen, FK Gorski, KM Jin, J TI No Higher criticism of the bianchi-corrected Wilkinson microwave anisotropy probe data SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE methods : statistical; cosmic microwave background; cosmology : miscellaneous ID NON-GAUSSIANITY; WMAP DATA; 1ST-YEAR DATA; SPHERICAL WAVELETS; ISOTROPY AB Higher Criticism (HC) has been proposed by Donoho & Jin as an effective statistic to detect deviations from Gaussianity. Motivated by the success of the Bianchi VIIh model in addressing many of the anomalies observed in the Wilkinson Microwave Anisotropy Probe (WMAP) data (Jaffe et al.), we present calculations in real and in wavelet space of the HC statistic of the Bianchi-corrected WMAP first-year data. At the wavelet scale of 5 degrees, the HC of the WMAP map drops from a value above the 99 per cent confidence level (c.l.) to a value below the 68 per cent CL when corrected by the Bianchi template. An important property of the HC statistic is its ability to locate the pixels that account for the deviation from Gaussianity. The analysis of the uncorrected WMAP data pointed to a cold spot in the Southern hemisphere, centred at l similar to 209 degrees, b similar to -57 degrees. The HC of the Bianchi-corrected map indicates that this spot remains prominent, albeit at a level completely consistent with Gaussian statistics. Consequently, it is debatable how much emphasis should be placed on this residual feature, but we consider the effect of modestly increasing the scaling of the template. A factor of only 1.2 renders the spot indistinguishable from the background level, with no noticeable impact on the results published in Jaffe et al. for the low-l anomalies, large-scale power asymmetry or wavelet kurtosis. A trivial interpretation would be that the Bianchi template may require a small enhancement of power on scales corresponding to the wavelet scale of 5 degrees. C1 Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. Max Planck Inst Astrophys, D-85741 Garching, Germany. Univ Oslo, Inst Theoret Astrophys, N-0315 Oslo, Norway. Univ Oslo, Dept Math Appl, N-0315 Oslo, Norway. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Pasadena, CA 91125 USA. Purdue Univ, Dept Stat, W Lafayette, IN 47907 USA. RP Cayon, L (reprint author), Purdue Univ, Dept Phys, 525 Northwestern Ave, W Lafayette, IN 47907 USA. EM cayon@physics.purdue.edu NR 32 TC 19 Z9 19 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 JUN 21 PY 2006 VL 369 IS 2 BP 598 EP 602 DI 10.1111/j.1365-2966.2006.10381.x PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 050QW UT WOS:000238104000005 ER PT J AU Vassiliadis, D AF Vassiliadis, Dimitris TI Systems theory for geospace plasma dynamics SO REVIEWS OF GEOPHYSICS LA English DT Review ID DATA-DERIVED ANALOGS; DRIVEN MAGNETOSPHERE-IONOSPHERE; INTERPLANETARY MAGNETIC-FIELD; AURORAL GEOMAGNETIC-ACTIVITY; RADIATION BELT ELECTRONS; NEURAL-NETWORK MODEL; TIME-SERIES DATA; SOLAR-WIND; NONLINEAR DYNAMICS; AE-INDEX AB [ 1] This is a tutorial review on systems theory and its applications to space plasma physics and, more broadly, on geophysics. With its basis on the state representation of a plasma the theory is widely applicable, but it is of particular interest for dynamical, nonlinear, or out-of-equilibrium regimes that cannot be represented by traditional microscopic modeling. Two distinct, but closely related, branches of the theory are applied when the plasma dynamics is traced to first principles and when it needs to be derived from experimental data. A framework of modeling methods is presented in order of increasing complexity: enumeration of the effective degrees of freedom, measurement of the linear dynamics and stability, and generalization to their nonlinear counterparts. The relation between symmetries in the plasma system and modes in its structure and response is discussed. Signal processing methods are presented, illustrated by examples, and their relative merits and limitations are discussed. The dynamical framework provides a new approach alongside the traditional perturbative and statistical-mechanical methodologies and is directly relevant to the development of space weather applications. C1 NASA, Sarissa Technol, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Vassiliadis, D (reprint author), NASA, Sarissa Technol, Goddard Space Flight Ctr, Code 612-2,Bldg 21,Room 265, Greenbelt, MD 20771 USA. EM vassi@electra.gsfc.nasa.gov NR 217 TC 25 Z9 25 U1 1 U2 10 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 JUN 21 PY 2006 VL 44 IS 2 AR RG2002 DI 10.1029/2004RG000161 PG 39 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 057OM UT WOS:000238605100001 ER PT J AU Liu, ZY Hunt, W Vaughan, M Hostetler, C McGill, M Powell, K Winker, D Hu, YX AF Liu, Zhaoyan Hunt, William Vaughan, Mark Hostetler, Chris McGill, Matthew Powell, Kathleen Winker, David Hu, Yongxiang TI Estimating random errors due to shot noise in backscatter lidar observations SO APPLIED OPTICS LA English DT Article AB We discuss the estimation of random errors due to shot noise in backscatter lidar observations that use either photomultiplier tube (PMT) or avalanche photodiode (APD) detectors. The statistical characteristics of photodetection are reviewed, and photon count distributions of solar background signals and laser backscatter signals are examined using airborne lidar observations at 532 nm using a photon-counting mode APD. Both distributions appear to be Poisson, indicating that the arrival at the photodetector of photons for these signals is a Poisson stochastic process. For Poisson-distributed signals, a proportional, one-to-one relationship is known to exist between the mean of a distribution and its variance. Although the multiplied photocurrent no longer follows a strict Poisson distribution in analog-mode APD, and PMT detectors, the proportionality still exists between the mean and the variance of the multiplied photocurrent. We make use of this relationship by introducing the noise scale factor (NSF), which quantifies the constant of proportionality that exists between the root mean square of the random noise in a measurement and the square root of the mean signal. Using the NSF to estimate random errors in lidar measurements due to shot noise provides a significant advantage over the conventional error estimation techniques, in that with the NSF, uncertainties can be reliably calculated from or for a single data sample. Methods for evaluating the NSF are presented. Algorithms to compute the NSF are developed for the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations lidar and tested using data from the Lidar In-space Technology Experiment. (c) 2006 Optical Society of America. C1 Natl Inst Aerosp, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Sci Applicat Int Corp, Hampton, VA 23681 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Liu, ZY (reprint author), Natl Inst Aerosp, 100 Explorat Way, Hampton, VA 23666 USA. EM zliu@nianet.org RI Liu, Zhaoyan/A-9604-2009; Liu, Zhaoyan/B-1783-2010; McGill, Matthew/D-8176-2012; Hu, Yongxiang/K-4426-2012 OI Liu, Zhaoyan/0000-0003-4996-5738; NR 14 TC 42 Z9 48 U1 2 U2 15 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUN 20 PY 2006 VL 45 IS 18 BP 4437 EP 4447 DI 10.1364/AO.45.004437 PG 11 WC Optics SC Optics GA 054HE UT WOS:000238366600027 PM 16778954 ER PT J AU Mishchenko, MI Rosenbush, VK Kiselev, NN AF Mishchenko, Michael I. Rosenbush, Vera K. Kiselev, Nikolai N. TI Weak localization of electromagnetic waves and opposition phenomena exhibited by high-albedo atmosphereless solar system objects SO APPLIED OPTICS LA English DT Article ID GALILEAN SATELLITES; OPTICAL POLARIMETRY; MULTIPLE-SCATTERING; SATURNS RINGS; COHERENT BACKSCATTERING; RANDOM-MEDIA; POLARIZATION; PHOTOMETRY; JUPITER; LIGHT AB The totality of new and previous optical observations of a class of high-albedo solar system objects at small phase angles reveals a unique combination of extremely narrow brightness and polarization features centered at exactly the opposition. The specific morphological parameters of these features provide an almost unequivocal evidence that they are caused by the renowned effect of coherent backscattering. (c) 2006 Optical Society of America. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Natl Acad Sci Ukraine, Main Astron Observ, UA-03680 Kiev, Ukraine. Kharkov Natl Univ, Inst Astron, UA-61022 Kharkov, Ukraine. RP Mishchenko, MI (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM mmishchenko@giss.nasa.gov; rosevera@mao.kiev.ua; kiselev@mao.kiev.ua RI Mishchenko, Michael/D-4426-2012 NR 40 TC 37 Z9 37 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUN 20 PY 2006 VL 45 IS 18 BP 4459 EP 4463 DI 10.1364/AO.45.004459 PG 5 WC Optics SC Optics GA 054HE UT WOS:000238366600029 PM 16778956 ER PT J AU Jaffe, TR Hervik, S Banday, AJ Gorski, KM AF Jaffe, TR Hervik, S Banday, AJ Gorski, KM TI On the viability of Bianchi type VIIh models with dark energy SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations ID PROBE WMAP OBSERVATIONS; HUBBLE-SPACE-TELESCOPE; COSMOLOGICAL PARAMETERS; NON-GAUSSIANITY; POWER-SPECTRUM; 1ST-YEAR DATA; ANISOTROPY; ISOTROPY; CONSTRAINTS; SUPERNOVAE AB We generalize the predictions for the cosmic microwave background (CMB) anisotropy patterns arising in Bianchi type VIIh universes to include a dark energy component. We consider these models in light of the result of Jaffe and collaborators in which a correlation was found on large angular scales between the WMAP data and the anisotropy structure in a low-density Bianchi universe. We find that by including a term Omega(Lambda) > 0, the same best-fit anisotropy pattern is reproduced by several combinations of cosmological parameters. This subset of models can then be further constrained by current observations that limit the values of various cosmological parameters. In particular, we consider the so-called geometric degeneracy in these parameters imposed by the peak structure of the WMAP data themselves. Apparently, despite the additional freedom allowed by the dark energy component, the modified Bianchi models are ruled out at high significance. C1 Max Planck Inst Astrophys, D-85741 Garching, Germany. Dalhousie Univ, Dept Math & Stat, Halifax, NS B3H 3J5, Canada. Jet Prop Lab, Pasadena, CA 91109 USA. Univ Warsaw Observ, PL-00478 Warsaw, Poland. RP Jaffe, TR (reprint author), Max Planck Inst Astrophys, Karl Schwarzschild Str 1,Postfach 1317, D-85741 Garching, Germany. EM tjaffe@mpa-garching.mpg.de; herviks@mathstat.dal.ca; banday@mpa-garching.mpg.de; krzysztof.m.gorski@jpl.nasa.gov NR 36 TC 53 Z9 53 U1 0 U2 2 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 JUN 20 PY 2006 VL 644 IS 2 BP 701 EP 708 DI 10.1086/503893 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XS UT WOS:000238340100005 ER PT J AU Gallagher, SC Brandt, WN Chartas, G Priddey, R Garmire, GP Sambruna, RM AF Gallagher, SC Brandt, WN Chartas, G Priddey, R Garmire, GP Sambruna, RM TI An exploratory Chandra survey of a well-defined sample of 35 large bright quasar survey broad absorption line quasars SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; quasars : absorption lines; quasars : general; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; DIGITAL SKY SURVEY; SOFT-X-RAY; RADIO-QUIET QUASARS; XMM-NEWTON SPECTROSCOPY; DRIVEN DISK WINDS; STELLAR OBJECTS; EMISSION-LINE; ULTRAVIOLET-ABSORPTION; STATISTICAL-METHODS AB We present 4-7 ks Chandra observations of 35 broad absorption line (BAL) quasars from the Large Bright Quasar Survey, the largest sample of sensitive, 0.5-8.0 keV X-ray observations of this class of quasars to date. The limited ranges in both redshift (z = 1.42-2.90) and ultraviolet luminosity (a factor of approximate to 12) of the sample alsomake it relatively uniform. Of 35 targets, 27 are detected for a detection fraction of 77%, and we confirm previous studies that find BAL quasars to be generally X-ray-weak. Five of the eight nondetections are known low-ionization BAL quasars, confirming reports of extreme X- ray weakness in this subset (similar to 10% of optically selected BAL quasars). Those BAL quasars with the hardest X- ray spectra are also the X- ray weakest, consistent with the interpretation that intrinsic absorption is the primary cause of X- ray weakness in this class of quasars as a whole. Furthermore, the observed trend is not consistent with simple neutral absorption, supporting findings from spectroscopic observations of individual targets that BAL quasars typically exhibit complex X- ray absorption (e.g., partially covering or ionized absorbers). Assuming normal quasar X- ray continua and using the hard-band (observed-frame 2-8 keV) X-ray flux to ``correct'' for the effects of intrinsic absorption at softer energies increases the relative X-ray to optical flux ratios to much closer to the range for normal quasars, further indicating that typically neither are high-ionization BAL quasars intrinsically X-ray-weak, nor do they suffer from Compton-thick absorption. In general, we find no evidence for correlations between X-ray weakness and ultraviolet absorption-line properties, with the exception of a likely correlation between the maximum outflow velocity of C IV absorption and the magnitude of X-ray weakness. We discuss the implications of our results for disk-wind models of BAL outflows in quasars. C1 Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Univ Hertfordshire, Ctr Astrophys Res, Hatfield AL10 9AB, Herts, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gallagher, SC (reprint author), Univ Calif Los Angeles, Dept Phys & Astron, 430 Portola Plaza,Box 95147, Los Angeles, CA 90095 USA. EM sgall@astro.ucla.edu; niel@astro.psu.edu; chartas@astro.psu.edu; priddey@star.herts.ac.uk; garmire@astro.psu.edu; rms@milkyway.gsfc.nasa.gov RI Brandt, William/N-2844-2015 OI Brandt, William/0000-0002-0167-2453 NR 72 TC 115 Z9 115 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 JUN 20 PY 2006 VL 644 IS 2 BP 709 EP 724 DI 10.1086/503762 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XS UT WOS:000238340100006 ER PT J AU Dye, S Eales, SA Ashby, MLN Huang, JS Webb, TMA Barmby, P Lilly, S Brodwin, M McCracken, H Egami, E Fazio, GG AF Dye, S. Eales, S. A. Ashby, M. L. N. Huang, J. -S. Webb, T. M. A. Barmby, P. Lilly, S. Brodwin, M. McCracken, H. Egami, E. Fazio, G. G. TI An investigation of the submillimeter background radiation using SCUBA and Spitzer SO ASTROPHYSICAL JOURNAL LA English DT Article DE diffuse radiation; infrared : galaxies; submillimeter ID HUBBLE-DEEP-FIELD; 14 HOUR FIELD; FRANCE REDSHIFT SURVEY; LYMAN BREAK GALAXIES; ARRAY CAMERA IRAC; SPACE-TELESCOPE; SOURCE IDENTIFICATIONS; STARBURST GALAXIES; SCUBA-8-MJY SURVEY; 3-HOUR FIELD AB We investigate the redshift dependence of the contribution to the extragalactic far-infrared/submillimeter background from galaxies detected by the Spitzer Space Telescope at 8 and 24 mu m. Using seven-band optical to mid-infrared photometry, we estimate photometric redshifts for the Spitzer sources that appear to be mostly L-* galaxies at a median redshift of z = 1.0. These sources, extracted from deep 8 and 24 mu m mosaics of the CUDSS 14 hour field with 5 sigma limits of 5.8 and 70 mu Jy, respectively, exhibit significant 850 and 450 mu m emission as observed by SCUBA. At 850 mu m, after removing >= 4 sigma sources and those securely identified in our companion cross-matching paper, we measure stacked flux at the significance level of 4.4 and 2.9 sigma from the full 8 and 24 mu m galaxy catalog, respectively. At 450 mu m, flux is detected from all 8 mu m galaxies at the level of 3.5 sigma, while there is no significant emission from the 24 mu m galaxies. We find that the 850 mu m flux is emitted almost exclusively at z greater than or similar to 1.3 from the Spitzer sources with 0.44 mJy (4.7 sigma) per 8 mu m source, and 0.51 mJy (2.8 sigma) per 24 mu m source. This corresponds to a contribution of (16 +/- 3)% toward the 850 mu m extragalactic background from the 8 mu m sources, and (5.0 +/- 1.8)% from the 24 mu m sources. At 450 mu m, only the 8 mu m sources within the redshift interval 1 < z < 2 exhibit significant emission with an average flux per source of 3.35 mJy (3.0 sigma). This is a contribution of (37 +/- 12)% to the 450 mu m background. C1 Cardiff Univ, Sch Phys & Astron, Cardiff CF24 3YB, Wales. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Sterrewacht Leiden, NL-233 CA Leiden, Netherlands. Swiss Fed Inst Technol, Inst Astron, CH-8093 Zurich, Switzerland. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Inst Astrophys, F-75014 Paris, France. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Dye, S (reprint author), Cardiff Univ, Sch Phys & Astron, 5 The Parade, Cardiff CF24 3YB, Wales. RI Barmby, Pauline/I-7194-2016; OI Barmby, Pauline/0000-0003-2767-0090; Dye, Simon/0000-0002-1318-8343 NR 46 TC 10 Z9 10 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 JUN 20 PY 2006 VL 644 IS 2 BP 769 EP 777 DI 10.1086/503863 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XS UT WOS:000238340100012 ER PT J AU Ashby, MLN Dye, S Huang, JS Eales, S Willner, SP Webb, TMA Barmby, P Rigopoulou, D Egami, E McCracken, H Lilly, S Miyazaki, S Brodwin, M Blaylock, M Cadien, J Fazio, GG AF Ashby, M. L. N. Dye, S. Huang, J. -S. Eales, S. Willner, S. P. Webb, T. M. A. Barmby, P. Rigopoulou, D. Egami, E. McCracken, H. Lilly, S. Miyazaki, S. Brodwin, M. Blaylock, M. Cadien, J. Fazio, G. G. TI Mid-infrared identifications of scuba galaxies in the CUDSS 14 hour field with the Spitzer space telescope SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; galaxies : evolution; galaxies : formation; galaxies : high-redshift; infrared : galaxies; stars : formation ID DEEP SUBMILLIMETER SURVEY; STAR-FORMING GALAXIES; MULTIBAND IMAGING PHOTOMETER; ARRAY CAMERA IRAC; REDSHIFT SURVEY; INFRARED PROPERTIES; SOURCE EXTRACTION; 1ST-LOOK SURVEY; LOCKMAN HOLE; GROTH STRIP AB We identify 17 possible 8.0 mu m selected counterparts to the submillimeter galaxies in the CUDSS 14 hour field, derived from deep imaging carried out with the IRAC and MIPS instruments aboard the Spitzer Space Telescope. Ten of the 17 counterparts are not the same as those previously identified at shorter wavelengths. We argue that 8.0 mu m selection offers a better means for identifying counterparts to submillimeter galaxies than near-infrared or optical selection. Based on the panchromatic spectral energy distributions (SEDs), most counterparts appear to be powered by ongoing star formation. Power-law fits to the SEDs suggest that five objects in the 8.0 mu m selected counterpart sample harbor dominant active galactic nuclei (AGNs; a sixth object is identified as a possible AGN). The 3.6-8.0 mu m colors of the infrared-selected counterparts are significantly redder than the general IRAC galaxy population in the CUDSS 14 hour field. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Cardiff Univ, Sch Phys & Astron, Cardiff CF24 3YB, Wales. McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada. Univ Oxford, Dept Astrophys, DWB, Oxford OX1 3RH, England. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Inst Astrophys, F-75014 Paris, France. Swiss Fed Inst Technol, Dept Phys, Inst Astron, CH-8093 Zurich, Switzerland. Natl Astron Observ Japan, Subaru Telescope, Hilo, HI 96720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ashby, MLN (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM mashby@cfa.harvard.edu; jhuang@cfa.harvard.edu; swillner@cfa.harvard.edu; pbarmby@cfa.harvard.edu; gfazio@cfa.harvard.edu RI Barmby, Pauline/I-7194-2016; OI Barmby, Pauline/0000-0003-2767-0090; Dye, Simon/0000-0002-1318-8343 NR 42 TC 28 Z9 28 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 JUN 20 PY 2006 VL 644 IS 2 BP 778 EP 791 DI 10.1086/503861 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XS UT WOS:000238340100013 ER PT J AU Nuth, JA Wilkinson, GM Johnson, NM Dwyer, M AF Nuth, JA Wilkinson, GM Johnson, NM Dwyer, M TI A mechanism for the equilibrium growth of mineral crystals in AGB stars and red giants on 10(5) yr timescales SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; dust, extinction; stars : AGB and post-AGB ID ENVELOPES AB We show that for particle sizes ranging from a few hundred angstroms up to several tens of microns in diameter the force exerted by radiation pressure in some red giant and AGB stars exceeds the force of gravity and thus offers the potential for graphite, SiC, corundum, and spinel grains to grow to the size range observed in primitive meteorites ( e. g., up to similar to 25 mu m). In the highest mass AGB stars radiation pressure on growing grains greatly exceeds the force of gravity and thus ejects a grain from the star before it can grow larger than a few tens of nanometers. Only in very low mass AGB stars ( less than 3 M-circle dot) does the radiative force balance the gravitational force to such a fine degree that the net acceleration on individual particles ranging from a few nanometers up to about 25 mu m produces particle velocities that are comparable to atmospheric turbulence. Our analysis shows that the large graphite, SiC, corundum, and spinel crystals found in primitive meteorites can only have formed in the atmospheres of the lowest mass red giant and AGB stars, where particle growth is able to occur on timescales of a hundred thousand years under near-equilibrium conditions. We note that this suggestion is contrary to the standard assumption that grains can only form in stellar winds and implies that there may be a class of grains that can form in chemical equilibrium deep within the stellar atmosphere, just above the photosphere. C1 NASA, Goddard Space Flight Ctr, Astrochem Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. RP Nuth, JA (reprint author), NASA, Goddard Space Flight Ctr, Astrochem Lab, Code 691, Greenbelt, MD 20771 USA. RI Johnson, Natasha/E-3093-2012; Nuth, Joseph/E-7085-2012 NR 15 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 JUN 20 PY 2006 VL 644 IS 2 BP 1164 EP 1170 DI 10.1086/503700 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XS UT WOS:000238340100042 ER PT J AU Sarkar, G Sahai, R AF Sarkar, Geetanjali Sahai, Raghvendra TI The dust envelope of the preplanetary nebula IRAS 19475+3119 SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; dust, extinction; ISM : reflection nebulae; stars : AGB and post-AGB; stars : individual (IRAS 19475+3119); stars : mass loss ID CRYSTALLINE SILICATE DUST; PROTOPLANETARY NEBULAE; EVOLVED STARS; MASS-LOSS; PLANETARY-NEBULAE; WAVELENGTH SPECTROMETER; CIRCUMSTELLAR ENVELOPES; INTERSTELLAR EXTINCTION; OPTICAL-PROPERTIES; AGB STARS AB We present the spectral energy distribution ( SED) of the preplanetary nebula, IRAS 19475 + 3119 ( hereafter I 19475), from the optical to the far-infrared. We identify emission features due to crystalline silicates in the ISO SWS spectra of the star. We have fitted the SED of I 19475 using a one-dimensional radiative transfer code and find that a shell with inner and outer radii of 8: 8; 1016 and 4: 4; 1017 cm and dust temperatures ranging from about 94 to 46 K provides the best fit. The mass of this shell is greater than or similar to 1[ 34 cm(2) g(-1)/kappa( 100 mu m)] ( delta/200) M(circle dot), where kappa( 100 mu m) is the 100 mu m dust mass absorption coefficient ( per unit dust mass) and delta is the gas-to-dust ratio. In agreement with results from optical imaging and millimeter-wave observations of CO emission of I 19475, our model fits support an r(-3) density law for its dust shell, with important implications for the interaction process between the fast collimated post-AGB winds and the dense AGB envelopes that results in the observed shapes of PPNs and PNs. We find that the observed JCMT flux at submillimeter wavelengths ( 850 mu m) is a factor similar to 2 larger than our model flux, suggesting the presence of large dust grains in the dust shell of I 19475 that are not accounted for by our adopted standard MRN grain size distribution. C1 Indian Inst Technol, Dept Phys, Kanpur 208016, Uttar Pradesh, India. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sarkar, G (reprint author), Indian Inst Technol, Dept Phys, Kanpur 208016, Uttar Pradesh, India. NR 58 TC 15 Z9 15 U1 0 U2 5 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 JUN 20 PY 2006 VL 644 IS 2 BP 1171 EP 1182 DI 10.1086/503864 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XS UT WOS:000238340100043 ER PT J AU Willacy, K Langer, W Allen, M Bryden, G AF Willacy, K Langer, W Allen, M Bryden, G TI Turbulence-driven diffusion in protoplanetary disks: Chemical effects in the outer regions SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : abundances; ISM : molecules; planetary systems : protoplanetary disks; stars : formation ID T-TAURI STARS; MAIN-SEQUENCE STARS; GLOBAL BAROCLINIC INSTABILITY; YOUNG STELLAR OBJECTS; ACCRETION DISKS; SOLAR NEBULA; 2-DIMENSIONAL DISTRIBUTIONS; CIRCUMSTELLAR DISKS; INTERSTELLAR CLOUDS; GASEOUS MOLECULES AB The chemistry and dynamics of protoplanetary disks are likely to be intricately linked, with dynamical processes affecting the chemical composition and chemistry, in turn, controlling the ionization structure and hence the ability of a process such as the magnetorotational instability to drive turbulence. Here we present the results from chemical models of the outer disk, which include diffusive mixing driven by turbulence. We show that diffusion in the vertical direction can greatly affect the column densities of many molecules, increasing them by up to 2 orders of magnitude. Previous models have shown that disks consist of three chemically distinct layers, with the bulk of the observed molecular emission coming from a region between the cold midplane and the irradiated surface layers. Diffusion retains this structure, but increases the depth of the molecular layer, by bringing atoms and atomic ions formed by photodissociation in the layers into more shielded regions where the molecules can reform. The column densities of molecules whose abundances peak closer to the midplane, e. g., NH3 and N2H+, are not altered by diffusion. We find that diffusion does not affect the ionization fraction of the disk. We compare the calculated column densities to observations of DM Tau, LkCa 15, and TW Hya and find good agreement for many molecules for models with a diffusion coefficient of 10(18) cm(2) s(-1). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Div Geol Sci, Pasadena, CA 91125 USA. RP Willacy, K (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 81 TC 40 Z9 40 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 JUN 20 PY 2006 VL 644 IS 2 BP 1202 EP 1213 DI 10.1086/503702 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XS UT WOS:000238340100046 ER PT J AU Falconer, DA Moore, RL Gary, GA AF Falconer, D. A. Moore, R. L. Gary, G. A. TI Magnetic causes of solar coronal mass ejections: Dominance of the free magnetic energy over the magnetic twist alone SO ASTROPHYSICAL JOURNAL LA English DT Article DE sun : corona; sun : coronal mass ejections (CMEs); sun : flares; sun : magnetic fields; sun : X-rays, gamma rays ID ACTIVE REGIONS; VECTOR MAGNETOGRAMS; FIELD; FLARES; LINES; MSFC AB We examine the magnetic causes of coronal mass ejections (CMEs) by examining, along with the correlations of active-region magnetic measures with each other, the correlations of these measures with active-region CME productivity observed in time windows of a few days, either centered on or extending forward from the day of the magnetic measurement. The measures are from 36 vector magnetograms of bipolar active regions observed within similar to 30 degrees of disk center by the Marshal Space Flight Center (MSFC) vector magnetograph. From each magnetogram, we extract six whole-active-region measures twice, once from the original plane-of-the-sky magnetogram and again after deprojection of the magnetogram to disk center. Three of the measures are alternative measures of the total nonpotentiality of the active region, two are alternative measures of the overall twist in the active-region's magnetic field, and one is a measure of the magnetic size of the active region (the active region's magnetic flux content). From the deprojected magnetograms, we find evidence that (1) magnetic twist and magnetic size are separate but comparably strong causes of active-region CME productivity, and (2) the total free magnetic energy in an active region's magnetic field is a stronger determinant of the active region's CME productivity than is the field's overall twist (or helicity) alone. From comparison of results from the non-deprojected magnetograms with corresponding results from the deprojectedmagnetograms, we find evidence that (for prediction of active-region CME productivity and for further studies of active-region magnetic size as a cause of CMEs), for active regions within similar to 30 degrees of disk center, active-region total nonpotentiality and flux content can be adequately measured from line-of-sight magnetograms, such as from SOHO MDI. C1 George C Marshall Space Flight Ctr, SD50, Dept Space Sci, Huntsville, AL 35812 USA. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. RP Falconer, DA (reprint author), George C Marshall Space Flight Ctr, SD50, Dept Space Sci, Huntsville, AL 35812 USA. EM david.falconer@msfc.nasa.gov; ron.moore@nasa.gov; allen.gary@nasa.gov NR 33 TC 51 Z9 51 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 JUN 20 PY 2006 VL 644 IS 2 BP 1258 EP 1272 DI 10.1086/503699 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XS UT WOS:000238340100052 ER PT J AU Hammel, HB Lynch, DK Russell, RW Sitko, ML Bernstein, LS Hewagama, T AF Hammel, H. B. Lynch, D. K. Russell, R. W. Sitko, M. L. Bernstein, L. S. Hewagama, T. TI Mid-infrared ethane emission on neptune and uranus SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : solar system; planets and satellites : individual (Neptune, Uranus) ID MIXING RATIOS; MU-M; ATMOSPHERE; STRATOSPHERE; OCCULTATIONS; TEMPERATURE; SPECTRA; CONSTRAINTS; VARIABILITY; BRIGHTNESS AB We report 8 - 13 mu m spectral observations of Neptune and Uranus from the NASA Infrared Telescope Facility spanning more than a decade. The spectroscopic data indicate a steady increase in Neptune's mean atmospheric 12 mu m ethane emission from 1985 to 2003, followed by a slight decrease in 2004. The simplest explanation for the intensity variation is an increase in stratospheric effective temperature from 155 +/- 3 K in 1985 to 176 +/- 3 K in 2003 ( an average rate of 1.2 K yr(-1)) and a subsequent decrease to 165 +/- 3 K in 2004. We also detected variation of the overall spectral structure of the ethane band, specifically an apparent absorption structure in the central portion of the band; this structure arises from coarse spectral sampling coupled with a nonuniform response function within the detector elements. We also report a probable direct detection of ethane emission on Uranus. The deduced peak mole fraction is approximately 1 order of magnitude higher than previous upper limits for Uranus. The model fit suggests an effective temperature of 114 +/- 3 K for the globally averaged stratosphere of Uranus, which is consistent with recent measurements indicative of seasonal variation. C1 Space Sci Inst, Boulder, CO 80301 USA. Aerosp Corp, Los Angeles, CA 90009 USA. Spectral Sci Inc, Burlington, MA 01803 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hammel, HB (reprint author), Space Sci Inst, Boulder, CO 80301 USA. EM hbh@alum.mit.edu; David.K.Lynch@aero.org; Ray.W.Russell@aero.org; amazons@fuse.net; larry@spectral.com; tilak@cuzco.gsfc.nasa.gov RI Hewagama, T/C-8488-2012 NR 32 TC 18 Z9 18 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 JUN 20 PY 2006 VL 644 IS 2 BP 1326 EP 1333 DI 10.1086/503599 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XS UT WOS:000238340100058 ER PT J AU Johnson, BD Schiminovich, D Seibert, M Treyer, MA Charlot, S Heckman, TM Martin, DC Salim, S Kauffmann, G Bianchi, L Donas, J Friedman, PG Lee, YW Madore, BF Milliard, B Morrissey, P Neff, SG Rich, RM Szalay, AS Forster, K Barlow, TA Conrow, T Small, T Wyder, TK AF Johnson, BD Schiminovich, D Seibert, M Treyer, MA Charlot, S Heckman, TM Martin, DC Salim, S Kauffmann, G Bianchi, L Donas, J Friedman, PG Lee, YW Madore, BF Milliard, B Morrissey, P Neff, SG Rich, RM Szalay, AS Forster, K Barlow, TA Conrow, T Small, T Wyder, TK TI Dissecting galaxy colors with GALEX, SDSS, and SPITZER SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; galaxies : evolution; galaxies : ISM; infrared : galaxies; ultraviolet : galaxies ID STAR-FORMATION HISTORIES; DIGITAL SKY SURVEY; STARBURST GALAXIES; DUST ATTENUATION; FORMING GALAXIES; ULTRAVIOLET; UNIVERSE; LUMINOSITY; ABSORPTION AB We combine data from the Sloan Digital Sky Survey (SDSS), the Galaxy Evolution Explorer (GALEX), and the Spitzer Space Telescope to create a sample of galaxies observed homogeneously from the UV to the far-IR. This sample, consisting of similar to 460 galaxies observed spectroscopically by the SDSS, provides us with a multi-wavelength (0.15 - 24 mu m) view of obscured and unobscured star formation in nearby (z < 0.3) galaxies with star formation rates (SFRs) ranging from 0.01 to 100 M-. yr(-1). We calculate a robust dust measure from the infrared-to-UV ratio (or infrared excess [IRX]) and explore the influence of star formation history (SFH) on the dust-UV color relation (i.e., the IRX-beta relation). We find that the UV colors of galaxies are only weakly dependent on their SFH as measured by the 4000 break. However, we find that the contributions of dust and SFH are distinguishable when colors at widely separated wavelengths (e.g., 0.23 - 3.6 mu m) are introduced. We show this explicitly by recasting the IRX-beta relation as a more general IRX-SFH-color relation, which we examine in different projections. We also determine simple fits to this relation. C1 Columbia Univ, Dept Astron, New York, NY 10027 USA. CALTECH, Pasadena, CA 91125 USA. Lab Astrophys Marseille, F-13376 Marseille, France. Max Planck Inst Astrophys, D-85748 Garching, Germany. CNRS, Inst Astrophys Paris, F-75014 Paris, France. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA. Yonsei Univ, Ctr Space Astrophys, Seoul 120749, South Korea. Observ Carnegie Inst Washington, Pasadena, CA 91101 USA. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Johnson, BD (reprint author), Columbia Univ, Dept Astron, 550 W 120th St, New York, NY 10027 USA. EM bjohnson@astro.columbia.edu NR 22 TC 18 Z9 18 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 JUN 20 PY 2006 VL 644 IS 2 BP L109 EP L112 DI 10.1086/505741 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XY UT WOS:000238340700003 ER PT J AU Johnson, RE Smith, HT Tucker, OJ Liu, M Burger, MH Sittler, EC Tokar, RL AF Johnson, RE Smith, HT Tucker, OJ Liu, M Burger, MH Sittler, EC Tokar, RL TI The Enceladus and OH tori at Saturn SO ASTROPHYSICAL JOURNAL LA English DT Article DE planets and satellites : individual (Enceladus, Saturn) ID E-RING; NEUTRAL CLOUD; ATMOSPHERE; PLASMA; REDISTRIBUTION; PLUME; MODEL; ION AB The remarkable observation that Enceladus, a small icy satellite of Saturn, is actively venting has led to the suggestion that ejected water molecules are the source of the toroidal atmosphere observed at Saturn for over a decade using the Hubble Space Telescope (HST). Here we show that the venting leads directly to a new feature, a narrow Enceladus neutral torus. The larger torus, observed using HST, is populated by charge exchange, the process that limits the lifetime of the neutrals in the Enceladus torus. C1 Univ Virginia, Engn Phys & Astron Dept, Charlottesville, VA 22904 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Johnson, RE (reprint author), Univ Virginia, Engn Phys & Astron Dept, Charlottesville, VA 22904 USA. EM rej@virginia.edu RI Smith, Howard/H-4662-2016 OI Smith, Howard/0000-0003-3537-3360 NR 21 TC 88 Z9 88 U1 1 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 JUN 20 PY 2006 VL 644 IS 2 BP L137 EP L139 DI 10.1086/505750 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XY UT WOS:000238340700010 ER PT J AU Ofman, L Sui, L AF Ofman, L. Sui, L. TI Oscillations of hard X-ray flare emission observed by RHESSI: Effects of super-Alfvenic beams? SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; MHD; Sun : corona; Sun : flares; Sun : magnetic fields; Sun : X-rays, gamma rays; waves ID TEARING MODE-INSTABILITY; FULLY IONIZED GAS; MAGNETIC RECONNECTION; SOLAR-FLARES; CURRENT SHEETS; ION RUNAWAY; SHEAR-FLOW; EVOLUTION; ELECTRON; VISCOSITY AB Recent Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) observations of hard X-ray ( 125 keV) emission from several flares show damped oscillations with periods of 2 - 4 minutes and damping times of several tens of minutes. We analyze the observations of the 2005 January 19 flare that show the quasi-periodic, damped oscillations, and we propose a physical mechanism for this phenomenon. Namely, we suggest that super-Alfvenic beams in the vicinity of the reconnection region lead to the excitation of the oscillations. The oscillations damp as the flows and the reconnecting magnetic fields dissipate during the decay phase of the flare. We show the results of 2.5-dimensional viscoresistive MHD simulations of this mechanism, and we find qualitative agreement with the RHESSI observations. In addition, we find that the flows destabilize the current sheet, which leads to an increased reconnection rate compared to the case without the beams. C1 Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ofman, L (reprint author), Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. EM leon.ofman@gsfc.nasa.gov; linhui.sui@gsfc.nasa.gov NR 25 TC 40 Z9 40 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 JUN 20 PY 2006 VL 644 IS 2 BP L149 EP L152 DI 10.1086/505622 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XY UT WOS:000238340700013 ER PT J AU Lorenz, RD Witasse, O Lebreton, JP Blancquaert, T de Pater, I Mazoue, F Roe, H Lemmon, MT Burratti, BJ Holmes, S Noll, K AF Lorenz, RD Witasse, O Lebreton, JP Blancquaert, T de Pater, I Mazoue, F Roe, H Lemmon, MT Burratti, BJ Holmes, S Noll, K TI Huygens entry emission: Observation campaign, results, and lessons learned SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID EARTHS ATMOSPHERE; PROBE EXPERIMENT; PAET AB [ 1] An attempt was made to observe from Earth the emission from the shock layer and "meteor trail'' formed during the Huygens probe's hypersonic entry into Titan's atmosphere. Although many observations were wiped out by weather or in-orbit failure, two observations constrain the emission from the entry. Several important lessons for future observations of spacecraft and other entries can be drawn. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. ESA, ESTEC, Noordwijk, Netherlands. Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94730 USA. AOES, NL-2300 AH Leiden, Netherlands. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Lorenz, RD (reprint author), Univ Arizona, Lunar & Planetary Lab, 1629 E Univ Blvd, Tucson, AZ 85721 USA. EM rlorenz@lpi.arizona.edu RI Lemmon, Mark/E-9983-2010; Noll, Keith/C-8447-2012; Lorenz, Ralph/B-8759-2016 OI Lemmon, Mark/0000-0002-4504-5136; Lorenz, Ralph/0000-0001-8528-4644 NR 16 TC 2 Z9 2 U1 1 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 JUN 20 PY 2006 VL 111 IS E7 AR E07S11 DI 10.1029/2005JE002603 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 057MX UT WOS:000238601000001 ER PT J AU Canty, T Pickett, HM Salawitch, RJ Jucks, KW Traub, WA Waters, JW AF Canty, T Pickett, HM Salawitch, RJ Jucks, KW Traub, WA Waters, JW TI Stratospheric and mesospheric HOx: results from aura MLS and FIRS-2 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID VIBRATIONALLY EXCITED MOLECULES; O-3 DEFICIT PROBLEM; MIDDLE ATMOSPHERE; OZONE; OH; DILEMMA; RADICALS; CLUE; H2O AB Observations of OH and HO2 from Aura MLS for four seasons and diurnal profiles from the FIRS-2 balloon instrument for Fall 2004 are compared with photochemical model simulations testing three sets of kinetics parameters. MLS and FIRS-2 OH profiles, between 25 - 60 km, are lower than model results using standard kinetics. Use of a faster, previously published rate constant for O+OH leads to better agreement with MLS and FIRS-2 profiles of OH. A 20% increase in the rate of HO2+ OH and the faster rate for O+ OH results in improved overall agreement with observations of OH, HO2, HOx, and HO2/OH. Since the MLS and FIRS-2 observations of HOx are reasonably well described by these models, they are therefore not consistent with the previously reported HOx dilemma. However, all models considered here result in calculated odd oxygen loss exceeding production, consistent with the long standing ozone deficit problem. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Canty, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 183-601, Pasadena, CA 91109 USA. EM tcanty@jpl.nasa.gov RI Salawitch, Ross/B-4605-2009; Canty, Timothy/F-2631-2010 OI Salawitch, Ross/0000-0001-8597-5832; Canty, Timothy/0000-0003-0618-056X NR 14 TC 23 Z9 23 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 JUN 17 PY 2006 VL 33 IS 12 AR L12802 DI 10.1029/2006GL025964 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 057BO UT WOS:000238570100003 ER PT J AU Desai, SD Yuan, DN AF Desai, S. D. Yuan, D. -N. TI Application of the convolution formalism to the ocean tide potential: Results from the Gravity Recovery and Climate Experiment (GRACE) SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SATELLITE ALTIMETRY; MASS VARIABILITY; MODELS; PREDICTION; FIELDS AB [ 1] A computationally efficient approach to reducing omission errors in ocean tide potential models is derived and evaluated using data from the Gravity Recovery and Climate Experiment ( GRACE) mission. Ocean tide height models are usually explicitly available at a few frequencies, and a smooth unit response is assumed to infer the response across the tidal spectrum. The convolution formalism of Munk and Cartwright ( 1966) models this response function with a Fourier series. This allows the total ocean tide height, and therefore the total ocean tide potential, to be modeled as a weighted sum of past, present, and future values of the tide-generating potential. Previous applications of the convolution formalism have usually been limited to tide height models, but we extend it to ocean tide potential models. We use luni-solar ephemerides to derive the required tide-generating potential so that the complete spectrum of the ocean tide potential is efficiently represented. In contrast, the traditionally adopted harmonic model of the ocean tide potential requires the explicit sum of the contributions from individual tidal frequencies. It is therefore subject to omission errors from neglected frequencies and is computationally more intensive. Intersatellite range rate data from the GRACE mission are used to compare convolution and harmonic models of the ocean tide potential. The monthly range rate residual variance is smaller by 4 - 5%, and the daily residual variance is smaller by as much as 15% when using the convolution model than when using a harmonic model that is defined by twice the number of parameters. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Desai, SD (reprint author), CALTECH, Jet Prop Lab, M-S 238-600,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM shailen.desai@jpl.nasa.gov NR 32 TC 7 Z9 7 U1 0 U2 1 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 JUN 17 PY 2006 VL 111 IS C6 AR C06023 DI 10.1029/2005JC003361 PG 13 WC Oceanography SC Oceanography GA 057CE UT WOS:000238571900004 ER PT J AU Kahre, MA Murphy, JR Haberle, RM AF Kahre, MA Murphy, JR Haberle, RM TI Modeling the Martian dust cycle and surface dust reservoirs with the NASA Ames general circulation model SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID MARS ORBITER CAMERA; THERMAL EMISSION SPECTROMETER; PHYSICAL-PROPERTIES; MGS TES; ATMOSPHERIC CIRCULATION; INTERANNUAL VARIABILITY; MAPPER OBSERVATIONS; POLAR-REGIONS; SIMULATIONS; PATHFINDER AB [ 1] We employ the NASA Ames Mars general circulation model (GCM) to investigate the dust lifting mechanisms responsible for the observed Martian dust cycle and the net surface response to the combined influence of dust lifting and deposition. This GCM includes lifting, transport, and deposition of radiatively active dust. Two dust lifting mechanisms are accounted for: wind stress lifting and dust devil lifting. A "baseline'' simulation is presented and shown to compare well to available spatial and temporal observations of atmospheric opacity, wind stress dust lifting events, and atmospheric temperatures recorded during a nonglobal dust storm year. Multiple simulations were conducted to explore the model's sensitivity to a wide range of dust lifting parameters ( the functional dependence of surface dust flux on wind stress, the wind stress threshold for lifting, etc.) Model results robustly suggest that wind stress lifting produces the peak in atmospheric dust load during southern spring and summer and that dust devils maintain the background haze of atmospheric dust during northern spring and summer. These results are consistent with previously published conclusions. Dust devil and wind stress lifting contribute equally to the simulated total amount of dust lifted annually during nonglobal dust storm years. The simulated spatial pattern of annual net deflation/ deposition suggests that the low thermal inertia regions (Tharsis, Arabia, and Elysium) are not currently net dust accumulation regions. This net deflation is the result of dust devil dust lifting, suggesting that dust devils could play an important role in the present-day pattern of surface dust reservoirs. C1 New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Kahre, MA (reprint author), New Mexico State Univ, Dept Astron, MSC 4500 Box 30001, Las Cruces, NM 88003 USA. EM kahrema@nmsu.edu NR 50 TC 77 Z9 77 U1 1 U2 13 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 JUN 17 PY 2006 VL 111 IS E6 AR E06008 DI 10.1029/2005JE002588 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 057CH UT WOS:000238572200001 ER PT J AU Sittler, EC Blanc, MF Richardson, JD AF Sittler, EC Blanc, MF Richardson, JD TI Proposed model for Saturn's auroral response to the solar wind: Centrifugal instability model SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETIC-FIELD; PLASMA OBSERVATIONS; INTERCHANGE INSTABILITY; GEOMAGNETIC-ACTIVITY; QUANTITATIVE MODEL; SPACE-TELESCOPE; MAGNETOSPHERE; VOYAGER-1; CURRENTS; JUPITER AB [ 1] We present a model of Saturn's global auroral response to the solar wind as observed by simultaneous Hubble Space Telescope (HST) auroral images and Cassini upstream measurements of the solar wind taken during the month of January 2004. These observations show a direct correlation between solar wind dynamic pressure and ( 1) auroral brightening toward dawn local time, ( 2) an increase of rotational movement of auroral features to as much as 75% of the corotation speed, ( 3) the movement of the auroral oval to higher latitudes, and ( 4) an increase in the intensity of Saturn Kilometric Radiation (SKR). Our model, referred to as the centrifugal instability model, provides an alternative to the reconnection model of Cowley et al. ( 2004a, 2004b, 2005); we suggest the above observations result from Saturn's magnetosphere being a fast rotator. Since the torques on Saturn's outer magnetosphere are relatively low, its outer magnetosphere will tend to conserve angular momentum. When compressed on the dayside, the outer magnetosphere spins up to higher angular velocities, and when it expands, the outer magnetosphere spins down to lower angular velocities. This response occurs since Saturn's ionosphere is unable to enforce corotation. The outer boundary of the plasma sheet at L similar to 15 is identified as the primary source location for the auroral precipitating particles. Enhanced wave activity, which can precipitate the auroral producing particles, may be present at this boundary. If radial transport is dominated by centrifugally driven flux tube interchange motions, when the magnetosphere spins up, outward transport will increase, and the precipitating particles will move radially outward ( since the radial gradient in electron energy flux is negative). This mechanism will cause the auroral oval to move to higher latitudes as observed. The Kelvin-Helmholtz instability may contribute to the enhanced emission along the dawn meridian, as observed by HST, via enhanced wave activity and corresponding charged particle precipitation. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Ctr Etud Spatiale Rayonnements, F-31028 Toulouse 4, France. MIT, Space Res Ctr, Cambridge, MA 02139 USA. RP Sittler, EC (reprint author), NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd,Code 612-2, Greenbelt, MD 20771 USA. NR 60 TC 26 Z9 26 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 JUN 17 PY 2006 VL 111 IS A6 AR A06208 DI 10.1029/2005JA011191 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 057CR UT WOS:000238573400001 ER PT J AU Su, YJ Jones, ST Ergun, RE Bagenal, F Parker, SE Delamere, PA Lysak, RL AF Su, Yi-Jiun Jones, S. T. Ergun, R. E. Bagenal, F. Parker, S. E. Delamere, P. A. Lysak, R. L. TI Io-Jupiter interaction: Alfven wave propagation and ionospheric Alfven resonator SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PARALLEL ELECTRIC-FIELDS; JOVIAN S-BURSTS; PLASMA TORUS; AURORAL ARCS; MAGNETOSPHERE; MODEL; CONDUCTIVITY; TURBULENCE; EMISSION AB [ 1] A linear, one-dimensional gyrofluid code has been used to determine the characteristics of propagating Alfven waves and the ionospheric Alfven resonator on a Jupiter-Io flux tube. This model includes electron inertia, electron pressure gradient, and finite ion gyroradius effects, as well as the displacement current correction to prevent the Alfven velocity from exceeding the speed of light. A quasi-steady Vlasov code provides realistic density profiles along the flux tube as input parameters for the gyrofluid model. In this paper, we demonstrate that the majority of the wave energy from an initial pulse with a long wavelength ( similar to 0.1 R-J) is unable to reach Jupiter's ionosphere without wave breaking, phase mixing, and/or other nonlinear processes; however, a significant energy flux may be transferred via high-frequency, small-wavelength waves to the ionosphere. The waves that reach the ionosphere stimulate an ionospheric Alfven resonator which is generated between the ionospheric boundary and the first velocity peak of the Alfven phase speed. The ionospheric density and scale height play important roles to determine the resonant frequency. The eigenfrequency decreases with increasing scale height and with increasing ionospheric density. The fundamental frequency and higher harmonics of the Alfven resonator are comparable to the observed reoccurring frequency of S bursts between a few and hundreds of Hz. On the basis of this information, we suggest the Alfven resonator as the likely driver explaining multiple occurrences of S bursts. C1 Univ Texas, Dept Phys, Arlington, TX 76019 USA. NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80303 USA. Univ Colorado, Ctr Integrated Plasma Studies, Boulder, CO 80309 USA. Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. RP Su, YJ (reprint author), Univ Texas, Dept Phys, Box 19059, Arlington, TX 76019 USA. EM yijiun@uta.edu; samuel.t.jones.1@gsfc.nasa.gov; ree@fast.colorado.edu; fran.bagenal@lasp.colorado.edu; sparker@colorado.edu; peter.delamere@lasp.colorado.edu; bob@belka.space.umn.edu NR 47 TC 29 Z9 29 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 JUN 17 PY 2006 VL 111 IS A6 AR A06211 DI 10.1029/2005JA011252 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 057CR UT WOS:000238573400003 ER PT J AU Misawa, K Shih, CY Reese, Y Bogard, DD Nyquist, LE AF Misawa, K. Shih, C. -Y. Reese, Y. Bogard, D. D. Nyquist, L. E. TI Rb-Sr, Sm-Nd and Ar-Ar isotopic systematics of Martian dunite Chassigny SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE Martian meteorites; Rb-Sr; Sm-Nd; Ar-Ar; crystallization age; mantle source ID ANGRA-DOS-REIS; SNC METEORITES; EARLY DIFFERENTIATION; PARENT BODY; MARS; NAKHLITES; ABUNDANCES; COMPONENTS; CHRONOLOGY; EVOLUTION AB Isotopic analysis of the Martian meteorite Chassigny yields a Rb-Sr age of 1406 +/- 14 Ma with an initial Sr-87/Sr-86 ratio of 0.702251 +/- 0.000034, a Sm-Nd age of 1386 +/- 28 Ma with an initial epsilon(143Nd)-value of +16.9 +/- 0.3 and an Ar-39-Ar-40 age of 1360(+40)(-20) Ma. The concordance of these ages and the Rb-Sr and Sm-Nd initial isotopic signatures suggest that Chassigny crystallized from low Rb/Sr, light rare earth element depleted source materials similar to 1390 Ma ago. The ages and epsilon(143Nd)-values of Chassigny and the nakhlites Govenador Valadares and Lafayette overlap, suggesting that they could have come from very similar mantle sources. Nakhla, Northwest Africa 998 and Yamato 000593 appear to be from similar but distinct sources. Chassigny and all nakhlites so far studied have undergone similar evolution histories. That is, chassignites/nakhlites were derived from a region where volcanism lasted at least 50 Ma and crystallized from different lava flows or subsurface sills. They probably were launched from Mars by a single impact event. The trapped Martian atmospheric Ar-40/Ar-36 ratios in Chassigny, nakhlites and shergottite impact glass are similar and possibly indicate minimal change in this ratio over the past >= 600 Ma. (c) 2006 Elsevier B.V. All rights reserved. C1 Natl Inst Polar Res, Antarctic Meteorite Res Ctr, Tokyo 1738515, Japan. Grad Univ Adv Studies, Sch Multidisciplinary Sci, Tokyo 1738515, Japan. ESCG Jacobs Sverdrup, Houston, TX 77058 USA. ESCG Muniz Engn, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, ARES, Houston, TX 77058 USA. RP Misawa, K (reprint author), Natl Inst Polar Res, Antarctic Meteorite Res Ctr, 1-9-10 Kaga, Tokyo 1738515, Japan. EM misawa@nipr.ac.jp NR 49 TC 15 Z9 15 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X EI 1385-013X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD JUN 15 PY 2006 VL 246 IS 1-2 BP 90 EP 101 DI 10.1016/j.epsl.2006.03.044 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 066AE UT WOS:000239200800007 ER PT J AU Short, JW Maselko, JM Lindeberg, MR Harris, PM Rice, SD AF Short, JW Maselko, JM Lindeberg, MR Harris, PM Rice, SD TI Vertical distribution and probability of encountering intertidal Exxon Valdez oil on shorelines of three embayments within Prince William Sound, Alaska SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID CRUDE-OIL; SPILL; PERSISTENCE; BEACHES; RECOVERY; EXPOSURE; EMBRYOS AB We examined 32 shorelines selected at random in 2003 from shorelines in Herring Bay, Lower Pass, and Bay of Isles in Prince William Sound, Alaska, to examine the vertical distribution of oil remaining from the 1989 Exxon Valdez oil spill and to estimate the probability that sea otters and ducks would encounter oil while foraging there. On each shoreline, sampling was stratified by 1-m tide height intervals and randomly located 0.25 m(2) sampling quadrats were examined for evidence of surface and subsurface oil. Oil from the T/V Exxon Valdez was found on 14 shorelines, mainly in Herring Bay and Lower Pass, with an estimated 0.43 ha covered by surface oil and 1.52 ha containing subsurface oil. Surface and subsurface oil were most prevalent near the middle of the intertidal and had nearly symmetrical distributions with respect to tide height. Hence, about half the oil is in the biologically rich lower intertidal, where predators may encounter it while disturbing sediments in search of prey. The overall probability of encountering surface or subsurface oil is estimated as 0.0048, which is only slightly greater than our estimated probability of encountering subsurface oil in the lower intertidal of Herring Bay or Lower Pass. These encounter probabilities are sufficient to ensure that sea otters and ducks that routinely excavate sediments while foraging within the intertidal would likely encounter subsurface oil repeatedly during the course of a year. C1 NOAA, Auke Bay Lab, Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, Juneau, AK 99801 USA. RP Short, JW (reprint author), NOAA, Auke Bay Lab, Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, 11305 Glacier Highway, Juneau, AK 99801 USA. EM Jeff.Short@noaa.gov NR 23 TC 64 Z9 65 U1 1 U2 14 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD JUN 15 PY 2006 VL 40 IS 12 BP 3723 EP 3729 DI 10.1021/es0601134 PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 052FJ UT WOS:000238217200013 PM 16830533 ER PT J AU Davila, AF Rey, D Mohamed, K Rubio, B Guerra, AP AF Davila, AF Rey, D Mohamed, K Rubio, B Guerra, AP TI Mapping the sources of urban dust in a coastal environment by measuring magnetic parameters of Platanus hispanica leaves SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID TREE LEAVES; TRACE-ELEMENTS; AIR-POLLUTION; NW SPAIN; SEDIMENTS; IRON; PARTICULATE; MINERALS; METAL; RIA AB Tree leaves accumulate atmospheric particles on their surface, and a fraction of these particles exhibits magnetic properties that can be used to determine the spatial distribution of atmospheric dust in an urban area. This observation is exploited here to map sources of atmospheric pollutants in the coastal city of Vigo. The magnetic carriers on the leaves were iron oxide spherules ( 5-10 Am) and larger iron-bearing particles ( typically 10- 50 Am). The maximum values of magnetic remanence were very restricted in space and could be directly related to nearby polluting activities, such as road and railway traffic and shipyard and harbor activities; hence, our data represent main sources of urban dust in the city and not sinks. The concentrations of Fe, Zn, Ni, Pb, and Cu on the leaves showed a strong positive inter-correlation and also with the magnetic remanence of the leaves, suggesting common sources for these heavy metals and for the magnetic carriers. Mn and Cr did not show any significant correlation and their presence was linked to natural accumulations as micronutrients by the trees. The iron spherules and the heavy metal species identified here coincide with materials commonly found in sediments of the adjacent Ria de Vigo. The identification of the main sources of urban dust and heavy metals in the industrial and urban areas can, therefore, help in controlling these emissions to the Ria de Vigo. C1 Univ Vigo, Fac Ciencias, Dept Geociencias Marinas, Vigo 36310, Spain. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Davila, AF (reprint author), Univ Vigo, Fac Ciencias, Dept Geociencias Marinas, Campus Lagoas Marcosende S-N, Vigo 36310, Spain. RI Belen, Rubio/A-6326-2008; Davila, Alfonso/A-2198-2013; OI Davila, Alfonso/0000-0002-0977-9909; Rey, Daniel/0000-0001-9309-2562 NR 22 TC 28 Z9 32 U1 2 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD JUN 15 PY 2006 VL 40 IS 12 BP 3922 EP 3928 DI 10.1021/es0525049 PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 052FJ UT WOS:000238217200042 PM 16830562 ER PT J AU Gopalswamy, N Akiyama, S Yashiro, S Kasper, J AF Gopalswamy, N Akiyama, S Yashiro, S Kasper, J TI Comment on "Interplanetary shocks unconnected with earthbound coronal mass ejections'' by T.A. Howard and S.J. Tappin SO GEOPHYSICAL RESEARCH LETTERS LA English DT Editorial Material C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Catholic Univ Amer, Washington, DC 20064 USA. MIT, Boston, MA USA. RP Gopalswamy, N (reprint author), NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA. EM gopals@ssedmail.gsfc.nasa.gov RI Gopalswamy, Nat/D-3659-2012; Kasper, Justin/D-1152-2010; OI Kasper, Justin/0000-0002-7077-930X; Gopalswamy, Nat/0000-0001-5894-9954 NR 8 TC 2 Z9 2 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 JUN 15 PY 2006 VL 33 IS 11 AR L11108 DI 10.1029/2005GL024983 PG 3 WC Geosciences, Multidisciplinary SC Geology GA 057BM UT WOS:000238569900001 ER PT J AU Lin, JL Kiladis, GN Mapes, BE Weickmann, KM Sperber, KR Lin, W Wheeler, MC Schubert, SD Del Genio, A Donner, LJ Emori, S Gueremy, JF Hourdin, F Rasch, PJ Roeckner, E Scinocca, JF AF Lin, Jia-Lin Kiladis, George N. Mapes, Brian E. Weickmann, Klaus M. Sperber, Kenneth R. Lin, Wuyin Wheeler, Matthew C. Schubert, Siegfried D. Del Genio, Anthony Donner, Leo J. Emori, Seita Gueremy, Jean-Francois Hourdin, Frederic Rasch, Philip J. Roeckner, Erich Scinocca, John F. TI Tropical intraseasonal variability in 14 IPCC AR4 climate models. Part I: Convective signals SO JOURNAL OF CLIMATE LA English DT Review ID MADDEN-JULIAN OSCILLATION; GENERAL-CIRCULATION MODEL; OUTGOING LONGWAVE RADIATION; COUPLED EQUATORIAL WAVES; ASIAN SUMMER MONSOON; WESTERLY WIND BURSTS; AIR-SEA INTERACTION; LARGE-SCALE MODELS; CUMULUS PARAMETERIZATION; MULTISCALE MODEL AB This study evaluates the tropical intraseasonal variability, especially the fidelity of Madden-Julian oscillation (MJO) simulations, in 14 coupled general circulation models (GCMs) participating in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). Eight years of daily precipitation from each model's twentieth-century climate simulation are analyzed and compared with daily satellite-retrieved precipitation. Space-time spectral analysis is used to obtain the variance and phase speed of dominant convectively coupled equatorial waves, including the MJO, Kelvin, equatorial Rossby (ER), mixed Rossby-gravity (MRG), and eastward inertio-gravity (EIG) and westward inertio-gravity (WIG) waves. The variance and propagation of the MJO, defined as the eastward wavenumbers 1-6, 30-70-day mode, are examined in detail. The results show that current state-of-the-art GCMs still have significant problems and display a wide range of skill in simulating the tropical intraseasonal variability. The total intraseasonal (2-128 day) variance of precipitation is too weak in most of the models. About half of the models have signals of convectively coupled equatorial waves, with Kelvin and MRG-EIG waves especially prominent. However, the variances are generally too weak for all wave modes except the EIG wave, and the phase speeds are generally too fast, being scaled to excessively deep equivalent depths. An interesting result is that this scaling is consistent within a given model across modes, in that both the symmetric and antisymmetric modes scale similarly to a certain equivalent depth. Excessively deep equivalent depths suggest that these models may not have a large enough reduction in their "effective static stability" by diabatic heating. The MJO variance approaches the observed value in only 2 of the 14 models, but is less than half of the observed value in the other 12 models. The ratio between the eastward MJO variance and the variance of its westward counterpart is too small in most of the models, which is consistent with the lack of highly coherent eastward propagation of the MJO in many models. Moreover, the MJO variance in 13 of the 14 models does not come from a pronounced spectral peak, but usually comes from part of an over-reddened spectrum, which in turn is associated with too strong persistence of equatorial precipitation. The two models that arguably do best at simulating the MJO are the only ones having convective closures/triggers linked in some way to moisture convergence. C1 NOAA, CIRES Climate Diagnost Ctr, Boulder, CO 80305 USA. NOAA, Aeron Lab, Boulder, CO 80305 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. Lawrence Livermore Natl Lab, PCMDI, Livermore, CA USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Bur Meteorol Res Ctr, Melbourne, Vic, Australia. NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Of, Greenbelt, MD 20771 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ USA. Natl Inst Environm Studies, Ibaraki, Japan. CNRM, Meteo France, Toulouse, France. Univ Paris, Lab Meteorol Dynam, F-75252 Paris, France. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Max Planck Inst Meteorol, Hamburg, Germany. Canadian Ctr Climate Modelling & Anal, Victoria, BC, Canada. RP Lin, JL (reprint author), NOAA, CIRES Climate Diagnost Ctr, 325 Broadway,R-CDC1, Boulder, CO 80305 USA. EM jialin.lin@noaa.gov RI Mapes, Brian/A-5647-2010; Emori, Seita/D-1950-2012; Del Genio, Anthony/D-4663-2012; Wheeler, Matthew/C-9038-2011; Sperber, Kenneth/H-2333-2012 OI Del Genio, Anthony/0000-0001-7450-1359; Wheeler, Matthew/0000-0002-9769-1973; NR 107 TC 451 Z9 460 U1 3 U2 41 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 JUN 15 PY 2006 VL 19 IS 12 BP 2665 EP 2690 DI 10.1175/JCLI3735.1 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 057ZT UT WOS:000238634500003 ER PT J AU Shin, SI Sardeshmukh, PD Webb, RS Oglesby, RJ Barsugli, JJ AF Shin, Sang-Ik Sardeshmukh, Prashant D. Webb, Robert S. Oglesby, Robert J. Barsugli, Joseph J. TI Understanding the mid-Holocene climate SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; AUSTRALIAN SUMMER MONSOON; EL-NINO; INTERCOMPARISON PROJECT; SOUTHERN-OSCILLATION; AFRICAN MONSOON; MIDDLE HOLOCENE; GLOBAL CLIMATE; UNITED-STATES; LAKE-STATUS AB Paleoclimatic evidence suggests that during the mid-Holocene epoch (about 6000 yr ago) North America and North Africa were significantly drier and wetter, respectively, than at present. Modeling efforts to attribute these differences to changes in orbital parameters and greenhouse gas (GHG) levels have had limited success, especially over North America. In this study, the importance of a possibly cooler tropical Pacific Ocean during the epoch (akin to a permanent La Nina-like perturbation to the present climate) incausing these differences is emphasized. Systematic sets of atmospheric general circulation model experiments, with prescribed sea surface temperatures (SSTs) in the tropical Pacific basin and an interactive mixed layer ocean elsewhere, are performed. Given the inadequacies of current fully coupled climate models in simulating the tropical Pacific climate, this intermediate coupling model configuration is argued to be more suitable for quantifying the contributions of the altered orbital forcing, GHG levels, and tropical Pacific SST conditions to the different mid-Holocene climates. The simulated responses in this configuration are in fact generally more consistent with the available evidence from paleovegetation and sedimentary records. Coupling to the mixed layer ocean enhances the wind-evaporation-SST feedback over the tropical Atlantic Ocean. The net response to the orbital changes is to shift the North Atlantic intertropical convergence zone (ITCZ) northward, and make North Africa wetter. The response to the reduced GHG levels opposes, but does not eliminate, these changes. The northward-shifted ITCZ also blocks the moisture supply from the Gulf of Mexico into North America. This drying tendency is greatly amplified by the local response to La Nina-like conditions in the tropical Pacific. Consistent with the paleoclimatic evidence, the simulated North American drying is also most pronounced in the growing (spring) season. C1 NOAA, Earth Syst Res Lab, Boulder, CO 80305 USA. CIRES Climate Diagnost Ctr, Boulder, CO 80305 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Shin, SI (reprint author), NOAA, Earth Syst Res Lab, 325 Broadway,R-PSD1, Boulder, CO 80305 USA. EM sangik.shin@noaa.gov RI Barsugli, Joseph/K-3541-2015 OI Barsugli, Joseph/0000-0002-3078-6396 NR 40 TC 27 Z9 27 U1 3 U2 8 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 JUN 15 PY 2006 VL 19 IS 12 BP 2801 EP 2817 DI 10.1175/JCLI3733.1 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 057ZT UT WOS:000238634500009 ER PT J AU Dubovik, O Sinyuk, A Lapyonok, T Holben, BN Mishchenko, M Yang, P Eck, TF Volten, H Munoz, O Veihelmann, B van der Zande, WJ Leon, JF Sorokin, M Slutsker, I AF Dubovik, Oleg Sinyuk, Alexander Lapyonok, Tatyana Holben, Brent N. Mishchenko, Michael Yang, Ping Eck, Tom F. Volten, Hester Munoz, Olga Veihelmann, Ben van der Zande, Wim J. Leon, Jean-Francois Sorokin, Michael Slutsker, Ilya TI Application of spheroid models to account for aerosol particle nonsphericity in remote sensing of desert dust SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review ID RESEARCH SCANNING POLARIMETER; SKY RADIANCE MEASUREMENTS; GROUND-BASED MEASUREMENTS; LIGHT-SCATTERING; OPTICAL-PROPERTIES; SAHARAN DUST; SIZE DISTRIBUTION; TROPOSPHERIC AEROSOLS; SURFACE-ROUGHNESS; ICE CRYSTALS AB [ 1] The possibility of using shape mixtures of randomly oriented spheroids for modeling desert dust aerosol light scattering is discussed. For reducing calculation time, look-up tables were simulated for quadrature coefficients employed in the numerical integration of spheroid optical properties over size and shape. The calculations were done for 25 bins of the spheroid axis ratio ranging from similar to 0.3 ( flattened spheroids) to similar to 3.0 ( elongated spheroids) and for 41 narrow size bins covering the size parameter range from similar to 0.012 to similar to 625. The look-up tables were arranged into a software package, which allows fast, accurate, and flexible modeling of scattering by randomly oriented spheroids with different size and shape distributions. In order to evaluate spheroid model and explore the possibility of aerosol shape identification, the software tool has been integrated into inversion algorithms for retrieving detailed aerosol properties from laboratory or remote sensing polarimetric measurements of light scattering. The application of this retrieval technique to laboratory measurements by Volten et al. ( 2001) has shown that spheroids can closely reproduce mineral dust light scattering matrices. The spheroid model was utilized for retrievals of aerosol properties from atmospheric radiation measured by AERONET ground-based Sun/sky-radiometers. It is shown that mixtures of spheroids allow rather accurate fitting of measured spectral and angular dependencies of observed intensity and polarization. Moreover, it is shown that for aerosol mixtures with a significant fraction of coarse-mode particles ( radii >= similar to 1 mu m), the nonsphericity of aerosol particles can be detected as part of AERONET retrievals. The retrieval results indicate that nonspherical particles with aspect ratios similar to 1.5 and higher dominate in desert dust plumes, while in the case of background maritime aerosol spherical particles are dominant. Finally, the potential of using AERONET derived spheroid mixtures for modeling the effects of aerosol particle nonsphericity in other remote sensing techniques is discussed. For example, the variability of lidar measurements ( extinction to backscattering ratio and signal depolarization ratio) is illustrated and analyzed. Also, some potentially important differences in the sensitivity of angular light scattering to parameters of nonspherical versus spherical aerosols are revealed and discussed. C1 NASA, Terr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Inst Astrofis Andalucia, E-18080 Granada, Spain. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Radboud Univ Nijmegen, Inst Mol & Mat, NL-6500 GL Nijmegen, Netherlands. Univ Lille 1, CNRS, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. RP Dubovik, O (reprint author), Univ Lille 1, CNRS, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. EM dubovik@loa.univ-lille1.fr RI Dubovik, Oleg/A-8235-2009; ECK, THOMAS/D-7407-2012; Yang, Ping/B-4590-2011; Mishchenko, Michael/D-4426-2012; OI Dubovik, Oleg/0000-0003-3482-6460; Munoz, Olga/0000-0002-5138-3932 NR 106 TC 525 Z9 534 U1 9 U2 88 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 JUN 15 PY 2006 VL 111 IS D11 AR D11208 DI 10.1029/2005JD006619 PG 34 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 057BR UT WOS:000238570500003 ER PT J AU Stajner, I Wargan, K Chang, LP Hayashi, H Pawson, S Nakajima, H AF Stajner, Ivanka Wargan, Krzysztof Chang, Lang-Ping Hayashi, Hiroo Pawson, Steven Nakajima, Hideaki TI Assimilation of ozone profiles from the Improved Limb Atmospheric Spectrometer-II: Study of Antarctic ozone SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TRANSPORT; SYSTEM; STRATOSPHERE; VALIDATION; ALGORITHM; VORTEX AB [ 1] Ozone data from the Improved Limb Atmospheric Spectrometer- II (ILAS-II) were included in addition to other satellite observations in the ozone assimilation system at the Global Modeling and Assimilation Office (GMAO) of NASA/Goddard. The control run assimilated data from NOAA 16 Solar Backscatter Ultraviolet/2 (SBUV/2) and Polar Ozone and Aerosol Measurement III (POAM III) instruments. Persistent impacts over Antarctica and transient impacts over northern middle and high latitudes are seen from April to October 2003, when ILAS-II provided good coverage. The largest improvements with respect to independent ozone sonde data are seen over the South Pole station. Ozone analyses and forecasts from the assimilation of SBUV/2, POAM III and ILAS- II data are used to investigate the transport of ozone to southern middle latitudes following the breakup of the Antarctic vortex. The quality of analyses and forecasts is evaluated by comparison with independent Stratospheric Aerosol and Gas Experiment III ( SAGE III) ozone data near 46 degrees S. Anomaly correlations between SAGE III data and forecasts are improved at 70 hPa when occultation data are included. C1 NASA, Global Modeling & Assimilat Off, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Applicat Int Corp, Beltsville, MD USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Natl Inst Environm Studies, Tsukuba, Ibaraki 3058506, Japan. RP Stajner, I (reprint author), NASA, Global Modeling & Assimilat Off, Goddard Space Flight Ctr, Code 610-1, Greenbelt, MD 20771 USA. EM istajner@gmao.gsfc.nasa.gov; kwargan@gmao.gsfc.nasa.gov; lpchang@gmao.gsfc.nasa.gov; hhayashi@gmao.gsfc.nasa.gov; spawson@gmao.gsfc.nasa.gov RI Stajner, Ivanka/B-5228-2009; Pawson, Steven/I-1865-2014; OI Stajner, Ivanka/0000-0001-6103-3939; Pawson, Steven/0000-0003-0200-717X; Wargan, Krzysztof/0000-0002-3795-2983 NR 30 TC 9 Z9 9 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 JUN 15 PY 2006 VL 111 IS D11 AR D11S14 DI 10.1029/2005JD006448 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 057BR UT WOS:000238570500002 ER PT J AU Park, C Wilkinson, J Banda, S Ounaies, Z Wise, KE Sauti, G Lillehei, PT Harrison, JS AF Park, C Wilkinson, J Banda, S Ounaies, Z Wise, KE Sauti, G Lillehei, PT Harrison, JS TI Aligned single-wall carbon nanotube polymer composites using an electric field SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE alignment; electric field; nanocomposite; photopolymerization; single-wall carbon nanotube ID POLYIMIDE; PERCOLATION; SENSORS; FLUIDS; AC AB While high shear alignment has been shown to improve the mechanical properties of single-wall carbon nanotube (SWNT)-polymer composites, this method does not allow for control over the electrical and dielectric properties of the composite and often results in degradation of these properties. Here, we report a novel method to actively align SWNTs in a polymer matrix, which permits control over the degree of alignment of the SWNTs without the side effects of shear alignment. In this process, SWNTs were aligned via AC field-induced dipolar interactions among the nanotubes in a liquid matrix followed by immobilization by photopolymerization under continued application of the electric field. Alignment of SWNTs was controlled as a function of magnitude, frequency, and application time of the applied electric field. The degree of SWNT alignment was assessed using optical microscopy and polarized Raman spectroscopy, and the morphology of the aligned nanocomposites was investigated by high-resolution scanning electron microscopy. The structure of the field induced aligned SWNTs was intrinsically different from that of shear aligned SWNTs. In the present work, SWNTs are not only aligned along the field, but also migrate laterally to form thick, aligned SWNT percolative columns between the electrodes. The actively aligned SWNTs amplify the electrical and dielectric properties of the composite. All of these properties of the aligned nanocomposites exhibited anisotropic characteristics, which were controllable by tuning the applied field parameters. (c) 2006 Wiley Periodicals, Inc. C1 NASA, Langley Res Ctr, Natl Inst Aerosp, Hampton, VA 23681 USA. Virginia Tech, Dept Elect Engn, Blacksburg, VA USA. Virginia Commonwealth Univ, Dept Mech Engn, Richmond, VA USA. Univ Witwatersrand, Sch Phys, Johannesburg, South Africa. NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. RP Park, C (reprint author), NASA, Langley Res Ctr, Natl Inst Aerosp, Hampton, VA 23681 USA. EM c.park@larc.nasa.gov RI Lillehei, Peter/C-9196-2009 OI Lillehei, Peter/0000-0001-8183-9980 NR 32 TC 132 Z9 133 U1 9 U2 54 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD JUN 15 PY 2006 VL 44 IS 12 BP 1751 EP 1762 DI 10.1002/polb.20823 PG 12 WC Polymer Science SC Polymer Science GA 048YQ UT WOS:000237982900011 ER PT J AU Hu, YX Liu, ZY Winker, D Vaughan, M Noel, V Bissonnette, L Roy, G McGill, M AF Hu, YX Liu, ZY Winker, D Vaughan, M Noel, V Bissonnette, L Roy, G McGill, M TI Simple relation between lidar multiple scattering and depolarization for water clouds SO OPTICS LETTERS LA English DT Article ID BACKSCATTER; EXTINCTION; PHASE AB An empirical relationship is derived between the multiple-scattering fraction and the linear depolarization ratio by using Monte Carlo simulations of water clouds measured by backscatter lidar. This relationship is shown to hold for clouds having a wide range of extinction coefficients, mean droplet sizes, and droplet size distribution widths. The relationship is also shown to persist for various instrument fields of view and for measurements made within broken cloud fields. The results obtained from the Monte Carlo simulations are verified by using multiple-field-of-view lidar measurements. For space-based lidars equipped to measure linear depolarization ratios, this new relationship can be used to accurately assess signal perturbations due to multiple scattering within nonprecipitating water clouds. (c) 2006 Optical Society of America. C1 NASA, Langley Res Ctr, Climate Sci Branch, Hampton, VA 23681 USA. DRDC Valcartier, Val Belair, PQ G3J 1X5, Canada. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hu, YX (reprint author), NASA, Langley Res Ctr, Climate Sci Branch, Hampton, VA 23681 USA. RI Liu, Zhaoyan/A-9604-2009; Liu, Zhaoyan/B-1783-2010; McGill, Matthew/D-8176-2012; Hu, Yongxiang/K-4426-2012; OI Liu, Zhaoyan/0000-0003-4996-5738; Noel, Vincent/0000-0001-9494-0340 NR 8 TC 45 Z9 46 U1 1 U2 10 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUN 15 PY 2006 VL 31 IS 12 BP 1809 EP 1811 DI 10.1364/OL.31.001809 PG 3 WC Optics SC Optics GA 051JG UT WOS:000238156800011 PM 16729078 ER PT J AU Teillet, PM Markham, BL Irish, RR AF Teillet, PM Markham, BL Irish, RR TI Landsat cross-calibration based on near simultaneous imaging of common ground targets SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE landsat; radiometric calibration; vicarious calibration ID SENSORS; ETM+ AB The paper presents the results of an extended analysis of image data sets acquired during the tandem-orbit configuration in 1999 for the purposes of radiometric cross-calibration of the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) and Landsat-5 Thematic Mapper (TM) sensors. Earlier work focused on the tandem pair for the Railroad Valley Playa, Nevada (RVPN) site to tie down the Landsat-5 TM calibration based on the more accurate Landsat-7 ETM+ calibration. This paper describes new results based on as many as eight tandem image pairs. The additional tandem images are of primarily vegetated areas for which little or no ground reference data were available. Increasing the number of tandem pairs yielded results for the Landsat 5 TM gain coefficients within approximately +/- 1% of the RVPN-based results in spectral bands 1, 2, 3 and 7, and within -2% and -4% of the RVPN-based results for spectral bands 4 and 5, respectively. Crown Copyright (c) 2006 Published by Elsevier Inc. All rights reserved. C1 Canada Ctr Remote Sensing, Ottawa, ON K1A OY7, Canada. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP Teillet, PM (reprint author), Canada Ctr Remote Sensing, 588 Booth St, Ottawa, ON K1A OY7, Canada. EM phil.teillet@nrean.gc.ca RI Markham, Brian/M-4842-2013 OI Markham, Brian/0000-0002-9612-8169 NR 10 TC 35 Z9 39 U1 2 U2 8 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 JUN 15 PY 2006 VL 102 IS 3-4 BP 264 EP 270 DI 10.1016/j.rse.2006.02.005 PG 7 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 054VF UT WOS:000238406000006 ER PT J AU Henderson, MG Skoug, R Donovan, E Thomsen, MF Reeves, GD Denton, MH Singer, HJ McPherron, RL Mende, SB Immel, TJ Sigwarth, JB Frank, LA AF Henderson, M. G. Skoug, R. Donovan, E. Thomsen, M. F. Reeves, G. D. Denton, M. H. Singer, H. J. McPherron, R. L. Mende, S. B. Immel, T. J. Sigwarth, J. B. Frank, L. A. TI Substorms during the 10-11 August 2000 sawtooth event SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PERIODIC MAGNETOSPHERIC SUBSTORMS; INTERPLANETARY MAGNETIC-FIELD; SOLAR-WIND CHANGES; POLAR-CAP INDEX; DYNAMIC PRESSURE; ART.; TIME; INJECTIONS; BEHAVIOR; CDAW-9 AB [ 1] Sawtooth events have been identified at geosynchronous orbit as large-amplitude quasiperiodic ( 2 - 4 hour period) modulations of the energetic electron and ion fluxes. They are called sawtooth events because the shape of the flux versus time profiles are composed of rapid increases followed by gradual decreases that resemble the teeth on a saw blade. Although much of the phenomenology associated with sawtooth events is substorm-like, there is still debate as to whether the individual teeth are substorms or not. Here we examine each of the teeth associated with the 10 - 11 August 2000 sawtooth event in detail. We find that all but one of the teeth were associated with injections at geosynchronous orbit and that most of the teeth were consistent with the hypothesis that they are predominantly caused by unusually large and longitudinally extended substorms. A few were unclear or complex, and the final flux enhancement at 1845: 36 UT was not a substorm but a solar wind shock-associated disturbance. In addition, the presence of numerous dispersionless flux perturbations in the LANL SOPA data provides support for the hypothesis that solar wind pressure variations can modulate the flux profiles to some extent. For the substorm events we find that the geosynchronous particle injections were neither globally simultaneous nor globally dispersionless but were instead consistent with a nightside/duskside source in most cases. Similarly, we show that the field dipolarizations were also not global and simultaneous. Each of the substorms was also associated with high-latitude negative H bays, middle- and low-latitude positive H bays, a partial recovery in Sym-H, and the onset of Pi2 ULF pulsations. In addition, we show that the auroral distribution develops in a systematic way during each cycle of a sawtooth substorm event. Specifically, a localized auroral onset develops on the lower branch of a thinned double-oval distribution. The location of onset is typically premidnight and often occurs to the west of intense omega band forms. This is followed by westward, eastward, and poleward expansion and the copious production of auroral streamers which can develop in complex patterns including a "spoke-like'' morphology. The double-oval configuration thins again during the stretching phase until the next onset occurs and the cycle repeats. A schematic representation of the auroral dynamics associated with sawtooth substorms is also presented. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calgary, Dept Phys & Astron, Calgary, AB T2N 1N4, Canada. NOAA, Space Environm Ctr, Boulder, CO 80305 USA. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. RP Henderson, MG (reprint author), Los Alamos Natl Lab, MS D-466, Los Alamos, NM 87545 USA. EM mghenderson@lanl.gov RI Reeves, Geoffrey/E-8101-2011; Henderson, Michael/A-3948-2011; OI Reeves, Geoffrey/0000-0002-7985-8098; Henderson, Michael/0000-0003-4975-9029; Donovan, Eric/0000-0002-8557-4155; Denton, Michael/0000-0002-1748-3710 NR 43 TC 43 Z9 43 U1 0 U2 9 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 JUN 14 PY 2006 VL 111 IS A6 AR A06206 DI 10.1029/2005JA011366 PG 32 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 057CN UT WOS:000238572800002 ER PT J AU Neophytou, N Kienle, D Polizzi, E Anantram, MP AF Neophytou, N Kienle, D Polizzi, E Anantram, MP TI Influence of defects on nanotube transistor performance SO APPLIED PHYSICS LETTERS LA English DT Article ID FIELD-EFFECT TRANSISTORS; CARBON NANOTUBES; CONDUCTANCE AB We study the effect of vacancies and charged impurities on the performance of carbon nanotube transistors by self-consistently solving the three-dimensional Poisson and Schrodinger equations. We find that a single vacancy or charged impurity can decrease the drive current by more than 25% from the ballistic current. The threshold voltage shift in the case of charged impurities can be as large as 40 mV. (c) 2006 American Institute of Physics. C1 Purdue Univ, Sch Elect & Comp Engn, W Lafayette, IN 47907 USA. Univ Massachusetts, ECE Dept, Amherst, MA 01003 USA. NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Neophytou, N (reprint author), Purdue Univ, Sch Elect & Comp Engn, W Lafayette, IN 47907 USA. EM neophyto@purdue.edu RI Polizzi, Eric/J-8744-2013 NR 21 TC 24 Z9 24 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 12 PY 2006 VL 88 IS 24 AR 242106 DI 10.1063/1.2211932 PG 3 WC Physics, Applied SC Physics GA 053OP UT WOS:000238314800048 ER PT J AU Savchenkov, AA Matsko, AB Strekalov, D Ilchenko, VS Maleki, L AF Savchenkov, AA Matsko, AB Strekalov, D Ilchenko, VS Maleki, L TI Photorefractive effects in magnesium doped lithium niobate whispering gallery mode resonators SO APPLIED PHYSICS LETTERS LA English DT Article ID HIGH LIGHT INTENSITIES; LINBO3; DAMAGE; CRYSTALS AB We report on the study of near-infrared photorefractivity in highly Mg doped as-grown congruent LiNbO3 forming a whispering gallery mode resonator. The resonator is pumped with 780 nm light. We have observed a change of the ordinary index of refraction of the material exceeding 8x10(-5). We show that the basic features of the photorefraction in this type of crystal is different from the photorefraction in nominally pure as-grown congruent LiNbO3 and explain the origin of this difference. (c) 2006 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Savchenkov, AA (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 14 TC 10 Z9 10 U1 0 U2 6 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 JUN 12 PY 2006 VL 88 IS 24 AR 241909 DI 10.1063/1.2212055 PG 3 WC Physics, Applied SC Physics GA 053OP UT WOS:000238314800027 ER PT J AU Patorski, K Styk, A Bruno, L Szwaykowski, P AF Patorski, Krzysztof Styk, Adam Bruno, Luigi Szwaykowski, Piotr TI Tilt-shift error detection in phase-shifting interferometry SO OPTICS EXPRESS LA English DT Article ID ALGORITHM; CALIBRATION AB Temporal phase shifting in automatic interferogram analysis offers very high accuracy of phase retrieval providing that several experimental conditions are met. The paper is focused on the calibration error of unequal phase changes across the interferogram field, i.e., tilt-shift error. For its detection the lattice-site representation of phase shift angles is proposed. The error can be readily discerned using (N+1) algorithms with the last frame overlapping the first one. Four and five frame algorithms are considered. The influence of experimental parameters on the error detection sensitivity is discussed. Numerical studies are complemented by experimental results. (c) 2006 Optical Society of America. C1 Warsaw Univ Technol, Inst Micromech & Photon, PL-02525 Warsaw, Poland. Univ Calabria, Dept Mech Engn, I-87036 Arcavacata Di Rende, Italy. Engn Synthesis Design Inc, Tucson, AZ 85711 USA. Jet Propuls Lab, Pasadena, CA 91109 USA. RP Patorski, K (reprint author), Warsaw Univ Technol, Inst Micromech & Photon, 8 Sw A Boboli St, PL-02525 Warsaw, Poland. EM k.patorski@mchtr.pw.edu.pl; a.styk@mchtr.pw.edu.pl; bruno@unical.it; piotr@ispwest.com RI Bruno, Luigi/Q-7702-2016; OI Bruno, Luigi/0000-0002-6745-0466 NR 22 TC 14 Z9 15 U1 0 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 JUN 12 PY 2006 VL 14 IS 12 BP 5232 EP 5249 DI 10.1364/OE.14.005232 PG 18 WC Optics SC Optics GA 055GI UT WOS:000238437800036 PM 19516689 ER PT J AU Kletetschka, G AF Kletetschka, G TI Comment on a paper "The origin of high magnetic remanence in fault pseudotachylites: Theoretical considerations and implication for coseismic electrical currents" by E.C. Ferre, M.S. Zechmeister, J.W. Geissman, N.Mathana Sekaran, and K. Kocak SO TECTONOPHYSICS LA English DT Editorial Material C1 Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. Acad Sci Czech Republ, Inst Geol, Prague, Czech Republic. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kletetschka, G (reprint author), Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. EM gunther.kletetschka@gsfc.nasa.gov RI Kletetschka, Gunther/C-9996-2011 OI Kletetschka, Gunther/0000-0002-0645-9037 NR 3 TC 1 Z9 1 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-1951 J9 TECTONOPHYSICS JI Tectonophysics PD JUN 12 PY 2006 VL 419 IS 1-4 BP 99 EP 99 DI 10.1016/j.tecto.2006.03.011 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 056LV UT WOS:000238525300007 ER PT J AU Donzelli, S Maino, D Bersanelli, M Childers, J Figueiredo, N Lubin, PM Meinhold, PR O'Dwyer, IJ Seiffert, MD Villela, T Wandelt, BD Wuensche, CA AF Donzelli, S Maino, D Bersanelli, M Childers, J Figueiredo, N Lubin, PM Meinhold, PR O'Dwyer, IJ Seiffert, MD Villela, T Wandelt, BD Wuensche, CA TI Angular power spectrum of the FASTICA cosmic microwave background component from Background Emission Anisotropy Scanning Telescope data SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE methods : data analysis; techniques : image processing; cosmic microwave background ID BEAST EXPERIMENT; SEPARATION; POLARIZATION; DESIGN; MAPS AB We present the angular power spectrum of the cosmic microwave background (CMB) component extracted with FASTICA from the Background Emission Anisotropy Scanning Telescope (BEAST) data. BEAST is a 2.2-m off-axis telescope with a focal plane comprising eight elements at Q (38-45 GHz) and Ka (26-36 GHz) bands. It operates from the UC (University of California) White Mountain Research Station at an altitude of 3800 m. The BEAST CMB angular power spectrum has already been calculated by O'Dwyer et al. using only the Q-band data. With two input channels, FASTICA returns two possible independent components. We found that one of these two has an unphysical spectral behaviour, while the other is a reasonable CMB component. After a detailed calibration procedure based on Monte Carlo (MC) simulations, we extracted the angular power spectrum for the identified CMB component and found a very good agreement with the already published BEAST CMB angular power spectrum and with the Wilkinson Microwave Anisotropy Probe (WMAP) data. C1 Univ Milan, Dipartimento Fis, I-20133 Milan, Italy. SISSA, ISAS, Astrophys Sector, I-34014 Trieste, Italy. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Fed Itajuba, Dept Quim & Fis, BR-37500903 Itajuba, MG, Brazil. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Jet Propuls Lab, Pasadena, CA 91109 USA. Inst Nacl Pesquisas Espaciais, Div Astrofis, BR-12245970 Sao Jose Dos Campos, SP, Brazil. RP Donzelli, S (reprint author), Univ Milan, Dipartimento Fis, Via Celoria 16, I-20133 Milan, Italy. EM simona.donzelli@mi.infn.it RI Figueiredo, Newton/F-9976-2011; OI WANDELT, Benjamin/0000-0002-5854-8269 NR 23 TC 7 Z9 7 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 JUN 11 PY 2006 VL 369 IS 1 BP 441 EP 448 DI 10.1111/j.1365-2966.2006.10320.x PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 046AI UT WOS:000237783400056 ER PT J AU Sun, XL Neumann, GA Abshire, JB Zuber, MT AF Sun, Xiaoli Neumann, Gregory A. Abshire, James B. Zuber, Maria T. TI Mars 1064 nm spectral radiance measurements determined from the receiver noise response of the Mars Orbiter Laser Altimeter SO APPLIED OPTICS LA English DT Article ID GLOBAL SURVEYOR MISSION; AVALANCHE PHOTODIODES; MOLA OBSERVATIONS AB A technique was developed to compute the radiance of the scene viewed by the optical receiver of the Mars Orbiter Laser Altimeter. The technique used the detection threshold and the false detection rate of the receiver to provide a passive radiometry measurement of Mars at the 1064 nm wavelength over a 2 mn bandwidth and subkilometer spatial resolution in addition to the altimetry and active radiometry measurements. The passive radiometry measurement is shown to have a 2% or better precision and has been stable over several Martian years. We describe the principle of operation of the instrument and its calibration and assess its performance from sample orbital measurements. (c) 2006 Optical Society of America. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. RP Sun, XL (reprint author), NASA, Goddard Space Flight Ctr, Code 694, Greenbelt, MD 20771 USA. EM xiaoli.sun-1@nasa.gov RI Sun, Xiaoli/B-5120-2013; Abshire, James/I-2800-2013; Neumann, Gregory/I-5591-2013 OI Neumann, Gregory/0000-0003-0644-9944 NR 20 TC 12 Z9 13 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUN 10 PY 2006 VL 45 IS 17 BP 3960 EP 3971 DI 10.1364/AO.45.003960 PG 12 WC Optics SC Optics GA 051ZH UT WOS:000238199700005 PM 16761033 ER PT J AU Trudeau, ME Chen, P Garcia, GD Hollberg, LW Tans, PP AF Trudeau, Michael E. Chen, Pin Garcia, Guilherme de Andrade Hollberg, Leo W. Tans, Pieter P. TI Stable isotopic analysis of atmospheric methane by infrared spectroscopy by use of diode laser difference-frequency generation SO APPLIED OPTICS LA English DT Article ID RATIO MEASUREMENT; HYDROGEN; CARBON AB An infrared absorption spectrometer has been constructed to measure the stable isotopic composition of atmospheric methane samples. The spectrometer employs periodically poled lithium niobate to generate 15 LW of tunable difference-frequency radiation from two near-infrared diode lasers that probe the nu(3) rotational-vibrational band of methane at 3.4 mu m. To enhance the signal, methane is extracted from 25 1 of air by use of a cryogenic chromatographic column and is expanded into the multipass cell for analysis. A measurement precision of 12 parts per thousand is demonstrated for both delta C-13 and delta D. (c) 2006 Optical Society of America. C1 NOAA, Earth Syst Res Lab, Hilo, HI 96720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Inst Nacl Metrol Normalizacao & Qualidade Ind, BR-25250020 Rio De Janeiro, Brazil. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80305 USA. NOAA, Earth Syst Res Lab, Boulder, CO 80303 USA. RP Trudeau, ME (reprint author), NOAA, Earth Syst Res Lab, POB 275, Hilo, HI 96720 USA. EM michael.trudeau@noaa.gov RI Chen, Pin/B-1112-2008; OI Chen, Pin/0000-0003-1195-9666; de Andrade Garcia, Guilherme/0000-0002-4740-8762 NR 14 TC 6 Z9 6 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUN 10 PY 2006 VL 45 IS 17 BP 4136 EP 4141 DI 10.1364/AO.45.004136 PG 6 WC Optics SC Optics GA 051ZH UT WOS:000238199700028 PM 16761056 ER PT J AU Leonhardt, V Camp, JB AF Leonhardt, Volker Camp, Jordan B. TI Space interferometry application of laser frequency stabilization with molecular iodine SO APPLIED OPTICS LA English DT Article AB A number of planned space interferometry missions, including the Laser Interferometer Space Antenna (LISA) gravitational wave detector, require a laser system with high-frequency stability over long time scales. A 1064 nm wavelength nonplanar ring oscillator (NPRO) laser stabilized to a resonant transition in molecular iodine is suitable for these missions, providing high-frequency stability at an absolute reference frequency. The iodine stabilized laser also offers low sensitivity to temperature and alignment fluctuations and allows frequency tuning. We have evaluated the noise performance of a NPRO laser stabilized to iodine using frequency modulation spectroscopy and have found an Allan standard deviation of 10(-14) over 100 s. Simplified optical configurations and the radiation hardness of the frequency-doubling crystals have also been investigated. (c) 2006 Optical Society of America. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. RP Leonhardt, V (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Code 663, Greenbelt, MD 20771 USA. EM volker@milkyway.gsfe.nasa.gov NR 15 TC 16 Z9 16 U1 0 U2 7 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUN 10 PY 2006 VL 45 IS 17 BP 4142 EP 4146 DI 10.1364/AO.45.004142 PG 5 WC Optics SC Optics GA 051ZH UT WOS:000238199700029 PM 16761057 ER PT J AU Brand, K Dey, A Weedman, D Desai, V Le Floc'h, E Jannuzi, BT Soifer, BT Brown, MJI Eisenhardt, P Gorjian, V Papovich, C Smith, HA Willner, SP Cool, RJ AF Brand, K Dey, A Weedman, D Desai, V Le Floc'h, E Jannuzi, BT Soifer, BT Brown, MJI Eisenhardt, P Gorjian, V Papovich, C Smith, HA Willner, SP Cool, RJ TI The active galactic nuclei contribution to the mid-infrared emission of luminous infrared galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : starburst; infrared : galaxies; X-rays ID SPITZER-SPACE-TELESCOPE; SPECTRAL ENERGY-DISTRIBUTIONS; X-RAY SURVEY; 1ST-LOOK SURVEY; SOURCE COUNTS; LOCKMAN HOLE; XBOOTES; DUST; COUNTERPARTS; QUASARS AB We determine the contribution of AGN to the mid-IR emission of luminous infrared galaxies (LIRGs) at z > 0.6 by measuring the mid-IR dust continuum slope of 20,039 mid-IR sources. The 24 mu m sources are selected from a Spitzer MIPS survey of the NOAO Deep Wide-Field Survey Bootes field and have corresponding 8 mu m data from the IRAC Shallow Survey. There is a clear bimodal distribution in the 24 to 8 mu m flux ratio. The X-ray-detected sources fall within the peak corresponding to a flat spectrum in nu f(nu), implying that it is populated by AGN-dominated LIRGs, whereas the peak corresponding to a higher 24 to 8 mu m flux ratio is likely due to LIRGs whose IR emission is powered by starbursts. The 24 mu m emission is increasingly dominated by AGN at higher 24 mu m flux densities (f(24)): the AGN fraction of the z > 0.6 sources increases from 9% at f(24) approximate to 0.35 mJy to 74% +/- 20% at f(24) approximate to 3 mJy, in good agreement with model predictions. Deep 24 mu m, small-area surveys, like GOODS, will be strongly dominated by starburst galaxies. AGN are responsible for similar to 3%-7% of the total 24 mu m background. C1 Natl Opt Astron Observ, Tucson, AZ 85726 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Associated Observ Paris, Galaxies Etoiles Phys & Instrumentat, F-92195 Meudon, France. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Brand, K (reprint author), Natl Opt Astron Observ, 950 N Cherry Ave, Tucson, AZ 85726 USA. EM brand@noao.edu RI Brown, Michael/B-1181-2015 OI Brown, Michael/0000-0002-1207-9137 NR 35 TC 81 Z9 81 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 JUN 10 PY 2006 VL 644 IS 1 BP 143 EP 147 DI 10.1086/503416 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XK UT WOS:000238339200012 ER PT J AU Morse, JA Smith, N Blair, WP Kirshner, RP Winkler, PF Hughes, JP AF Morse, Jon A. Smith, Nathan Blair, William P. Kirshner, Robert P. Winkler, P. Frank Hughes, John P. TI Hubble Space Telescope observations of oxygen-rich supernova remnants in the Magellanic Clouds. III. WFPC2 imaging of the young, crab-like supernova remnant SNR 0540-69.3 SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; ISM : individual (SNR 0540-69.3); Magellanic Clouds; supernova remnants ID CASSIOPEIA-A; CIRCUMSTELLAR RING; SYNCHROTRON NEBULA; OPTICAL-SPECTRUM; FAR-ULTRAVIOLET; PULSAR; SPECTROSCOPY; DISCOVERY; GEOMETRY; NITROGEN AB HST images with WFPC2 of the young, oxygen-rich, Crab-like supernova remnant SNR 0540-69.3 in the Large Magellanic Cloud (LMC) reveal details of the emission distribution and the relationship between the expanding ejecta and synchrotron nebula. The emission distributions appear very similar to those seen in the Crab Nebula, with the ejecta located in a thin envelope surrounding the synchrotron nebula. The [O III] emission is more extended than other tracers, forming a faint "skin" around the denser filaments and synchrotron nebula, as also observed in the Crab. The [O III] exhibits somewhat different kinematic structure in long-slit spectra, including a more extended high-velocity emission halo not seen in images. Yet even the fastest expansion speeds in SNR 0540-69.3's halo are slow when compared to most other young supernova remnants, although the Crab Nebula has similar slow expansion speeds. We show a striking correspondence between the morphology of the synchrotron nebula observed in an optical continuum filter with that recently resolved in Chandra X-ray images. We argue that the multicomponent kinematics and filamentary morphology of the optical emission-line features likely result from magnetic Rayleigh-Taylor instabilities that form as the synchrotron nebula expands and sweeps up ejecta, as seen in the Crab Nebula. Our images and spectra help to refine our understanding of SNR 0540-69.3 in several more detailed respects: they confirm the identification of H alpha + [N II] in the red spectrum, show that the systemic velocity of SNR 0540-69.3 is not significantly different from that of the LMC, and hint at a lower Ne abundance than the Crab (potentially indicating a more massive progenitor star). C1 NASA, Goddard Space Flight Ctr, Lab Observ Cosmol, Greenbelt, MD 20771 USA. Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Middlebury Coll, Dept Phys, Middlebury, VT 05753 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. RP Morse, JA (reprint author), NASA, Goddard Space Flight Ctr, Lab Observ Cosmol, Mail Code 665, Greenbelt, MD 20771 USA. EM jon.morse@nasa.gov; nathans@casa.colorado.edu; wpb@pha.jhu.edu; kirshner@cfa.harvard.edu; winkler@panther.middlebury.edu; jph@physics.rutgers.edu NR 38 TC 13 Z9 13 U1 0 U2 2 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 JUN 10 PY 2006 VL 644 IS 1 BP 188 EP 197 DI 10.1086/503313 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XK UT WOS:000238339200018 ER PT J AU Yusef-Zadeh, F Bushouse, H Dowell, CD Wardle, M Roberts, D Heinke, C Bower, GC Vila-Vilaro, B Shapiro, S Goldwurm, A Belanger, G AF Yusef-Zadeh, F. Bushouse, H. Dowell, C. D. Wardle, M. Roberts, D. Heinke, C. Bower, G. C. Vila-Vilaro, B. Shapiro, S. Goldwurm, A. Belanger, G. TI A multiwavelength study of SGR A*: The role of near-IR flares in production of X-ray, soft gamma-ray, and submillimeter emission SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; galaxies : nuclei; Galaxy : center ID SUPERMASSIVE BLACK-HOLE; SAGITTARIUS-A; GALACTIC-CENTER; ACCRETION FLOW; ELECTRON ACCELERATION; POLARIZED MILLIMETER; INFRARED FLARES; CENTRAL PARSEC; XMM-NEWTON; MILKY-WAY AB Although Sgr A* is known to be variable in radio, millimeter, near-IR, and X-rays, the correlation of the variability across its spectrum has not been fully studied. Here we describe highlights of the results of two observing campaigns in 2004 to investigate the correlation of flare activity in different wavelength regimes, using a total of nine ground- and space-based telescopes. We report the detection of several new near-IR flares during the campaign based on HST observations. The level of near-IR flare activity can be as low as similar to 0.15 mJy at 1.6 mu m and continuous up to similar to 40% of the total observing time, thus placing better limits than ground- based near-IR observations. Using HST NICMOS, XMM-Newton, and CSO, we also detect simultaneous bright X-ray and near-IR flare in which we observe for the first time correlated substructures as well as simultaneous submillimeter and near-IR flaring. X-ray emission is arising from the population of near-IR-synchrotron- emitting particles, which scatter submillimeter seed photons within the inner 10 Schwarzschild radii of Sgr A* up to X-ray energies. In addition, using the inverse Compton scattering picture, we explain the high-energy 20-120 keV emission from the direction toward Sgr A*, and the lack of one-to-one X-ray counterparts to near-IR flares, by the variation of the magnetic field and the spectral index distributions. In this picture, the evidence for the variability of submillimeter emission during a near-IR flare is produced by the low-energy component of the population of particles emitting synchrotron near-IR emission. Using the measurements of the duration of flares in near-IR and submillimeter wavelengths, we argue that the cooling could be due to adiabatic expansion with the implication that flare activity drives an outflow. C1 Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Macquarie Univ, Dept Phys, Sydney, NSW 2109, Australia. Adler Planetarium & Astron Museum, Chicago, IL 60605 USA. Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. Natl Observ Japan, Tokyo 1818588, Japan. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. Astroparticle & Cosmol, F-75005 Paris, France. RP Yusef-Zadeh, F (reprint author), Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. EM zadeh@northwestern.edu; bushouse@stsci.edu; cdd@submm.caltech.edu; wardle@physics.mq.edu.au; doug-roberts@northwestern.edu; cheinke@northwestern.edu; gbower@astron.berkeley.edu; vila.vilaro@nao.ac.jp; shapiro@astro.physics.uiuc.edu; goldwurm@discovery.saclay.cea.fr; belanger@cea.fr NR 56 TC 89 Z9 89 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 JUN 10 PY 2006 VL 644 IS 1 BP 198 EP 213 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XK UT WOS:000238339200019 ER PT J AU Laming, JM Hwang, U Radics, B Lekli, G Takacs, E AF Laming, J. Martin Hwang, Una Radics, Balint Lekli, Gergely Takacs, Endre TI The polar regions of Cassiopeia A: The aftermath of a gamma-ray burst? SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; ISM : jets and outflows; supernova remnants; supernovae : individual (Cassiopeia A) ID DIELECTRONIC RECOMBINATION DATA; FINITE-DENSITY PLASMAS; CORE-COLLAPSE SUPERNOVA; ISOELECTRONIC SEQUENCE; EMISSION-LINES; MASSIVE STARS; NONLINEAR AMPLIFICATION; RELATIVISTIC JETS; RATE COEFFICIENTS; IB/C SUPERNOVAE AB Are the polar regions of Cas A the aftermath of a gamma-ray burst? Probably not, but it is interesting nevertheless to investigate just how close Cas A might have come to generating such an event. Focusing on the northeast jet filaments, we analyze the polar regions of the recently acquired very deep 1 Ms Chandra X-ray observation. We infer that the so-called "jet" regions are indeed due to jets emanating from the explosion center and not due to polar cavities in the circumstellar medium at the time of explosion. We place limits on the equivalent isotropic explosion energy in the polar regions (around 2: 3; 1052 ergs) and the opening angle of the X-ray-emitting ejecta (around 7 degrees), which give a total energy in the northeast jet of the order of 1050 ergs, an order of magnitude or more lower than inferred for "typical" GRBs. While the Cas A progenitor and explosion exhibit many of the features associated with GRB hosts, e.g., extensive presupernova mass loss and rotation and jets associated with the explosion, we speculate that the recoil of the compact central object, with a velocity of 330 km s(-1), may have rendered the jet unstable. In such cases the jet rapidly becomes baryon loaded, if not truncated altogether. Although unlikely to have produced a gamma-ray burst, the jets in Cas A suggest that such outflows may be common features of core-collapse SNe. C1 USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Debrecen, Inst Expt Phys, H-4026 Debrecen, Hungary. RP Laming, JM (reprint author), USN, Res Lab, EO Hulburt Ctr Space Res, Code 7674L, Washington, DC 20375 USA. EM laming@nrl.navy.mil; hwang@orfeo.gsfc.nasa.gov OI Radics, Balint/0000-0002-8978-1725 NR 87 TC 34 Z9 34 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 JUN 10 PY 2006 VL 644 IS 1 BP 260 EP 273 DI 10.1086/503553 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XK UT WOS:000238339200022 ER PT J AU Kaufman, MJ Wolfire, MG Hollenbach, DJ AF Kaufman, Michael J. Wolfire, Mark. G. Hollenbach, David J. TI [Si II], [Fe II], [C II], and H(2) emission from massive star-forming regions SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : ISM; infrared : ISM; ISM : atoms; ISM : lines and bands; ISM : molecules ID PHOTON-DOMINATED REGIONS; PHOTODISSOCIATION REGIONS; INTERSTELLAR-MEDIUM; PHYSICAL CONDITIONS; MOLECULAR-HYDROGEN; LINE EMISSION; ULTRAVIOLET-RADIATION; NGC 2023; GALAXIES; CLOUDS AB We calculate the [Si II] 34.8 mu m, [Fe II] 26.0 mu m, and [C II] 158 mu m infrared fine-structure emission that may arise from ionized gas (H II regions) and/or associated neutral gas (photodissociation regions [PDRs]) in massive star-forming regions. Assuming thermal pressure balance between an H II region and a PDR, the relative amounts of fine-structure line emission from the H II region and PDR depend on the electron density and resulting thermal pressure in the H II region, gas-phase abundances of the emitting species, and the UV spectrum from the stellar population producing the H II region. For normal metallicity, we find that [C II] emission is always dominated by PDRs, while [Si II] and [Fe II] are dominated by PDRs for H II regions with electron density n(e) greater than or similar to 10 cm(-3). We also calculate the H(2) 0-0 S(0), 0-0 S(1), 0-0 S(2), and 0-0 S(3) pure rotational line emission arising from the PDR at the atomic-to-molecular interface. The overall intensity of the H(2) line emission directly traces warm molecular mass, while H(2) line ratios constrain the PDR temperature, gas density, and far-ultraviolet field strength. Models of the integrated emission of [Si II], [Fe II], [C II], and H(2) from Galactic and extragalactic star-forming regions are presented for use in interpreting observations with Spitzer, ISO, SOFIA, and the Herschel Space Observatory. We compare our results with observations of the Galactic source NGC 2023 (an individual H II/photodissociation region in Orion), the inner regions of the Milky Way, and the central regions of the nearby star-forming spiral galaxy NGC 7331. We also compare our results with recently published similar work by Abel and coworkers. C1 San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. NASA, Ames Res Ctr, Space Sci & Astrobiol Div, Moffett Field, CA 94035 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Kaufman, MJ (reprint author), San Jose State Univ, Dept Phys, 1 Washington Sq, San Jose, CA 95192 USA. NR 54 TC 113 Z9 114 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 JUN 10 PY 2006 VL 644 IS 1 BP 283 EP 299 DI 10.1086/503596 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XK UT WOS:000238339200025 ER PT J AU Harvey, PM Chapman, N Lai, SP Evans, NJ Allen, LE Jorgensen, JK Mundy, LG Huard, TL Porras, A Cieza, L Myers, PC Merin, B van Dishoeck, EF Young, KE Spiesman, W Blake, GA Koerner, DW Padgett, DL Sargent, AI Stapelfeldt, KR AF Harvey, Paul M. Chapman, Nicholas Lai, Shih-Ping Evans, Neal J., II Allen, Lori E. Jorgensen, Jes K. Mundy, Lee G. Huard, Tracy L. Porras, Alicia Cieza, Lucas Myers, Philip C. Merin, Bruno van Dishoeck, Ewine F. Young, Kaisa E. Spiesman, William Blake, Geoffrey A. Koerner, David W. Padgett, Deborah L. Sargent, Anneila I. Stapelfeldt, Karl R. TI The Spitzer c2d survey of large, nearby, insterstellar clouds. II. Serpens observed with IRAC SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : ISM; ISM : clouds ID YOUNG STELLAR OBJECTS; HERBIG AE/BE STARS; LARGE-MAGELLANIC-CLOUD; MAIN-SEQUENCE STARS; MOLECULAR CLOUD; INFRARED OBSERVATIONS; OPHIUCHI CLOUD; CORE; EMISSION; MICRON AB We present maps of 0.89 deg(2) of the Serpens dark cloud at 3.6, 4.5, 5.8, and 8.0 mu m observed with the Spitzer Space Telescope Infrared Array Camera (IRAC). We discuss in detail the data processing carried out by the c2d team on IRAC data. More than 100,000 compact sources have been extracted, but we confine most of our discussion to the most reliable subset of these sources. This includes those that are detected above 7 sigma in all four IRAC bands or those detected in the two shorter IRAC bands together with 2MASS. We estimate completeness limits for our survey from Monte Carlo tests with artificial sources inserted into the Spitzer maps. We compare source counts, colors, and magnitudes in the Serpens cloud to two reference data sets, a 0.10 deg(2) set of low-extinction regions near the dark cloud and a 1 deg(2) subset of the SWIRE Elais N1 data that was processed through our pipeline. We find that it is possible to identify more than 200 young stellar object (YSO) candidates from color-magnitude and color-color diagrams, most of which were previously unknown. In addition to the dense area of new star formation known before in the "core'' region ( cluster A), we also find a moderately rich area to the south ( cluster B). Our mapped area also includes the Herbig Ae star VV Ser, whose Spitzer images have been carefully modeled in a separate study. The extreme sensitivity of Spitzer IRAC allows us to search to very low luminosity limits for young substellar objects. The comparison of the Serpens region with the reference areas suggests that a population of infrared excess sources exists in Serpens at least down to luminosities of L similar to 10(-3) L(.) and possibly lower. C1 Univ Texas, Dept Astron, Austin, TX 78712 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Leiden Observ, NL-2300 RA Leiden, Netherlands. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. No Arizona Univ, Dept Phys & Astron, Flagstaff, AZ 86011 USA. Spitzer Sci Ctr, Pasadena, CA 91125 USA. CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Harvey, PM (reprint author), Univ Texas, Dept Astron, 1 Univ Stn C1400, Austin, TX 78712 USA. EM pmh@astro.as.utexas.edu; chapman@astro.umd.edu; slai@astro.umd.edu; nje@astro.as.utexas.edu; leallen@cfa.harvard.edu; jjorgensen@cfa.harvard.edu; lgm@astro.umd.edu; thuard@cfa.harvard.edu; aporras@cfa.harvard.edu; lcieza@astro.as.utexas.edu; pmyers@cfa.harvard.edu; merin@strw.leidenuniv.nl; ewin@strw.leidenuniv.nl; kaisa@astro.as.utexas.edu; spies@astro.as.utexas.edu; gab@gps.caltech.edu; koerner@physics.nau.edu; dlp@ipac.caltech.edu; afs@astro.caltech.edu; krs@exoplanet.jpl.nasa.gov RI Stapelfeldt, Karl/D-2721-2012 NR 46 TC 115 Z9 115 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 JUN 10 PY 2006 VL 644 IS 1 BP 307 EP 325 DI 10.1086/503520 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XK UT WOS:000238339200027 ER PT J AU Band, DL AF Band, DL TI Postlaunch analysis of Swift's gamma-ray burst detection sensitivity SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; instrumentation : detectors ID BATSE OBSERVATIONS; ALERT TELESCOPE; MISSION; SPECTRA AB The dependence of Swift's detection sensitivity on a burst's temporal and spectral properties shapes the detected burst population. Using simplified models of the detector hardware and the burst trigger system, I find that Swift is more sensitive to long, soft bursts than CGRO's BATSE, a reference detector because of the large burst database it has accumulated. Swift has increased sensitivity in the parameter space region into which time dilation and spectral redshifting move high-redshift bursts. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Dept Phys, Joint Ctr Astrophys, Baltimore, MD 21250 USA. RP Band, DL (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 18 TC 74 Z9 74 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 JUN 10 PY 2006 VL 644 IS 1 BP 378 EP 384 DI 10.1086/503326 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XK UT WOS:000238339200032 ER PT J AU Reig, P Papadakis, IE Shrader, CR Kazanas, D AF Reig, P Papadakis, IE Shrader, CR Kazanas, D TI Fourier-resolved spectroscopy of 4U 1543-47 during the 2002 outburst SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; stars : individual (4U 1543-47); X-rays : binaries; X-rays : stars ID QUASI-PERIODIC OSCILLATIONS; TRANSIENT 4U 1543-47; X-RAY REFLECTION; BLACK-HOLE; FAST VARIABILITY; GRS 1915+105; HIGH STATE; CYG X-1; TENMA; NOISE AB We have obtained Fourier-resolved spectra of the black hole binary 4U 1543-47 in the canonical states (high/soft, very high, intermediate, and low/hard) observed in this source during the decay of an outburst that took place in 2002. Our objective is to investigate the variability of the spectral components generally used to describe the energy spectra of black hole systems, namely a disk component, a power-law component attributed to Comptonization by a hot corona, and the contribution of the iron line due to reprocessing of the high-energy ( E greater than or similar to 7 keV) radiation. We find that ( 1) the disk component is not variable on timescales shorter than similar to 100 s, ( 2) the reprocessing emission as manifest by the variability of the FeK alpha line responds to the primary radiation variations down to timescales of similar to 70 ms in the high and very high states, but longer than 2 s in the low state, ( 3) the low-frequency QPOs are associated with variations of the X-ray power-law spectral component and not to the disk component, and ( 4) the spectra corresponding to the highest Fourier frequency are the hardest ( show the flatter spectra) at a given spectral state. These results question models that explain the observed power spectra as due to modulations of the accretion rate alone, as such models do not provide any apparent reason for a Fourier frequency dependence of the power-law spectral indices. C1 Fdn Res & Technol, IESL, Iraklion 71110, Crete, Greece. Univ Crete, Dept Phys, Iraklion 71003, Crete, Greece. NASA, Explorat Universe Div, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Reig, P (reprint author), Fdn Res & Technol, IESL, Iraklion 71110, Crete, Greece. EM pau@physics.uoc.gr; jhep@physics.uoc.gr; chris.r.shrader@gsfc.nasa.gov; demos.kazanas-1@nasa.gov RI Papadakis, Iossif/C-3235-2011; Reig, Pablo/A-1198-2014 OI Reig, Pablo/0000-0002-6446-3050 NR 28 TC 11 Z9 11 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 JUN 10 PY 2006 VL 644 IS 1 BP 424 EP 431 DI 10.1086/503356 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XK UT WOS:000238339200036 ER PT J AU Winn, JN Hamilton, CM Herbst, WJ Hoffman, JL Holman, MJ Johnson, JA Kuchner, MJ AF Winn, JN Hamilton, CM Herbst, WJ Hoffman, JL Holman, MJ Johnson, JA Kuchner, MJ TI The orbit and occultations of KH 15D SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; open clusters and associations : individual (NGC 2264) stars : individual (KH 15D); stars : pre-main-sequence ID T-TAURI STARS; LOW-MASS STARS; NGC 2264; MYSTERIOUS ECLIPSES; LIGHT CURVES; SYSTEM; BINARY; SPECTROSCOPY; PHOTOMETRY; EMISSION AB The unusual flux variations of the pre-main-sequence binary star KH 15D have been attributed to occultations by a circumbinary disk. We test whether or not this theory is compatible with newly available data, including recent radial velocity measurements, CCD photometry over the past decade, and photographic photometry over the past 50 years. We find the model to be successful, after two refinements: a more realistic motion of the occulting feature and a halo around each star that probably represents scattering by the disk. The occulting feature is exceptionally sharp edged, raising the possibility that the dust in the disk has settled into a thin layer and providing a tool for fine-scale mapping of the immediate environment of a T Tauri star. However, the window of opportunity is closing, as the currently visible star may be hidden at all orbital phases by as early as 2008. C1 MIT, Dept Phys, Cambridge, MA 02139 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Mt Holyoke Coll, Dept Astron, S Hadley, MA 01075 USA. Univ Massachusetts, Five Coll Astron Dept, Amherst, MA 01003 USA. Wesleyan Univ, Van Vleck Observ, Middletown, CT 06459 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Winn, JN (reprint author), MIT, Dept Phys, 77 Massachusetts Ave, Cambridge, MA 02139 USA. RI Kuchner, Marc/E-2288-2012 NR 49 TC 30 Z9 31 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 JUN 10 PY 2006 VL 644 IS 1 BP 510 EP 524 DI 10.1086/503417 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XK UT WOS:000238339200045 ER PT J AU Moor, A Abraham, P Derekas, A Kiss, C Kiss, LL Apai, D Grady, C Henning, T AF Moor, A Abraham, P Derekas, A Kiss, C Kiss, LL Apai, D Grady, C Henning, T TI Nearby debris disk systems with high fractional luminosity reconsidered SO ASTROPHYSICAL JOURNAL LA English DT Review DE circumstellar matter; infrared : stars; stars : kinematics ID MAIN-SEQUENCE STARS; VEGA-LIKE STARS; SPITZER-SPACE-TELESCOPE; TW HYDRAE ASSOCIATION; SOLAR-TYPE STARS; MULTIBAND IMAGING PHOTOMETER; STELLAR KINEMATIC GROUPS; LOW-MASS STARS; YOUNG STARS; BETA-PICTORIS AB By searching the IRAS and ISO databases, we compiled a list of 60 debris disks that exhibit the highest fractional luminosity values (f(d) > 10(-4)) in the vicinity of the Sun ( d < 120 pc). Eleven out of these 60 systems are new discoveries. Special care was taken to exclude bogus disks from the sample. We computed the fractional luminosity values using available IRAS, ISO, and Spitzer data and analyzed the Galactic space velocities of the objects. The results revealed that stars with disks of high fractional luminosity often belong to young stellar kinematic groups, providing an opportunity to obtain improved age estimates for these systems. We found that practically all disks with f(d) > 5 x 10(-4) are younger than 100 Myr. The distribution of the disks in the fractional luminosity versus age diagram indicates that ( 1) the number of old systems with high fd is lower than was claimed before, ( 2) there exist many relatively young disks of moderate fractional luminosity, and ( 3) comparing the observations with a current theoretical model of debris disk evolution, a general good agreement could be found. C1 Hungarian Acad Sci, Konkoly Observ, H-1525 Budapest, Hungary. Univ Sydney, Sch Phys A28, Sydney, NSW 2006, Australia. Univ New S Wales, Sch Phys, Dept Astrophys & Opt, Sydney, NSW 2052, Australia. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. NASA, Astrobiol Inst, Washington, DC 20546 USA. Eureka Sci, Oakland, CA 94602 USA. NASA, Goddard Space Flight Ctr, Exo Planets & Stellar Astrophys Lab, Explorat Universe Div, Greenbelt, MD 20771 USA. Max Planck Inst Astron, D-69117 Heidelberg, Germany. RP Moor, A (reprint author), Hungarian Acad Sci, Konkoly Observ, POB 67, H-1525 Budapest, Hungary. RI Kiss, Laszlo/A-2539-2008; Derekas, Aliz/G-2091-2016 OI Derekas, Aliz/0000-0002-6526-9444 NR 121 TC 135 Z9 135 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 JUN 10 PY 2006 VL 644 IS 1 BP 525 EP 542 DI 10.1086/503381 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XK UT WOS:000238339200046 ER PT J AU Haghighipour, N AF Haghighipour, N TI Dynamical stability and habitability of the gamma Cephei binary-planetary system SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; celestial mechanics; planetary systems; planets and satellites : general; solar system : general ID ELLIPTIC RESTRICTED PROBLEM; ALPHA-CENTAURI SYSTEM; CARBON-DIOXIDE CLOUDS; STAR SYSTEMS; 3-BODY SYSTEMS; GIANT PLANET; GG TAURI; ORBITS; CONSTRAINTS; INSTABILITY AB It has been suggested that the long-lived residual radial velocity variations observed in the precision radial velocity measurements of the primary of gamma Cephei (HR 8974, HD 222404, HIP 116727) are likely due to a Jupiter-like planet orbiting this star. In this paper, the dynamics of this planet is studied, and the possibility of the existence of a terrestrial planet around its central star is discussed. Simulations, which have been carried out for different values of the eccentricity and semimajor axis of the binary, as well as the orbital inclination of its Jupiter-like planet, expand on previous studies of this system and indicate that, for the values of the binary eccentricity smaller than 0.5, and for all values of the orbital inclination of the Jupiter-like planet ranging from 0 degrees to 40 degrees, the orbit of this planet is stable. For larger values of the binary eccentricity, the system becomes gradually unstable. Integrations also indicate that, within this range of orbital parameters, a terrestrial planet, such as an Earth-like object, can have a long-term stable orbit only at distances of 0.3 - 0.8 AU from the primary star. The habitable zone of the primary, at a range of approximately 3.05 - 3.7 AU, is, however, unstable. C1 Univ Hawaii Manoa, Inst Astron, Honolulu, HI 96822 USA. Univ Hawaii Manoa, NASA Astrobiol Inst, Honolulu, HI 96822 USA. RP Haghighipour, N (reprint author), Univ Hawaii Manoa, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. EM nader@ifa.hawaii.edu NR 55 TC 40 Z9 40 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 JUN 10 PY 2006 VL 644 IS 1 BP 543 EP 550 DI 10.1086/503351 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XK UT WOS:000238339200047 ER PT J AU Turnbull, MC Traub, WA Jucks, KW Woolf, NJ Meyer, MR Gorlova, N Skrutskie, MF Wilson, JC AF Turnbull, MC Traub, WA Jucks, KW Woolf, NJ Meyer, MR Gorlova, N Skrutskie, MF Wilson, JC TI Spectrum of a habitable world: Earthshine in the near-infrared SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrobiology; Earth; Moon; planetary systems ID EXTRASOLAR TERRESTRIAL PLANETS; CLOUDS; SATELLITES; SURFACES; DISK; ICE AB To characterize the spectrum of Earth viewed as an extrasolar planet, we observed the spatially integrated near-infrared (0.7 - 2.4 mu m) reflection spectrum of Earth via the dark side of the Moon (earthshine). After contributions from the Sun, Moon, and local atmosphere were removed, the resulting spectrum was fitted with a simple model of the reflectivity of Earth. The best model fit is dominated by the reflection spectrum of the atmosphere above medium-altitude water clouds, with lesser contributions from high-altitude ice clouds and from the ground. The spectral features seen are H2O ( six strong band structures from 0.7 to 2.0 mu m), CO2 (six moderate-strength features from 1.4 to 2.1 mu m), O-2 (two moderate-strength features at 0.76 and 1.26 mu m), and several weak CH4 features. Interpreted as a spectrum of an extrasolar planet, we would confidently conclude that this is a habitable planet, based on the presence of strong water bands. Furthermore, the simultaneous presence of oxygen and methane is a strong indicator of biological activity. We might also conclude that the planet is geologically active, based on the presence of CO2, water, and a dynamic atmosphere ( inferred from cirrus clouds, cumulus clouds, and clear-air fractions in our model fit). This suggests that it would be valuable for the Terrestrial Planet Finder - Coronagraph (TPF-C) mission to include near-infrared spectroscopy capability. On the basis of the present work, we suggest that future long-term monitoring of the earthshine would allow us to discern how the globally integrated spectrum changes with planet rotation, cloud cover, and seasons. C1 Carnegie Inst Washington, Washington, DC 20008 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. RP Turnbull, MC (reprint author), Carnegie Inst Washington, 5241 Broad Branch Rd, Washington, DC 20008 USA. EM turnbull@dtm.ciw.edu; wtraub@jpl.nasa.gov NR 27 TC 68 Z9 68 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 JUN 10 PY 2006 VL 644 IS 1 BP 551 EP 559 DI 10.1086/503322 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XK UT WOS:000238339200048 ER PT J AU Deming, D Harrington, J Seager, S Richardson, LJ AF Deming, D Harrington, J Seager, S Richardson, LJ TI Strong infrared emission from the extrasolar planet HD 189733b SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : general; planetary systems; stars : individual (HD 189733) ID SPITZER-SPACE-TELESCOPE; THERMAL EMISSION; HOT JUPITERS; PHOTOSPHERE; 209458B; SEARCH; STAR AB We report detection of strong infrared thermal emission from the nearby (d = 19 pc) transiting extrasolar planet HD 189733b by measuring the flux decrement during its prominent secondary eclipse. A 6 hr photometric sequence using Spitzer's infrared spectrograph in peak-up imaging mode at 16 mu m shows the secondary eclipse depth to be 0.551% +/- 0.030%, with accuracy limited by instrumental baseline uncertainties, but with 32 sigma precision (sigma = 0.017%) on the detection. The 16 mu m brightness temperature of this planet ( 1117 +/- 42 K) is very similar to the Spitzer detections of TrES-1 and HD 209458b, but the observed planetary flux ( 660 mu Jy) is an order of magnitude greater. This large signal will allow a detailed characterization of this planet in the infrared. Our photometry has sufficient signal-to-noise ratio ( similar to 400 per point) to motivate a search for structure in the ingress/egress portions of the eclipse curve, caused by putative thermal structure on the disk of the planet. We show that by binning our 6 s sampling down to similar to 6 minute resolution, we detect the modulation in the intensity derivative during ingress/egress due to the overall shape of the planet, but our sensitivity is not yet sufficient to distinguish between realistic models of the temperature distribution across the planet's disk. We point out the potential for extending Spitzer secondary eclipse detections down to the regime of transiting hot Neptunes, if such systems are discovered among nearby lower main-sequence stars. C1 NASA, Goddard Space Flight Ctr, Planetary Syst Lab, Greenbelt, MD 20771 USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. NASA, Goddard Space Flight Ctr, Exoplanets & Stellar Astrophys Lab, Greenbelt, MD 20771 USA. RP Deming, D (reprint author), NASA, Goddard Space Flight Ctr, Planetary Syst Lab, Mail Code 693, Greenbelt, MD 20771 USA. EM ddeming@pop600.gsfc.nasa.gov; jh@oobleck.astro.cornell.edu; seager@dtm.ciw.edu; richardsonlj@milkyway.gsfc.nasa.gov RI Harrington, Joseph/E-6250-2011; OI Harrington, Joseph/0000-0002-8955-8531 NR 19 TC 173 Z9 173 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 JUN 10 PY 2006 VL 644 IS 1 BP 560 EP 564 DI 10.1086/503358 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XK UT WOS:000238339200049 ER PT J AU Hathaway, DH Williams, PE Cuntz, M AF Hathaway, DH Williams, PE Cuntz, M TI Supergranule superrotation identified as a projection effect SO ASTROPHYSICAL JOURNAL LA English DT Article DE convection; Sun : helioseismology; Sun : photosphere; Sun : rotation; turbulence; waves ID MICHELSON DOPPLER IMAGER; SPHERICAL HARMONIC-ANALYSIS; STEADY PHOTOSPHERIC FLOWS; WAVE-LIKE PROPERTIES; SOLAR SUPERGRANULATION; ANGULAR VELOCITY; ROTATION; FEATURES; FIELDS AB Previous measurements of the rotation rate of the supergranule Doppler velocity pattern revealed surprising characteristics: ( 1) the pattern rotates faster than the plasma at the surface, and, at each latitude, it rotates faster than the plasma at any level below the surface (superrotation), ( 2) larger cells rotate more rapidly than smaller cells, and ( 3) faster rotation rates are found when using cross-correlation techniques with larger time lags between Doppler images. We simulate the supergranulation velocity pattern using a spectrum for the cellular flows that matches the observed spectrum, but we keep the pattern unchanged and rotating rigidly. Our simulation shows that the superrotation and its dependence on cell size can be largely reproduced by projection effects on the line-of-sight Doppler velocity signal. The remaining variation in rotation rate with cell size can be attributed to cells smaller than super-granules extending through shallower layers that have slower rotation rates. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Texas, Dept Phys, Arlington, TX 76019 USA. RP Hathaway, DH (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM david.hathaway@nasa.gov; pwilliams@uta.edu; cuntz@uta.edu NR 21 TC 18 Z9 18 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 JUN 10 PY 2006 VL 644 IS 1 BP 598 EP 602 DI 10.1086/498842 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XK UT WOS:000238339200054 ER PT J AU Burlaga, LF Vinas, AF Ness, NF Acuna, MH AF Burlaga, LF Vinas, AF Ness, NF Acuna, MH TI Tsallis statistics of the magnetic field in the heliosheath SO ASTROPHYSICAL JOURNAL LA English DT Article DE magnetic fields; solar wind; turbulence; waves ID TERMINATION SHOCK; VOYAGER-1; MECHANICS; REGION; AU AB The spacecraft Voyager 1 crossed the termination shock on 2004 December 16 at a distance of 94 AU from the Sun, and it has been moving through the heliosheath toward the interstellar medium since then. The distributions of magnetic field strength B observed in the heliosheath are Gaussian over a wide range of scales, yet the measured profile appears to be filamentary with occasional large jumps in the magnetic field strength. All of the B(t) probability distributions of changes in B, dBn - B(t + tau) - B(t) on scales tau from 1 to 128 days, can be fit with the symmetric Tsallis distribution of nonextensive statistical mechanics. At scales >= 32 days, the distributions are Gaussian, but on scales from 1 through 16 days the probability distribution functions have non-Gaussian tails, suggesting that the inner heliosheath is not in statistical equilibrium on scales from 1 to 16 days. C1 NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Greenbelt, MD 20771 USA. Catholic Univ Amer, Inst Astrophys & Computat Sci, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Planetary Magnetospheres Lab, Greenbelt, MD 20771 USA. RP Burlaga, LF (reprint author), NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Code 612-2, Greenbelt, MD 20771 USA. EM leonard.f.burlaga@nasa.gov; nfnudel@yahoo.edu; mario.h.acuna@nasa.gov NR 19 TC 38 Z9 39 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 JUN 10 PY 2006 VL 644 IS 1 BP L83 EP L86 DI 10.1086/505577 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XM UT WOS:000238339400021 ER PT J AU Hurford, GJ Krucker, S Lin, RP Schwartz, RA Share, GH Smith, DM AF Hurford, G. J. Krucker, S. Lin, R. P. Schwartz, R. A. Share, G. H. Smith, D. M. TI Gamma-ray imaging of the 2003 October/November solar flares SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : observations; Sun : flares; Sun : X-rays, gamma rays ID RECONNECTING CURRENT SHEETS; PARTICLE-ACCELERATION; ENERGY PARTITION; RHESSI; SPECTROSCOPY; EVENTS AB We present RHESSI imaging of three flares (2003 October 28 and 29 and November 2) in the 2.223 MeV neutron-capture gamma-ray line with angular resolution as high as 35 ''. Comparisons of imaged and spatially integrated fluences show that in all cases most, if not all, of the emission was confined to compact sources with size scales of tens of arcseconds or smaller that are located within the flare active region. Thus, the gamma-ray-producing ions appear to be accelerated by the flare process and not by a widespread shock driven by a fast coronal mass ejection. The 28 October event yielded the first such image to show double-footpoint gamma-ray line sources. These footpoint sources straddled the flaring loop arcade but were displaced from the corresponding 0.2-0.3 MeV electron-bremsstrahlung emission footpoints by 14 '' and 17 '' +/- 5 ''. As with the previously studied 2002 July 23 event, this implies spatial differences in acceleration and/or propagation between the flare-accelerated ions and electrons. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. USN, Res Lab, Washington, DC 20375 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA. Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA. RP Hurford, GJ (reprint author), Univ Calif Berkeley, Space Sci Lab, 7 Gauss Way, Berkeley, CA 94720 USA. EM ghurford@ssl.berkeley.edu; krucker@ssl.berkeley.edu; rlin@ssl.berkeley.edu; richard.schwartz@gsfc.nasa.gov; gerald.share@nrl.navy.mil; dsmith@scipp.ucsc.edu NR 25 TC 73 Z9 73 U1 0 U2 5 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 JUN 10 PY 2006 VL 644 IS 1 BP L93 EP L96 DI 10.1086/505329 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XM UT WOS:000238339400023 ER PT J AU Shuping, RY Kassis, M Morris, M Smith, N Bally, J AF Shuping, RY Kassis, M Morris, M Smith, N Bally, J TI Silicate emission profiles from low-mass protostellar disks in the Orion Nebula: Evidence for growth and thermal processing of grains SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; planetary systems : protoplanetary disks; stars : formation; stars : pre-main-sequence ID T-TAURI STARS; PROTOPLANETARY DISKS; CIRCUMSTELLAR DISKS; SOLAR-SYSTEM; DUST GRAINS; PHOTOEVAPORATION; MINERALOGY; PARTICLES; EVOLUTION; REGIONS AB We present 8-13 mu m low-resolution spectra (R approximate to 100) of eight low-mass protostellar objects ("proplyds") in the Orion Nebula using the Long Wavelength Spectrometer at the W. M. Keck Observatory. All but one of the sources in our sample show strong circumstellar silicate emission, with profiles that are qualitatively similar to those seen in some T Tauri and Herbig Ae/Be stars. The silicate profile in all cases is significantly flattened compared with the profile for typical interstellar dust, suggesting that the dominant emitting grains are significantly larger than those found in the interstellar medium. The 11.3-to-9.8 mu m flux ratio - often used as an indicator of grain growth - is in the 0.8-1.0 range for all of our targets, indicating that the typical grain size is around a few microns in the surface layers of the attendant circumstellar disk for each object. Furthermore, the silicate profiles show some evidence of crystalline features, as seen in other young stellar objects. The results of our analysis show that the grains in the photoevaporating protostellar disks of Orion have undergone significant growth and perhaps some annealing, suggesting that grain evolution for these objects is not qualitatively different from other young stellar objects. C1 NASA, Ames Res Ctr, Univ Space Res Assoc, Moffett Field, CA 90035 USA. WM Keck Observ, Kamuela, HI 96743 USA. Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA. Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. RP Shuping, RY (reprint author), NASA, Ames Res Ctr, Univ Space Res Assoc, Mail Stop 211-3, Moffett Field, CA 90035 USA. EM rshuping@sofia.usra.edu; mkassis@keck.hawaii.edu; morris@astro.ucla.edu; nathans@casa.colorado.edu; bally@origins.colorado.edu NR 35 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 JUN 10 PY 2006 VL 644 IS 1 BP L71 EP L74 DI 10.1086/505425 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XM UT WOS:000238339400018 ER PT J AU Sun, YZ Wang, ZJ Liu, Y AF Sun, YZ Wang, ZJ Liu, Y TI Spectral (finite) volume method for conservation laws on unstructured grids VI: Extension to viscous flow SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE high-order; unstuctured grid; spectral finite volume; Navier-Stokes equations ID ESSENTIALLY NONOSCILLATORY SCHEMES; DISCONTINUOUS GALERKIN METHOD; ONE-DIMENSIONAL SYSTEMS; ELEMENT-METHOD; DIFFUSION-PROBLEMS; FORMULATIONS; EQUATIONS; SCALAR; MESHES AB In this paper, the spectral volume (SV) method is extended to solve viscous flow governed by the Navier-Stokes equations. Several techniques to discretize the Viscous fluxes have been tested, and a formulation similar to the local discontinuous Galerkin (DG) approach developed for the DG method has been selected in the present Study. The SV method combines two key ideas, which are the bases of the finite volume and the finite element methods, i.e., the physics of wave propagation accounted for by the use of a Riemann solver and high-order accuracy achieved through high-order polynomial reconstructions within spectral volumes. The formulation of the SV method for a 2D advection-diffusion equation and the compressible Navier-Stokes equations is described. Accuracy studies are performed using problems with analytical solutions. The solver is used to compute laminar viscous flow problems to shown its potential. (c) 2005 Elsevier Inc. All rights reserved. C1 Iowa State Univ, Dept Aerosp Engn, Coll Engn, Ames, IA 50011 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Iowa State Univ, Dept Aerosp Engn, Coll 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 34 TC 63 Z9 66 U1 0 U2 6 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD JUN 10 PY 2006 VL 215 IS 1 BP 41 EP 58 DI 10.1016/j.jcp.2005.10.019 PG 18 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 035LH UT WOS:000237002000004 ER PT J AU Dils, B De Maziere, M Muller, JF Blumenstock, T Buchwitz, M de Beek, R Demoulin, P Duchatelet, P Fast, H Frankenberg, C Gloudemans, A Griffith, D Jones, N Kerzenmacher, T Kramer, I Mahieu, E Mellqvist, J Mittermeier, RL Notholt, J Rinsland, CP Schrijver, H Smale, D Strandberg, A Straume, AG Stremme, W Strong, K Sussmann, R Taylor, J van den Broek, M Velazco, V Wagner, T Warneke, T Wiacek, A Wood, S AF Dils, B De Maziere, M Muller, JF Blumenstock, T Buchwitz, M de Beek, R Demoulin, P Duchatelet, P Fast, H Frankenberg, C Gloudemans, A Griffith, D Jones, N Kerzenmacher, T Kramer, I Mahieu, E Mellqvist, J Mittermeier, RL Notholt, J Rinsland, CP Schrijver, H Smale, D Strandberg, A Straume, AG Stremme, W Strong, K Sussmann, R Taylor, J van den Broek, M Velazco, V Wagner, T Warneke, T Wiacek, A Wood, S TI Comparisons between SCIAMACHY and ground-based FTIR data for total columns of CO, CH4, CO2 and N2O SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID TRUTHING-STATION-ZUGSPITZE; ATMOSPHERIC METHANE; ONBOARD ENVISAT; CARBON-MONOXIDE; WFM-DOAS; RETRIEVAL; PERFORMANCE; CALIBRATION; VALIDATION; INSTRUMENT AB Total column amounts of CO, CH4, CO2 and N2O retrieved from SCIAMACHY nadir observations in its near-infrared channels have been compared to data from a ground-based quasi-global network of Fourier-transform infrared ( FTIR) spectrometers. The SCIAMACHY data considered here have been produced by three different retrieval algorithms, WFM-DOAS (version 0.5 for CO and CH4 and version 0.4 for CO2 and N2O), IMAP- DOAS ( version 1.1 and 0.9 (for CO)) and IMLM (version 6.3) and cover the January to December 2003 time period. Comparisons have been made for individual data, as well as for monthly averages. To maximize the number of reliable coincidences that satisfy the temporal and spatial collocation criteria, the SCIAMACHY data have been compared with a temporal 3rd order polynomial interpolation of the ground-based data. Particular attention has been given to the question whether SCIAMACHY observes correctly the seasonal and latitudinal variability of the target species. The present results indicate that the individual SCIAMACHY data obtained with the actual versions of the algorithms have been significantly improved, but that the quality requirements, for estimating emissions on regional scales, are not yet met. Nevertheless, possible directions for further algorithm upgrades have been identified which should result in more reliable data products in a near future. C1 Belgian Inst Space Astron, Brussels, Belgium. Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany. Univ Karlsruhe, IMK ASF, Karlsruhe, Germany. Environm Canada, Downsview, ON, Canada. Univ Wollongong, Wollongong, NSW, Australia. Inst Astrophys & Geophys, Liege, Belgium. Chalmers Univ Technol Radio & Space Sci, Gothenburg, Sweden. Univ Heidelberg, Inst Environm Phys, Heidelberg, Germany. NIWA, Wellington, New Zealand. Forschungszentrum Karlsruhe, IMK IFU, Garmisch Partenkirchen, Germany. Univ Toronto, Dept Phys, Toronto, ON, Canada. Univ Bremen, Inst Environm Phys, FB1, D-2800 Bremen 33, Germany. SRON, Utrecht, Netherlands. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Dils, B (reprint author), Belgian Inst Space Astron, Brussels, Belgium. EM bart.dils@oma.be RI Buchwitz, Michael/G-1510-2011; Velazco, Voltaire/H-2280-2011; Strong, Kimberly/D-2563-2012; Blumenstock, Thomas/K-2263-2012; Sussmann, Ralf/K-3999-2012; Garmisch-Pa, Ifu/H-9902-2014; Jones, Nicholas/G-5575-2011; Frankenberg, Christian/A-2944-2013; Notholt, Justus/P-4520-2016; OI Velazco, Voltaire/0000-0002-1376-438X; Jones, Nicholas/0000-0002-0111-2368; Frankenberg, Christian/0000-0002-0546-5857; Notholt, Justus/0000-0002-3324-885X; Mahieu, Emmanuel/0000-0002-5251-0286 NR 32 TC 64 Z9 67 U1 0 U2 14 PU EUROPEAN GEOSCIENCES UNION PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 1680-7316 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JUN 8 PY 2006 VL 6 BP 1953 EP 1976 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 050YI UT WOS:000238126400001 ER PT J AU Hall, DK Williams, RS Casey, KA DiGirolamo, NE Wan, Z AF Hall, DK Williams, RS Casey, KA DiGirolamo, NE Wan, Z TI Satellite-derived, melt-season surface temperature of the Greenland Ice Sheet (2000-2005) and its relationship to mass balance SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CLEAR-SKY; IN-SITU; EXTENT AB Mean, clear-sky surface temperature of the Greenland Ice Sheet was measured for each melt season from 2000 to 2005 using Moderate-Resolution Imaging Spectroradiometer (MODIS)-derived land-surface temperature (LST) data-product maps. During the period of most-active melt, the mean, clear-sky surface temperature of the ice sheet was highest in 2002 ( - 8.29 +/- 5.29 degrees C) and 2005 ( - 8.29 +/- 5.43 degrees C), compared to a 6-year mean of - 9.04 +/- 5.59 degrees C, in agreement with recent work by other investigators showing unusually extensive melt in 2002 and 2005. Surface-temperature variability shows a correspondence with the dry-snow facies of the ice sheet; a reduction in area of the dry-snow facies would indicate a more-negative mass balance. Surface-temperature variability generally increased during the study period and is most pronounced in the 2005 melt season; this is consistent with surface instability caused by air-temperature fluctuations. C1 NASA, Goddard Space Flight Ctr, Cryospher Sci Branch, Greenbelt, MD 20771 USA. US Geol Survey, Woods Hole Sci Ctr, Woods Hole, MA 02543 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Univ Calif Santa Barbara, Inst Computat Earth Syst Sci, Santa Barbara, CA 93106 USA. RP Hall, DK (reprint author), NASA, Goddard Space Flight Ctr, Cryospher Sci Branch, Code 614-1, Greenbelt, MD 20771 USA. EM dorothy.k.hall@nasa.gov RI Hall, Dorothy/D-5562-2012; Casey, Kimberly/A-4478-2013 OI Casey, Kimberly/0000-0002-6115-7525 NR 23 TC 19 Z9 20 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 JUN 8 PY 2006 VL 33 IS 11 AR L11501 DI 10.1029/2006GL026444 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 052FR UT WOS:000238218400006 ER PT J AU Elachi, C Wall, S Janssen, M Stofan, E Lopes, R Kirk, R Lorenz, R Lunine, J Paganelli, F Soderblom, L Wood, C Wye, L Zebker, H Anderson, Y Ostro, S Allison, M Boehmer, R Callahan, P Encrenaz, P Flamini, E Francescetti, G Gim, Y Hamilton, G Hensley, S Johnson, W Kelleher, K Muhleman, D Picardi, G Posa, F Roth, L Seu, R Shaffer, S Stiles, B Vetrella, S West, R AF Elachi, C Wall, S Janssen, M Stofan, E Lopes, R Kirk, R Lorenz, R Lunine, J Paganelli, F Soderblom, L Wood, C Wye, L Zebker, H Anderson, Y Ostro, S Allison, M Boehmer, R Callahan, P Encrenaz, P Flamini, E Francescetti, G Gim, Y Hamilton, G Hensley, S Johnson, W Kelleher, K Muhleman, D Picardi, G Posa, F Roth, L Seu, R Shaffer, S Stiles, B Vetrella, S West, R TI Titan Radar Mapper observations from Cassini's T3 fly-by SO NATURE LA English DT Article ID SURFACE; WINDS AB Cassini's Titan Radar Mapper imaged the surface of Saturn's moon Titan on its February 2005 fly-by ( denoted T-3), collecting high-resolution synthetic-aperture radar and larger-scale radiometry and scatterometry data. These data provide the first definitive identification of impact craters on the surface of Titan, networks of fluvial channels and surficial dark streaks that may be longitudinal dunes. Here we describe this great diversity of landforms. We conclude that much of the surface thus far imaged by radar of the haze-shrouded Titan is very young, with persistent geologic activity. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Proxemy Res, Bowie, MD 20715 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. IFSI INAF, I-00133 Rome, Italy. Planetary Sci Inst, Tucson, AZ 85719 USA. Stanford Univ, Stanford, CA 94305 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Observ Paris, F-92195 Meudon, France. Alenia Aerosp, I-00131 Rome, Italy. Fac Ingn, I-80125 Naples, Italy. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Univ Roma La Sapienza, I-00184 Rome, Italy. Politecn Bari, INFM, I-70126 Bari, Italy. Politecn Bari, Dipartimento Interateneo Fis, I-70126 Bari, Italy. RP Wall, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM steve.wall@jpl.nasa.gov 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 17 TC 69 Z9 69 U1 0 U2 8 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUN 8 PY 2006 VL 441 IS 7094 BP 709 EP 713 DI 10.1038/nature04786 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 050NL UT WOS:000238095100044 PM 16760968 ER PT J AU Roberge, A Feldman, PD Weinberger, AJ Deleuil, M Bouret, JC AF Roberge, A Feldman, PD Weinberger, AJ Deleuil, M Bouret, JC TI Stabilization of the disk around beta Pictoris by extremely carbon-rich gas SO NATURE LA English DT Article ID CIRCUMSTELLAR DISK AB The edge-on disk surrounding the nearby young star beta Pictoris is the archetype of `debris disks', which are composed of dust and gas produced by collisions between - and evaporation of - planetesimals, analogues of Solar System comets and asteroids. These disks may provide insight into the formation and early evolution of terrestrial planets. Previous work on beta Pic concluded that the disk gas has roughly solar abundances of elements(1), but this poses a problem because such gas should rapidly be blown away from the star, contrary to observations showing a stable gas disk in keplerian rotation(1,2). Here we report the detection of singly and doubly ionized carbon ( C II, C III) and neutral atomic oxygen ( O I) gas in the beta Pic disk. Carbon is extremely overabundant relative to every other measured element. This appears to solve the problem of the stable gas disk, because the carbon overabundance should keep the gas disk in keplerian rotation(3). The overabundance may indicate that the gas is produced from material more carbon-rich than expected of Solar System analogues. C1 NASA, Goddard Space Flight Ctr, Exoplanets & Stellar Astrophys Lab, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. Lab Astrophys Marseille, F-13376 Marseille 12, France. RP Roberge, A (reprint author), NASA, Goddard Space Flight Ctr, Exoplanets & Stellar Astrophys Lab, Greenbelt, MD 20771 USA. EM akir@milkyway.gsfc.nasa.gov RI Roberge, Aki/D-2782-2012 OI Roberge, Aki/0000-0002-2989-3725 NR 18 TC 71 Z9 71 U1 0 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 JUN 8 PY 2006 VL 441 IS 7094 BP 724 EP 726 DI 10.1038/nature04832 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 050NL UT WOS:000238095100047 PM 16760971 ER PT J AU Kalashnikova, OV Kahn, R AF Kalashnikova, Olga V. Kahn, Ralph TI Ability of multiangle remote sensing observations to identify and distinguish mineral dust types: 2. Sensitivity over dark water SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID IMAGING SPECTRORADIOMETER MISR; OPTICAL-PROPERTIES; AEROSOL PROPERTIES; RETRIEVAL; SCATTERING; OCEAN; CLOUDS AB We explore the ability of multiangle, multispectral measurements, such as those from the Multiangle Imaging SpectroRadiometer (MISR), to retrieve mineral dust properties. We first investigate MISR sensitivity theoretically, to a selection of medium-mode particle shapes, to single-scattering albedo (SSA), and to the ratio of medium- to large-mode aerosol optical thickness (AOT). Favorable, but not ideal, viewing conditions over dark water are assumed, and new dust optical models are adopted. This study shows sensitivity to differences in the angular spectral signals of medium- mode shapes when column midvisible AOT is greater than similar to 0.15 for components contributing 15-20% or more to the AOT. MISR-like retrievals can also distinguish strongly absorbing (red channel SSA similar to 0.94) from less absorbing (SSA similar to 0.98-0.99) dust particles. Bimodal size sensitivity results suggest that MISR can distinguish the ratio of medium to larger components in roughly 20% midvisible AOT increments. For five Saharan dust field events over homogeneous, cloud-free dark water near the Cape Verde AERONET station, MISR research retrieval results were dominated by weakly absorbing medium grains. MISR-retrieved spectral AOT was within 0.02 of the Aerosol Robotic Network (AERONET), except for one spatially heterogeneous AOT>1 case, and one where AERONET retrieved a significant component <0.1 mu m in radius. In two cases where AERONET ran retrievals assuming nonspherical (spheroidal) particles, SSA fell within 0.02 of MISR. When included in the MISR Standard Aerosol Retrieval Algorithm, the new dust optical models improve both the coverage of successful retrievals and the spectral AOT agreement with near-coincident AERONET measurements. Large-mode dust models and available field constraint limitations are being addressed in continuing work. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kalashnikova, OV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM olga.v.kalashnikova@jpl.nasa.gov RI Kahn, Ralph/D-5371-2012 OI Kahn, Ralph/0000-0002-5234-6359 NR 23 TC 43 Z9 45 U1 0 U2 2 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 JUN 7 PY 2006 VL 111 IS D11 AR D11207 DI 10.1029/2005JD006756 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 052FY UT WOS:000238219200010 ER PT J AU Mace, GG Benson, S Sonntag, KL Kato, S Min, QL Minnis, P Twohy, CH Poellot, M Dong, XQ Long, C Zhang, QQ Doelling, DR AF Mace, Gerald G. Benson, Sally Sonntag, Karen L. Kato, Seiji Min, Qilong Minnis, Patrick Twohy, Cynthia H. Poellot, Michael Dong, Xiquan Long, Charles Zhang, Qiuqing Doelling, David R. TI Cloud radiative forcing at the atmospheric radiation measurement program climate research facility: 1. Technique, validation, and comparison to satellite-derived diagnostic quantities SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PARTICLE TERMINAL VELOCITIES; ICE WATER-CONTENT; ARM SGP SITE; MICROWAVE RADIOMETER; CIRRUS CLOUDS; STRATUS CLOUD; ACCURATE PARAMETERIZATION; MICROPHYSICAL PROPERTIES; DOPPLER RADAR; OPTICAL DEPTH AB It has been hypothesized that continuous ground-based remote sensing measurements from collocated active and passive remote sensors combined with regular soundings of the atmospheric thermodynamic structure can be combined to describe the effects of clouds on the clear sky radiation fluxes. We critically test that hypothesis in this paper and a companion paper (part 2). Using data collected at the Southern Great Plains (SGP) Atmospheric Radiation Measurement (ARM) site sponsored by the U. S. Department of Energy, we explore an analysis methodology that results in the characterization of the physical state of the atmospheric profile at time resolutions of 5 min and vertical resolutions of 90 m. The description includes thermodynamics and water vapor profile information derived by merging radiosonde soundings with ground-based data and continues through specification of the cloud layer occurrence and microphysical and radiative properties derived from retrieval algorithms and parameterizations. The description of the atmospheric physical state includes a calculation of the clear and cloudy sky solar and infrared flux profiles. Validation of the methodology is provided by comparing the calculated fluxes with top of atmosphere (TOA) and surface flux measurements and by comparing the total column optical depths to independently derived estimates. We find over a 1-year period of comparison in overcast uniform skies that the calculations are strongly correlated to measurements with biases in the flux quantities at the surface and TOA of less than 6% and median fractional errors ranging from 12% to as low as 2%. In the optical depth comparison for uniform overcast skies during the year 2000 where the optical depth varies over more than 3 orders of magnitude we find a mean positive bias of less than 1% and a 0.6 correlation coefficient. In addition to a case study where we examine the cloud radiative effects at the TOA, surface and atmosphere by a middle latitude cyclone, we examine the cloud top pressure and optical depth retrievals of ISCCP and LBTM over a period of 1 year. Using overcast periods from the year 2000, we find that the satellite algorithms tend to compare well with data overall but there is a tendency to bias cloud tops into the middle troposphere and underestimate optical depth in high optical depth events. C1 Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. SUNY Albany, Atmospher Sci Res Ctr, Albany, NY 12203 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA. Univ N Dakota, Dept Atmospher Sci, Grand Forks, ND 58202 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. Analyt Serv & Mat Inc, Hampton, VA 23666 USA. RP Mace, GG (reprint author), Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. EM mace@met.utah.edu RI Minnis, Patrick/G-1902-2010; OI Minnis, Patrick/0000-0002-4733-6148; Dong, Xiquan/0000-0002-3359-6117 NR 65 TC 47 Z9 47 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 JUN 7 PY 2006 VL 111 IS D11 AR D11S90 DI 10.1029/2005JD005921 PG 28 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 052FY UT WOS:000238219200001 ER PT J AU Saitoh, N Hayashida, S Sugita, T Nakajima, H Yokota, T Hayashi, M Shiraishi, K Kanzawa, H Ejiri, MK Irie, H Tanaka, T Terao, Y Bevilacqua, RM Randall, CE Thomason, LW Taha, G Kobayashi, H Sasano, Y AF Saitoh, N. Hayashida, S. Sugita, T. Nakajima, H. Yokota, T. Hayashi, M. Shiraishi, K. Kanzawa, H. Ejiri, M. K. Irie, H. Tanaka, T. Terao, Y. Bevilacqua, R. M. Randall, C. E. Thomason, L. W. Taha, G. Kobayashi, H. Sasano, Y. TI Intercomparison of ILAS-II version 1.4 aerosol extinction coefficient at 780 nm with SAGE II, SAGE III, and POAM III SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID POLAR STRATOSPHERIC CLOUDS; LIMB ATMOSPHERIC SPECTROMETER; RETRIEVAL ALGORITHM; SIZE DISTRIBUTION; OZONE; VALIDATION; CLIMATOLOGY; SATELLITE; WINTER; INSTRUMENT AB The Improved Limb Atmospheric Spectrometer (ILAS)-II on board the Advanced Earth Observing Satellite (ADEOS)-II observed stratospheric aerosol in visible/near-infrared/infrared spectra over high latitudes in the Northern and Southern hemispheres, intermittently from January to March and continuously from April through October 2003. This study assesses the data quality of ILAS-II version 1.4 (V1.4) aerosol extinction coefficient at 780 nm. In the Northern Hemisphere (NH), aerosol extinction coefficient (AEC) from ILAS-II agreed with extinctions from SAGE II and SAGE III within +/- 10% and with extinction from POAM III within +/- 15% at heights below 20 km. From 20 to 26 km, ILAS-II AEC was smaller than extinctions from the other three sensors; differences between ILAS-II and SAGE II ranged from 10% at 20 km to 34% at 26 km in the NH. Over the Southern Hemisphere (SH), ILAS-II AEC from 20 to 25 km in February was 12-66% below SAGE II extinction. The difference increased with increasing altitude. Comparisons between ILAS-II and POAM III from January to May in the SH ("non-PSC season'') yielded qualitatively similar results. From June to October ("PSC season''), ILAS-II extinction was also smaller than POAM III extinction above 17 km; however, ILAS-II extinction agreed with POAM III extinction to within +/- 15% from 12 to 17 km during the PSC season. The comparisons indicate that in both hemispheres the ILAS-II V1.4 AEC is comparable to extinctions from other measurements below approximately 20 km and systematically low above approximately 20 km although the mean difference is as small as similar to 2x10(-5) km(-1) during the non-PSC season. C1 Natl Inst Environm Studies, Tsukuba, Ibaraki 3050053, Japan. Nara Womens Univ, Fac Sci, Nara 6308506, Japan. Fukuoka Univ, Fac Sci, Fukuoka 8140180, Japan. Nagoya Univ, Grad Sch Environm Studies, Dept Earth & Environm Sci, Nagoya, Aichi 4648601, Japan. Utah State Univ, Ctr Atmospher & Space Sci, Logan, UT 84322 USA. Japan Agcy Marine Earth Sci & Technol, Frontier Res Ctr Global Change, Yokohama, Kanagawa 2360001, Japan. Harvard Univ, Div Engn & Appl Sci & Technol, Cambridge, MA 02138 USA. USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80303 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Cent Res Inst Elect Power Ind, Komae, Tokyo 2018511, Japan. RP Saitoh, N (reprint author), Univ Tokyo, Ctr Climate Syst Res, Gen Res Bldg,5-1-5 Kashiwanoha, Kashiwa, Chiba 2778568, Japan. EM snaoko@ccsr.u-tokyo.ac.jp RI Sasano, Yasuhiro/C-2927-2009; Terao, Yukio/A-2099-2008; Randall, Cora/L-8760-2014; OI Sasano, Yasuhiro/0000-0001-7470-5642; Terao, Yukio/0000-0003-2345-7073; Randall, Cora/0000-0002-4313-4397; Sugita, Takafumi/0000-0002-0508-7040 NR 40 TC 7 Z9 8 U1 0 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 JUN 7 PY 2006 VL 111 IS D11 AR D11S05 DI 10.1029/2005JD006315 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 052FY UT WOS:000238219200003 ER PT J AU Ryan, JP Ueki, I Chao, Y Zhang, HC Polito, PS Chavez, FP AF Ryan, John P. Ueki, Iwao Chao, Yi Zhang, Hongchun Polito, Paulo S. Chavez, Francisco P. TI Western Pacific modulation of large phytoplankton blooms in the central and eastern equatorial Pacific SO JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES LA English DT Article ID PAPUA-NEW-GUINEA; 1997-1998 EL-NINO; PRIMARY PRODUCTIVITY; IRON DISTRIBUTIONS; SEPIK RIVER; OCEAN; TOPEX/POSEIDON; UNDERCURRENT; CIRCULATION; SEDIMENT AB [1] Satellite observations show that large-scale phytoplankton blooms (increases in chlorophyll) occurred in the equatorial Pacific in 1998, 2003, and 2005, following termination of the three most recent El Nino events. The occurrence of blooms following successive El Nino events cannot be explained by local enhancement of vertical nutrient flux, as evidenced by observations of equatorial winds, thermocline depth, and the depth and strength of the Equatorial Undercurrent (EUC, which supplies the limiting nutrient iron to the euphotic zone). However, near the peak of each El Nino event (late in 1997, 2002, and 2004), while the thermocline of the western equatorial Pacific was anomalously shallow, the flow of the New Guinea Coastal Undercurrent (NGCUC, which is the primary source of iron-enriched waters to the EUC) intensified, and its core shoaled from > 200 m to similar to 100 m depth. Analysis of NGCUC variability using a high-resolution, terrain-following three-dimensional ocean circulation model simulation indicates that as the NGCUC shoals and intensifies, it develops meanders and eddies that augment coupling of the New Guinea shelf and upper slope to the EUC. We hypothesize that these changes in NGCUC circulation during El Nino enhance iron transport from the New Guinea margin into the EUC and thereby trigger large-scale blooms when iron-enriched waters subsequently reach the euphotic zone along the equator. The threefold to fourfold chlorophyll increases over large regions, up to similar to 5 x 105 km(2), must have profound impacts on the equatorial ecosystem and biogeochemical cycles. C1 Monterey Bay Aquarium Res Inst, Moss Landing, CA USA. Japan Agcy Marine Earth Sci & Technol, Yokosuka, Kanagawa, Japan. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Raytheon Informat Technol & Sci Serv, Pasadena, CA USA. Univ Sao Paulo, Inst Oceanog, BR-05508 Sao Paulo, Brazil. RP Ryan, JP (reprint author), Monterey Bay Aquarium Res Inst, Moss Landing, CA USA. EM ryjo@mbari.org RI Polito, Paulo/F-3040-2013 OI Polito, Paulo/0000-0003-2217-3853 NR 45 TC 37 Z9 38 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-BIOGEO JI J. Geophys. Res.-Biogeosci. PD JUN 7 PY 2006 VL 111 IS G2 AR G02013 DI 10.1029/2005JG000084 PG 14 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA 090XY UT WOS:000240990800002 ER PT J AU Sobral, JHA Abdu, MA Gonzalez, WD Gonzalez, AC Tsurutani, BT Da Silva, RRL Barbosa, IG Arruda, DCS Denardini, CM Zamlutti, CJ Guarnieri, F AF Sobral, Jose Humberto A. Abdu, Mangalathayil A. Gonzalez, Walter D. Gonzalez, Alicia C. Tsurutani, Bruce T. Da Silva, Renato R. L. Barbosa, Isabela G. Arruda, Daniela C. S. Denardini, Clezio M. Zamlutti, Carlos J. Guarnieri, Fernando TI Equatorial ionospheric responses to high-intensity long-duration auroral electrojet activity (HILDCAA) SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID LOW-LATITUDE IONOSPHERE; DISTURBANCE DYNAMO; MAGNETIC STORM; F-REGION; MAGNETOSPHERIC DISTURBANCES; DRIFT VELOCITIES; AMERICAN SECTOR; FIELD; SYSTEM; THERMOSPHERE AB [1] The knowledge of the coupling processes between the magnetosphere and the equatorial ionosphere is of basic importance to the understanding of the near-Earth space weather. This study focuses on observational results of such coupling processes based on data collected during the phenomenon defined as high-intensity long-duration continuous AE activity (HILDCAA) which occurs outside the main phase of geomagnetic storms. The fact that the responses of the equatorial/low-latitude ionosphere to HILDCAA events have not been specifically focused so far is one of the motivations for this study. Ionosonde data on hmF2, h'F, and foF2 from three locations in Brazil (magnetic equatorial station Sao Luis (SL), subequatorial station Fortaleza (FZ), and low-latitude station Cachoeira Paulista (CP)) are analyzed together with ACE satellite data on solar wind and interplanetary magnetic and electric fields during three HILDCAA events that occurred in the years 2000 and 2001. The results did not indicate any presence of penetrating electric field disturbance during these events. However, they provided clear evidence of disturbance dynamo electric field and disturbance thermospheric winds, through F layer height changes that were similar but generally less intense than those observed during a typical storm event. The foF2 presented no particular disturbances that can be clearly attributed to the HILDCAA event. Previous extensive studies carried out by the authors on ionospheric storm effects for these same three stations clearly illustrate the much more intense F layer storm disturbances compared with HILDCAA events disturbances. C1 Inst Nacl Pesquisas Espaciais, Sao Paulo, Brazil. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sobral, JHA (reprint author), Inst Nacl Pesquisas Espaciais, Sao Jose dos Campos,Caixa Postal 515, Sao Paulo, Brazil. EM jsobral@dae.impe.br RI De Nardin, Clezio/C-4103-2012 OI De Nardin, Clezio/0000-0002-3624-2461 NR 52 TC 8 Z9 9 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-SPACE JI J. Geophys. Res-Space Phys. PD JUN 6 PY 2006 VL 111 IS A7 AR A07S02 DI 10.1029/2005JA011393 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 052GV UT WOS:000238221800001 ER PT J AU Kleinbohl, A Toon, GC Sen, B Blavier, JFL Weisenstein, DK Strekowski, RS Nicovich, JM Wine, PH Wennberg, PO AF Kleinbohl, A Toon, GC Sen, B Blavier, JFL Weisenstein, DK Strekowski, RS Nicovich, JM Wine, PH Wennberg, PO TI On the stratospheric chemistry of hydrogen cyanide SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATMOSPHERIC CHEMISTRY; HCN; CH3CN; TROPOSPHERE; BUDGETS; SINKS AB HCN profiles measured by solar occultation spectrometry during 10 balloon flights of the JPL MkIV instrument are presented. The HCN profiles reveal a compact correlation with stratospheric tracers. Calculations with a 2D-model using established rate coefficients for the reactions of HCN with OH and O(D-1) severely underestimate the measured HCN in the middle and upper stratosphere. The use of newly available rate coefficients for these reactions gives reasonable agreement of measured and modeled HCN. An HCN yield of similar to 30% from the reaction of CH3CN with OH is consistent with the measurements. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Atmospher & Environm Res Inc, Lexington, MA 02421 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. CALTECH, Pasadena, CA 91125 USA. RP Kleinbohl, A (reprint author), CALTECH, Jet Prop Lab, Mail Stop 183-501,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM armin.kleinboehl@jpl.nasa.gov RI Strekowski, Rafal/D-2271-2010; Wennberg, Paul/A-5460-2012; Strekowski, Rafal/D-2732-2013; Wine, Paul/J-4820-2015 OI Strekowski, Rafal/0000-0003-0030-9318; Strekowski, Rafal/0000-0003-0030-9318; Wine, Paul/0000-0002-5537-4304 NR 28 TC 14 Z9 14 U1 0 U2 8 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 JUN 3 PY 2006 VL 33 IS 11 AR L11806 DI 10.1029/2006GL026015 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 050EF UT WOS:000238069600004 ER PT J AU Kwok, R Cunningham, GF Zwally, HJ Yi, D AF Kwok, R. Cunningham, G. F. Zwally, H. J. Yi, D. TI ICESat over Arctic sea ice: Interpretation of altimetric and reflectivity profiles SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID OCEAN; SAR; PROJECT; MODEL AB We provide an assessment of the ICESat altimeter for studying the Arctic Ocean and examine the magnitude of the large- and small-scale expressions of geophysical processes embedded in the elevation profiles. This analysis includes data from six surveys. At the large scale the response of the ice-covered ocean to atmospheric loading is near ideal (i.e., approximately -1 cm/hPa). After removal of the inverted barometer effects and best available geoid the elevation signal is still dominated by unresolved geoid residuals (similar to 0.4 m) that can be seen in the similarity of the remaining spatial patterns. Seasonal differences in elevations over multiyear ice are consistent with snow depth climatology; the broad differential spatial patterns are indicative of interannual differences in multiyear ice coverage associated with advection. Patterns in the derived surface roughness fields correspond to the seasonal and perennial ice zones seen in QuikSCAT data. At the small scale, near-coincident RADARSAT imagery provides a spatial context for understanding the signature of the observed elevations, waveforms, and reflectivity, in particular, those associated with thin ice, open water, multiyear ice, and ridges. The precision of the elevation estimates measured over relatively flat sea ice, identified in synthetic aperture radar (SAR) imagery, is similar to 2 cm. The unambiguous identification of ridged areas in coupled ICESat/RADARSAT analysis could be used to enhance the utility of SAR imagery for examining ridge distributions. Over a 20 day period we monitored the evolution of the reflectivity of a newly opened lead. The steep increase in reflectivity due to snow coverage suggests that dips in ICESat reflectivity are likely areas of thin ice and could serve as a basis for selection of tie points for use as sea level reference. Identification of these tie points is crucial for accurate estimation of sea ice freeboard. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Cryospher Sci Branch, Greenbelt, MD 20771 USA. SGT Inc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kwok, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM ron.kwok@jpl.nasa.gov RI Kwok, Ron/A-9762-2008 OI Kwok, Ron/0000-0003-4051-5896 NR 29 TC 44 Z9 46 U1 1 U2 8 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 JUN 3 PY 2006 VL 111 IS C6 AR C06006 DI 10.1029/2005JC003175 PG 20 WC Oceanography SC Oceanography GA 050FH UT WOS:000238072400001 ER PT J AU Lumpe, J Bevilacqua, R Randall, C Nedoluha, G Hoppel, K Russell, J Harvey, VL Schiller, C Sen, B Taha, G Toon, G Vomel, H AF Lumpe, J. Bevilacqua, R. Randall, C. Nedoluha, G. Hoppel, K. Russell, J. Harvey, V. L. Schiller, C. Sen, B. Taha, G. Toon, G. Voemel, H. TI Validation of Polar Ozone and Aerosol Measurement (POAM) III version 4 stratospheric water vapor SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID HALOGEN OCCULTATION EXPERIMENT; POAM-III MEASUREMENTS; LOWERMOST STRATOSPHERE; UPPER TROPOSPHERE; SAGE-II; ART.; DEHYDRATION; HYGROMETER; AIRCRAFT; VORTEX AB The Polar Ozone and Aerosol Measurement (POAM) III solar occultation instrument has been measuring water vapor at high latitudes since April 1998. Retrievals extend from 5 to 50 km, with 5-7% precision throughout the stratosphere and a vertical resolution of 1 (3) km in the lower (upper) stratosphere. Estimated systematic errors in the stratosphere are 10-15%. In this paper, we validate the POAM III version 4 stratospheric water vapor using correlative measurements from satellite, airborne, and balloon-borne platforms. The resulting comparisons show that POAM water vapor is high compared to correlative measurements in the middle to lower stratosphere. The satellite (Halogen Occultation Experiment (HALOE) and Stratospheric Aerosol and Gas Experiment (SAGE) II) comparisons also indicate a sunrise/sunset bias in the POAM data, with sunset (Southern Hemisphere) retrievals larger than sunrise (Northern Hemisphere) retrievals by 5-10%. In the Northern Hemisphere, POAM is approximately 5-10% high compared to all validation data sets between 12 and 35 km. At higher altitudes this difference decreases, such that POAM agrees with HALOE at 40 km and is lower by 10% at 50 km. In the Southern Hemisphere, POAM is 15-25% higher than HALOE below 35 km, with differences decreasing to 10% by 50 km. Similar differences are seen with SAGE II. Despite these systematic differences the POAM water vapor data are self-consistent and show no long-term trends in accuracy or precision. Statistical comparisons of the water vapor variability measured by POAM, HALOE, and SAGE II show very good agreement. The POAM data are therefore valid for scientific studies, and the science community is encouraged to use this unique data set. C1 Computat Phys Inc, Boulder, CO 80301 USA. USN, Res Lab, Washington, DC 20375 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80303 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. Forschungszentrum Julich, Inst Chem & Dynam Geosphare 1, D-52425 Julich, Germany. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Lumpe, J (reprint author), Computat Phys Inc, 1650 38th St,Suite 105W, Boulder, CO 80301 USA. EM lumpe@cpi.com RI Schiller, Cornelius/B-1004-2013; Randall, Cora/L-8760-2014 OI Randall, Cora/0000-0002-4313-4397 NR 31 TC 19 Z9 19 U1 1 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 JUN 2 PY 2006 VL 111 IS D11 AR D11301 DI 10.1029/2005JD006763 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 050ES UT WOS:000238070900007 ER PT J AU Nakajima, H Sugita, T Irie, H Saitoh, N Kanzawa, H Oelhaf, H Wetzel, G Toon, GC Sen, B Blavier, JF Traub, WA Jucks, K Johnson, DG Yokota, T Sasano, Y AF Nakajima, H. Sugita, T. Irie, H. Saitoh, N. Kanzawa, H. Oelhaf, H. Wetzel, G. Toon, G. C. Sen, B. Blavier, J. -F. Traub, W. A. Jucks, K. Johnson, D. G. Yokota, T. Sasano, Y. TI Measurements of ClONO2 by the Improved Limb Atmospheric Spectrometer (ILAS) in high-latitude stratosphere: New products using version 6.1 data processing algorithm SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NITRIC-ACID TRIHYDRATE; ARCTIC VORTEX; SPECTROSCOPIC DATABASE; RETRIEVAL ALGORITHM; OPTICAL-CONSTANTS; CHLORINE NITRATE; OZONE DEPLETION; POLAR VORTEX; VALIDATION; PROFILES AB We report the first continuous measurements of chlorine nitrate (ClONO2) in high-latitude regions taken by the Improved Limb Atmospheric Spectrometer (ILAS) on board the Advanced Earth Observing Satellite (ADEOS) and processed using the latest data retrieval algorithm (version 6.1). Performance of the measurements, validation with three balloon-borne sensors, and seasonal variation of ClONO2 in the Arctic and Antarctic stratosphere are presented, as well as a brief description of the version 6.1 algorithm and data characteristics for both the Arctic and Antarctic. Although the ILAS-measured ClONO2 data show, on average, similar to 30% lower values than the validation data, they agree with validation data within the combined total error (similar to 20-40%) of the ClONO2 measurements at similar to 15- to 32-km altitudes. In the Arctic, enhancement of ClONO2 amounts was observed in spring 1997 after the appearance of polar stratospheric clouds (PSCs) inside the polar vortex. This is the result of preference for ClONO2 formation rather than HCl after the activation of ClOx in this Arctic spring of 1997. In the Antarctic, ClONO2 amounts showed strong local time/latitudinal dependence around the austral fall equinox in 1997. C1 Natl Inst Environm Studies, Tsukuba, Ibaraki 3058506, Japan. Japan Agcy Marine Earth Sci & Technol, Frontier Res Ctr Global Change, Yokohama, Kanagawa 2360001, Japan. Nagoya Univ, Grad Sch Environm Studies, Nagoya, Aichi 4648601, Japan. Forschungszentrum Karlsruhe, Inst Meteorol & Klimaforsch, D-76021 Karlsruhe, Germany. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Nakajima, H (reprint author), Natl Inst Environm Studies, Tsukuba, Ibaraki 3058506, Japan. EM hide@nies.go.jp RI Sasano, Yasuhiro/C-2927-2009; Wetzel, Gerald/A-7065-2013; Oelhaf, Hermann/A-7895-2013; Johnson, David/F-2376-2015; OI Sasano, Yasuhiro/0000-0001-7470-5642; Johnson, David/0000-0003-4399-5653; Sugita, Takafumi/0000-0002-0508-7040 NR 51 TC 12 Z9 12 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 2 PY 2006 VL 111 IS D11 AR D11S09 DI 10.1029/2005JD006441 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 050ES UT WOS:000238070900003 ER PT J AU Fujiwara, A Kawaguchi, J Yeomans, DK Abe, M Mukai, T Okada, T Saito, J Yano, H Yoshikawa, M Scheeres, DJ Barnouin-Jha, O Cheng, AF Demura, H Gaskell, RW Hirata, N Ikeda, H Kominato, T Miyamoto, H Nakamura, AM Nakamura, R Sasaki, S Uesugi, K AF Fujiwara, A Kawaguchi, J Yeomans, DK Abe, M Mukai, T Okada, T Saito, J Yano, H Yoshikawa, M Scheeres, DJ Barnouin-Jha, O Cheng, AF Demura, H Gaskell, RW Hirata, N Ikeda, H Kominato, T Miyamoto, H Nakamura, AM Nakamura, R Sasaki, S Uesugi, K TI The rubble-pile asteroid Itokawa as observed by Hayabusa SO SCIENCE LA English DT Article ID 25143 1998 SF36; DISRUPTION; 433-EROS; CRATERS; MISSION AB During the interval from September through early December 2005, the Hayabusa spacecraft was in close proximity to near-Earth asteroid 25143 Itokawa, and a variety of data were taken on its shape, mass, and surface topography as well as its mineralogic and elemental abundances. The asteroid's orthogonal axes are 535, 294, and 209 meters, the mass is 3.51 x 10(10) kilograms, and the estimated bulk density is 1.9 +/- 0.13 grams per cubic centimeter. The correspondence between the smooth areas on the surface ( Muses Sea and Sagamihara) and the gravitationally low regions suggests mass movement and an effective resurfacing process by impact jolting. Itokawa is considered to be a rubble-pile body because of its low bulk density, high porosity, boulder-rich appearance, and shape. The existence of very large boulders and pillars suggests an early collisional breakup of a preexisting parent asteroid followed by a re-agglomeration into a rubble-pile object. C1 JAXA, ISAS, Kanagawa 2298510, Japan. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Kobe Univ, Grad Sch Sci & Technol, Kobe, Hyogo 6578501, Japan. Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Aizu Univ, Sch Comp Sci & Engn, Fukushima 9658580, Japan. NEC Aerosp Syst Ltd, Kanagawa 2240053, Japan. Univ Tokyo, Dept Geosyst Engn, Tokyo 1138656, Japan. Natl Inst Adv Ind Sci & Technol, GTRC, Tsukuba, Ibaraki 3058568, Japan. Natl Astron Observ Japan, Mizusawa Astrodynam Observ, Mizusawa, Iwate 0230861, Japan. RP Fujiwara, A (reprint author), JAXA, ISAS, 3-1-1 Yoshinodai, Kanagawa 2298510, Japan. EM fujiwara@planeta.sci.isas.jaxa.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 30 TC 304 Z9 309 U1 1 U2 34 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 JUN 2 PY 2006 VL 312 IS 5778 BP 1330 EP 1334 DI 10.1126/science.1125841 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 048QM UT WOS:000237961600040 PM 16741107 ER PT J AU Abe, M Takagi, Y Kitazato, K Abe, S Hiroi, T Vilas, F Clark, BE Abell, PA Lederer, SM Jarvis, KS Nimura, T Ueda, Y Fujiwara, A AF Abe, M Takagi, Y Kitazato, K Abe, S Hiroi, T Vilas, F Clark, BE Abell, PA Lederer, SM Jarvis, KS Nimura, T Ueda, Y Fujiwara, A TI Near-infrared spectral results of asteroid Itokawa from the Hayabusa spacecraft SO SCIENCE LA English DT Article ID C MISSION TARGET; REFLECTANCE SPECTROSCOPY; 1998 SF36; EROS; ALBEDO AB The near-infrared spectrometer on board the Japanese Hayabusa spacecraft found a variation of more than 10% in albedo and absorption band depth in the surface reflectance of asteroid 25143 Itokawa. Spectral shape over the 1-micrometer absorption band indicates that the surface of this body has an olivine-rich mineral assemblage potentially similar to that of LL5 or LL6 chondrites. Diversity in the physical condition of Itokawa's surface appears to be larger than for other S-type asteroids previously explored by spacecraft, such as 433 Eros. C1 Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. Toho Gakuen Univ, Aichi 4658515, Japan. Univ Tokyo, Bunkyo Ku, Tokyo 1130033, Japan. Kobe Univ, Grad Sch Sci & Technol, Nada Ku, Kobe, Hyogo 6578501, Japan. Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. Univ Arizona, Multiple Mirror Telescope Observ, Tucson, AZ 85721 USA. Ithaca Coll, Dept Phys, Ithaca, NY 14850 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Calif State Univ San Bernardino, Dept Phys, San Bernardino, CA 92407 USA. ESC Grp Hamilton Sundstrand, Houston, TX 77058 USA. RP Abe, M (reprint author), Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, 3-1-1 Yoshinodai, Kanagawa 2298510, Japan. NR 27 TC 76 Z9 78 U1 0 U2 5 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 JUN 2 PY 2006 VL 312 IS 5778 BP 1334 EP 1338 DI 10.1126/science.1125718 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 048QM UT WOS:000237961600041 PM 16741108 ER PT J AU Saito, J Miyamoto, H Nakamura, R Ishiguro, M Michikami, T Nakamura, AM Demura, H Sasaki, S Hirata, N Honda, C Yamamoto, A Yokota, Y Fuse, T Yoshida, F Tholen, DJ Gaskell, RW Hashimoto, T Kubota, T Higuchi, Y Nakamura, T Smith, P Hiraoka, K Honda, T Kobayashi, S Furuya, M Matsumoto, N Nemoto, E Yukishita, A Kitazato, K Dermawan, B Sogame, A Terazono, J Shinohara, C Akiyama, H AF Saito, J Miyamoto, H Nakamura, R Ishiguro, M Michikami, T Nakamura, AM Demura, H Sasaki, S Hirata, N Honda, C Yamamoto, A Yokota, Y Fuse, T Yoshida, F Tholen, DJ Gaskell, RW Hashimoto, T Kubota, T Higuchi, Y Nakamura, T Smith, P Hiraoka, K Honda, T Kobayashi, S Furuya, M Matsumoto, N Nemoto, E Yukishita, A Kitazato, K Dermawan, B Sogame, A Terazono, J Shinohara, C Akiyama, H TI Detailed images of asteroid 25143 Itokawa from Hayabusa SO SCIENCE LA English DT Article ID GALILEO PHOTOMETRY; COLOR VARIATIONS; EJECTA BLOCKS; MUSES-C; EROS; REFLECTANCE; SIMULATION; REGOLITH; CAMERA; LUNAR AB Rendezvous of the Japanese spacecraft Hayabusa with the near-Earth asteroid 25143 Itokawa took place during the interval September through November 2005. The onboard camera imaged the solid surface of this tiny asteroid ( 535 meters by 294 meters by 209 meters) with a spatial resolution of 70 centimeters per pixel, revealing diverse surface morphologies. Unlike previously explored asteroids, the surface of Itokawa reveals both rough and smooth terrains. Craters generally show unclear morphologies. Numerous boulders on Itokawa's surface suggest a rubble-pile structure. C1 Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Hayabusa Project Team, Kanagawa 2298510, Japan. Tokai Univ, Sch Engn, Kanagawa 2591292, Japan. Univ Tokyo, Dept Geosyst Engn, Tokyo 1138656, Japan. Planetary Sci Inst, Tucson, AZ 85719 USA. Natl Inst Adv Ind Sci & Technol, Tsukuba, Ibaraki 3058568, Japan. JAXA, ISAS, Dept Planetary Sci, Kanagawa 2298510, Japan. Fukushima Natl Coll Technol, Iwaki, Fukushima 9708034, Japan. Kobe Univ, Grad Sch Sci & Technol, Kobe, Hyogo 6578501, Japan. Univ Aizu, Sch Engn & Comp Sci, Fukushima 9658580, Japan. Natl Astron Observ Japan, Mizusawa Astrogeodynam Observ, Oshu, Iwate 0230861, Japan. Remote Sensing Technol Ctr Japan, Tokyo 1060032, Japan. NAOJ, Subaru Telescope, Hilo, HI 96720 USA. NAOJ, Opt & Infrared Astron Div, Tokyo 1818588, Japan. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. JAXA, ISAS, Dept Spacecraft Engn, Kanagawa 2298510, Japan. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85705 USA. Bandung Inst Technol, Dept Astron, Bandung 40132, Indonesia. Bandung Inst Technol, Bosscha Observ, Bandung 40132, Indonesia. JAXA, Publ Affairs Dept, Tokyo 1008260, Japan. Akita Univ, Fac Engn & Resource Sci, Akita 0108502, Japan. RP Saito, J (reprint author), Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Hayabusa Project Team, 3-1-1 Yoshinodai, Kanagawa 2298510, Japan. EM saitoj@planeta.sci.isas.jaxa.jp RI Miyamoto, Hideaki/B-9666-2008; Miyamoto, Hideaki/E-3381-2012; Yoshida, Fumi/I-6389-2016; Nakamura, Akiko/I-1993-2012 OI Yoshida, Fumi/0000-0002-3286-911X; Nakamura, Akiko/0000-0001-6990-8496 NR 23 TC 109 Z9 109 U1 0 U2 16 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 JUN 2 PY 2006 VL 312 IS 5778 BP 1341 EP 1344 DI 10.1126/science.1125722 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 048QM UT WOS:000237961600043 PM 16741110 ER PT J AU Abe, S Mukai, T Hirata, N Barnouin-Jha, OS Cheng, AF Demura, H Gaskell, RW Hashimoto, T Hiraoka, K Honda, T Kubota, T Matsuoka, M Mizuno, T Nakamura, R Scheeres, DJ Yoshikawa, M AF Abe, S Mukai, T Hirata, N Barnouin-Jha, OS Cheng, AF Demura, H Gaskell, RW Hashimoto, T Hiraoka, K Honda, T Kubota, T Matsuoka, M Mizuno, T Nakamura, R Scheeres, DJ Yoshikawa, M TI Mass and local topography measurements of Itokawa by Hayabusa SO SCIENCE LA English DT Article ID LASER ALTIMETRY; NEAR-SHOEMAKER; MUSES-C; 433-EROS; MISSION; SURFACE; TARGET; SHAPE; LIDAR AB The ranging instrument aboard the Hayabusa spacecraft measured the surface topography of asteroid 25143 Itokawa and its mass. A typical rough area is similar in roughness to debris located on the interior wall of a large crater on asteroid 433 Eros, which suggests a surface structure on Itokawa similar to crater ejecta on Eros. The mass of Itokawa was estimated as (3.58 +/- 0.18) x 1010 kilograms, implying a bulk density of (1.95 +/- 0.14) grams per cubic centimeter for a volume of ( 1.84 +/- 0.09) x 10(7) cubic meters and a bulk porosity of similar to 40%, which is similar to that of angular sands, when assuming an LL ( low iron chondritic) meteorite composition. Combined with surface observations, these data indicate that Itokawa is the first subkilometer-sized small asteroid showing a rubble-pile body rather than a solid monolithic asteroid. C1 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, Fukushima 9658580, Japan. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. JAXA, ISAS, Kanagawa 2298510, Japan. NEC Aerosp Syst Co Ltd, Tokyo 1818551, Japan. Natl Inst Adv Ind Sci & Technol, Tsukuba, Ibaraki 3058568, Japan. Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. RP Abe, S (reprint author), Kobe Univ, Grad Sch Sci & Technol, Nada Ku, Kobe, Hyogo 6578501, Japan. EM avell@kobe-u.ac.jp RI Barnouin, Olivier/I-7475-2015 OI Barnouin, Olivier/0000-0002-3578-7750 NR 18 TC 105 Z9 105 U1 1 U2 11 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 JUN 2 PY 2006 VL 312 IS 5778 BP 1344 EP 1347 DI 10.1126/science.1126272 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 048QM UT WOS:000237961600044 PM 16741111 ER PT J AU Forbes, JM Bruinsma, S Lemoine, FG AF Forbes, JM Bruinsma, S Lemoine, FG TI Solar rotation effects on the thermospheres of Mars and Earth SO SCIENCE LA English DT Article ID DENSITIES; IONOSPHERE; MODEL; FLUX AB The responses of Earth's and Mars' thermospheres to the quasi-periodic (27-day) variation of solar flux due to solar rotation were measured contemporaneously, revealing that this response is twice as large for Earth as for Mars. Per typical 20-unit change in 10.7-centimeter radio flux ( used as a proxy for extreme ultraviolet flux) reaching each planet, we found temperature changes of 42.0 +/- 8.0 kelvin and 19.2 +/- 3.6 kelvin for Earth and Mars, respectively. Existing data for Venus indicate values of 3.6 +/- 0.6 kelvin. Our observational result constrains comparative planetary thermosphere simulations and may help resolve existing uncertainties in thermal balance processes, particularly CO2 cooling. C1 Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. CNES, Dept Terr & Planetary Geodesy, F-31401 Toulouse, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Forbes, JM (reprint author), Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. EM forbes@colorado.edu RI Lemoine, Frank/D-1215-2013; OI FORBES, JEFFREY/0000-0001-6937-0796 NR 15 TC 43 Z9 46 U1 0 U2 2 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 JUN 2 PY 2006 VL 312 IS 5778 BP 1366 EP 1368 DI 10.1126/science.1126389 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 048QM UT WOS:000237961600051 PM 16741117 ER PT J AU Rankenburg, K Brandon, AD Neal, CR AF Rankenburg, K Brandon, AD Neal, CR TI Neodymium isotope evidence for a chondritic composition of the Moon SO SCIENCE LA English DT Article ID HF-W CHRONOMETRY; LUNAR DIFFERENTIATION; ND-142 EVIDENCE; EARTHS MANTLE; SOLAR-SYSTEM; GIANT IMPACT; MARE BASALTS; CONSTRAINTS; EVOLUTION; ORIGIN AB Samarium-neodymium isotope data for six lunar basalts show that the bulk Moon has a Nd-142/Nd-144 ratio that is indistinguishable from that of chondritic meteorites but is 20 parts per million less than most samples from Earth. The Sm/Nd formation interval of the lunar mantle from these data is 215(-21)(+23) million years after the onset of solar system condensation. Because both Earth and the Moon likely formed in the same region of the solar nebula, Earth should also have a chondritic bulk composition. In order to mass balance the Nd budget, these constraints require that a complementary reservoir with a lower Nd-142/Nd-144 value resides in Earth's mantle. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Notre Dame, Dept Civil Engn & Geol Sci, Notre Dame, IN 46556 USA. RP Rankenburg, K (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code KR, Houston, TX 77058 USA. EM kai.rankenburg1@jsc.nasa.gov NR 38 TC 68 Z9 74 U1 2 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 JUN 2 PY 2006 VL 312 IS 5778 BP 1369 EP 1372 DI 10.1126/science.1126114 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 048QM UT WOS:000237961600052 PM 16741118 ER PT J AU Rayman, MD Fraschetti, TC Raymond, CA Russell, CT AF Rayman, MD Fraschetti, TC Raymond, CA Russell, CT TI Dawn: A mission in development for exploration of main belt asteroids Vesta and Ceres SO ACTA ASTRONAUTICA LA English DT Article ID GAMMA-RAY; SPECTROMETER; SPACE AB Dawn is in development for a mission to explore main belt asteroids in order to yield insights into important questions about the formation and evolution of the solar system. Its objective is to acquire data from orbit around two complementary bodies, (4) Vesta and (1) Ceres, the two most massive asteroids. The project relies on extensive heritage from other deep-space and Earth-orbiting missions, thus permitting the ambitious objectives to be accomplished with an affordable budget. (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 11 TC 76 Z9 77 U1 1 U2 6 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 JUN PY 2006 VL 58 IS 11 BP 605 EP 616 DI 10.1016/j.actaastro.2006.01.014 PG 12 WC Engineering, Aerospace SC Engineering GA 046NE UT WOS:000237817500006 ER PT J AU Fernandez, MM Vilnrotter, VA AF Fernandez, MM Vilnrotter, VA TI Coherent optical array receiver for PPM signals under atmospheric turbulence SO ACTA ASTRONAUTICA LA English DT Article DE coherent optical communications; pulse position modulation; focal-plane array AB Adaptive combining of experimentally obtained heterodyned pulse position modulated (PPM) signals with pulse-to-pulse coherence, in the presence of simulated spatial distortions resembling atmospheric turbulence, is demonstrated. The adaptively combined PPM signals are phased up via an least-mean-square algorithm suitably optimized to operate with PPM in the presence of additive shot noise. A convergence analysis of the algorithm is presented, and results with both computer simulated and experimentally obtained PPM signals are analyzed. (C) 2006 Elsevier Ltd. All fights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fernandez, MM (reprint author), CALTECH, Jet Prop Lab, M-C 136-93, Pasadena, CA 91125 USA. EM michela@caltech.edu; Victor.A.Vilnrotter@jpt.nasa.gov NR 5 TC 0 Z9 0 U1 1 U2 1 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 JUN PY 2006 VL 58 IS 12 BP 633 EP 641 DI 10.1016/j.actaastro.2005.11.003 PG 9 WC Engineering, Aerospace SC Engineering GA 055OW UT WOS:000238461000003 ER PT J AU Ingham, MD Rasmussen, RD Bennett, MB Moncada, AC AF Ingham, Michel D. Rasmussen, Robert D. Bennett, Matthew B. Moncada, Alex C. TI Generating requirements for complex embedded systems using State Analysis SO ACTA ASTRONAUTICA LA English DT Article AB It has become clear that spacecraft system complexity is reaching a threshold where customary methods of control are no longer affordable or sufficiently reliable. At the heart of this problem are the conventional approaches to systems and software engineering based on subsystem-level functional decomposition, which fail to scale in the tangled web of interactions typically encountered in complex spacecraft designs. Furthermore, there is a fundamental gap between the requirements on software specified by systems engineers and the implementation of these requirements by software engineers. Software engineers must perform the translation of requirements into software code, hoping to accurately capture the systems engineer's understanding of the system behavior, which is not always explicitly specified. This gap opens up the possibility for misinterpretation of the systems engineer's intent, potentially leading to software errors. This problem is addressed by a systems engineering methodology called State Analysis, which provides a process for capturing system and software requirements in the form of explicit models. This paper describes how requirements for complex aerospace systems can be developed using State Analysis, using representative spacecraft examples. (C) 2006 International Astronautical Federation. Published by Elsevier Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ingham, MD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr M-S 301-225, Pasadena, CA 91109 USA. EM michel.d.ingham@jpl.nasa.govak; robert.d.rasmussen@jpl.nasa.gov; matthew.b.bennett@jpl.nasa.gov; alex.c.moncada@jpl.nasa.gov NR 10 TC 2 Z9 6 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 EI 1879-2030 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JUN PY 2006 VL 58 IS 12 BP 648 EP 661 DI 10.1016/j.actaastro.2006.01.005 PG 14 WC Engineering, Aerospace SC Engineering GA 055OW UT WOS:000238461000005 ER PT J AU Uzun, A Hussaini, MY Streett, CL AF Uzun, A Hussaini, MY Streett, CL TI Large-eddy simulation of a wing tip vortex on overset grids SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA/CEAS 11th Aeroacoustics Conference CY MAY 23-25, 2005 CL Monterey, CA SP AIAA, CEAS ID CHARACTERISTIC BOUNDARY-CONDITIONS; FINITE-DIFFERENCE SCHEMES; NAVIER-STOKES EQUATIONS; COMPACT SCHEMES; COMPUTATIONAL AEROACOUSTICS; NEAR-FIELD; FLOW; IMPLICIT; FORMULATION; PREDICTION AB A multiblock large-eddy simulation (LES) code with overset grid capability is reported on that has been developed primarily to study the tip vortex noise problem arising on rotating wind-turbine blades The LES code can also be used to simulate the tip vortices around nonrotating wing geometries typically found in aeronautical applications. It employs state-of-the-art compact finite differencing, implicit spatial filtering, and nonreflecting boundary conditions on free boundaries, as well as characteristic-type boundary conditions on solid walls. Highorder-accurate interpolation is used for the transfer of information among the individual component grids that make up the overset grid topology. The multiblock nature and the overset grid capability of the code allow high-order accurate numerical solutions in complex domains. Results for the tip vortex around a nonrotating wing with a rounded tip are presented to demonstrate the capability of the code. Comparisons of the numerical results with experimental data are also carried out. C1 Florida State Univ, Sch Computat Sci, Tallahassee, FL 32306 USA. NASA, Langley Res Ctr, Computat Aerosci Branch, Hampton, VA 23681 USA. RP Uzun, A (reprint author), Florida State Univ, Sch Computat Sci, Tallahassee, FL 32306 USA. NR 41 TC 11 Z9 11 U1 3 U2 7 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 JUN PY 2006 VL 44 IS 6 BP 1229 EP 1242 DI 10.2514/1.17999 PG 14 WC Engineering, Aerospace SC Engineering GA 059LK UT WOS:000238734100012 ER PT J AU Naughton, JW Viken, S Greenblatt, D AF Naughton, JW Viken, S Greenblatt, D TI Skin-friction measurements on the NASA hump model SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 24th Aerodynamic Measurement Technology and Ground Testing Conference CY JUN 28-JUL 01, 2004 CL Portland, OR SP AIAA ID FLOW AB The skin-friction distribution on a wall-mounted hump model has been obtained using oil-film interferometry. This effort is part of a larger study,to provide validation cases for simulations of unsteady flows. The challenges of using oil-film interferometry on this model, including model curvature and close camera proximity, are discussed. Skin-friction measurements are obtained over most of the hump model, including especially high-quality measurements in the separated and reattachment regions. These results highlight the method's ability to capture a wide range of skin friction including measurements in reverse-How and high-gradient regions. The wall skin-friction data are shown to complement other experimental data, and the use of independent skin friction measurements for scaling in wall-bounded flows is emphasized. A comparison with results from several computational simulations of the same flow is presented. The comparison indicates that, for the most part, the computations accurately predict the skin-friction ahead of separation, but fail to predict the reattachment point correctly, and thus the comparison in the separated and recovery regions of the flow is poor. The ability of the skin-friction measurements to pinpiont regions where the computation performs poorly in the neat-wall region is also presented. From these yesults, it is evident that independent skin-friction measurements should be a part. of all validation experiments conducted in wall-bounded flows. C1 Univ Wyoming, Aeronaut Labs, Dept Mech Engn, Laramie, WY 82071 USA. NASA, Langley Res Ctr, Flow Phys & Control Branch, Hampton, VA 23681 USA. RP Naughton, JW (reprint author), Univ Wyoming, Aeronaut Labs, Dept Mech Engn, Dept 3295,1000 E Univ Ave, Laramie, WY 82071 USA. NR 27 TC 13 Z9 14 U1 1 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 JUN PY 2006 VL 44 IS 6 BP 1255 EP 1265 DI 10.2514/1.14192 PG 11 WC Engineering, Aerospace SC Engineering GA 059LK UT WOS:000238734100014 ER PT J AU Rubio-Gayosso, I Platts, SH Duling, BR AF Rubio-Gayosso, I Platts, SH Duling, BR TI Reactive oxygen species mediate modification of glycocalyx during ischemia-reperfusion injury SO AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY LA English DT Article DE glycosaminoglycans; heparin-binding domain; xanthine oxidoreductase ID ENDOTHELIAL-CELL GLYCOCALYX; RED-BLOOD-CELLS; NADPH OXIDASE; XANTHINE-OXIDASE; SURFACE-LAYER; TNF-ALPHA; POLYMORPHONUCLEAR LEUKOCYTES; RECEPTOR ACTIVATION; CORONARY FLOW; FREE-RADICALS AB The glycocalyx (Gcx) is a complex and poorly understood structure covering the luminal surface of endothelial cells. It is known to be a determinant of vascular rheology and permeability and may be a key control site for the vascular injuries caused by ischemia-reperfusion (I/R). We used intravital-microscopy to evaluate the effects of I/R injury on two properties of Gcx in mouse cremasteric microvessels: exclusion of macromolecules (anionic-dextrans) and intracapillary distribution of red blood cells (RBC). In this model, the Gcx is rapidly modified by I/R injury with an increase in 70-kDa anionic-dextran penetration without measurable effect on the penetration of 580-kDa anionic-dextran or on RBC exclusion. The effects of I/R injury appear to be mediated by the rapid production of reactive oxygen species (ROS) because they are ameliorated by the addition of exogenous superoxide dismutase-catalase. Intravenous application of allopurinol or heparin also inhibited the effects of I/R injury, and we interpret efficacy of allopurinol as evidence for a role for xanthine-oxidoreductase (XOR) in the response to I/R injury. Heparin, which is hypothesized to displace XOR from a heparin-binding domain in the Gcx, reduced the effects of I/R. The effects of I/R injury were also partially prevented or fully reversed by the intravascular infusion of exogenous hyaluronan. These data demonstrate: 1) the liability of Gcx during I/R injury; 2) the importance of locally produced ROS in the injury to Gcx; and 3) the potential importance of heparin-binding sites in modulating the ROS production. Our findings further highlight the relations between glycosaminoglycans and the pathophysiology of Gcx in vivo. C1 Univ Virginia, Sch Med, Cardiovasc Res Ctr, Dept Mol Physiol & Biol Phys, Charlottesville, VA 22908 USA. Johnson Space Ctr, Natl Aeronaut & Space Ctr, Div Space Life Sci, Space Res Assoc, Houston, TX USA. RP Duling, BR (reprint author), Univ Virginia, Sch Med, Cardiovasc Res Ctr, Dept Mol Physiol & Biol Phys, 409 Lane Rd,MR-4 Bldg,Rm 6051, Charlottesville, VA 22908 USA. EM brd@virginia.edu RI Rubio-Gayosso, Ivan/E-9414-2013; OI Rubio-Gayosso, Ivan/0000-0001-8315-8572 FU NHLBI NIH HHS [HL 72864] NR 69 TC 81 Z9 86 U1 1 U2 8 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0363-6135 J9 AM J PHYSIOL-HEART C JI Am. J. Physiol.-Heart Circul. Physiol. PD JUN PY 2006 VL 290 IS 6 BP H2247 EP H2256 DI 10.1152/ajpheart.00796.2005 PG 10 WC Cardiac & Cardiovascular Systems; Physiology; Peripheral Vascular Disease SC Cardiovascular System & Cardiology; Physiology GA 040YQ UT WOS:000237419600015 PM 16399871 ER PT J AU Cao, YZ Hussaini, MY Zang, T Zatezalo, A AF Cao, YZ Hussaini, MY Zang, T Zatezalo, A TI A variance reduction method based on sensitivity derivatives SO APPLIED NUMERICAL MATHEMATICS LA English DT Article AB This paper establishes a general theoretical framework for variance reduction based on arbitrary order derivatives of the solution with respect to the random parameters, known as sensitivity derivatives. The theoretical results are validated by two examples-the solution of the Burgers equation with viscosity as a single random parameter, and a test case involving five random variables. These examples illustrate that the first-order sensitivity derivative variance reduction method achieves an order of magnitude improvement in accuracy for both Monte Carlo and stratified sampling schemes. The second-order sensitivity derivative method improves the accuracy by another order of magnitude relative to the first-order method. Coupling it with stratified sampling yields yet another order of magnitude improvement in accuracy. (c) 2005 IMACS. Published by Elsevier B.V. All rights reserved. C1 Florida A&M Univ, Dept Math, Tallahassee, FL 32307 USA. Florida State Univ, Sch Computat Sci & Informat Technol, Tallahassee, FL 32306 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Cao, YZ (reprint author), Florida A&M Univ, Dept Math, Tallahassee, FL 32307 USA. EM yanzhao.cao@famu.edu NR 16 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD JUN PY 2006 VL 56 IS 6 BP 800 EP 813 DI 10.1016/j.apnum.2005.06.010 PG 14 WC Mathematics, Applied SC Mathematics GA 037GR UT WOS:000237135600004 ER PT J AU Lau, J Fowler, J Marriage, T Page, L Leong, J Wishnow, E Henry, R Wollack, E Halpern, M Marsden, D Marsden, G AF Lau, Judy Fowler, Joseph Marriage, Tobias Page, Lyman Leong, Jon Wishnow, Edward Henry, Ross Wollack, Ed Halpern, Mark Marsden, Danica Marsden, Gaelen TI Millimeter-wave antireflection coating for cryogenic silicon lenses SO APPLIED OPTICS LA English DT Article ID FREQUENCIES; OPTICS AB We have developed and tested an antireflection (AR) coating method for silicon lenses used at cryogenic temperatures and millimeter wavelengths. Our particular application is a measurement of the cosmic microwave background. The coating consists of machined pieces of Cirlex glued to the silicon. The measured reflection from an AR-coated flat piece is less than 1.5% at the design wavelength. The coating has been applied to flats and lenses and has survived multiple thermal cycles from 300 to 4 K. We present the manufacturing method, the material properties, the tests performed, and estimates of the loss that can be achieved in practical lenses. (c) 2006 Optical Society of America. C1 Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Case Western Reserve Univ, Dept Phys, Cleveland, OH 44106 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NASA, Goddard Space Flight Ctr, Observ Cosmol Lab, Greenbelt, MD 20771 USA. Univ British Columbia, Dept Phys & Astron, Vancouver, BC V6T 1Z1, Canada. RP Lau, J (reprint author), Princeton Univ, Dept Phys, Jadwin Hall, Princeton, NJ 08544 USA. RI Wollack, Edward/D-4467-2012 OI Wollack, Edward/0000-0002-7567-4451 NR 13 TC 28 Z9 28 U1 0 U2 5 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUN 1 PY 2006 VL 45 IS 16 BP 3746 EP 3751 DI 10.1364/AO.45.003746 PG 6 WC Optics SC Optics GA 047EY UT WOS:000237863800010 PM 16724132 ER PT J AU Sterritt, R Hinchey, MG AF Sterritt, Roy Hinchey, Michael G. TI Editorial: Engineering autonomic systems SO ARTIFICIAL INTELLIGENCE REVIEW LA English DT Editorial Material C1 [Sterritt, Roy] Univ Ulster, Newtownabbey, Antrim, North Ireland. [Hinchey, Michael G.] NASA, Goddard Space Flight Ctr, Software Engn Lab, Greenbelt, MD 20771 USA. RP Sterritt, R (reprint author), Univ Ulster, Jordanstown Campus, Newtownabbey, Antrim, North Ireland. EM r.sterritt@ulster.ac.uk; michael.g.hinchey@nasa.gov NR 8 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0269-2821 J9 ARTIF INTELL REV JI Artif. Intell. Rev. PD JUN PY 2006 VL 25 IS 4 BP 281 EP 284 DI 10.1007/s10462-007-9030-9 PG 4 WC Computer Science, Artificial Intelligence SC Computer Science GA 241HY UT WOS:000251648700001 ER PT J AU Rash, JL Hinchey, MG Rouff, C Gracanin, D Erickson, J AF Rash, James L. Hinchey, Michael G. Rouff, ChristopherA. Gracanin, Denis Erickson, John TI A requirements-based programming approach to developing a NASA autonomous ground control system SO ARTIFICIAL INTELLIGENCE REVIEW LA English DT Article DE validation; verification; formal methods; automatic code generation; NASA; autonomous systems; autonomic systems AB A new requirements-based programming approach to the engineering of computer-based systems offers not only an underlying formalism, but also full formal development from requirements capture through to the automatic generation of provably-correct code. The method, Requirements-to-Design-to-Code (R2D2C), is directly applicable to the development of autonomous systems and systems having autonomic properties. We describe both the R2D2C method and a prototype tool that embodies the method, and illustrate the applicability of the method by describing how the prototype tool could be used in the development of LOGOS, a NASA autonomous ground control system that exhibits autonomic behavior. Finally, we briefly discuss other possible areas of application of the approach. C1 [Rash, James L.; Hinchey, Michael G.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Rouff, ChristopherA.] SAIC, Mclean, VA USA. [Gracanin, Denis] Virginia Tech, Blacksburg, VA USA. [Erickson, John] Univ Texas Austin, Austin, TX 78712 USA. RP Rash, JL (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM james.l.rash@nasa.gov; michael.g.hinchey@nasa.gov; rouffc@saic.com; gracanin@vt.edu; jderick@cs.utexas.edu NR 25 TC 4 Z9 4 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0269-2821 EI 1573-7462 J9 ARTIF INTELL REV JI Artif. Intell. Rev. PD JUN PY 2006 VL 25 IS 4 BP 285 EP 297 DI 10.1007/s10462-007-9029-2 PG 13 WC Computer Science, Artificial Intelligence SC Computer Science GA 241HY UT WOS:000251648700002 ER PT J AU Wierzchos, J Ascaso, C McKay, CP AF Wierzchos, J Ascaso, C McKay, CP TI Endolithic cyanobacteria in halite rocks from the hyperarid core of the Atacama Desert SO ASTROBIOLOGY LA English DT Article DE Atacama Desert; Chroococcidiopsis; endoliths; halite; Mars ID MICROBIAL LIFE; MARS; EVAPORITES; CHILE; MICROORGANISMS; HALOBACTERIA; ENVIRONMENTS; METEORITES; DEPOSITS; EARTH AB In the driest parts of the Atacama Desert there are no visible life forms on soil or rock surfaces. The soil in this region contains only minute traces of bacteria distributed in patches, and conditions are too dry for cyanobacteria that live under translucent stones. Here we show that halite evaporite rocks from the driest part of the Atacama Desert are colonized by cyanobacteria. This colonization takes place just a few millimeters beneath the rock surface, occupying spaces among salt crystals. Our work reveals that these communities are composed of extremely resistant Chroococcidiopsis morphospecies of cyanobacteria and associated heterotrophic bacteria. This newly discovered endolithic environment is an extremely dry and, at the same time, saline microbial habitat. Photosynthetic microorganisms within dry evaporite rocks could be an important and previously unrecognized target for the search for life within our Solar System. C1 Univ Lleida, Serv Microscopia Elect, Lleida 25198, Spain. CSIC, Inst Recursos Nat, Madrid, Spain. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Wierzchos, J (reprint author), Univ Lleida, Serv Microscopia Elect, C Rovira Roure 44, Lleida 25198, Spain. EM jacekw@suic-me.udl.es RI Ascaso, Carmen/F-5369-2011; Wierzchos, Jacek/F-7036-2011 OI Ascaso, Carmen/0000-0001-9665-193X; Wierzchos, Jacek/0000-0003-3084-3837 NR 27 TC 120 Z9 130 U1 6 U2 43 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 JUN PY 2006 VL 6 IS 3 BP 415 EP 422 DI 10.1089/ast.2006.6.415 PG 8 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 059EK UT WOS:000238715900003 PM 16805697 ER PT J AU Cooper, JF Johnson, RE Richardson, JD Leblanc, F AF Cooper, JF Johnson, RE Richardson, JD Leblanc, F TI Space physics, Mars, and life SO ASTROBIOLOGY LA English DT Editorial Material ID ATMOSPHERE; METHANE C1 NASA, Goddard Space Flight Ctr, Space Phys Data Facil, Greenbelt, MD 20771 USA. Univ Virginia, Dept Mat Sci & Engn, Charlottesville, VA USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. CNRS, Serv Aeron, F-91371 Verrieres Le Buisson, France. RP Cooper, JF (reprint author), NASA, Goddard Space Flight Ctr, Space Phys Data Facil, Code 612-4, Greenbelt, MD 20771 USA. EM John.F.Cooper@nasa.gov RI Cooper, John/D-4709-2012 NR 9 TC 2 Z9 2 U1 1 U2 5 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 JUN PY 2006 VL 6 IS 3 BP 437 EP 438 DI 10.1089/ast.2006.6.437 PG 2 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 059EK UT WOS:000238715900005 PM 16805699 ER PT J AU Atreya, SK Wong, AS Renno, NO Farrell, WM Delory, GT Sentman, DD Cummer, SA Marshall, JR Rafkin, SCR Catling, DC AF Atreya, SK Wong, AS Renno, NO Farrell, WM Delory, GT Sentman, DD Cummer, SA Marshall, JR Rafkin, SCR Catling, DC TI Oxidant enhancement in martian dust devils and storms: Implications for life and habitability SO ASTROBIOLOGY LA English DT Article DE Mars; oxidants; hydrogen peroxide; triboelectricity; electrostatic fields; dust devils; dust storms; saltation; organics; methane; habitability; life ID MARS; ATMOSPHERE; MODEL; PHOTOCHEMISTRY; STABILITY; HYDROGEN; METHANE; SURFACE; CLOUDS; H2O2 AB We investigate a new mechanism for producing oxidants, especially hydrogen peroxide (H2O2), on Mars. Large-scale electrostatic fields generated by charged sand and dust in the martian dust devils and storms, as well as during normal saltation, can induce chemical changes near and above the surface of Mars. The most dramatic effect is found in the production of H2O2 whose atmospheric abundance in the "vapor" phase can exceed 200 times that produced by photochemistry alone. With large electric fields, H2O2 abundance gets large enough for condensation to occur, followed by precipitation out of the atmosphere. Large quantities of H2O2 would then be adsorbed into the regolith, either as solid H2O2 "dust" or as re-evaporated vapor if the solid does not survive as it diffuses from its production region close to the surface. We suggest that this H2O2, or another superoxide processed from it in the surface, may be responsible for scavenging organic material from Mars. The presence of H2O2 in the surface could also accelerate the loss of methane from the atmosphere, thus requiring a larger source for maintaining a steady-state abundance of methane on Mars. The surface oxidants, together with storm electric fields and the harmful ultraviolet radiation that readily passes through the thin martian atmosphere, are likely to render the surface of Mars inhospitable to life as we know it. C1 Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Alaska, Inst Geophys, Fairbanks, AK USA. Duke Univ, Dept Elect & Comp Engn, Durham, NC USA. SETI Inst, Mountain View, CA USA. SW Res Inst, Boulder, CO USA. Univ Washington, Dept Atmospher Sci, Astrobiol Program, Seattle, WA 98195 USA. Univ Bristol, Dept Earth Sci, Bristol, Avon, England. RP Atreya, SK (reprint author), Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. EM atreya@umich.edu RI Cummer, Steven/A-6118-2008; Catling, David/D-2082-2009; Farrell, William/I-4865-2013; OI Cummer, Steven/0000-0002-0002-0613; Catling, David/0000-0001-5646-120X NR 47 TC 81 Z9 83 U1 5 U2 22 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 JUN PY 2006 VL 6 IS 3 BP 439 EP 450 DI 10.1089/ast.2006.6.439 PG 12 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 059EK UT WOS:000238715900006 PM 16805700 ER PT J AU Delory, GT Farrell, WM Atreya, SK Renno, NO Wong, AS Cummer, SA Sentman, DD Marshall, JR Rafkin, SCR Catling, DC AF Delory, GT Farrell, WM Atreya, SK Renno, NO Wong, AS Cummer, SA Sentman, DD Marshall, JR Rafkin, SCR Catling, DC TI Oxidant enhancement in martian dust devils and storms: Storm electric fields and electron dissociative attachment SO ASTROBIOLOGY LA English DT Article DE Mars; dust storm; dust devil; electric field; oxidant; habitability ID ART. NO. E03004; CROSS-SECTIONS; SURFACE-CHEMISTRY; RED SPRITES; BLUE JETS; MARS; ATMOSPHERE; MODEL; IONOSPHERE; DISCHARGES AB Laboratory studies, numerical simulations, and desert field tests indicate that aeolian dust transport can generate atmospheric electricity via contact electrification or "triboelectricity." In convective structures such as dust devils and dust storms, grain stratification leads to macroscopic charge separations and gives rise to an overall electric dipole moment in the aeolian feature, similar in nature to the dipolar electric field generated in terrestrial thunderstorms. Previous numerical simulations indicate that these storm electric fields on Mars can approach the ambient breakdown field strength of similar to 25 kV/m. In terrestrial dust phenomena, potentials ranging from similar to 20 to 160 kV/m have been directly measured. The large electrostatic fields predicted in martian dust devils and storms can energize electrons in the low pressure martian atmosphere to values exceeding the electron dissociative attachment energy of both CO2 and H2O, which results in the formation of the new chemical products CO/O- and OH/H-, respectively. Using a collisional plasma physics model, we present calculations of the CO/O- and OH/H- reaction and production rates. We demonstrate that these rates vary geometrically with the ambient electric field, with substantial production of dissociative products when fields approach the breakdown value of similar to 25 kV/m. The dissociation of H2O into OH/H- provides a key ingredient for the generation of oxidants; thus electrically charged dust may significantly impact the habitability of Mars. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Duke Univ, Dept Elect & Comp Engn, Durham, NC USA. Univ Alaska, Inst Geophys, Fairbanks, AK USA. SETI Inst, Mountain View, CA USA. SW Res Inst, Boulder, CO USA. Univ Washington, Dept Atmospher Sci, Astrobiol Program, Seattle, WA 98195 USA. Univ Bristol, Dept Earth Sci, Bristol, Avon, England. RP Delory, GT (reprint author), Univ Calif Berkeley, Space Sci Lab, MS 7450, Berkeley, CA 94720 USA. EM gdelory@ssl.berkeley.edu RI Cummer, Steven/A-6118-2008; Catling, David/D-2082-2009; Farrell, William/I-4865-2013; OI Cummer, Steven/0000-0002-0002-0613; Catling, David/0000-0001-5646-120X NR 54 TC 54 Z9 56 U1 4 U2 22 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 JUN PY 2006 VL 6 IS 3 BP 451 EP 462 DI 10.1089/ast.2006.6.451 PG 12 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 059EK UT WOS:000238715900007 PM 16805701 ER PT J AU Hand, KP Chyba, CF Carlson, RW Cooper, JF AF Hand, KP Chyba, CF Carlson, RW Cooper, JF TI Clathrate hydrates of oxidants in the ice shell of Europa SO ASTROBIOLOGY LA English DT Article DE Europa; clathrate hydrates; radiolysis ID INFRARED MAPPING SPECTROMETER; OUTER SOLAR-SYSTEM; GALILEAN SATELLITES; OPTICAL-PROPERTIES; SULFURIC-ACID; WATER-ICE; NEUTRON-DIFFRACTION; RAMAN-SPECTROSCOPY; HYDROGEN-PEROXIDE; AIR-CLATHRATE AB Europa's icy surface is radiolytically modified by high-energy electrons and ions, and photolytically modified by solar ultraviolet photons. Observations from the Galileo Near Infrared Mapping Spectrometer, ground-based telescopes, the International Ultraviolet Explorer, and the Hubble Space Telescope, along with laboratory experiment results, indicate that the production of oxidants, such as H2O2, O-2, CO2, and SO2, is a consequence of the surface radiolytic chemistry. Once created, some of the products may be entrained deeper into the ice shell through impact gardening or other resurfacing processes. The temperature and pressure environments of regions within the europan hydrosphere are expected to permit the formation of mixed clathrate compounds. The formation of carbon dioxide and sulfur dioxide clathrates has been examined in some detail. Here we add to this analysis by considering oxidants produced radiolytically on the surface of Europa. Our results indicate that the bulk ice shell could have a similar to 1.7-7.6% by number contamination of oxidants resulting from radiolysis at the surface. Oxidant-hosting clathrates would consequently make up similar to 12-53% of the ice shell by number relative to ice, if oxidants were entrained throughout. We examine, in brief, the consequences of such contamination on bulk ice shell thickness and find that clathrate formation could lead to substantially thinner ice shells on Europa than otherwise expected. Finally, we propose that double occupancy of clathrate cages by O-2 molecules could serve as an explanation for the observation of condensed-phase O-2 on Europa. Clathrate-sealed, gas-filled bubbles in the near surface ice could also provide an effective trapping mechanism, though they cannot explain the 5771 angstrom (O-2)(2) absorption. C1 Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. SETI Inst, Mountain View, CA USA. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. NASA, Jet Prop Lab, Pasadena, CA USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hand, KP (reprint author), Stanford Univ, Dept Geol & Environm Sci, 450 Serra Mall,Bldg 320, Stanford, CA 94305 USA. EM khand@stanford.edu RI Cooper, John/D-4709-2012 NR 78 TC 33 Z9 33 U1 1 U2 19 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 JUN PY 2006 VL 6 IS 3 BP 463 EP 482 DI 10.1089/ast.2006.6.463 PG 20 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 059EK UT WOS:000238715900008 PM 16805702 ER PT J AU Hudson, RL Moore, MH AF Hudson, RL Moore, MH TI Infrared spectra and radiation stability of H2O2 ices relevant to Europa SO ASTROBIOLOGY LA English DT Article DE Europa; hydrogen peroxide; radiation effects; infrared spectra ID HYDROGEN-PEROXIDE; ION IRRADIATION; WATER ICE; GALILEAN SATELLITES; INTERSTELLAR; SURFACE; D2O2 AB In this paper we present spectra of H2O2-Containing ices in the near- and mid-infrared (IR) regions. Spectral changes on warming are shown, as is a comparison of near-IR bands of H2O and H2O2-Containing ices. An estimate of the A-value (absolute intensity) for the largest near-IR feature of H2O2 is given. Radiation-decay half-lives are reported for 19 K and 80 K, and are related to the surface radiation doses on Europa. The radiation data show that H2O2 destruction is slower at 80 K than 19 K, and are consistent with the claim that icy material in the outermost micrometer of Europa's surface has been heavily processed by radiation. C1 Eckerd Coll, Dept Chem, St Petersburg, FL 33711 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hudson, RL (reprint author), Eckerd Coll, Dept Chem, 4200 54th Ave S, St Petersburg, FL 33711 USA. EM hudsonrl@eckerd.edu RI Hudson, Reggie/E-2335-2012 NR 25 TC 11 Z9 11 U1 2 U2 8 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 JUN PY 2006 VL 6 IS 3 BP 483 EP 489 DI 10.1089/ast.2006.6.483 PG 7 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 059EK UT WOS:000238715900009 PM 16805703 ER PT J AU Ridge, NA Di Francesco, J Kirk, H Li, D Goodman, AA Alves, JF Arce, HG Borkin, MA Caselli, P Foster, JB Heyer, MH Johnstone, D Kosslyn, DA Lombardi, M Pineda, JE Schnee, SL Tafalla, M AF Ridge, NA Di Francesco, J Kirk, H Li, D Goodman, AA Alves, JF Arce, HG Borkin, MA Caselli, P Foster, JB Heyer, MH Johnstone, D Kosslyn, DA Lombardi, M Pineda, JE Schnee, SL Tafalla, M TI The COMPLETE Survey of Star-Forming Regions: Phase I data SO ASTRONOMICAL JOURNAL LA English DT Article DE ISM : clouds; stars : formation; surveys ID DARK CLOUD COMPLEX; INTERSTELLAR EXTINCTION; MAGNETIC-FIELD; EMISSION MAPS; PERSEUS; DUST; DENSITY; MICRONS AB We present an overview of data available for the Ophiuchus and Perseus molecular clouds from Phase I of the COMPLETE Survey of Star-Forming Regions. This survey provides a range of data complementary to the Spitzer Legacy Program "From Molecular Cores to Planet Forming Disks.'' Phase I includes the following: extinction maps derived from the Two Micron All Sky Survey (2MASS) near-infrared data using the NICER algorithm; extinction and temperature maps derived from IRAS 60 and 100 mu m emission; H I maps of atomic gas; (CO)-C-12 and (CO)-C-13 maps of molecular gas; and submillimeter continuum images of emission from dust in dense cores. Not unexpectedly, the morphology of the regions appears quite different depending on the column density tracer that is used, with IRAS tracing mainly warmer dust and CO being biased by chemical, excitation, and optical depth effects. Histograms of column density distribution are presented, showing that extinction as derived from 2MASS NICER gives the closest match to a lognormal distribution, as is predicted by numerical simulations. All the data presented in this paper, and links to more detailed publications on their implications, are publicly available at the COMPLETE Web site. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Herzberg Inst Astrophys, Natl Res Council Canada, Victoria, BC V9E 2E7, Canada. Univ Victoria, Dept Phys & Astron, Victoria, BC V8P 1A1, Canada. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. European So Observ, D-85748 Garching, Germany. Amer Museum Nat Hist, Dept Astrophys, New York, NY 10024 USA. Harvard Univ, Dept Astron, Cambridge, MA 02138 USA. Osserv Astrofis Arcetri, INAF, I-50125 Florence, Italy. Univ Massachusetts, Dept Astron, Lederle Grad Res Ctr, Amherst, MA 01003 USA. Observ Astron Nacl, E-28014 Madrid, Spain. RP Ridge, NA (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Pineda, Jaime/J-7405-2013; Goodman, Alyssa/A-6007-2010; OI Pineda, Jaime/0000-0002-3972-1978; Goodman, Alyssa/0000-0003-1312-0477; Johnstone, Doug/0000-0002-6773-459X; LOMBARDI, MARCO/0000-0002-3336-4965; Alves, Joao/0000-0002-4355-0921 NR 28 TC 147 Z9 147 U1 1 U2 7 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 JUN PY 2006 VL 131 IS 6 BP 2921 EP 2933 DI 10.1086/503704 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 051QT UT WOS:000238176400013 ER PT J AU Golimowski, DA Ardila, DR Krist, JE Clampin, M Ford, HC Illingworth, GD Bartko, F Benitez, N Blakeslee, JP Bouwens, RJ Bradley, LD Broadhurst, TJ Brown, RA Burrows, CJ Cheng, ES Cross, NJG Demarco, R Feldman, PD Franx, M Goto, T Gronwall, C Hartig, GF Holden, BP Homeier, NL Infante, L Jee, MJ Kimble, RA Lesser, MP Martel, AR Mei, S Menanteau, F Meurer, GR Miley, GK Motta, V Postman, M Rosati, P Sirianni, M Sparks, WB Tran, HD Tsvetanov, ZI White, RL Zheng, W Zirm, AW AF Golimowski, D. A. Ardila, D. R. Krist, J. E. Clampin, M. Ford, H. C. Illingworth, G. D. Bartko, F. Benitez, N. Blakeslee, J. P. Bouwens, R. J. Bradley, L. D. Broadhurst, T. J. Brown, R. A. Burrows, C. J. Cheng, E. S. Cross, N. J. G. Demarco, R. Feldman, P. D. Franx, M. Goto, T. Gronwall, C. Hartig, G. F. Holden, B. P. Homeier, N. L. Infante, L. Jee, M. J. Kimble, R. A. Lesser, M. P. Martel, A. R. Mei, S. Menanteau, F. Meurer, G. R. Miley, G. K. Motta, V. Postman, M. Rosati, P. Sirianni, M. Sparks, W. B. Tran, H. D. Tsvetanov, Z. I. White, R. L. Zheng, W. Zirm, A. W. TI Hubble Space Telescope ACS multiband coronagraphic imaging of the debris disk around beta pictoris SO ASTRONOMICAL JOURNAL LA English DT Article DE circumstellar matter; planetary systems : formation; planetary systems : protoplanetary disks; stars : individual (beta Pictoris) ID KUIPER-BELT OBJECTS; CIRCUMSTELLAR DUST DISK; ADVANCED CAMERA; MIDINFRARED SPECTROSCOPY; STELLAR ENCOUNTERS; OPTICAL-PROPERTIES; INFALLING COMETS; COLOR DIVERSITY; AU-MICROSCOPII; SYSTEM AB We present F435W(B), F606W (broad V), and F814W(broad I) coronagraphic images of the debris disk around beta Pictoris obtained with the Hubble Space Telescope's Advanced Camera for Surveys. These images provide the most photometrically accurate and morphologically detailed views of the disk between 30 and 300 AU from the star ever recorded in scattered light. We confirm that the previously reported warp in the inner disk is a distinct secondary disk inclined by similar to 5 degrees from the main disk. The projected spine of the secondary disk coincides with the isophotal inflections, or "butterfly asymmetry,'' previously seen at large distances from the star. We also confirm that the opposing extensions of the main disk have different position angles, but we find that this "wing-tilt asymmetry'' is centered on the star rather than offset from it, as previously reported. The main disk's northeast extension is linear from 80 to 250 AU, but the southwest extension is distinctly bowed with an amplitude of similar to 1 AU over the same region. Both extensions of the secondary disk appear linear, but not collinear, from 80 to 150 AU. Within similar to 120 AU of the star, the main disk is similar to 50% thinner than previously reported. The surface brightness profiles along the spine of the main disk are fitted with four distinct radial power laws between 40 and 250 AU, while those of the secondary disk between 80 and 150 AU are fitted with single power laws. These discrepancies suggest that the two disks have different grain compositions or size distributions. The F606W/F435W and F814W/F435W flux ratios of the composite disk are nonuniform and asymmetric about both projected axes of the disk. The disk's northwest region appears 20%-30% redder than its southeast region, which is inconsistent with the notion that forward scattering from the nearer northwest side of the disk should diminish with increasing wavelength. Within similar to 120 AU, the m(F435W)-m(F606W) and m(F435W)-m(F814W) colors along the spine of the main disk are similar to 10% and similar to 20% redder, respectively, than those of beta Pic. These colors increasingly redden beyond similar to 120 AU, becoming 25% and 40% redder, respectively, than the star at 250 AU. These measurements overrule previous determinations that the disk is composed of neutrally scattering grains. The change in color gradient at similar to 120 AU nearly coincides with the prominent inflection in the surface brightness profile at similar to 115 AU and the expected water-ice sublimation boundary. We compare the observed red colors within similar to 120 AU with the simulated colors of nonicy grains having a radial number density alpha r(-3) and different compositions, porosities, and minimum grain sizes. The observed colors are consistent with those of compact or moderately porous grains of astronomical silicate and/or graphite with sizes greater than or similar to 0.15-0.20 mu m, but the colors are inconsistent with the blue colors expected from grains with porosities greater than or similar to 90%. The increasingly red colors beyond the ice sublimation zone may indicate the condensation of icy mantles on the refractory grains, or they may reflect an increasing minimum grain size caused by the cessation of cometary activity. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. CALTECH, Ctr Infrared Proc & Anal, Spitzer Sci Ctr, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. Bartko Sci & Technol, Brighton, CO 80602 USA. CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain. Washington State Univ, Dept Phys & Astron, Pullman, WA 99164 USA. Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Metajiva, Edmonds, WA 98026 USA. Conceptual Anal LLC, Glenn Dale, MD 20769 USA. Royal Observ, Edinburgh EH9 3HJ, Midlothian, Scotland. Leiden Observ, NL-2300 RA Leiden, Netherlands. Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago 22, Chile. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. European So Observ, D-85748 Garching, Germany. WM Keck Observ, Kamuela, HI 96743 USA. RP Golimowski, DA (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. RI White, Richard/A-8143-2012; Clampin, mark/D-2738-2012; Kimble, Randy/D-5317-2012; OI tran, hien/0000-0001-7548-6664 NR 86 TC 112 Z9 112 U1 0 U2 6 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 JUN PY 2006 VL 131 IS 6 BP 3109 EP 3130 DI 10.1086/503801 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 051QT UT WOS:000238176400028 ER PT J AU Bettarini, L Landi, S Rappazzo, FA Velli, M Opher, M AF Bettarini, L Landi, S Rappazzo, FA Velli, M Opher, M TI Tearing and Kelvin-Helmholtz instabilities in the heliospheric plasma SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE instabilities; magnetohydrodynamics (MHD); plasmas; methods : numerical; Sun : solar wind ID SLOW SOLAR-WIND; CORONAL STREAMER; CURRENT SHEET; JET; HELIOPAUSE; EVOLUTION; DYNAMICS; WAVES; SHOCK; SUN AB We used 2.5D simulations to analyze the magnetohydrodynamic instabilities arising from an initial equilibrium configuration consisting of a plasma jet or wake in the presence of a magnetic field with strong transverse gradients, such as those arising in the solar wind. Our analysis extends previous results by considering both a force-free equilibrium and a pressure-balance condition for a jet in a plasma sheet, along with arbitrary angles between the magnetic field and velocity field. In the force-free case, the jet/wake does not contain a neutral sheet but the field rotates through the flow to invert its polarity. The presence of a magnetic field component aligned with the jet/wake destroys the symmetric nature of the fastest growing modes, leading to asymmetrical wake acceleration (or, equivalently, jet deceleration). In the case of a jet, the instability properties depend both on the magnetic field and flow gradients, as well as on the length of the jet. The results are applied to the post-termination shock jet recently found in 3D global heliospheric simulations, where our analysis confirms and explains the stability properties found in such simulations. C1 Univ Florence, Dept Astron & Space Sci, I-50125 Florence, Italy. Univ Pisa, Dept Phys, I-56127 Pisa, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bettarini, L (reprint author), Univ Florence, Dept Astron & Space Sci, I-50125 Florence, Italy. EM betta@arcetri.astro.it RI Landi, Simone/G-7282-2015 OI Landi, Simone/0000-0002-1322-8712 NR 40 TC 15 Z9 15 U1 1 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 JUN PY 2006 VL 452 IS 1 BP 321 EP 330 DI 10.1051/0004-6361:20054285 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 044EB UT WOS:000237654100035 ER PT J AU Godet, O Page, KL Osborne, JP O'Brien, PT Burrows, DN Hill, JE Zhang, B Beardmore, AP Angelini, L Capalbi, M Cummings, J Gehrels, N Goad, MR Kennea, JA Mangano, V Moretti, A Morris, DC AF Godet, O Page, KL Osborne, JP O'Brien, PT Burrows, DN Hill, JE Zhang, B Beardmore, AP Angelini, L Capalbi, M Cummings, J Gehrels, N Goad, MR Kennea, JA Mangano, V Moretti, A Morris, DC TI X-ray flares in the early Swift observations of the possible naked gamma-ray burst 050421 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma ray : bursts ID BATSE OBSERVATIONS; BURST AFTERGLOWS; TELESCOPE; VARIABILITY; SPECTRA; MISSION; CATALOG; BRIGHT; SHOCKS; GALAXY AB We present the Swift observations of the faint burst GRB 050421. The X-ray light-curve shows at least two flares: the first flare peaking at similar to 110 s after the BAT trigger (T-0) and the second one peaking at similar to 154 s. The first flare presents a flux variation of delta F/Fpeak similar to 3.7 and a short timescale ratio delta t/t(peak) similar to 0.07. The second flare is smaller and presents a flux variation of delta F/F-peak similar to 1.7 and a short timescale ratio delta t/t(peak) similar to 0.03. We argue that the mechanism producing these flares is probably late internal shocks. The X-ray light-curve is consistent with a rapid decline with a temporal index alpha similar to 3.1, which decays from similar to 10(-9) erg cm(-2) s(-1) at T-0 + 100 s to < 7 x 10(-13) erg cm(-2) s(-1) at T-0 + 900 s. A possible spectral softening is also observed with time, from beta similar to 0.1 to similar to 1.2. A good joint fit to the BAT and XRT spectra before T-0 + 171 s with beta(XRT-BAT) similar to 0.2 indicates that the early X-ray and Gamma-ray emissions are likely produced by the same mechanism. We argue that the X-ray spectral softening, if any, is due to a shift of the peak of the prompt emission spectrum down to lower energies, and that the rapid decline of the X-ray emission is probably the tail of the prompt emission. This suggests that the X-ray emission is completely dominated by high latitude radiation and the external shock, if any, is extremely faint and below the detection threshold. GRB 050421 is likely the first "naked burst" detected by Swift. C1 Univ Leicester, Dept Phys & Astron, Xray & Observ Astron Grp, Leicester LE1 7RH, Leics, England. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. ASI Sci Data Ctr, I-00044 Frascati, Italy. INAF, Ist Astrofis Spaz & Fis Cosm, Sez Palermo, I-90146 Palermo, Italy. INAF, Osservatorio Astron Brerea, I-23807 Merate, LC, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CNR, Washington, DC 20418 USA. Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. RP Godet, O (reprint author), Univ Leicester, Dept Phys & Astron, Xray & Observ Astron Grp, Leicester LE1 7RH, Leics, England. EM og19@star.le.ac.uk RI Gehrels, Neil/D-2971-2012; OI moretti, alberto/0000-0002-9770-0315 NR 49 TC 24 Z9 24 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 JUN PY 2006 VL 452 IS 3 BP 819 EP 825 DI 10.1051/0004-6361:20054435 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 050VU UT WOS:000238117900012 ER PT J AU Feissel-Vernier, M Ma, C Gontier, AM Barache, C AF Feissel-Vernier, M Ma, C Gontier, AM Barache, C TI Analysis strategy issues for the maintenance of the ICRF axes SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE astrometry; reference systems; galaxies : quasars : general ID CELESTIAL REFERENCE FRAME; RADIO-SOURCES AB In preparation for the evolution of the definition of the VLBI-based International Celestial Reference Frame ( ICRF), various elements of the analysis strategy are investigated, such as reference source selection and the impact of the status of the terrestrial reference frame in the data analysis model. We conclude that including the determination of both the celestial and the terrestrial reference frames in the analysis does not affect the quality of the celestial reference frame. The determination of precession and nutation components is not affected by the status of the terrestrial reference frame but it is affected by the selection of reference radio sources. Extending an earlier study, three lists of reference sources based on progressively larger tolerances are proposed. They include 181, 225 and 247 objects, respectively. C1 CNRS, Observ Paris, SYRTE, UMR 8630, F-75014 Paris, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Feissel-Vernier, M (reprint author), CNRS, Observ Paris, SYRTE, UMR 8630, 61 Av Observ, F-75014 Paris, France. EM mf.vernier@gmail.com; chopo.ma@nasa.gov; anne-marie.gontier@obspm.fr; christophe.barache@obspm.fr RI Ma, Chopo/D-4751-2012 NR 11 TC 15 Z9 16 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 JUN PY 2006 VL 452 IS 3 BP 1107 EP U83 DI 10.1051/0004-6361:20054581 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 050VU UT WOS:000238117900045 ER PT J AU Moretti, A De Luca, A Malesani, D Campana, S Tiengo, A Cucchiara, A Reeves, JN Chincarini, G Pagani, C Romano, P Tagliaferri, G Banat, P Capalbi, M Perri, M Cusumano, G Mangano, V Mineo, T La Parola, V Beardmore, A Goad, M Osborne, JP Hill, JE Angelini, L Burrows, DN Kobayashi, S Meszaros, P Zhang, B Barthelmy, SD Barbier, L White, NE Fenimore, EE Cominsky, LR Gehrels, N AF Moretti, A De Luca, A Malesani, D Campana, S Tiengo, A Cucchiara, A Reeves, JN Chincarini, G Pagani, C Romano, P Tagliaferri, G Banat, P Capalbi, M Perri, M Cusumano, G Mangano, V Mineo, T La Parola, V Beardmore, A Goad, M Osborne, JP Hill, JE Angelini, L Burrows, DN Kobayashi, S Meszaros, P Zhang, B Barthelmy, SD Barbier, L White, NE Fenimore, EE Cominsky, LR Gehrels, N TI Swift and XMM-Newton observations of the dark GRB 050326 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma rays : bursts; gamma rays : observations; X-rays : bursts ID GAMMA-RAY BURST; PHOTON IMAGING CAMERA; LIGHT CURVES; AFTERGLOW EMISSION; STAR-FORMATION; SUPERNOVA; REDSHIFT; DUST; ABSORPTION; TELESCOPE AB We present Swift and XMM-Newton observations of the bright gamma-ray burst GRB 050326, detected by the Swift Burst Alert Telescope. The Swift X-Ray Telescope (XRT) and XMM-Newton discovered the X- ray afterglow beginning 54 min and 8.5 h after the burst, respectively. The prompt GRB 050326 fluence was (7.7 +/- 0.9) x 10(-6) erg cm(-2) (20-150 keV), and its spectrum was hard, with a power law photon index Gamma = 1.25 +/- 0.03. The X-ray afterglow was quite bright, with a flux of 7 x 10(-11) erg cm(-2) s(-1) (0.3-8 keV), 1 h after the burst. Its light curve did not show any break nor flares between similar to 1 h and similar to 6 d after the burst, and decayed with a slope alpha = 1.70 +/- 0.05. The afterglow spectrum is well fitted by a power-law model, suffering absorption both in the Milky Way and in the host galaxy. The rest-frame hydrogen column density is significant, N-H,N-z > 4 x 10(21) cm(-2), and the redshift of the absorber was constrained to be z > 1.5. There was good agreement between the spatial, temporal, and spectral parameters as derived by Swift-XRT and XMM-Newton. By comparing the prompt and afterglow fluxes, we found that an early break probably occurred before the beginning of the XRT observation, similarly to many other cases observed by Swift. However, the properties of the GRB 050326 afterglow are well described by a spherical fireball expanding in a uniform external medium, so a further steepening is expected at later times. The lack of such a break allowed us to constrain the jet half-opening angle theta(j) greater than or similar to 7 degrees. Using the redshift constraints provided by the X- ray analysis, we also estimated that the beaming-corrected gamma-ray energy was larger than 3 x 10(51) erg, at the high end of GRB energies. Despite the brightness in X rays, only deep limits could be placed by Swift-UVOT at optical and ultraviolet wavelengths. Thus, this GRB was a "truly dark" event, with the optical-to-X-ray spectrum violating the synchrotron limit. The optical and X- ray observations are therefore consistent either with an absorbed event or with a high-redshift one. To obey the Ghirlanda relation, a moderate/large redshift z greater than or similar to 4.5 is required. C1 Osserv Astron Brera, INAF, I-23807 Merate, LC, Italy. Ist Astrofis Spaziale & Fis Cosm Milano, INAF, I-20133 Milan, Italy. ISAS, SISSA, I-34014 Trieste, Italy. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Milano Bicocca, Dipartimento Fis, I-20126 Milan, Italy. ASI Sci Data Ctr, I-00044 Frascati, Roma, Italy. Ist Astrofis Spaziale & Fis Cosm Palermo, INAF, I-90146 Palermo, Italy. Univ Leicester, Dept Phys & Astron, Xray Observat Astron Grp, Leicester LE1 7RH, Leics, England. Univ Space Res Assoc, Columbia, MD 21044 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Sonoma State Univ, Dept Phys & Astron, Rohnert Pk, CA 94928 USA. RP Moretti, A (reprint author), Osserv Astron Brera, INAF, Via E Bianchi 46, I-23807 Merate, LC, Italy. EM moretti@merate.mi.astro.it RI White, Nicholas/B-6428-2012; Gehrels, Neil/D-2971-2012; Barthelmy, Scott/D-2943-2012; OI White, Nicholas/0000-0003-3853-3462; La Parola, Valentina/0000-0002-8087-6488; De Luca, Andrea/0000-0001-6739-687X; Tagliaferri, Gianpiero/0000-0003-0121-0723; Mineo, Teresa/0000-0002-4931-8445; Tiengo, Andrea/0000-0002-6038-1090; Cusumano, Giancarlo/0000-0002-8151-1990; moretti, alberto/0000-0002-9770-0315; Perri, Matteo/0000-0003-3613-4409 NR 79 TC 1 Z9 1 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 JUN PY 2006 VL 451 IS 3 BP 777 EP 787 DI 10.1051/0004-6361:20053913 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 039TC UT WOS:000237329000013 ER PT J AU Severgnini, P Caccianiga, A Braito, V Della Ceca, R Maccacaro, T Akiyama, M Carrera, FJ Ceballos, MT Page, MJ Saracco, P Watson, MG AF Severgnini, P Caccianiga, A Braito, V Della Ceca, R Maccacaro, T Akiyama, M Carrera, FJ Ceballos, MT Page, MJ Saracco, P Watson, MG TI An X-ray bright ERO hosting a type 2 QSO SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : active; X-rays : galaxies; galaxies : individual : XBS J0216-0435 ID ACTIVE GALACTIC NUCLEI; CHANDRA DEEP-FIELD; XMM-NEWTON OBSERVATIONS; EXTREMELY RED OBJECTS; LUMINOSITY FUNCTION; HELLAS2XMM SURVEY; NORTH SURVEY; GALAXIES; EVOLUTION; EMISSION AB We present the XMM-Newton and the optical-VLT spectra along with the optical and the near-infrared photometric data of one of the brightest X-ray (F(2-10) keV similar to 10(-13) erg s(-1) cm(-2)) extremely red objects (R-K >= 5) discovered so far. The source, XBS J0216-0435, belongs to the XMM-Newton Bright Serendipitous Survey and it has extreme X-ray-to-optical (similar to 220) and X-ray-to-near-infrared (similar to 60) flux ratios. Thanks to its brightness, the X-ray statistics are good enough for an accurate spectral analysis by which the presence of an X-ray obscured (N(H) > 10(22) cm(-2)) QSO (L(2-10) keV = 4 x 10(45) erg s(-1)) is determined. A statistically significant (similar to 99%) excess around 2 keV in the observed-frame suggests the presence of an emission line. By assuming that this feature corresponds to the iron K alpha line at 6.4 keV, a first estimate of the redshift of the source is derived (zX similar to 2). The presence of a high redshift QSO2 has been finally confirmed through dedicated VLT optical spectroscopic observations (z(O) = 1.985 +/- 0.002). This result yields to an optical validation of a new X-ray Line Emitting Object ( XLEO) for which the redshift has been firstly derived from the X-ray data. XBS J0216-0435 can be considered one of the few examples of X-ray obscured QSO2 at high redshift for which a detailed X-ray and optical spectral analysis has been possible. The spectral energy distribution from radio to X-rays is also presented. Finally from the near-infrared data the luminosity and the stellar mass of the host galaxy has been estimated finding a new example of the coexistence at high-z between massive galaxies and powerful QSOs. C1 Osserv Astron Brera, INAF, I-20121 Milan, Italy. NASA, Goddard Space Flight Ctr, Explorat Universe Div, Greenbelt, MD 20771 USA. Natl Astron Observ Japan, Subaru Telescope, Hilo, HI 96720 USA. Univ Cantabria, CSIC, Inst Fis Cantabria, E-39005 Santander, Spain. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Univ Leicester, Dept Phys & Astron, Xray Astron Grp, Leicester LE1 7RH, Leics, England. RP Severgnini, P (reprint author), Osserv Astron Brera, INAF, Via Brera 28, I-20121 Milan, Italy. EM paola@brera.mi.astro.it; caccia@brera.mi.astro.it; braito@brera.mi.astro.it; rdc@brera.mi.astro.it; tommaso@brera.mi.astro.it; akiyama@subaru.naoj.org; carreraf@ifca.unican.es; ceballos@ifca.unican.es; mjp@mssl.ucl.ac.uk; saracco@brera.mi.astro.it; mgw@star.le.ac.uk RI Ceballos, Maria Teresa/K-9140-2014; OI Saracco, Paolo/0000-0003-3959-2595; Ceballos, Maria Teresa/0000-0001-6074-3621; Severgnini, Paola/0000-0001-5619-5896; Della Ceca, Roberto/0000-0001-7551-2252; Caccianiga, Alessandro/0000-0002-2339-8264; Braito, Valentina/0000-0002-2629-4989 NR 55 TC 17 Z9 17 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 JUN PY 2006 VL 451 IS 3 BP 859 EP 864 DI 10.1051/0004-6361:20053980 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 039TC UT WOS:000237329000022 ER PT J AU Fynbo, JPU Starling, RLC Ledoux, C Wiersema, K Thone, CC Sollerman, J Jakobsson, P Hjorth, J Watson, D Vreeswijk, PM Moller, P Rol, E Gorosabel, J Naranen, J Wijers, RAMJ Bjornsson, G Ceron, JMC Curran, P Hartmann, DH Holland, ST Jensen, BL Levan, AJ Limousin, M Kouveliotou, C Nelemans, G Pedersen, K Priddey, RS Tanvir, NR AF Fynbo, JPU Starling, RLC Ledoux, C Wiersema, K Thone, CC Sollerman, J Jakobsson, P Hjorth, J Watson, D Vreeswijk, PM Moller, P Rol, E Gorosabel, J Naranen, J Wijers, RAMJ Bjornsson, G Ceron, JMC Curran, P Hartmann, DH Holland, ST Jensen, BL Levan, AJ Limousin, M Kouveliotou, C Nelemans, G Pedersen, K Priddey, RS Tanvir, NR TI Probing cosmic chemical evolution with gamma-ray bursts: GRB 060206 at z=4.048 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma rays : bursts; galaxies : high-redshift; galaxies : abundances; cosmology : observations ID LYMAN-ALPHA SYSTEMS; HIGH-REDSHIFT; HOST GALAXIES; PHYSICAL CONDITIONS; MOLECULAR-HYDROGEN; NEUTRAL GAS; LY-ALPHA; ABUNDANCES; UNIVERSE; SPECTROSCOPY AB Aims. We present early optical spectroscopy of the afterglow of the gamma-ray burst GRB060206 with the aim of determining the metallicity of the GRB absorber and the physical conditions in the circumburst medium. We also discuss how GRBs may be important complementary probes of cosmic chemical evolution. Methods. Absorption line study of the GRB afterglow spectrum. Results. We determine the redshift of the GRB to be z = 4.04795 +/- 0.00020. Based on the measurement of the neutral hydrogen column density from the damped Lyman-alpha line and the metal content from weak, unsaturated S II lines we derive a metallicity of [S/H] = -0.84 +/- 0.10. This is one of the highest metallicities measured from absorption lines at z similar to 4. From the very high column densities for the forbidden Si II*, O I*, and O I** lines we infer very high densities and low temperatures in the system. There is evidence for the presence of H-2 molecules with log N(H-2) similar to 17.0, translating into a molecular fraction of log f approximate to 3.5 with f = 2N(H-2)/(2N(H-2) + N(H-I)). Even if GRBs are only formed by single massive stars with metallicities below similar to 0.3 Z(circle dot), they could still be fairly unbiased tracers of the bulk of the star formation at z > 2. Hence, metallicities as derived for GRB060206 here for a complete sample of GRB afterglows will directly show the distribution of metallicities for representative star-forming galaxies at these redshifts. C1 Univ Copenhagen, Niels Bohr Inst, Dark Cosmol Ctr, DK-2100 Copenhagen, Denmark. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. European So Observ, Santiago 19001, Chile. Univ Chile, Dept Astron, Santiago, Chile. European So Observ, D-85748 Garching, Germany. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. Univ Helsinki, Observ, FIN-00014 Helsinki, Finland. Univ Iceland, Inst Sci, IS-107 Reykjavik, Iceland. Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Hertfordshire, Ctr Astrophys Res, Hatfield AL10 9AB, Herts, England. NASA, George C Marshall Space Flight Ctr, NSSTC, Huntsville, AL 35805 USA. Radboud Univ, Dept Astrophys, NL-6500 GL Nijmegen, Netherlands. RP Fynbo, JPU (reprint author), Univ Copenhagen, Niels Bohr Inst, Dark Cosmol Ctr, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark. EM jfynbo@astro.ku.dk RI Nelemans, Gijs/D-3177-2012; Curran, Peter/B-5293-2013; Fynbo, Johan/L-8496-2014; Hjorth, Jens/M-5787-2014; Watson, Darach/E-4521-2015; Jensen, Brian Lindgren/E-1275-2015; Jakobsson, Pall/L-9950-2015; OI Nelemans, Gijs/0000-0002-0752-2974; Curran, Peter/0000-0003-3003-4626; Fynbo, Johan/0000-0002-8149-8298; Hjorth, Jens/0000-0002-4571-2306; Watson, Darach/0000-0002-4465-8264; Jensen, Brian Lindgren/0000-0002-0906-9771; Jakobsson, Pall/0000-0002-9404-5650; Wijers, Ralph/0000-0002-3101-1808; Sollerman, Jesper/0000-0003-1546-6615; Thone, Christina/0000-0002-7978-7648 NR 36 TC 134 Z9 135 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 JUN PY 2006 VL 451 IS 3 BP L47 EP L50 DI 10.1051/0004-6361:20065056 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 039TC UT WOS:000237329000007 ER PT J AU Grindrod, PM Hoogenboom, T AF Grindrod, Peter M. Hoogenboom, Trudi TI Venus: The corona conundrum SO ASTRONOMY & GEOPHYSICS LA English DT Article ID GLOBAL DISTRIBUTION; IMPACT CRATER; EVOLUTION; SUBDUCTION; TECTONICS; SURFACE; EARTH; MODEL; RELAXATION; MORPHOLOGY AB Coronae are large circular features on Venus, whose complex structure, with traces of tectonic and volcanic activity, mean that their origin remains enigmatic. Their non-random distribution, complex geological histories and associated volcanic features have been explained most successfully by models involving mantle upwelling. In this paper we summarize the models of their formation to date, paying particular attention to the success, as well as shortcomings, of these mantle upwetting models. We also describe recent models and theories that have highlighted the need for further investigation into the origin of coronae, with the aim of better understanding the evolution of the interior and surface of Venus. C1 UCL, Dept Earth Sci, London WC1E 6BT, England. Jet Prop Lab, Pasadena, CA 91106 USA. RP Grindrod, PM (reprint author), UCL, Dept Earth Sci, Gower St, London WC1E 6BT, England. EM p.grindrod@ucl.ac.uk RI Grindrod, Peter/F-5819-2011 OI Grindrod, Peter/0000-0002-0934-5131 NR 59 TC 4 Z9 4 U1 0 U2 1 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1366-8781 J9 ASTRON GEOPHYS JI Astron. Geophys. PD JUN PY 2006 VL 47 IS 3 BP 16 EP 21 PG 6 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA 054QD UT WOS:000238392800031 ER PT J AU Jaffe, TR Banday, AJ Eriksen, HK Gorski, KM Hansen, FK AF Jaffe, T. R. Banday, A. J. Eriksen, H. K. Gorski, K. M. Hansen, F. K. TI Fast and efficient template fitting of deterministic anisotropic cosmological models applied to WMAP data SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations ID PROBE 1ST-YEAR DATA; POWER-SPECTRUM; SKY MAPS; MICROWAVE; EMISSION; FOREGROUNDS; ROTATION; FREQUENCIES; ISOTROPY; SHEAR AB We explore methods of fitting templates to cosmic microwave background (CMB) data, and in particular demonstrate the application of the total convolver algorithm as a fast method of performing a search over all possible locations and orientations of the template relative to the sky. This analysis includes investigation of issues such as chance alignments and foreground residuals. We apply these methods to compare Bianchi models of type VIIh to WMAP first-year data and confirm the basic result of our 2005 paper. C1 Max Planck Inst Astrophys, D-85741 Garching, Germany. 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. Univ Warsaw Observ, PL-00478 Warsaw, Poland. RP Jaffe, TR (reprint author), Max Planck Inst Astrophys, Karl Schwarzschild Str 1,Postfach 1317, D-85741 Garching, Germany. EM tjaffe@mpa-garching.mpg.de; banday@mpa-garching.mpg.de; h.k.k.eriksen@astro.uio.no; krzysztof.m.gorski@jpl.nasa.gov; f.k.hansen@astro.uio.no NR 35 TC 29 Z9 29 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 JUN 1 PY 2006 VL 643 IS 2 BP 616 EP 629 DI 10.1086/501343 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XF UT WOS:000238338700003 ER PT J AU Donahue, M Horner, DJ Cavagnolo, KW Voit, GM AF Donahue, M Horner, DJ Cavagnolo, KW Voit, GM TI Entropy profiles in the cores of cooling flow clusters of galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE catalogs; cosmology : observations; galaxies : clusters : general; methods : data analysis; X-rays : galaxies : clusters ID X-RAY SPECTROSCOPY; XMM-NEWTON OBSERVATIONS; INTRACLUSTER MEDIUM; CHANDRA OBSERVATIONS; MOLECULAR-HYDROGEN; LUMINOUS CLUSTERS; ELEMENTAL ABUNDANCES; TEMPERATURE RELATION; HIGH-RESOLUTION; RADIO GALAXIES AB The X-ray properties of a relaxed cluster of galaxies are determined primarily by its gravitational potential well and the entropy distribution of its intracluster gas. That entropy distribution reflects both the accretion history of the cluster and the feedback processes that limit the condensation of intracluster gas. Here we present Chandra observations of the core entropy profiles of nine classic "cooling flow'' clusters that appear relatively relaxed ( at least outside the central 10 - 20 kpc) and contain intracluster gas with a cooling time less than a Hubble time. We show that those entropy profiles are remarkably similar, despite the fact that the clusters range over a factor of 3 in temperature. They typically have an entropy level of approximate to 130 keV cm(2) at 100 kpc that declines to a plateau similar to 10 keV cm(2) at less than or similar to 10 kpc. Between these radii, the entropy profiles are proportional to r(alpha) with alpha approximate to 1.0-1.3. The nonzero central entropy levels in these clusters correspond to a cooling time similar to 10(8) yr, suggesting that episodic heating on this timescale maintains the central entropy profile in a quasi - steady state. We show in an appendix that although disturbances and bubbles are visible in the central regions of these clusters, these phenomena do not strongly bias our entropy estimates. C1 Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Donahue, M (reprint author), Michigan State Univ, Dept Phys & Astron, BPS Bldg, E Lansing, MI 48824 USA. EM donahue@pa.msu.edu; horner@milkyway.gsfc.nasa.gov; cavagnolo@pa.msu.edu; voit@pa.msu.edu RI Donahue, Megan/B-5361-2012; OI Voit, Gerard/0000-0002-3514-0383 NR 86 TC 78 Z9 79 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 JUN 1 PY 2006 VL 643 IS 2 BP 730 EP 750 DI 10.1086/503270 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XF UT WOS:000238338700014 ER PT J AU Shaposhnikov, N Titarchuk, L AF Shaposhnikov, N Titarchuk, L TI Comprehensive analysis of RXTE data from Cygnus X-1: Spectral index-quasi-periodic oscillation frequency-luminosity correlations SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; radiation mechanisms : nonthermal; stars : individual (Cygnus X-1) ID X-RAY BINARIES; ACTIVE GALACTIC NUCLEI; MONTE-CARLO SIMULATIONS; LONG-TERM VARIABILITY; BLACK-HOLE CANDIDATES; NEUTRON-STAR BINARIES; ALPHA EMISSION-LINE; BROAD-BAND SPECTRUM; ACCRETION DISKS; POWER-LAW AB We present timing and spectral analysis of similar to 2.3 Ms of Rossi X-Ray Timing Explorer (RXTE) archival data from Cyg X-1. Using a generic Comptonization model we reveal that the spectrum of Cyg X-1 consists of three components: a thermal seed photon spectrum, a Comptonized part of the seed photon spectrum, and the iron line. We find a strong correlation between the 0.1-20 Hz frequencies of quasi-periodic oscillations (QPOs) and the spectral index. The presence of two spectral phases (states) is clearly seen in the data when the spectral indices saturate at low and high values of QPO frequencies. This saturation effect was discovered earlier in a number of black hole candidate (BHC) sources, and now we strongly confirm this phenomenon in Cyg X-1. In the soft state this index - QPO frequency correlation shows a saturation of the photon index Gamma similar to 2.1 at high values of the low frequency nu(L). The saturation level of Gamma similar to 2.1 is the lowest value found yet in BHCs. The bolometric luminosity does not show clear correlation with the index. We also show that Fe K alpha emission line strength (equivalent width [EW]) correlates with the QPO frequency. The EW increases from 200 eV in the low/hard state to 1.5 keV in the high/soft state. The observational correlations revealed compel us to propose a scenario for the spectral transition and iron line formation that occur in BHC sources. We also present the spectral state (power-law index) evolution for 8 yr of Cyg X-1 observations by RXTE. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Explorat Universe Div, Greenbelt, MD 20771 USA. George Mason Univ, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. USN, Res Lab, Washington, DC 20375 USA. RP Shaposhnikov, N (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Explorat Universe Div, Code 662, Greenbelt, MD 20771 USA. EM nikolai@milkyway.gsfc.nasa.gov; lev@milkyway.gsfc.nasa.gov NR 65 TC 45 Z9 45 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 JUN 1 PY 2006 VL 643 IS 2 BP 1098 EP 1113 DI 10.1086/503272 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XF UT WOS:000238338700041 ER PT J AU Pavlov, GG Sanwal, D Zavlin, VE AF Pavlov, GG Sanwal, D Zavlin, VE TI The pulsar wind nebula of the Geminga pulsar SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : individual (Geminga); stars : neutron; stars : winds, outflows ID X-RAY; CRAB-NEBULA; ORIGIN AB The superb spatial resolution of Chandra has allowed us to detect a 20 '' long tail behind the Geminga pulsar, with a hard spectrum (photon index Gamma = 1.0 +/- 0.2) and a luminosity of (1.3 +/- 0.2) x 10(29) ergs s(-1) in the 0.5-8 keV band, for an assumed distance of 200 pc. The tail could be either a pulsar jet, confined by a toroidal magnetic field of similar to 100 mu G, or it could be associated with the shocked relativistic wind behind the supersonically moving pulsar confined by the ram pressure of the oncoming interstellar medium. We also detected an arclike structure 5 ''-7 '' ahead of the pulsar, extended perpendicular to the tail, with a factor of 3 lower luminosity. We see a 3 sigma enhancement in the Chandra image apparently connecting the arc with the southern outer tail that has been possibly detected with XMM-Newton. The observed structures imply that the Geminga's pulsar wind is intrinsically anisotropic. C1 Penn State Univ, Davey Lab 525, University Pk, PA 16802 USA. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35805 USA. RP Pavlov, GG (reprint author), Penn State Univ, Davey Lab 525, University Pk, PA 16802 USA. EM pavlov@astro.psu.edu NR 18 TC 27 Z9 27 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 JUN 1 PY 2006 VL 643 IS 2 BP 1146 EP 1150 DI 10.1086/503250 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XF UT WOS:000238338700045 ER PT J AU Schmahl, EJ Kundu, MR Garaimov, VI AF Schmahl, EJ Kundu, MR Garaimov, VI TI Radio and hard X-ray imaging observations of the M5.7 flare of 2002 March 14 SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona; Sun : flares; Sun : radio radiation; Sun : X-rays, gamma rays ID INTERACTING CORONAL LOOPS; SOLAR-FLARE; MICROWAVE; CONFIGURATION; EMISSION; SPECTRA; YOHKOH; REGION; RHESSI; ELECTRONS AB We describe a flare of GOES class M5.7 that was observed simultaneously by RHESSI (Ramaty High Energy Solar Spectroscopic Imager) and NoRH (Nobeyama Radio Heliograph). The flare occurred in AR 9866 located near the disk center. The hard X-ray (HXR), microwave, EIT, and TRACE 195 angstrom observations indicate that the flaring region consisted of a complex of multiple loops. In the microwave domain the source morphology, the timing, the polarization characteristics, and the photospheric magnetic fields clearly indicate that it is of a class characterized as a "double loop'' configuration, meaning two systems of magnetic flux, each consisting of many smaller loops. The observations suggest the existence of a small loop system created by the emergence of new flux, which interacts with an old flux system, and of a remote flare site that is observed primarily in radio. The former is the main flare site where we observe microwave, HXR, and EUV emissions. In HXR there are two main identifiable loop systems. The first is an elongated one filled with energetic electrons primarily emitting lower energy ( 12 - 25 keV) HXR with a colocated microwave source; this source has distinct footpoints at higher X-ray energies. The second loop system is implied by compact HXR sources in opposite magnetic polarities separated by a distance greater than the length of the first loop system. Spectroscopic analysis of the RHESSI data shows that the spectrum can be fitted with a thick-target model with a thermal component and a broken power-law component of the electron energy distribution. This model is used to address the thermal/nonthermal and radio/HXR electron number problems. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Schmahl, EJ (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NR 28 TC 3 Z9 3 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 JUN 1 PY 2006 VL 643 IS 2 BP 1271 EP 1285 DI 10.1086/503151 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XF UT WOS:000238338700057 ER PT J AU Molnar, SM Birkinshaw, M Mushotzky, RF AF Molnar, SM Birkinshaw, M Mushotzky, RF TI Determining distances to clusters of galaxies using resonant X-ray emission lines SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmological parameters; cosmology : theory; X-rays : galaxies : clusters ID COSMOLOGICAL PARAMETERS; PERSEUS CLUSTER; XMM-NEWTON; DARK ENERGY; CONSTRAINTS; SCATTERING; EVOLUTION; CORE; GAS; OMEGA(LAMBDA) AB Bright clusters of galaxies can be seen out to cosmological distances, and thus they can be used to derive cosmological parameters. Although the continuum X-ray emission from the intracluster gas is optically thin, the optical depth of resonant lines of ions of heavy elements can be larger than unity. In this Letter, we study the feasibility of deriving distances to clusters of galaxies by determining the spatial distribution of the intracluster gas from X-ray imaging and the optical depth from resonant emission lines ( the XREL method). We solve the radiative transfer problem for line scattering in the hot intracluster gas using Monte Carlo simulations. We discuss the spatial and spectral resolutions needed to use the XREL method for accurate determination of distances, and hence cosmological parameters, and show that accurate distances will be obtained by applying this technique with the next generation of high-resolution X-ray spectrometers. C1 Univ Zurich, Inst Theoret Phys, CH-8057 Zurich, Switzerland. Univ Bristol, Dept Phys & Astron, Bristol BS8 1TL, Avon, England. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Molnar, SM (reprint author), Univ Zurich, Inst Theoret Phys, 190 Winterthurerstr, CH-8057 Zurich, Switzerland. NR 38 TC 3 Z9 3 U1 0 U2 2 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 JUN 1 PY 2006 VL 643 IS 2 BP L73 EP L76 DI 10.1086/505301 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053XI UT WOS:000238339000001 ER PT J AU Tylka, AJ Cohen, CMS Dietrich, WF Lee, MA MacLennan, CG Mewaldt, RA Ng, CK Reames, DV AF Tylka, A. J. Cohen, C. M. S. Dietrich, W. F. Lee, M. A. MacLennan, C. G. Mewaldt, R. A. Ng, C. K. Reames, D. V. TI A comparative study of ion characteristics in the large gradual solar energetic particle events of 2002 April 21 and 2002 August 24 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE acceleration of particles; shock waves; Sun : coronal mass ejections (CMEs); Sun : flares; Sun : particle emission ID CORONAL MASS EJECTIONS; ADVANCED COMPOSITION EXPLORER; DIFFUSIVE SHOCK ACCELERATION; DRIVEN SHOCKS; WIND SPACECRAFT; ISOTOPE SPECTROMETER; NEAR-EARTH; ABUNDANCES; TRANSPORT; INJECTION AB Solar energetic particles (SEPs) provide an opportunity to study in detail the processes of particle acceleration and transport that are ubiquitous in astrophysical plasmas. Tylka et al. focused on the problem of SEP spectral and compositional variability at energies above a few tens of MeV per nucleon. They motivated their study with two large, gradual SEP events, 2002 April 21 and 2002 August 24, which have similar fast coronal mass ejections (CMEs) and flares but nevertheless illustrate the extremes of high-energy behavior. In this paper, we present additional detailed comparisons between the ion characteristics of these events. These results should be helpful in developing and testing new SEP models, which are currently under development. C1 USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. CALTECH, Pasadena, CA 91125 USA. Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Tylka, AJ (reprint author), USN, Res Lab, EO Hulburt Ctr Space Res, Code 7652, Washington, DC 20375 USA. EM allan.tylka@nrl.navy.mil; cohen@srl.caltech.edu; dietrich@odysseus.uchicago.edu; marty.lee@unh.edu; cgm@bell-labs.com; rmewaldt@srl.caltech.edu; cheeng@lheapop.gsfc.nasa.gov; reames@milkyway.gsfc.nasa.gov RI Tylka, Allan/G-9592-2014 NR 70 TC 30 Z9 30 U1 2 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUN PY 2006 VL 164 IS 2 BP 536 EP 551 DI 10.1086/503203 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 053NT UT WOS:000238312500008 ER PT J AU Oltmans, SJ Lefohn, AS Harris, JM Galbally, I Scheel, HE Bodeker, G Brunke, E Claude, H Tarasick, D Johnson, BJ Simmonds, P Shadwick, D Anlauf, K Hayden, K Schmidlin, F Fujimoto, T Akagi, K Meyer, C Nichol, S Davies, J Redondas, A Cuevas, E AF Oltmans, S. J. Lefohn, A. S. Harris, J. M. Galbally, I. Scheel, H. E. Bodeker, G. Brunke, E. Claude, H. Tarasick, D. Johnson, B. J. Simmonds, P. Shadwick, D. Anlauf, K. Hayden, K. Schmidlin, F. Fujimoto, T. Akagi, K. Meyer, C. Nichol, S. Davies, J. Redondas, A. Cuevas, E. TI Long-term changes in tropospheric ozone SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE trends; surface ozone; ozonesondes; tropospheric chemistry; ozone transport ID SURFACE OZONE; VERTICAL-DISTRIBUTION; NITROGEN-DIOXIDE; GLOBAL NETWORK; ATLANTIC-OCEAN; TRENDS; TRANSPORT; CLIMATOLOGY; SWITZERLAND; SENSITIVITY AB Tropospheric ozone changes are investigated using a selected network of surface and ozonesonde sites to give a broad geographic picture of long-term variations. The picture of long-term tropospheric ozone changes is a varied one in terms of both the sign and magnitude of trends and in the possible causes for the changes. At mid latitudes of the S.H. three time series of similar to 20 years in length agree in showing increases that are strongest in the austral spring (August-October). Profile measurements show this increase extending through the mid troposphere but not into the highest levels of the troposphere. In the N.H. in the Arctic a period of declining ozone in the troposphere through the 1980s into the mid-1990s has reversed and the overall change is small. The decadal-scale variations in the troposphere in this region are related in part to changes in the lowermost stratosphere. At mid latitudes in the N.H., continental Europe and Japan showed significant increases in the 1970s and 1980s. Over North America rises in the 1970s are less than those seen in Europe and Japan, suggesting significant regional differences. In all three of these mid latitude, continental regions tropospheric ozone amounts appear to have leveled off or in some cases declined in the more recent decades. Over the North Atlantic three widely separated sites show significant increases since the late-1990s that may have peaked in recent years. In the N.H. tropics both the surface record and the ozonesondes in Hawaii show a significant increase in the autumn months in the most recent decade compared to earlier periods that drives the overall increase seen in the 30-year record. This appears to be related to a shift in the transport pattern during this season with more frequent flow from higher latitudes in the latest decade. (c) 2006 Elsevier Ltd. All rights reserved. C1 NOAA, Earth Syst Res Lab, Global Monitoring Div, Boulder, CO 80305 USA. ASL & Associates, Helena, MT 59601 USA. STC Corp, Boulder, CO 80303 USA. CSIRO Atmospher Res, Aspendale, Vic, Australia. Forschungszentrum Karlsruhe, IMK IFU, Garmisch Partenkirchen, Germany. S African Weather Serv, Stellenbosch, South Africa. Environm Canada, Meteorol Serv Canada, Toronto, ON, Canada. Univ Bristol, Sch Chem, Bristol, Avon, England. NASA, Goddard Space Flight Ctr, Wallops Isl, VA 23337 USA. Japan Meteorol Agcy, Tokyo, Japan. NIWA, Wellington, New Zealand. Observ Atmosfer Izana, INM, Santa Cruz de Tenerife, Spain. RP Oltmans, SJ (reprint author), NOAA, Earth Syst Res Lab, Global Monitoring Div, 325 Broadway, Boulder, CO 80305 USA. EM samuel.j.oltmans@noaa.gov RI Galbally, Ian/E-5852-2011; Meyer, Carl/H-2311-2011; Bodeker, Greg/A-8870-2008; Garmisch-Pa, Ifu/H-9902-2014; Redondas, Alberto/L-9299-2015; Cuevas, Emilio/L-2109-2013 OI Galbally, Ian/0000-0003-2383-1360; Meyer, Carl/0000-0002-8062-3712; Bodeker, Greg/0000-0003-1094-5852; Tarasick, David/0000-0001-9869-0692; Redondas, Alberto/0000-0002-4826-6823; Cuevas, Emilio/0000-0003-1843-8302 NR 57 TC 197 Z9 204 U1 4 U2 43 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 JUN PY 2006 VL 40 IS 17 BP 3156 EP 3173 DI 10.1016/j.atmosenv.2006.01.029 PG 18 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 047UR UT WOS:000237904700012 ER PT J AU Anderson, BE Chen, G Blake, DR AF Anderson, BE Chen, G Blake, DR TI Hydrocarbon emissions from a modern commercial airliner SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE aircraft emission; hydrocarbon emission indices; turbine engine ID AIRCRAFT TURBINE-ENGINES; CHEMICAL-COMPOSITION; EXHAUST; INDEXES; OZONE; CO AB We report selected carbon species emission indices (EIs) for a Rolls Royce RB211-535-E4 turbofan engine that were acquired during the NASA EXperiment to Characterize Aircraft Volatile Aerosol and Trace-species Emissions (EXCAVATE). Conducted during winter 2002, the mission focused upon characterizing the exhaust constituents of the NASA Boeing 757 aircraft during ground-based operation. Carbon species concentrations were determined by chromatographic analyses of whole air samples collected 10m behind the engine exit plane as engine power was varied from ground idle to about 60% of maximum rated thrust. Ambient air samples were also collected and analyzed to facilitate correction of calculated EIs for background concentrations. Results are consistent with previous observations and indicate that, on a relative basis, turbine engines emit considerable amounts of light hydrocarbon species at idle, but significantly lesser amounts at higher engine powers. (c) 2005 Elsevier Ltd. All rights reserved. C1 NASA, Langley Res Ctr, Hampton, VA 23662 USA. Univ Calif Irvine, Irvine, CA USA. RP Anderson, BE (reprint author), NASA, Langley Res Ctr, Hampton, VA 23662 USA. EM Bruce.E.Anderson@nasa.gov NR 17 TC 43 Z9 43 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD JUN PY 2006 VL 40 IS 19 BP 3601 EP 3612 DI 10.1016/j.atmosenv.2005.09.072 PG 12 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 056EP UT WOS:000238504400016 ER PT J AU Jacobson, NS Curry, DM AF Jacobson, NS Curry, DM TI Oxidation microstructure studies of reinforced carbon/carbon SO CARBON LA English DT Article DE carbon/carbon composites; oxidation; coating; reactivity; graphitic carbon ID CARBON-CARBON COMPOSITES; BEHAVIOR AB Laboratory oxidation studies of reinforced carbon/carbon (RCC) are discussed with particular emphasis on the resulting microstructures. This study involves laboratory furnace (500-1500 degrees C) and arc-jct exposures (1538 degrees C) on various forms of RCC. RCC without oxidation protection oxidized at 800 and 1100 degrees C exhibits pointed and reduced diameter fibers, due to preferential attack along the fiber edges. The 800 degrees C sample showed uniform attack, suggesting reaction control of the oxidation process; whereas the 1100 degrees C sample showed attack at the edges, suggesting diffusion control of the oxidation process. RCC with a SiC conversion coating exhibits limited attack of the carbon substrate at 500, 700 and 1500 degrees C. However samples oxidized at 900, 1100, and 1300 degrees C show small oxidation cavities at the SiC/carbon interface below through-thickness cracks in the SiC coating. These cavities at the outer edges suggest diffusion control. The cavities have rough edges with denuded fibers and can be easily distinguished from cavities created in processing. Arc-jet tests at 1538 degrees C show limited oxidation attack when the SiC coating and glass sealants are intact. When the SiC/sealant protection system is damaged, attack is extensive and proceeds through cracks, creating denuded fibers in and along the cracks. Even at 1538 degrees C, where diffusion control dominates, attack is non-uniform with fiber edges oxidizing preferentially. (c) 2005 Elsevier Ltd. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Jacobson, NS (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM nathan.s.jacobson@nasa.gov RI Jacobson, Nathan/A-9411-2009 NR 16 TC 157 Z9 172 U1 4 U2 33 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0008-6223 J9 CARBON JI Carbon PD JUN PY 2006 VL 44 IS 7 BP 1142 EP 1150 DI 10.1016/j.carbon.2005.11.013 PG 9 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 031FF UT WOS:000236689000004 ER PT J AU Michelini, M Franceschini, V Chen, SS Papini, S Rosellini, A Ciani, F Margolis, L Revoltella, RP AF Michelini, M Franceschini, V Chen, SS Papini, S Rosellini, A Ciani, F Margolis, L Revoltella, RP TI Primate embryonic stem cells create their own niche while differentiating in three-dimensional culture systems SO CELL PROLIFERATION LA English DT Article ID EXTRACELLULAR-MATRIX; ADHESION; FIBRONECTIN; BINDING; EMBRYOGENESIS; COMPLEXES; CADHERINS AB Rhesus monkey embryonic stem cells (ESCs) (R366.4), cultured on a three-dimensional (3D) collagen matrix with or without human neonatal foreskin fibroblasts (HP1.1) as feeder cells, or embedded in the collagen matrix, formed complex tubular or spherical gland-like structures and differentiated into phenotypes characteristic of neural, epithelial and endothelial lineages. Here, we analysed the production of endogenous extracellular matrix (ECM) proteins, cell-cell adhesion molecules, cell-surface receptors, lectins and their glycoligands, by differentiating ESCs, forming a micro-environment, a niche, able to positively influence cell behaviour. The expression of some of these molecules was modulated by HP1.1 cells while others were unaffected. We hypothesized that both soluble factors and the niche itself were critical in directing growth and/or differentiation of ESCs in this 3D environment. Creating such an appropriate experimental 3D micro-environment, further modified by ESCs and modulated by exogenous soluble factors, may constitute a template for adequate culture systems in developmental biology studies concerning differentiation of stem cells. C1 CNR, Inst Biomed Technol, I-56100 Pisa, Italy. Univ Bologna, Dept Evolut & Expt Biol, I-40126 Bologna, Italy. NICHD, NASA, NIH, Ctr 3 Dimens Tissue Culture, Bethesda, MD 20892 USA. NICHHD, Lab Cellular & Mol Biophys, NIH, Bethesda, MD 20892 USA. RP Revoltella, RP (reprint author), CNR, Inst Biomed Technol, Via G Moruzzi 1, I-56100 Pisa, Italy. EM r.revoltella@imd.pi.cnr.it NR 45 TC 17 Z9 18 U1 0 U2 3 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0960-7722 J9 CELL PROLIFERAT JI Cell Prolif. PD JUN PY 2006 VL 39 IS 3 BP 217 EP 229 DI 10.1111/j.1365-2184.2006.00381.x PG 13 WC Cell Biology SC Cell Biology GA 037XA UT WOS:000237179900005 PM 16671999 ER PT J AU Lau, KM Kim, MK Kim, KM AF Lau, KM Kim, MK Kim, KM TI Asian summer monsoon anomalies induced by aerosol direct forcing: the role of the Tibetan Plateau SO CLIMATE DYNAMICS LA English DT Article ID SCHUBERT SCHEME MCRAS; BLACK CARBON; PART I; CLIMATE; CLOUDS; SEA; MICROPHYSICS; VARIABILITY; ATMOSPHERE; CONTRAST AB In this paper we present results of a numerical study using the NASA finite-volume GCM to elucidate a plausible mechanism for aerosol impact on the Asian summer monsoon involving interaction with physical processes over the Tibetan Plateau (TP). During the pre-monsoon season of March-April, dusts from the deserts of western China, Afghanistan/Pakistan, and the Middle East are transported into and stacked up against the northern and southern slopes of the TP. The absorption of solar radiation by dust heats up the elevated surface air over the slopes. On the southern slopes, the atmospheric heating is reinforced by black carbon from local emission. The heated air rises via dry convection, creating a positive temperature anomaly in the mid-to-upper troposphere over the TP relative to the region to the south. In May through early June in a manner akin to an "elevated heat pump", the rising hot air forced by the increasing heating in the upper troposphere, draws in warm and moist air over the Indian subcontinent, setting the stage for the onset of the South Asia summer monsoon. Our results suggest that increased dust loading coupled with black carbon emission from local sources in northern India during late spring may lead to an advance of the rainy periods and subsequently an intensification of the Indian summer monsoon. The enhanced rainfall over India is associated with the development of an aerosol-induced large-scale sea level pressure anomaly pattern, which causes the East Asia (Mei-yu) rain belt to shift northwestward, suppressing rainfall over East Asia and the adjacent oceanic regions. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Kongju Natl Univ, Dept Atmospher Sci, Gongju, South Korea. Sci Syst & Applicat Inc, Lanham, MD USA. RP Lau, KM (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. EM lau@climate.gsfc.nasa.gov RI Kim, Kyu-Myong/G-5398-2014; Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 29 TC 424 Z9 452 U1 19 U2 119 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0930-7575 J9 CLIM DYNAM JI Clim. Dyn. PD JUN PY 2006 VL 26 IS 7-8 BP 855 EP 864 DI 10.1007/s00382-006-0114-z PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 036QK UT WOS:000237089600012 ER PT J AU Wang, YQ Zhang, CJ Zhou, E Sun, CJ Hinkley, J Gates, TS Su, J AF Wang, YQ Zhang, CJ Zhou, E Sun, CJ Hinkley, J Gates, TS Su, J TI Atomistic finite elements applicable to solid polymers SO COMPUTATIONAL MATERIALS SCIENCE LA English DT Article DE nano-simulation; molecular mechanics; atomistic element; finite element; polymer ID AMORPHOUS POLYMER; MECHANICAL-PROPERTIES; DEFORMATION; STRESS; STRAIN; MODEL AB A three-dimensional atomistic finite element approach is presented. Two types of elements are established: chemical bond and van der Waals bond. The stiffness matrices of these elements are established based upon relations between bond deformations and,restoration forces or moments. Once element stiffness matrices are established, a procedure, similar to conventional finite element analysis, can be employed to assemble a global stiffness matrix. Thus, one can derive relations between atomistic displacement and force. The new approach can be employed for both static and dynamic analysis. In order to demonstrate the approach, the deformation of an idealized polymer field is simulated: the stress-strain curve is derived and the progressive development of damage and failure is observed step by step. (c) 2005 Elsevier B.V. All rights reserved. C1 Kansas State Univ, Dept Mech & Nucl Engn, Manhattan, KS 66506 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Wang, YQ (reprint author), Kansas State Univ, Dept Mech & Nucl Engn, Manhattan, KS 66506 USA. EM wang@mne.ksu.edu NR 10 TC 16 Z9 16 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0256 J9 COMP MATER SCI JI Comput. Mater. Sci. PD JUN PY 2006 VL 36 IS 3 BP 292 EP 302 DI 10.1016/j.commatsci.2005.03.016 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA 045AX UT WOS:000237716100005 ER PT J AU Holzmann, GJ AF Holzmann, GJ TI The power of 10: Rules for developing safety-critical code SO COMPUTER LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Holzmann, GJ (reprint author), NASA, Jet Prop Labs, Lab Reliable Software, Pasadena, CA 91109 USA. EM gholzmann@acm.org NR 0 TC 18 Z9 18 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0018-9162 J9 COMPUTER JI Computer PD JUN PY 2006 VL 39 IS 6 BP 95 EP 97 PG 3 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering SC Computer Science GA 051VN UT WOS:000238189900026 ER PT J AU Shoemaker, WC Bayard, DS Wo, CCJ Botnen, A Chan, LS Chien, LC Lu, K Demetriades, D Belzberg, H Jelliffe, RW AF Shoemaker, WC Bayard, DS Wo, CCJ Botnen, A Chan, LS Chien, LC Lu, K Demetriades, D Belzberg, H Jelliffe, RW TI Stochastic model for outcome prediction in acute illness SO COMPUTERS IN BIOLOGY AND MEDICINE LA English DT Article DE stochastic (probability) analysis and control program; outcome prediction; noninvasive hemodynamic monitoring; thoracic bioimpedance cardiac output; tissue perfusion ID CRITICALLY ILL PATIENTS; RISK SURGICAL PATIENTS; OXYGEN DELIVERY; EMERGENCY PATIENTS; TRIAL; VALUES; OPTIMIZATION; CONSUMPTION; MORTALITY; TRAUMA AB The aims were to apply a stochastic model to predict outcome early in acute emergencies and to evaluate the effectiveness of various therapies in a consecutively monitored series of severely injured patients with noninvasive hemodynamic monitoring. The survival probabilities were calculated beginning shortly after admission to the emergency department (ED) and at subsequent intervals during their hospitalization. Cardiac function was evaluated by cardiac output (0), heart rate (HR), and mean arterial blood pressure (MAP), pulmonary function by pulse oximetry (SapO(2)), and tissue perfusion function by transcutaneous oxygen indexed to FiO(2), (PtCO2/FiO(2)), and carbon dioxide (PtcCO(2)) tension. The survival probability (SP) of survivors averaged 81.5 +/- 1.1% (SEM) and for nonsurvivors 57.7 +/- 2.3% (p < 0.001) in the first 24-hour period of resuscitation and subsequent management. The Cl, SapO(2), PtCO2/FiO(2) and MAP were significantly higher in survivors than in nonsurvivors during the initial resuscitation, while HR and PtcCO(2) tensions were higher in the nonsurvivors. Predictions made during the initial resuscitation period in the first 24-hours after admission were compared with the actual outcome at hospital discharge, which were usually several weeks later; misclassifications were 9.6% (16/167). The therapeutic decision support system objectively evaluated the responses of alternative therapies based on responses of patients with similar clinical-hemodynamic states. (c) 2005 Elsevier Ltd. All rights reserved. C1 Univ So Calif, Kech Sch Med, Dept Surg, LAC, Los Angeles, CA 90089 USA. Univ So Calif, Kech Sch Med, Dept Surg, USC Med Ctr, Los Angeles, CA USA. Univ So Calif, Keck Sch Med, Lab Appl Pharmacokinet, LAC, Los Angeles, CA USA. Univ So Calif, Keck Sch Med, Lab Appl Pharmacokinet, USC Med Ctr, Los Angeles, CA USA. Jet Propuls Lab, Pasadena, CA USA. RP Shoemaker, WC (reprint author), Univ So Calif, Kech Sch Med, Dept Surg, LAC, Los Angeles, CA 90089 USA. EM wcshoemaker00@hotmail.com FU NCRR NIH HHS [RR-11526]; NIGMS NIH HHS [GM-65619] NR 32 TC 2 Z9 2 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0010-4825 J9 COMPUT BIOL MED JI Comput. Biol. Med. PD JUN PY 2006 VL 36 IS 6 BP 585 EP 600 DI 10.1016/j.compbiomed.2005.03.006 PG 16 WC Biology; Computer Science, Interdisciplinary Applications; Engineering, Biomedical; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Computer Science; Engineering; Mathematical & Computational Biology GA 047LY UT WOS:000237882000003 PM 15979603 ER PT J AU Leshin, LA Vicenzi, E AF Leshin, Laurie A. Vicenzi, Edward TI Aqueous processes recorded by Martian meteorites: Analyzing Martian water on Earth SO ELEMENTS LA English DT Article DE Mars; meteorites; stable isotopes; carbonates; water-rock interaction ID SNC METEORITES; ISOTOPIC COMPOSITION; MARS; ALH84001; LAFAYETTE; HYDROGEN; CARBONATE; NAKHLA; ATMOSPHERE; EVOLUTION AB Martian meteorites have delivered to Earth water molecules and minerals produced by aqueous processes on Mars. The study of these samples, using powerful analytical instrumentation, provides a basis for understanding aqueous activity on Mars. Although most analyses are at the scale of microns, the conclusions reached have important implications for large-scale aqueous processes. Secondary minerals, such as clays, salts, and carbonates, are present at some level in all Martian meteorite subtypes and are especially important in the nakhlites and ALH84001. Light element stable isotope analyses show evidence for mixing between atmosphere and magmatic fluids into a crustal reservoir, and that this crustal water was not in equilibrium with the host rocks. The mineralogical and isotopic data present a fairly consistent picture of the aqueous history of Mars: low levels of aqueous alteration are generally present but extensive aqueous processes are probably limited in space and time. C1 NASA, Goddard Space Flight Ctr, Sci & Explorat Directorate, Greenbelt, MD 20771 USA. Smithsonian Inst, Museum Natl Hist Nat, Dept Mineral Sci, Washington, DC 20560 USA. RP Leshin, LA (reprint author), NASA, Goddard Space Flight Ctr, Sci & Explorat Directorate, Greenbelt, MD 20771 USA. EM laurie.leshin@nasa.gov; vicenzi@volcano.si.edu NR 34 TC 21 Z9 21 U1 1 U2 13 PU MINERALOGICAL SOC AMER PI CHANTILLY PA 3635 CONCORDE PKWY STE 500, CHANTILLY, VA 20151-1125 USA SN 1811-5209 EI 1811-5217 J9 ELEMENTS JI Elements PD JUN PY 2006 VL 2 IS 3 BP 157 EP 162 DI 10.2113/gselements.2.3.157 PG 6 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 052OW UT WOS:000238244000009 ER PT J AU Dick, SJ AF Dick, Steven J. TI NASA and the search for life in the universe SO ENDEAVOUR LA English DT Review ID EXOBIOLOGY AB Almost from its beginnings in 1958, the National Aeronautics and Space Administration (NASA) set up a life-science program. Because one of the priorities of the organization is to search for life beyond Earth, NASA began designing spacecraft to unravel the mysteries of Mars. The effort to search for life on Mars culminated in the landing of two Viking spacecraft on the surface of the planet in 1976. Although the biology experiments conducted as part of these missions provided some evidence for the possibility of life, the scientific consensus was that they drew a blank. In 1996, however, the 'Mars rock' rekindled interest in life in our solar system. The discovery of an ocean on the Jovian moon Europa, of organic molecules on the Saturnian moon Titan and persuasive evidence that water once flowed on Mars suggests that the solar system is still of considerable exobiological interest. In addition, since 1995 approximately 175 planets have been found beyond our solar system. Although these discoveries are gas giants, NASA spacecraft might soon detect Earth-sized planets. The search for life in the universe continues. C1 NASA HQ, Washington, DC 20546 USA. RP Dick, SJ (reprint author), NASA HQ, 300 E St SW, Washington, DC 20546 USA. EM Steven.J.Dick@nasa.gov NR 38 TC 9 Z9 10 U1 3 U2 16 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0160-9327 J9 ENDEAVOUR JI Endeavour PD JUN PY 2006 VL 30 IS 2 BP 71 EP 75 DI 10.1016/j.endeavour.2006.02.005 PG 5 WC History & Philosophy Of Science; Multidisciplinary Sciences SC History & Philosophy of Science; Science & Technology - Other Topics GA 063DK UT WOS:000238996100008 PM 16581126 ER PT J AU Dentener, F Stevenson, D Ellingsen, K van Noije, T Schultz, M Amann, M Atherton, C Bell, N Bergmann, D Bey, I Bouwman, L Butler, T Cofala, J Collins, B Drevet, J Doherty, R Eickhout, B Eskes, H Fiore, A Gauss, M Hauglustaine, D Horowitz, L Isaksen, ISA Josse, B Lawrence, M Krol, M Lamarque, JF Montanaro, V Muller, JF Peuch, VH Pitari, G Pyle, J Rast, S Rodriguez, J Sanderson, M Savage, NH Shindell, D Strahan, S Szopa, S Sudo, K Van Dingenen, R Wild, O Zeng, G AF Dentener, F. Stevenson, D. Ellingsen, K. van Noije, T. Schultz, M. Amann, M. Atherton, C. Bell, N. Bergmann, D. Bey, I. Bouwman, L. Butler, T. Cofala, J. Collins, B. Drevet, J. Doherty, R. Eickhout, B. Eskes, H. Fiore, A. Gauss, M. Hauglustaine, D. Horowitz, L. Isaksen, I. S. A. Josse, B. Lawrence, M. Krol, M. Lamarque, J. F. Montanaro, V. Muller, J. F. Peuch, V. H. Pitari, G. Pyle, J. Rast, S. Rodriguez, J. Sanderson, M. Savage, N. H. Shindell, D. Strahan, S. Szopa, S. Sudo, K. Van Dingenen, R. Wild, O. Zeng, G. TI The global atmospheric environment for the next generation SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID NITROGEN DEPOSITION; TROPOSPHERIC OZONE; SURFACE OZONE; IMPACT; AFRICA AB Air quality, ecosystem exposure to nitrogen deposition, and climate change are intimately coupled problems: we assess changes in the global atmospheric environment between 2000 and 2030 using 26 state-of-the-art global atmospheric chemistry models and three different emissions scenarios. The first (CLE) scenario reflects implementation of current air quality legislation around the world, while the second (MFR) represents a more optimistic case in which all currently feasible technologies are applied to achieve maximum emission reductions. We contrast these scenarios with the more pessimistic IPCC SRES A2 scenario. Ensemble simulations for the year 2000 are consistent among models and show a reasonable agreement with surface ozone, wet deposition, and NO2 satellite observations. Large parts of the world are currently exposed to high ozone concentrations and high deposition of nitrogen to ecosystems. By 2030, global surface ozone is calculated to increase globally by 1.5 +/- 1.2 ppb (CLE) and 4.3 +/- 2.2 ppb (A2), using the ensemble mean model results and associated +/- 1 sigma standard deviations. Only the progressive MFR scenario will reduce ozone, by -2.3 +/- 1.1 ppb. Climate change is expected to modify surface ozone by -0.8 +/- 0.6 ppb, with larger decreases over sea than over land. Radiative forcing by ozone increases by 63 +/- 15 and 155 +/- 37 mW m(-2) for CLE and A2, respectively, and decreases by -45 +/- 15 mW m(-2) for MFR. We compute that at present 10.1% of the global natural terrestrial ecosystems are exposed to nitrogen deposition above a critical load of 1 g N m(-2) yr(-1). These percentages increase by 2030 to 15.8% (CLE), 10.5% (MFR), and 25% (A2). This study shows the importance of enforcing current worldwide air quality legislation and the major benefits of going further. Nonattainment of these air quality policy objectives, such as expressed by the SRES-A2 scenario, would further degrade the global atmospheric environment. C1 Commiss European Communities, Joint Res Ctr, Inst Environm & Sustainabil, I-21020 Ispra, Italy. Univ Edinburgh, Sch Geosci, Edinburgh EH8 9YL, Midlothian, Scotland. Univ Oslo, Dept Geosci, Oslo, Norway. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Netherlands Environm Assessment Agcy, RIVM, MNP, Bilthoven, Netherlands. Int Inst Appl Syst Anal, A-2361 Laxenburg, Austria. JAMSTEC, Frontier Res Ctr Global Change, Yokohama, Kanagawa, Japan. Swiss Fed Inst Technol, EPFL, CH-1015 Lausanne, Switzerland. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Goddard Earth Sci & Technol Ctr, Baltimore, MD USA. Belgian Inst Space Aeron, Brussels, Belgium. CEA, CNRS, Lab Sci Climat & Environm, F-91198 Gif Sur Yvette, France. Lawrence Livermore Natl Lab, Div Atmospher Sci, Livermore, CA USA. Meteo France, CNRM, GMGEC, CATS, Toulouse, France. Max Planck Inst Chem, D-55128 Mainz, Germany. NOAA, GFDL, Princeton, NJ USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO USA. Max Planck Inst Meteorol, Hamburg, Germany. Met Off, Exeter, Devon, England. Univ Cambridge, Ctr Atmospher Sci, Cambridge, England. Univ Aquila, Dipartimento Fis, I-67100 Laquila, Italy. Univ Miami, Coral Gables, FL 33124 USA. NASA, Goddard Space Flight Ctr, Baltimore, MD USA. RP Dentener, F (reprint author), Commiss European Communities, Joint Res Ctr, Inst Environm & Sustainabil, Via E Fermi 1, I-21020 Ispra, Italy. EM frank.dentener@jrc.it RI Horowitz, Larry/D-8048-2014; Lamarque, Jean-Francois/L-2313-2014; Unger, Nadine/M-9360-2015; Pitari, Giovanni/O-7458-2016; Schultz, Martin/I-9512-2012; Peuch, Vincent-Henri/A-7308-2008; Wild, Oliver/A-4909-2009; Collins, William/A-5895-2010; Szopa, Sophie/F-8984-2010; Krol, Maarten/B-3597-2010; Bergmann, Daniel/F-9801-2011; Butler, Tim/G-1139-2011; Stevenson, David/C-8089-2012; Shindell, Drew/D-4636-2012; Strahan, Susan/H-1965-2012; Magana, Felipe/B-6966-2013; Krol, Maarten/E-3414-2013 OI Horowitz, Larry/0000-0002-5886-3314; Lamarque, Jean-Francois/0000-0002-4225-5074; Pitari, Giovanni/0000-0001-7051-9578; Schultz, Martin/0000-0003-3455-774X; Savage, Nicholas/0000-0001-9391-5100; Bouwman, Lex/0000-0002-2045-1859; Wild, Oliver/0000-0002-6227-7035; Collins, William/0000-0002-7419-0850; Szopa, Sophie/0000-0002-8641-1737; Bergmann, Daniel/0000-0003-4357-6301; Stevenson, David/0000-0002-4745-5673; NR 21 TC 199 Z9 203 U1 12 U2 91 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD JUN 1 PY 2006 VL 40 IS 11 BP 3586 EP 3594 DI 10.1021/es0523845 PG 9 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 048AY UT WOS:000237921200029 PM 16786698 ER PT J AU Tzortziou, M Herman, JR Gallegos, CL Neale, PJ Subramaniam, A Harding, LW Ahmad, Z AF Tzortziou, M Herman, JR Gallegos, CL Neale, PJ Subramaniam, A Harding, LW Ahmad, Z TI Bio-optics of the Chesapeake Bay from measurements and radiative transfer closure SO ESTUARINE COASTAL AND SHELF SCIENCE LA English DT Article DE estuaries; coastal waters; backscattering; chlorophyll fluorescence; particulate absorption; remote sensing ID DISSOLVED ORGANIC-MATTER; INFRARED SPECTRAL REGION; LIGHT-ABSORPTION; COASTAL WATERS; CHLOROPHYLL-A; OCEAN COLOR; AQUATIC PARTICLES; ATLANTIC BIGHT; PHASE FUNCTION; PHYTOPLANKTON AB We combined detailed bio-optical measurements and radiative transfer modeling to perform an 'optical closure' experiment for an optically complex and biologically productive region of the Chesapeake Bay. We used this experiment to evaluate certain assumptions commonly used in bio-optical models, and to investigate which optical characteristics are most important to accurately model and interpret remote sensing ocean-color observations in these Case 2 waters. Direct measurements were made of the magnitude, variability, and spectral characteristics of backscattering and absorption that are critical for accurate parameterizations in satellite bio-optical algorithms and underwater radiative transfer simulations. We found that the ratio of backscattering to total scattering (i.e. the backscattering fraction, b(b)/b) varied considerably depending on particulate loading, distance from land, and mixing processes, and had an average value of 0.0128 at 530 nm. Incorporating information on the magnitude, variability, and spectral characteristics of particulate backscattering into the radiative transfer model, rather than using a volume scattering function commonly assumed for turbid waters, was critical to obtaining agreement between model calculations and measured radiometric quantities. In-situ measurements of absorption coefficients need to be corrected for systematic overestimation due to scattering errors, and this correction commonly employs the assumption that absorption by particulate matter at near-infrared wavelengths is zero. Direct measurements, however, showed that particulate matter in the Bay had small, but non-zero, absorption in the 700-730 nm wavelength region. Accounting for this residual particulate absorption when correcting in-situ measured absorption spectra for scattering errors was important in model simulations of water reflectance in the green wavelengths, where reflectance spectra in estuarine waters peak. Sun-induced chlorophyll fluorescence considerably affected the magnitude of water reflectance in the red wavelengths. Very good optical closure was obtained between independently measured water inherent optical properties and radiation fields, after applying the results from our detailed measurements to model bio-optical processes in these Case 2 waters. The good optical closure was consistent over the observed wide range of water optical characteristics. Average absolute percent differences between measured and model-estimated water-leaving radiances were 6.35% at 443 nm, 7.73% at 554 nm, and 6.86% at 670 nm, considerably smaller than those presented in the few studies of optical closure performed previously in near shore waters of similar optical complexity. These results show that bio-optical processes can be confidently modeled in complex estuarine waters, and underscore the importance of accurate formulations for backscattering, long-wavelength particulate absorption, and chlorophyll fluorescence. (c) 2006 Elsevier Ltd. All rights reserved. C1 Univ Maryland, Earth Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. Columbia Univ, Lamont Doherty Geol Observ, Palisades, NY 10964 USA. Univ Maryland, Horn Point Lab, Ctr Environm Sci, Cambridge, MD 21613 USA. Sci & Data Syst Inc, Silver Spring, MD 20906 USA. RP Tzortziou, M (reprint author), Univ Maryland, Earth Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. EM martz@code613-3.gsfc.nasa.gov RI Neale, Patrick/A-3683-2012; OI Subramaniam, Ajit/0000-0003-1316-5827; Gallegos, Charles/0000-0001-5112-0166; Herman, Jay/0000-0002-9146-1632 NR 49 TC 64 Z9 71 U1 1 U2 9 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0272-7714 J9 ESTUAR COAST SHELF S JI Estuar. Coast. Shelf Sci. PD JUN PY 2006 VL 68 IS 1-2 BP 348 EP 362 DI 10.1016/j.ecss.2006.02.016 PG 15 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 057OG UT WOS:000238604500032 ER PT J AU Dubovikov, MS Canuto, VM AF Dubovikov, M. S. Canuto, V. M. TI Complete Eulerian-mean tracer equation for coarse resolution OGCMs SO GEOPHYSICAL AND ASTROPHYSICAL FLUID DYNAMICS LA English DT Article DE diapycnal mesoscale fluxes; adiabatic approximation; diffusion tensor; dynamic mesoscale model ID OCEAN CIRCULATION MODELS; MESOSCALE EDDIES; PARAMETERIZATION; THERMOCLINE; TRANSPORTS; FLUXES; WAVES AB McDougall and McIntosh showed that the adiabatic mesoscale mixing is represented incompletely in the tracer Eulerian-averaged equation (EAE) of coarse resolution OGCMs. We show that completing EAE requires an adequate decomposition of the mesoscale tracer flux F-tau = (U'tau') over bar which is achieved by means of transforming mesoscale fields to isopycnal coordinates (IC) where mesoscale dynamics has the simplest form. The transformation results in splitting F-tau into two components (F-b) over tilde and (F-tau) over tilde; the former is determined by buoyancy mesoscale dynamics only and has a trivial kinematic dependence on the mean tracer field, the latter is determined by mesoscale tracer dynamics. Thus, the problem of modelling (parameterizing) F-tau in ZC is divided in two stages which can be termed kinematic and dynamic. The kinematic stage consists in adequate decomposing F-tau, and the result is expressed in terms of mesoscale fields. The dynamic stage consists in applying a specific dynamic mesoscale model to parameterize the components of F-tau. In this article, we show that some components of F-tau are missing in ZC-OGCMs tracer equation and that their contribution is of the same order of magnitude as the mesoscale contribution itself. We also show that F-tau has components across mean isopycnals and that their existence is consistent with the adiabatic approximation which requires vanishing all fluxes across isopycnal surfaces. As for practical results, we derive the complete equation for the large scale tracer in ZC-OGCMs and present the parameterization of the terms which have been missing thus far. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Ctr Climate Syst Res, New York, NY 10025 USA. Columbia Univ, Dept Appl Phys & Math, New York, NY 10027 USA. RP Dubovikov, MS (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM mdubovikov@giss.nasa.gov NR 22 TC 3 Z9 3 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0309-1929 J9 GEOPHYS ASTRO FLUID JI Geophys. Astrophys. Fluid Dyn. PD JUN PY 2006 VL 100 IS 3 BP 197 EP 214 DI 10.1080/03091920600799830 PG 18 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Mechanics SC Astronomy & Astrophysics; Geochemistry & Geophysics; Mechanics GA 083DM UT WOS:000240436100003 ER PT J AU Sato, T Okuno, J Hinderer, J MacMillan, DS Plag, HP Francis, O Falk, R Fukuda, Y AF Sato, T Okuno, J Hinderer, J MacMillan, DS Plag, HP Francis, O Falk, R Fukuda, Y TI A geophysical interpretation of the secular displacement and gravity rates observed at Ny-Alesund, Svalbard in the Arctic - effects of post-glacial rebound and present-day ice melting SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE geodetic observations; Ny-A lesund; post-glacial rebound; present-day ice melting; sea-level change ID GLACIAL-ISOSTATIC-ADJUSTMENT; SEA-LEVEL CHANGE; COMPUTING 3-DIMENSIONAL DEFORMATIONS; BASE-LINE INTERFEROMETRY; FREE-AIR GRAVITY; BARENTS SEA; LATE PLEISTOCENE; POLAR ICE; ABSOLUTE GRAVIMETERS; SPECTRAL FORMALISM AB We have analysed the Ny-Alesund very long baseline interferometry (VLBI) data over the period 1994 August to 2004 May, and we obtain secular displacement rates relative to a NNR-NUVEL-1A reference frame of 0.2 +/- 0.5 mm yr(-1), -1.7 +/- 0.5 mm yr(-1) and 4.8 +/- 1.1 mm yr-1 for the north, east and vertical directions, respectively. The corresponding global positioning system (GPS) station displacement rates relative to the same reference frame for the north, east, and vertical directions are 0.2 +/- 0.6 mm yr(-1), -2.3 +/- 0.6 mm yr(-1), and 6.4 +/- 1.5 mm yr(-1) at NYA1 and - -0.1 +/- 0.5 mm yr(-1), -1.6 +/- 0.5 mm yr(-1), and 6.9 +/- 0.9 mm yr(-1) at NALL, where these GPS rates were derived from the ITRF2000 velocity solution of Heflin. From the comparison at 25 globally distributed collocated sites, we found that the difference in uplift rate between VLBI and GPS at Ny-Alesund is mainly due to a GPS reference frame scale rate error corresponding to 1.6 mm yr-1 in the GPS vertical rates. The uplift rate was estimated to be 5.2 +/- 0.3 mm yr(-1) from the analysis of the tide gauge data at Ny-Alesund. Hence the uplift rates obtained from three different kinds of data are very consistent each other. The absolute gravity (AG) measurements at Ny-Alesund, which were carried out four times (period: 1998-2002) by three different FG5 absolute gravimeters, lead to a decreasing secular rate of -2.5 +/- 0.9 mu Gal yr(-1) (1 mu Gal = 10(-8) m s(-2)). In this analysis, the actual data obtained from a superconducting gravimeter at Ny-Alesund were used in the corrections for the gravity tide (including the ocean tide effect) and for the air pressure effect. We have estimated three geophysical contributions to examine the observed rates: (1) the effect of the sea-level (SL) change on a timescale of a few decades, (2) the effect of the present-day ice melting (PDIM) in Svalbard and (3) the sensitivity of the computed post-glacial rebound (PGR) effects to different choices of the models of past ice history and Earth's viscosity parameters. Our analysis indicates that the effect of SL change can be neglected as the main source of the discrepancy. On the other hand, the effect of PDIM cannot be ignored in explaining the mutual relation between the observed horizontal and vertical rates and the predicted ones. A large melting rate of the order of -75 cm yr(11) (i.e. roughly 1.6 times larger than the mean rate derived from glaciology over Svalbard) would explain the observed uplift but only half of the gravity changes. Our comparison results clearly point out the importance of both the estimation accuracy of the elastic deformations and better observation accuracy to constrain the size of PGR effects in the northwestern Svalbard more tightly. C1 Natl Astron Observ Japan, Mizusawa 0230861, Japan. Kyoto Univ, Sakyo Ku, Kyoto 6068224, Japan. ULP, CNRS, UMR 7516, Inst Phys Globe Strasbourg, F-67084 Strasbourg, France. NASA, Goddard Space Flight Ctr, NVI Inc, Greenbelt, MD 20771 USA. Norway Mapping Author, N-3511 Honefoss, Norway. European Ctr Geodynam & Seismol, L-7526 Luxembourg, Luxembourg. Bundesamt Kartog & Geodasie, D-60598 Frankfurt, Germany. RP Sato, T (reprint author), Natl Astron Observ Japan, 2-12 Hishigaoka, Mizusawa 0230861, Japan. EM tsato@miz.nao.ac.jp NR 77 TC 29 Z9 29 U1 2 U2 5 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0956-540X J9 GEOPHYS J INT JI Geophys. J. Int. PD JUN PY 2006 VL 165 IS 3 BP 729 EP 743 DI 10.1111/j.1365-246X.2006.02992.x PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 058ET UT WOS:000238649000003 ER PT J AU Smith, JG Connell, JW AF Smith, JG Connell, JW TI Microwave synthesis of phenylethynyl imide oligomers: Neat resin and composite properties of PETI-298 SO HIGH PERFORMANCE POLYMERS LA English DT Article DE resin transfer molding; high temperature polymers; polyimide synthesis; PETI-330 ID TEMPERATURE; RADIATION AB PETI-298 is a high temperature/high performance matrix resin that is processable into composites by resin transfer molding (RTM), resin infusion, and vacuum-assisted RTM techniques. It is prepared by the conventional amide acid approach in a polar aprotic solvent from the reaction of an aromatic anhydride and a combination of diamines and endcapped with phenylethynylphthalic anhydride. As a means to eliminate solvent and decrease reaction time in order to address final resin cost, the microwave synthesis of PETI-298 was investigated. The monomers were manually mixed and placed in a microwave oven for various times to determine optimum conditions. The resultant materials were characterized for thermal and rheological properties and compared with PETI-298 prepared by the classic amide acid approach. The synthetic process was subsequently scaled-up to 330 g. Three batches were prepared and combined to give similar to 1 kg of material that was subsequently used to fabricate flat laminates on T650 carbon fabric by RTM. The composite panels were analyzed and mechanical properties determined. These properties were compared with those fabricated from PETI-298 prepared by the classic amide acid approach. Based on solubility characteristics, melt viscosity and Fourier transform infrared spectroscopy, the phenylethynyl group did not react under the conditions investigated. This approach is applicable to the synthesis of a variety of phenylethynyl-terminated imide oligomers. C1 NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. Tulane Univ, Dept Chem, New Orleans, LA 70118 USA. M&P Technol Inc, Marietta, GA 30067 USA. RP Connell, JW (reprint author), NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. EM john.w.connell@nasa.gov NR 17 TC 7 Z9 7 U1 1 U2 10 PU SAGE PUBLICATIONS LTD PI LONDON PA 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND SN 0954-0083 J9 HIGH PERFORM POLYM JI High Perform. Polym. PD JUN PY 2006 VL 18 IS 3 BP 341 EP 354 DI 10.1177/0954008306062634 PG 14 WC Polymer Science SC Polymer Science GA 050TO UT WOS:000238111600008 ER PT J AU Klingelhofer, G Morris, RV De Souza, PA Rodionov, D Schroder, C AF Klingelhoefer, G. Morris, R. V. De Souza, P. A., Jr. Rodionov, D. Schroeder, C. TI Two earth years of Mossbauer studies of the surface of Mars with MIMOS II SO HYPERFINE INTERACTIONS LA English DT Article DE MIMOS II; weathering; Mars; jarosite; goethite; hematite; field distribution; Gusev crater; Meridiani Planum; Mars-exploration-rovers; mineralogy; instrumentation; backscattering ID X-RAY SPECTROMETER; MERIDIANI-PLANUM; MARTIAN SOIL; GUSEV CRATER; SPECTROSCOPY; ROCKS AB The element iron plays a crucial role in the study of the evolution of matter from an interstellar cloud to the formation and evolution of the planets. In the Solar System iron is the most abundant metallic element. It occurs in at least three different oxidation states: Fe(0) (metallic iron), Fe(II) and Fe(III). Fe(IV) and Fe(VI) compounds are well known on Earth, and there is a possibility for their occurrence on Mars. In January 2004 the USA space agency NASA landed two rovers on the surface of Mars, both carrying the Mainz Mossbauer spectrometer MIMOS II. They performed for the first time in-situ measurements of the mineralogy of the Martian surface, at two different places on Mars, Meridiani Planum and Gusev crater, respectively, the landing sites of the Mars-Exploration-Rovers (MER) Opportunity and Spirit. After about two Earth years or one Martian year of operation the Mossbauer (MB) spectrometers on both rovers have acquired data from more than 150 targets (and more than thousand MB spectra) at each landing site. The scientific measurement objectives of the Mossbauer investigation are to obtain for rock, soil, and dust (1) the mineralogical identification of iron-bearing phases (e.g., oxides, silicates, sulfides, sulfates, and carbonates), (2) the quantitative measurement of the distribution of iron among these iron-bearing phases (e.g., the relative proportions of iron in olivine, pyroxenes, ilmenite and magnetite in a basalt), (3) the quantitative measurement of the distribution of iron among its oxidation states (e.g., Fe2+, Fe3+, and Fe6+), and (4) the characterization of the size distribution of magnetic particles. Special geologic targets of the Mossbauer investigation are dust collected by the Athena magnets and interior rock and soil surfaces exposed by the Athena Rock Abrasion Tool and by trenching with rover wheels. The Mossbauer spectrometer on Opportunity at Meridiani Planum, identified eight Fe-bearing phases: jarosite (K,Na,H3O)(Fe,Al)(OH)6(SO4)2, hematite, olivine, pyroxene, magnetite, nanophase ferric oxides (npOx), an unassigned ferric phase, and a metallic Fe-Ni alloy (kamacite) in a Fe-Ni-meteorite. Outcrop rocks consist of hematite-rich spherules dispersed throughout S-rich rock that has nearly constant proportions of Fe3+ from jarosite, hematite, and npOx (28%, 35%, and 19% of total Fe). Jarosite is mineralogical evidence for aqueous processes under acid-sulfate conditions because it has structural hydroxide and sulfate and it forms at low pH. Hematite-rich spherules, eroded from the outcrop, and their fragments are concentrated as hematite-rich soils (lag deposits) on ripple crests (up to 68% of total Fe from hematite). Olivine, pyroxene, and magnetite are primarily associated with basaltic soils and are present as thin and locally discontinuous cover over outcrop rocks, commonly forming aeolian bedforms. Basaltic soils are more reduced (Fe3+/Fe-total similar to 0.2-0.4), with the fine-grained and bright aeolian deposits being the most oxidized. Basaltic soil at Meridiani Planum and Gusev crater have similar Fe-mineralogical compositions. At Gusev crater, the Mossbauer spectrometer on the MER Spirit rover has identified 8 Fe-bearing phases. Two are Fe2+ silicates (olivine and pyroxene), one is a Fe2+ oxide (ilmenite), one is a mixed Fe2+ and Fe3+ oxide (magnetite), two are Fe3+ oxides (hematite and goethite), one is a Fe3+ sulfate (mineralogically not constrained), and one is a Fe3+ alteration product (npOx). The surface material in the plains have a olivine basaltic signature (Morris, et al., Science, 305: 833, 2004; Morris, et al., J. Geophys. Res., 111, 2006, Ming, et al., J. Geophys. Res., 111, 2006) suggesting physical rather than chemical weathering processes present in the plains. The Mossbauer signature for the Columbia Hills surface material is very different ranging from nearly unaltered material to highly altered material. Some of the rocks, in particular a rock named Clovis, contain a significant amount of the Fe oxyhydroxide goethite, alpha-FeOOH, which is mineralogical evidence for aqueous processes because it is formed only under aqueous conditions. C1 Johannes Gutenberg Univ Mainz, Inst Inorgan & Analyt Chem, D-55099 Mainz, Germany. NASA Johnson Space Ctr, Houston, TX USA. CVRD, Rio De Janeiro, Brazil. RP Klingelhofer, G (reprint author), Johannes Gutenberg Univ Mainz, Inst Inorgan & Analyt Chem, Staudinger Weg 9, D-55099 Mainz, Germany. EM klingel@mail.uni-mainz.de RI de Souza, Paulo/B-8961-2008; Schroder, Christian/B-3870-2009 OI de Souza, Paulo/0000-0002-0091-8925; Schroder, Christian/0000-0002-7935-6039 NR 19 TC 10 Z9 10 U1 4 U2 16 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0304-3843 J9 HYPERFINE INTERACT JI Hyperfine Interact. PD JUN PY 2006 VL 170 IS 1-3 BP 169 EP 177 DI 10.1007/s10751-007-9508-5 PG 9 WC Physics, Atomic, Molecular & Chemical; Physics, Condensed Matter; Physics, Nuclear SC Physics GA 137RA UT WOS:000244308500018 ER PT J AU Fedorov, A Budnik, E Sauvaud, JA Mazelle, C Barabash, S Lundin, R Acuna, M Holmstrom, M Grigoriev, A Yamauchi, M Andersson, H Thocaven, JJ Winningham, D Frahm, R Sharber, JR Scherrer, J Coates, AJ Linder, DR Kataria, DO Kallio, E Koskinen, H Sales, T Riihela, P Schmidt, W Kozyra, J Luhmann, J Roelof, E Williams, D Livi, S Curtis, CC Hsieh, KC Sandel, BR Grande, M Carter, M McKenna-Lawler, S Orsini, S Cerulli-Irelli, R Maggi, M Wurz, P Bochsler, P Krupp, N Woch, J Franz, M Asamura, K Dierker, C AF Fedorov, A. Budnik, E. Sauvaud, J. -A. Mazelle, C. Barabash, S. Lundin, R. Acuna, M. Holmstrom, M. Grigoriev, A. Yamauchi, M. Andersson, H. Thocaven, J. -J. Winningham, D. Frahm, R. Sharber, J. R. Scherrer, J. Coates, A. J. Linder, D. R. Kataria, D. O. Kallio, E. Koskinen, H. Sales, T. Riihela, P. Schmidt, W. Kozyra, J. Luhmann, J. Roelof, E. Williams, D. Livi, S. Curtis, C. C. Hsieh, K. C. Sandel, B. R. Grande, M. Carter, M. McKenna-Lawler, S. Orsini, S. Cerulli-Irelli, R. Maggi, M. Wurz, P. Bochsler, P. Krupp, N. Woch, J. Fraenz, M. Asamura, K. Dierker, C. TI Structure of the martian wake SO ICARUS LA English DT Article DE Mars; magnetospheres ID SOLAR-WIND INTERACTION; PLASMA ENVIRONMENT; ION ESCAPE; MARS; MAGNETOTAIL; BOUNDARY; VENUS; MODEL; TAIL; MAGNETOSPHERE AB We present the first results from the ion mass analyzer IMA of the ASPERA-3 instrument on-board of Mars Express. More than 200 orbits for May 2004-September 2004 time interval have been selected for the statistical study of the distribution of the atmospheric origin ions in the planetary wake. This Study shows that the martian magnetotail consists of two different ion regimes. Planetary origin ions of the first regime form the layer adjacent to the magnetic pile-up boundary. These ions are accelerated to energy greater than 2000 eV and exhibit a gradual decreasing of energy down to the planetary tail. The second plasma regime is observed in the planetary shadow. The heavy ions (considered as planetary ones) are accelerated to the energy of the solar wind protons. Obviously the acceleration mechanism is different for the different plasma regimes. Study of two plasma regimes in the frame referred to the interplanetary magnetic field (IMF) direction (we used MGS magnetometer data to obtain the IMF clock angle) clearly shows their spatial anisotropy. The monoenergetic plasma in the planetary shadow is observed only in the narrow angular sector around the positive direction of the interplanetary electric field. (c) 2005 Elsevier Inc. All rights reserved. C1 Ctr Etud Spatiale Rayonnements, F-31028 Toulouse, France. Swedish Inst Space Phys, S-98128 Kiruna, Sweden. Goddard Space Flight Ctr, Greenbelt, MD USA. SW Res Inst, San Antonio, TX 78220 USA. Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. Univ Michigan, Space Phys Res Lab, Ann Arbor, MI 48109 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Univ Arizona, Tucson, AZ 85721 USA. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Natl Univ Ireland, Space Technol Ltd, Maynooth, Kildare, Ireland. Ist Fis Spazio Interplanetario, I-00133 Rome, Italy. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Inst Space & Astronaut Sci, Sagamihara, Kanagawa, Japan. Tech Univ Braunschweig, D-38106 Braunschweig, Germany. Univ Bern, Inst Phys, CH-3012 Bern, Switzerland. RP Fedorov, A (reprint author), Ctr Etud Spatiale Rayonnements, BP-4346, F-31028 Toulouse, France. EM andrei.feclorov@cesr.fr RI Koskinen, Hannu/B-4971-2017; Coates, Andrew/C-2396-2008; Grande, Manuel/C-2242-2013; Kallio, Esa/F-9410-2014 OI Koskinen, Hannu/0000-0003-3839-6461; Coates, Andrew/0000-0002-6185-3125; Grande, Manuel/0000-0002-2233-2618; Kallio, Esa/0000-0002-9791-804X FU Science and Technology Facilities Council [PP/D000831/1] NR 26 TC 54 Z9 55 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 JUN PY 2006 VL 182 IS 2 BP 329 EP 336 DI 10.1016/j.icarus.2005.09.021 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 052JE UT WOS:000238229200004 ER PT J AU Futaana, Y Barabash, S Grigoriev, A Holmstrom, M Kallio, E Brandt, PC Gunell, H Brinkfeldt, K Lundin, R Andersson, H Yamauchi, M McKenna-Lawler, S Winningham, JD Frahm, RA Sharber, JR Scherrer, JR Coates, AJ Linder, DR Kataria, DO Sales, T Riihela, P Schmidt, W Koskinen, H Kozyra, J Luhmann, J Roelof, E Williams, D Livi, S Curtis, CC Hsieh, KC Sandel, BR Grande, M Carter, M Sauvaud, JA Fedorov, A Thocaven, JJ Orsini, S Cerulli-Irelli, R Maggi, M Wurz, P Bochsler, P Krupp, N Woch, J Franz, M Asamura, K Dierker, C AF Futaana, Y. Barabash, S. Grigoriev, A. Holmstrom, M. Kallio, E. C son Brandt, P. Gunell, H. Brinkfeldt, K. Lundin, R. Andersson, H. Yamauchi, M. McKenna-Lawler, S. Winningham, J. D. Frahm, R. A. Sharber, J. R. Scherrer, J. R. Coates, A. J. Linder, D. R. Kataria, D. O. Sales, T. Riihela, P. Schmidt, W. Koskinen, H. Kozyra, J. Luhmann, J. Roelof, E. Williams, D. Livi, S. Curtis, C. C. Hsieh, K. C. Sandel, B. R. Grande, M. Carter, M. Sauvaud, J. -A. Fedorov, A. Thocaven, J. -J. Orsini, S. Cerulli-Irelli, R. Maggi, M. Wurz, P. Bochsler, P. Krupp, N. Woch, J. Fraenz, M. Asamura, K. Dierker, C. TI First ENA observations at Mars: Subsolar ENA jet SO ICARUS LA English DT Article DE Mars, atmosphere; solar wind; magnetospheres ID ENERGETIC NEUTRAL ATOMS; SOLAR-WIND INTERACTION; MAGNETIC-FIELD; GLOBAL SURVEYOR; IMAGE MISSION; ATMOSPHERE; SIMULATION AB The Neutral Particle Detector (NPD), an Energetic Neutral Atom (ENA) sensor of the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) on board Mars Express, detected intense fluxes of ENAs emitted from the subsolar region of Mars. The typical ENA fluxes are (4-7) x 10(5) cm(-2) sr(-1) s(-1) in the energy range 0.3-3 keV. These ENAs are likely to be generated in the subsolar region of the martian exosphere. As the satellite moved away from Mars, the ENA flux decreased while the field of view of the NPD pointed toward the subsolar region. These decreases occurred very quickly with a time scale of a few tens of seconds in two thirds of the orbits. Such a behavior can be explained by the spacecraft crossing a spatially constrained ENA jet, i.e., a highly directional ENA emission from a compact region of the subsolar exosphere. This ENA jet is highly possible to be emitted conically from the subsolar region. Such directional ENAs can result from the anisotropic solar wind flow around the subsolar region. but this can not be explained in the frame of MHD models. (c) 2005 Elsevier Inc. All rights reserved. C1 Swedish Inst Space Phys, SE-98128 Kiruna, Sweden. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Natl Univ Ireland, Space Technol Ireland, Maynooth, Kildare, Ireland. SW Res Inst, San Antonio, TX 78228 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Univ Helsinki, Dept Phys Sci, FIN-00014 Helsinki, Finland. Univ Michigan, Space Phys Res Lab, Ann Arbor, MI 48109 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Arizona, Tucson, AZ 85721 USA. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Ctr Etud Spatiale Rayonnements, F-31028 Toulouse, France. Ist Fis Spazio Interplanetario, I-00133 Rome, Italy. Univ Bern, Inst Phys, CH-3012 Bern, Switzerland. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Inst Space & Astronaut Sci, Sagamihara, Kanagawa, Japan. Tech Univ Braunschweig, D-38106 Braunschweig, Germany. RP Futaana, Y (reprint author), Swedish Inst Space Phys, Box 812, SE-98128 Kiruna, Sweden. EM futaana@irf.se RI Coates, Andrew/C-2396-2008; Gunell, Herbert/D-5611-2013; Futaana, Yoshifumi/P-5899-2014; Grande, Manuel/C-2242-2013; Kallio, Esa/F-9410-2014; Koskinen, Hannu/B-4971-2017; Brandt, Pontus/N-1218-2016; OI Coates, Andrew/0000-0002-6185-3125; Futaana, Yoshifumi/0000-0002-7056-3517; Grande, Manuel/0000-0002-2233-2618; Kallio, Esa/0000-0002-9791-804X; Koskinen, Hannu/0000-0003-3839-6461; Brandt, Pontus/0000-0002-4644-0306; Gunell, Herbert/0000-0001-5379-1158 FU Science and Technology Facilities Council [PP/D000831/1] NR 25 TC 27 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 JUN PY 2006 VL 182 IS 2 BP 413 EP 423 DI 10.1016/j.icarus.2005.08.024 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 052JE UT WOS:000238229200013 ER PT J AU Futaana, Y Barabash, S Grigoriev, A Holmstrom, M Kallio, E Brandt, PC Gunell, H Brinkfeldt, K Lundin, R Andersson, H Yamauchi, M McKenna-Lawler, S Winningham, JD Frahm, RA Sharber, JR Scherrer, JR Coates, AJ Linder, DR Kataria, DO Sales, T Riihela, P Schmidt, W Koskinen, H Kozyra, J Luhmann, J Roelof, E Williams, D Livi, S Curtis, CC Hsieh, KC Sandel, BR Grande, M Carter, M Sauvaud, JA Fedorov, A Thocaven, JJ Orsini, S Cerulli-Irelli, R Maggi, M Wurz, P Bochsler, P Galli, A Krupp, N Woch, J Franz, A Asamura, K Dierker, C AF Futaana, Y. Barabash, S. Grigoriev, A. Holmstrom, M. Kallio, E. C son Brandt, P. Gunell, H. Brinkfeldt, K. Lundin, R. Andersson, H. Yamauchi, M. McKenna-Lawler, S. Winningham, J. D. Frahm, R. A. Sharber, J. R. Scherrer, J. R. Coates, A. J. Linder, D. R. Kataria, D. O. Sales, T. Riihela, P. Schmidt, W. Koskinen, H. Kozyra, J. Luhmann, J. Roelof, E. Williams, D. Livi, S. Curtis, C. C. Hsieh, K. C. Sandel, B. R. Grande, M. Carter, M. Sauvaud, J. -A. Fedorov, A. Thocaven, J. -J. Orsini, S. Cerulli-Irelli, R. Maggi, M. Wurz, P. Bochsler, P. Galli, A. Krupp, N. Woch, J. Fraenz, A. Asamura, K. Dierker, C. TI First ENA observations at Mars: ENA emissions from the martian upper atmosphere SO ICARUS LA English DT Article DE Mars, atmosphere; solar wind; atmospheres, dynamics; atmospheres, structure; ionospheres ID ENERGETIC NEUTRAL ATOMS; SOLAR-WIND INTERACTION; GLOBAL SURVEYOR; HYDROGEN-ATOMS AB The neutral particle detector (NPD) on board Mars Express has observed energetic neutral atoms (ENAs) from a broad region on the dayside of the martian upper atmosphere. We show one such example for which the observation was conducted at an altitude of 570 km, just above the induced magnetosphere boundary (IMB). The time of flight spectra of these ENAs show that they had energies of 0.2-2 keV/amu, with an average energy of similar to 1.1 keV/amu. Both the spatial distribution and the energy of these ENAs are consistent with the backscattered ENAs, produced by an ENA albedo process. This is the first observation of backscattered ENAs from the martian upper atmosphere. The origin of these ENAs is considered to be the solar wind ENAs that are scattered back by collision processes in the martian upper atmosphere. The particle flux and energy flux of the backscattered ENAs are 0.9-1.3 x 10(7) cm(-2) s(-1) and similar to 9.5 x 10(9) eV cm(-2) s(-1), respectively. (c) 2005 Elsevier Inc. All rights reserved. C1 Swedish Inst Space Phys, SE-98128 Kiruna, Sweden. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Natl Univ Ireland, Space Technol Ireland, Maynooth, Kildare, Ireland. SW Res Inst, San Antonio, TX 78228 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Univ Helsinki, Dept Phys Sci, FIN-00014 Helsinki, Finland. Univ Michigan, Space Phys Res Lab, Ann Arbor, MI 48109 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Arizona, Tucson, AZ 85721 USA. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Ctr Etud Spatiale Rayonnements, F-31028 Toulouse, France. Ist Fis Spazio Interplanetario, I-00133 Rome, Italy. Univ Bern, Inst Phys, CH-1012 Bern, Switzerland. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Inst Space & Astronaut Sci, Sagamihara, Kanagawa, Japan. Tech Univ Braunschweig, D-38106 Braunschweig, Germany. RP Futaana, Y (reprint author), Swedish Inst Space Phys, Box 812, SE-98128 Kiruna, Sweden. EM futaana@irf.se RI Gunell, Herbert/D-5611-2013; Futaana, Yoshifumi/P-5899-2014; Grande, Manuel/C-2242-2013; Kallio, Esa/F-9410-2014; Koskinen, Hannu/B-4971-2017; Brandt, Pontus/N-1218-2016; Coates, Andrew/C-2396-2008 OI Futaana, Yoshifumi/0000-0002-7056-3517; Grande, Manuel/0000-0002-2233-2618; Kallio, Esa/0000-0002-9791-804X; Koskinen, Hannu/0000-0003-3839-6461; Brandt, Pontus/0000-0002-4644-0306; Gunell, Herbert/0000-0001-5379-1158; Coates, Andrew/0000-0002-6185-3125 FU Science and Technology Facilities Council [PP/D000831/1] NR 18 TC 25 Z9 25 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 JUN PY 2006 VL 182 IS 2 BP 424 EP 430 DI 10.1016/j.icarus.2005.09.019 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 052JE UT WOS:000238229200014 ER PT J AU Benner, LAM Nolan, MC Ostro, SJ Giorgini, JD Pray, DP Harris, AW Magri, C Margot, JL AF Benner, LAM Nolan, MC Ostro, SJ Giorgini, JD Pray, DP Harris, AW Magri, C Margot, JL TI Near-Earth Asteroid 2005 CR37: Radar images and photometry of a candidate contact binary SO ICARUS LA English DT Article DE asteroids; radar; surfaces, asteroids; asteroids, composition ID OPTICAL OBSERVATIONS; DOUBLET CRATERS; PHYSICAL MODEL; 433 EROS; EVOLUTION; TOUTATIS; SHAPE; ENCOUNTERS; INVERSION AB Arecibo (2380 MHz, 13 cm) radar observations of 2005 CR37 provide detailed images of a candidate contact binary: a 1.8-km-long, extremely bifurcated object. Although the asteroid's two lobes are round, there are regions of modest topographic relief, such as an elevated, 200-m-wide facet, that suggest that the lobes are geologically more complex than either coherent fragments or homogeneous rubble piles. Since January 1999, about 9% of NEAs larger than similar to 200 m imaged by radar can be described as candidate contact binaries. (c) 2006 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Astron & Ionosphere Ctr, Arecibo Observ, Arecibo, PR 00612 USA. Carbuncle Hill Observ, Coventry, RI 02816 USA. Space Sci Inst, La Canada Flintridge 91011, CA USA. Univ Maine, Farmington, ME 04938 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. RP Benner, LAM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM lance.benner@jpl.nasa.gov RI Margot, Jean-Luc/A-6154-2012; Nolan, Michael/H-4980-2012 OI Margot, Jean-Luc/0000-0001-9798-1797; Nolan, Michael/0000-0001-8316-0680 NR 52 TC 22 Z9 23 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 JUN PY 2006 VL 182 IS 2 BP 474 EP 481 DI 10.1016/j.icarus.2006.01.016 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 052JE UT WOS:000238229200019 ER PT J AU Emery, JP Cruikshank, DP Van Cleve, J AF Emery, J. P. Cruikshank, D. P. Van Cleve, J. TI Thermal emission spectroscopy (5.2-38 mu m) of three Trojan asteroids with the Spitzer Space Telescope: Detection of fine-grained silicates SO ICARUS LA English DT Review DE asteroids; asteroids, composition; infrared observations; spectroscopy; surfaces, asteroids ID TAGISH LAKE METEORITE; NEAR-EARTH ASTEROIDS; MAIN BELT ASTEROIDS; SPECTRAL IRRADIANCE CALIBRATION; INFRARED SPECTROGRAPH IRS; SOLAR-SYSTEM; MU-M; OPTICAL-CONSTANTS; REFLECTANCE SPECTRA; HALE-BOPP AB We present thermal emission spectra (5.2-38 mu m) of the Trojan asteroids 624 Hektor, 911 Agamemnon, and 1172 Aneas. The observations used the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope. Emissivity spectra are created by dividing the measured Spectral Energy Distribution (SED) by a model of the thermal continuum. We employ the Standard Thermal Model (STM), allowing physical parameters (e.g., radius and albedo) to vary in order to find the best thermal continuum fit to the SED. The best-fit effective radius (R) and visible geometric albedo (p(v)) for Hektor (R = 110.0 +/- 7.3, p(v) = 0.038(-0.017)(+0.028)) and Aneas (R = 69.1 +/- 5.1, p(v) = 0.044(-0.014)(+0.020)) agree very well with previous estimates, and for Agamemnon (R = 71.5 +/- 5.2, p(v) = 0.062(-0.019)(+0.024)) we find slightly a smaller size and higher albedo than previously derived. Other thermal models (e.g., thermophysical) result in estimates of R and pv that vary a few percent from the STM, but the resulting emissivity spectra are identical. The emissivity spectra of all three asteroids display an emissivity plateau near 10-mu m and another broader rise from similar to 18 to 28 mu m. We interpret these as indications of fine-grained silicates on the surfaces of these asteroids. The emissivity spectra more closely resemble emission spectra from cometary comae than those from solid surfaces and measured in the laboratory for powdered meteorites and regolith analogs. We hypothesize that the coma-like emission from the solid surfaces of trojans may be due to small silicate grains being imbedded in a relatively transparent matrix, or to a very under-dense (fairy-castle) surface structure. These hypotheses need to be tested by further laboratory and theoretical scattering work as well as continued thermal emission observations of asteroids. (c) 2006 Elsevier Inc. All rights reserved. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. Ball Aerosp & Technol Corp, Boulder, CO 80301 USA. RP Emery, JP (reprint author), NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. EM jemery@mail.arc.nasa.gov NR 113 TC 76 Z9 76 U1 0 U2 9 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD JUN PY 2006 VL 182 IS 2 BP 496 EP 512 DI 10.1016/j.icarus.2006.01.011 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 052JE UT WOS:000238229200022 ER PT J AU Yelle, RV Borggren, N de la Haye, V Kasprzak, WT Niemann, HB Muller-Wodarg, I Waite, JH AF Yelle, RV Borggren, N de la Haye, V Kasprzak, WT Niemann, HB Muller-Wodarg, I Waite, JH TI The vertical structure of Titan's upper atmosphere from Cassini Ion Neutral Mass Spectrometer measurements SO ICARUS LA English DT Article DE planets; aeronomy ID MOLECULAR-HYDROGEN; ESCAPE AB Data acquired by the Ion Neutral Mass Spectrometer (INMS) oil the Cassini spacecraft during its close encounter with Titan on 26 October 2004 reveal the structure of its upper atmosphere. Altitude profiles of N-2, CH4, and H-2, inferred from INMS measurements, determine the temperature, vertical mixing rate, and escape flux from the upper atmosphere. The mean atmospheric temperature in the region sampled by the INMS is 149 +/- 3 K, where the variance is a consequence of local time variations in temperature. The CH4 mole fraction at 1174 km is 2.7 +/- 0.1%. The effects of diffusive separation are clearly seen in the data that we interpret as all eddy diffusion coefficient of 4(-3)(+4) x 10(9) cm(2) s(-1), that, along with the measured CH4 mole fraction, implies a mole fraction in the stratosphere of 2.2 +/- 0.2%. The H-2 distribution is affected primarily by upward flow and atmospheric escape. The H-2 mole fraction at 1200 km is 4 +/- 1 x 10(-3) and analysis of the altitude profile indicates all upward flux of 1.2 +/- 0.2 x 10(10) cm(-2) s(-1), referred to the surface. If horizontal variations in temperature and H-2 density are small, this upward flux also represents the escape flux from the atmosphere. The CH4 density exhibits significant horizontal variations that are likely in indication of dynamical processes in the upper atmosphere. (c) 2005 Elsevier Inc. All rights reserved. C1 Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. Univ Michigan, Dept Atmospher Ocean Sci & Space Phys, Ann Arbor, MI 48109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ London Imperial Coll Sci & Technol, Space & Atmospher Phys Grp, London SW7 2BW, England. RP Yelle, RV (reprint author), Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. EM yelle@lpl.arizona.edu RI Mueller-Wodarg, Ingo/M-9945-2014 OI Mueller-Wodarg, Ingo/0000-0001-6308-7826 NR 22 TC 73 Z9 74 U1 1 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 JUN PY 2006 VL 182 IS 2 BP 567 EP 576 DI 10.1016/j.icarus.2005.10.029 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 052JE UT WOS:000238229200027 ER PT J AU Cornford, SL Feather, MS Hicks, KA AF Cornford, Steven L. Feather, Martin S. Hicks, Kenneth A. TI DDP: A tool for life-cycle risk management SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB At JPL we have developed and implemented a process for achieving fife-cycle risk management. This process has been embodied in a software tool and is called Defect Detection and Prevention (DDP). The DDP process can be succinctly stated as: determine where we want to be, what could get in the way and how we will get there. The "determine where we want to be" is captured as trees of requirements and the "what could get in the way" is captured as trees of potential failure modes'. Scoring the impacts of these failure modes on the requirements results in a prioritized set of failure modes. The user then selects from a set of Preventative measures, Analyses, process Controls and Tests (PACTS) each of which has an effectiveness versus the various failure modes. It is the goal of the DDP process to optimally select the subset of the PACTs(2) which minimizes the residual risk subject to the project resource constraints. The DDP process is intended to facilitate risk management over the entire project fife cycle beginning with architectural and advanced technology decisions all the way through operation. As the project design, technology content, and implementation approach matures, the requirements and failure mode trees are elaborated upon to accommodate the additional information. Thus, the DDP process is a systematic, continuous, top-down approach to managing risk. Implementation of the DDP process requires a critical mass of expertise (usually the project team and a few specialists) and captures both their engineering judgement as wen as available quantitative data. This additional data may result from models, layouts, prototype testing, other focused risk evaluations and institutional experiences. The DDP process also identifies areas where additional information would be advantageous, thus allowing a project to target critical areas of risk or risk uncertainty. This also allows the project to identify those areas which would benefit the most from application of other quantitative tools and methods (e.g. Monte Carlo simulations, FMECAs, fault trees). The software tool supports the DDP process by providing guidance for implementing the process steps, graphical visualizations of the various trees, their interrelationships and the current risk landscape. The tool is capable of supporting on-the-fly knowledge elicitation as well as integrating off-line deliberations. There are a variety of available outputs including graphs, trees and reports as well as clear identification of the driving requirements, "tall-pole"' residual risks and the PACTS which have been selected and agreed upon. The DDP process has been applied at various levels of assembly including the system and subsystem levels, as well as down to the component level. Recently, significant benefits have been realized from application to advanced technologies, where the focus has been on increasing the infusion rates of these technologies by identification and mitigation of risks prior to delivery to a project. C1 CALTECH, Jet Prop Lab, Strateg Syst Technol Program Off, Pasadena, CA 91109 USA. RP Cornford, SL (reprint author), CALTECH, Jet Prop Lab, Strateg Syst Technol Program Off, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 3 Z9 3 U1 1 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0885-8985 J9 IEEE AERO EL SYS MAG JI IEEE Aerosp. Electron. Syst. Mag. PD JUN PY 2006 VL 21 IS 6 BP 13 EP 22 DI 10.1109/MAES.2006.1662004 PN 1 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA 061LS UT WOS:000238874500003 ER PT J AU Kirby, PL Pukala, D Manohara, H Mehdi, I Papapolymerou, J AF Kirby, PL Pukala, D Manohara, H Mehdi, I Papapolymerou, J TI Characterization of micromachined silicon rectangular waveguide at 400 GHz SO IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS LA English DT Article DE laser micromachining; micromachining; silicon waveguide; submillimeter; terahertz (THz) AB We present the first characterization of a micromachined silicon rectangular waveguide at 400 GHz. The silicon waveguide has an average loss of 0.086 dB/mm for a range of 350-460 GHz. The waveguides are formed using well known microfabrication techniques and demonstrate a successful first step towards the use of silicon waveguides as a viable option for THz systems. C1 Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kirby, PL (reprint author), Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA. EM pkirby@ieee.org NR 8 TC 24 Z9 25 U1 1 U2 6 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 JUN PY 2006 VL 16 IS 6 BP 366 EP 368 DI 10.1109/LMWC.2006.875593 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 050EI UT WOS:000238069900016 ER PT J AU Trebi-Ollennu, A AF Trebi-Ollennu, A TI Great adventures on the surface of Mars SO IEEE ROBOTICS & AUTOMATION MAGAZINE LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91125 USA. RP Trebi-Ollennu, A (reprint author), CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91125 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1070-9932 J9 IEEE ROBOT AUTOM MAG JI IEEE Robot. Autom. Mag. PD JUN PY 2006 VL 13 IS 2 BP 6 EP + DI 10.1109/MRA.2006.1638006 PG 2 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA 050DV UT WOS:000238068600004 ER PT J AU Erickson, JK AF Erickson, JK TI Living the dream - An overview of the Mars Exploration Project SO IEEE ROBOTICS & AUTOMATION MAGAZINE LA English DT Article DE rover; MER; Mars Exploration Rover ID OPERATIONS; MISSION C1 CALTECH, Jet Prop Lab, Mars Explorat Rover Project, Pasadena, CA 91109 USA. RP Erickson, JK (reprint author), CALTECH, Jet Prop Lab, Mars Explorat Rover Project, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM James.K.Erickson@jpl.nasa.gov NR 10 TC 19 Z9 19 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1070-9932 J9 IEEE ROBOT AUTOM MAG JI IEEE Robot. Autom. Mag. PD JUN PY 2006 VL 13 IS 2 BP 12 EP 18 DI 10.1109/MRA.2006.1638011 PG 7 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA 050DV UT WOS:000238068600006 ER PT J AU Lindemann, RA Bickler, DB Harrington, BD Ortiz, GM Voorhees, CJ AF Lindemann, RA Bickler, DB Harrington, BD Ortiz, GM Voorhees, CJ TI Mars Exploration Rover mobility development - Mechanical mobility hardware design, development, and testing SO IEEE ROBOTICS & AUTOMATION MAGAZINE LA English DT Article DE Mars; Mars Exploration Rover; MER; mobility; rocker-bogie suspension; planetary rover C1 CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. CALTECH, Jet Prop Lab, NASA, Mars Sci Lab, Pasadena, CA 91109 USA. RP Lindemann, RA (reprint author), CALTECH, Jet Prop Lab, NASA, M-S 158-230 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Randel.A.Lindemann@jpl.nasa.gov NR 15 TC 27 Z9 33 U1 0 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1070-9932 J9 IEEE ROBOT AUTOM MAG JI IEEE Robot. Autom. Mag. PD JUN PY 2006 VL 13 IS 2 BP 19 EP 26 DI 10.1109/MRA.2006.1638012 PG 8 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA 050DV UT WOS:000238068600007 ER PT J AU Baumgartner, ET Bonitz, RG Melko, JP Shiraishi, LR Leger, PC Trebi-Ollennu, A AF Baumgartner, Eric T. Bonitz, Robert G. Melko, Joseph P. Shiraishi, Lori R. Leger, P. Christopher Trebi-Ollennu, Ashitey TI Mobile manipulation for the Mars Exploration Rover - A dexterous and robust instrument positioning system SO IEEE ROBOTICS & AUTOMATION MAGAZINE LA English DT Article DE manipulators; planetary robotics; mobile manipulation; Mars exploration C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Baumgartner, ET (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Eric.T.Baumgartner@jpl.nasa.gov NR 12 TC 9 Z9 9 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1070-9932 EI 1558-223X J9 IEEE ROBOT AUTOM MAG JI IEEE Robot. Autom. Mag. PD JUN PY 2006 VL 13 IS 2 BP 27 EP 36 DI 10.1109/MRA.2006.1638013 PG 10 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA 050DV UT WOS:000238068600008 ER PT J AU Wright, J Hartman, F Cooper, B Maxwell, S Yen, J Morrison, J AF Wright, J Hartman, F Cooper, B Maxwell, S Yen, J Morrison, J TI Driving on Mars with RSVP - Building safe and effective command sequences SO IEEE ROBOTICS & AUTOMATION MAGAZINE LA English DT Article DE Mars; rovers; autonomy; commanding; ground operations; telepresence C1 CALTECH, Jet Prop Lab, Rover Sequencing & Visualizat Program, Pasadena, CA USA. RP Wright, J (reprint author), CALTECH, Jet Prop Lab, Rover Sequencing & Visualizat Program, 4800 Oak Grove Dr, Pasadena, CA USA. EM John.R.Wright@jpl.nasa.gov NR 14 TC 9 Z9 9 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1070-9932 J9 IEEE ROBOT AUTOM MAG JI IEEE Robot. Autom. Mag. PD JUN PY 2006 VL 13 IS 2 BP 37 EP 45 DI 10.1109/MRA.2006.1638014 PG 9 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA 050DV UT WOS:000238068600009 ER PT J AU Mishkin, AH Limonadi, D Laubach, SL Bass, DS AF Mishkin, AH Limonadi, D Laubach, SL Bass, DS TI Working the Martian night shift - The MER surface operations process SO IEEE ROBOTICS & AUTOMATION MAGAZINE LA English DT Article DE space; Mars; mission operations; Mars Exploration Rover; MER; Spirit; Opportunity C1 CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. RP Mishkin, AH (reprint author), CALTECH, Jet Prop Lab, NASA, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Andrew.H.Mishkin@jpl.nasa.gov NR 7 TC 9 Z9 9 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1070-9932 J9 IEEE ROBOT AUTOM MAG JI IEEE Robot. Autom. Mag. PD JUN PY 2006 VL 13 IS 2 BP 46 EP 53 DI 10.1109/MRA.2006.1638015 PG 8 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA 050DV UT WOS:000238068600010 ER PT J AU Cheng, Y Maimone, MW Matthies, L AF Cheng, Y Maimone, MW Matthies, L TI Visual odometry on the Mars Exploration Rovers - A tool to ensure accurate driving and science imaging SO IEEE ROBOTICS & AUTOMATION MAGAZINE LA English DT Article DE MER; Mars Exploration Rover; visual odometry; motion estimation; egomotion C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Maimone, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM mark.mai-mone@jpl.nasa.gov NR 14 TC 68 Z9 74 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1070-9932 J9 IEEE ROBOT AUTOM MAG JI IEEE Robot. Autom. Mag. PD JUN PY 2006 VL 13 IS 2 BP 54 EP 62 DI 10.1109/MRA.2006.1638016 PG 9 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA 050DV UT WOS:000238068600011 ER PT J AU Biesiadecki, JJ Baumgartner, ET Bonitz, RG Cooper, BK Hartman, FR Leger, PC Maimone, MW Maxwell, SA Trebi-Ollennu, A Tunstel, EW Wright, JR AF Biesiadecki, JJ Baumgartner, ET Bonitz, RG Cooper, BK Hartman, FR Leger, PC Maimone, MW Maxwell, SA Trebi-Ollennu, A Tunstel, EW Wright, JR TI Mars Exploration Rover surface operations - Driving opportunity at Meridiani Planum SO IEEE ROBOTICS & AUTOMATION MAGAZINE LA English DT Article DE MER; Mars rover; Mars surface operations; robot mobility; robotics C1 CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. CALTECH, Jet Prop Lab, Robot Sequencing & Visualizat Program, Pasadena, CA 91109 USA. RP Biesiadecki, JJ (reprint author), CALTECH, Jet Prop Lab, NASA, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Jeffrey.J.Biesiadecki@jpl.nasa.gov NR 8 TC 14 Z9 14 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1070-9932 J9 IEEE ROBOT AUTOM MAG JI IEEE Robot. Autom. Mag. PD JUN PY 2006 VL 13 IS 2 BP 63 EP 71 DI 10.1109/MRA.2006.1638017 PG 9 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA 050DV UT WOS:000238068600012 ER PT J AU Naderi, F McCleese, DJ Jordan, JF AF Naderi, F McCleese, DJ Jordan, JF TI Mars exploration - What have we learned? What lies ahead? SO IEEE ROBOTICS & AUTOMATION MAGAZINE LA English DT Article DE Mars; rovers; life detection; search for water; entry; descent and landing C1 CALTECH, Jet Prop Lab, NASA, Mars Explorat Program, Pasadena, CA 91109 USA. CALTECH, Jet Prop Lab, Mars Explorat Directorate, Pre Projects & Adv Studies Off, Pasadena, CA 91109 USA. RP Naderi, F (reprint author), CALTECH, Jet Prop Lab, NASA, Mars Explorat Program, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM naderi@jpl.nasa.gov NR 0 TC 4 Z9 4 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1070-9932 J9 IEEE ROBOT AUTOM MAG JI IEEE Robot. Autom. Mag. PD JUN PY 2006 VL 13 IS 2 BP 72 EP 82 DI 10.1109/MRA.2006.1638018 PG 11 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA 050DV UT WOS:000238068600013 ER PT J AU Nikolaou, S Ponchak, GE Papapolymerou, J Tentzeris, MM AF Nikolaou, S Ponchak, GE Papapolymerou, J Tentzeris, MM TI Conformal double exponentially tapered slot antenna (DETSA) on LCP for UWB applications SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article DE conformal antenna; distortion; double exponentially slot antenna (DETSA); liquid crystal polymer (LCP); ultrawideband (UWB); ultrashort pulse AB We discuss the use of a double exponentially tapered slot antenna (DETSA) fabricated on flexible liquid crystal polymer (LCP) as a candidate for ultrawideband (UWB) communications systems. The features of the antenna and the effect of the antenna on a transmitted pulse are investigated. Return loss and E and H plane radiation pattern measurements are presented in several frequencies covering the whole ultra wide band. The return loss remains below -10 dB and the shape of the radiation pattern remains fairly constant in the whole UWB range (3.110.6 GHz). The main lobe characteristic of the radiation pattern remains stable even when the antenna is significantly conformed. The major effect of the conformation is an increase in the cross polarization component amplitude. The system: transmitter DETSA-channel-receiver DETSA is measured in frequency domain and shows that the antenna adds very little distortion on a transmitted pulse. The distortion remains small even when both transmitter and receiver antennas are folded, although it increases slightly. C1 Georgia Inst Technol, Atlanta, GA 30302 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Nikolaou, S (reprint author), Georgia Inst Technol, Atlanta, GA 30302 USA. EM simos@ece.gatech.edu NR 17 TC 47 Z9 47 U1 1 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD JUN PY 2006 VL 54 IS 6 BP 1663 EP 1669 DI 10.1109/TAP.2006.875915 PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 052KK UT WOS:000238232400006 ER PT J AU Conley, JE Chen, Y Knowlton, B Sullivan, T Tonti, B AF Conley, John E. Chen, Yuan Knowlton, Bill Sullivan, Tim Tonti, Bill TI Guest editorial - Introduction to the special issue on the 2005 International Integrated Reliability Workshop SO IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY LA English DT Editorial Material C1 Sharp Labs Amer, LCD Proc & Technol Dev Lab, Camas, WA 98607 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Boise State Univ, Boise, ID 83725 USA. IBM Microelect, Essex Jct, VT 05452 USA. RP Conley, JE (reprint author), Sharp Labs Amer, LCD Proc & Technol Dev Lab, Camas, WA 98607 USA. EM jconley@sharplabs.com; Yuan.Chen@jpl.nasa.gov; bknowlton@boisestate.edu; tdsulliv@us.ibm.com; wtonti@us.ibm.com NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1530-4388 J9 IEEE T DEVICE MAT RE JI IEEE Trans. Device Mater. Reliab. PD JUN PY 2006 VL 6 IS 2 BP 115 EP 116 DI 10.1109/TDMR.2006.877374 PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 078CB UT WOS:000240077700001 ER PT J AU Chen, Y Westergard, L Mojarradi, MM Johnson, TW Cozy, RS Billman, C Burke, GR Kolawa, EA AF Chen, Yuan Westergard, Lynett Mojarradi, Mohammad M. Johnson, Travis W. Cozy, Raymond Scott Billman, Curtis Burke, Gary R. Kolawa, Elizabeth A. TI Design for ASIC reliability for low-temperature applications SO IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY LA English DT Article; Proceedings Paper CT IEEE International Integrated Reliability Workshop CY OCT 17-20, 2005 CL S Lake Tahoe, CA SP IEEE Elect Devices Soc, IEEE Reliabil Soc DE circuit reliability; device reliability; hot carrier aging (HCA); low-temperature electronics ID HOT-CARRIER-RELIABILITY; CIRCUITS AB A design for reliability methodology has been developed for electronics for low-temperature applications. A hot carrier aging (HCA) lifetime projection model is proposed to take into account the HCA impact on technology, analysis of parametric degradation versus critical circuit path degradation, transistor bias profile, transistor substrate current profile, and operating temperature profile. The most applicable transistor size can, be determined in order to meet the reliability requirements of the electronics operating under low temperatures. This methodology and approach can also be applied to other transistor-level failure and/or degradation mechanisms for applications with varying temperature ranges. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. AMI Semicond, Pocatello, ID 83201 USA. RP Chen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM yuan.chen@jpl.nasa.gov NR 16 TC 5 Z9 6 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1530-4388 J9 IEEE T DEVICE MAT RE JI IEEE Trans. Device Mater. Reliab. PD JUN PY 2006 VL 6 IS 2 BP 146 EP 153 DI 10.1109/TDMR.2006.876590 PG 8 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 078CB UT WOS:000240077700006 ER PT J AU Cameron, CB Rodriguez, RN Padgett, N Waluschka, E Kizhner, S Colon, G Weeks, C AF Cameron, CB Rodriguez, RN Padgett, N Waluschka, E Kizhner, S Colon, G Weeks, C TI Fast optical ray tracing using multiple DSPs SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE digital signal processor (DSP); moderate resolution; imaging spectroradiometer (MODIS); optical ray tracing; optics; parallel processing; reconfigurable computing; resistance-capacitance (RC) AB Optical ray tracing is a computationally intensive operation that is central both to the design of optical systems and to analyzing their performance once built. The authors have previously reported on the use of parallel digital signal processors (DSPs) to reduce the time required to perform ray tracing in analyzing the performance of the moderate resolution imaging spectroradiometer (MODIS), which is presently in orbit on multiple spacecraft. The earlier work was incomplete, providing only a conservative estimate of the performance improvement that could be achieved with one to four DSPs. This paper reports on the completed project and extends the earlier work to eight DSPs. As predicted in the earlier paper, not all rays make it through the entire optical system. Many are lost along the way. This is one factor that led to reduced processing time. Another is the use of an optimizing compiler. In this paper, the authors present results showing the separate effect of each of these two independent factors on the overall processing time. The most significant finding is the extraordinarily linear relationship between the number of DSPs available and the speed of the ray tracing. By using eight DSPs, the processing time is reduced from two weeks to less than one and a half days, an improvement of nearly a whole order of magnitude. Low-cost high-speed ray tracing is now feasible using off-the-shelf plug-in processor boards. C1 USN Acad, Annapolis, MD 21402 USA. Univ Puerto Rico, Mayaguez, PR 00681 USA. Georgia Inst Technol, Atlanta, GA 30332 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20768 USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. RP Cameron, CB (reprint author), USN Acad, Annapolis, MD 21402 USA. EM cameronc@usna.edu NR 13 TC 3 Z9 3 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD JUN PY 2006 VL 55 IS 3 BP 801 EP 808 DI 10.1109/TIM.2006.873813 PG 8 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 046ZK UT WOS:000237849400016 ER PT J AU Trejo, LJ Rosipal, R Matthews, B AF Trejo, LJ Rosipal, R Matthews, B TI Brain-computer interfaces for 1-D and 2-D cursor control: Designs using volitional control of the EEG spectrum or steady-state visual evoked potentials SO IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING LA English DT Article; Proceedings Paper CT 3rd International Meeting on Brain-Computer Interface Technology CY JUN, 2005 CL Rensselaerville Inst, Rensselaerville, NY HO Rensselaerville Inst DE brain-computer interfaces (BCI); electroencephalogram (EEG); kernel partial least squares (KPLS); steady-state visual evoked potentials (SSVEP) AB We have developed and tested two electroencephalogram (EEG)-based brain-computer interfaces (BCI) for users to control a cursor on a computer display. Our system uses an adaptive algorithm, based on kernel partial least squares classification (KPLS), to associate patterns in multichannel EEG frequency spectra with cursor controls. Our first BCI, Target Practice, is a system for one-dimensional device control, in which participants use biofeedback to learn voluntary control of their EEG spectra. Target Practice uses a KPLS classifier to map power spectra of 62-electrode EEG signals to rightward or leftward position of a moving cursor on a computer display. Three subjects learned to control motion of a cursor on a video display in multiple blocks of 60 trials over periods of up to six weeks. The best subject's average skill in correct selection of the cursor direction grew from 58% to 88% after 13 training sessions. Target Practice also implements online control of two artifact sources: 1) removal of ocular artifact by linear subtraction of wavelet-smoothed vertical and horizontal electrooculograms (EOG) signals, 2) control of muscle artifact by inhibition of BCI training during periods of relatively high power in the 40-64 Hz band. The second BCI, Think Pointer, is a system for two-dimensional cursor control. Steady-state visual evoked potentials (SSVEP) are triggered by four flickering checkerboard stimuli located in narrow strips at each edge of the display. The user attends to one of the four beacons to initiate motion in the desired direction. The SSVEP signals are recorded from 12 electrodes located over the occipital region. A KPLS classifier is individually calibrated to map multichannel frequency bands of the SSVEP signals to right-left or up-down motion of a cursor on a computer display. The display stops moving when the user attends to a central fixation point. As for Target Practice, Think Pointer also implements wavelet-based online removal of ocular artifact; however, in Think Pointer muscle artifact is controlled via adaptive normalization of the SSVEP. Training of the classifier requires about 3 min. We have tested our system in real-time operation in three human subjects. Across subjects and sessions, control accuracy ranged from 80% to 100% correct with lags of 1-5 s for movement initiation and turning. We have also developed a realistic demonstration of our system for control of a moving map display (http://ti.are.nasa.gov/). C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Quantum Appl Sci & Res Inc, San Diego, CA 92121 USA. Austrian Res Inst Artificial Intelligence, A-1010 Vienna, Austria. QSS Grp Inc, Lanham, MD 20706 USA. RP Trejo, LJ (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM ltrejo@quasarusa.com; roman@ofai.at; bmatthews@mail.arc.nasa.gov RI Rosipal, Roman/B-8060-2008 NR 14 TC 103 Z9 106 U1 1 U2 19 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1534-4320 J9 IEEE T NEUR SYS REH JI IEEE Trans. Neural Syst. Rehabil. Eng. PD JUN PY 2006 VL 14 IS 2 BP 225 EP 229 DI 10.1109/TNSRE.2006.875578 PG 5 WC Engineering, Biomedical; Rehabilitation SC Engineering; Rehabilitation GA 054QW UT WOS:000238394700026 PM 16792300 ER PT J AU Polzin, KA Choueiri, EY AF Polzin, KA Choueiri, EY TI Performance optimization criteria for pulsed inductive plasma acceleration SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE acceleration modeling; nondimensional scaling parameters; pulsed inductive acceleration; pulsed plasma acceleration AB A model of pulsed inductive plasma thrusters consisting of a set of coupled circuit equations and a one-dimensional momentum equation has been nondimensionalized leading to the identification of several scaling parameters. Contour plots representing thruster performance (exhaust velocity and efficiency) were generated numerically as a function of the scaling parameters. The analysis revealed the benefits of underdamped current waveforms and led to an efficiency maximization criterion that requires the circuit's natural period to be matched to the acceleration timescale. It is also shown that the performance increases as a greater fraction of the propellant is-loaded nearer to the inductive acceleration coil. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Princeton Univ, Dept Mech & Aerosp Engn, Elect Prop & Plasma Dynam Lab, Princeton, NJ 08544 USA. RP Polzin, KA (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM kurt.a.polzin@nasa.gov; choueiri@princeton.edu NR 12 TC 11 Z9 11 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD JUN PY 2006 VL 34 IS 3 BP 945 EP 953 DI 10.1109/TPS.2006.875732 PN 3 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 057FY UT WOS:000238582900004 ER PT J AU Allan, BA Armstrong, R Bernholdt, DE Bertrand, F Chiu, K Dahlgren, TL Damevski, K Elwasif, WR Epperly, TGW Govindaraju, M Katz, DS Kohl, JA Krishnan, M Kumfert, G Larson, JW Lefantzi, S Lewis, MJ Malony, AD McInnes, LC Nieplocha, J Norris, B Parker, SG Ray, J Shende, S Windus, TL Zhou, SJ AF Allan, Benjamin A. Armstrong, Robert Bernholdt, David E. Bertrand, Felipe Chiu, Kenneth Dahlgren, Tamara L. Damevski, Kostadin Elwasif, Wael R. Epperly, Thomas G. W. Govindaraju, Madhusudhan Katz, Daniel S. Kohl, James A. Krishnan, Manoj Kumfert, Gary Larson, J. Walter Lefantzi, Sophia Lewis, Michael J. Malony, Allen D. McInnes, Lois C. Nieplocha, Jarek Norris, Boyana Parker, Steven G. Ray, Jaideep Shende, Sameer Windus, Theresa L. Zhou, Shujia TI A component architecture for high-performance scientific computing SO INTERNATIONAL JOURNAL OF HIGH PERFORMANCE COMPUTING APPLICATIONS LA English DT Review DE component architecture; combustion modeling; climate modeling; quantum chemistry; parallel computing ID MODEL; OPTIMIZATION; INTEGRATION; CHEMISTRY; CUMULVS AB The Common Component Architecture (CCA) provides a means for software developers to manage the complexity of large-scale scientific simulations and to move toward a plug-and-play environment for high-performance computing. In the scientific computing context, component models also promote collaboration using independently developed software, thereby allowing particular individuals or groups to focus on the aspects of greatest interest to them. The CCA supports parallel and distributed computing as well as local high-performance connections between components in a language-independent manner. The design places minimal requirements on components and thus facilitates the integration of existing code into the CCA environment. The CCA model imposes minimal overhead to minimize the impact on application performance. The focus on high performance distinguishes the CCA from most other component models. The CCA is being applied within an increasing range of disciplines, including combustion research, global climate simulation, and computational chemistry. C1 Sandia Natl Labs, Scalable Comp R&D, Livermore, CA 94551 USA. Oak Ridge Natl Lab, Div Math & Comp Sci, Oak Ridge, TN 37831 USA. Indiana Univ, Dept Comp Sci, Bloomington, IN 47405 USA. SUNY Binghamton, Dept Comp Sci, Binghamton, NY 13902 USA. Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94551 USA. Univ Utah, Sci Comp & Imaging Inst, Salt Lake City, UT 84112 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Sandia Natl Labs, Reacting Flow Res, Livermore, CA 94551 USA. Univ Oregon, Dept Comp & Informat Sci, Eugene, OR 97403 USA. Sandia Natl Labs, Adv Software R&D, Livermore, CA 94551 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Northrop Grumman Corp, Informat Technol Sector, Chantilly, VA 20151 USA. RP Allan, BA (reprint author), Sandia Natl Labs, Scalable Comp R&D, MS 9915,POB 969, Livermore, CA 94551 USA. RI Damevski, Kostadin/F-4476-2014; OI Damevski, Kostadin/0000-0001-7799-2026; Katz, Daniel S./0000-0001-5934-7525 NR 126 TC 68 Z9 69 U1 1 U2 14 PU SAGE PUBLICATIONS LTD PI LONDON PA 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND SN 1094-3420 EI 1741-2846 J9 INT J HIGH PERFORM C JI Int. J. High Perform. Comput. Appl. PD SUM PY 2006 VL 20 IS 2 BP 163 EP 202 DI 10.1177/1094342006064488 PG 40 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Computer Science, Theory & Methods SC Computer Science GA 052UQ UT WOS:000238259800002 ER PT J AU Chowdhury, FN Jiang, B Belcastro, CM AF Chowdhury, Fahmida N. Jiang, Bin Belcastro, Celeste M. TI Reduction of false alarms in fault detection problems SO INTERNATIONAL JOURNAL OF INNOVATIVE COMPUTING INFORMATION AND CONTROL LA English DT Article DE fault detection; false alarm; AR modeling ID SYSTEMS AB In this paper, we propose a new technique for enhancing the residual signal in a way that results in a reduced rate of false alarms. This is achieved by eliminating most of the noise from the residual signal through an autorgressive (AR) modeling. The AR model parameters are estimated in real time. Computer experiments using experimental data from NASA Langley Research Center are used to demonstrate an implementation of the proposed technique. C1 Univ Louisiana, Dept Elect & Comp Engn, Lafayette, LA 70504 USA. Nanjing Univ Aeronaut & Astronaut, Coll Automat Engn, Nanjing 210016, Peoples R China. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Chowdhury, FN (reprint author), Univ Louisiana, Dept Elect & Comp Engn, POB 43890, Lafayette, LA 70504 USA. EM fnchowdh@louisiana.edu; binjiang@nuaa.edu.cn; celeste.m.belcastro@larc.nasa.gov NR 13 TC 17 Z9 17 U1 0 U2 0 PU ICIC INTERNATIONAL PI KUMAMOTO PA KYUSHU TOKAI UNIV, 9-1-1, TOROKU, KUMAMOTO, 862-8652, JAPAN SN 1349-4198 J9 INT J INNOV COMPUT I JI Int. J. Innov. Comp. Inf. Control PD JUN PY 2006 VL 2 IS 3 BP 481 EP 490 PG 10 WC Automation & Control Systems; Computer Science, Artificial Intelligence SC Automation & Control Systems; Computer Science GA 108QX UT WOS:000242255400001 ER PT J AU Bakermans, C Ayala-del-rio, HL Ponder, MA Vishnivetskaya, T Gilichinsky, D Thomashow, MF Tiedje, JM AF Bakermans, C Ayala-del-rio, HL Ponder, MA Vishnivetskaya, T Gilichinsky, D Thomashow, MF Tiedje, JM TI Psychrobacter cryohalolentis sp nov and Psychrobacter arcticus sp nov., isolated from Siberian permafrost SO INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY LA English DT Article ID PHYLOGENETIC ANALYSIS; SPECIES DEFINITION; BACTERIA; STRAINS; SEA; ENVIRONMENTS; IMMOBILIS; SEQUENCES; COMMUNITY; GENES AB Three Gram-negative, non-motile, non-pigmented, oxidase-positive coccobacilli capable of growth at temperatures from -10 to 30 degrees C and salinities of 0 to 1(.)7 M NaCl were isolated from Siberian permafrost and characterized. Both 16S rRNA and gyrB gene sequencing studies placed the isolates in the Gammaproteobacteria within the genus Psychrobacter. However, with higher bootstrap values and reproducible tree topologies, gyrB represented a more reliable phylogenetic marker for the taxonomy of Psychrobacter species. DNA-DNA hybridization data supported gyrB tree topologies and established two relatedness groups within the three isolates; neither of these groups was related at the species level to any previously described Psychrobacter species. The two groups of isolates could be differentiated phenotypically from 13 previously described Psychrobacter species using API strips. These results support the existence of two novel species of Psychrobacter, for which we propose the names Psychrobacter cryohalolentis sp. nov. (type strain K5(T) = DSM 17306(T) =VKM B-2378(T)) and Psychrobacter arcticus sp. nov. (type strain 273-4(T) =DSM 17307(T) =VKM B-2377(T)). C1 Michigan State Univ, Ctr Microbial Ecol, E Lansing, MI 48824 USA. Michigan State Univ, NASA, Astrobiol Inst, E Lansing, MI 48824 USA. Univ Puerto Rico, Dept Biol, Humacao, PR 00791 USA. N Carolina State Univ, Dept Food Sci, Raleigh, NC 27695 USA. Russian Acad Sci, Inst Phys Chem & Biol Problems Soil Sci, Pushchino, Moscow Region, Russia. RP Bakermans, C (reprint author), Michigan State Univ, Ctr Microbial Ecol, E Lansing, MI 48824 USA. EM bakerm16@msu.edu RI Vishnivetskaya, Tatiana/A-4488-2008 OI Vishnivetskaya, Tatiana/0000-0002-0660-023X NR 35 TC 70 Z9 78 U1 3 U2 10 PU SOC GENERAL MICROBIOLOGY PI READING PA MARLBOROUGH HOUSE, BASINGSTOKE RD, SPENCERS WOODS, READING RG7 1AG, BERKS, ENGLAND SN 1466-5026 J9 INT J SYST EVOL MICR JI Int. J. Syst. Evol. Microbiol. PD JUN PY 2006 VL 56 BP 1285 EP 1291 DI 10.1099/ijs.0.64043-0 PN 6 PG 7 WC Microbiology SC Microbiology GA 055UE UT WOS:000238475200019 PM 16738105 ER PT J AU Riishojgaard, LP Atlas, R Emmitt, GD AF Riishojgaard, LP Atlas, R Emmitt, GD TI TRMM calibration of SSM/I algorithm for overland rainfall estimation - Reply SO JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY LA English DT Editorial Material ID LEVEL METEOROLOGICAL ANALYSIS; LIDAR WIND OBSERVATIONS; IMPACT C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. Simpson Weather Associates Inc, Charlottesville, VA USA. RP Riishojgaard, LP (reprint author), NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Mail Code 610-1, Greenbelt, MD 20771 USA. EM larspr@gmao.gsfc.nasa.gov RI Atlas, Robert/A-5963-2011 OI Atlas, Robert/0000-0002-0706-3560 NR 2 TC 0 Z9 0 U1 0 U2 0 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 JUN PY 2006 VL 45 IS 6 BP 887 EP 888 DI 10.1175/JAM2358.1 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 057FD UT WOS:000238580800007 ER PT J AU Austin, AJ Nguyen, CV Ngo, Q AF Austin, AJ Nguyen, CV Ngo, Q TI Electrical conduction of carbon nanotube atomic force microscopy tips: Applications in nanofabrication SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SCANNING PROBE MICROSCOPY; LATERAL RESOLUTION; OXIDATION; SILICON; NANOLITHOGRAPHY; FABRICATION; CAPACITANCE; BREAKDOWN; DYNAMICS; DEVICES AB This paper reports the electrical transport properties of the interface of a multiwalled carbon nanotube (MWNT) in physical end contact with a hydrogen-passivated Si surface and a Pt surface. The electrical measurement was performed in an atomic force microscope (AFM) with a MWNT attached to a scanning probe in contact mode at approximately 50% relative humidity. AFM force-distance spectroscopy was employed to set the degree of contact between the MWNT tip with the surface. The tip-substrate interface dominates the electrical measurement in this configuration, showing electrical conductivity characteristics indicative of the tip-substrate junction. MWNT tips in contact with a Pt surface exhibit a linear I-V behavior with electrical resistances in the range of 30-50 k Omega, demonstrating the metallic nature of the MWNT. Results are presented for the investigation of the current-induced joule heating limitations of MWNT tips under ambient conditions. Thinning of the outer walls through a current-induced thermal oxidation process is observed at a current greater than 5 mu A, exhibiting a current density of greater than 10(6) A/cm(2). For a MWNT tip in end contact with a highly p-doped silicon surface, a diode-like metal-insulator-semiconductor (MIS) junction is measured. Modeling of the MIS junction is presented and compared to the experiments. (c) 2006 American Institute of Physics. C1 NASA, Ames Res Ctr, ELORET Corp, NASA Ames Ctr Nanotechnol, Moffett Field, CA 94035 USA. Santa Clara Univ, Ctr Nanostruct, Santa Clara, CA 94050 USA. RP Nguyen, CV (reprint author), NASA, Ames Res Ctr, ELORET Corp, NASA Ames Ctr Nanotechnol, M-S 229-1, Moffett Field, CA 94035 USA. EM cvnguyen@mail.arc.nasa.gov NR 40 TC 15 Z9 16 U1 0 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 2006 VL 99 IS 11 AR 114304 DI 10.1063/1.2195123 PG 9 WC Physics, Applied SC Physics GA 053OQ UT WOS:000238314900083 ER PT J AU Figueroa-Feliciano, E AF Figueroa-Feliciano, E TI Complex microcalorimeter models and their application to position-sensitive detectors SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID THERMAL DETECTORS; RAY AB We present a general formalism for calculating the linear response, noise spectrum, and energy resolution of complex calorimeters. Using this formalism calorimeters with arbitrary numbers of distinct linked heat capacity systems and/or coupled thermometers can be analyzed. We use this formalism to derive the theoretical resolution of an imaging microcalorimeter called a position-sensitive transition-edge sensor. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20770 USA. RP Figueroa-Feliciano, E (reprint author), MIT, Kavli Inst Astrophys & Space Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA. EM enectali@mit.edu NR 16 TC 17 Z9 17 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 2006 VL 99 IS 11 AR 114513 DI 10.1063/1.2191449 PG 11 WC Physics, Applied SC Physics GA 053OQ UT WOS:000238314900110 ER PT J AU Liu, Y Kauser, MZ Schroepfer, DD Ruden, PP Xie, J Moon, YT Onojima, N Morkoc, H Son, KA Nathan, MI AF Liu, Y. Kauser, M. Z. Schroepfer, D. D. Ruden, P. P. Xie, J. Moon, Y. T. Onojima, N. Morkoc, H. Son, K. -A. Nathan, M. I. TI Effect of hydrostatic pressure on the current-voltage characteristics of GaN/AlGaN/GaN heterostructure devices SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID P-TYPE GAN; ELASTIC-CONSTANTS; UNIAXIAL-STRESS; DEPENDENCE; ALN; CONDUCTIVITY; POLARIZATION; DENSITY; LAYERS AB The current-voltage characteristics of n-GaN/u-AlGaN/n-GaN heterostructure devices are investigated for potential pressure sensor applications. Model calculations suggest that the current decreases with pressure as a result of the piezoelectric effect, and this effect becomes more significant with thicker AlGaN layers and increasing AlN composition. The change in current with pressure is shown to be highly sensitive to the change in interfacial polarization charge densities. The concept is verified by measuring the current versus voltage characteristics of an n-GaN/u-Al0.2Ga0.8N/n-GaN device under hydrostatic pressure over the range of 0-5 kbars. The measured current is found to decrease approximately linearly with applied pressure in agreement with the model results. A gauge factor, which is defined as the relative change in current divided by the in-plane strain, approaching 500 is extracted from the data, demonstrating the considerable potential of these devices for pressure sensing applications. (c) 2006 American Institute of Physics. C1 Univ Minnesota, Dept Elect & Comp Engn, Minneapolis, MN 55455 USA. Virginia Commonwealth Univ, Dept Elect Engn, Richmond, VA 23284 USA. Jet Propuls Lab, Pasadena, CA 91109 USA. IBM Corp, Thomas J Watson Res Ctr, Yorktown Hts, NY 10598 USA. RP Liu, Y (reprint author), Univ Minnesota, Dept Elect & Comp Engn, Minneapolis, MN 55455 USA. EM liux0280@umn.edu NR 26 TC 18 Z9 18 U1 2 U2 18 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 2006 VL 99 IS 11 AR 113706 DI 10.1063/1.2200742 PG 5 WC Physics, Applied SC Physics GA 053OQ UT WOS:000238314900055 ER PT J AU Zhao, GL Bagayoko, D Yang, L AF Zhao, G. L. Bagayoko, D. Yang, L. TI Optical properties of aligned carbon nanotube mats for photonic applications SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ELECTRONIC-STRUCTURE; ENERGIES; FILMS AB We studied the optical properties of the aligned carbon nanotube (16, 0), (10, 0), and (8, 4) mats for photonic device applications. We employed ab initio density functional potentials and utlized the linear combination of atomic orbital formalism. We calculated the electronic structure of the carbon nanotube mats and the real and imaginary parts of the dielectric functions as functions of the photon energy. The calculated dielectric functions of the aligned carbon nanotube mats show a strong anisotropy when the electric field of the light is parallel or perpendicular to the tube axes. Especially, there are strong peaks in the imaginary part of the dielectric function near the absorption edges, when the electric field of the light is parallel to the carbon nanotube axes. The unusual optical properties of the semiconducting carbon nanotube mats present an opportunity for applications in electro-optical devices in the infrared energy region. (c) 2006 American Institute of Physics. C1 So Univ & A & M Coll, Dept Phys, Baton Rouge, LA 70813 USA. NASA, Ames Res Ctr, Eloret, Moffett Field, CA 94035 USA. RP Zhao, GL (reprint author), So Univ & A & M Coll, Dept Phys, Baton Rouge, LA 70813 USA. EM zhao@grant.phys.subr.edu NR 27 TC 16 Z9 16 U1 0 U2 5 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 2006 VL 99 IS 11 AR 114311 DI 10.1063/1.2201738 PG 5 WC Physics, Applied SC Physics GA 053OQ UT WOS:000238314900090 ER PT J AU Gopalswamy, N AF Gopalswamy, Nat TI Proceedings of the International Solar Workshop on Transient Phenomena on the Sun and Interplanetary Medium - April 5-7, 2005 - Aryabhatta Research Institute of Observational Sciences (ARIES) - Manora Peak, Nainital, India - Preface SO JOURNAL OF ASTROPHYSICS AND ASTRONOMY LA English DT Editorial Material C1 NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Greenbelt, MD 20771 USA. RP Gopalswamy, N (reprint author), NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Greenbelt, MD 20771 USA. RI Gopalswamy, Nat/D-3659-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU INDIAN ACADEMY SCIENCES PI BANGALORE PA C V RAMAN AVENUE, SADASHIVANAGAR, P B #8005, BANGALORE 560 080, INDIA SN 0250-6335 J9 J ASTROPHYS ASTRON JI J. Astrophys. Astron. PD JUN-SEP PY 2006 VL 27 IS 2-3 BP 57 EP 58 DI 10.1007/BF02702507 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 095FP UT WOS:000241293900002 ER PT J AU Gopalswamy, N AF Gopalswamy, Nat TI Coronal mass ejections of solar cycle 23 SO JOURNAL OF ASTROPHYSICS AND ASTRONOMY LA English DT Article; Proceedings Paper CT International Solar Workshop on Transient Phenomena on the Sun and Interplanetary Medium CY APR 05-07, 2005 CL Aryabhatta Res Inst Observat Sci, Manora Peak, INDIA HO Aryabhatta Res Inst Observat Sci DE Sun : coronal mass ejections; shocks; magnetic field ID SOLAR-CYCLE; MAGNETIC STORMS; EVENTS; SPEEDS; ACCELERATION; DISTURBANCES; MODULATION; TRANSIENTS; LASCO; SHOCK AB I summarize the statistical, physical, and morphological properties of coronal mass ejections (CMEs) of solar cycle 23, as observed by the Solar and Heliospheric Observatory (SOHO) mission. The SOHO data is by far the most extensive data, which made it possible to fully establish the properties of CMEs as a phenomenon of utmost importance to Sun-Earth connection as well as to the heliosphere. I also discuss various subsets of CMEs that are of primary importance for their impact on Earth. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gopalswamy, N (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM gopals@ssedmail.gsfc.nasa.gov RI Gopalswamy, Nat/D-3659-2012 NR 50 TC 81 Z9 84 U1 1 U2 5 PU INDIAN ACAD SCIENCES PI BANGALORE PA C V RAMAN AVENUE, SADASHIVANAGAR, P B #8005, BANGALORE 560 080, INDIA SN 0250-6335 J9 J ASTROPHYS ASTRON JI J. Astrophys. Astron. PD JUN-SEP PY 2006 VL 27 IS 2-3 BP 243 EP 254 DI 10.1007/BF02702527 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 095FP UT WOS:000241293900022 ER PT J AU Kim, SB Fukumori, I Lee, T AF Kim, SB Fukumori, I Lee, T TI The closure of the ocean mixed layer temperature budget using level-coordinate model fields SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID SEA-SURFACE TEMPERATURE; KUROSHIO EXTENSION REGION; TROPICAL PACIFIC; HEAT-BALANCE; EQUATORIAL PACIFIC; EL-NINO; VARIABILITY; CYCLE; SST AB Entrainment is an important element of the mixed layer mass, heat, and temperature budgets. Conventional procedures to estimate entrainment heat advection often do not permit the closure of heat and temperature budgets because of inaccuracies in its formulation. In this study a rigorous approach to evaluate the effect of entrainment using the output of a general circulation model ( GCM) that does not have an explicit prognostic mixed layer model is described. The integral elements of the evaluation are 1) the rigorous estimates of the temperature difference between mixed layer water and entrained water at each horizontal grid point, 2) the formulation of the temperature difference such that the budget closes over a volume greater than one horizontal grid point, and 3) the apparent warming of the mixed layer during the mixed layer shoaling to account for the weak vertical temperature gradient within the mixed layer. This evaluation of entrainment heat advection is compared with the estimates by other commonly used ad hoc formulations by applying them in three regions: the north-central Pacific, the Kuroshio Extension, and the Nino-3 areas in the tropical Pacific. In all three areas the imbalance in the mixed layer temperature budget by the ad hoc estimates is significant, reaching a maximum of about 4 K yr(-1). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Kim, SB (reprint author), Remote Sensing Syst, 438 1st St,Suite 200, Santa Rosa, CA 95401 USA. EM kim@remss.com NR 29 TC 19 Z9 20 U1 0 U2 3 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 JUN PY 2006 VL 23 IS 6 BP 840 EP 853 DI 10.1175/JTECH1883.1 PG 14 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 060EO UT WOS:000238785400008 ER PT J AU Wu, DL AF Wu, Dong L. TI Small-scale fluctuations and scintillations in high-resolution GPS/CHAMP SNR and phase data SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article DE scintillation; gravity wave; GPS radio occultation; ionosphere; troposphere ID GPS/MET RADIO OCCULTATION; GLOBAL POSITIONING SYSTEM; GRAVITY-WAVE ACTIVITY; SPORADIC-E; ELECTRON-DENSITY; GPS OCCULTATION; SATELLITE-OBSERVATIONS; TROPICAL TROPOPAUSE; E-LAYER; CHAMP AB This paper analyzes small-scale fluctuations that appear in the signal-to-noise ratio (SNR) and,phase measurements during GPS/CHAMP radio occultation through the E-region ionosphere, lower stratosphere, and upper troposphere. Analyses are based on the raw 50-Hz SNR and phase data, which reveal new information on variations and distributions of small-scale atmospheric/iono spheric variabilities that would be normally discarded in the retrieved temperature profiles. The derived SNR and phase variances show strong annual and interannual variations in the ionosphere due to solar-cycle modulated sporadic-E activity. The intensity of polar E-s activity reduced gradually since 2001, as solar activity weakened from the 2000 maximum. In the upper troposphere, the small-scale SNR and phase variances maximize near the tropical tropopause and vary strongly with seasonal variations of the tropopause. In the tropical lower stratosphere, the variances exhibit a quasi-biannual oscillation (QBO) with amplitude maximized at altitudes of 15-30 km and progressing downward in time. The downward-progressing amplitude occurs just below the height of zero-wind line where QBO changes phase from the easterly to the westerly. Physical interpretation of SNR and phase variances is made with analytical expressions derived for idealized small-scale ionospheric and atmospheric perturbations. In these cases, the SNR standard deviation is inversely proportional to vertical wavelength of perturbations whereas the phase one is proportional to the truncation length used for variance calculations. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. RP Wu, DL (reprint author), CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. EM dwu@mls.jpl.nasa.gov RI Wu, Dong/D-5375-2012 NR 40 TC 11 Z9 11 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 EI 1879-1824 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD JUN PY 2006 VL 68 IS 9 BP 999 EP 1017 DI 10.1016/j.jastp.2006.01.006 PG 19 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 053UQ UT WOS:000238331600005 ER PT J AU Rajamohan, D Banerjee, RK Back, LH Ibrahim, AA Jog, MA AF Rajamohan, D Banerjee, RK Back, LH Ibrahim, AA Jog, MA TI Developing pulsatile flow in a deployed coronary stent SO JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID COMPUTATIONAL FLUID-DYNAMICS; SHEAR-STRESS; WALL SHEAR; IMPLANTATION; RESTENOSIS; VESSEL; BLOOD; THICKNESS; STENOSES; DESIGN AB A major consequence of stent implantation is restenosis that occurs due to neointimal formation. This patho-physiologic process of tissue growth may not be completely eliminated. Recent evidence suggests that there are several factors such as geometry and size of vessel, and stent design that alter hemodynamic parameters, including local wall shear stress distributions, all of which influence the restenosis process. The present three-dimensional analysis of developing pulsatile flow in a deployed coronary stent quantifies hemodynamic parameters and illustrates the changes in local wall shear stress distributions and their impact on restenosis. The present model evaluates the effect of entrance flow, where the stent is placed at the entrance region of a branched coronary artery Stent geometry, showed a complex three-dimensional variation of wall shear stress distributions within the stented region. Higher order of magnitude of wall shear stress of 530 dyn/cm(2) is observed on the surface of cross-link intersections at the entrance of the stent. A low positive wall shear stress of 10 dyn/cm(2) and a negative wall shear stress of -10 dyn/cm(2) are seen at the immediate upstream and downstream regions of strut intersections, respectively. Modified oscillatory shear index is calculated which showed persistent recirculation at the downstream region of each strut intersection. The portions of the vessel where there is low and negative wall shear stress may represent locations of thrombus formation and platelet accumulation. The present results indicate that the immediate downstream. regions of strut intersections are areas highly susceptible to restenosis, whereas a high shear stress at the strut intersection may cause platelet activation and free emboli formation. C1 Univ Cincinnati, Dept Mech Engn, Cincinnati, OH 45221 USA. Univ Cincinnati, Dept Biomed Engn, Cincinnati, OH 45221 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Banerjee, RK (reprint author), Univ Cincinnati, Dept Mech Engn, 688 Rhodes Hall,POB 210072, Cincinnati, OH 45221 USA. EM rupak.banerjee@uc.edu NR 28 TC 20 Z9 22 U1 2 U2 7 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0148-0731 J9 J BIOMECH ENG-T ASME JI J. Biomech. Eng.-Trans. ASME PD JUN PY 2006 VL 128 IS 3 BP 347 EP 359 DI 10.1115/1.2194067 PG 13 WC Biophysics; Engineering, Biomedical SC Biophysics; Engineering GA 049UG UT WOS:000238042200008 PM 16706584 ER PT J AU Rasch, PJ Stevens, MJ Ricciardulli, L Dai, A Negri, A Wood, R Boville, BA Eaton, B Hack, JJ AF Rasch, Philip J. Stevens, Mark J. Ricciardulli, Lucrezia Dai, Aiguo Negri, Andrew Wood, Robert Boville, Byron A. Eaton, Brian Hack, James J. TI A characterization of tropical transient activity in the CAM3 atmospheric hydrologic cycle SO JOURNAL OF CLIMATE LA English DT Article ID GENERAL-CIRCULATION MODEL; DIURNAL CYCLE; GLOBAL PRECIPITATION; INFRARED WINDOW; DEEP CONVECTION; CLOUD CLUSTERS; IN-SITU; RAINFALL; SATELLITE; TRMM AB The Community Atmosphere Model version 3 (CAM3) is the latest generation of a long lineage of general circulation models produced by a collaboration between the National Center for Atmospheric Research (NCAR) and the scientific research community. Many aspects of the hydrological cycle have been changed relative to earlier versions of the model. It is the goal of this paper to document some aspects of the tropical variability of clouds and the hydrologic cycle in CAM3 on time scales shorter than 30 days and to discuss the differences compared to the observed atmosphere and earlier model versions, with a focus on cloud-top brightness temperature, precipitation, and cloud liquid water path. The transient behavior of the model in response to changes in resolution to various numerical methods used to solve the equations for atmospheric dynamics and transport and to the underlying lower boundary condition of sea surface temperature and surface fluxes has been explored. The ratio of stratiform to convective rainfall is much too low in CAM3, compared to observational estimates. It is much higher in CAM3 (10%) than the Community Climate Model version 3 (CCM3; order 1%-2%) but is still a factor of 4-5 too low compared to observational estimates. Some aspects of the model transients are sensitive to resolution. Higher-resolution versions of CAM3 show too much variability (both in amplitude and spatial extent) in brightness temperature on time scales of 2-10 days compared to observational estimates. Precipitation variance is underestimated on time scales from a few hours to 10 days, compared to observations over ocean, although again the biases are reduced compared to previous generations of the model. The diurnal cycle over tropical landmasses is somewhat too large, and there is not enough precipitation during evening hours. The model tends to produce maxima in precipitation and liquid water path that are a few hours earlier than that seen in the observations over both oceans and land. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Remote Sensing Syst, Santa Rosa, CA USA. NASA, Goddard Space Flight Ctr, Lab Atmosphere, Greenbelt, MD 20771 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. RP Rasch, PJ (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. EM pjr@ucar.edu RI Wood, Robert/A-2989-2008; Dai, Aiguo/D-3487-2009 OI Wood, Robert/0000-0002-1401-3828; NR 47 TC 29 Z9 29 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 EI 1520-0442 J9 J CLIMATE JI J. Clim. PD JUN 1 PY 2006 VL 19 IS 11 BP 2222 EP 2242 DI 10.1175/JCLI3752.1 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 051FY UT WOS:000238148200007 ER PT J AU Shi, J Kelkar, AG Soloway, D AF Shi, J Kelkar, AG Soloway, D TI Stable reconfigurable generalized predictive control with application to flight control SO JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME LA English DT Article ID CONSTRAINED NONLINEAR-SYSTEMS; RECEDING HORIZON CONTROL; FEEDBACK STABILIZATION; GUARANTEED STABILITY; CGPC AB This paper presents the development of a multiinput multioutput generalized predictive control (GPC) law and its application to reconfigurable control design in the event of actuator saturation. The stability of the GPC control law without reconfiguration is first established using an end-point state weighting. Based on the constrained nonlinear optimization, an end-point state weighting matrix synthesis method is derived. A novel reconfiguration strategy is developed for systems that have actuator redundancy and are faced with actuator saturation type failure. An elegant reconfigurable control design is p. resented with stability proof. A numerical simulation using a short-period approximation model of a civil transport aircraft is presented to demonstrate the reconfigurable control architecture. C1 Iowa State Univ, Ames, IA 50011 USA. NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94035 USA. RP Shi, J (reprint author), Iowa State Univ, Ames, IA 50011 USA. EM rabbitsj@iastate.edu; akelkar@iastate.edu; don@email.arc.nasa.gov NR 26 TC 3 Z9 5 U1 1 U2 6 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0022-0434 J9 J DYN SYST-T ASME JI J. Dyn. Syst. Meas. Control-Trans. ASME PD JUN PY 2006 VL 128 IS 2 BP 371 EP 378 DI 10.1115/1.2194076 PG 8 WC Automation & Control Systems; Instruments & Instrumentation SC Automation & Control Systems; Instruments & Instrumentation GA 058KY UT WOS:000238665100020 ER PT J AU Koch, GJ AF Koch, Grady J. TI Using a Doppler light detection and ranging (lidar) system to characterize an atmospheric thermal providing lift for soaring raptors SO JOURNAL OF FIELD ORNITHOLOGY LA English DT Article DE Doppler lidar; imaging; light detection and ranging system; soaring; thermal ID FLIGHT AB Raptors and other large birds in soaring flight take advantage of upward drafts of air called thermals to maintain altitude with minimal flapping. I us;e a Doppler light detection and ranging (lidar) system to characterize a thermal in which raptors were soaring. Doppler lidar allows imaging of wind fields to reveal the structure of updrafts and downdrafts in a thermal. The thermal I monitored was in the form of a horizontal convective roll created at a transition from clear sky to partly cloudy sky, and gave both lift and lateral motion to the soaring birds. The thermal was 700 in high with a vertical wind speed that peaked at 3 m/s, so raptors could have soared to and maintained that altitude as the horizontal wind moved the thermal. My results suggest that imaging wind fields with Doppler lidar can be a useful tool for studying thermals and how they are used by soaring birds. An effective combination for further study of bird flight interaction with wind phenomena would be to add lidar measurements to an established means of tracking bird flight by radio or GPS transmitters, aircraft tracking, or radar. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Koch, GJ (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM grady.j.koch@nasa.gov NR 7 TC 3 Z9 3 U1 1 U2 5 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0273-8570 J9 J FIELD ORNITHOL JI J. Field Ornithol. PD SUM PY 2006 VL 77 IS 3 BP 315 EP 318 DI 10.1111/j.1557-9263.2006.00058.x PG 4 WC Ornithology SC Zoology GA 087GF UT WOS:000240730200011 ER PT J AU Bosilovich, MG Chern, JD AF Bosilovich, Michael G. Chern, Jiun-Dar TI Simulation of water sources and precipitation recycling for the MacKenzie, Mississippi, and Amazon River basins SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article; Proceedings Paper CT 2nd International Workshop on Catchment-Scale Hydrological Modeling and Data Assimilation CY OCT 25-27, 2004 CL Princeton Univ, Princeton, NJ HO Princeton Univ ID COMMUNITY CLIMATE MODEL; WARM-SEASON PRECIPITATION; COMMON LAND MODEL; UNITED-STATES; SURFACE-TEMPERATURE; HYDROLOGIC-CYCLE; SOIL-MOISTURE; GLOBAL-MODELS; VARIABILITY; DROUGHT AB An atmospheric general circulation model simulation for 1948 - 97 of the water budgets for the MacKenzie, Mississippi, and Amazon River basins is presented. In addition to the water budget, passive tracers are included to identify the geographic sources of water for the basins, and the analysis focuses on the mechanisms contributing to precipitation recycling in each basin. While each basin's precipitation recycling has a strong dependency on evaporation during the mean annual cycle, the interannual variability of the recycling shows important relationships with the atmospheric circulation. The MacKenzie River basin recycling has only a weak interannual correspondence with evaporation, where the variations in zonal moisture transport from the Pacific Ocean can affect the basin water cycle. On the other hand, the Mississippi River basin precipitation and recycling have strong interannual correlation on evaporation. The evaporation is related to the moist and shallow planetary boundary layer that provides moisture for convection at the cloud base. At global scales, high precipitation recycling is also found to be partly correlated to warm SSTs in the tropical Pacific Ocean. The Amazon River basin evaporation exhibits small interannual variations, so the interannual variations of precipitation recycling are related to atmospheric moisture transport from the tropical South Atlantic Ocean. Increasing SSTs over the 50-yr period are causing increased easterly transport across the basin. As moisture transport increases, the Amazon precipitation recycling decreases ( without real-time varying vegetation changes). In addition, precipitation recycling from a bulk diagnostic method is compared to the passive tracer method used in the analysis. While the mean values of the different recycling methods are different, the interannual variations are comparable between each method. The methods also exhibit similar relationships to the terms of the basin-scale water budgets. C1 NASA, Global Modeling & Assimilat Off, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Bosilovich, MG (reprint author), NASA, Global Modeling & Assimilat Off, Goddard Space Flight Ctr, Code 610-1, Greenbelt, MD 20771 USA. EM Michael.Bosilovich@nasa.gov RI Bosilovich, Michael/F-8175-2012 NR 45 TC 34 Z9 35 U1 0 U2 11 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X EI 1525-7541 J9 J HYDROMETEOROL JI J. Hydrometeorol. PD JUN PY 2006 VL 7 IS 3 BP 312 EP 329 DI 10.1175/JHM501.1 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 058UJ UT WOS:000238689800002 ER PT J AU Turner, TL Buehrle, RD Cano, RJ Fleming, GA AF Turner, TL Buehrle, RD Cano, RJ Fleming, GA TI Modeling, fabrication, and testing of a SMA hybrid composite jet engine chevron concept SO JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES LA English DT Article ID SHAPE CONTROL; BEAMS; ACTUATION AB This study presents a fabrication method, bench top test results, and numerical model validation for a novel adaptive jet engine chevron concept based upon embedding shape memory alloy (SMA) actuators in a composite laminate, termed a SMA hybrid composite (SMAHC). The approach for fabricating the adaptive SMAHC chevrons involves embedding prestrained Nitinol actuators on one side of the mid-plane of the composite laminate such that thermal excitation generates a thermal moment and deflects the structure. A rigorous and versatile test system for control and measurement of the chevron deflection performance is described. A recently commercialized constitutive model for SMA and SMAHC materials is used in the finite element code ABAQUS to perform nonlinear static analysis of the chevron specimens. Excellent agreement is achieved between the predicted and measured chevron deflection performance, thereby validating the numerical model and enabling detailed design of chevron prototype(s) and similar structures. C1 NASA, Langley Res Ctr, Struct Acoust Branch, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Adv Sensing & Opt Measurement Branch, Hampton, VA 23681 USA. RP Turner, TL (reprint author), NASA, Langley Res Ctr, Struct Acoust Branch, Hampton, VA 23681 USA. EM t.l.turner@nasa.gov NR 21 TC 30 Z9 30 U1 0 U2 4 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 JUN PY 2006 VL 17 IS 6 BP 483 EP 497 DI 10.1177/1045389X06058795 PG 15 WC Materials Science, Multidisciplinary SC Materials Science GA 050VA UT WOS:000238115800003 ER PT J AU Basu, S Waas, AM Ambur, DR AF Basu, Shiladitya Waas, Anthony M. Ambur, Damodar R. TI A MACROSCOPIC MODEL FOR KINK BANDING INSTABILITIES IN FIBER COMPOSITES SO JOURNAL OF MECHANICS OF MATERIALS AND STRUCTURES LA English DT Article DE fiber kinking; fiber rotation; matrix damage; progressive failure analysis; compressive response AB In this paper, a mechanism-based lamina level modeling approach is used as the basis for developing a macroscopic (lamina level) model to capture the mechanisms of kink banding. Laminae are modeled as inelastic degrading homogenized layers in a state of plane stress according to Schapery Theory (ST). However, the principal orthotropic material axes are allowed to rotate as a function of deformation. In ST, each lamina degrades as characterized through laboratory scale experiments. In the fiber direction, elastic behavior prevails; however, in this work, the phenomenon of fiber microbuckling leading to kink banding, 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. These features are built into a user-defined material subroutine that is implemented through the commercial finite element (FE) software ABAQUS. Thus, in this model we eschew the notion of a fixed compressive strength of a lamina and instead use 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 this model are laboratory scale, coupon level test data (at the lamina level) that provide information on the lamina transverse property degradation (that is, appropriate, measured, strain-stress relations of the lamina transverse properties), the elastic lamina orthotropic properties and the geometry of the lamina. The validity of the approach advocated is demonstrated through numerical simulations of unidirectional lamina with initial fiber imperfections. The predictions of the simulations reported in this paper are compared against previously reported results from micromechanical analyses. Good agreement between the present macroscopic modeling approach and the previous micromechanical observations are reported. C1 [Basu, Shiladitya] Granherne Inc, Tech Profess Marine, Houston, TX 77054 USA. [Waas, Anthony M.] Univ Michigan, Dept Aerosp Engn, Composite Struct Lab, Ann Arbor, MI 48109 USA. [Ambur, Damodar R.] NASA Glenn Res Ctr, Struct Div, Cleveland, OH 44135 USA. RP Basu, S (reprint author), Granherne Inc, Tech Profess Marine, 601 Jefferson Ave, Houston, TX 77054 USA. EM basus@umich.edu; dcw@umich.edu; damodar.r.ambur@nasa.gov NR 28 TC 7 Z9 7 U1 2 U2 7 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 JUN PY 2006 VL 1 IS 6 BP 979 EP 1000 DI 10.2140/jomms.2006.1.979 PG 22 WC Materials Science, Multidisciplinary; Mechanics SC Materials Science; Mechanics GA V14IR UT WOS:000207728600002 ER PT J AU Lee, C Yang, EH Saeidi, SM Khodadadi, JM AF Lee, C Yang, EH Saeidi, SM Khodadadi, JM TI Fabrication, characterization, and computational modeling of a piezoelectrically actuated microvalve for liquid flow control SO JOURNAL OF MICROELECTROMECHANICAL SYSTEMS LA English DT Article DE computational fluid dynamics (CFD); liquid-compatible; liquid flow; low-power consumption; piezoelectric; proportional flow control; microfluidics; microvalve; modeling AB Liquid-compatible piezoelectric microvalves have been modeled, fabricated, and characterized. The microvalve was designed for proportional flow control of liquid propellant for integrated spacecraft micropropulsion. The microvalve consists of a custom-designed piezoelectric stack actuator bonded onto silicon valve components with the entire assembly contained within a stainless steel housing. The valve seat configuration includes narrow-edge seating rings and tensile-stressed silicon tethers that enable the normally closed and leak-tight operation. A concentric series of narrow rings simulates a "knife-edge" seal by greatly reducing the valve contact area, thereby increasing the seating pressure and consequently reducing leak. Leak testing of the microvalve, conducted using a Helium leak detector, showed a leak rate of approximately 3 x 10(-6) scc/s for Helium gas. During operation, the valve flow rate was measured using an external Mass Flow Meter (MFM) with a measurement resolution of approximately 10(-2) scc/s. The measured forward flow rate for deionized (DI) water is approximately 64 mg/min at an inlet pressure of 20 psi and an applied voltage of 50 V. The mechanical resonance frequency of the microvalve structure was measured at 11.1 kHz. The measured dynamic power consumption of the microvalve is approximately 60 mW when operated at 50 Hz. The measured static power consumption is approximately 2.5 mW at 20 V. Computational modeling of liquid flow within the piezo-electrically actuated microvalve has also been performed. The commercial computational fluid dynamics (CFD) code FLUENT was utilized for solving the continuity and momentum equations. The pressure drop between the inlet and outlet ports was determined as a function of the inlet mass flow rate, and a pressure drop coefficient was determined for each valve plate deflection value. The model-predicted values were compared to the experimental data, and confirmed the sensitivity of the results to the value of the deflection. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Intel Corp, Assembly Technol Dev, Phoenix, AZ USA. Auburn Univ, Dept Mech Engn, Auburn, AL 36849 USA. RP Lee, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Eui-Hyeok.Yang@jpl.nasa.gov OI Yang, Eui-Hyeok/0000-0003-4893-1691 NR 19 TC 17 Z9 18 U1 1 U2 15 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1057-7157 J9 J MICROELECTROMECH S JI J. Microelectromech. Syst. PD JUN PY 2006 VL 15 IS 3 BP 686 EP 696 DI 10.1109/JMEMS.2006.876783 PG 11 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Instruments & Instrumentation; Physics, Applied SC Engineering; Science & Technology - Other Topics; Instruments & Instrumentation; Physics GA 053NE UT WOS:000238311000027 ER PT J AU Keller, LP Messenger, S AF Keller, Lindsay P. Messenger, Scott TI The nature of early solar system and presolar materials SO JOURNAL OF MINERALOGICAL AND PETROLOGICAL SCIENCES LA English DT Article DE comets; presolar grains; electron microscopy; isotope anomalies; stardust; interstellar dust ID INTERPLANETARY DUST PARTICLE; MOLECULAR-CLOUD MATERIAL; INTERSTELLAR-MEDIUM; MASSIVE STARS; METEORITES; GRAINS; CHONDRITES; SILICATES; STARDUST; NUCLEOSYNTHESIS AB Remnants of the materials that were present at the formation of the early solar system are preserved in cometary dust particles collected in the Earth's stratosphere. Coordinated analyses of these materials using ion and electron beam instruments have identified preserved circumstellar silicates, supernova grains, and molecular cloud organic matter within the particles. These exotic grains have isotopic compositions that lie far outside the range exhibited by solar system materials. The mineralogy, composition, and microstructure of the presolar grains provide additional insights their sources and formation. The laboratory data serve as ground truth for astrophysical models based on spectroscopic measurements. C1 NASA, Astromat Res & Explorat Sci Directorate, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Keller, LP (reprint author), NASA, Astromat Res & Explorat Sci Directorate, Lyndon B Johnson Space Ctr, Mail Code KR, Houston, TX 77058 USA. EM lindsay.p.keller@jsc.nasa.gov NR 39 TC 1 Z9 1 U1 0 U2 0 PU JAPAN ASSOC MINERALOGICAL SCIENCES PI SENDAI PA C/O GRAD SCH SCIENCES, TOHOKU UNIV, AOBA, SENDAI, 980-8578, JAPAN SN 1345-6296 EI 1349-3825 J9 J MINER PETROL SCI JI J. Mineral. Petrol. Sci. PD JUN PY 2006 VL 101 IS 3 BP 122 EP 129 DI 10.2465/jmps.101.122 PG 8 WC Mineralogy SC Mineralogy GA 057DG UT WOS:000238575900004 ER PT J AU Liu, CC Miller, RL Carder, KL Lee, ZP D'Sa, EJ Ivey, JE AF Liu, CC Miller, RL Carder, KL Lee, ZP D'Sa, EJ Ivey, JE TI Estimating the underwater light field from remote sensing of ocean color SO JOURNAL OF OCEANOGRAPHY LA English DT Article DE photosynthetically available radiation; ocean color; radiative transfer; ocean optics; compensation depth ID INHERENT OPTICAL-PROPERTIES; DIFFUSE ATTENUATION COEFFICIENT; WATERS; ABSORPTION; IRRADIANCE; MODEL; CHLOROPHYLL; ALGORITHMS; INVERSION; MATTER AB We present a new approach that incorporates two models to estimate the underwater light field from remote sensing of ocean color. The first employs a series of analytical, semi-analytical, and empirical algorithms to retrieve the spectrum of inherent optical properties (IOP's), including the absorption and the backscatter coefficients, from the spectrum of remote sensing reflectance. The second model computes the profile of photosynthetically available radiation E-0,E-PAR(z) for a vertically homogeneous water column using the information of the retrieved ION and the ambient optical environment. This computation is based on an improved look-up table technology that possesses high accuracy, comparable with the full solution of the radiative transfer equation, and meets the computational requirement of remote sensing application. This new approach was validated by in situ measurements and an extensive model-to-model comparison with a wide range of IOP's. We successfully mapped the compensation depth by applying this new approach to process the SeaWiFS imagery. This research suggests that E-0,E-PAR(z) can be obtained routinely from ocean-color data and may have significant implications for the estimation of global heat and carbon budget. C1 Natl Cheng Kung Univ, Dept Earth Sci, Tainan 701, Taiwan. Natl Cheng Kung Univ, Disaster Prevent Res Ctr, Tainan 701, Taiwan. Natl Cheng Kung Univ, Earth Dynam Syst Res Ctr, Tainan 701, Taiwan. NASA, Earth Sci Applicat Directorate, Stennis Space Ctr, MS 39529 USA. Univ S Florida, Coll Marine Sci, St Petersburg, FL 33701 USA. USN, Res Lab, Stennis Space Ctr, MS 39529 USA. Louisiana State Univ, Dept Oceanog & Coastal Sci, Baton Rouge, LA 70803 USA. RP Liu, CC (reprint author), Natl Cheng Kung Univ, Dept Earth Sci, Tainan 701, Taiwan. EM ccliu88@mail.ncku.edu.tw NR 39 TC 8 Z9 8 U1 1 U2 11 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO, 158-0083, JAPAN SN 0916-8370 J9 J OCEANOGR JI J. Oceanogr. PD JUN PY 2006 VL 62 IS 3 BP 235 EP 248 DI 10.1007/s10872-006-0048-4 PG 14 WC Oceanography SC Oceanography GA 038WR UT WOS:000237260700001 ER PT J AU Iyengar, MS Singhal, M AF Iyengar, MS Singhal, M TI Effect of network latency on load sharing in distributed systems SO JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING LA English DT Article DE queues latency; load sharing; load imbalance; load-sharing window; transfer pair; quantiles; multiple job transfer AB Distributed computing systems consist of computers interconnected by communications links. In such systems, Load sharing is an important technique used to improve system performance in which jobs are transferred from overloaded nodes, to, underloaded ones. However, due to the ubiquitous and inescapable presence of network latencies, various pitfalls arise which can adversely affect the beneficial effects of job transfer. In this paper, we present an investigation into the effect of network latency on load, sharing. The notions of Transfer Pair, and Load-Sharing Window are rigorously defined. A general expression for the probability distribution function of the Load-Sharing Window is derived. A class of rules. called quantile rules, is introduced and their role in avoiding unproductive job redistribution in spite of network latency, as well as to make multiple job transfers,. is explained. The general technique is applied to the specific case of a. distributed computing system consisting of M/M/1 queues. For this case, an expression for the mean of the Load-Sharing Window is derived, Numerical computations are presented, and their significance discussed. (C) 2005 Elsevier Inc. All rights reserved. C1 Univ Texas, Hlth Sci Ctr, Sch Hlth Informat Sci, Houston, TX 77059 USA. NASA, Lyndon B Johnson Space Ctr, Natl Space Biomed Res Inst, Houston, TX 77058 USA. Univ Kentucky, Dept Comp Sci, Lexington, KY 40506 USA. RP Iyengar, MS (reprint author), Univ Texas, Hlth Sci Ctr, Sch Hlth Informat Sci, 7000 Fannin,Suite 690, Houston, TX 77059 USA. EM msiriram@uth.tmc.edu NR 34 TC 3 Z9 3 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 0743-7315 J9 J PARALLEL DISTR COM JI J. Parallel Distrib. Comput. PD JUN PY 2006 VL 66 IS 6 BP 839 EP 853 DI 10.1016/j.jpdc.2005.09.005 PG 15 WC Computer Science, Theory & Methods SC Computer Science GA 049FH UT WOS:000238000800006 ER PT J AU Timonen, RS Leu, MT AF Timonen, RS Leu, MT TI Interaction of ethyl alcohol vapor with sulfuric acid solutions SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID UPPER TROPOSPHERE; DIFFUSION-COEFFICIENTS; LOWER STRATOSPHERE; HYDROGEN RADICALS; SULPHURIC ACID; UNITED-STATES; TRACE GASES; ACETONE; AEROSOLS; ESTERIFICATION AB We investigated the uptake of ethyl alcohol ( ethanol) vapor by sulfuric acid solutions over the range similar to 40 to similar to 80 wt % H2SO4 and temperatures of 193-273 K. Laboratory studies used a fast flow-tube reactor coupled to an electron-impact ionization mass spectrometer for detection of ethanol and reaction products. The uptake coefficients (gamma) were measured and found to vary from 0.019 to 0.072, depending upon the acid composition and temperature. At concentrations greater than similar to 70 wt % and in dilute solutions colder than 220 K, the gamma values approached similar to 0.07. We also determined the effective solubility constant of ethanol in similar to 40 wt % H2SO4 in the temperature range 203-223 K. The potential implications to the budget of ethanol in the global troposphere are briefly discussed. C1 CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. RP Leu, MT (reprint author), CALTECH, Jet Prop Lab, Div Earth & Space Sci, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 35 TC 7 Z9 7 U1 0 U2 3 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 JUN 1 PY 2006 VL 110 IS 21 BP 6660 EP 6666 DI 10.1021/jp055810h PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 046SO UT WOS:000237831500013 PM 16722680 ER PT J AU Michelsen, RR Staton, SJR Iraci, LT AF Michelsen, RR Staton, SJR Iraci, LT TI Uptake and dissolution of gaseous ethanol in sulfuric acid SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID UPPER TROPOSPHERE; SAO-PAULO; ACETONE; STRATOSPHERE; ALCOHOLS; DEEP; FORMALDEHYDE; SOLUBILITY; CHEMISTRY; EMISSIONS AB The solubility of gas-phase ethanol (ethyl alcohol, CH3CH2OH, EtOH) in aqueous sulfuric acid solutions was measured in a Knudsen cell reactor over ranges of temperature (209-237 K) and acid composition (39-76 wt % H2SO4). Ethanol is very soluble under these conditions: effective Henry's law coefficients, H*, range from 4 x 10(4) M atm(-1) in the 227 K, 39 wt % acid to greater than 10(7) M atm(-1) in the 76 wt % acid. In 76 wt % sulfuric acid, ethanol solubility exceeds that which can be precisely determined using the Knudsen cell technique but falls in the range of 10(7)-10(10) M atm(-1). The equilibrium concentration of ethanol in upper tropospheric/ lower stratospheric (UT/LS) sulfate particles is calculated from these measurements and compared to other small oxygenated organic compounds. Even if ethanol is a minor component in the gas phase, it may be a major constituent of the organic fraction in the particle phase. No evidence for the formation of ethyl hydrogen sulfate was found under our experimental conditions. While the protonation of ethanol does augment solubility at higher acidity, the primary reason H* increases with acidity is an increase in the solubility of molecular (i.e., neutral) ethanol. C1 NASA, Ames Res Ctr, Atmospher Chem & Dynam Branch, Moffett Field, CA 94035 USA. RP Iraci, LT (reprint author), NASA, Ames Res Ctr, Atmospher Chem & Dynam Branch, Moffett Field, CA 94035 USA. EM rmichelsen@rmc.edu; Laura.T.Iraci@nasa.gov NR 45 TC 14 Z9 14 U1 0 U2 8 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 JUN 1 PY 2006 VL 110 IS 21 BP 6711 EP 6717 DI 10.1021/jp056234s PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 046SO UT WOS:000237831500020 PM 16722687 ER PT J AU Christensen, LE Okumura, M Hansen, JC Sander, SP AF Christensen, LE Okumura, M Hansen, JC Sander, SP TI Experimental and ab initio study of the HO2 center dot CH3OH complex: Thermodynamics and kinetics of formation SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID PHASE SELF-REACTION; GAS-PHASE; TEMPERATURE-DEPENDENCE; HO2-H2O COMPLEX; HO2 RADICALS; WATER-VAPOR; H2O; NH3; ASSOCIATION; EXISTENCE AB Near-infrared spectroscopy was used to monitor HO2 formed by pulsed laser photolysis of Cl-2-O-2-CH3-OH- N-2 mixtures. On the microsecond time scale, [ HO2] exhibited a time dependence consistent with a mechanism in which [HO2] approached equilibrium via HO2 + CH3OH M reversible arrow M HO2 center dot CH3OH ( 3, - 3). The equilibrium constant for reaction 3, K-p, was measured between 231 and 261 K at 50 and 100 Torr, leading to standard reaction enthalpy and entropy values ( 1 sigma) of Delta rH(246K)degrees = - 37.4 +/- 4.8 kJ mol(-1) and Delta rS(246K)degrees = -100 +/- 19 J mol(-1) K-1. The effective bimolecular rate constant, k(3), for formation of the HO2, CH3OH complex is 2.8(-2.0)(+7.5.)10(-15.)exp[(1800 +/- (500)/T] cm(3) molecule(-1) s(-1) at 100 Torr ( 1 sigma). Ab initio calculations of the optimized structure and energetics of the HO2, CH3OH complex were performed at the CCSD(T)/6-311++G-(3df, 3pd)//MP2(full)/6-311++G(2df,2pd) level. The complex was found to have a strong hydrogen bond (De) 43.9 kJ mol(-1)) with the hydrogen in HO2 binding to the oxygen in CH3OH. The calculated enthalpy for association is Delta(r)H245K degrees = -36.8 kJ mol(-1). The potentials for the torsion about the O-2-H bond and for the hydrogen-bond stretch were computed and 1D vibrational levels determined. After explicitly accounting for these degrees of freedom, the calculated Third Law entropy of association is Delta rS(245K)degrees = -106 J mol(-1) K-1. Both the calculated enthalpy and entropy of association are in reasonably good agreement with experiment. When combined with results from our previous study (Christensen et al. Geophys. Res. Lett. 2002, 29; doi: 10.1029/2001GL014525), the rate coefficient for the reaction of HO2 with the complex, HO2 + HO2, CH3OH, is determined to be (2.1 +/- 0.7) x 10(-11) cm(3) molecule(-1) s(-1). The results of the present work argue for a reinterpretation of the recent measurement of the HO2 self-reaction rate constant by Stone and Rowley (Phys. Chem. Chem. Phys. 2005, 7, 2156). Significant complex concentrations are present at the high methanol concentrations used in that work and lead to a nonlinear methanol dependence of the apparent rate constant. This nonlinearity introduces substantial uncertainty in the extrapolation to zero methanol. C1 CALTECH, Arthur Amos Noyes Lab Chem Phys, Div Chem & Chem Phys, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Purdue Univ, Dept Chem, W Lafayette, IN 47906 USA. Purdue Univ, Dept Earth & Atmospher Sci, W Lafayette, IN 47906 USA. RP Okumura, M (reprint author), CALTECH, Arthur Amos Noyes Lab Chem Phys, Div Chem & Chem Phys, Pasadena, CA 91125 USA. EM mo@its.caltech.edu; Stanley.P.Sander@jpl.nasa.gov RI Okumura, Mitchio/I-3326-2013 OI Okumura, Mitchio/0000-0001-6874-1137 NR 34 TC 27 Z9 27 U1 2 U2 28 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 JUN 1 PY 2006 VL 110 IS 21 BP 6948 EP 6959 DI 10.1021/jp056579a PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 046SO UT WOS:000237831500042 PM 16722709 ER PT J AU Bryson, S Levy, D AF Bryson, S Levy, D TI On the total variation of high-order semi-discrete central schemes for conservation laws SO JOURNAL OF SCIENTIFIC COMPUTING LA English DT Article; Proceedings Paper CT 6th International Conference on Spectral and High Order Methods (ICOSAHOM) CY JUN 21-25, 2004 CL Brown Univ, Providence, RI HO Brown Univ DE high-order; central schemes; conservation laws; total variation ID ESSENTIALLY NONOSCILLATORY SCHEMES; CONVECTION-DIFFUSION EQUATIONS; TIME DISCRETIZATION METHODS; CENTRAL WENO SCHEMES; EFFICIENT IMPLEMENTATION; SYSTEMS AB We discuss a new fifth-order, semi-discrete, central-upwind scheme for solving one-dimensional systems of conservation laws. This scheme combines a fifth-order WENO reconstruction, a semi-discrete central-upwind numerical flux, and a strong stability preserving Runge-Kutta method. We test our method with various examples, and give particular attention to the evolution of the total variation of the approximations. C1 NASA, Ames Res Ctr, NASA Adv Supercomp Div, Moffett Field, CA 94035 USA. Stanford Univ, Dept Math, Stanford, CA 94305 USA. RP Bryson, S (reprint author), NASA, Ames Res Ctr, NASA Adv Supercomp Div, Moffett Field, Moffett Field, CA 94035 USA. EM bryson@nas.nasa.gov; dlevy@math.stanford.edu NR 20 TC 9 Z9 10 U1 0 U2 4 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0885-7474 J9 J SCI COMPUT JI J. Sci. Comput. PD JUN PY 2006 VL 27 IS 1-3 BP 163 EP 175 DI 10.1007/s10915-005-9046-8 PG 13 WC Mathematics, Applied SC Mathematics GA 051PI UT WOS:000238172600011 ER PT J AU Feng, HY Mavriplis, C Van der Wijngaart, R Biswas, R AF Feng, HY Mavriplis, C Van der Wijngaart, R Biswas, R TI Parallel 3D mortar element method for adaptive nonconforming meshes SO JOURNAL OF SCIENTIFIC COMPUTING LA English DT Article; Proceedings Paper CT 6th International Conference on Spectral and High Order Methods (ICOSAHOM) CY JUN 21-25, 2004 CL Brown Univ, Providence, RI HO Brown Univ DE mortar element method; spectral element method; adaptive; nonconforming ID FINITE-ELEMENT AB We present a new two-step "intermediate mortar" approach that efficiently extends the Mortar Element Method (MEM) to 3D meshes with nonconforming discretizations. The technique utilizes projection matrices derived in 2D, thereby avoiding the need to explicitly form large matrices for the 3D cases. The method also allows more flexibility for both h- and p-type adaptation. Parallel implementations with OpenMP and multithreading compiler directives are used to solve a moving heat source problem on SGI Origin and Cray MTA machines. Numerical results demonstrate the advantages of adaptive nonconforming meshes with MEM over uniformly fine meshes. C1 NASA, Ames Res Ctr, Comp Sci Corp, Moffett Field, CA 94035 USA. George Washington Univ, Dept Aerosp & Mech Engn, Washington, DC 20052 USA. NASA, Ames Res Ctr, NAS Div, Moffett Field, CA 94035 USA. RP Feng, HY (reprint author), NASA, Ames Res Ctr, Comp Sci Corp, Moffett Field, Moffett Field, CA 94035 USA. NR 14 TC 2 Z9 5 U1 0 U2 0 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0885-7474 J9 J SCI COMPUT JI J. Sci. Comput. PD JUN PY 2006 VL 27 IS 1-3 BP 231 EP 243 DI 10.1007/s10915-005-9026-z PG 13 WC Mathematics, Applied SC Mathematics GA 051PI UT WOS:000238172600016 ER PT J AU Yee, HC Sjogreen, B AF Yee, HC Sjogreen, B TI Non-linear filtering and limiting in high order methods for ideal and non-ideal MHD SO JOURNAL OF SCIENTIFIC COMPUTING LA English DT Article; Proceedings Paper CT 6th International Conference on Spectral and High Order Methods (ICOSAHOM) CY JUN 21-25, 2004 CL Brown Univ, Providence, RI HO Brown Univ DE high order schemes filtering; nonlinear filtering; limiting; MHD; shock-capturing; shock/turbulence interactions ID HYPERBOLIC CONSERVATION-LAWS; NAVIER-STOKES EQUATIONS; DIFFERENCE-METHODS; MAGNETOHYDRODYNAMICS; SCHEME AB The adaptive nonlinear filtering and limiting in spatially high order schemes (Yee et al. J. Comput. Phys. 150, 199 - 238, ( 1999), Sjogreen and Yee, J. Scient. Comput. 20, 211 - 255, ( 2004)) for the compressible Euler and Navier - Stokes equations have been recently extended to the ideal and non-ideal magnetohydrodynamics (MHD) equations, (Sjogreen and Yee, ( 2003), Proceedings of the 16th AIAA/CFD conference, June 23 - 26, Orlando F1; Yee and Sjogreen ( 2003), Proceedings of the International Conference on High Performance Scientific Computing, March, 10 - 14, Honai, Vietnam; Yee and Sjogreen ( 2003), RIACS Technical Report TR03. 10, July, NASA Ames Research Center; Yee and Sjogreen ( 2004), Proceedings of the ICCF03, July 12 - 16, Toronto, Canada). The numerical dissipation control in these adaptive filter schemes consists of automatic detection of different flow features as distinct sensors to signal the appropriate type and amount of numerical dissipation/filter where needed and leave the rest of the region free from numerical dissipation contamination. The numerical dissipation considered consists of high order linear dissipation for the suppression of high frequency oscillation and the nonlinear dissipative portion of high-resolution shock-capturing methods for discontinuity capturing. The applicable nonlinear dissipative portion of high-resolution shock-capturing methods is very general. The objective of this paper is to investigate the performance of three commonly used types of discontinuity capturing nonlinear numerical dissipation for both the ideal and non-ideal MHD. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Royal Inst Technol, S-10044 Stockholm, Sweden. RP Yee, HC (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 23 TC 4 Z9 4 U1 0 U2 1 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0885-7474 J9 J SCI COMPUT JI J. Sci. Comput. PD JUN PY 2006 VL 27 IS 1-3 BP 507 EP 521 DI 10.1007/s10915-005-9024-1 PG 15 WC Mathematics, Applied SC Mathematics GA 051PI UT WOS:000238172600036 ER PT J AU Lin, RQ Kuang, WJ AF Lin, RQ Kuang, WJ TI Nonlinear ship-wave interaction model, part 2: Ship boundary condition SO JOURNAL OF SHIP RESEARCH LA English DT Article ID NEUMANN-KELVIN PROBLEM; WATER AB One of the main problems in modeling ship-wave hydrodynamics is solving for the forcing (pressure) at the ship boundary. With an arbitrary ship, singularities occur in evaluating the velocity potential and the velocities on the hull. Inaccuracies in the evaluation of the singular terms in the velocity potential result in discretization errors, numerical errors, and excessive computational costs. In this paper we present a new approach to evaluating the pressure on a ship: evaluating the pressure in the ship normal vector coordinate system. The main advantage of this approach is that p is a smooth function in the ship normal vector coordinate system, enabling us to obtain accurate results very efficiently (i.e., with much less CPU time) without encountering numerical difficulties arising from possible singularities. C1 Naval Surface Warfare Ctr, Carderock Div, David Taylor Model Basin, Bethesda, MD USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Lin, RQ (reprint author), Naval Surface Warfare Ctr, Carderock Div, David Taylor Model Basin, Bethesda, MD USA. RI Kuang, Weijia/K-5141-2012 OI Kuang, Weijia/0000-0001-7786-6425 NR 15 TC 12 Z9 12 U1 0 U2 0 PU SOC NAVAL ARCH MARINE ENG PI JERSEY CITY PA 601 PAVONIA AVENUE, JERSEY CITY, NJ 07306 USA SN 0022-4502 J9 J SHIP RES JI J. Ship Res. PD JUN PY 2006 VL 50 IS 2 BP 181 EP 186 PG 6 WC Engineering, Marine; Engineering, Civil SC Engineering GA 050DK UT WOS:000238067500007 ER PT J AU Yang, Q Seo, JT Tabibi, B Ma, SM Jackson, A Skyles, T Wang, H Jung, SS Namkung, M AF Yang, Q Seo, JT Tabibi, B Ma, SM Jackson, A Skyles, T Wang, H Jung, SS Namkung, M TI Light-induced dispersion in noninstantaneous response nonlinear optical materials SO JOURNAL OF THE KOREAN PHYSICAL SOCIETY LA English DT Article; Proceedings Paper CT 4th International Conference on Advanced Materials and Devices/6th Symposium on the Nano-Technology and Plasma Application for Next Generation Processing CY DEC 05-07, 2005 CL Jeju, SOUTH KOREA DE light-induced dispersion; slow and fast light; superluminal propagation ID ELECTROMAGNETICALLY INDUCED TRANSPARENCY; ROOM-TEMPERATURE; PROPAGATION; REDUCTION; PULSE AB The light-induced dispersion in noninstantaneous response third-order nonlinear optical materials has been investigated in this work. We find, even far away from resonance, both normal and abnormal dispersions can be generated in third-order nonlinear optical materials, that possess large third-order nonlinearity and finite response time. The large third order nonlinearity and the finite response time are due to the highly dispersive coupling among the pump and the probe beams. This phenomenon may be used to control the group velocity of a light pulse. C1 Hampton Univ, Dept Phys, Hampton, VA 23668 USA. Nanjing Univ, Natl Lab Solid State Microstruct, Nanjing 210093, Peoples R China. Nanjing Univ, Dept Phys, Nanjing 210093, Peoples R China. Korea Rs Inst Stand & Sci, Taejon 305600, South Korea. NASA, Goddard Space Flight Ctr, Astrochem Lab, Greenbelt, MD 20771 USA. RP Yang, Q (reprint author), Hampton Univ, Dept Phys, Hampton, VA 23668 USA. EM jaetea.seo@hamptonu.edu RI Namkung, Min/E-1533-2012 NR 14 TC 0 Z9 0 U1 0 U2 2 PU KOREAN PHYSICAL SOC PI SEOUL PA 635-4, YUKSAM-DONG, KANGNAM-KU, SEOUL 135-703, SOUTH KOREA SN 0374-4884 J9 J KOREAN PHYS SOC JI J. Korean Phys. Soc. PD JUN PY 2006 VL 48 IS 6 BP 1264 EP 1267 PG 4 WC Physics, Multidisciplinary SC Physics GA 053RY UT WOS:000238324000018 ER PT J AU Ma, SM Seo, JT Yang, Q Battle, R Brown, H Lee, K Creekmore, L Jackson, A Skyles, T Tabibi, B Jung, SS Yu, W Namkung, M AF Ma, S. M. Seo, J. T. Yang, Q. Battle, R. Brown, H. Lee, K. Creekmore, L. Jackson, A. Skyles, T. Tabibi, B. Jung, S. S. Yu, W. Namkung, M. TI Third-order nonlinear susceptibility and hyperpolarizability of CdSe nanocrystals with femtosecond excitation SO JOURNAL OF THE KOREAN PHYSICAL SOCIETY LA English DT Article; Proceedings Paper CT 4th International Conference on Advanced Materials and Devices/6th Symposium on the Nano-Technology and Plasma Application for Next Generation Processing CY DEC 05-07, 2005 CL Cheju, SOUTH KOREA DE quantum dot; ultrafast nonlinear susceptibility; hyperpolarizability ID Z-SCAN; OPTICAL NONLINEARITY; SINGLE-BEAM; GLASSES AB Single beam femtosecond Z-scan spectroscopy at 775 nm revealed that the effective third-order nonlinear susceptibility and hyperpolarizability of CdSe colloidal nanocrystals near the Bohr radius were similar to 0.7 - 1.0 x 10(-22) m(2)/V-2 and similar to 0.18 - 2.0 x 10(-44) m(5)/V-2, respectively. The non-resonant nonlinearity increase for CdSe colloidal quantum dots withbigger than average diameters is attributed to their absorption cross-section being larger and their bandgap energy being narrower than those of the quantum dots with smaller sizes. C1 Hampton Univ, Dept Phys, Hampton, VA 23668 USA. Korea Res Inst Stand & Sci, Taejon 305600, South Korea. Rice Univ, Dept Chem, Houston, TX 77005 USA. NASA, Goddard Space Flight Ctr, Astrochem Lab, Greenbelt, MD 20771 USA. RP Ma, SM (reprint author), Hampton Univ, Dept Phys, Hampton, VA 23668 USA. EM jaetae.seo@hamptonu.edu RI Namkung, Min/E-1533-2012 NR 16 TC 11 Z9 11 U1 0 U2 1 PU KOREAN PHYSICAL SOC PI SEOUL PA 635-4, YUKSAM-DONG, KANGNAM-KU, SEOUL 135-703, SOUTH KOREA SN 0374-4884 EI 1976-8524 J9 J KOREAN PHYS SOC JI J. Korean Phys. Soc. PD JUN PY 2006 VL 48 IS 6 BP 1379 EP 1384 PG 6 WC Physics, Multidisciplinary SC Physics GA 053RY UT WOS:000238324000043 ER PT J AU Seo, JT Ma, SM Yang, Q Creekmore, L Brown, H Battle, R Lee, K Jackson, A Skyles, T Tabibi, B Yoo, KP Kim, SY Jung, SS Namkung, M AF Seo, JT Ma, SM Yang, Q Creekmore, L Brown, H Battle, R Lee, K Jackson, A Skyles, T Tabibi, B Yoo, KP Kim, SY Jung, SS Namkung, M TI Large optical nonlinearity of highly porous silica nanoaerogels in the nanosecond time domain SO JOURNAL OF THE KOREAN PHYSICAL SOCIETY LA English DT Article; Proceedings Paper CT 4th International Conference on Advanced Materials and Devices/6th Symposium on the Nano-Technology and Plasma Application for Next Generation Processing CY DEC 05-07, 2005 CL Jeju, SOUTH KOREA DE silica nanoaerogels; third-order nonlinear susceptibility; nonlinear transmittance limiting ID AEROGEL AB The nonlinear optical properties of highly porous silica nanoaerogels with a similar to 0.1 g/cm(3) apparent density were investigated using a spatially Gaussian shaped, similar to 8 ns pulsed laser operating at a wavelength of similar to 532 nm with a repetition rate of 10 Hz. Closed Z-scan spectroscopy revealed the negative nonlinearity (or defocusing effect) of the silica nanoaerogels. The third-order nonlinear susceptibility of silica nanoaerogels was estimated to be similar to 9.6 x 10(-19) m(2)/V-2 (similar to 6.9 x 10(-11) esu) from degenerate four-wave mixing measurements. The nonlinear transmittance limiting threshold of silica nanoaerogels was similar to 17 MW/cm(2). C1 Hampton Univ, Dept Phys, Hampton, VA 23668 USA. Sogang Univ, Dept Chem Engn, Seoul 121742, South Korea. Korea Res Inst Stand & Sci, Taejon 305600, South Korea. NASA, Goddard Space Flight Ctr, Astrochem Lab, Greenbelt, MD 20771 USA. RP Seo, JT (reprint author), Hampton Univ, Dept Phys, Hampton, VA 23668 USA. EM jaetae.seo@hamptonu.edu RI Namkung, Min/E-1533-2012 NR 11 TC 7 Z9 7 U1 0 U2 2 PU KOREAN PHYSICAL SOC PI SEOUL PA 635-4, YUKSAM-DONG, KANGNAM-KU, SEOUL 135-703, SOUTH KOREA SN 0374-4884 J9 J KOREAN PHYS SOC JI J. Korean Phys. Soc. PD JUN PY 2006 VL 48 IS 6 BP 1395 EP 1399 PG 5 WC Physics, Multidisciplinary SC Physics GA 053RY UT WOS:000238324000046 ER PT J AU Sodano, HA Bae, JS Inman, DJ Belvin, WK AF Sodano, HA Bae, JS Inman, DJ Belvin, WK TI Improved concept and model of current damper SO JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME LA English DT Article DE eddy current damper; magnetic damping; passive vibration suppression; viscous damping ID VIBRATION CONTROL-SYSTEM; ELECTROMAGNETIC FORCES; MAGNETIC BRAKING; BEAM AB When a conductive material experiences a time-varying magnetic field, eddy currents are generated in the conductor These eddy currents circulate such that they generate a magnetic field of their own, however the field generated is of opposite polarity, causing a repulsive force. The time-varying magnetic field needed to produce such currents can be induced either by movement of the conductor in the field or by changing the strength or position of the source of the magnetic field. In the case of a dynamic system the conductor is moving relative to the magnetic source, thus generating eddy currents that will dissipate into heat due to the resistivity of the conductor This process of the generation and dissipation of eddy current causes the system to function as a viscous damper In a, previous study, the concept and theoretical model was developed for one eddy current damping system that was shown to be effective in the suppression of transverse beam vibrations. The mathematical model developed to predict the amount of damping induced on the structure was shown to be accurate when the magnet was far from the beam but. was less accurate for the case that the gap between the magnet and beam was small. In, the present study, an improved theoretical model of the previously developed system will be formulated using the image method, thus allowing the eddy current density to be more, accurately computed. In addition to the development of an improved model, an improved concept of the eddy current damper configuration is developed, modeled, and tested. The, new damper configuration adds significantly more damping to the structure than the previously implemented design and has the capability to critically damp the beam's first bending mode. The eddy current damper is a noncontacting system, thus allowing it to be easily applied and able to add significant damping to the structure without changing. dynamic response. Furthermore, the previous model and the improved model will be applied to the new damper design and the enhanced accuracy of this new theoretical model will be proven. C1 Michigan Technol Univ, Dept Mech Engn, Houghton, MI 49931 USA. Korea Inst Energy Res, Wind Power Fluid Machinery Res Ctr, Dept New & Renewable Energy Res, Taejon, South Korea. Virginia Polytech Inst & State Univ, Ctr Intelligent Mat Syst & Struct, Blacksburg, VA 24061 USA. NASA, Langley Res Ctr, Struct Dynam Branch, Hampton, VA 23681 USA. RP Sodano, HA (reprint author), Michigan Technol Univ, Dept Mech Engn, 1400 Townsend Dr, Houghton, MI 49931 USA. EM hsodano@mtu.edu; jsbae@kierre.kr; dinman@vt.edu; w.k.belvin@larc.gov NR 24 TC 36 Z9 39 U1 2 U2 16 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 JUN PY 2006 VL 128 IS 3 BP 294 EP 302 DI 10.1115/1.2172256 PG 9 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 050QC UT WOS:000238102000003 ER PT J AU Sodano, HA Inman, DJ Belvin, WK AF Sodano, HA Inman, DJ Belvin, WK TI Development of a new passive-active magnetic damper for vibration suppression SO JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME LA English DT Article ID BRAKING; SYSTEM AB Magnetic fields can be used to apply damping to a vibrating structure. Dampers of this type function through the eddy currents that are generated in a conductive material experiencing a time-changing magnetic field. The density of these currents is directly related to the velocity of the change in magnetic field. However following the generation of these currents, the internal resistance of the conductor causes them to dissipate into heat. Because a portion of the moving conductor's kinetic energy is used to generate the eddy currents, which are then dissipated, a damping effect occurs. This damping force can be described as a viscous force due to the dependence on the velocity of the conductor In a previous study, a permanent magnet was fixed in a location such that the poling axis was perpendicular to the beam's motion and the radial magnetic flux was used to passively suppress the beam's vibration. Using this passive damping concept and the idea that the damping force is directly related to the velocity of the conductor a new passive-active damping mechanism will be created. This new damper will function by allowing the position of the magnet to change relative to the beam and thus allow the net velocity between the two to be maximized and thus the damping force significantly increased. Using this concept, a model of both the passive and active portion of the system will be developed, allowing the beams response to be simulated. To verify the accuracy of this model, experiments will be performed that demonstrate both the accuracy of the model and the effectiveness of this passive-active control system for use in suppressing the transverse vibration of a structure. C1 Michigan Technol Univ, Dept Mech Engn, Houghton, MI 49931 USA. Virginia Polytech Inst & State Univ, Ctr Intelligent Mat Syst & Struct, Blacksburg, VA 24061 USA. NASA, Langley Res Ctr, Struct Dynam Branch, Hampton, VA 23681 USA. RP Sodano, HA (reprint author), Michigan Technol Univ, Dept Mech Engn, 1400 Townsend Dr, Houghton, MI 49931 USA. EM hsodano@mtu.edu; dinman@vt.edu; w.k.belvin@larc.gov NR 18 TC 8 Z9 10 U1 2 U2 8 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 JUN PY 2006 VL 128 IS 3 BP 318 EP 327 DI 10.1115/1.2172258 PG 10 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 050QC UT WOS:000238102000005 ER PT J AU Zieg, MJ Lofgren, GE AF Zieg, MJ Lofgren, GE TI An experimental investigation of texture evolution during continuous cooling SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article DE crystal size distributions; experimental petrology; kinetics; chondrules ID CRYSTAL SIZE DISTRIBUTIONS; DYNAMIC CRYSTALLIZATION; DISTRIBUTION CSD; CHONDRULE MELTS; DIABASE DIKES; KINETICS; GROWTH; OLIVINE; NUCLEATION; SYSTEM AB Textural evolution during a controlled cooling experiment has been quantified using bulk textural characterizations (mean crystal length, total numbers of crystals and modal olivine content) and crystal size distributions (CSDs). The experiments involved subliquidus melting of an olivine-glass mixture followed by cooling at a constant rate (92 degrees C h(-1)) through the crystallization interval. Measured changes in population density, n(L), for small (< 0.3 mm) euhedral olivine crystals are shown to be consistent with a uniform crystal growth rate of 6.0 x 10(-7) Mm s(-1). The CSD trends for larger (> 0.3 mm) skeletal crystals are broadly consistent with an exponentially increasing nucleation rate and with a uniform growth rate of 2.0 x 10(-5) mm s(-1). However, the textural development of these crystals cannot be explained solely in terms of homogeneous nucleation and growth. Additional factors influencing the development of textures in the skeletal zone of the charges include grain impingement and development of skeletal overgrowths on the top of a layer of seed crystals. CSD data is ideal for analyzing texture development because it is sensitive to the detailed structure of the crystal population and can be used to detect variations in behavior between different size classes. Here, population density trends for various crystal size classes are used as a tool for estimating the kinetics of crystal growth and nucleation in a cooling igneous system. This type of analysis can be used to gain insight into crystallization processes from CSDs without relying on assumptions regarding CSD shape. Examples of the use of population density trends in the evaluation of natural systems are provided for the case of crystallization in porphyritic olivine chondrules and in komatiite flows. Published by Elsevier B.V. C1 NASA, Johnson Space Ctr, Houston, TX 77058 USA. RP Zieg, MJ (reprint author), Slippery Rock Univ, Dept Geog, 1 Morrow Way, Slippery Rock, PA 16057 USA. EM michael.zieg@sru.edu NR 38 TC 26 Z9 27 U1 2 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD JUN 1 PY 2006 VL 154 IS 1-2 BP 74 EP 88 DI 10.1016/j.jvolgeores.2005.09.020 PG 15 WC Geosciences, Multidisciplinary SC Geology GA 055QY UT WOS:000238466600008 ER PT J AU Dixon, TH Pivirotto, TJ Chapman, RF Tyce, RC AF Dixon, Timothy H. Pivirotto, Thomas J. Chapman, Robert F. Tyce, Robert C. TI A range-gated laser system for ocean floor imaging (Reprinted from Marine Technology Society Journal, vol 17, 1983) SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Reprint ID COPPER-VAPOR LASER; CHLORIDE; LASANT AB We describe tank studies which show that a copper chloride laser is a good illumination source for a deep ocean imaging system. The laser is naturally pulsed (similar to 20 ns pulse width) at repetition rates of 10 to 20 kHz, and operates with high (1%) efficiency in the blue-green window for optimum transmission in water. A range-gated, scanning imaging system based on this laser can operate with input power of a few hundred watts, obtaining 100m wide digital image coverage of the sea floor from altitudes of 50m. Measurements of range (bathymetry) and particulate matter distribution within the water column are also possible. C1 Jet Propuls Lab, Pasadena, CA USA. Scripps Inst Oceanog, Marine Phys Lab, La Jolla, CA USA. Univ Rhode Isl, Grad Sch Oceanog, Naragansett, RI USA. RP Dixon, TH (reprint author), Jet Propuls Lab, Pasadena, CA USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU MARINE TECHNOLOGY SOC INC PI COLUMBIA PA 5565 STERRETT PLACE, STE 108, COLUMBIA, MD 21044 USA SN 0025-3324 J9 MAR TECHNOL SOC J JI Mar. Technol. Soc. J. PD SUM PY 2006 VL 40 IS 2 BP 126 EP 133 PG 8 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 080VY UT WOS:000240277800022 ER PT J AU Luo, H Lu, H Leventis, N AF Luo, H. Lu, H. Leventis, N. TI The compressive behavior of isocyanate-crosslinked silica aerogel at high strain rates SO MECHANICS OF TIME-DEPENDENT MATERIALS LA English DT Article DE aerogel; crosslinked silica aerogel; nano-porous materials; nanofoam; split Hopkinson pressure bar; dynamic failure; high speed photography; digital image correlation ID DIGITAL-IMAGE-CORRELATION; HOPKINSON PRESSURE BAR; PULSE SHAPING TECHNIQUES; DEFORMATION MEASUREMENTS; MECHANICAL-PROPERTIES; DAMAGED CERAMICS; INTACT; CHEMISTRY; RESPONSES; TESTS AB Aerogels are low-density, highly nano-porous materials. Their engineering applications are limited due to their brittleness and hydrophilicity. Recently, a strong lightweight crosslinked silica aerogel has been developed by encapsulating the skeletal framework of amine-modified silica aerogels with polyureas derived by isocyanate. The mesoporous structure of the underlying silica framework is preserved through conformal polymer coating, and the thermal conductivity remains low. Characterization has been conducted on the thermal, physical properties and the mechanical properties under quasi-static loading conditions. In this paper, we present results on the dynamic compressive behavior of the crosslinked silica aerogel (CSA) using a split Hopkinson pressure bar (SHPB). A new tubing pulse shaper was employed to help reach the dynamic stress equilibrium and constant strain rate. The stress-strain relationship was determined at high strain rates within 114 - 4386 s(-1). The effects of strain rate, density, specimen thickness and water absorption on the dynamic behavior of the CSA were investigated through a series of dynamic experiments. The Young's moduli (or 0.2% offset compressive yield strengths) at a strain rate similar to 350 s(-1) were determined as 10.96/2.08, 159.5/6.75, 192.2/7.68, 304.6/11.46, 407.0/20.91 and 640.5/30.47 MPa for CSA with densities 0.205, 0.454, 0.492, 0.551, 0.628 and 0.731 g cm(-3), respectively. The deformation and failure behaviors of a native silica aerogel with density (0.472 g cm(-3)), approximately the same as a typical CSA sample were observed with a high speed digital camera. Digital image correlation technique was used to determine the surface strains through a series of images acquired using high speed photography. The relative uniform axial deformation indicated that localized compaction did not occur at a compressive strain level of similar to 17%, suggesting most likely failure mechanism at high strain rate to be different from that under quasi-static loading condition. The Poisson's ratio was determined to be 0.162 in nonlinear regime under high strain rates. CSA samples failed generally by splitting, but were much more ductile than native silica aerogels. C1 Oklahoma State Univ, Sch Mech & Aerosp Engn, Stillwater, OK 74078 USA. NASA, Gleen Res Ctr, Div Polymers Branch, Cleveland, OH 44135 USA. Univ Missouri Rolla, Dept Chem, Rolla, MO 65409 USA. RP Lu, H (reprint author), Oklahoma State Univ, Sch Mech & Aerosp Engn, Stillwater, OK 74078 USA. EM hongbin@ceat.okstate.edu; leventis@umr.edu RI Lu, Hongbing/A-1312-2011 NR 40 TC 36 Z9 37 U1 4 U2 54 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1385-2000 J9 MECH TIME-DEPEND MAT JI Mech. Time-Depend. Mater. PD JUN PY 2006 VL 10 IS 2 BP 83 EP 111 DI 10.1007/s11043-006-9015-0 PG 29 WC Mechanics; Materials Science, Characterization & Testing SC Mechanics; Materials Science GA 094ST UT WOS:000241260000001 ER PT J AU Glavin, DP Dworkin, JP Aubrey, A Botta, O Doty, JH Martins, Z Bada, JL AF Glavin, Daniel P. Dworkin, Jason P. Aubrey, Andrew Botta, Oliver Doty, James H., III Martins, Zita Bada, Jeffrey L. TI Amino acid analyses of Antarctic CM2 meteorites using liquid chromatography-time of flight-mass spectrometry SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID L-CYSTEINE REAGENTS; MURCHISON METEORITE; CARBONACEOUS CHONDRITE; O-PHTHALDIALDEHYDE/3-MERCAPTOPROPIONIC ACID; ELECTROSPRAY-IONIZATION; ORTHO-PHTHALALDEHYDE; EXOGENOUS DELIVERY; O-PHTHALDIALDEHYDE; PRIMITIVE EARTH; ALKANOIC ACIDS AB Amino acid analyses of the Antarctic CM2 chondrites Allan Hills (ALH) 83100 and Lewis Cliff (LEW) 90500 using liquid chromatography-time of flight-mass spectrometry (LC-ToF-MS) Coupled with UV fluorescence detection revealed that these carbonaceous meteorites contain a suite of indigenous amino acids not present in Antarctic ice. Several amino acids were detected in ALH 83100, including glycine, alanine, beta-alanine, gamma-amino-n-butyric acid (gamma-ABA), and alpha-aminoisobutyric acid (AIB) with concentrations ranging from 250 to 340 parts per billion (ppb). In contrast to ALH 83 100, the CM2 meteorites LEW 90500 and Murchison had a much higher total abundance of these amino acids (440-3200 ppb). In addition, ALL! 83 100 was found to have lower abundances of the alpha-dialkyl amino acids AIB and isovaline than LEW 90500 and Murchison. There are three possible explanations for the depleted amino, acid content in ALH 83100: 1) amino acid leaching from ALH 83100 during exposure to Antarctic ice meltwater, 2) a higher degree of aqueous alteration on the ALH 83 100 parent body, or 3) ALH 83 100 originated on a chemically distinct parent body from the other two CM2 meteorites. The high relative abundance of epsilon-amino-n-caproic acid (EACA) in the ALH 83100 meteorite as well as the Antarctic ice indicates that Nylon-6 contamination from the Antarctic sample storage bags may have occurred during collection. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Dematha Catholic High Sch, Hyattsville, MD 20781 USA. Leiden Inst Chem, NL-2300 RA Leiden, Netherlands. RP Glavin, DP (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM daniel.p.glavin@nasa.gov RI Glavin, Daniel/D-6194-2012; Martins, Zita/H-4860-2015; Dworkin, Jason/C-9417-2012 OI Glavin, Daniel/0000-0001-7779-7765; Martins, Zita/0000-0002-5420-1081; Dworkin, Jason/0000-0002-3961-8997 NR 62 TC 76 Z9 76 U1 1 U2 21 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUN PY 2006 VL 41 IS 6 BP 889 EP 902 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 051TN UT WOS:000238184000006 ER PT J AU Bentrup, KHZ Ramamurthy, R Ott, CM Emami, K Nelman-Gonzalez, M Wilson, JW Richter, EG Goodwin, TJ Alexander, JS Pierson, DL Pellis, N Buchanan, KL Nickerson, CA AF Bentrup, Kerstin Honer zu Ramamurthy, Rajee Ott, C. Mark Emami, Kamal Nelman-Gonzalez, Mayra. Wilson, James W. Richter, Emily G. Goodwin, Thomas J. Alexander, J. Stephen Pierson, Duane L. Pellis, Neal Buchanan, Kent L. Nickerson, Cheryl A. TI Three-dimensional organotypic models of human colonic epithelium to study the early stages of enteric salmonellosis SO MICROBES AND INFECTION LA English DT Article DE 3-D cell culture; HT-29; Salmonella typhimurium; SPI-1; organotypic model ID ROTATING-WALL VESSEL; INDUCED INTERLEUKIN-8 SECRETION; TISSUE-CULTURE MODEL; CARCINOMA CELL-LINE; GENE-EXPRESSION; ESCHERICHIA-COLI; SIMULATED MICROGRAVITY; SEROVAR TYPHIMURIUM; MOLECULAR-BASIS; DIFFERENTIATION AB In vitro cell culture models used to study how Salmonella initiates disease at the intestinal epithelium would benefit from the recognition that organs and tissues function in a three-dimensional (3-D) environment and that this spatial context is necessary for development of cultures that more realistically resemble in vivo tissues/organs. Our aim was to establish and characterize biologically meaningful 3-D models of human colonic epithelium and apply them to study the early stages of enteric salmonellosis. The human colonic cell line HT-29 was cultured in 3-D and characterized by immumohistochemistry, histology, and scanning electron microscopy. Wild-type Salmonella typhimurium and an isogenic SPI-I type three secretion system (TTSS) mutant derivative (invA) were used to compare the interactions with 3-D cells and monolayers in adherence/invasion, tissue pathology, and cytokine expression studies. The results showed that 3-D culture enhanced many characteristics normally associated with fully differentiated, functional intestinal epithelia in vivo, including better organization of junctional, extracellular matrix, and brush-border proteins, and highly localized mucin production. Wild-type Salmonella demonstrated increased adherence, but significantly lower invasion for 3-D cells. Interestingly, the SPI-I TTSS mutant showed wild-type ability to invade into the 3-D cells but did not cause significant structural changes to these cells. Moreover, 3-D cells produced less interleukin-8 before and after Salmonella infection. These results suggest that 3-D cultures of human colonic epithelium provide valuable alternative models to study human enteric salmonellosis with potential for novel insight into Salmonella pathogenesis. (c) 2006 Elsevier SAS. All rights reserved. C1 Tulane Univ, Hlth Sci Ctr, Dept Microbiol & Immunol, Program Mol Pathogenesis & Immun, New Orleans, LA 70112 USA. Tulane Univ, Hlth Sci Ctr, Tulane Ctr Excellence Bioengn, Program Mol Pathogenesis & Immun, New Orleans, LA 70112 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Louisiana State Univ, Hlth Sci Ctr, Dept Mol & Cellular Physiol, Shreveport, LA 71130 USA. RP Nickerson, CA (reprint author), Arizona State Univ, Biodesign Inst, Ctr Infect Dis & Vaccinol, POB 875401, Tempe, AZ 85287 USA. EM cheryl.nickerson@asu.edu NR 65 TC 38 Z9 38 U1 4 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1286-4579 J9 MICROBES INFECT JI Microbes Infect. PD JUN PY 2006 VL 8 IS 7 BP 1813 EP 1825 DI 10.1016/j.micinf.2006.02.020 PG 13 WC Immunology; Infectious Diseases; Microbiology SC Immunology; Infectious Diseases; Microbiology GA 079CS UT WOS:000240153700019 ER PT J AU Reber, AC Clayborne, PA Reveles, JU Khanna, SN Castleman, AW Ali, A AF Reber, AC Clayborne, PA Reveles, JU Khanna, SN Castleman, AW Ali, A TI Silicon oxide nanoparticles reveal the origin of silicate grains in circumstellar environments SO NANO LETTERS LA English DT Article ID CLUSTERS; NUCLEATION; CONDENSATION; OPTIMIZATION; POTENTIALS; EMISSION; STARS; DUST; SIO2 AB A synergistic effort combining experiments in beams and first principles theoretical investigations is used to propose mechanisms that could lead to the formation of silicates and nanoparticles with silicon-rich cores through agglomeration of SiO, an abundant oxygen-bearing species in space. The silicon oxygen species involved in the transformation have optical excitations that could contribute to extended red emissions and blue luminescence. Apart from resolving an outstanding astronomical problem, we demonstrate novel silicon architectures. C1 Virginia Commonwealth Univ, Dept Phys, Richmond, VA 23284 USA. Penn State Univ, Dept Chem, University Pk, PA 16802 USA. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Astrochem Lab, Greenbelt, MD 20771 USA. RP Khanna, SN (reprint author), Virginia Commonwealth Univ, Dept Phys, Richmond, VA 23284 USA. EM snkhanna@vcu.edu RI Reber, Arthur/A-3698-2009; Reveles, J Ulises/B-2655-2009; Clayborne, Andre/E-4881-2010 OI Reber, Arthur/0000-0003-1013-331X; Clayborne, Andre/0000-0002-0574-0847 NR 29 TC 24 Z9 24 U1 0 U2 2 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 JUN PY 2006 VL 6 IS 6 BP 1190 EP 1195 DI 10.1021/nl0605521 PG 6 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 052UB UT WOS:000238258300022 PM 16771578 ER PT J AU Heap, SR Lindler, DJ Woodgate, B AF Heap, Sara R. Lindler, Don J. Woodgate, Bruce TI An integral-field spectrograph for the terrestrial planet finder coronagraph SO NEW ASTRONOMY REVIEWS LA English DT Article; Proceedings Paper CT Conference on Integral Field Spectroscopy CY JUL 04-08, 2005 CL Durham, ENGLAND DE integral-field spectroscopy; coronagraph; terrestrial planet finder; exo-planets AB We describe the rationale and requirements for an integral-field spectrograph aboard NASA's Terrestrial Planet Finder Coronagraph. (c) 2006 Published by Elsevier B.V. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Heap, SR (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM sally.heap@nasa.gov RI heap, sara/E-2237-2012 NR 9 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 J9 NEW ASTRON REV JI New Astron. Rev. PD JUN PY 2006 VL 50 IS 4-5 BP 294 EP 296 DI 10.1016/j.newar.2006.03.013 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 061QT UT WOS:000238888200013 ER PT J AU Woodgate, B Mentzell, E Hilton, G Lindler, D AF Woodgate, Bruce Mentzell, Eric Hilton, George Lindler, Don TI An integral field spectrograph design concept for the terrestrial planet finder coronagraph SO NEW ASTRONOMY REVIEWS LA English DT Article; Proceedings Paper CT Conference on Integral Field Spectroscopy CY JUL 04-08, 2005 CL Durham, ENGLAND AB An integral field spectrograph following the TPF coronagraph can provide the required spectral resolving power R similar to 70 with spatial resolution at the telescope diffraction limit, and covering the coronagraphic dark hole. This allows spectra to be obtained of all planets around the star simultaneously, spectra of disks, measurement of residual speckles for subtraction, and insensitivity to roll control and alignment. Short spectra and the many spatial elements required are most easily implemented using a microlens array at the entrance to a prism spectrograph. To minimize the size of the special photon-counting CCD detectors required, a high filling factor of detector pixel usage is desired. This can be accomplished by using a crossed cylindrical microlens array to create virtual slits at the focus of each lenslet. The lenslets must be illuminated by a highly asymmetric image scale, for which we use cylindrical mirrors to magnify the image in one direction while de-magnifying in the orthogonal direction. (c) 2006 Elsevier B.V. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Woodgate, B (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM bruce.e.woodgate@nasa.gov NR 3 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 J9 NEW ASTRON REV JI New Astron. Rev. PD JUN PY 2006 VL 50 IS 4-5 BP 297 EP 300 DI 10.1016/j.newar.2006.03.010 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 061QT UT WOS:000238888200014 ER PT J AU Cardoso, MR Neves, UM Misoguti, L Ye, ZH Bu, XR Mendonca, CR AF Cardoso, M. R. Neves, U. M. Misoguti, L. Ye, Zhihong Bu, Xiu R. Mendonca, C. R. TI One- and two-photon induced birefringence in Salen dye cast films SO OPTICAL MATERIALS LA English DT Article DE azopolymers; birefringence; optical storage; two-photon absorption ID BLODGETT LB FILMS; REVERSIBLE OPTICAL STORAGE; AZO POLYMERS; CADMIUM STEARATE; PHOTOINDUCED BIREFRINGENCE; AZOAROMATIC COMPOUNDS; AMORPHOUS POLYMERS; DISPERSE RED-19; SIDE-GROUPS; FEMTOSECOND AB In this paper, we present the one- and two-photon optically induced birefringence in cast films of amorphous poly(methyl methacrylate) (PMMA), containing a new series of organometallic azoaromatic compounds, referred to as Salen dyes, which may be used in optical storage applications. For the one-photon optically induced birefringence, longer writing times were required for the organometallic compounds in comparison with the nonmetal one, probably due to the higher degree of aggregation in the azoaromatic moieties that precludes molecular orientation. Furthermore, as a novelty concerning optical storage, two-photon optically induced birefringence could be achieved in the Salen dyes guest-host films, which allows their application in three-dimensional optical memories. (C) 2005 Elsevier B.V. All rights reserved. C1 Inst Fis Sao Carlos, Dept Fis & Ciencia Mat, BR-13560970 Sao Carlos, SP, Brazil. Clark Atlanta Univ, Dept Chem, Atlanta, GA 30314 USA. Clark Atlanta Univ, NASA, Ctr High Performance Polymers & Composites, Atlanta, GA 30314 USA. RP Mendonca, CR (reprint author), Inst Fis Sao Carlos, Dept Fis & Ciencia Mat, Caixa Postal 369, BR-13560970 Sao Carlos, SP, Brazil. EM crmendon@if.sc.usp.br RI Misoguti, Lino/C-2462-2012; Group, Photonics/D-3910-2012; Mendonca, Cleber/B-9050-2012; Cardoso, Marcos/I-4355-2013; Sao Carlos Institute of Physics, IFSC/USP/M-2664-2016 OI Misoguti, Lino/0000-0001-6624-8453; Cardoso, Marcos/0000-0001-6030-8566; NR 24 TC 9 Z9 9 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0925-3467 J9 OPT MATER JI Opt. Mater. PD JUN PY 2006 VL 28 IS 8-9 BP 1118 EP 1122 DI 10.1016/j.optmat.2005.06.014 PG 5 WC Materials Science, Multidisciplinary; Optics SC Materials Science; Optics GA 047HU UT WOS:000237871200041 ER PT J AU Hu, J Xin, XB Zhao, JH Yan, F Guan, B Seely, J Kjornrattanawanich, B AF Hu, J Xin, XB Zhao, JH Yan, F Guan, B Seely, J Kjornrattanawanich, B TI Highly sensitive visible-blind extreme ultraviolet Ni/4H-SiC Schottky photodiodes with large detection area SO OPTICS LETTERS LA English DT Article AB Ni/4H-SiC Schottky photodiodes of 5 mm X 5 mm area have been fabricated and characterized. The photodiodes show less than 0.1 pA dark current at -4 V and an ideality factor of 1.06. A quantum efficiency (QE) between 3 and 400 nm has been calibrated and compared with Si photodiodes optimized for extreme ultraviolet (EUV) detection. In the EUV region, the QE of SiC detectors increases from 0.14 electrons/photon at 120 nm to 30 electrons/photon at 3 nm. The mean energy of electron-hole pair generation of 4H-SiC estimated from the spectral QE is found to be 7.9 eV. (c) 2006 Optical Society of America. C1 Rutgers State Univ, Dept Elect & Comp Engn, SiCLAB, Piscataway, NJ 08854 USA. NASA, Goddard Space Flight Ctr, Detector Syst Branch, MEI Technol, Greenbelt, MD 20771 USA. USN, Res Lab, Div Space Sci, Washington, DC 20375 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Univ Space Res Assoc, Upton, NY 11973 USA. RP Hu, J (reprint author), Rutgers State Univ, Dept Elect & Comp Engn, SiCLAB, 94 Brett Rd, Piscataway, NJ 08854 USA. EM fyan@pop500.gsfc.nasa.gov NR 13 TC 23 Z9 26 U1 0 U2 5 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUN 1 PY 2006 VL 31 IS 11 BP 1591 EP 1593 DI 10.1364/OL.31.001591 PG 3 WC Optics SC Optics GA 045FO UT WOS:000237728200001 PM 16688230 ER PT J AU Hemmati, H Chen, YJ AF Hemmati, H Chen, YJ TI Active optical compensation of low-quality optical system aberrations SO OPTICS LETTERS LA English DT Article ID TELESCOPE; MIRROR AB We describe a method for the correction of slowly varying wavefront aberrations of low-quality telescope mirrors by using a DM in an active optical compensation system. Our goal is to reduce the surface wavefront error of low-cost multimeter-diameter mirrors from approximately 10 waves peak-to-valley (P-V), at a 1 mu m wavelength, to approximately I wave or less. In a proof-of-concept demonstration using a 0.3 m telescope at a wavelength of 633 nm, the rms wavefront error improved to 0.05 waves (0.26 waves P-V) from the original value of 1.4 waves rms (6.5 waves P-V). The Strehl ratio improved to 89% from the original value of 0.08%. The types of aberrations corrected include astigmatism, coma, defocus, trefoil, and higher-order aberrations. (c) 2006 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hemmati, H (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM hamid.hemmati@jpl.nasa.gov NR 8 TC 6 Z9 6 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUN 1 PY 2006 VL 31 IS 11 BP 1630 EP 1632 DI 10.1364/OL.31.001630 PG 3 WC Optics SC Optics GA 045FO UT WOS:000237728200014 PM 16688243 ER PT J AU Bivolaru, D Danehy, PM Lee, JW AF Bivolaru, D Danehy, PM Lee, JW TI Intracavity Rayleigh-Mie scattering for multipoint, two-component velocity measurement SO OPTICS LETTERS LA English DT Article AB A simultaneous multipoint, two-component Doppler velocimeter is described. The system uses two optical cavities: a Fabry-Perot etalon and an optical cavity for collecting and recirculating the Rayleigh-Mie-scattered light that is collected from the measurement volume in two parallel but opposite directions. Single-pulse measurements of two orthogonal components of the velocity vector in a supersonic free jet were performed to demonstrate the technique. The recirculation of the light rejected by the interferometer input mirror also increased the signal intensity by a factor of 3.5. (c) 2006 Optical Society of America. 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 Langlely Blvd, Hampton, VA 23681 USA. EM d.bivolaru@lare.nasa.gov NR 8 TC 3 Z9 4 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUN 1 PY 2006 VL 31 IS 11 BP 1645 EP 1647 DI 10.1364/OL.31.001645 PG 3 WC Optics SC Optics GA 045FO UT WOS:000237728200019 PM 16688248 ER PT J AU Des Marais, DJ AF Des Marais, David J. CA Athena Sci Team TI Astrobiology and the exploration of Gusev crater by the Mars Exploration Rover Spirit SO ORIGINS OF LIFE AND EVOLUTION OF THE BIOSPHERE LA English DT Meeting Abstract C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM David.J.DesMarais@nasa.gov NR 0 TC 0 Z9 0 U1 1 U2 5 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 JUN PY 2006 VL 36 IS 3 BP 226 EP 227 PG 2 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 075QD UT WOS:000239899400028 ER PT J AU Pohorille, A Schweighofer, K Wilson, MA AF Pohorille, Andrew Schweighofer, Karl Wilson, Michael A. TI The origin and early evolution of membrane proteins SO ORIGINS OF LIFE AND EVOLUTION OF THE BIOSPHERE LA English DT Meeting Abstract C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif San Francisco, Dept Pharmaceut Chem, San Francisco, CA 94143 USA. EM pohorill@max.arc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 1 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 JUN PY 2006 VL 36 IS 3 BP 236 EP 237 PG 2 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 075QD UT WOS:000239899400038 ER PT J AU Bahn, P Pravdo, S Rudis, M Pappelis, A AF Bahn, Peter Pravdo, Steven Rudis, Mark Pappelis, Aristotel TI Alkanes to diamonds: A speculation about Titan SO ORIGINS OF LIFE AND EVOLUTION OF THE BIOSPHERE LA English DT Meeting Abstract C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. So Illinois Univ, Carbondale, IL 62901 USA. EM pbahn@mvn.net; spravdo@jpl.nasa.gov; rudism@yahoo.com; aristote@siu.edu NR 0 TC 0 Z9 0 U1 0 U2 0 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 JUN PY 2006 VL 36 IS 3 BP 323 EP 324 PG 2 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 075QD UT WOS:000239899400118 ER PT J AU Soulakellis, NA Novak, ID Zouros, N Lowman, P Yates, J AF Soulakellis, NA Novak, ID Zouros, N Lowman, P Yates, J TI Fusing Landsat-5/TM imagery and shaded relief maps in tectonic and geomorphic mapping: Lesvos Island, Greece SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID ACTIVE TECTONICS AB The significance of both solar elevation angle and azimuth are critical elements for examining Earth observation datasets. Illumination angle is a crucial parameter affecting the appearance of the topographically related and dependent features, Therefore, an improved methodology of data fusion for tectonic and geomorphic mapping is needed to augment the traditional false color composite analysis. A long-standing problem in such applications is the bias introduced by illumination, geometry specifically sun elevation and azimuth. A Landsat-5 image of Lesvos Island, Greece, was combined with digital elevation models to produce fused images with a wide range of illumination azimuths and elevation in a GIS environment. Sixteen combinations of sun elevation angle (using 15 degrees and 30 degrees) paired with azimuth (0 degrees to 360 degrees at 45 degrees increments) were considered. This new technique compensates for local conditions such as generally cloudy winters which make it difficult to obtain images with low sun elevation or images of eroded landforms with subdued geomorphic expression. The resulting fused images combine the tonal information and high spatial resolution of Landsat with the strong topographic rendition of digital elevation models. Well-known faults, with more or less significant expression on the surface known from previous image interpretation and fieldwork, are more easily identifiable. Shaded relief maps produced by applying the lower illumination angle in combination with an azimuth perpendicular to the fault orientation produced the best results. Additionally, previously unknown linear and circular features, e.g., calderas, were represented in the low illumination angle image, independent of its azimuth. Fused images will be further combined with geologic and seismicity maps to study problems such as location of the Anatolian Plate's boundaries and their nature (sharp or diffuse). C1 Univ Aegean, Dept Geog, GR-81100 Mitilini, Greece. Univ So Maine, Dept Geol, Portland, ME 04103 USA. NASA, Goddard Space Flight Ctr, Geodynam Branch, Greenbelt, MD 20771 USA. RP Soulakellis, NA (reprint author), Univ Aegean, Dept Geog, Univ Hill, GR-81100 Mitilini, Greece. EM n.soulakellis@aegean.gr; novak@usm.maine.edu; zouros@aegean.gr; Paul.D.Lowman@nasa.gov; yates@core2.gsfc.nasa.gov NR 34 TC 7 Z9 7 U1 0 U2 4 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 USA SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD JUN PY 2006 VL 72 IS 6 BP 693 EP 700 PG 8 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 053VQ UT WOS:000238334400011 ER PT J AU Sudbrack, CK Noebe, RD Seidman, DN AF Sudbrack, CK Noebe, RD Seidman, DN TI Direct observations of nucleation in a nondilute multicomponent alloy SO PHYSICAL REVIEW B LA English DT Article ID 3-DIMENSIONAL ATOM-PROBE; MONTE-CARLO SIMULATIONS; MICROSCOPY; KINETICS AB The chemical pathways leading to gamma(')(L1(2)) nucleation from nondilute Ni-5.2 Al-14.2 Cr at. %, gamma(fcc), at 873 K are followed with radial distribution functions and isoconcentration surface analyses of direct-space atom-probe tomographic images. Although Cr atoms initially are randomly distributed, a distribution of congruent Ni3Al short-range-order domains (SRO), < R >congruent to 0.6 nm, results from Al diffusion during quenching. Domain site occupancy develops as their number density increases leading to Al-rich phase separation by gamma '-nucleation, < R >=0.75 nm, after SRO occurs. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Sudbrack, CK (reprint author), Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. EM csudbrack@alumni.reed.edu; d-seidman@northwestern.edu RI Seidman, David/B-6697-2009 NR 13 TC 38 Z9 38 U1 0 U2 8 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 JUN PY 2006 VL 73 IS 21 AR 212101 DI 10.1103/PhysRevB.73.212101 PG 4 WC Physics, Condensed Matter SC Physics GA 058WV UT WOS:000238696200001 ER PT J AU van Meter, JR Baker, JG Koppitz, M Choi, DI AF van Meter, James R. Baker, John G. Koppitz, Michael Choi, Dae-Il TI How to move a black hole without excision: Gauge conditions for the numerical evolution of a moving puncture SO PHYSICAL REVIEW D LA English DT Article ID GRAVITATIONAL-WAVES; RELATIVITY AB Recent demonstrations of unexcised black holes traversing across computational grids represent a significant advance in numerical relativity. Stable and accurate simulations of multiple orbits, and their radiated waves, result. This capability is critically undergirded by a careful choice of gauge. Here we present analytic considerations which suggest certain gauge choices, and numerically demonstrate their efficacy in evolving a single moving puncture black hole. C1 NASA, Goddard Space Flight Ctr, Gravitat Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. RP van Meter, JR (reprint author), NASA, Goddard Space Flight Ctr, Gravitat Astrophys Lab, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA. RI van meter, james/E-7893-2011 NR 21 TC 128 Z9 128 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1550-7998 J9 PHYS REV D JI Phys. Rev. D PD JUN PY 2006 VL 73 IS 12 AR 124011 DI 10.1103/PhysRevD.73.124011 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 058XW UT WOS:000238698900051 ER PT J AU Zhu, DM Zhou, WC Ray, CS Day, DE AF Zhu, Dongmei Zhou, Wancheng Ray, Chandra S. Day, Delbert E. TI Method for estimating continuous cooling transformation curves of glasses SO PHYSICS AND CHEMISTRY OF GLASSES-EUROPEAN JOURNAL OF GLASS SCIENCE AND TECHNOLOGY PART B LA English DT Article AB A method is proposed for estimating the critical cooling rate and continuous cooling transformation curve (CCT)from isothermal TTT data of glasses. The critical cooling rates and CCT curves for a group of lithium disilicate glasses containing different amounts of Pt as nucleating agent estimated through this method are compared with the experimentally measured values. By analysis of the experimental and calculated data of the lithium disilicate glasses, a simple relationship between the crystallised amount in the glasses during continuous cooling, X, and the temperature of undercooling, Delta T, was found to be X=AR(-4)exp(B Delta T), where Delta T is the temperature difference between the theoretical melting point of the glass composition and the temperature in discussion, R is the cooling rate, and A and B are constants. The relation between the amount of crystallisation during continuous cooling and isothermal hold can be expressed as (X-cT/X-iT)=(4/B)(4)Delta T-4. X-cT here stands for the crystallised amount in a glass during continuous cooling for a time t when the temperature comes to T, and X-iT for the crystallised amount during isothermal hold at temperature T for a time t. C1 Northwestern Polytech Univ, State Key Lab Solidificat Proc, Xian 710072, Shaanxi, Peoples R China. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Missouri, Ctr Mat Res, Rolla, MO 65409 USA. RP Zhu, DM (reprint author), Northwestern Polytech Univ, State Key Lab Solidificat Proc, Xian 710072, Shaanxi, Peoples R China. EM dzhunwpu@126.com NR 9 TC 3 Z9 3 U1 0 U2 4 PU SOC GLASS TECHNOLOGY PI SHEFFIELD PA UNIT 9, TWELVE O CLOCK COURT, 21 ATTERCLIFFE RD, SHEFFIELD S4 7WW, S YORKSHIRE, ENGLAND SN 0031-9090 J9 PHYS CHEM GLASSES-B JI Phys. Chem. Glasses-Eur. J. Glass Sci. Technol. Part B PD JUN PY 2006 VL 47 IS 3 BP 271 EP 277 PG 7 WC Chemistry, Physical; Materials Science, Ceramics SC Chemistry; Materials Science GA 083LQ UT WOS:000240457800003 ER PT J AU Pettersson-Reif, BA Gatski, TB Rumsey, CL AF Pettersson-Reif, BA Gatski, TB Rumsey, CL TI On the behavior of two-equation models in nonequilibrium homogeneous turbulence SO PHYSICS OF FLUIDS LA English DT Article ID FLOWS AB The class of turbulence models that utilize two-equation differential transport equations is investigated. A dynamical systems analysis is performed on these transport equations to identify the various critical points and associated stability characteristics. The goal is to understand the transient solution behavior and to identify the possible solution fixed points. The analysis is restricted to homogeneous flows with constant and time-dependent mean shear. The transient behavior of the turbulence variables identifies possible pseudolaminar solutions that can be generated. These solutions are unphysical and need to be avoided. The present study provides the necessary framework for analyzing such two-equation turbulence models. Finally it is shown that models rigorously derived from Reynolds-stress transport models by utilizing the algebraic stress approximation, e.g., explicit algebraic stress models, still constitute a justifiable method also when the mean shear varies in time, provided that the time variation is sufficiently slow. Closed form algebraic time dependent solutions are derived for some commonly used models in homogeneous shear flows. C1 Norwegian Def Res Estab, NO-2025 Kjeller, Norway. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Pettersson-Reif, BA (reprint author), Norwegian Def Res Estab, NO-2025 Kjeller, Norway. EM Bjorn.Reif@ffi.no NR 14 TC 3 Z9 3 U1 0 U2 1 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 JUN PY 2006 VL 18 IS 6 AR 065109 DI 10.1063/1.2213642 PG 15 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 059KK UT WOS:000238731500028 ER PT J AU Mikellides, IG Katz, I Goebel, DM Polk, JE Jameson, KK AF Mikellides, IG Katz, I Goebel, DM Polk, JE Jameson, KK TI Plasma processes inside dispenser hollow cathodes SO PHYSICS OF PLASMAS LA English DT Article ID MODEL AB A two-dimensional fluid model of the plasma and neutral gas inside dispenser orificed hollow cathodes has been developed to quantify plasma processes that ultimately determine the life of the porous emitters inserted in these devices. The model self-consistently accounts for electron emission from the insert as well as for electron and ion flux losses from the plasma. Two cathodes, which are distinctively different in size and operating conditions, have been simulated numerically. It is found that the larger cathode, with outer tube diameter of 1.5 cm and orifice diameter of 0.3 cm, establishes an effective emission zone that spans approximately the full length of the emitter when operated at a discharge current of 25 A and a flow rate of 5.5 sccm. The net heating of the emitter is caused by ions that are produced by ionization of the neutral gas inside the tube and are then accelerated by the sheath along the emitter. The smaller cathode, with an outer diameter of 0.635 cm and an orifice diameter of 0.1 cm, does not exhibit the same operational characteristics. At a flow rate of 4.25 sccm and discharge current of 12 A, the smaller cathode requires 4.5 times the current density near the orifice and operates with more than 6 times the neutral particle density compared to the large cathode. As a result, the plasma particle density is almost one order of magnitude higher compared to the large cathode. The plasma density in this small cathode is high enough such that the Debye length is sufficiently small to allow "sheath funneling" into the pores of the emitter. By accessing areas deeper into the insert material, it is postulated that the overall emission of electrons is significantly enhanced. The maximum emission current density is found to be about 1 A/mm(2) in the small cathode, which is about one order of magnitude higher than attained in the large cathode. The effective emission zone in the small cathode extends to about 15% of the emitter length only, and the power deposited at the emitter surface by returning electrons is found to be twice that deposited by ions. A previous study suggested that the computed particle flux and energy of ions to the emitter of the 1.5 cm cathode were not high enough to change the barium evaporation rate compared to thermally induced evaporation. The same suggestion is made here for the 0.635 cm cathode. The peak ion flux to the emitter is found to be 1.2 A/cm(2) (7.6x10(18)/s cm(2)), and the corresponding peak sheath drop is 2.9 V. Consequently, once the emitter operating temperature is known it is possible to determine directly the barium depletion-limited life of these cathodes using existing vacuum-cathode data. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mikellides, IG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Ioannis.G.Mikellides@jpl.nasa.gov NR 26 TC 10 Z9 10 U1 3 U2 17 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2006 VL 13 IS 6 AR 063504 DI 10.1063/1.2208292 PG 10 WC Physics, Fluids & Plasmas SC Physics GA 059KP UT WOS:000238732000064 ER PT J AU Hawkins, T Hall, L Tollison, K Brand, A Mckay, M Drakes, GW AF Hawkins, T Hall, L Tollison, K Brand, A Mckay, M Drakes, GW TI Synthesis and characterization of energetic 1,2-bis(oxyamino) ethane salts SO PROPELLANTS EXPLOSIVES PYROTECHNICS LA English DT Article DE oxyamine; nitrates; perchlorates; X-ray structures ID TEMPERATURE IONIC LIQUIDS; ALKALI-METAL NITRATES; MOLECULAR STRUCTURE; VIBRATIONAL SPECTRA; DINITRAMIDE ANION; CRYSTAL-STRUCTURE; INFRARED SPECTRA; RAMAN-SPECTRA; GAS-PHASE; PERCHLORATE AB The synthesis, characterization, theoretical calculations, and safety studies of energetic salts based on 1,2-bis(oxyamino)ethane, (H2N-O-CH2-CH2-O-NH2), were carried out. The salts were characterized by vibrational (infrared, Raman), multinuclear NMR studies (H-1, C-13), differential scanning calorimetry (DSC), elemental analysis, and initial safety testing (impact and friction sensitivity). Single crystal X-ray diffraction studies were carried out on the mono-perchlorate and the double nitrate salts, revealing the expected structures. C1 AFRL PRSP & ERC Inc, Edwards AFB, CA 93524 USA. NASA, George C Marshall Space Flight Ctr, Prop Res Ctr ER22, Huntsville, AL 35812 USA. RP Drakes, GW (reprint author), NASA, George C Marshall Space Flight Ctr, Prop Res Ctr ER22, Huntsville, AL 35812 USA. EM Gregory.w.drake@nasa.gov NR 69 TC 9 Z9 9 U1 2 U2 3 PU WILEY-V C H VERLAG GMBH PI WEINHEIM PA PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY SN 0721-3115 J9 PROPELL EXPLOS PYROT JI Propellants Explos. Pyrotech. PD JUN PY 2006 VL 31 IS 3 BP 196 EP 204 DI 10.1002/prep.200600027 PG 9 WC Chemistry, Applied; Engineering, Chemical SC Chemistry; Engineering GA 059PD UT WOS:000238743800005 ER PT J AU Wisniewski, JP Babler, BL Bjorkman, KS Kurchakov, AV Meade, MR Miroshnichenko, AS AF Wisniewski, JP Babler, BL Bjorkman, KS Kurchakov, AV Meade, MR Miroshnichenko, AS TI The asymmetrical wind of the candidate luminous blue variable MWC 314 SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID STELLAR LINEAR-POLARIZATION; EARLY-TYPE STARS; P-CYGNI; SPECTROPOLARIMETRIC OBSERVATIONS; INTERSTELLAR POLARIZATION; WAVELENGTH DEPENDENCE; AG-CARINAE; HR CARINAE; GEOMETRY; NEBULA AB We present the results of long-term spectropolarimetric and spectroscopic monitoring of MWC 314, a candidate luminous blue variable star. We detect the first evidence of Ha variability in MWC 314 and find no apparent periodicity in this emission. The total R-band polarization is observed to vary between 2.21% and 3.00% at a position angle consistently around similar to 0 degrees, indicating the presence of a time-variable intrinsic polarization component, and hence an asymmetrical circumstellar envelope. We find suggestive evidence that MWC 314' s intrinsic polarization exhibits a wavelength-independent magnitude varying between 0.09% and 0.58% at a wavelength-independent position angle covering all four quadrants of the Stokes Q-U plane. Electron scattering off of density clumps in MWC 314' s wind is considered as the probable mechanism responsible for these variations. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. Univ Wisconsin, Space Astron Lab, Madison, WI 53706 USA. Univ Toledo, Dept Phys & Astron, Ritter Observ, Toledo, OH 43606 USA. Univ N Carolina, Dept Phys & Astron, Greensboro, NC 27402 USA. RP Wisniewski, JP (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Code 667,Bldg 21, Greenbelt, MD 20771 USA. EM jwisnie@milkyway.gsfc.nasa.gov OI Babler, Brian/0000-0002-6984-5752 NR 34 TC 10 Z9 10 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 JUN PY 2006 VL 118 IS 844 BP 820 EP 827 DI 10.1086/506182 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 057XS UT WOS:000238629100006 ER PT J AU Guyon, O Shao, M AF Guyon, O Shao, M TI The pupil-swapping coronagraph SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID PHASE-MASK; TELESCOPE AB A new coronagraph that performs destructive interference between copies of the telescope pupil in which "slices" have been swapped is studied in this paper. A fourth-order "pupil-swapping coronagraph" is particularly attractive for direct imaging of extrasolar terrestrial planets: it achieves 100% throughput at 1.4 lambda/d on a square pupil (72.5% at 1.77 lambda/d on a circular pupil), is compatible with a central obstruction and spiders, l/d and delivers sharp images of off-axis sources. Direct detection of extrasolar terrestrial planets appears theoretically feasible on a 2 to 3 m visible-wavelength telescope in space. C1 Natl Astron Observ Japan, Subaru Telescope, Hilo, HI 96720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Guyon, O (reprint author), Natl Astron Observ Japan, Subaru Telescope, 650 N Aohoku Pl, Hilo, HI 96720 USA. EM guyon@naoj.org NR 8 TC 11 Z9 11 U1 0 U2 2 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 JUN PY 2006 VL 118 IS 844 BP 860 EP 865 DI 10.1086/505586 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 057XS UT WOS:000238629100011 ER PT J AU Porter, RL Ferland, GJ Kraemer, SB Armentrout, BK Arnaud, KA Turner, TJ AF Porter, RL Ferland, GJ Kraemer, SB Armentrout, BK Arnaud, KA Turner, TJ TI A Cloudy/XSPEC interface SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article AB We discuss new functionality of the spectral simulation code Cloudy that allows the user to calculate grids with one or more initial parameters varied and formats the predicted spectra in the standard FITS format. These files can then be imported into the X-ray spectral analysis software XSPEC and used as theoretical models for observations. We present and verify a test case. Finally, we consider a few observations and discuss our results. C1 Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Lab Xray Astrophys, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Dept Phys, Joint Ctr Astrophys, Baltimore, MD 21250 USA. RP Porter, RL (reprint author), Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. OI Ferland, Gary/0000-0003-4503-6333 NR 7 TC 16 Z9 16 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 JUN PY 2006 VL 118 IS 844 BP 920 EP 923 DI 10.1086/506333 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 057XS UT WOS:000238629100017 ER PT J AU Bell, MS Teo, KBK Lacerda, RG Milne, WI Hash, DB Meyyappan, M AF Bell, MS Teo, KBK Lacerda, RG Milne, WI Hash, DB Meyyappan, M TI Carbon nanotubes by plasma-enhanced chemical vapor deposition SO PURE AND APPLIED CHEMISTRY LA English DT Article; Proceedings Paper CT 17th International Symposium on Plasma Chemistry (ISPC 17) CY AUG 07-12, 2005 CL Toronto, CANADA SP Int Union Pure & Appl Chem, Int Plasma Chem Soc DE plasma; PECVD; glow discharge; carbon; nanotubes ID GROWTH AB This paper presents the growth of vertically aligned carbon nanotubes by plasma-enhanced chemical vapor deposition (PECVD) using Ni catalyst and C2H2/NH3 feedstock. The role of plasma in aligning the carbon nanotubes during growth is investigated both experimentally and computationally, confirming that the field in the plasma sheath causes the nanotubes to be aligned. Experiments using a plasma analyzer show that C2H2 is the dominant precursor for carbon nanotube growth. The role of NH3 in the plasma chemistry is also investigated, and experimental results show how the interaction between NH3 and the C2H2 carbon feedstock in the gas phase explains the structural variation in deposited nanotubes for differing gas ratios. The effects of varying the plasma power during deposition on nanotube growth rate is also explored. Finally, the role of endothermic ion-molecule reactions in the plasma sheath is investigated by comparing measured data with simulation results. C1 Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England. NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Teo, KBK (reprint author), Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England. RI Lacerda, Rodrigo/N-2176-2014 NR 15 TC 40 Z9 41 U1 0 U2 8 PU INT UNION PURE APPLIED CHEMISTRY PI RES TRIANGLE PK PA 104 TW ALEXANDER DR, PO BOX 13757, RES TRIANGLE PK, NC 27709-3757 USA SN 0033-4545 J9 PURE APPL CHEM JI Pure Appl. Chem. PD JUN PY 2006 VL 78 IS 6 BP 1117 EP 1125 DI 10.1351/pac200678061117 PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA 053TE UT WOS:000238327300004 ER PT J AU Carney, JR Miller, JS Gump, JC Pangilinan, GI AF Carney, JR Miller, JS Gump, JC Pangilinan, GI TI Time-resolved optical measurements of the post-detonation combustion of aluminized explosives SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID PARTICLES; AIR; TEMPERATURE; IGNITION AB The dynamic observation and characterization of light emission following the detonation and subsequent combustion of an aluminized explosive is described. The temporal, spatial, and spectral specificity of the light emission are achieved using a combination of optical diagnostics. Aluminum and aluminum monoxide emission peaks are monitored as a function of time and space using streak camera based spectroscopy in a number of light collection configurations. Peak areas of selected aluminum containing species are tracked as a function of time to ascertain the relative kinetics (growth and decay of emitting species) during the energetic event. At the chosen streak camera sensitivity, aluminum emission is observed for 10 mu s following the detonation of a confined 20 g charge of PBXN-113, while aluminum monoxide emission persists longer than 20 mu s. A broadband optical emission gauge, shock velocity gauge, and fast digital framing camera are used as supplemental optical diagnostics. In-line, collimated detection is determined to be the optimum light collection geometry because it is independent of distance between the optics and the explosive charge. The chosen optical configuration also promotes a constant cylindrical collection volume that should facilitate future modeling efforts. C1 USN, Suface Warfare Ctr, Res & Technol Dept, Indian Head Div, Indian Head, MD 20640 USA. RP Carney, JR (reprint author), NASA, George C Marshall Space Flight Ctr, Qualis Corp, Space Environm Effects Facil, Huntsville, AL 35812 USA. NR 19 TC 32 Z9 34 U1 0 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 2006 VL 77 IS 6 AR 063103 DI 10.1063/1.2200766 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 059KX UT WOS:000238732800003 ER PT J AU Fixsen, DJ Wollack, EJ Kogut, A Limon, M Mirel, P Singal, J Fixsen, SM AF Fixsen, DJ Wollack, EJ Kogut, A Limon, M Mirel, P Singal, J Fixsen, SM TI Compact radiometric microwave calibrator SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID CENTIMETER WAVELENGTHS AB The calibration methods for the ARCADE II instrument are described and the accuracy estimated. The Steelcast coated aluminum cones which comprise the calibrator have a low reflection while maintaining 94% of the absorber volume within 5 mK of the base temperature (modeled). The calibrator demonstrates an absorber with the active part less than one wavelength thick and only marginally larger than the mouth of the largest horn and yet black (less than -40 dB or 0.01% reflection) over five octaves in frequency. (c) 2006 American Institute of Physics. C1 SSAI Goddard Spaceflight Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. RP Fixsen, DJ (reprint author), SSAI Goddard Spaceflight Ctr, Greenbelt, MD 20771 USA. RI Wollack, Edward/D-4467-2012; OI Wollack, Edward/0000-0002-7567-4451; Limon, Michele/0000-0002-5900-2698 NR 13 TC 11 Z9 11 U1 0 U2 1 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 2006 VL 77 IS 6 AR 064905 DI 10.1063/1.2209960 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 059KX UT WOS:000238732800055 ER PT J AU Sterritt, R Rouff, CA Hinchey, MG Rash, JL Truszkowski, W AF Sterritt, Roy Rouff, Christopher A. Hinchey, Michael G. Rash, James L. Truszkowski, Walt TI Next generation system and software architectures - Challenges from future NASA exploration missions SO SCIENCE OF COMPUTER PROGRAMMING LA English DT Article; Proceedings Paper CT 4th International Workshop on Systems/Software Architectures CY JUN, 2005 CL Las Vegas, NV DE self-*; selfware; autonomous systems; autonomic systems; agent architectures; multi-agent technology; intelligent systems; spacecraft AB The four key objective properties of a system that are required of it in order for it to qualify as "autonomic" are now well-accepted-self-configuring, self-healing, self-protecting, and self-optimizing-together with the attribute properties-viz. self-aware, environment-aware, self-monitoring and self-adjusting. This paper describes the need for next generation system software architectures, where components are agents, rather than objects masquerading as agents, and where support is provided for self-* properties (both existing self-chop and emerging self-* properties). These are discussed as exhibited in NASA missions, and in particular with reference to a NASA concept mission, ANTS, which is illustrative of future NASA exploration missions based on the technology of intelligent swarms. (c) 2006 Elsevier B.V. All rights reserved. C1 Univ Ulster, Sch Comp & Math, Newtownabbey BT37 0QB, Antrim, North Ireland. SAiC, Adv Concepts Business Unit, Mclean, VA 22102 USA. NASA, Goddard Space Flight Ctr, Informat Syst Div, Code 580, Greenbelt, MD 20771 USA. RP Sterritt, R (reprint author), Univ Ulster, Sch Comp & Math, Shore Rd, Newtownabbey BT37 0QB, Antrim, North Ireland. EM r.sterritt@ulster.ac.uk; rouffc@saic.com; Michael.G.Hinchey@nasa.gov; James.L.Rash@nasa.gov; Walt.Truszkowski@nasa.gov NR 25 TC 3 Z9 4 U1 0 U2 1 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 JUN PY 2006 VL 61 IS 1 BP 48 EP 57 DI 10.1016/j.scico.2005.11.005 PG 10 WC Computer Science, Software Engineering SC Computer Science GA 043QP UT WOS:000237616700006 ER PT J AU O'Byrne, S Danehy, PM Houwing, AFP AF O'Byrne, S Danehy, PM Houwing, AFP TI Investigation of hypersonic nozzle flow uniformity using NO fluorescence SO SHOCK WAVES LA English DT Article DE nozzle flow; fluorescence; LIF; nozzle uniformity ID LASER-INDUCED FLUORESCENCE; SHOCK TUNNELS; FRACTION; FIELDS AB Planar laser-induced fluorescence visualisation is used to investigate nonuniformities in the flow of a hypersonic conical nozzle. Possible causes for the nonuniformity are outlined and investigated, and the problem is shown to be due to a small step at the nozzle throat. Entrainment of cold boundary layer gas is postulated as the cause of the signal nonuniformity. C1 Univ New S Wales, Australian Def Force Acad, Sch Aerosp Civil & Mech Engn, Canberra, ACT 2600, Australia. NASA, Langley Res Ctr, Adv Sensing & Opt Measurement Branch, Hampton, VA 23681 USA. Australian Natl Univ, Dept Phys & Theoret Phys, Canberra, ACT 0200, Australia. RP O'Byrne, S (reprint author), Univ New S Wales, Australian Def Force Acad, Sch Aerosp Civil & Mech Engn, Canberra, ACT 2600, Australia. EM s.obyrne@adfa.edu.au NR 18 TC 3 Z9 3 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0938-1287 J9 SHOCK WAVES JI Shock Waves PD JUN PY 2006 VL 15 IS 2 BP 81 EP 87 DI 10.1007/s00193-006-0013-6 PG 7 WC Mechanics SC Mechanics GA 051DF UT WOS:000238140200003 ER PT J AU Kim, J Yang, SY Song, KD Jones, S Choi, SH AF Kim, J Yang, SY Song, KD Jones, S Choi, SH TI Performance characterization of flexible dipole rectennas for smart actuator use SO SMART MATERIALS & STRUCTURES LA English DT Article ID POWER AB The concept of power transmission by a microwave is envisioned as the best option for alleviating the complexity associated with hard-wired control circuitry in controlling smart actuators and robots such as micro-aerial vehicles, biomimetic robots and space vehicles to produce remotely maneuverable capability. A flexible dipole rectenna array is conformably adaptable on the complex structure of vehicles used for practical applications of wireless power. For these applications, various flexible dipole rectennas and arrays were designed, fabricated and characterized over a frequency range of 9-12 GHz with 20 W and 200 W amplifiers through laboratory testing. The irradiance of the microwave power was measured. Also the irradiated power, the output power and the efficiency of the rectenna arrays were evaluated along with the microwave power and frequency. The maximum voltage of 65 V-DC was observed from a series connected dipole rectenna array and the maximum current of 2.50 mA was obtained from a parallel connected rectenna array. The efficiency of dipole rectenna arrays ranges from 20% to 50% depending on the input power and the pole configuration. It was also demonstrated that the voltage, current and power output from a dipole rectenna array can be tailored by configuring the dipole rectenna elements in serial and parallel mode connections. C1 Inha Univ, Dept Mech Engn, Inchon 402751, South Korea. Norfolk State Univ, Dept Engn, Norfolk, VA 23504 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Kim, J (reprint author), Inha Univ, Dept Mech Engn, 253 Yonghyun Dong, Inchon 402751, South Korea. EM jaehwan@inha.ac.kr OI Kim, Jaehwan/0000-0002-6152-2924 NR 11 TC 33 Z9 34 U1 0 U2 7 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0964-1726 J9 SMART MATER STRUCT JI Smart Mater. Struct. PD JUN PY 2006 VL 15 IS 3 BP 809 EP 815 DI 10.1088/0964-1726/15/3/017 PG 7 WC Instruments & Instrumentation; Materials Science, Multidisciplinary SC Instruments & Instrumentation; Materials Science GA 055EW UT WOS:000238433800017 ER PT J AU Wang, J Shepard, WS Williams, KA Gattis, CB AF Wang, Jingdou Shepard, W. Steve, Jr. Williams, Keith A. Gattis, Christy B. TI Active vibration control of a plate-like structure with discontinuous boundary conditions SO SMART MATERIALS & STRUCTURES LA English DT Article; Proceedings Paper CT ASME International Mechanical Engineering Congress CY NOV 13-19, 2004 CL Anaheim, CA SP ASME ID PIEZOELECTRIC ACTUATORS; BEAM AB This research involves the application of methods to actively control the vibration of a plate-like structure with discontinuous boundary conditions. The research is motivated by the need to control vibrations on rack shelves in use on the International Space Station (ISS). Vibration of the rack shelves can adversely affect experiments being performed on those shelves. In this work, control of a rack shelf similar to those in use on the ISS is examined. Piezoelectric actuators bonded to the shelf structure are proposed as a method for controlling rack shelf vibrations. A two-dimensional asymmetric piezoelectric actuator model is first developed. The Ritz expansion method is then employed to derive the equations of motion for the combined piezoelectric actuators and rack shelf system with discontinuous boundary conditions. Model parameters from the analytical solution are used in conjunction with experimentally obtained parameters to develop a control model for the active structure. The control model is then used, together with a linear quadratic approach, to develop two different control strategies: collocated output feedback control and modal control. Results from an experimental evaluation of the two control approaches are presented. Based on the experimental results, the two control strategies are shown to be effective in controlling the first several modes of the rack shelf system at frequencies below 800 Hz. C1 Univ Alabama, Dept Mech Engn, Tuscaloosa, AL 35487 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Shepard, WS (reprint author), Univ Alabama, Dept Mech Engn, 290 Hardaway Hall,Box 870276, Tuscaloosa, AL 35487 USA. EM sshepard@eng.ua.edu NR 19 TC 4 Z9 4 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0964-1726 J9 SMART MATER STRUCT JI Smart Mater. Struct. PD JUN PY 2006 VL 15 IS 3 BP N51 EP N60 DI 10.1088/0964-1726/15/3/N01 PG 10 WC Instruments & Instrumentation; Materials Science, Multidisciplinary SC Instruments & Instrumentation; Materials Science GA 055EW UT WOS:000238433800027 ER PT J AU Kosovichev, AG Duvall, TL AF Kosovichev, A. G. Duvall, T. L., Jr. TI Active region dynamics SO SPACE SCIENCE REVIEWS LA English DT Review DE Sun : activity; Sun : heliseismology; Sun : interior; Sun : magnetic field; sunspots ID TIME-DISTANCE HELIOSEISMOLOGY; SUBPHOTOSPHERIC FLOWS; FLARING ACTIVITY; SOLAR INTERIOR; SENSITIVITY; INVERSION AB New methods of local helioseismology and uninterrupted time series of solar oscillation data from the Solar and Heliospheric Observatory (SOHO) have led to a major advance in our understanding of the structure and dynamics of active regions in the subsurface layers. The initial results show that large active regions are formed by repeated magnetic flux emergence from the deep interior, and that their roots are at least 50 Mm deep. The active regions change the temperature structure and flow dynamics of the upper convection zone, forming large circulation cells of converging flows. The helioseismic observations also indicate that the processes of magnetic energy release, flares and coronal mass ejections, might be associated with strong (1-2 km/s) shearing flows, 4-6 Mm below the surface. C1 Stanford Univ, Stanford, CA 94305 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Kosovichev, AG (reprint author), Stanford Univ, Stanford, CA 94305 USA. EM akosovichev@solar.stanford.edu RI Duvall, Thomas/C-9998-2012 NR 12 TC 14 Z9 14 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PD JUN PY 2006 VL 124 IS 1-4 BP 1 EP 12 DI 10.1007/s11214-006-9112-z PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 137VD UT WOS:000244319800001 ER PT J AU Birn, J Hesse, M Schindler, K AF Birn, J. Hesse, M. Schindler, K. TI Modeling of the magnetospheric response to the dynamic solar wind SO SPACE SCIENCE REVIEWS LA English DT Review DE magnetotail; thin current sheets; solar wind/magnetosphere interaction ID TEST PARTICLE ORBITS; MAGNETIC RECONNECTION; MAGNETOHYDRODYNAMIC SIMULATION; MAGNETOTAIL EQUILIBRIUM; CURRENT SHEETS; INJECTIONS; FIELDS; ONSET AB We discuss quasi-static and dynamic models of the magnetotail response to perturbations imposed by the solar wind, focusing particularly on the formation of thin current sheets, their structure and breakup. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Ruhr Univ Bochum, D-4630 Bochum, Germany. RP Birn, J (reprint author), Los Alamos Natl Lab, Los Alamos, NM 87545 USA. EM jbirn@lanl.gov RI Hesse, Michael/D-2031-2012; NASA MMS, Science Team/J-5393-2013 OI NASA MMS, Science Team/0000-0002-9504-5214 NR 24 TC 4 Z9 4 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PD JUN PY 2006 VL 124 IS 1-4 BP 103 EP 116 DI 10.1007/s11214-006-9100-3 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 137VD UT WOS:000244319800008 ER PT J AU Gopalswamy, N AF Gopalswamy, Nat TI Properties of interplanetary coronal mass ejections SO SPACE SCIENCE REVIEWS LA English DT Review DE coronal mass ejections; interplanetary CMEs; solar wind; magnetic clouds; shocks; solar flares; geomagnetic storms ID MAJOR GEOMAGNETIC STORMS; MAGNETIC CLOUDS; SOLAR-WIND; 1 AU; PROMINENCE ERUPTIONS; 1-AU ARRIVAL; SHOCKS; PROPAGATION; SIGNATURES; FILAMENTS AB Interplanetary coronal mass ejections (ICMEs) originating from closed field regions on the Sun are the most energetic phenomenon in the heliosphere. They cause intense geomagnetic storms and drive fast mode shocks that accelerate charged particles. ICMEs are the interplanetary manifestations of CMEs typically remote-sensed by coronagraphs. This paper summarizes the observational properties of ICMEs with reference to the ordinary solar wind and the progenitor CMEs. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gopalswamy, N (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM gopals@ssedmail.gsfc.nasa.gov RI Gopalswamy, Nat/D-3659-2012 NR 90 TC 59 Z9 60 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 2006 VL 124 IS 1-4 BP 145 EP 168 DI 10.1007/s11214-006-9102-1 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 137VD UT WOS:000244319800011 ER PT J AU DellaCorte, C AF DellaCorte, C TI Calgary - the year's biggest 'Girls Night Out? 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 1 Z9 1 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 0024-7154 J9 TRIBOL LUBR TECHNOL JI Tribol. Lubr. Technol. PD JUN PY 2006 VL 62 IS 6 BP 6 EP 6 PG 1 WC Engineering, Mechanical SC Engineering GA 042PW UT WOS:000237541900002 ER PT J AU Ozdogan, M Woodcock, CE Salvucci, GD Demir, H AF Ozdogan, Mutlu Woodcock, Curtis E. Salvucci, Guido D. Demir, Hueseyin TI Changes in summer irrigated crop area and water use in Southeastern Turkey from 1993 to 2002: Implications for current and future water resources SO WATER RESOURCES MANAGEMENT LA English DT Article DE agriculture; cotton; CROPWAT; Euphrates; evaporation; irrigation; NDVI; remote sensing; Tigris; Turkey ID LANDSAT IMAGERY; SALINITY AB Changes in summer irrigated cropland acreage and related water use are estimated from satellite remote sensing and ancillary data in semi-arid Southeastern Turkey where traditionally dry agricultural lands are being rapidly transformed into irrigated fields with the help of water from the Euphrates-Tigris Rivers. An image classification methodology based on thresholding of Landsat NDVI images from the peak summer period reveals that the total area of summer irrigated crops has increased three-fold (from 35,000 ha to over 100,000) in the Harran Plain between 1993 and 2002. Coupled analysis of annual irrigated crop area from remote sensing and potential evapotranspiration based estimates of irrigation water requirements for cotton indicate a corresponding increase in agricultural water use from about 370 million cubic meters to over one billion cubic meters, a volume in accordance with the state estimates. These estimates have important implications for understanding the rapid changes in current agricultural withdrawals in Southeastern Turkey and form a quantitative basis for exploring the changes in future water demands in the region. For example, expansion of irrigated lands have led to a steady decrease in potential evaporation due to increased roughness and decreased humidity deficit in the Harran Plain. Assuming that the changes in future evaporation conditions will be of similar nature, water use for irrigation is expected to decrease over 40 percent in future irrigation sites. Incorporating this decrease in overall planning of the irrigation projects currently under construction should lead to improved management, and by extension, sustainability of water resources in the region. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. Boston Univ, Dept Geog, Boston, MA 02215 USA. GAP Reg Dev Off, TR-63000 Samliurfa, Turkey. RP Ozdogan, M (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Mail Code 614-3, Greenbelt, MD 20771 USA. EM ozdogan@hsb.gsfc.nasa.gov RI Salvucci, Guido/I-6185-2013; OI Ozdogan, Mutlu/0000-0002-1707-3375 NR 36 TC 29 Z9 29 U1 1 U2 26 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0920-4741 EI 1573-1650 J9 WATER RESOUR MANAG JI Water Resour. Manag. PD JUN PY 2006 VL 20 IS 3 BP 467 EP 488 DI 10.1007/s11269-006-3087-0 PG 22 WC Engineering, Civil; Water Resources SC Engineering; Water Resources GA 054FO UT WOS:000238362400009 ER PT J AU Jedlovec, GJ Nair, U Haines, SL AF Jedlovec, GJ Nair, U Haines, SL TI Detection of storm damage tracks with EOS data SO WEATHER AND FORECASTING LA English DT Article ID UNITED-STATES; TORNADOES; LANDSAT; IMAGER; SATELLITE; OKLAHOMA; SYSTEM AB The damage surveys conducted by the NWS in the aftermath of a reported tornadic event are used to document the location of the tornado ground damage track (pathlength and width) and an estimation of the tornado intensity. This study explores the possibility of using near-real-time medium and high spatial resolution satellite imagery from the NASA Earth Observing System satellites to provide additional information for the surveys. Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) data were used to study the damage tracks from three tornadic storms: the La Plata, Maryland, storm of 28 April 2002 and the Ellsinore and Marquand, Missouri, storms of 24 April 2002. These storms varied in intensity and occurred over regions with significantly different land cover. It was found that, depending on the nature of the land cover, tornado damage tracks from intense storms (F1 or greater) and hail storms may be evident in ASTER, Landsat, and MODIS satellite imagery. In areas where the land cover is dominated by forests, the scar patterns can show up very clearly, while in areas of grassland and regions with few trees, scar patterns are not as obvious or cannot be seen at all in the satellite imagery. The detection of previously unidentified segments of a damage track caused by the 24 April 2002 Marquand, Missouri, tornado demonstrates the utility of satellite imagery for damage surveys. However, the capability to detect tornado tracks in satellite imagery depends on the ability to observe the ground without obstruction from space and appears to be as much dependent on the nature of the underlying surface and land cover as on the severity of the tornadic storm. C1 NASA, Marshall Space Flight Ctr, XD11, Huntsville, AL 35805 USA. Univ Alabama, Ctr Earth Syst Sci, Huntsville, AL 35899 USA. RP Jedlovec, GJ (reprint author), NASA, Marshall Space Flight Ctr, XD11, 320 Sparkman Dr, Huntsville, AL 35805 USA. EM gary.jedlovec@nasa.gov NR 34 TC 6 Z9 9 U1 2 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 2006 VL 21 IS 3 BP 249 EP 267 DI 10.1175/WAF923.1 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 058UN UT WOS:000238690200001 ER PT J AU Buchsbaum, RN Catena, J Hutchins, E James-Pirri, MJ AF Buchsbaum, RN Catena, J Hutchins, E James-Pirri, MJ TI Changes in salt marsh vegetation, Phragmites australis, and nekton in response to increased tidal flushing in a new England salt marsh SO WETLANDS LA English DT Article DE marsh; coastal wetland; wetland restoration; Phragmites australis; Spartina alterniflora; salt marsh fish; tidal restriction ID COMMON REED; NORTH-AMERICA; EXPANSION; RESTORATION; CONNECTICUT; MANAGEMENT; INVASION; PATTERNS; IMPACT AB This study examined the response of Argilla Marsh in Ipswich, Massachusetts, USA to increased tidal flushing instituted to restore a salt marsh invaded by Phragmites australis. In late fall 1998, we replaced the old 0.9-m-diameter culvert feeding this marsh with a 2.4 x 1.5-m box culvert, thus increasing both the volume of tidal exchange and porewater salinity. We carried out yearly sampling of vegetation for two years pre-restoration and for four years after restoration. Analysis of Similarities (ANOSIM) showed that the plant community on the restored marsh had changed after restoration but that on the reference marshes had not. Over 80% of the change in the restored marsh was attributed to an increase in Spartina alterniflora cover and decreases in the cover of Phragmites australis, Typha angustifolia, and Solidago sempervirens. The two brackish species, P. australis and T. angustifolia showed an immediate negative response to the increased flooding and salinity. Surviving P. australis culms in the restored marsh were shorter in stature than they were prior to restoration, suggesting that the increased flooding and porewater salinities had lowered the productivity of this species. The increase in S. alterniflora post-restoration fit an exponential curve, indicating that there was a lag in its response initially, but then it expanded rapidly and was still in a very rapid expansion phase after four years. Despite an overall decline of P. australis on the scale of the whole marsh, there was a great deal of variation in responses of individual patches of P. australis to the restoration. Some declined, some were unchanged, and. some even increased. The response of nekton to the restoration was less obvious than that of vegetation. Before restoration, the creek system in the tidally restricted marsh functioned like an impoundment that was only marginally connected to the larger salt marsh ecosystem. At that time, seining indicated that more species of nekton occurred at greater densities in creeks in the tidally restricted marsh than in the downstream reference. Increasing the tidal amplitude in the restored marsh resulted in an overall decline in the catch per unit effort there. In contrast to the creeks, the Spartina-dominated section of the flooded marsh surface in the restored marsh did harbor more Fundulus heteroclitus, particularly the smaller size class, than did the downstream reference marsh or a P. australis patch in the restored marsh. Our analysis of vegetation and nekton suggests that Argilla Marsh was still adjusting to hydrologic changes four years after restoration. C1 Massachusetts Audubon Soc, Wenham, MA 01984 USA. Natl Marine Fisheries Serv, Gloucester, MA 01930 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. RP Buchsbaum, RN (reprint author), Massachusetts Audubon Soc, 346 Grapevine Rd, Wenham, MA 01984 USA. EM rbuchsbaum@massaudubon.org NR 37 TC 20 Z9 20 U1 6 U2 36 PU SOC WETLAND SCIENTISTS PI LAWRENCE PA 810 E TENTH ST, P O BOX 1897, LAWRENCE, KS 66044 USA SN 0277-5212 J9 WETLANDS JI Wetlands PD JUN PY 2006 VL 26 IS 2 BP 544 EP 557 DI 10.1672/0277-5212(2006)26[544:CISMVP]2.0.CO;2 PG 14 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA 058YY UT WOS:000238701700024 ER PT J AU Ricca, A Bauschlicher, CW AF Ricca, A Bauschlicher, CW TI The physisorption of CH4 on graphite and on a (9,0) carbon nanotube SO CHEMICAL PHYSICS LA English DT Article DE carbon nanotubes; sensors; DFT; CH4 ID ADSORPTION; BUNDLES; METHANE AB Our best estimates for the binding energy of methane on graphite, on a (9,0) single-walled carbon nanotube (SWCNT) and at the groove site between two (9,0) SWCNTs are 3.5 +/- 1, 2.9 +/- 1, and 5.6 +/- 1 kcal/mol, respectively. Our computed values are in good agreement with the available experimental values. The calculations, therefore, support the current view that methane initially fills the groove site and then covers the outer nanotube surfaces, and that the binding energy of graphite is intermediate between the binding energy values for these two nanotube binding sites. In turn, the experimental results support the use of a cluster model in conjunction with the MP2 level of theory for the study of molecules that are weakly bound to SWCNTs. (c) 2005 Elsevier B.V. All rights reserved. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Bauschlicher, CW (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Mail Stop 230-3, Moffett Field, CA 94035 USA. EM ricca@pegasus.arc.nasa.gov; Bauschlicher@nasa.gov NR 18 TC 35 Z9 36 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD MAY 31 PY 2006 VL 324 IS 2-3 BP 455 EP 458 DI 10.1016/j.chemphys.2005.11.010 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 052ZG UT WOS:000238272100020 ER PT J AU Bauschlicher, CW Lawson, JW AF Bauschlicher, Charles W., Jr. Lawson, John W. TI Current-voltage curves for molecular junctions computed using all-electron basis sets SO CHEMICAL PHYSICS LA English DT Article DE molecular electronics; basis set effects; DFT; greens function; Au surface ID GAUSSIAN-BASIS SETS; ATOMS; POTENTIALS; FORMALISM; TRANSPORT; DEVICES; ENERGY; WIRES AB We present current-voltage (I-V) curves computed using all-electron basis sets on the conducting molecule. The all-electron results are very similar to previous results obtained using effective core potentials (ECP). A hybrid integration scheme is used that keeps the all-electron calculations cost competitive with respect to the ECP calculations. By neglecting the coupling of states to the contacts below a fixed energy cutoff, the density matrix for the core electrons can be evaluated analytically. The full density matrix is formed by adding this core contribution to the valence part that is evaluated numerically. Expanding the definition of the core in the all-electron calculations significantly reduces the computational effort and, up to biases of about 2 V, the results are very similar to those obtained using more rigorous approaches. The convergence of the I-V curves and transmission coefficients with respect to basis set is discussed. The addition of diffuse functions is critical in approaching basis set completeness. (c) 2006 Elsevier B.V. All rights reserved. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Bauschlicher, CW (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Mail Stop 230-3, Moffett Field, CA 94035 USA. EM Charles.W.Bauschlicher@nasa.gov; John.W.Lawson@nasa.gov NR 25 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD MAY 31 PY 2006 VL 324 IS 2-3 BP 647 EP 652 DI 10.1016/j.chemphys.2005.12.025 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 052ZG UT WOS:000238272100042 ER PT J AU Steinbrecht, W Claude, H Schonenborn, F McDermid, IS Leblanc, T Godin, S Song, T Swart, DPJ Meijer, YJ Bodeker, GE Connor, BJ Kampfer, N Hocke, K Calisesi, Y Schneider, N de la Noe, J Parrish, AD Boyd, IS Bruhl, C Steil, B Giorgetta, MA Manzini, E Thomason, LW Zawodny, JM McCormick, MP Russell, JM Bhartia, PK Stolarski, RS Hollandsworth-Frith, SM AF Steinbrecht, W. Claude, H. Schoenenborn, F. McDermid, I. S. Leblanc, T. Godin, S. Song, T. Swart, D. P. J. Meijer, Y. J. Bodeker, G. E. Connor, B. J. Kaempfer, N. Hocke, K. Calisesi, Y. Schneider, N. de la Noe, J. Parrish, A. D. Boyd, I. S. Bruehl, C. Steil, B. Giorgetta, M. A. Manzini, E. Thomason, L. W. Zawodny, J. M. McCormick, M. P. Russell, J. M., III Bhartia, P. K. Stolarski, R. S. Hollandsworth-Frith, S. M. TI Long-term evolution of upper stratospheric ozone at selected stations of the Network for the Detection of Stratospheric Change (NDSC) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID QUASI-BIENNIAL OSCILLATION; HALOGEN OCCULTATION EXPERIMENT; SOLAR BACKSCATTER ULTRAVIOLET; GENERAL-CIRCULATION MODEL; CHEMISTRY-CLIMATE MODEL; ART. NO. 4049; MIDDLE ATMOSPHERE; NEW-ZEALAND; MAUNA-LOA; LIDAR MEASUREMENTS AB The long-term evolution of upper stratospheric ozone has been recorded by lidars and microwave radiometers within the ground-based Network for the Detection of Stratospheric Change (NDSC), and by the space-borne Solar Backscatter Ultra-Violet instruments (SBUV), Stratospheric Aerosol and Gas Experiment (SAGE), and Halogen Occultation Experiment (HALOE). Climatological mean differences between these instruments are typically smaller than 5% between 25 and 50 km. Ozone anomaly time series from all instruments, averaged from 35 to 45 km altitude, track each other very well and typically agree within 3 to 5%. SBUV seems to have a slight positive drift against the other instruments. The corresponding 1979 to 1999 period from a transient simulation by the fully coupled MAECHAM4-CHEM chemistry climate model reproduces many features of the observed anomalies. However, in the upper stratosphere the model shows too low ozone values and too negative ozone trends, probably due to an underestimation of methane and a consequent overestimation of ClO. The combination of all observational data sets provides a very consistent picture, with a long-term stability of 2% or better. Upper stratospheric ozone shows three main features: (1) a decline by 10 to 15% since 1980, due to chemical destruction by chlorine; (2) two to three year fluctuations by 5 to 10%, due to the Quasi-Biennial Oscillation (QBO); (3) an 11-year oscillation by about 5%, due to the 11-year solar cycle. The 1979 to 1997 ozone trends are larger at the southern mid-latitude station Lauder (45 degrees S), reaching -8%/decade, compared to only about -6%/decade at Table Mountain (35 degrees N), Haute Provence/Bordeaux (approximate to 45 degrees N), and Hohenpeissenberg/ Bern(approximate to 47 degrees N). At Lauder, Hawaii (20 degrees N), Table Mountain, and Haute Provence, ozone residuals after subtraction of QBO- and solar cycle effects have levelled off in recent years, or are even increasing. Assuming a turning point in January 1997, the change of trend is largest at southern mid-latitude Lauder, +11%/decade, compared to +7%/decade at northern mid-latitudes. This points to a beginning recovery of upper stratospheric ozone. However, chlorine levels are still very high and ozone will remain vulnerable. At this point the most northerly mid-latitude station, Hohenpeissenberg/ Bern differs from the other stations, and shows much less clear evidence for a beginning recovery, with a change of trend in 1997 by only +3%/decade. In fact, record low upper stratospheric ozone values were observed at Hohenpeissenberg/ Bern, and to a lesser degree at Table Mountain and Haute Provence, in the winters 2003/2004 and 2004/2005. C1 Meteorol Observ Hohenpeissenberg, German Weather Serv, D-82383 Hohenpeissenberg, Germany. NASA, JPL, Table Mt Facil, Wrightwood, CA 92397 USA. CNRS, Serv Aeron, F-75004 Paris, France. RIVM, NL-3720 BA Bilthoven, Netherlands. NIWA, Omakau, Central Otago, New Zealand. Univ Bern, Inst Appl Phys, CH-3012 Bern, Switzerland. Univ Bordeaux 1, OASU, CNRS, INSU, F-33270 Floirac, France. Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA. NIWA ERI, Ann Arbor, MI 48108 USA. Max Planck Inst Chem, D-55028 Mainz, Germany. Max Planck Inst Meteorol, D-20146 Hamburg, Germany. Ist Nazl Geofis & Vulcanol, I-40128 Bologna, Italy. NASA, LARC, Hampton, VA 23681 USA. Hampton Univ, Hampton, VA 23668 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Steinbrecht, W (reprint author), Meteorol Observ Hohenpeissenberg, German Weather Serv, Albin Schwaiger Weg 10, D-82383 Hohenpeissenberg, Germany. EM wolfgang.steinbrecht@dwd.de; hans.claude@dwd.de RI Steinbrecht, Wolfgang/G-6113-2010; Manzini, Elisa/H-5760-2011; Stolarski, Richard/B-8499-2013; Bhartia, Pawan/A-4209-2016 OI Steinbrecht, Wolfgang/0000-0003-0680-6729; Stolarski, Richard/0000-0001-8722-4012; Bhartia, Pawan/0000-0001-8307-9137 NR 74 TC 56 Z9 56 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 31 PY 2006 VL 111 IS D10 AR D10308 DI 10.1029/2005JD006454 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 050EP UT WOS:000238070600005 ER EF