FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Yang, RG Chen, G Snyder, GJ Fleurial, JP AF Yang, RG Chen, G Snyder, GJ Fleurial, JP TI Multistage thermoelectric microcoolers SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID DIFFERENTIAL EFFICIENCY; TEMPERATURE-DEPENDENCE; THRESHOLD CURRENT; COOLER; LASERS AB Multistage thermoelectric coolers have been used for a long time because they offer a larger temperature difference than single-stage thermoelectric coolers. Microelectromechanical systems technology leads to the possibility to fabricate multistage thermoelectric microcoolers in batches without much increase in complexity compared to single-stage cooler fabrication. In this paper, we design and analyze such multistage coolers, focusing on the optimization of the maximum temperature difference, which is of particular interest for multistage microcoolers. As an example, a two-stage thermoelectric microcooler is designed for the thermal management of a 10 mW mid-infrared laser. The heat leakage issue, the most important degradation mechanism for the performance of thermoelectric microcoolers, is discussed and possible solutions are also outlined. (C) 2004 American Institute of Physics. C1 MIT, Dept Mech Engn, Cambridge, MA 02139 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yang, RG (reprint author), MIT, Dept Mech Engn, Cambridge, MA 02139 USA. EM gchen2@mit.edu RI Snyder, G. Jeffrey/E-4453-2011; Yang, Ronggui/H-1278-2011; Chen, Gang/J-1325-2014; Snyder, G/I-2263-2015 OI Snyder, G. Jeffrey/0000-0003-1414-8682; Chen, Gang/0000-0002-3968-8530; NR 24 TC 20 Z9 21 U1 0 U2 13 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 15 PY 2004 VL 95 IS 12 BP 8226 EP 8232 DI 10.1063/1.1737473 PG 7 WC Physics, Applied SC Physics GA 826QK UT WOS:000221843400103 ER PT J AU Lu, G Onsager, TG Le, G Russell, CT AF Lu, G Onsager, TG Le, G Russell, CT TI Ion injections and magnetic field oscillations near the high-latitude magnetopause associated with solar wind dynamic pressure enhancement SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE ion injections; magnetospheric dynamics; solar wind pressure pulse ID BOUNDARY-LAYER; AURORAL OVAL; DAYSIDE MAGNETOPAUSE; MAGNETOSHEATH PLASMA; EARTHS MAGNETOPAUSE; POLAR CUSP; MAGNETOSPHERE; RECONNECTION; INTERPLANETARY; CONVECTION AB The characteristics of particles and magnetic fields associated with a step-like enhancement in solar wind dynamic pressure are investigated by using observations from the Polar spacecraft. At the time, Polar was located near its apogee of similar to9 R-E at high latitude in the afternoon sector. Impulsive, energy-dispersed injections of ions were observed by Polar in both parallel and antiparallel pitch angle directions, with a much shorter duration in the parallel direction (toward the Earth) than in the antiparallel direction (away from the Earth). The energies of the injected ions ranged from similar to200 eV to a few keV, and they are considered of magnetosheath origin. The energy dispersion of the injected ions is consistent with the interpretation of the velocity filter or time-of-flight effect as the magnetosheath ions enter the magnetosphere and propagate downward and then are mirrored at low altitude where magnetic field lines converge. It is estimated that the entrance of the magnetosheath ions was located similar to3.9-7.5 R-E away from Polar, and the distance from the spacecraft to the mirror point was similar to7.7-8.1 R-E, corresponding to similar to830-3600 km in altitude. The Polar data clearly favor magnetic reconnection as the primary mechanism for the transport of magnetosheath plasmas into the magnetosphere. A good correspondence is found between the magnetic field oscillation and the intermittence of the ion injections, implying that the impulsive ion injections were a consequence of the intermittent magnetic reconnection at the high-latitude magnetopause that had been modulated by compressional waves produced by the solar wind dynamic pressure enhancement. C1 Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Electrodynam Branch, Greenbelt, MD 20771 USA. NOAA, Space Environm Ctr, Boulder, CO 80305 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. RP Lu, G (reprint author), Natl Ctr Atmospher Res, High Altitude Observ, 345 Mitchell Lane, Boulder, CO 80307 USA. EM ganglu@ncar.ucar.edu; terry.onsager@noaa.gov; guan.le@gsfc.nasa.gov; ctrussel@igpp.ucla.edu RI Lu, Gang/A-6669-2011; Le, Guan/C-9524-2012 OI Le, Guan/0000-0002-9504-5214 NR 33 TC 12 Z9 12 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 15 PY 2004 VL 109 IS A6 AR A06208 DI 10.1029/2003JA010297 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 833HD UT WOS:000222326800001 ER PT J AU Tishkovets, VP Mishchenko, MI AF Tishkovets, VP Mishchenko, MI TI Coherent backscattering of light by a layer of discrete random medium SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE coherent backscattering; multiple scattering; polarization ID SPHERICAL-PARTICLES; WEAK LOCALIZATION; DISORDERED MEDIA; POLARIZED-LIGHT; SCATTERING; EQUATION AB We consider the problem of backscattering of light by a layer of discrete random medium illuminated by an obliquely incident plane electromagnetic wave. The multiply scattered reflected radiation is assumed to consist of incoherent and coherent parts, the coherent part being caused by the interference of multiply scattered waves. Formulas describing the characteristics of the reflected radiation are derived assuming that the scattering particles are spherical. The formula for the incoherent contribution reproduces the standard vector radiative transfer equation. The interference contribution is expressed in terms of a system of Fredholm integral equations with kernels containing Bessel functions. The special case of the backscattering direction is considered in detail. It is shown that the angular width of the backscattering interference peak depends on the polar angle of the incident wave and on the azimuth angle of the reflection direction. (C) 2003 Elsevier Ltd. All rights reserved. C1 Kharkov Natl Univ, Inst Astron, UA-61022 Kharkov, Ukraine. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Mishchenko, MI (reprint author), Kharkov Natl Univ, Inst Astron, Sumskaya St 35, UA-61022 Kharkov, Ukraine. EM tishkovets@astron.kharkov.ua; mmishchenko@giss.nasa.gov RI Mishchenko, Michael/D-4426-2012 NR 29 TC 28 Z9 28 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 JUN 15 PY 2004 VL 86 IS 2 BP 161 EP 180 DI 10.1016/s0022-4073(03)00281-4 PG 20 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 817XK UT WOS:000221210000004 ER PT J AU Goorjian, PM Cundiff, ST AF Goorjian, PM Cundiff, ST TI Nonlinear effects on the carrier-envelope phase SO OPTICS LETTERS LA English DT Article ID OPTICAL FREQUENCY-SYNTHESIS; MAXWELL EQUATIONS; LIGHT-PULSES; SOLITONS AB Calculations, using the Maxwell equations, are presented of nonlinear effects on the carrier-envelope phase for pulse durations in the two-optical-cycle range for pulses propagating in sapphire. Initially, with increasing pulse intensity the carrier-envelope phase increases monotonically. However, at higher intensities there is a turnabout in the direction of the phase change and a large change in the phase that is caused by a warping of the envelope from strong nonlinear effects. The Kerr nonlinear response occurs on a time scale of similar to1 fs and gives significantly different results from those obtained by assuming an instantaneous response. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Boulder, CO 80309 USA. RP NASA, Ames Res Ctr, M-S 19-44, Moffett Field, CA 94035 USA. EM pmgoorjian@arc.nasa.gov RI Cundiff, Steven/B-4974-2009 OI Cundiff, Steven/0000-0002-7119-5197 NR 17 TC 11 Z9 14 U1 1 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 EI 1539-4794 J9 OPT LETT JI Opt. Lett. PD JUN 15 PY 2004 VL 29 IS 12 BP 1363 EP 1365 DI 10.1364/OL.29.001363 PG 3 WC Optics SC Optics GA 825KN UT WOS:000221756000019 PM 15233436 ER PT J AU Harcombe, PA Greene, SE Kramer, MG Acker, SA Spies, TA Valentine, T AF Harcombe, PA Greene, SE Kramer, MG Acker, SA Spies, TA Valentine, T TI The influence of fire and windthrow dynamics on a coastal spruce-hemlock forest in Oregon, USA, based on aerial photographs spanning 40 years SO FOREST ECOLOGY AND MANAGEMENT LA English DT Article DE blowdown; stand-structure; stand development; disturbance ID TEMPERATE RAIN-FOREST; TSUGA-HETEROPHYLLA FOREST; TIERRA-DEL-FUEGO; PICEA-SITCHENSIS; SILVICULTURAL IMPLICATIONS; PACIFIC-NORTHWEST; VANCOUVER-ISLAND; DISTURBANCE; LANDSCAPE; WIND AB To gain understanding of patterns in forest structure and their causes, we mapped the distribution of three canopy cover classes and measured change in one of them over 40 years using aerial photographs for the 500 ha Neskowin Crest Research Natural Area (Lincoln and Tillamook Counties, Oregon). One class (fine texture, trees of uniform crown diameter and height) covered about half the area; it was identified as second growth originating after a large regional fire in 1845. The other major class (coarse texture, trees of variable crown diameter and height), occupying about 35% of the area, was unburned or partially hurried in 1845. The third class (openings with down stems visible on the ground) was blowdown patches. The blowdown patches were very small in 1953; they grew incrementally, and by 1994 had coalesced into a large patch occupying about 15% of the area. A long-term windstorm susceptibility model developed for southeast Alaska identified the region where the blowdown patch occurred as being very susceptible to maritime windstorm disturbance. This correspondence between predicted susceptibility to damage and actual blowdown supports the hypothesis that windstorm effects may be strongly constrained by topography. The results also suggest that blowdown in storm-susceptible topographic settings can be the result of multiple windstorm events over time, rather than a single event. The resulting forest is a mosaic of large multiaged chronic-disturbance patches embedded in a matrix structured by fine-scale patch processes. A consequence of a constraint on blowdown is that at the scale of hundreds of hectares biomass may not fluctuate strongly over time unless stand-destroying fires occur. (C) 2004 Elsevier B.V. All rights reserved. C1 Rice Univ, Dept Ecol & Evolutionary Biol, Houston, TX 77005 USA. USDA, Forest Serv, Pacific NW Res Stn, Forestry Sci Lab, Corvallis, OR 97331 USA. NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Moffett Field, CA 94035 USA. RP Harcombe, PA (reprint author), Rice Univ, Dept Ecol & Evolutionary Biol, 6100 Main St, Houston, TX 77005 USA. EM harcomb@rice.edu NR 60 TC 17 Z9 18 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-1127 J9 FOREST ECOL MANAG JI For. Ecol. Manage. PD JUN 14 PY 2004 VL 194 IS 1-3 BP 71 EP 82 DI 10.1016/j.foreco.2004.02.016 PG 12 WC Forestry SC Forestry GA 827TT UT WOS:000221924600007 ER PT J AU Talebian, M Fielding, EJ Funning, GJ Ghorashi, M Jackson, J Nazari, H Parsons, B Priestley, K Rosen, PA Walker, R Wright, TJ AF Talebian, M Fielding, EJ Funning, GJ Ghorashi, M Jackson, J Nazari, H Parsons, B Priestley, K Rosen, PA Walker, R Wright, TJ TI The 2003 Bam (Iran) earthquake: Rupture of a blind strike-slip fault SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SURFACE DEFORMATION; SOURCE PARAMETERS; SOUTHEAST IRAN; GOWK FAULT; SE IRAN; INTERFEROMETRY AB AnM(w) 6.5 earthquake devastated the town of Bam in southeast Iran on 26 December 2003. Surface displacements and decorrelation effects, mapped using Envisat radar data, reveal that over 2 m of slip occurred at depth on a fault that had not previously been identified. It is common for earthquakes to occur on blind faults which, despite their name, usually produce long-term surface effects by which their existence may be recognised. However, in this case there is a complete absence of morphological features associated with the seismogenic fault that destroyed Bam. C1 Geol Survey Iran, Tehran, Iran. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Cambridge, Ctr Observat & Modelling Earthquakes & Tecton, Dept Earth Sci, Cambridge, England. Univ Oxford, Ctr Observat & Modelling Earthquakes & Tecton, Dept Earth Sci, Oxford, England. RP Talebian, M (reprint author), Geol Survey Iran, Azadi Sq,Meraj St,POB 13185-1494, Tehran, Iran. EM gareth.funning@earth.ox.ac.uk RI Funning, Gareth/F-6926-2011; Wright, Tim/A-5892-2011; Walker, Richard/D-9908-2011; Parsons, Barry/K-4716-2012; NCEO, COMET+`/A-3443-2013; Fielding, Eric/A-1288-2007; OI Wright, Tim/0000-0001-8338-5935; Fielding, Eric/0000-0002-6648-8067; Funning, Gareth/0000-0002-8247-0545 NR 15 TC 104 Z9 110 U1 1 U2 11 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 11 PY 2004 VL 31 IS 11 AR L11611 DI 10.1029/2004GL020058 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 829XM UT WOS:000222085000005 ER PT J AU Kashlinsky, A Arendt, R Gardner, JP Mather, JC Moseley, SH AF Kashlinsky, A Arendt, R Gardner, JP Mather, JC Moseley, SH TI Detecting population III stars through observations of near-infrared cosmic infrared background anisotropies SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; cosmology : theory; diffuse radiation; large-scale structure of universe ID PROBE WMAP OBSERVATIONS; COBE DIRBE MAPS; 1ST STARS; BRIGHTNESS FLUCTUATIONS; TENTATIVE DETECTION; EXPERIMENT SEARCH; GALAXY COUNTS; MU-M; EMISSION; SPECTRUM AB Following the successful mapping of the last scattering surface by the Wilkinson Microwave Anisotropy Probe (WMAP) and balloon experiments, the epoch of the first stars, when Population III stars formed, is emerging as the next cosmological frontier. It is not clear what these stars' properties were, when they formed, or how long their era lasted before leading to the stars and galaxies we see today. We show that these questions can be answered with the current and future measurements of the near-IR cosmic infrared background (CIB). Theoretical arguments suggest that Population III stars were very massive and short-lived stars that formed at z similar to 10-20 at rare peaks of the density field in the cold dark matter universe. Because Population III stars probably formed individually in small minihalos, they are not directly accessible to current telescopic studies. We show that these stars left a strong and measurable signature via their contribution to the CIB anisotropies for a wide range of their formation scenarios. The excess in the recently measured near-IR CIB anisotropies over that from normal galaxies can be explained by contribution from early Population III stars. These results imply that Population III were indeed very massive stars and that their epoch started at z similar to 20 and lasted past z less than or similar to 13. We show the importance of accurately measuring the CIB anisotropies produced by Population III with future space-based missions. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 685, Greenbelt, MD 20771 USA. EM kashlinsky@stars.gsfc.nasa.gov RI Moseley, Harvey/D-5069-2012; OI Arendt, Richard/0000-0001-8403-8548 NR 46 TC 64 Z9 64 U1 1 U2 2 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 2004 VL 608 IS 1 BP 1 EP 9 DI 10.1086/386365 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827EG UT WOS:000221881200001 ER PT J AU Nolta, MR Wright, EL Page, L Bennett, CL Halpern, M Hinshaw, G Jarosik, N Kogut, A Limon, M Meyer, SS Spergel, DN Tucker, GS Wollack, E AF Nolta, MR Wright, EL Page, L Bennett, CL Halpern, M Hinshaw, G Jarosik, N Kogut, A Limon, M Meyer, SS Spergel, DN Tucker, GS Wollack, E TI First year Wilkinson Microwave Anisotropy Probe observations: Dark energy induced correlation with radio sources SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations ID ANGULAR POWER SPECTRUM; WMAP OBSERVATIONS; COSMOLOGICAL CONSTANT; SUPERNOVAE; EMISSION; UNIVERSE; MAPS; SKY AB The first-year Wilkinson Microwave Anisotropy Probe (WMAP) data, in combination with any one of a number of other cosmic probes, show that we live in a flat Lambda-dominated cold dark matter (CDM) universe with Omega(m) approximate to 0.27 and Omega(Lambda) approximate to 0.73. In this model the late-time action of the dark energy, through the integrated Sachs-Wolfe effect, should produce cosmic microwave background (CMB) anisotropies correlated with matter density fluctuations at zless than or similar to2 (Crittenden & Turok 1996). The measurement of such a signal is an important independent check of the model. We cross-correlate the NRAO VLA Sky Survey (NVSS) radio source catalog (Condon et al. 1998) with the WMAP data in search of this signal, and see indications of the expected correlation. Assuming a flat LambdaCDM cosmology, we find Omega(Lambda) > 0 (95% CL, statistical errors only) with the peak of the likelihood at Omega(Lambda) = 0.68, consistent with the preferred WMAP value. A closed model with Omega(m) = 1.28, h = 0.33, and no dark energy component (Omega(Lambda) = 0), marginally consistent with the WMAP CMB TT angular power spectrum, would produce an anticorrelation between the matter distribution and the CMB. Our analysis of the cross-correlation of the WMAP data with the NVSS catalog rejects this cosmology at the 3sigma level. C1 Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. UCLA Astron, Los Angeles, CA 90095 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ British Columbia, Dept Phys & Astron, Vancouver, BC V6T 1Z1, Canada. Univ Chicago, Ctr Cosmol Phys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Dept Phys & Astrophys, Chicago, IL 60637 USA. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. Brown Univ, Dept Phys, Providence, RI 02912 USA. RP Nolta, MR (reprint author), Princeton Univ, Dept Phys, Jadwin Hall, Princeton, NJ 08544 USA. EM mrnolta@princeton.edu RI Kogut, Alan/D-6293-2012; Spergel, David/A-4410-2011; Wollack, Edward/D-4467-2012; OI Wollack, Edward/0000-0002-7567-4451; Limon, Michele/0000-0002-5900-2698 NR 27 TC 146 Z9 147 U1 0 U2 1 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 2004 VL 608 IS 1 BP 10 EP 15 DI 10.1086/386536 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827EG UT WOS:000221881200002 ER PT J AU Kigure, H Uchida, Y Nakamura, M Hirose, S Cameron, R AF Kigure, H Uchida, Y Nakamura, M Hirose, S Cameron, R TI Distribution of Faraday rotation measure in jets from active galactic nuclei. II. Prediction from our sweeping magnetic twist model for the wiggled parts of active galactic nucleus jets and tails SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : jets; magnetic fields; MHD; polarization ID DOUBLE RADIO-SOURCES; TRANS-ALFVENIC JETS; ACCRETION DISKS; MAGNETODYNAMICAL ACCELERATION; NUMERICAL SIMULATIONS; ASTROPHYSICAL JETS; VLA OBSERVATIONS; MECHANISM; FIELDS; DYNAMICS AB Distributions of Faraday rotation measure (FRM) and the projected magnetic field derived by a three-imensional simulation of MHD jets are investigated based on our "weeping magnetic twist model.'' FRM and Stokes parameters were calculated to be compared with radio observations of large-scale wiggled AGN jets on kiloparsec scales. We propose that the FRM distribution can be used to discuss the three-dimensional structure of the magnetic field around jets and the validity of existing theoretical models, together with the projected magnetic field derived from Stokes parameters. In a previous paper we investigated the basic straight part of AGN jets by using the result of a two-dimensional axisymmetric simulation. The derived FRM distribution has a general tendency to have a gradient across the jet axis, which is due to the toroidal component of the magnetic field generated by the rotation of the accretion disk. In this paper we consider the wiggled structure of the AGN jets by using the result of a three-dimensional simulation. Our numerical results show that the distributions of FRM and the projected magnetic field have a clear correlation with the large-scale structure of the jet itself, namely, three-dimensional helix. Distributions, seeing the jet from a certain direction, show a good matching with those in a part of the 3C 449 jet. This suggests that the jet has a helical structure and that the magnetic field ( especially the toroidal component) plays an important role in the dynamics of the wiggle formation because it is due to a current-driven helical kink instability in our model. C1 Kyoto Univ, Kwasan & Hida Observ, Kyoto 6078471, Japan. Sci Univ Tokyo, Dept Phys, Shinjuku Ku, Tokyo 1628601, Japan. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. RP Kigure, H (reprint author), Kyoto Univ, Kwasan & Hida Observ, Kyoto 6078471, Japan. EM kigure@kwasan.kyoto-u.ac.jp NR 37 TC 8 Z9 8 U1 0 U2 1 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 2004 VL 608 IS 1 BP 119 EP 135 DI 10.1086/386538 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827EG UT WOS:000221881200011 ER PT J AU McKernan, B Yaqoob, T AF McKernan, B Yaqoob, T TI High-resolution X-ray spectroscopy of the FeK complex in IC 4329A SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; galaxies : active; galaxies : individual (IC 4329A); galaxies : Seyfert; techniques : spectroscopic; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; SEYFERT 1 GALAXIES; VELOCITY IONIZED OUTFLOW; IRON EMISSION-LINE; XMM-NEWTON; BLACK-HOLE; IC 4329A; BEPPOSAX OBSERVATIONS; GRATING SPECTROSCOPY; COMPTON REFLECTION AB We report the detection of complex Fe K line emission from a Chandra High Energy Transmission Grating Spectrometer (HETGS) observation of the Seyfert 1 galaxy IC 4329A. The line emission is double-peaked, one peak centered at similar to6.3 keVand the other at similar to6.9 keV in the source rest frame. When modeled by Gaussians, the lower energy peak is resolved by the high-energy grating at greater than 99% confidence, while the higher energy peak is resolved at only less than 90% confidence. The best-fitting widths are similar to21,000 and similar to4000 km s(-1) FWHM for the similar to6.3 and similar to6.9 keV peaks, respectively. If the peaks correspond to two distinct emission lines, then the peak energies are redshifted with respect to the expected line energies of Fe I Kalpha and Fe xxvi Lyalpha by at least 650 and 950 km s(-1), respectively. Alternatively, the Fe K line profile may be due to a single line from a relativistic accretion disk. In that case, the inclination angle of the disk is required to be 24(-1)(+9) degrees, the outer radius is constrained to several tens of gravitational radii, and the radial line emissivity is flatter than r(-0.7). Another possibility is that both peaks are due to distinct lines but that each one is relativistically broadened by a disk. In that case, the lower energy peak could correspond to emission from Fe in a low ionization state and the high-energy peak to Fe xxvi Lyalpha emission. Then the inclination angle is even less, restricted to a few degrees. However, the radial emissivity law is allowed to be steeper (similar tor(-2.5)), and the outer radius does not have to be fine-tuned. Yet another scenario is that the lower energy peak originates in a disk but the higher energy peak originates in more distant matter. The disk inclination angle is then intermediate between the last two cases, but the emissivity is again required to be flat. We cannot rule out Fe xxv He-like absorption modifying the observed line profile. However, the data and the inferred emission-line parameters are insensitive to the presence of a Compton reflection continuum. Including Compton reflection does, however, allow a steeper radial emissivity law for the relativistic line. Future missions, such as Astro-E2, will be able to break a lot of the degeneracy in the physically distinct models that can all account for the Chandra data. Since IC 4329A is one of the brightest Seyfert 1 galaxies, it should be a good astrophysical laboratory for studying the ionization structure of accretion disks around supermassive black holes. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP McKernan, B (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RI XRAY, SUZAKU/A-1808-2009 NR 53 TC 17 Z9 17 U1 0 U2 1 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 2004 VL 608 IS 1 BP 157 EP 165 DI 10.1086/383261 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827EG UT WOS:000221881200014 ER PT J AU Naze, Y Manfroid, J Stevens, IR Corcoran, MF Flores, A AF Naze, Y Manfroid, J Stevens, IR Corcoran, MF Flores, A TI An x-ray investigation of the NGC 346 field in the small Magellanic Cloud. III. XMM-Newton data SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 346); Magellanic Clouds; X-rays : binaries; X-rays : individual ( NGC 346) ID SMC REGION; BINARIES; CATALOG; DISCOVERY; HD-5980; PULSAR; STARS AB We present new XMM-Newton results on the field around the NGC 346 star cluster in the SMC. This continues and extends previously published work on Chandra observations of the same field. The two XMM-Newton observations were obtained, respectively, 6 months before and 6 months after the previously published Chandra data. Of the 51 X-ray sources detected with XMM-Newton, 29 were already detected with Chandra. Comparing the properties of these X-ray sources in each of our three data sets has enabled us to investigate their variability on timescales of a year. Changes in the flux levels and/or spectral properties were observed for 21 of these sources. In addition, we discovered long-term variations in the X-ray properties of the peculiar system HD 5980, a luminous blue variable star that is likely to be a colliding wind binary system, which displayed the largest luminosity during the first XMM-Newton observation. C1 Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium. Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. Univ Space Res Assoc, Seabrook, MD 20706 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Naze, Y (reprint author), Univ Liege, Inst Astrophys & Geophys, 17 Allee 6 Aout,Bat B5c, B-4000 Liege, Belgium. EM naze@astro.ulg.ac.be; manfroid@astro.ulg.ac.be; irs@star.sr.bham.ac.uk; corcoran@barnegat.gsfc.nasa.gov; aflores@pampano.unacar.mx OI Naze, Yael/0000-0003-4071-9346 NR 28 TC 13 Z9 13 U1 0 U2 1 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 2004 VL 608 IS 1 BP 208 EP 219 DI 10.1086/386323 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827EG UT WOS:000221881200018 ER PT J AU Mehringer, DM Pearson, JC Keene, J Phillips, TG AF Mehringer, DM Pearson, JC Keene, J Phillips, TG TI Detection of vibrationally excited ethyl cyanide in the interstellar medium SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : abundances; ISM : clouds; ISM : individual (Sagittarius B2(N-LMH)); ISM : molecules; radio lines : ISM ID STAR-FORMING REGIONS; PROPIONITRILE C2H5CN; INTERNAL-ROTATION; SAGITTARIUS B2; LINE SURVEY; ORION-KL; MICROWAVE-SPECTRUM; OBSERVATIONAL DATA; COMPLEX-MOLECULES; GRAIN CHEMISTRY AB We have identified vibrationally excited CH3CH2CN (ethyl cyanide) for the first time in the interstellar medium. Using the Caltech Submillimeter Observatory, the Berkeley-Illinois-Maryland Association Array, and the Caltech Millimeter Array, we have detected several transitions from both the v(b) = 1 in-plane bending state and the v(t) = 1 torsional state in the Sgr B2(N-LMH) source. Because these excited states lie near 300 K above ground, vibrationally excited CH3CH2CN is potentially a useful probe of the hottest regions of dense, dusty molecular cloud cores where massive star formation is occurring. In addition, this identification will help account for many unidentified and misidentified spectral lines observed in hot molecular cores. C1 CALTECH 320 47, Caltech Submillimeter Observ, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mehringer, DM (reprint author), Univ Illinois, Natl Ctr Supercomp Applicat, 605 E Springfield Ave, Champaign, IL 61821 USA. NR 37 TC 21 Z9 21 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 2004 VL 608 IS 1 BP 306 EP 313 DI 10.1086/386357 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827EG UT WOS:000221881200026 ER PT J AU Stark, R Sandell, G Beck, SC Hogerheijde, MR van Dishoeck, EF van der Wal, P van der Tak, FFS Schafer, F Melnick, GJ Ashby, MLN de Lange, G AF Stark, R Sandell, G Beck, SC Hogerheijde, MR van Dishoeck, EF van der Wal, P van der Tak, FFS Schafer, F Melnick, GJ Ashby, MLN de Lange, G TI Probing the early stages of low-mass star formation in LDN 1689N: Dust and water in IRAS 16293-2422A, B, and E SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; ISM : clouds; ISM : individual (IRAS 16293-2422); ISM : jets and outflows; ISM : molecules; stars : formation ID SUBMILLIMETER CONTINUUM OBSERVATIONS; WAVE-ASTRONOMY-SATELLITE; CLERK-MAXWELL-TELESCOPE; MOLECULAR CLOUD CORES; YOUNG STELLAR OBJECTS; PROTOSTELLAR CORES; DEUTERATED WATER; BINARY-SYSTEM; DEUTERIUM FRACTIONATION; INTERSTELLAR-MOLECULES AB We present deep images of dust continuum emission at 450, 800, and 850 mum of the dark cloud LDN 1689N, which harbors the low-mass young stellar objects (YSOs) IRAS 16293-2422 A and B (I16293A and I16293B) and the cold prestellar object I16293E. Toward the positions of I16293A and I16293E we also obtained spectra of CO-isotopomers and deep submillimeter observations of chemically related molecules with high critical densities (HCO+, (HCO+)-C-13, DCO+, H2O, HDO, and H2D+). Toward I16293A we report the detection of the HDO 1(01)-0(00) and H2O 1(10-)1(01) ground-state transitions as broad self-reversed emission profiles with narrow absorption and a tentative detection of H2D+ 1(10)-1(11). Toward I16293E we detect weak emission of subthermally excited HDO 1(01)-0(00). Based on this set of submillimeter continuum and line data, we model the envelopes around I16293A and I16293E. The density and velocity structure of I16293A is fitted by an inside-out collapse model, yielding a sound speed of a 0: 7 kms(-1), an age of t = (0.6-2.5) x 10(4) yr, and amass of 6.1 M.. The density in the envelope of I16293E is fitted by a radial power law with index -1.0 +/- 0.2, a mass of 4.4 M., and a constant temperature of 16 K. These respective models are used to study the chemistry of the envelopes of these pre- and protostellar objects. We made a large, fully sampled CO J = 2-1 map of LDN 1689N, which clearly shows the two outflows from I16293A and I16293B and the interaction of one of the flows with I16293E. An outflow from I16293E reported elsewhere is not confirmed. Instead, we find that the motions around I16293E identified from small maps are part of a larger scale fossil flow from I16293B. Modeling of the I16293A outflow shows that the broad HDO, water ground state, and CO J = 6-5 and 7-6 emission lines originate in this flow, while the HDO and H2O line cores originate in the envelope. The narrow absorption feature in the ground-state water lines is due to cold gas in the outer envelope. The derived H2O abundance is 3 x 10(-9) in the cold regions of the envelope of I16293A (T-kin < 14 K), 2 x 10(-7) in warmer regions of the envelope (> 14 K), and 10(-8) in the outflow. The HDO abundance is constant at a few times 10(-10) throughout the envelopes of I16293A and I16293E. Because the derived H2O and HDO abundances in the two objects can be understood through shock chemistry in the outflow and ion-molecule chemistry in the envelopes, we argue that both objects are related in chemical evolution. The [HDO]/[H2O] abundance ratio in the warm inner envelope of I16293A of a few times 10(-4) is comparable to that measured in comets. This supports the idea that the [HDO]/[ H2O] ratio is determined in the cold prestellar core phase and conserved throughout the formation process of low-mass stars and planets. C1 Max Planck Inst Radioastron, D-53121 Bonn, Germany. Sterrewacht Leiden, NL-2300 RA Leiden, Netherlands. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Tel Aviv Univ, Dept Phys & Astron, Ramat Aviv, Israel. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Groningen, SRON, NL-9700 AV Groningen, Netherlands. RP Stark, R (reprint author), Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany. NR 95 TC 70 Z9 70 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 2004 VL 608 IS 1 BP 341 EP 364 DI 10.1086/392492 PN 1 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827EG UT WOS:000221881200030 ER PT J AU Laughlin, G Steinacker, A Adams, FC AF Laughlin, G Steinacker, A Adams, FC TI Type I planetary migration with MHD turbulence SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; planetary systems; planetary systems : formation; planets and satellites : formation; turbulence ID 3-DIMENSIONAL MAGNETOHYDRODYNAMIC SIMULATIONS; ANGULAR-MOMENTUM TRANSPORT; PROTOSTELLAR DISKS; ACCRETION DISK; GIANT PLANET; COMPANION; TORQUES; NEBULA; MODELS; STAR AB This paper examines how type I planetary migration is affected by the presence of turbulent density fluctuations in the circumstellar disk. For type I migration, the planet does not clear a gap in the disk and its secular motion is driven by torques generated by the wakes it creates in the surrounding disk fluid. MHD turbulence creates additional density perturbations that gravitationally interact with the planet and can dominate the torques that stem from the protoplanetary wake. This paper shows that conventional type I migration can be readily overwhelmed by turbulent perturbations, and hence the usual description of type I migration should be modified in locations where the magnetorotational instability is active. In general, the migrating planet does not follow a smooth inward trend but rather exhibits a random walk through phase space. Our main conclusion is that MHD turbulence will alter the timescales for type I planetary migration and, because of chaos, requires the timescales to be described by a distribution of values. C1 Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Michigan, Michigan Ctr Theoret Phys, Ann Arbor, MI 48109 USA. RP Laughlin, G (reprint author), Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. NR 28 TC 106 Z9 107 U1 0 U2 1 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 2004 VL 608 IS 1 BP 489 EP 496 DI 10.1086/386316 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827EG UT WOS:000221881200043 ER PT J AU Birch, AC Kosovichev, AG Duvall, TL AF Birch, AC Kosovichev, AG Duvall, TL TI Sensitivity of acoustic wave travel times to sound-speed perturbations in the solar interior SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : helioseismology; Sun : interior; Sun : oscillations waves ID DISTANCE HELIOSEISMOLOGY; KERNELS AB For time-distance helioseismology, it is important to establish the relationship between the travel times of acoustic waves propagating between different points on the solar surface through the solar interior and local perturbations to the sound speed in the propagation region. We use the Born approximation to derive a general expression for the linear sensitivity of travel times to local sound-speed perturbations in plane-parallel solar models with stochastic wave sources. The results show that the sensitivity of time-distance measurements to perturbations in sound speed depends on the details of the measurement procedure, such as the phase-speed filter used in typical time-distance data analysis. As a result, the details of the measurement procedure should be taken into account in the inversion of time-distance data. Otherwise, the inferred depths of perturbations may be incorrect. C1 Stanford Univ, WW Hansen Expt Lab, Stanford, CA 94305 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Birch, AC (reprint author), Stanford Univ, WW Hansen Expt Lab, Stanford, CA 94305 USA. RI Duvall, Thomas/C-9998-2012 NR 29 TC 58 Z9 58 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 2004 VL 608 IS 1 BP 580 EP 600 DI 10.1086/386361 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827EG UT WOS:000221881200051 ER PT J AU Glinski, RJ Ford, BJ Harris, WM Anderson, CM Morgenthaler, JP AF Glinski, RJ Ford, BJ Harris, WM Anderson, CM Morgenthaler, JP TI Oxygen/hydrogen chemistry in the inner comae of active comets SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; comets : general ID O1 HALE-BOPP; PARTICLE-TRAJECTORY MODELS; HYAKUTAKE C/1996 B2; LYMAN-ALPHA COMA; PLANETARY-ATMOSPHERES; DENSITY DISTRIBUTION; NEUTRAL COMPOUNDS; CARBON-MONOXIDE; ION COMPOSITION; IKEYA-ZHANG AB We have constructed a concentric-shell, one-dimensional kinetic model that examines the chemistry of hydrogen and oxygen species in detail. We have studied the effects of the reactions of the reactive OH, O(P-3), and O(D-1) species with themselves and with the abundant stable molecules in the inner coma of moderately and highly active comets. We find that the reactions (1) O(D-1) + H2O --> 2OH and (2) O(P-3) + OH --> O-2+H play important roles in the inner comae of active comets. Inclusion of reaction ( 2) predicts the formation of significant amounts of molecular oxygen. As the densities of O-2 may be as high as 1% those of water in some cases, the possibility of detection exists. We suggest the possibility that the ion O-2(+) may contribute to some previously unassigned features in the optical ion-tail spectra of comets. We also consider the role that reactions of the reactive species might play in the destruction of CO, NH3, and organic molecules in the inner coma of the active comet. We find that destruction of formaldehyde, for example, by reaction with OH has a small but essentially negligible effect on the predicted production rate of formaldehyde. Finally, we examine the significance of the reaction of OH with CO in the dense inner coma. C1 Tennessee Technol Univ, Dept Chem, Cookeville, TN 38505 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Glinski, RJ (reprint author), Tennessee Technol Univ, Dept Chem, Cookeville, TN 38505 USA. EM rglinski@tntech.edu NR 57 TC 6 Z9 6 U1 0 U2 1 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 2004 VL 608 IS 1 BP 601 EP 609 DI 10.1086/379762 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827EG UT WOS:000221881200052 ER PT J AU de Mello, DF Daddi, E Renzini, A Cimatti, A Alighieri, SD Pozzetti, L Zamorani, G AF de Mello, DF Daddi, E Renzini, A Cimatti, A Alighieri, SD Pozzetti, L Zamorani, G TI Metal enrichment in near-infrared luminous galaxies at z similar to 2: Signatures of proto-elliptical galaxies? SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : formation; galaxies : high-redshift; galaxies : starburst ID LYMAN BREAK GALAXIES; STAR-FORMING GALAXIES; REDSHIFT; SPECTRA; EXTINCTION AB We present the analysis of the co-added rest-frame UV spectrum (1200 Angstrom < z < 2000 Angstrom) of five K-luminous galaxies at z similar to2 from the K20 survey. The composite spectrum is characterized by strong absorption lines over the UV continuum from C, N, O, Al, Si, and Fe in various ionization stages. While some of these lines are interstellar, several among the strongest absorptions are identified with stellar photospheric lines. Most of the photospheric and interstellar features are stronger in the K-luminous composite spectrum than in Lyman break galaxies at z similar to3. This suggests higher metallicity and possibly also larger interstellar velocity dispersion caused by macroscopic motions. The absorption lines and the slope of the UV continuum are well matched by the spectrum of the nearby luminous infrared galaxy NGC 6090, which is in the process of merging. A metallicity higher than solar is suggested by comparing the pure photospheric lines (Si III, C III, and Fe v) with starburst models. The evidence of high metallicity, together with the high masses, high star formation rates, and possibly strong clustering, well qualify these galaxies as progenitors of local massive elliptical galaxies. C1 NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. ESO, D-85748 Garching, Germany. INAF, Osservatorio Astron Arcetri, I-50125 Florence, Italy. INAF, Osservatorio Astron Bologna, I-4027 Bologna, Italy. RP de Mello, DF (reprint author), NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. RI Daddi, Emanuele/D-1649-2012; di Serego Alighieri, Sperello/E-4067-2010; OI Daddi, Emanuele/0000-0002-3331-9590; di Serego Alighieri, Sperello/0000-0001-8769-2692; Pozzetti, Lucia/0000-0001-7085-0412 NR 18 TC 23 Z9 23 U1 0 U2 1 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 2004 VL 608 IS 1 BP L29 EP L32 DI 10.1086/422139 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827EJ UT WOS:000221881600008 ER PT J AU Strohmayer, TE AF Strohmayer, TE TI Detection of nitrogen and neon in the X-ray spectrum of GP Comae berenices with XMM/Newton SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : general; novae, cataclysmic variables; stars : individual (GP Comae Berenices); white dwarfs; X-rays : binaries; X-rays : stars ID DISK BOUNDARY-LAYERS; CATACLYSMIC VARIABLES; ACCRETION DISK; LOW-MASS; EMISSION; STARS; BINARIES; SOLAR AB We report on X-ray spectroscopic observations with XMM/Newton of the ultracompact, double white dwarf binary GP Com. With the Reflection Grating Spectrometers (RGSs), we detect the Lyalpha and Lybeta lines of hydrogen-like nitrogen (N VII) and neon (Ne x), as well as the helium-like triplets (N VI and Ne IX) of these same elements. All the emission lines are unresolved. These are the first detections of X-ray emission lines from a double-degenerate, AM CVn system. We detect the resonance (r) and intercombination (i) lines of the N vi triplet, but not the forbidden (f) line. The implied line ratios for N VI, R = f/i < 0.3 and G = (f + i)/r &AP; 1 combined with the strong resonance line are consistent with formation in a dense, collision-dominated plasma. Both the RGS and EPIC/MOS spectra are well fitted by emission from an optically thin thermal plasma with an emission measure proportional to (kT/6.5 keV)(0.8) (model cevmkl in XSPEC). Helium, nitrogen, oxygen, and neon are required to adequately model the spectrum; however, the inclusion of sulphur and iron further improves the fit, suggesting that these elements may also be present at low abundance. We confirm in the X-rays the underabundance of both carbon and oxygen relative to nitrogen, first deduced from optical spectroscopy by Marsh et al. The average X-ray luminosity of &AP;3 x 10(30) ergs s(-1) implies a mass accretion rate m &AP; 9 x 10(-13) M. yr(-1). The implied temperature and density of the emitting plasma, combined with the presence of narrow emission lines and the low-m value, are consistent with production of the X-ray emission in an optically thin boundary layer just above the. m surface of the white dwarf. C1 NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Strohmayer, TE (reprint author), NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. EM stroh@clarence.gsfc.nasa.gov NR 32 TC 13 Z9 13 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 10 PY 2004 VL 608 IS 1 BP L53 EP L56 DI 10.1086/422192 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827EJ UT WOS:000221881600014 ER PT J AU Wang, JX Rhoads, JE Malhotra, S Dawson, S Stern, D Dey, A Heckman, TM Norman, CA Spinrad, H AF Wang, JX Rhoads, JE Malhotra, S Dawson, S Stern, D Dey, A Heckman, TM Norman, CA Spinrad, H TI X-ray nondetection of the Ly alpha emitters at z similar to 4.5 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : high-redshift; galaxies : starburst; X-rays : galaxies ID SUBARU DEEP SURVEY; WIDE-FIELD SURVEY; LUMINOSITY FUNCTION; SEYFERT-GALAXIES; YOUNG GALAXIES; TYPE-2 QSO; DISCOVERY; EMISSION; QUASARS; SEARCH AB The Lyalpha emitters found at z similar to 4.5 by the Large Area Lyman Alpha (LALA) survey have high equivalent widths in the Lya line, which can be produced by either narrow-lined active galactic nuclei (AGNs) or by stellar populations with a very high proportion of young, massive stars. To investigate the AGN scenario, we obtained two deep Chandra exposures to study the X-ray nature of the Lyalpha emitters. The 172 ks deep Chandra image on the LALA Bootes field was presented in a previous paper, and in this Letter we present a new Chandra deep exposure (174 ks) on the LALA Cetus field, which doubled our sample of X-ray-imaged Lyalpha sources and imaged the brightest source among our Lyalpha emitters. None of the 101 Lyalpha sources covered by two Chandra exposures were detected individually in X-rays, with a 3 sigma limiting X-ray flux of F0.5-10.0 keV < 3.3 x 10(-16) ergs cm(-2) s(-1) for on-axis targets. The sources remain undetectable in the stacked image, implying a 3 σ limit to the average luminosity of L2-8 keV < 2.8 x 10(42) ergs s(-1). The resulting X-ray to Lyalpha ratio is greater than 21 times lower than the ratios for known high- redshift type II quasars. Together with optical spectra obtained at Keck, we conclude that no evidence of AGN activity was found among our Lyalpha emitters at z similar to 4.5. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Opt Astron Observ, Tucson, AZ 85719 USA. RP Wang, JX (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. EM jxw@pha.jhu.edu; rhoads@stsci.edu; san@stsci.edu; sdawson@astron.berkeley.edu; stern@zwolfkinder.jpl.nasa.gov; dey@noao.edu; heckman@pha.jhu.edu; norman@stsci.edu; spinrad@astro.berkeley.edu NR 35 TC 55 Z9 55 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 10 PY 2004 VL 608 IS 1 BP L21 EP L24 DI 10.1086/422311 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827EJ UT WOS:000221881600006 ER PT J AU Sulima, OV Refaat, TE Mauk, MG Cox, JA Li, J Lohokare, SK Abedin, MN Singh, UN Rand, JA AF Sulima, OV Refaat, TE Mauk, MG Cox, JA Li, J Lohokare, SK Abedin, MN Singh, UN Rand, JA TI AlGaAsSb/InGaAsSb phototransistors for spectral range around 2 mu m SO ELECTRONICS LETTERS LA English DT Article AB The first AlGaAsSb/InGaAsSb phototransistors sensitive in the 2.0-2.1 mum spectral range are reported. These phototransistors exhibited both high gain and relatively low noise, and a record 2 mum detectivity of 3.9 x 10(11) cmHz(1/2)/W was obtained at -20degreesC, which is equivalent to a noise-equivalent-power of 4.6 x 10(-14) W/Hz(1/2). C1 AstroPower Inc, Newark, DE 19716 USA. Sci & Technol Corp, Hampton, VA 23666 USA. Univ Illinois, Dept Elect & Comp Engn, Urbana, IL 61801 USA. Univ Delaware, Dept Elect & Comp Engn, Newark, DE 19716 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Sulima, OV (reprint author), AstroPower Inc, Solar Pk, Newark, DE 19716 USA. EM sulima@astropower.com RI Li, Jian/B-1627-2016 NR 5 TC 13 Z9 13 U1 0 U2 3 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD JUN 10 PY 2004 VL 40 IS 12 BP 766 EP 767 DI 10.1049/el:20040422 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA 834BI UT WOS:000222386200037 ER PT J AU Wahr, J Swenson, S Zlotnicki, V Velicogna, I AF Wahr, J Swenson, S Zlotnicki, V Velicogna, I TI Time-variable gravity from GRACE: First results SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CLIMATE EXPERIMENT GRACE; RECOVERY AB Eleven monthly GRACE gravity field solutions are now available for analyses. We show those fields can be used to recover monthly changes in water storage, both on land and in the ocean, to accuracies of 1.5 cm of water thickness when smoothed over 1000 km. The amplitude of the annually varying signal can be determined to 1.0 cm. Results are 30% better for a 1500 km smoothing radius, and 40% worse for a 750 km radius. We estimate the annually varying component of water storage for three large drainage basins (the Mississippi, the Amazon, and a region draining into the Bay of Bengal), to accuracies of 1.0-1.5 cm. C1 Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Univ Colorado, CIRES, Boulder, CO 80309 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wahr, J (reprint author), Univ Colorado, Dept Phys, Boulder, CO 80309 USA. EM wahr@lemond.colorado.edu NR 10 TC 333 Z9 361 U1 12 U2 49 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 9 PY 2004 VL 31 IS 11 AR L11501 DI 10.1029/2004GL019779 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 829XJ UT WOS:000222084600002 ER PT J AU Pines, V Zlatkowski, M Chait, A AF Pines, V Zlatkowski, M Chait, A TI Postnucleation droplet growth in supersaturated gas with arbitrary vapor concentration SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID WATER AB This work concerns the reexamination and extension of the current theory of phase transition dynamics for liquid droplets growing on soluble aerosols from a supersaturated gas mixture for the general case of arbitrary value of vapor concentration. We found that the inconsistency in the common treatment of the vapor diffusion, due to an implicit assumption of the constancy of gas density in the vicinity of a droplet by neglecting its dependency on temperature and vapor concentration, leads to the obvious discrepancy in the Maxwell expression for the growth rate regarding droplets of near critical size. Restoring the correct treatment of the vapor diffusion in terms of the mass concentration of water vapor and taking into the consideration variations of gas density in the vicinity of a droplet in compliance with the equation of state of moist air, we have obtained a new expression for the droplet growth rate valid for an arbitrary value of vapor concentration. The limitations imposed by the molecular kinetic fluxes to postnucleation diffusional growth of small droplets with a large Knudsen number are also reevaluated to include previously neglected physical effects. In particular, the essential contribution of the vapor molecular energy flux into the total kinetic molecular heat flux as well as the temperature variations of mean thermal velocities of air and vapor molecules in the vicinity of the droplet interface have been taken into consideration. Surprisingly significant differences have been found in new expressions derived for the droplet growth rate and droplet temperature, even in the limit of small vapor concentration, if comparing with commonly used results. These findings could help with better interpretation of experimental measurements to infer more reliable data for the mass and thermal accommodations coefficients. (C) 2004 American Institute of Physics. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Case Western Reserve Univ, Dept Phys, Cleveland, OH 44135 USA. RP Chait, A (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM arnon.chait@grc.nasa.gov NR 17 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 8 PY 2004 VL 120 IS 22 BP 10455 EP 10469 DI 10.1063/1.1738107 PG 15 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 822KM UT WOS:000221538200014 PM 15268074 ER PT J AU Wu, ZH Huang, NE AF Wu, ZH Huang, NE TI A study of the characteristics of white noise using the empirical mode decomposition method SO PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article DE empirical mode decomposition; intrinsic mode function; characteristics of white noise; energy-density function; energy-density spread function; statistical significance test ID HILBERT SPECTRUM; TIME-SERIES AB Based on numerical experiments on white noise using the empirical mode decomposition (EMD) method, we find empirically that the EMD is effectively a dyadic filter., the intrinsic mode function (IMF) components are all normally distributed, and the Fourier spectra of the IMF components are all identical and cover the same area, on a semi-logarithmic period scale. Expanding from these empirical findings, we further deduce that the product of the energy density of IMF and its corresponding averaged period is a constant, and that the energy-density function is chi-squared distributed. Furthermore, we derive the energy-density spread function of the IMF components. Through these results, we establish a, method of assigning statistical significance of information content for IMF components from any noisy data. Southern Oscillation Index data, are used to illustrate the methodology developed here. C1 Ctr Ocean Land Atmosphere Studies, Beltsville, MD 20705 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Oceans & Ice Branch, Greenbelt, MD 20771 USA. RP Ctr Ocean Land Atmosphere Studies, Suite 302,4041 Powder Mill Rd, Beltsville, MD 20705 USA. EM zhwu@cola.iges.org RI Wu, Zhaohua/N-7102-2013; OI Wu, Zhaohua/0000-0003-1660-0724 NR 8 TC 612 Z9 757 U1 14 U2 110 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-5021 EI 1471-2946 J9 P ROY SOC A-MATH PHY JI Proc. R. Soc. A-Math. Phys. Eng. Sci. PD JUN 8 PY 2004 VL 460 IS 2046 BP 1597 EP 1611 DI 10.1098/rspa.2003.1221 PG 15 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 825YP UT WOS:000221795400003 ER PT J AU Sherwood, SC Chae, JH Minnis, P McGill, M AF Sherwood, SC Chae, JH Minnis, P McGill, M TI Underestimation of deep convective cloud tops by thermal imagery SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TROPICAL TROPOPAUSE; SATELLITE AB The most common method of ascertaining cloud heights from space is from thermal brightness temperatures. Deep convective clouds of high water content are expected to radiate as black bodies. Here, thermal cloud top estimates from GOES-8 are compared with direct estimates of where the top should be sensed, based on colocated Goddard Cloud Physics Lidar (CPL) observations collected during the Cirrus Regional Study of Tropical Anvils and Florida Area Cirrus Experiment (CRYSTAL-FACE). GOES-8 cloud top heights are consistently similar to1 km lower than the "visible'' cloud top estimates from the lidar, even though the latter take into account the finite visible opacity of the clouds and any overlying thin cirrus layers, and are often far below the position of highest detected cloud. The low bias in thermal estimates appears to get worse for the tallest clouds, perhaps by an additional kilometer, and depends little on cloud albedo. The consistency of the bias over multiple satellites suggests that cloud retrievals are affected by an unexpected radiative transfer issue. C1 Yale Univ, Dept Geol & Geophys, New Haven, CT 06520 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Sherwood, SC (reprint author), Yale Univ, Dept Geol & Geophys, POB 6666, New Haven, CT 06520 USA. EM ssherwood@alum.mit.edu RI Chae, Jung Hyo/E-5296-2010; Sherwood, Steven/B-5673-2008; McGill, Matthew/D-8176-2012; Minnis, Patrick/G-1902-2010 OI Sherwood, Steven/0000-0001-7420-8216; Minnis, Patrick/0000-0002-4733-6148 NR 18 TC 72 Z9 72 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 4 PY 2004 VL 31 IS 11 AR L11102 DI 10.1029/2004GL019699 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 828DG UT WOS:000221952600004 ER PT J AU Leblanc, T McDermid, IS Hauchecorne, A AF Leblanc, T McDermid, IS Hauchecorne, A TI A study of ozone variability and its connection with meridional transport in the northern Pacific lower stratosphere during summer 2002 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE ozone transport; lower stratosphere; tropopause ID QUASI-BIENNIAL OSCILLATION; TROPICAL UPPER TROPOSPHERE; ISENTROPIC TRANSPORT; MASS-EXCHANGE; MAUNA-LOA; CLIMATOLOGY; LIDAR; TRAJECTORIES; INTRUSIONS; TROPOPAUSE AB [ 1] A preliminary study of the impact of the north-central Pacific circulation in the subtropical stratosphere on ozone variability locally observed by lidar is presented. The results from the upper tropospheric and stratospheric ozone measurements of the Jet Propulsion Laboratory lidars located at Mauna Loa Observatory ( MLO), Hawaii, and Table Mountain Facility ( TMF), California, during summer 2002 were compared to isentropic potential vorticity ( IPV) advected on 54 levels from 320 to 1500 K by the high-resolution model MIMOSA. The correlation between ozone measured by lidar, and the origin of the 10-day backward trajectories of the air parcels sampled, was also investigated. Near the tropopause, strong positive correlation between ozone mixing ratio and IPV was observed at both MLO and TMF lidar sites. The largest fluctuations were centered near 350 K and are associated with the meridional displacement of the tropopause by Rossby waves north or south of the observing sites. These large displacements were occasionally accompanied by Rossby wave breaking ( RWB), as was identified several times during the summer in the vicinity of the Hawaiian Islands. Using IPV maps, a case study of the 13 July event is briefly presented. This event appears to be typical of breaking events previously investigated at midlatitudes, including the southward intrusion of high-PV air originating in the high-latitude lower stratosphere. This time the intrusion was observed to extend deep in the subtropics. Strong positive ozone anomalies were simultaneously measured by the MLO lidar. Positive correlation between ozone and the equivalent latitude averaged along the parcels' trajectories was seen up to 475 K in the stratosphere. At and above 750 K, negative correlation was calculated for both TMF and MLO. For TMF the altitude dependence of the correlation is similar to that already observed for summer and winter midlatitudes For MLO the observed negative correlation was found to be the result of opposite seasonal and interannual tendencies in ozone and equivalent latitude throughout the summer. All other correlations are associated with a higher intraseasonal variability of both ozone and the parcels' origin, as compared to their seasonal tendencies. C1 CALTECH, Jet Prop Lab, Table Mt Facil, Wrightwood, CA 92397 USA. CNRS, Serv Aeron, F-91371 Verrieres Le Buisson, France. RP Leblanc, T (reprint author), CALTECH, Jet Prop Lab, Table Mt Facil, Wrightwood, CA 92397 USA. EM leblanc@tmf.jpl.nasa.gov RI Hauchecorne, Alain/A-8489-2013; OI Hauchecorne, Alain/0000-0001-9888-6994 NR 42 TC 3 Z9 3 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 4 PY 2004 VL 109 IS D11 AR D11105 DI 10.1029/2003JD004027 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 828DO UT WOS:000221953500001 ER PT J AU Wilson, EH Atreya, SK AF Wilson, EH Atreya, SK TI Current state of modeling the photochemistry of Titan's mutually dependent atmosphere and ionosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Review DE Titan; photochemistry; composition; haze; ion chemistry; planetary atmospheres ID PHOTOABSORPTION CROSS-SECTIONS; THERMAL RATE CONSTANTS; TEMPERATURE RATE COEFFICIENTS; ELECTRON-IMPACT IONIZATION; ABSOLUTE RATE-CONSTANT; ETHYNYL RADICAL C2H; SUBMILLIMETER HETERODYNE OBSERVATIONS; VOYAGER INFRARED OBSERVATIONS; OPTICAL OSCILLATOR-STRENGTHS; CHEMICAL KINETIC DATABASE AB In the context of recent observations, microphysical models, and laboratory data, a photochemical model of Titan's atmosphere, including updated chemistry focusing on rate coefficients and cross sections measured under appropriate conditions, has been developed to increase understanding of these processes and improve upon previous Titan photochemical models. The model employs a two-stream discrete ordinates method to characterize the transfer of solar radiation, and the effects of electron-impact, cosmic-ray deposition, and aerosol opacities from fractal and Mie particles are analyzed. Sensitivity studies demonstrate that an eddy diffusion profile with a homopause level of 850 km and a methane stratospheric mole fraction of 2.2% provides the best fit of stratospheric and upper atmosphere observations and an improved fit over previous Titan photochemical models. Lack of fits for C3H8, HC3N, and possibly C2H3CN can be resolved with adjustments in aerosol opacity. The model presents a benzene profile consistent with its detection in Titan's stratosphere [Coustenis et al., 2003], which may play an important role in the formation of Titan hazes. An electron peak concentration of 4200 cm(-3) is calculated, which exceeds observations by 20%, considerably lower than previous ionosphere models. With adjustments in aerosol opacities and surface fluxes the model illustrates that reasonable fits to existing observations are possible with a single eddy diffusion profile, contrary to the conclusions of previous Titan models. These results will aid in the receipt and interpretation of data from Cassini-Huygens, which will arrive at Titan in 2004 and deploy a probe into Titan's atmosphere in January 2005. C1 NASA, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. RP Wilson, EH (reprint author), NASA, Jet Prop Lab, 4800 Oak Grove Dr,M-S 169-237, Pasadena, CA 91109 USA. EM eric.wilson@jpl.nasa.gov NR 320 TC 257 Z9 258 U1 6 U2 36 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUN 4 PY 2004 VL 109 IS E6 AR E06002 DI 10.1029/2003JE002181 PG 39 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 828EE UT WOS:000221955500001 ER PT J AU Altfeder, IB Liang, X Yamada, T Chen, DM Narayanamurti, V AF Altfeder, IB Liang, X Yamada, T Chen, DM Narayanamurti, V TI Anisotropic metal-insulator transition in epitaxial thin films SO PHYSICAL REVIEW LETTERS LA English DT Article ID SURFACE; INDIUM; WAVES; STATE AB By comparing the properties of In and Pb quantum wells in a scanning tunneling microscopy subsurface imaging experiment, we found the existence of lateral bound states, a 2D Mott-Hubbard correlation gap, induced by transverse confinement. Its formation is attributed to spin or charge overscreening of quasi-2D excitations. The signature of the 2D confinement-deconfinement transition is also experimentally observed, with the correlation gap being pinned in the middle of the conduction band. A self-organized 2D Anderson lattice is suggested as a new ground state. C1 Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Harvard Univ, Rowland Inst, Cambridge, MA 02142 USA. Chinese Acad Sci, Inst Phys, Beijing 100080, Peoples R China. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. RI Yamada, Toshishige/E-7834-2012 OI Yamada, Toshishige/0000-0001-7145-9212 NR 23 TC 19 Z9 19 U1 2 U2 10 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 4 PY 2004 VL 92 IS 22 AR 226404 DI 10.1103/PhysRevLett.92.226404 PG 4 WC Physics, Multidisciplinary SC Physics GA 826QU UT WOS:000221844400044 PM 15245244 ER PT J AU Blake, NJ Streets, DG Woo, JH Simpson, IJ Green, J Meinardi, S Kita, K Atlas, E Fuelberg, HE Sachse, G Avery, MA Vay, SA Talbot, RW Dibb, JE Bandy, AR Thornton, DC Rowland, FS Blake, DR AF Blake, NJ Streets, DG Woo, JH Simpson, IJ Green, J Meinardi, S Kita, K Atlas, E Fuelberg, HE Sachse, G Avery, MA Vay, SA Talbot, RW Dibb, JE Bandy, AR Thornton, DC Rowland, FS Blake, DR TI Carbonyl sulfide and carbon disulfide: Large-scale distributions over the western Pacific and emissions from Asia during TRACE-P SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE carbonyl sulfide (OCS); carbon disulfide (CS2); Asian emissions; emission inventories ID DIMETHYL SULFIDE; AIRCRAFT OBSERVATIONS; CHEMICAL EVOLUTION; TRANSPORT PATHWAYS; GLOBAL SOURCES; SOUTH-PACIFIC; SULFUR CYCLE; BIOMASS; ATMOSPHERE; OUTFLOW AB An extensive set of carbonyl sulfide (OCS) and carbon disulfide (CS2) observations were made as part of the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) project, which took place in the early spring 2001. TRACE-P sampling focused on the western Pacific region but in total included the geographic region 110degreesE to 290degreesE longitude, 5degreesN to 50degreesN latitude, and 0-12 km altitude. Substantial OCS and CS2 enhancements were observed for a great many air masses of Chinese and Japanese origin during TRACE-P. Over the western Pacific, mean mixing ratios of long-lived OCS and shorter-lived CS2 showed a gradual decrease by about 10% and a factor of 5-10, respectively, from the surface to 8-10 km altitude, presumably because land-based sources dominated their distribution during February through April 2001. The highest mean OCS and CS2 levels (580 and 20 pptv, respectively, based on 2.5degrees x 2.5degrees latitude bins) were observed below 2 km near the coast of Asia, at latitudes between 25degreesN and 35degreesN, where urban Asian outflow was strongest. Ratios of OCS versus CO for continental SE Asia were much lower compared to Chinese and Japanese signatures and were strongly associated with biomass burning/biofuel emissions. We present a new inventory of anthropogenic Asian emissions ( including biomass burning) for OCS and CS2 and compare it to emission estimates based on regional relationships of OCS and CS2 to CO and CO2. The OCS and CS2 results for the two methods compare well for continental SE Asia and Japan plus Korea and also for Chinese CS2 emissions. However, it appears that the inventory underestimates Chinese emissions of OCS by about 30-100%. This difference may be related to the fact that we did not include natural sources such as wetland emissions in our inventory, although the contributions from such sources are believed to be at a seasonal low during the study period. Uncertainties in OCS emissions from Chinese coal burning, which are poorly characterized, likely contribute to the discrepancy. C1 Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Iowa, Iowa Adv Technol Labs, Ctr Global & Reg Environm Res, Iowa City, IA 52242 USA. Ibaraki Univ, Fac Sci, Dept Environm Sci, Mito, Ibaraki 3108512, Japan. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ New Hampshire, Climate Change Res Ctr, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Drexel Univ, Dept Chem, Philadelphia, PA 19104 USA. RP Univ Calif Irvine, Dept Chem, 516 Rowland Hall, Irvine, CA 92697 USA. EM nblake@uci.edu; dstreets@anl.gov; woojh21@cgrer.uiowa.edu; isimpson@uci.edu; jegreen@caltech.edu; smeinard@uci.edu; kita@mx.ibaraki.ac.jp; atlas@ucar.edu; fuelberg@huey.met.fsu.edu; g.w.sachse@larc.nasa.gov; m.a.avery@larc.nasa.gov; s.a.vay@larc.nasa.gov; robert.talbot@unh.edu; jack.dibb@unh.edu; bandyar@drexel.edu; dct@drexel.edu; rowland@uci.edu; drblake@uci.edu RI Atlas, Elliot/J-8171-2015; OI Streets, David/0000-0002-0223-1350 NR 50 TC 29 Z9 29 U1 2 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 3 PY 2004 VL 109 IS D15 AR D15S05 DI 10.1029/2003JD004259 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 828DT UT WOS:000221954000003 ER PT J AU Singh, HB Salas, LJ Chatfield, RB Czech, E Fried, A Walega, J Evans, MJ Field, BD Jacob, DJ Blake, D Heikes, B Talbot, R Sachse, G Crawford, JH Avery, MA Sandholm, S Fuelberg, H AF Singh, HB Salas, LJ Chatfield, RB Czech, E Fried, A Walega, J Evans, MJ Field, BD Jacob, DJ Blake, D Heikes, B Talbot, R Sachse, G Crawford, JH Avery, MA Sandholm, S Fuelberg, H TI Analysis of the atmospheric distribution, sources, and sinks of oxygenated volatile organic chemicals based on measurements over the Pacific during TRACE-P SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE oxygenated organics; PANs; acetone ID SOUTHEASTERN UNITED-STATES; PONDEROSA PINE PLANTATION; IN-SITU MEASUREMENTS; AIR-SEA EXCHANGE; UPPER TROPOSPHERE; NONMETHANE HYDROCARBONS; CARBONYL-COMPOUNDS; COMPOUND EMISSIONS; LOWER STRATOSPHERE; HYDROGEN-PEROXIDE AB Airborne measurements of a large number of oxygenated volatile organic chemicals (OVOC) were carried out in the Pacific troposphere (0.1-12 km) in winter/spring of 2001 ( 24 February to 10 April). Specifically, these measurements included acetone (CH3COCH3), methylethyl ketone (CH3COC2H5, MEK), methanol (CH3OH), ethanol (C2H5OH), acetaldehyde (CH3CHO), propionaldehyde (C2H5CHO), peroxyacylnitrates (PANs) (CnH2n+1COO2NO2), and organic nitrates (CnH2n+1ONO2). Complementary measurements of formaldehyde (HCHO), methyl hydroperoxide (CH3OOH), and selected tracers were also available. OVOC were abundant in the clean troposphere and were greatly enhanced in the outflow regions from Asia. Background mixing ratios were typically highest in the lower troposphere and declined toward the upper troposphere and the lowermost stratosphere. Their total abundance (SigmaOVOC) was nearly twice that of nonmethane hydrocarbons (SigmaC(2)-C-8 NMHC). Throughout the troposphere, the OH reactivity of OVOC is comparable to that of methane and far exceeds that of NMHC. A comparison of these data with western Pacific observations collected some 7 years earlier (February-March 1994) did not reveal significant differences. Mixing ratios of OVOC were strongly correlated with each other as well as with tracers of fossil and biomass/biofuel combustion. Analysis of the relative enhancement of selected OVOC with respect to CH3Cl and CO in 12 plumes originating from fires and sampled in the free troposphere (3-11 km) is used to assess their primary and secondary emissions from biomass combustion. The composition of these plumes also indicates a large shift of reactive nitrogen into the PAN reservoir thereby limiting ozone formation. A three-dimensional global model that uses state of the art chemistry and source information is used to compare measured and simulated mixing ratios of selected OVOC. While there is reasonable agreement in many cases, measured aldehyde concentrations are significantly larger than predicted. At their observed levels, acetaldehyde mixing ratios are shown to be an important source of HCHO (and HOx) and PAN in the troposphere. On the basis of presently known chemistry, measured mixing ratios of aldehydes and PANs are mutually incompatible. We provide rough estimates of the global sources of several OVOC and conclude that collectively these are extremely large (150-500 Tg C yr(-1)) but remain poorly quantified. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. Univ Rhode Isl, Grad Sch Oceanog, Ctr Atmospher Chem, Narragansett, RI 02882 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. Harvard Univ, Div Appl Sci, Cambridge, MA 02138 USA. RP NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM hanwant.b.singh@nasa.gov; lsalas@mail.arc.nasa.gov; chatfield@clio.arc.nasa.gov; eczech@mail.arc.nasa.gov; fried@acd.ucar.edu; walega@ucar.edu; mje@io.harvard.edu; bdf@sol.harvard.edu; djj@io.harvard.edu; drblake@uci.edu; zagar@notos.gso.uri.edu; robert.talbot@unh.edu; g.w.sachse@larc.nasa.gov; james.h.crawford@nasa.gov; m.a.avery@larc.nasa.gov; sts@minitower.gtri.gatech.edu; fuelberg@met.fsu.edu RI Evans, Mathew/A-3886-2012; Crawford, James/L-6632-2013 OI Evans, Mathew/0000-0003-4775-032X; Crawford, James/0000-0002-6982-0934 NR 83 TC 118 Z9 119 U1 8 U2 47 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 3 PY 2004 VL 109 IS D15 AR D15S07 DI 10.1029/2003JD003883 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 828DT UT WOS:000221954000002 ER PT J AU Tu, FH Thornton, DC Bandy, AR Carmichael, GR Tang, YH Thornhill, KL Sachse, GW Blake, DR AF Tu, FH Thornton, DC Bandy, AR Carmichael, GR Tang, YH Thornhill, KL Sachse, GW Blake, DR TI Long-range transport of sulfur dioxide in the central Pacific SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE sulfur dioxide; long-range transport; North Pacific ID TRACE-P EXPERIMENT; PEM-WEST-A; NORTH PACIFIC; HYDROCARBON RATIOS; MASS-SPECTROMETRY; AIR-POLLUTION; AEROSOL; ASIA; TROPOSPHERE; AMERICA AB Long-range transport of sulfur dioxide (SO2) from east Asia to the central North Pacific troposphere was observed on transit flights during the NASA Transport and Chemical Evolution over the Pacific mission. A series of SO2-enhanced layers above the boundary layer was observed during these flights. The significant features included enhanced SO2 layers associated with low water vapor and low turbulence that were usually dynamically isolated from the marine boundary layer. This study shows that atmospheric dynamics were very important in determining the SO2 distributions in the central Pacific during March and April 2001. Trajectory studies revealed that SO2-enhanced layers could be connected to both volcanic and anthropogenic sources in east Asia. These trajectory studies also showed that the air parcels usually were lifted 2 km above the source regions and then progressed to the east in the midlatitudes (30degrees-60degreesN). The air parcels arrived in the central Pacific within 2-3 days. Sulfur dioxide transported at altitudes of 2-4 km dominated the SO2 distribution in the central Pacific. A comparison of SO2 observations and results of chemical transport models indicated that SO2 was removed primarily by cloud processes. Therefore, in the absence of cloud, SO2 can be transported long distances if the trajectory is decoupled from the boundary layer. Another important observation was that the Miyake-jima volcano made a major contribution to the SO2 concentrations in the central Pacific troposphere during March and April 2001. At times, the volcanic SO2 had more influence in the central Pacific than the six largest anthropogenic SO2 source regions in east Asia. C1 Drexel Univ, Dept Chem, Philadelphia, PA 19104 USA. Univ Iowa, Ctr Global & Reg Environm Res, Iowa City, IA 52242 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. RP Drexel Univ, Dept Chem, 3141 Chestnut St, Philadelphia, PA 19104 USA. EM dct@drexel.edu RI Tang, Youhua/D-5205-2016 OI Tang, Youhua/0000-0001-7089-7915 NR 42 TC 26 Z9 26 U1 2 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 3 PY 2004 VL 109 IS D15 AR D15S08 DI 10.1029/2003JD004309 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 828DT UT WOS:000221954000004 ER PT J AU Nizkorodov, SA Sander, SP Brown, LR AF Nizkorodov, SA Sander, SP Brown, LR TI Temperature and pressure dependence of high-resolution air-broadened absorption cross sections of NO2 (415-525 nm) SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID FOURIER-TRANSFORM SPECTROSCOPY; LONG RADIATIVE LIFETIMES; EQUILIBRIUM-CONSTANT; ELECTRONIC-STRUCTURE; NITROGEN-DIOXIDE; VISIBLE REGION; 220 K; SPECTRUM; ULTRAVIOLET; N2O4 AB Cross sections of air-broadened NO2 in the 415-525 nm region are reported. These are retrieved from 21 absorption spectra recorded at 0.060 cm(-1) resolution with the McMath-Pierce Fourier Transform Spectrometer located on Kitt Peak in Arizona. The measurements are obtained for pressures (1-760 Torr) and temperatures (220-298 K) that are representative of typical tropospheric and stratospheric conditions. Two sigma uncertainty (95% confidence interval approximate to2sigma(mean)) for the absolute absorption cross sections is below +/-7% over the reported wavelength range. The average integrated intensity of all our data is (400-500nm) = 4.53 x 10(-17) cm(2) nm, which is within 0.2% of the averaged value from the recent literature. The wavelength (referred to vacuum) accuracy is 0.011 cm(-1) (2.8 x 10(-4) nm at 500 nm) and precision is 0.0022 cm(-1) throughout the investigated wavelength range. In agreement with previous observations, high-resolution features in the NO2 absorption spectrum display a strong pressure dependence with an effective pressure broadening parameter of 0.116 +/- 0.003 cm(-1)/atm (the rate of increase of Lorentzian half width at half-maximum with pressure). Temperature has a relatively minor effect on the shapes of individual high-resolution features, but it exerts a complex dependence on the relative line intensities. Absorption cross sections reported here represent the highest resolution data available over a substantial (> 100 nm) wavelength range for quantitative analysis of NO2 atmospheric column absorption spectra. C1 CALTECH, Arthur Amos Noyes Lab Chem Phys, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nizkorodov, SA (reprint author), Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. EM nizkorod@uci.edu; Stanley.P.Sander@jpl.nasa.gov; linda.brown@jpl.nasa.gov RI Nizkorodov, Sergey/I-4120-2014 OI Nizkorodov, Sergey/0000-0003-0891-0052 NR 36 TC 11 Z9 11 U1 1 U2 15 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 3 PY 2004 VL 108 IS 22 BP 4864 EP 4872 DI 10.1021/jp049461n PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 824QC UT WOS:000221700100007 ER PT J AU Jost, HJ Drdla, K Stohl, A Pfister, L Loewenstein, M Lopez, JP Hudson, PK Murphy, DM Cziczo, DJ Fromm, M Bui, TP Dean-Day, J Gerbig, C Mahoney, MJ Richard, EC Spichtinger, N Pittman, JV Weinstock, EM Wilson, JC Xueref, I AF Jost, HJ Drdla, K Stohl, A Pfister, L Loewenstein, M Lopez, JP Hudson, PK Murphy, DM Cziczo, DJ Fromm, M Bui, TP Dean-Day, J Gerbig, C Mahoney, MJ Richard, EC Spichtinger, N Pittman, JV Weinstock, EM Wilson, JC Xueref, I TI In-situ observations of mid-latitude forest fire plumes deep in the stratosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PARTICLE ANALYSIS; INSTRUMENT; TRANSPORT; TROPOPAUSE; MODEL; SMOKE AB [ 1] We observed a plume of air highly enriched in carbon monoxide and particles in the stratosphere at altitudes up to 15.8 km. It can be unambiguously attributed to North American forest fires. This plume demonstrates an extratropical direct transport path from the planetary boundary layer several kilometers deep into the stratosphere, which is not fully captured by large-scale atmospheric transport models. This process indicates that the stratospheric ozone layer could be sensitive to changes in forest burning associated with climatic warming. C1 Bay Area Environm Res Inst, Sonoma, CA 95476 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Tech Univ Munich, D-85354 Freising Weihenstephan, Germany. NOAA, Off Ocean & Atmospher Res, Boulder, CO 80305 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Computat Phys Inc, Springfield, VA 22151 USA. San Jose State Univ, San Jose, CA 95192 USA. Harvard Univ, Cambridge, MA 02138 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Denver, Dept Engn, Denver, CO 80208 USA. RP Jost, HJ (reprint author), Bay Area Environm Res Inst, 560 3rd St W, Sonoma, CA 95476 USA. EM hjost@mail.arc.nasa.gov RI Stohl, Andreas/A-7535-2008; Fromm, Michael/F-4639-2010; Murphy, Daniel/J-4357-2012; Gerbig, Christoph/L-3532-2013 OI Stohl, Andreas/0000-0002-2524-5755; Murphy, Daniel/0000-0002-8091-7235; Gerbig, Christoph/0000-0002-1112-8603 NR 21 TC 90 Z9 91 U1 2 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 2 PY 2004 VL 31 IS 11 AR L11101 DI 10.1029/2003GL019253 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 828DC UT WOS:000221952200002 ER PT J AU Tan, WW Geller, MA Pawson, S da Silva, A AF Tan, WW Geller, MA Pawson, S da Silva, A TI A case study of excessive subtropical transport in the stratosphere of a data assimilation system SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE subtropical transport barrier; data assimilation; stratosphere ID GENERAL-CIRCULATION MODEL; LAGRANGIAN-MEAN DIAGNOSTICS; SHALLOW-WATER MODEL; EFFECTIVE DIFFUSIVITY; TROPICAL STRATOSPHERE; ISENTROPIC TRANSPORT; WINTER STRATOSPHERE; PLANETARY-WAVES; POLAR VORTICES; TROPOSPHERE AB [ 1] Assessments of transport show that results derived from assimilated ( or analyzed) winds exhibit significantly larger mixing and entrainment rates compared to those derived from general circulation model (GCM) winds, where the GCM transport is somewhat closer ( statistically) to values inferred from observations. This discrepancy presents a challenge to our ability to understand and model the global distributions of long-lived trace gases. We use the Goddard Earth Observation System's Finite Volume Data Assimilation System to explore this issue by examining how the data assimilation process alters the dynamics of the underlying GCM and how this leads to greater lower stratospheric mixing and transport in the subtropics. We show that the excessive subtropical transport is related to the proliferation of eddy features in the subtropics, and we examine various possibilities that may cause this. These include the generation of upward propagating features, equatorward propagating features, and meridionally confined features in the process of data assimilation. In particular, it is argued that unstable regions forced directly by the analysis increments play an important role in generating the excess subtropical transport. C1 Sci Applicat Int Corp, Beltsville, MD USA. NASA, Global Modeling & Assimilat Off, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Stony Brook, NY 11794 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RP Tan, WW (reprint author), Sci Applicat Int Corp, Beltsville, MD USA. EM wtan@gmao.gsfc.nasa.gov; marvin.geller@sunysb.edu; spawson@gmao.gsfc.nasa.gov; asilva@gmao.gsfc.nasa.gov RI da Silva, Arlindo/D-6301-2012; Pawson, Steven/I-1865-2014 OI da Silva, Arlindo/0000-0002-3381-4030; Pawson, Steven/0000-0003-0200-717X NR 45 TC 34 Z9 34 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 2 PY 2004 VL 109 IS D11 AR D11102 DI 10.1029/2003JD004057 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 828DM UT WOS:000221953300001 ER PT J AU Venet, A Brat, G AF Venet, A Brat, G TI Precise and efficient static array bound checking for large embedded C programs SO ACM SIGPLAN NOTICES LA English DT Article; Proceedings Paper CT Conference on Programming Language Design and Implementation CY JUN 09-11, 2004 CL Washington, DC SP AMC SIGPLAN DE abstract interpretation; program verification; pointer analysis; array-bound checking; difference-bound matrices AB In this paper we describe the design and implementation of a static array-bound checker for a family of embedded programs: the flight control software of recent Mars missions. These codes are large (up to 280 KLOC), pointer intensive, heavily multithreaded and written in an object-oriented style, which makes their analysis very challenging. We designed a tool called C Global Surveyor (CGS) that can analyze the largest code in a couple of hours with a precision of 80%. The scalability and precision of the analyzer are achieved by using an incremental framework in which a pointer analysis and a numerical analysis of array indices mutually refine each other. CGS has been designed so that it can distribute the analysis over several processors in a cluster of machines. To the best of our knowledge this is the first distributed implementation of static analysis algorithms. Throughout the paper we will discuss the scalability setbacks that we encountered during the construction of the tool and their impact on the initial design decisions. C1 NASA, Ames Res Ctr, Kestrel Technol, Moffett Field, CA 94035 USA. RP Venet, A (reprint author), NASA, Ames Res Ctr, Kestrel Technol, Moffett Field, CA 94035 USA. EM arnaud@email.arc.nasa.gov; brat@email.arc.nasa.gov NR 25 TC 7 Z9 8 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 USA SN 0362-1340 J9 ACM SIGPLAN NOTICES JI ACM Sigplan Not. PD JUN PY 2004 VL 39 IS 6 BP 231 EP 242 DI 10.1145/996893.996869 PG 12 WC Computer Science, Software Engineering SC Computer Science GA 843XP UT WOS:000223120900021 ER PT J AU Culbertson, F AF Culbertson, F TI A tour of the ISS SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT World Space Congress 2002 CY OCT 10-19, 2002 CL HOUSTON, TEXAS C1 NASA, Washington, DC 20546 USA. RP Culbertson, F (reprint author), NASA, Washington, DC 20546 USA. NR 0 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 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JUN PY 2004 VL 54 IS 11-12 BP 793 EP 797 DI 10.1016/j.actasstro.2004.01.019 PG 5 WC Engineering, Aerospace SC Engineering GA 810MR UT WOS:000220708900009 PM 15793930 ER PT J AU Lucid, S AF Lucid, S TI How to use-the ISS SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT World Space Congress 2002 CY OCT 10-19, 2002 CL HOUSTON, TEXAS C1 NASA, Washington, DC 20546 USA. RP Lucid, S (reprint author), NASA, Washington, DC 20546 USA. NR 0 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 JUN PY 2004 VL 54 IS 11-12 BP 799 EP 800 DI 10.1016/j.actaastro.2004.01.020 PG 2 WC Engineering, Aerospace SC Engineering GA 810MR UT WOS:000220708900010 PM 15793932 ER PT J AU Gerstenmaier, W AF Gerstenmaier, W TI ISS plenary summary SO ACTA ASTRONAUTICA LA English DT Editorial Material C1 NASA, Washington, DC 20546 USA. RP Gerstenmaier, W (reprint author), NASA, Washington, DC 20546 USA. NR 0 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 JUN PY 2004 VL 54 IS 11-12 BP 801 EP 801 DI 10.1016/j.actaastro.2004.01.021 PG 1 WC Engineering, Aerospace SC Engineering GA 810MR UT WOS:000220708900011 ER PT J AU Lucid , S Kasturirangan Kline, D Singh Ravindran Barbosa, M Williams, E Arenales, O AF Lucid , S Kasturirangan Kline, D Singh Ravindran Barbosa, M Williams, E Arenales, O TI The use of space activities for achieving sustainable development - Discussion SO ACTA ASTRONAUTICA LA English DT Editorial Material C1 NASA HQ, Washington, DC USA. NR 0 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 JUN PY 2004 VL 54 IS 11-12 BP 877 EP 880 DI 10.1016/j.actaastro.2004.01.048 PG 4 WC Engineering, Aerospace SC Engineering GA 810MR UT WOS:000220708900026 ER PT J AU Saleeb, AF Marks, JR Wilt, TE Arnold, SM AF Saleeb, AF Marks, JR Wilt, TE Arnold, SM TI Interactive software for material parameter characterization of advanced engineering constitutive models SO ADVANCES IN ENGINEERING SOFTWARE LA English DT Article DE C plus; graphical user interface; optimization; material characterization; viscoplasticity ID STATE AB The development of an overall strategy to estimate the material parameters for a class of viscoplastic material models is presented. The procedure is automated through the integrated software COMPARE (Constitutive Material PARameter Estimator) that enables the determination of an 'optimum' set of material parameters by minimizing the errors between the experimental test data and the model's predicted response. The core ingredients of COMPARE are (i) primal analysis, which utilizes a finite element-based solution scheme, (ii) sensitivity analysis utilizing a direct-differentiation approach for the material response sensitivities, and (iii) a gradient-based optimization technique of an error/cost function. Now that the COMPARE core code has reached a level of maturity, a graphical user interface (GUI) was deemed necessary. Without such an interface, use of COMPARE was previously restricted to very experienced users with the additional cumbersome, and sometimes tedious, task of preparing the required input files manually. The complexity of the input containing massive amounts of data has previously placed severe limitations on the use of such optimization procedures by the general engineering community. By using C+ + and the Microsoft Foundation Classes to develop a GUI, it is believed that an advanced code such as COMPARE can now make the transition to general usability in an engineering environment. (C) 2004 Elsevier Ltd. All rights reserved. C1 Univ Akron, Dept Civil Engn, Akron, OH 44325 USA. NASA, Glenn Res Ctr, Life Predict Branch, Cleveland, OH 44135 USA. RP Univ Akron, Dept Civil Engn, Akron, OH 44325 USA. EM saleeb@uakron.edu NR 17 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0965-9978 EI 1873-5339 J9 ADV ENG SOFTW JI Adv. Eng. Softw. PD JUN PY 2004 VL 35 IS 6 BP 383 EP 398 DI 10.1016/j.advengsoft.2004.03.010 PG 16 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering; Engineering, Multidisciplinary SC Computer Science; Engineering GA 838NI UT WOS:000222719700006 ER PT J AU van der Wall, BG Burley, CL Yu, Y Richard, H Pengel, K Beaumier, P AF van der Wall, BG Burley, CL Yu, Y Richard, H Pengel, K Beaumier, P TI The HART II test - measurement of helicopter rotor wakes SO AEROSPACE SCIENCE AND TECHNOLOGY LA English DT Article DE rotor wake; active blade control AB A key parameter to reduce rotor noise is a wake location relative to a blade. During the data analysis in the years after the HART test of 1994 it was found that comprehensive wake data are needed to understand wake development, vortex creation and aging, their motion and their re-development after an interaction with a rotor blade. Therefore, DLR, ONERA, NASA Langley, US Army AFDD and DNW again came together and generated a follow-on program named HART II. In this program the rotor wake was intensively measured with a novel double-stereo PIV (Particle Image Velocimetry) system. This provides instantaneous flow field data in both a large observation area and in a smaller close-up view to the vortex core. Additionally, rotor blade deformation, airloads, and noise radiation were measured to form a complete, consistent, and comprehensive data base. Another "first time" was the application of the blade position measurement technique SPR (Stereo Pattern Recognition), which provided instantaneous optical measurement of the blade bending in flap, lead-lag and torsion. In this paper, the HART II test is described in detail, including a description of all measurement techniques applied and with some results from each of them. (C) 2004 Elsevier SAS. All rights reserved. C1 DLR, Inst Flugsyst Tech, D-38108 Braunschweig, Germany. NASA, Langley Res Ctr, Hampton, VA 23681 USA. USA, AFDD, NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. DLR, Inst Aerodynam & Stromungstech, D-37073 Gottingen, Germany. Deutsch Niderland Windkanal, NL-8300 AD Emmeloord, Netherlands. Off Natl Etud & Rech Aerosp, F-92322 Chatillon, France. RP van der Wall, BG (reprint author), DLR, Inst Flugsyst Tech, Lilienthalpl 7, D-38108 Braunschweig, Germany. EM berend.vanderwall@dlr.de NR 18 TC 19 Z9 19 U1 0 U2 1 PU EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS PA 23 RUE LINOIS, 75724 PARIS, FRANCE SN 1270-9638 J9 AEROSP SCI TECHNOL JI Aerosp. Sci. Technol. PD JUN PY 2004 VL 8 IS 4 BP 273 EP 284 DI 10.1016/j.ast.2004.01.001 PG 12 WC Engineering, Aerospace SC Engineering GA 834RH UT WOS:000222427800002 ER PT J AU Nemec, M Zingg, DW Pulliam, TH AF Nemec, M Zingg, DW Pulliam, TH TI Multipoint and multi-objective aerodynamic shape optimization SO AIAA JOURNAL LA English DT Article ID NAVIER-STOKES EQUATIONS; 2-EQUATION TURBULENCE MODELS; HIGH-LIFT; DESIGN OPTIMIZATION; ADJOINT FORMULATION; UNSTRUCTURED MESHES; PARALLEL COMPUTERS; AIRFOIL DESIGN; COMPUTATIONS; CONFIGURATIONS AB A gradient-based Newton-Krylov algorithm is presented for the aerodynamic shape optimization of single- and multi-element airfoil configurations. The flow is governed by the compressible Navier-Stokes equations in conjunction with a one-equation transport turbulence model. The preconditioned generalized minimal residual method is applied to solve the discrete-adjoint equation, which leads to a fast computation of accurate objective function gradients. Optimization constraints are enforced through a penalty formulation, and the resulting unconstrained problem is solved via a quasi-Newton method. The new algorithm is evaluated for several design examples, including the lift enhancement of a takeoff configuration and a lift-constrained drag minimization at multiple transonic operating points. Furthermore, the new algorithm is used to compute a Pareto front based on competing objectives, and the results are validated using a genetic algorithm. Overall, the new algorithm provides an efficient approach for addressing the issues of complex aerodynamic design. C1 NASA, Ames Res Ctr, Adv Supercomp Div, Moffett Field, CA 94035 USA. Univ Toronto, Toronto, ON M3H 5T6, Canada. RP Nemec, M (reprint author), NASA, Ames Res Ctr, Adv Supercomp Div, Moffett Field, CA 94035 USA. EM nemec@nas.nasa.gov; dwz@oddjob.utias.utoronto.ca; tpulliam@mail.arc.nasa.gov NR 47 TC 64 Z9 65 U1 0 U2 11 PU AMER INST AERONAUTICS ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 EI 1533-385X J9 AIAA J JI AIAA J. PD JUN PY 2004 VL 42 IS 6 BP 1057 EP 1065 DI 10.2514/1.10415 PG 9 WC Engineering, Aerospace SC Engineering GA 827LW UT WOS:000221902300001 ER PT J AU Massey, R Rhodes, J Refregier, A Albert, J Bacon, D Bernstein, G Ellis, R Jain, B McKay, T Perlmutter, S Taylor, A AF Massey, R Rhodes, J Refregier, A Albert, J Bacon, D Bernstein, G Ellis, R Jain, B McKay, T Perlmutter, S Taylor, A TI Weak lensing from space. II. Dark matter mapping SO ASTRONOMICAL JOURNAL LA English DT Article DE dark matter; gravitational lensing; large-scale structure of universe; space vehicles : general ID LARGE-SCALE STRUCTURE; POWER-SPECTRUM NORMALIZATION; RAY-LUMINOUS CLUSTERS; COSMIC SHEAR; SURVEY FIELDS; GALAXIES; TELESCOPE; STATISTICS; SNAP; SHAPELETS AB We study the accuracy with which weak-lensing measurements could be made from a future space-based survey, predicting the subsequent precision of three-dimensional dark matter maps, projected two-dimensional dark matter maps, and mass-selected cluster catalogs. As a baseline, we use the instrumental specifications of the SuperNova/Acceleration Probe ( SNAP) satellite. We first compute its sensitivity to weak lensing shear as a function of survey depth. Our predictions are based on detailed image simulations created using "shapelets,'' a complete and orthogonal parameterization of galaxy morphologies. We incorporate a realistic redshift distribution of source galaxies and calculate the average precision of photometric redshift recovery using the SNAP filter set to be Deltaz = 0.034. The high density of background galaxies resolved in a wide space-based survey allows projected dark matter maps with an rms sensitivity of 3% shear in 1 arcmin(2) cells. This will be further improved using a proposed deep space-based survey, which will be able to detect isolated clusters using a three-dimensional lensing inversion technique with a 1 sigma mass sensitivity of approximately 10(13) M. at z = 0.25. Weak-lensing measurements from space will thus be able to capture non-Gaussian features arising from gravitational instability and map out dark matter in the universe with unprecedented resolution. C1 Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. CALTECH, Dept Astron, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NASA, NRC, Washington, DC 20546 USA. Univ Edinburgh, Inst Astron, Edinburgh EH9 3HJ, Midlothian, Scotland. Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Massey, R (reprint author), Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England. EM rjm@ast.cam.ac.uk RI McKay, Timothy/C-1501-2009; Perlmutter, Saul/I-3505-2015 OI McKay, Timothy/0000-0001-9036-6150; Perlmutter, Saul/0000-0002-4436-4661 NR 82 TC 42 Z9 42 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 2004 VL 127 IS 6 BP 3089 EP 3101 DI 10.1086/420985 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 828VU UT WOS:000222002600002 ER PT J AU Refregier, A Massey, R Rhodes, J Ellis, R Albert, J Bacon, D Bernstein, G McKay, T Perlmutter, S AF Refregier, A Massey, R Rhodes, J Ellis, R Albert, J Bacon, D Bernstein, G McKay, T Perlmutter, S TI Weak lensing from space. III. Cosmological parameters SO ASTRONOMICAL JOURNAL LA English DT Article DE cosmological parameters; gravitational lensing; large-scale structure of universe ID LARGE-SCALE STRUCTURE; POWER SPECTRUM; DARK ENERGY; STATISTICS; OMEGA; PROBE AB Weak gravitational lensing provides a unique method to directly map the dark matter in the universe and measure cosmological parameters. Current weak-lensing surveys are limited by the atmospheric seeing from the ground and by the small fields of view of existing space telescopes. We study how a future wide-field space telescope can measure the lensing power spectrum and skewness and thus set constraints on cosmological parameters. The lensing sensitivity was calculated using detailed image simulations and instrumental specifications studied in earlier papers in this series. For instance, the planned SuperNova/Acceleration Probe ( SNAP) mission will be able to measure the matter density parameter Omega(m) and the dark energy equation-of-state parameter w with precisions comparable and nearly orthogonal to those derived with SNAP from supernovae. The constraints degrade by a factor of about 2 if redshift tomography is not used but are little affected if only the skewness is dropped. We also study how the constraints on these parameters depend on the survey geometry and define an optimal observing strategy. C1 CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. CALTECH, Dept Astron, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NASA, NRC, Washington, DC 20546 USA. Univ Edinburgh, Inst Astron, Edinburgh EH9 3HJ, Midlothian, Scotland. Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Refregier, A (reprint author), CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. EM refregier@cea.fr RI McKay, Timothy/C-1501-2009; Perlmutter, Saul/I-3505-2015 OI McKay, Timothy/0000-0001-9036-6150; Perlmutter, Saul/0000-0002-4436-4661 NR 34 TC 67 Z9 67 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 2004 VL 127 IS 6 BP 3102 EP 3114 DI 10.1086/420986 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 828VU UT WOS:000222002600003 ER PT J AU Surace, JA Sanders, DB Mazzarella, JM AF Surace, JA Sanders, DB Mazzarella, JM TI An IRAS high resolution image restoration (HIRES) atlas of all interacting galaxies in the IRAS Revised Bright Galaxy Sample SO ASTRONOMICAL JOURNAL LA English DT Article DE atlases; galaxies : interactions; infrared : galaxies; infrared : general; techniques : image processing ID INFRARED-EMISSION; STAR-FORMATION; SEYFERT-GALAXIES; PAIRED GALAXIES; BINARY GALAXIES; STARBURSTS; SYSTEMS; MERGERS; ISOCAM AB The importance of far-infrared observations for our understanding of extreme activity in interacting and merging galaxies has been illustrated by many studies. Even though two decades have passed since its launch, the most complete all-sky survey to date from which far-IR selected galaxy samples can be chosen is still that of the Infrared Astronomical Satellite (IRAS). However, the spatial resolution of the IRAS all-sky survey is insufficient to resolve the emission from individual galaxies in most interacting galaxy pairs, and hence previous studies of their far-IR properties have had to concentrate either on global system properties or on the properties of very widely separated and weakly interacting pairs. Using the HIRES image reconstruction technique, it is possible to achieve a spatial resolution ranging from 30" to 1.'5 (depending on wavelength and detector coverage), which is a fourfold improvement over the normal resolution of IRAS. This is sufficient to resolve the far-IR emission from the individual galaxies in many interacting systems detected by IRAS, which is very important for meaningful comparisons with single, isolated galaxies. We present high-resolution 12, 25, 60, and 100 mum images of 106 interacting galaxy systems contained in the IRAS Revised Bright Galaxy Sample (RBGS, Sanders et al.), a complete sample of all galaxies having a 60 mum flux density greater than 5.24 Jy. These systems were selected to have at least two distinguishable galaxies separated by less than three average galactic diameters, and thus we have excluded very widely separated systems and very advanced mergers. Additionally, some systems have been included that are more than three galactic diameters apart, yet have separations less than 40 and are thus likely to suffer from confusion in the RBGS. The new complete survey has the same properties as the prototype survey of Surace et al. We find no increased tendency for infrared-bright galaxies to be associated with other infrared-bright galaxies among the widely separated pairs studied here. We find small enhancements in far-IR activity in multiple galaxy systems relative to RBGS noninteracting galaxies with the same blue luminosity distribution. We also find no differences in infrared activity ( as measured by infrared color and luminosity) between late- and early-type spiral galaxies. C1 CALTECH, Jet Prop Lab, Spitzer Sci Ctr, Pasadena, CA 91125 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. CALTECH, Jet Prop Lab, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. RP Surace, JA (reprint author), CALTECH, Jet Prop Lab, Spitzer Sci Ctr, MS 220-6, Pasadena, CA 91125 USA. OI Mazzarella, Joseph/0000-0002-8204-8619 NR 28 TC 53 Z9 53 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 JUN PY 2004 VL 127 IS 6 BP 3235 EP 3272 DI 10.1086/420705 PG 38 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 828VU UT WOS:000222002600014 ER PT J AU Golimowski, DA Leggett, SK Marley, MS Fan, X Geballe, TR Knapp, GR Vrba, FJ Henden, AA Luginbuhl, CB Guetter, HH Munn, JA Canzian, B Zheng, W Tsvetanov, ZI Chiu, K Glazebrook, K Hoversten, EA Schneider, DP Brinkmann, J AF Golimowski, DA Leggett, SK Marley, MS Fan, X Geballe, TR Knapp, GR Vrba, FJ Henden, AA Luginbuhl, CB Guetter, HH Munn, JA Canzian, B Zheng, W Tsvetanov, ZI Chiu, K Glazebrook, K Hoversten, EA Schneider, DP Brinkmann, J TI L ' and M ' photometry of ultracool dwarfs SO ASTRONOMICAL JOURNAL LA English DT Article DE infrared : stars; stars : fundamental parameters; stars : late-type; stars : low-mass, brown dwarfs ID LOW-MASS STARS; EXTRASOLAR GIANT PLANETS; INFRARED FILTER SET; DIGITAL SKY SURVEY; COOL BROWN DWARF; T-DWARFS; GLIESE 229B; SPECTRAL CLASSIFICATION; OPTICAL SPECTROSCOPY; EVOLUTIONARY MODELS AB We have compiled L' (3.4 - 4.1 mum) and M' (4.6 - 4.8 mum) photometry of 63 single and binary M, L, and T dwarfs obtained at the United Kingdom Infrared Telescope using the Mauna Kea Observatory filter set. This compilation includes new L' measurements of eight L dwarfs and 13 T dwarfs and new M' measurements of seven L dwarfs, five T dwarfs, and the M1 dwarf Gl 229A. These new data increase by factors of 0.6 and 1.6, respectively, the numbers of ultracool dwarfs (T-eff less than or similar to2400 K) for which L' and M' measurements have been reported. We compute L-bol, BCK, and T-eff for 42 dwarfs whose flux-calibrated JHK spectra, L' photometry, and trigonometric parallaxes are available, and we estimate these quantities for nine other dwarfs whose parallaxes and flux-calibrated spectra have been obtained. BCK is a well-behaved function of near-infrared spectral type with a dispersion of similar to 0.1 mag for types M6 - T5; it is significantly more scattered for types T5 - T9. T-eff declines steeply and monotonically for types M6 - L7 and T4 - T9, but it is nearly constant at similar to 1450 K for types L7 - T4 with assumed ages of similar to 3 Gyr. This constant T-eff is evidenced by nearly unchanging values of L'-M' between types L6 and T3. It also supports recent models that attribute the changing near-infrared luminosities and spectral features across the L-T transition to the rapid migration, disruption, and/or thinning of condensate clouds over a narrow range of T-eff. The L' and M' luminosities of early-T dwarfs do not exhibit the pronounced humps or inflections previously noted in the I through K bands, but insufficient data exist for types L6 - T5 to assert that M-L' and M-M' are strictly monotonic within this range of types. We compare the observed K, L', and M' luminosities of L and T dwarfs in our sample with those predicted by precipitating-cloud and cloud-free models for varying surface gravities and sedimentation efficiencies. The models indicate that the L3-T4.5 dwarfs generally have higher gravities ( log g = 5.0 - 5.5) than the T6 - T9 dwarfs ( log g = 4.5 - 5.0). The predicted M' luminosities of late-T dwarfs are 1.5 - 2.5 times larger than those derived empirically for the late-T dwarfs in our sample. This discrepancy is attributed to absorption at 4.5 - 4.9 mum by CO, which is not expected under the condition of thermochemical equilibrium assumed in the models. Our photometry and bolometric calculations indicate that the L3 dwarf Kelu-1 and the T0 dwarf SDSS J042348.57 - 041403.5 are probable binary systems. We compute log (L-bol/L-.) = - 5.73 +/- 0.05 and T-eff = 600 - 750 K for the T9 dwarf 2MASSI J0415195 - 093506, which supplants Gl 570D as the least luminous and coolest brown dwarf presently known. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Joint Astron Ctr, United Kingdom Infrared Telescope, Hilo, HI 96720 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Gemini Observ, Hilo, HI 96720 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. USN Observ, Flagstaff Stn, Flagstaff, AZ 86002 USA. NASA, Washington, DC 20546 USA. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Apache Point Observ, Sunspot, NM 88349 USA. RP Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. RI Marley, Mark/I-4704-2013; Glazebrook, Karl/N-3488-2015; OI Glazebrook, Karl/0000-0002-3254-9044; Leggett, Sandy/0000-0002-3681-2989 NR 88 TC 373 Z9 373 U1 0 U2 3 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 2004 VL 127 IS 6 BP 3516 EP 3536 DI 10.1086/420709 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 828VU UT WOS:000222002600035 ER PT J AU Knapp, GR Leggett, SK Fan, X Marley, MS Geballe, TR Golimowski, DA Finkbeiner, D Gunn, JE Hennawi, J Ivezic, Z Lupton, RH Schlegel, DJ Strauss, MA Tsvetanov, ZI Chiu, K Hoversten, EA Glazebrook, K Zheng, W Hendrickson, M Williams, CC Uomoto, A Vrba, FJ Henden, AA Luginbuhl, CB Guetter, HH Munn, JA Canzian, B Schneider, DP Brinkmann, J AF Knapp, GR Leggett, SK Fan, X Marley, MS Geballe, TR Golimowski, DA Finkbeiner, D Gunn, JE Hennawi, J Ivezic, Z Lupton, RH Schlegel, DJ Strauss, MA Tsvetanov, ZI Chiu, K Hoversten, EA Glazebrook, K Zheng, W Hendrickson, M Williams, CC Uomoto, A Vrba, FJ Henden, AA Luginbuhl, CB Guetter, HH Munn, JA Canzian, B Schneider, DP Brinkmann, J TI Near-infrared photometry and spectroscopy of L and T dwarfs: The effects of temperature, clouds, and gravity SO ASTRONOMICAL JOURNAL LA English DT Article DE infrared : stars; stars : fundamental parameters; stars : late-type; stars : low-mass, brown dwarfs ID DIGITAL SKY SURVEY; SURVEY COMMISSIONING DATA; EXTRASOLAR GIANT PLANETS; LOW-MASS STARS; BROWN DWARFS; SPECTRAL CLASSIFICATION; SUBSTELLAR OBJECTS; MODEL ATMOSPHERES; ULTRACOOL DWARFS; BINARY-SYSTEMS AB We present new JHK photometry on the MKO-NIR system and JHK spectroscopy for a large sample of L and T dwarfs. Photometry has been obtained for 71 dwarfs, and spectroscopy for 56. The sample comprises newly identified very red objects from the Sloan Digital Sky Survey (SDSS) and known dwarfs from the SDSS and the Two Micron All Sky Survey ( 2MASS). Spectral classification has been carried out using four previously defined indices from Geballe et al. that measure the strengths of the near infrared water and methane bands. We identify nine new L8 - 9.5 dwarfs and 14 new T dwarfs from SDSS, including the latest yet found by SDSS, the T7 dwarf SDSS J175805.46+463311.9. We classify 2MASS J04151954 - 0935066 as T9, the latest and coolest dwarf found to date. We combine the new results with our previously published data to produce a sample of 59 L dwarfs and 42 T dwarfs with imaging data on a single photometric system and with uniform spectroscopic classification. We compare the near-infrared colors and absolute magnitudes of brown dwarfs near the L - T transition with predictions made by models of the distribution and evolution of photospheric condensates. There is some scatter in the Geballe et al. spectral indices for L dwarfs, suggesting that these indices are probing different levels of the atmosphere and are affected by the location of the condensate cloud layer. The near-infrared colors of the L dwarfs also show scatter within a given spectral type, which is likely due to variations in the altitudes, spatial distributions, and thicknesses of the clouds. We have identified a small group of late-L dwarfs that are relatively blue for their spectral type and that have enhanced FeH, H2O, and K I absorption, possibly due to an unusually small amount of condensates. The scatter seen in the H - K color for late-T dwarfs can be reproduced by models with a range in surface gravity. The variation is probably due to the effect on the K-band flux of pressure-induced H-2 opacity. The correlation of H - K color with gravity is supported by the observed strengths of the J-band K I doublet. Gravity is closely related to mass for field T dwarfs with ages greater than 10(8) yr and the gravities implied by the H - K colors indicate that the T dwarfs in our sample have masses in the range 15 - 75M(Jupiter). One of the SDSS dwarfs, SDSS J111010.01+ 011613.1, is possibly a very low mass object, with log g similar to 4.2 - 4.5 and mass similar to 10 - 15M(Jupiter). C1 Princeton Univ Observ, Princeton, NJ 08544 USA. Joint Astron Ctr, United Kingdom Infrared Telescope, Hilo, HI 96720 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Gemini Observ, Hilo, HI 96720 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Carnegie Observ, Pasadena, CA 91101 USA. USN Observ, Flagstaff Stn, Flagstaff, AZ 86002 USA. Univ Space Res Assoc, Washington, DC 20036 USA. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Apache Point Observ, Sunspot, NM 88349 USA. RP Princeton Univ Observ, Peyton Hall, Princeton, NJ 08544 USA. RI Marley, Mark/I-4704-2013; Glazebrook, Karl/N-3488-2015; OI Glazebrook, Karl/0000-0002-3254-9044; Leggett, Sandy/0000-0002-3681-2989 NR 99 TC 356 Z9 357 U1 0 U2 7 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 2004 VL 127 IS 6 BP 3553 EP 3578 DI 10.1086/420707 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 828VU UT WOS:000222002600037 ER PT J AU Fey, AL Ma, C Arias, EF Charlot, P Feissel-Vernier, M Gontier, AM Jacobs, CS Li, J MacMillan, DS AF Fey, AL Ma, C Arias, EF Charlot, P Feissel-Vernier, M Gontier, AM Jacobs, CS Li, J MacMillan, DS TI The second extension of the International Celestial Reference Frame: ICRF-EXT.1 SO ASTRONOMICAL JOURNAL LA English DT Article DE astrometry; catalogs; quasars : general; radio continuum : galaxies; reference systems; techniques : interferometric ID RADIO REFERENCE FRAME; EXTRAGALACTIC REFERENCE SYSTEM; BASE-LINE INTERFEROMETRY; VLBA CALIBRATOR SURVEY; ASTROMETRIC SUITABILITY; DELAY AB We use very long baseline interferometry data obtained between mid-1995 and the end of 2002 May together with older data to extend and revise the International Celestial Reference Frame ( ICRF). Revised positions of ICRF candidate and "other'' sources, based on inclusion of the additional data, are presented. Positions, in the frame of the ICRF, for an additional 109 new sources are also presented. All but four of the new sources are located north of delta = -30degrees. Positions of the ICRF defining sources remain unchanged. We present a summary of current astrometric and geodetic observing programs and discuss the evolution and future of the ICRF. C1 USN Observ, Washington, DC 20392 USA. NASA, Space Geodesy Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Bur Int Poids & Mesures, F-92312 Sevres, France. Observ Aquitain Sci Univers, CNRS, UMR 5804, F-33270 Floirac, France. Observ Paris, UMR 8630, F-75014 Paris, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Shanghai Astron Observ, Shanghai 200030, Peoples R China. RP Fey, AL (reprint author), USN Observ, 3450 Massachusetts Ave NW, Washington, DC 20392 USA. RI Ma, Chopo/D-4751-2012 NR 38 TC 140 Z9 145 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 2004 VL 127 IS 6 BP 3587 EP 3608 DI 10.1086/420998 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 828VU UT WOS:000222002600039 ER PT J AU Imai, H Morris, M Sahai, R Hachisuka, K Azzollini, JR AF Imai, H Morris, M Sahai, R Hachisuka, K Azzollini, JR TI The kinematics of water masers in the stellar molecular outflow source, RAS 19134+2131 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE masers; stars : AGB and post-AGB; stars : distances; stars : kinematics; stars : winds, outflows; stars : individual : IRAS 19134+2131 ID STAR-FORMING REGIONS; H2O MASERS; NEBULA AB Using the Very Large At-ray (VLA) and the Very Long Baseline Array (VLBA), we have observed water maser emission in the proto-planetary nebula candidate IRAS 19134+2131, in which the water maser spectrum has two groups of 14 emission features separated in radial velocity by similar to100 km s(-1). The blue-shifted and red-shifted clusters of maser features are clearly separated spatially by similar to150 mas, indicative of a fast collimated flow. However, not all of the maser features are aligned along the axis of the flow, as is seen in the similar high-velocity water maser source, W43A. Comparing the VLA and VLBA maps of the water maser source, we find 4 maser features that were active for 2 years. Using only VLBA data, we identified proper motions for 8 maser features. The full 3D outflow velocity is estimated to be similar to130 km s(-1), indicating that the dynamical age of the flow is only similar to50 yr. On the basis of the relative positions with respect to the nearby extragalactic reference source, J1925+2106, we also obtain a secular motion of IRAS 19134+2131 of mu(l) = -4.6 +/- 0.7 mas yr(-1) along the Galactic plane toward the Galactic centre. This indicates a "far distance" (greater than or equal to16 kpc) for IRAS 19134+2131 if the Galactic rotation curve remains flat at 220 km s(-1). C1 Joint Inst VLBI Europe, NL-7990 AA Dwingeloo, Netherlands. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Valencia, Dept Astron, E-46100 Burjassot, Spain. Inst Astrofis Canarias, Tenerife 38200, Spain. RP Imai, H (reprint author), Joint Inst VLBI Europe, Postbus 2, NL-7990 AA Dwingeloo, Netherlands. EM imai@jive.nl; morris@astro.ucla.edu; Raghvendra.Sahai@jpl.nasa.gov; kazuya.hachisuka@uv.es; iraf@cca.iac.es NR 15 TC 21 Z9 21 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN PY 2004 VL 420 IS 1 BP 265 EP 271 DI 10.1051/0004-6361:20035664 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827WK UT WOS:000221934200026 ER PT J AU Haberl, F Pietsch, W Schartel, N Rodriguez, P Corbet, RHD AF Haberl, F Pietsch, W Schartel, N Rodriguez, P Corbet, RHD TI Two long-period X-ray pulsars detected in the SMC field around XTE J0055-727 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : individual : Small Magellanic Cloud; stars : neutron; X-rays : binaries; X-rays : galaxies ID SMALL-MAGELLANIC-CLOUD; XMM-NEWTON; BINARIES; CATALOG; STAR AB An XMM-Newton target of opportunity observation of the field around the transient 18.37 s pulsar XTEJ0055-727 in the Small Magellanic Cloud (SMC) revealed two bright, long-period X-ray pulsars in the EPIC data. A new pulsar, XMMUJ005517.9-723853, with a pulse period of 701.7 +/- 0.8 s was discovered and 500.0 +/- 0.2 s pulsations were detected from XMMUJ005455.4-724512 (=CXOUJ005455.6-724510), confirming the period found in Chandra data. We derive X-ray positions of RA = 00(h)54(m)55.(s)88, Dec = -72degrees45'10."5 and RA = 00(h)55(m)18.(s)44, Dec = -72degrees38'51."8 (J2000.0) with an uncertainty of 0."2 utilizing optical identification with OGLE stars. For both objects, the optical brightness and colours and the X-ray spectra are consistent with Be/X-ray binary systems in the SMC. C1 Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. XMM Newton Sci Operat Ctr, ESA, Madrid 28080, Spain. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. RP Haberl, F (reprint author), Max Planck Inst Extraterr Phys, Giessenbach Str, D-85748 Garching, Germany. EM fwh@mpe.mpg.de NR 14 TC 12 Z9 12 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN PY 2004 VL 420 IS 3 BP L19 EP L22 DI 10.1051/0004-6361:20040156 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 845MW UT WOS:000223249600001 ER PT J AU Kraemer, SB George, IM Crenshaw, DM Gabel, JR AF Kraemer, SB George, IM Crenshaw, DM Gabel, JR TI On the relationship between the optical emission-line and X-ray luminosities in Seyfert 1 galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : Seyfert; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; SPECTRAL ENERGY-DISTRIBUTION; HOLE-BULGE RELATION; PHYSICAL CONDITIONS; SPACE-TELESCOPE; INFRARED-SPECTROSCOPY; ULTRAVIOLET ABSORBERS; TON S180; NGC 4151; REGION AB We have explored the relationship between the [O III] lambda5007 and the 2-10 keV luminosities for a sample of broad- and narrow-line Seyfert 1 galaxies (BLSy1s and NLSy1s, respectively). We find that both types of Seyfert galaxies span the same range in luminosity and possess similar [O III]/X-ray ratios. The NLSy1s are more luminous than BLSy1s when normalized to their central black hole masses, a fact attributed to higher mass accretion rates. However, we find no evidence for elevated [O III]/X-ray ratios in NLSy1s, which would have been expected if they had excess extreme-ultraviolet (EUV) continuum emission compared to BLSy1s. Also, other studies suggest that the gas in narrow-line regions (NLRs) of NLSy1s and BLSy1s spans a similar range in ionization, contrary to what is expected if those of the former are exposed to a stronger flux of EUV radiation. The simplest interpretation is that, like BLSy1s, a large EUV bump is not present in NLSy1s. However, we show that the [O III]/X-ray ratio can be lowered as a result of absorption of the ionizing continuum by gas close to the central source, although there is no evidence that intrinsic line-of-sight absorption is more common among NLSy1s, as would be expected if there were a larger amount of circumnuclear gas. Other possible explanations include ( 1) anisotropic emission of the ionizing radiation; ( 2) higher gas densities in the NLRs of NLSy1s, resulting in lower average ionization; or ( 3) the presence of strong winds in the nuclei of NLSy1s that may drive off much of the gas in the NLR, resulting in lower cover fraction and weaker [O III] emission. C1 Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Dept Phys, Joint Ctr Astrophys, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. RP Kraemer, SB (reprint author), Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. EM kraemer@yancey.gsfc.nasa.gov; ian.george@gsfc.gsfc.nasa.gov; crenshaw@chara.gsu.edu; gabel@iacs.gsfc.nasa.gov NR 58 TC 14 Z9 14 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 2004 VL 607 IS 2 BP 794 EP 799 DI 10.1086/383529 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822LC UT WOS:000221540100013 ER PT J AU Dwek, E AF Dwek, E TI The detection of cold dust in Cassiopeia A: Evidence for the formation of metallic needles in the ejecta SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; infrared : ISM; ISM : individual (Cassiopeia A); supernova remnants ID GALACTIC SUPERNOVA-REMNANTS; INFRARED-EMISSION; II SUPERNOVAE; IRON WHISKERS; GRAINS; EVOLUTION; NUCLEOSYNTHESIS; SN-1987A; CHANDRA; ENERGY AB Ejecta from core-collapse supernovae contain a few solar masses of refractory elements and therefore can be the most important source of interstellar dust if these elements condense efficiently into solids. However, infrared observations of young supernova remnants, such as Cas A or Kepler, and observations of SN 1987A have detected only similar to10(-3) M. of hot dust in these objects. Recently, Dunne et al. obtained 450 and 850 mum SCUBA images of Cas A and reported the detection of 2-4 M. of cold ( 18 K) dust in the remnant. Here we show that their interpretation of the observations faces serious difficulties. Their inferred dust mass ignores the effect of grain destruction by sputtering and is larger than the mass of refractory material in the ejecta of a 10-30 M. star. The cold dust model faces even more difficulties if the 170 mum observations of the remnant are included in the analysis, which decreases the cold dust temperature to similar to8 K and increases its mass to greater than or similar to20 M.. We offer here a more plausible interpretation of their observation, in which the cold dust emission is generated by conducting needles in the ejecta. The needle properties are completely determined by the combined submillimeter and X-ray observations of the remnant. The needles are collisionally heated by the shocked gas. They are very efficient emitters at submillimeter wavelengths and, with a resistivity of a few muOmega cm, can readily attain a temperature of 8 K. Taking the destruction of needles into account, a dust mass of only 10(-4) to 10(-3) M. is needed to account for the observed SCUBA emission. The needles consist of metallic whiskers with less than or similar to1% of embedded impurities, which may have condensed out of blobs of material that were expelled at high velocities from the inner metal-rich layers of the star in an asymmetric explosion. Conductive needles may also be the source of the cold dust emission detected by Morgan et al. in Kepler. When aligned in the magnetic field, needles may give rise to observable polarized emission. The detection of submillimeter polarization will therefore offer definitive proof for a needle origin for the cold dust emission. Supernovae may yet be proven to be important sources of interstellar dust, but the evidence is still inconclusive. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Dwek, E (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 41 TC 53 Z9 53 U1 0 U2 1 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 2004 VL 607 IS 2 BP 848 EP 854 DI 10.1086/382653 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822LC UT WOS:000221540100019 ER PT J AU Rho, J Ramirez, SV Corcoran, MF Hamaguchi, K Lefloch, B AF Rho, J Ramirez, SV Corcoran, MF Hamaguchi, K Lefloch, B TI Chandra observation of the trifid nebula: X-ray emission from the O star complex and actively forming pre-main-sequence stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : individual (Trifid Nebula); stars : activity; stars : pre-main-sequence; X-rays : stars ID ALL-SKY SURVEY; ORION NEBULA; IMAGING SPECTROMETER; HOT STARS; WINDS; CATALOG; ENERGY AB The Trifid Nebula, a young star-forming H II region, was observed for 16 hr by the ACIS-I detector on board the Chandra X-Ray Observatory. We detected 304 X-ray sources, 30% of which are hard sources and 70% of which have near-infrared counterparts. Chandra resolved the HD 164492 multiple system into a number of discrete X-ray sources. X-ray emission is detected from components HD 164492A (an O7.5 III star that ionizes the nebula), B and C (a B6 V star), and possibly D (a Be star). Component C is blended with an unidentified source to the northwest. HD 164492A has a soft spectrum (kT approximate to 0.5 keV), while the component C blend shows much harder emission (kT approximate to 6 keV). This blend and other hard sources are responsible for the hard emission and Fe K line seen by ASCA, which was previously attributed entirely to HD 164492A. The soft spectrum of the O star is similar to emission seen from other single O stars and is probably produced by shocks within its massive stellar wind. Lack of hard emission suggests that neither a magnetically confined wind shock nor colliding wind emission is important in HD 164492A. A dozen stars are found to have flares in the field, and most of them are pre-main-sequence stars (PMS). Six sources with flares have both optical and Two Micron All Sky Survey counterparts. These counterparts are not embedded, and thus it is likely that these sources are in a later stage of PMS evolution, possibly Class II or III. Two flare sources did not have any near-IR, optical, or radio counterparts. We suggest that these X-ray flare stars are in an early PMS stage (Class I or earlier). We also detected X-ray sources apparently associated with two massive star-forming cores, TC 1 and TC 4. The spectra of these sources show high extinction and X-ray luminosities of (2-5) x 10(31) ergs s(-1). If these sources are Class 0 objects, it is unclear whether their X-ray emission is due to solar-type magnetic activities, as in Class I objects, or to some other mechanism. C1 CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Observ Grenoble, Astrophys Lab, F-38041 Grenoble, France. RP Rho, J (reprint author), CALTECH, Spitzer Sci Ctr, MS 220-06, Pasadena, CA 91125 USA. NR 38 TC 22 Z9 22 U1 0 U2 1 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 2004 VL 607 IS 2 BP 904 EP 912 DI 10.1086/383081 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822LC UT WOS:000221540100025 ER PT J AU Dyks, J Rudak, B Harding, AK AF Dyks, J Rudak, B Harding, AK TI On the methods of determining the radio emission geometry in pulsar magnetospheres SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : general; radiation mechanisms : nonthermal ID EMPIRICAL-THEORY; BEAMS; ALTITUDES; RADIATION; MODEL; POLARIZATION; DEPENDENCE; PATTERNS; REGIONS; SHAPE AB We present a modification of the relativistic phase shift method for determining the radio emission geometry from pulsar magnetospheres proposed by Gangadhara & Gupta. Our modification provides a method of determining radio emission altitudes that does not depend on the viewing geometry and does not require polarization measurements. We suggest application of the method to the outer edges of averaged radio pulse profiles to identify magnetic field lines associated with the edges of the pulse and, thereby, to test the geometric method based on the measurement of the pulse width at the lowest intensity level. We show that another relativistic method proposed by Blaskiewicz et al. provides upper limits for emission altitudes associated with the outer edges of pulse profiles. A comparison of these limits with the altitudes determined with the geometric method may be used to probe the importance of rotational distortions of the magnetic field and refraction effects in the pulsar magnetosphere. We provide a comprehensive discussion of the assumptions used in the relativistic methods. C1 NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Nicolaus Copernicus Astron Ctr, PL-87100 Torun, Poland. RP Dyks, J (reprint author), NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM jinx@milkyway.gsfc.nasa.gov; bronek@ncac.torun.pl; harding@twinkie.gsfc.nasa.gov RI Harding, Alice/D-3160-2012 NR 34 TC 66 Z9 66 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 2004 VL 607 IS 2 BP 939 EP 948 DI 10.1086/383587 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822LC UT WOS:000221540100029 ER PT J AU Stothers, RB AF Stothers, RB TI Magnetic influence on the stability of luminous stellar envelopes SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : magnetic fields; stars : oscillations; stars : variables : other; stars : Wolf-Rayet turbulence ID WOLF-RAYET STARS; BLUE VARIABLES; RADIATIVE INSTABILITY; TURBULENT TRANSPORT; CONVECTION; FIELDS; MODELS; PRESSURE; INTERIOR; DRIVEN AB Turbulence in the convective outer envelope of a luminous post-main-sequence star probably shreds any magnetic field that is buoyed up from the radiative region below and probably also generates small local magnetic fields. These magnetic structures would consist of well-tangled field lines, but could at most attain a steady state strength based on a near equipartition of their mean energy with the turbulent kinetic energy. Even assuming the maximum possible strength, the magnetic fields turn out to be too weak to affect significantly the dynamical stability of the envelope. This is a consequence as much of the low value of the field strength as of the fact that the field responds hydrodynamically to radial perturbations in the same manner as a gas with an adiabatic exponent of 4/3. Furthermore, fields this small are found to barely affect the radiative stability of the envelope. If the strongest magnetic components could safely reach the atmosphere, however, they might exert a noticeable effect there, or if the whole radiative interior were permeated with a strong magnetic field, very rapid mass loss at the surface might keep the outer layers strongly magnetic at all times before turbulence could break up the field lines. Otherwise, the bulk of the outer envelopes in stars such as yellow hypergiants, luminous blue variables, and hydrogen-poor Wolf-Rayet stars are not expected to be strongly magnetic. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Stothers, RB (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. NR 33 TC 2 Z9 2 U1 0 U2 1 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 2004 VL 607 IS 2 BP 999 EP 1002 DI 10.1086/383535 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822LC UT WOS:000221540100034 ER PT J AU Mori, K Tsunemi, H Katayama, H Burrows, DN Garmire, GP Metzger, AE AF Mori, K Tsunemi, H Katayama, H Burrows, DN Garmire, GP Metzger, AE TI An X-ray measurement of titan's atmospheric extent from its transit of the Crab nebula SO ASTROPHYSICAL JOURNAL LA English DT Article DE planets and satellites : individual (Titan); X-rays : general ID VOYAGER-1 RADIO-OCCULTATION; SPLIT-PIXEL EVENTS; SPATIAL-RESOLUTION; IMPROVEMENT AB Saturn's largest satellite, Titan, transited the Crab Nebula on 2003 January 5. We observed this astronomical event with the Chandra X-Ray Observatory. An "occultation shadow" has clearly been detected and is found to be larger than the diameter of Titan's solid surface. The difference gives a thickness for Titan's atmosphere of 880 +/- 60 km. This is the first measurement of Titan's atmospheric extent at X-ray wavelengths. The value measured is consistent with or slightly larger than those estimated from earlier Voyager observations at other wavelengths. We discuss the possibility of temporal variations in the thickness of Titan's atmosphere. C1 Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Osaka Univ, Grad Sch Sci, Dept Earth & Space Sci, Osaka 5600043, Japan. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mori, K (reprint author), Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. NR 16 TC 5 Z9 5 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 2004 VL 607 IS 2 BP 1065 EP 1069 DI 10.1086/383521 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822LC UT WOS:000221540100041 ER PT J AU Feng, H Zhang, SN Lou, YQ Li, TP AF Feng, H Zhang, SN Lou, YQ Li, TP TI X-ray triple rings around the M87 jets in the central Virgo Cluster SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : individual (Virgo); galaxies : individual (M87); galaxies : structure; X-rays : galaxies : clusters ID SPACE-TELESCOPE OBSERVATIONS; BLACK-HOLES; SN 1987A; COMPRESSIBLE FLUCTUATIONS; PERSEUS CLUSTER; XMM-NEWTON; REMNANT; FILAMENTS; CENTAURUS; EMISSION AB The Chandra X-ray data of the central Virgo Cluster are reexamined to reveal a triple-ring structure around the galaxy M87, reminiscent of the spectacular triple-ring pattern of the supernova SN 1987A in the Large Magellanic Cloud. In the sky plane, the two apparent smaller ellipses are roughly aligned along the M87 jets; the larger ring centers at the M87 nucleus and is likely a circle roughly perpendicular to the M87 jet. Certain similarities of these two triple-ring structures might hint at similar processes that operate in these two systems with entirely different sizes and mass scales. We suspect that a major merging event of two galaxies with nuclear supermassive black holes (SMBHs) might create such a triple-ring structure and drove acoustic and internal gravity waves far and near. The M87 jets are perhaps powered by a spinning SMBH resulting from this catastrophic merging event. C1 Tsing Hua Univ, Dept Engn Phys, Beijing 100084, Peoples R China. Tsing Hua Univ, Ctr Astrophys, Beijing 100084, Peoples R China. Tsing Hua Univ, Dept Phys, Beijing 100084, Peoples R China. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. Chinese Acad Sci, Inst High Energy Phys, Lab Particle Astrophys, Beijing 100039, Peoples R China. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China. RP Feng, H (reprint author), Tsing Hua Univ, Dept Engn Phys, Beijing 100084, Peoples R China. NR 38 TC 6 Z9 7 U1 0 U2 1 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 2004 VL 607 IS 2 BP L95 EP L98 DI 10.1086/422096 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822LD UT WOS:000221540200008 ER PT J AU Ghosh, KK Swartz, DA Tennant, AF Wu, KW Ramsey, BD AF Ghosh, KK Swartz, DA Tennant, AF Wu, KW Ramsey, BD TI ROSAT and ASCA observations of a narrow-line Seyfert 1 Galaxy RX J0136.9-3510: Blueshifted FeK alpha line and extended soft X-ray emission SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (RX J0136.9-3510); galaxies : nuclei; galaxies : Seyfert; X-rays : galaxies ID VELOCITY IONIZED OUTFLOW; ACTIVE GALAXIES; SPECTRA; VARIABILITY; ABSORPTION; CONTINUUM; QUASARS; SAMPLE; NLS1S; GAS AB RX J0136.9-3510 is an unusual narrow-line Seyfert 1 galaxy (NLS1). We have detected extended (similar to12" or similar to54 kpc at the source frame) soft X-ray emission in the ROSAT High Resolution Imager image, accounting for 20% of the total emission. We have also detected a highly blueshifted (7.6 keV in the source frame) Fe K alpha line in the ASCA Solid-State Imaging Spectrometer spectrum. This is the first detection of such a highly blueshifted emission line in a NLS1. Near-IR and far-IR studies indicate the presence of a possible starburst component in this NLS1. Physical models of the accretion and/or outflow and of the evolution of this NLS1 are discussed in the context of these results. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, NSSTC, Huntsville, AL 35805 USA. NASA, NSFC, NSSTC, Dept Space Sci, Huntsville, AL 35805 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. RP Ghosh, KK (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, NSSTC, Mail Code SD 50, Huntsville, AL 35805 USA. EM kajal.ghosh@msfc.nasa.gov; doug.swartz@msfc.nasa.gov; tennant@alph.msfc.nasa.gov; kw@mssl.ucl.ac.uk; brian.ramsey@msfc.nasa.gov NR 48 TC 8 Z9 8 U1 0 U2 1 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 1 PY 2004 VL 607 IS 2 BP L111 EP L114 DI 10.1086/421976 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822LD UT WOS:000221540200012 ER PT J AU Gu, MF Beiersdorfer, P Brown, GV Chen, H Boyce, KR Kelley, RL Kilbourne, CA Porter, FS Gu, MF AF Gu, MF Beiersdorfer, P Brown, GV Chen, H Boyce, KR Kelley, RL Kilbourne, CA Porter, FS Gu, MF TI Laboratory measurements of 3 -> 2 X-ray emission lines of Ne-like Ni xix SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; atomic processes; line : formation; X-rays : general ID HIGHLY CHARGED IONS; FE-XVII; GRATING SPECTROMETER; CROSS-SECTIONS; ELECTRON-BEAM; XMM-NEWTON; SPECTRUM; CHANDRA; MICROCALORIMETER; STRENGTHS AB The intensity ratios between 3 --> 2 emission lines in Ni XIX were measured on the Livermore electron beam ion trap (EBIT-I) with a flat-field grating spectrometer and the NASA/Goddard Space Flight Center X-ray microcalorimeter. The results are consistent with earlier measurements of Fe XVII and other Ne-like ions at Livermore and confirm the problems in the atomic modeling of the direct collisional excitation for Ne-like systems. C1 Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gu, MF (reprint author), Stanford Univ, Dept Phys, Varian Phys Room 108,382 Via Pueblo Mall, Stanford, CA 94305 USA. RI Porter, Frederick/D-3501-2012; Kelley, Richard/K-4474-2012 OI Porter, Frederick/0000-0002-6374-1119; NR 23 TC 22 Z9 22 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 2004 VL 607 IS 2 BP L143 EP L146 DI 10.1086/421975 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822LD UT WOS:000221540200020 ER PT J AU Zhao, JW Kosovichev, AG Duvall, TL AF Zhao, JW Kosovichev, AG Duvall, TL TI On the relationship between the rotational velocity and the field strength of solar magnetic elements SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : helioseismology; Sun : magnetic fields; Sun : rotation ID WHITE-LIGHT IMAGES; TIME-DISTANCE HELIOSEISMOLOGY; WAVE-LIKE PROPERTIES; CONVECTION ZONE; ACTIVE REGIONS; SUNSPOT GROUPS; FEATURES; RATES; FLUX; SUPERGRANULATION AB By tracking various solar surface tracers, previous studies have found that magnetic structures, such as plages and sunspots, rotate faster than the quiet solar regions. We investigate how the rotational speed of these magnetic features is related to their magnetic field strength. By use of near-surface horizontal velocities inferred from time-distance helioseismology, we have studied a few Carrington rotations covering the years 1997-2002, from near the solar minimum to the maximum. It is found that the residual rotational velocity of magnetic elements nearly linearly depends on their magnetic field strength: the stronger the magnetic field strength, the faster the magnetic elements rotate relative to the quiet solar regions. It is also found that the magnetic elements rotate faster in the solar maximum years than the elements of the same magnetic strength but in years with moderate solar activity. For all Carrington rotations studied, magnetic elements of the following polarity rotate faster than the leading polarity elements of the same magnetic strength. Possible interpretations of the observed relations are discussed. Prograde supergranular advection may cause the faster rotation of the following polarity elements. C1 Stanford Univ, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Zhao, JW (reprint author), Stanford Univ, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA. EM junwei@quake.stanford.edu RI Zhao, Junwei/A-1177-2007; Duvall, Thomas/C-9998-2012 NR 22 TC 30 Z9 30 U1 1 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 JUN 1 PY 2004 VL 607 IS 2 BP L135 EP L138 DI 10.1086/421974 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822LD UT WOS:000221540200018 ER PT J AU Zubko, V Dwek, E Arendt, RG AF Zubko, V Dwek, E Arendt, RG TI Interstellar dust models consistent with extinction, emission, and abundance constraints SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA Rumanian DT Article DE dust, extinction; infrared : ISM; ISM : abundances; ultraviolet : ISM ID SIZE DISTRIBUTION; INFRARED-EMISSION; GALACTIC-CENTER; TEMPERATURE-FLUCTUATIONS; ULTRAVIOLET EXTINCTION; OPTICAL-PROPERTIES; SWS OBSERVATIONS; SILICATE GRAINS; SINGLE CLOUDS; MILKY-WAY AB We present new interstellar dust models that have been derived by simultaneously fitting the far-ultraviolet to near-infrared extinction, the diffuse infrared (IR) emission and, unlike previous models, the elemental abundance constraints on the dust for different interstellar medium abundances, including solar, F and G star, and B star abundances. The fitting problem is a typical ill-posed inversion problem, in which the grain size distribution is the unknown, which we solve by using the method of regularization. The dust model contains various components: polycyclic aromatic hydrocarbons (PAHs), bare silicate, graphite, and amorphous carbon particles, as well as composite particles containing silicate, organic refractory material, water ice, and voids. The optical properties of these components were calculated using physical optical constants. As a special case, we reproduce the Li Draine results; however, their model requires an excessive amount of silicon, magnesium, and iron to be locked up in dust: about 50 ppm (atoms per million of H atoms), significantly more than the upper limit imposed by solar abundances of these elements, about 34, 35, and 28 ppm, respectively. A major conclusion of this paper is that there is no unique interstellar dust model that simultaneously fits the observed extinction, diffuse IR emission, and abundance constraints. We find several classes of acceptable interstellar dust models that comply with these constraints. The first class is identical in composition to the Li & Draine model, consisting of PAHs, bare graphite and silicate grains, but with a different size distribution that is optimized to comply with the abundance constraints. The second class of models contains in addition to PAHs bare graphite and silicate grains also composite particles. Other classes contain amorphous carbon instead of graphite particles, or no carbon at all, except for that in PAHs. All classes are consistent with solar and F and G star abundances but have greater difficulty fitting the B star carbon abundance, which is better fitted with the latter ( no carbon) models. Additional observational constraints, such as the interstellar polarization, or X-ray scattering may be able to discriminate between the various interstellar dust models. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Zubko, V (reprint author), Sci Syst & Applicat Inc, San Diego, CA USA. EM zubko@stars.gsfc.nasa.gov OI Arendt, Richard/0000-0001-8403-8548 NR 64 TC 297 Z9 298 U1 0 U2 10 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUN PY 2004 VL 152 IS 2 BP 211 EP 249 DI 10.1086/382351 PG 39 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823IT UT WOS:000221605200004 ER PT J AU Hogrefe, C Biswas, J Lynn, B Civerolo, K Ku, JY Rosenthal, J Rosenzweig, C Goldberg, R Kinney, PL AF Hogrefe, C Biswas, J Lynn, B Civerolo, K Ku, JY Rosenthal, J Rosenzweig, C Goldberg, R Kinney, PL TI Simulating regional-scale ozone climatology over the eastern United States: model evaluation results SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE regional-scale air quality modeling; model evaluation; regional climate modeling; interannual variability; map-typing analysis ID ETA-MODEL; SYSTEMS; PERFORMANCE; PREDICTIONS/; EMISSIONS; INVENTORY; EPISODES AB To study the potential impacts of climate change on air quality and public health over the eastern United States, a coupled global/regional-scale modeling system consisting of the NASA-Goddard Institute for Space Studies Atmosphere-Ocean model, the MM5 mesoscale meteorological model and the Community Multiscale Air Quality (CMAQ) model for air quality has been developed. Evaluation results of the modeling system used to simulate climate and ozone air quality over the eastern United States during the five summers of 1993-1997 are presented in this paper. The results indicate that MM5 and CMAQ capture interannual and synoptic-scale variability present in surface temperature and ozone observations in the current climate, while the magnitude Of fluctuations on shorter time scales is underestimated. A comparison of observed and predicted spatial patterns of daily maximum ozone concentrations shows best performance in predicting patterns for average and above-average ozone concentrations. The frequency distributions of the duration of extreme heat and ozone events show similar features for both model predictions and observations. Finally, application of a synoptic map-typing procedure reveals that the MM5/CMAQ system succeeded in simulating the average ozone concentrations associated with several frequent pressure patterns, indicating that the effects of synoptic-scale meteorology on ozone concentrations are captured by the modeling system. It is concluded that the GCM/MM5/CMAQ system is a suitable tool for the simulation of summertime surface temperature and ozone air quality conditions over the eastern United States in the present climate. (C) 2004 Elsevier Ltd. All rights reserved. C1 SUNY Albany, Atmospher Sci Res Ctr, Albany, NY 12203 USA. Columbia Univ, Mailman Sch Publ Hlth, New York, NY 10032 USA. Bur Air Qual Anal & Res, NYSDEC, Albany, NY 12233 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Hogrefe, C (reprint author), SUNY Albany, Atmospher Sci Res Ctr, 251 Fuller Rd, Albany, NY 12203 USA. EM chogrefe@dec.state.ny.us RI Kinney, Patrick/H-7914-2012; OI Civerolo, Kevin/0000-0003-1536-2664 NR 38 TC 64 Z9 69 U1 2 U2 16 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 2004 VL 38 IS 17 BP 2627 EP 2638 DI 10.1016/j.atmosenv.2004.02.033 PG 12 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 820CV UT WOS:000221365200003 ER PT J AU Lyons, TJ Kraft, NO Copley, GB Davenport, C Grayson, K Binder, H AF Lyons, TJ Kraft, NO Copley, GB Davenport, C Grayson, K Binder, H TI Analysis of mission and aircraft factors in g-induced loss of consciousness in the USAF: 1982-2002 SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE G-LOC incidence rates; crash rates; accident rates; fatality rates; accident epidemiology ID EXPERIENCE AB Introduction: Previous studies have used questionnaires to evaluate G-LOC incident rates in different aircraft types, but no studies of G-LOC-related incident, crash, and fatality rates in different aircraft types were found in a search of the literature. Methods: G-LOC events (including both incidents and crashes) for the fiscal years 1982 to 2002 were obtained from the USAF Safety Center. Aircraft sortie numbers were obtained for all aircraft that had a G-LOC event reported. Contingency table analysis and Chi-squared tests were used to evaluate differences in G-LOC rates. Results: Overall 559 G-LOC events occurred for a rate of 25.9 per million sorties (PMS), but event rates differed by almost two orders of magnitude between aircraft categories, being highest in basic training aircraft, intermediate in single crewmember fighters, and lowest in other aircraft types (p < 0.001). The proportion of events resulting in crashes was 30% in single-crewmember aircraft compared with 0.6% in trainers and other two-crewmember aircraft (p < 0.001). All of the crashes and fatalities occurred in aircraft occupied at the time by only a single crewmember. The crash fatality rate was 100% in attack aircraft, 73% in single-crewmember fighters, and zero in basic trainers (p < 0.05). The F-15 and F-16 aircraft did not have higher G-LOC rates than other single-seat fighters. Discussion: The data suggest that both crew complement and mission play a role in determining G-LOC rates. The data also suggest that G-LOC in an aircraft with a ground attack mission is more likely to result in a fatality. C1 Asian Off Aerosp Res & Dev, Minatu Ku, Tokyo 1060032, Japan. NASA, Ames Res Ctr, Human Factors Res & Technol Div, SJSU Fdn, Moffett Field, CA 94035 USA. HQ Air Force Safety Ctr, Res & Epidemiol Branch, Kirtland AFB, NM USA. FAA SW Reg Directorate, Ft Worth, TX USA. USAF, Inst Environm Safety & Occupat Hlth Risk Anal, Brooks City Base, TX USA. RP Lyons, TJ (reprint author), Asian Off Aerosp Res & Dev, Minatu Ku, 7-23-17 Roppongi, Tokyo 1060032, Japan. EM lyonst@aoard.af.mil NR 7 TC 10 Z9 13 U1 0 U2 0 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD JUN PY 2004 VL 75 IS 6 BP 479 EP 482 PG 4 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 824IV UT WOS:000221680900001 PM 15198271 ER PT J AU Navidi, M Evans, J Wolinsky, I Arnaud, SB AF Navidi, M Evans, J Wolinsky, I Arnaud, SB TI Calcium balance in mature male rats with unloaded hindlimbs SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE skeletal unloading; tail suspension; growth; calcium absorption; parathyroid hormone; 1,25-dihydroxyvitamin D ID DIETARY CALCIUM; VITAMIN-D; PARATHYROID-HORMONE; RODENT MODEL; METABOLISM; ABSORPTION; BONE; SPACEFLIGHT; WEIGHTLESSNESS; TRANSPORT AB Background: Calcium balances, regulated by the calcium endocrine system, are negative during spaceflight but have not been reported in flight simulation models using fully mature small animals. Methods:We conducted two calcium (Ca) balance studies in 6-mo-old male rats exposed to a model that unloads the hindlimbs (HU) for 4 wk. Control (C) and HU rats were fed diets with 0.5% Ca in the first and 0.1% Ca in the second study. Housing in metabolic cages enabled daily food and water intake measurements as well as collections of urine and fecal specimens. At necropsy, blood was obtained for measures of Ca-regulating hormones. Results: Both C and HU rats adjusted to housing and diets with decreases in body weight and negative Ca balances during the first week of each experiment. Thereafter, averages of Ca balances were more negative in the unloaded rats than controls: -8.1 vs. -1.6 mg d(-1) in rats fed 0.5% (p < 0.05). This difference was not due to urinary Ca excretion since it was lower in HU than C rats (1.27 +/- 0.51 mg (.) d(-1) vs. 2.35 +/- 0.82 mg (.) d(-1), p < 0.05). Fecal Ca in HU rats exceeded dietary Ca by 4-7%. Restricting dietary Ca to 0.1% was followed by an increase in serum 1,25-dihydroxyvitamin D (1,25-D) and greater intestinal Ca absorption than in rats fed 0.5% Ca. Ca balances in rats fed 0.1% Ca were also more negative in HU than C rats (-2.4 vs. -0.03 mg (.) d(-1), p < 0.05). Parathyroid hormone (PTH) was suppressed and 1,25-D increased in HU rats fed 0.5% Ca. C rats fed 0.1% Ca had increased PTH and 1,25-D was the same as in the HU group. Conclusion: After adaptation, Ca balances were more negative in mature male rats with unloaded hindlimbs than controls, an effect from increased secretion and loss of endogenous fecal Ca associated with increased 1,25-D in Careplete and Ca-restricted rats. C1 NASA, Ames Res Ctr, Gravitat Res Branch, Moffett Field, CA 94035 USA. Univ Houston, Houston, TX USA. RP Arnaud, SB (reprint author), NASA, Ames Res Ctr, Gravitat Res Branch, SLR 239-11, Moffett Field, CA 94035 USA. EM sarnaud@mail.arc.nasa.gov NR 30 TC 5 Z9 5 U1 0 U2 0 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD JUN PY 2004 VL 75 IS 6 BP 483 EP 488 PG 6 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 824IV UT WOS:000221680900002 PM 15198272 ER PT J AU Johnston, SL Campbell, MR Billica, RD Gilmore, SM AF Johnston, SL Campbell, MR Billica, RD Gilmore, SM TI Cardiopulmonary resuscitation in microgravity: Efficacy in the swine during parabolic flight SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE cardiopulmonary resuscitation; end-tidal CO2; space medicine; advanced cardiac life support; microgravity ID TIDAL CARBON-DIOXIDE; CARDIAC-ARREST; BLOOD-FLOW; CPR; GUIDE; COMPRESSION; OUTPUT; CO2 AB Introduction: The International Space Station will need to be as capable as possible in providing Advanced Cardiac Life Support (ACLS) and cardiopulmonary resuscitation (CPR). Previous studies with manikins in parabolic microgravity (0G) have shown that delivering CPR in microgravity is difficult. End tidal carbon dioxide (PetCO(2)) has been previously shown to be an effective non-invasive tool for estimating cardiac output during cardiopulmonary resuscitation. Animal models have shown that this diagnostic adjunct can be used as a predictor of survival when PetCO(2) values are maintained above 25% of pre-arrest values. Methods: Eleven anesthetized Yorkshire swine were flown in microgravity during parabolic flight. Physiologic parameters, including PetCO(2), were monitored. Standard ACLS protocols were used to resuscitate these models after chemical induction of cardiac arrest. Chest compressions were administered using conventional body positioning with waist restraint and unconventional vertical-inverted body positioning. Results: PetCO(2) values were maintained above 25% of both 1-G and 0-G pre-arrest values in the microgravity environment (33% inverted iota+/- 3 and 41 +/- 3). No significant difference between 1-G CPR and 0-G CPR was found in these animal models. Effective CPR was delivered in both body positions although conventional body positioning was found to be quickly fatiguing as compared with the vertical-inverted. Conclusions: Cardiopulmonary resuscitation can be effectively administered in microgravity (0G). Validation of this model has demonstrated that PetCO(2) levels were maintained above a level previously reported to be predictive of survival. The unconventional vertical-inverted position provided effective CPR and was less fatiguing as compared with the conventional body position with waist restraints. C1 NASA, Lyndon B Johnson Space Ctr, Med Operat Branch, Houston, TX 77058 USA. Paris Reg Med Ctr, Paris, TX USA. Wright State Univ, Dept Emergency Med, Kettering, OH USA. RP Johnston, SL (reprint author), NASA, Lyndon B Johnson Space Ctr, Med Operat Branch, Mail Code SD26,2101 NASA Rd, Houston, TX 77058 USA. NR 19 TC 6 Z9 6 U1 0 U2 0 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD JUN PY 2004 VL 75 IS 6 BP 546 EP 550 PG 5 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 824IV UT WOS:000221680900013 PM 15198283 ER PT J AU Platts, SH Ziegler, MG Waters, WW Mitchell, BM Meck, JV AF Platts, SH Ziegler, MG Waters, WW Mitchell, BM Meck, JV TI Midodrine prescribed to improve recurrent post-spaceflight orthostatic hypotension SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE venous return; microgravity; alpha-adrenergic agonist; ST-1059 AB Many astronauts exhibit post-spaceflight orthostatic hypotension due to inadequate norepinephrine release when in an upright posture. We hypothesized that an alpha(1)-adrenergic agonist, midodrine, would be an effective countermeasure. A female astronaut, who had problems with postflight orthostatic hypotension after a previous flight, consumed 10 mg midodrine after a subsequent flight, prior to her tilt test. Hemodynamic variables were compared between the two flights. Midodrine prevented severe falls in stroke volume, cardiac output and systolic pressure, and severe increases in heart rate without increasing vascular resistance, thus preventing orthostatic hypotension. This is the first report showing that midodrine has the potential to improve post-spaceflight orthostatic hypotension and suggesting that reduced venous return contributes to the etiology. C1 NASA, Lyndon B Johnson Space Ctr, Human Adaptat & Countermeasures Off, Space Life Sci Res Labs, Houston, TX 77058 USA. Wyle Labs Inc, Houston, TX USA. Univ Calif San Diego, San Diego, CA 92103 USA. Univ Space Res Assoc, Houston, TX USA. RP Meck, JV (reprint author), NASA, Lyndon B Johnson Space Ctr, Human Adaptat & Countermeasures Off, Space Life Sci Res Labs, SK32, Houston, TX 77058 USA. EM jmeck@ems.jsc.nasa.gov NR 10 TC 18 Z9 18 U1 1 U2 3 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD JUN PY 2004 VL 75 IS 6 BP 554 EP 556 PG 3 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 824IV UT WOS:000221680900015 PM 15198285 ER PT J AU Balazs, GH Chaloupka, M AF Balazs, GH Chaloupka, M TI Thirty-year recovery trend in the once depleted Hawaiian green sea turtle stock SO BIOLOGICAL CONSERVATION LA English DT Article DE green sea turtle; abundance; population recovery; French Frigate Shoals; Hawaii ID GREAT-BARRIER-REEF; POPULATION-DYNAMICS; BAYESIAN-INFERENCE; CHELONIA-MYDAS; MARINE TURTLES; GROWTH; RESIDENT; MODELS AB The green sea turtle is one of the long-lived species that comprise the charismatic marine megafauna. The green turtle has a long history of human exploitation with some stocks extinct. Here we report on a 30-year study of the nesting abundance of the green turtle stock endemic to the Hawaiian Archipelago. We show that there has been a substantial long-term increase in abundance of this once seriously depleted stock following cessation of harvesting since the 1970s. This population increase has occurred in a far shorter period of time than previously thought possible. There was also a distinct 3-4 year periodicity in annual nesting abundance that might be a function of regional environmental stochasticity that synchronises breeding behaviour throughout the Archipelago. This is one of the few reliable long-term population abundance time series for a large long-lived marine species, which are needed for gaining insights into the recovery process of long-lived marine species and long-term ecological processes. (C) 2003 Elsevier Ltd. All rights reserved. C1 Univ Queensland, Sch Econ, Brisbane, Qld 4072, Australia. Natl Marine Fisheries Serv, Pacific Isl Fisheries Sci Ctr, Honolulu, HI 96822 USA. RP Chaloupka, M (reprint author), Univ Queensland, Sch Econ, Brisbane, Qld 4072, Australia. EM m.chaloupka@mailbox.uq.edu.au NR 38 TC 102 Z9 116 U1 3 U2 39 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0006-3207 J9 BIOL CONSERV JI Biol. Conserv. PD JUN PY 2004 VL 117 IS 5 BP 491 EP 498 DI 10.1016/j.biocon.2003.08.008 PG 8 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 815BW UT WOS:000221018800004 ER PT J AU Shariff, K Ghosal, S Matouschek, A AF Shariff, K Ghosal, S Matouschek, A TI The force exerted by the membrane potential during protein import into the mitochondrial matrix SO BIOPHYSICAL JOURNAL LA English DT Article ID CHANNEL; TIM23; OUTER AB The force exerted on a targeting sequence by the electrical potential across the inner mitochondrial membrane is calculated on the basis of continuum electrostatics. The force is found to vary from 3.0 pN to 2.2 pN (per unit elementary charge) as the radius of the inner membrane pore (assumed aqueous) is varied from 6.5 to 12 Angstrom, its measured range. In the present model, the decrease in force with increasing pore width arises from the shielding effect of water. Since the pore is not very much wider than the distance between water molecules, the full shielding effect of water may not be present; the extreme case of a purely membranous pore without water gives a force of 3.2 pN per unit charge, which should represent an upper limit. When applied to mitochondrial import experiments on the protein barnase, these results imply that forces between 11 +/- 2 pN and 13.5 +/- 2.5 pN catalyze the unfolding of barnase in those experiments. A comparison of these results with unfolding forces measured using atomic force microscopy is made. C1 NASA, Ames Res Ctr, Phys Simulat & Modeling Off, Moffett Field, CA 94035 USA. Northwestern Univ, Dept Mech Engn, Evanston, IL 60208 USA. Northwestern Univ, Dept Biochem Mol Biol & Cell Biol, Evanston, IL 60208 USA. RP Shariff, K (reprint author), NASA, Ames Res Ctr, Phys Simulat & Modeling Off, MS 19-44, Moffett Field, CA 94035 USA. EM shariff@nas.nasa.gov RI Ghosal, Sandip/A-3534-2009; Ghosal, Sandip/B-7595-2009; Matouschek, Andreas/L-9379-2013; OI Ghosal, Sandip/0000-0001-6587-3716; Matouschek, Andreas/0000-0001-6016-2341; Shariff, Karim/0000-0002-7256-2497 FU NIGMS NIH HHS [R01 GM063004, R01GM63004] NR 20 TC 28 Z9 28 U1 0 U2 2 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD JUN PY 2004 VL 86 IS 6 BP 3647 EP 3652 DI 10.1529/biophysj.104.040865 PG 6 WC Biophysics SC Biophysics GA 829GK UT WOS:000222035200024 PM 15189861 ER PT J AU Ustin, SL Roberts, DA Gamon, JA Asner, GP Green, RO AF Ustin, SL Roberts, DA Gamon, JA Asner, GP Green, RO TI Using imaging spectroscopy to study ecosystem processes and properties SO BIOSCIENCE LA English DT Article DE remote sensing; landscape ecology; imaging spectroscopy; hyperspectral imaging; spectral analysis ID SANTA-MONICA MOUNTAINS; CANOPY WATER-CONTENT; CHLOROPHYLL CONTENT; LEAF BIOCHEMISTRY; AVIRIS DATA; BIOPHYSICAL PARAMETERS; ENDMEMBER SELECTION; ABSORPTION FEATURES; REFLECTANCE SPECTRA; OPTICAL-PROPERTIES AB Remote sensing data provide essential input for today's climate and ecosystem models. It is generally agreed that many model processes are not accurately depicted by current remotely sensed indices of vegetation and that new observational capabilities are needed at different spatial and spectral scales to reduce uncertainty. Recent advances in materials and optics have allowed the development of smaller, more stable, accurately calibrated imaging spectrometers that can quantify biophysical properties on the basis of the spectral absorbing and scattering characteristics of the land surface. Airborne and spaceborne imaging spectrometers, which measure large numbers (hundreds) of narrow spectral bands, are becoming more widely available from government and commercial sources; thus, it is increasingly feasible to use data from imaging spectroscopy for environmental research. In contrast to multispectral sensors, imaging spectroscopy produces quantitative estimates of biophysical absorptions, which can be used to improve scientific understanding of ecosystem functioning and properties. We present the recent advances in imaging spectroscopy and new capabilities for using it to quantify a range of ecological variables. C1 Univ Calif Davis, Dept Land Air & Water Resources, Davis, CA 95616 USA. Univ Calif Santa Barbara, Dept Geog, Santa Barbara, CA 93106 USA. Calif State Univ Los Angeles, Dept Biol & Microbiol, Los Angeles, CA 90032 USA. Carnegie Inst Washington, Dept Global Ecol, Stanford, CA 94305 USA. CALTECH, Jet Prop Lab, Observat Instruments Div, Pasadena, CA 91109 USA. RP Ustin, SL (reprint author), Univ Calif Davis, Dept Land Air & Water Resources, Davis, CA 95616 USA. EM slustin@ucdavis.edu RI Gamon, John/A-2641-2014; Asner, Gregory/G-9268-2013 OI Gamon, John/0000-0002-8269-7723; Asner, Gregory/0000-0001-7893-6421 NR 57 TC 267 Z9 276 U1 13 U2 91 PU AMER INST BIOLOGICAL SCI PI WASHINGTON PA 1444 EYE ST, NW, STE 200, WASHINGTON, DC 20005 USA SN 0006-3568 J9 BIOSCIENCE JI Bioscience PD JUN PY 2004 VL 54 IS 6 BP 523 EP 534 DI 10.1641/0006-3568(2004)054[0523:UISTSE]2.0.CO;2 PG 12 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 829CJ UT WOS:000222020700010 ER PT J AU Running, SW Nemani, RR Heinsch, FA Zhao, MS Reeves, M Hashimoto, H AF Running, SW Nemani, RR Heinsch, FA Zhao, MS Reeves, M Hashimoto, H TI A continuous satellite-derived measure of global terrestrial primary production SO BIOSCIENCE LA English DT Article DE net primary production; MODIS; carbon cycles; terrestrial remote sensing; biosphere ID NET PRIMARY PRODUCTION; ATMOSPHERIC CARBON-DIOXIDE; GROSS PRIMARY PRODUCTION; VEGETATION; CLIMATE; PHOTOSYNTHESIS; VARIABILITY; FORESTS; FLUXES; TRANSPIRATION AB Until recently, continuous monitoring of global vegetation productivity has not been possible because of technological limitations. This article introduces a new satellite-driven monitor of the global biosphere that regularly computes daily gross primary production (GPP) and annual net primary production. (NPP) at 1-kilometer (km) resolution over 109,782,756 km(2) of vegetated land surface. We summarize the history of global NPP science, as well as the derivation of this calculation, and current data production activity. Thefirst data on NPP from the EOS (Earth Observing System) MODIS (Moderate Resolution Imaging Spectroradiometer) sensor are presented with different types of validation. We offer examples of how this new type of data set can serve ecological science, land management, and environmental policy. To enhance the use of these data by non-specialists, we are now producing monthly anomaly maps for GPP and annual NPP that compare the current value with an 18-year average value for each pixel, clearly identifying regions where vegetation growth is higher or lower than normal. C1 Univ Montana, Numer Terradynam Simulat Grp, Dept Ecosyst & Conservat Sci, Missoula, MT 59812 USA. NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. RP Running, SW (reprint author), Univ Montana, Numer Terradynam Simulat Grp, Dept Ecosyst & Conservat Sci, Missoula, MT 59812 USA. EM swr@ntsg.umt.edu RI Zhao, Maosheng/G-5706-2010; Noojipady, Praveen/B-2511-2010 NR 61 TC 789 Z9 841 U1 33 U2 226 PU AMER INST BIOLOGICAL SCI PI WASHINGTON PA 1444 EYE ST, NW, STE 200, WASHINGTON, DC 20005 USA SN 0006-3568 J9 BIOSCIENCE JI Bioscience PD JUN PY 2004 VL 54 IS 6 BP 547 EP 560 DI 10.1641/0006-3568(2004)054[0547:ACSMOG]2.0.CO;2 PG 14 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 829CJ UT WOS:000222020700012 ER PT J AU Treuhaft, RN Law, BE Asner, GP AF Treuhaft, RN Law, BE Asner, GP TI Forest attributes from radar interferometric structure and its fusion with optical remote sensing SO BIOSCIENCE LA English DT Article DE remote sensing; carbon cycle; InSAR; lidar; optical remote sensing; forest ecology ID SAR INTERFEROMETRY; TROPICAL FOREST; CANOPY STRUCTURE; PONDEROSA PINE; BOREAL FOREST; LIDAR; TOPOGRAPHY; ECOSYSTEM; VALIDATION; SATELLITES AB The possibility of global, three-dimensional remote sensing of forest structure with interferometric synthetic aperture radar (InSAR) bears on important forest ecological processes, particularly the carbon cycle. InSAR supplements two-dimensional remote sensing with information in the vertical dimension. Its strengths in potential for global coverage complement those of lidar (light detecting and ranging), which has the potential for high-accuracy vertical profiles over small areas. InSAR derives its sensitivity to forest vertical structure from the differences in signals received by two, spatially separate radar receivers. Estimation of parameters describing vertical structure requires multiple-polarization, multiple-frequency, or multiple-baseline InSAR. Combining InSAR with complementary remote sensing techniques, such as hyperspectral optical imaging and lidar, can enhance vertical-structure estimates and consequent biophysical quantities of importance to ecologists, such as biomass. Future InSAR experiments will supplement recent airborne and spaceborne demonstrations, and together with inputs from ecologists regarding structure, they will suggest designs for future spaceborne strategies for measuring global vegetation structure. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Oregon State Univ, Coll Forestry, Corvallis, OR 97331 USA. Stanford Univ, Carnegie Inst, Dept Global Ecol, Stanford, CA USA. Stanford Univ, Dept Geog & Environm Sci, Stanford, CA USA. RP Treuhaft, RN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM robert.treuhaft@jpl.nasa.gov RI Asner, Gregory/G-9268-2013; OI Asner, Gregory/0000-0001-7893-6421; Law, Beverly/0000-0002-1605-1203 NR 50 TC 75 Z9 76 U1 3 U2 12 PU AMER INST BIOLOGICAL SCI PI WASHINGTON PA 1444 EYE ST, NW, STE 200, WASHINGTON, DC 20005 USA SN 0006-3568 J9 BIOSCIENCE JI Bioscience PD JUN PY 2004 VL 54 IS 6 BP 561 EP 571 DI 10.1641/0006-3568(2004)054[0561:FAFRIS]2.0.CO;2 PG 11 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 829CJ UT WOS:000222020700013 ER PT J AU Tselioudis, G Rossow, WB Gentilcore, AN Katzfey, J AF Tselioudis, G Rossow, WB Gentilcore, AN Katzfey, J TI The data integration for model evaluation web site - A one-stop shop for model evaluation SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article AB THE DATA INTEGRATION FOR MODEL EVALUATION WEB SITE: A ONE-STOP SHOP FOR MODEL EVALUATION This paper introduces the contents of the Global Energy and Water Experiment (GEWEX) Cloud System Study (GCSS) Data Integration for Model Evaluation (DIME) Web site. The Web site is a resource created for atmospheric modelers who want to run and test regional and cloud-resolving models in a variety of atmospheric conditions. It contains both datasets to initialize model runs and observations to test the output of those runs for a number of different field experiment campaigns. The evaluation data come mostly from large-scale satellite and meteorological datasets, extracted for the time period and region of the experiment. For more detailed evaluations, links are provided to the datasets collected by the experiments themselves. Climatological composites of certain atmospheric parameters are also provided, along with software that produces satellite-like parameters from model output. The intention of the DIME Web site creators is to collect in one place all the necessary tools needed to initialize, run, and produce meaningful evaluations of atmospheric model outputs. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Tselioudis, G (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM gtselioudis@giss.nasa.gov RI Rossow, William/F-3138-2015; Katzfey, Jack/K-1231-2012 OI Katzfey, Jack/0000-0002-0604-8860 NR 7 TC 1 Z9 1 U1 0 U2 2 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 JUN PY 2004 VL 85 IS 6 BP 830 EP + DI 10.1175/BAMS-85-6-830 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 834MU UT WOS:000222416000010 ER PT J AU Pomerantz, AE Ausfelder, F Zare, RN Huo, WM AF Pomerantz, AE Ausfelder, F Zare, RN Huo, WM TI Line strength factors for E,F-1 Sigma(+)(g)(v '=0, J '=J '')-X-1 Sigma(+)(g) (v '', J '') (2+1) REMPI transitions in molecular hydrogen SO CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE LA English DT Article DE hydrogen; spectroscopy; REMPI; line strength; multiphoton ID ENHANCED MULTIPHOTON IONIZATION; INTERNAL-STATE DISTRIBUTIONS; VIBRATIONALLY EXCITED H-2; COLLISION ENERGY; QUANTITATIVE-DETERMINATION; RECOMBINATIVE DESORPTION; ABINITIO CALCULATION; MATRIX-ELEMENTS; EXCITATION; HD AB Experimentally and theoretically determined line strengths are presented for E,F(1)Sigma(g)(+)(v' = 0, J' = J'') - X(1)Sigma(g)(+) (v'', J'') (2 + 1) REMPI transitions in H-2, HD, and D-2. The experimental technique employs a hot filament source of internally excited hydrogen that allows experimental determination of line strengths for the low rotational states of highly excited vibrational manifolds (v'' less than or equal to 4). The line strengths are found to depend only weakly on J'' for the states measured here, and theoretical results indicate that the line strengths depend strongly on v''. These values are combined with previously measured and calculated line strengths for these transitions (K.-D. Rinnen, M.A. Buntine, D.A.V. Kliner, R.N. Zare, and W.M. Huo. J. Chem. Phys. 95, 214 (1991)), resulting in a more complete compilation of REMPI line strengths for molecular hydrogen. C1 Stanford Univ, Dept Chem, Stanford, CA 94305 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Zare, RN (reprint author), Stanford Univ, Dept Chem, Stanford, CA 94305 USA. EM zare@stanford.edu RI Zare, Richard/A-8410-2009 NR 25 TC 14 Z9 14 U1 1 U2 6 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0008-4042 J9 CAN J CHEM JI Can. J. Chem.-Rev. Can. Chim. PD JUN PY 2004 VL 82 IS 6 BP 723 EP 729 DI 10.1139/V04-074 PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 861XA UT WOS:000224450700007 ER PT J AU Ramsay, B Flett, D Andersen, HS Gill, R Nghiem, S Bertoia, C AF Ramsay, B Flett, D Andersen, HS Gill, R Nghiem, S Bertoia, C TI Preparation for the operational use of RADARSAT-2 for ice monitoring SO CANADIAN JOURNAL OF REMOTE SENSING LA English DT Article ID SEA-ICE; POLARIMETRIC SIGNATURES; SAR AB Sea ice monitoring has been the most successful real-time operational application for RADARSAT-1 data. These data are used by several national ice services as a mainstay of their programs. Thus, the international sea ice community is looking forward to the future launch of RADARSAT-2. The RADARSAT-2 end-to-end system promises several technical enhancements beyond RADARSAT-1. These include multipolar/polarimetric data, improved data handling and processing and throughput, and a more streamlined ordering system. Ice versus water discrimination, sensitivity to surface topography and ridging, and enhanced iceberg detection capabilities are some of the improvements expected to result from the availability of like- and cross-polarized synthetic aperture radar (SAR) imagery. Beyond purely the information content, numerous challenges remain before the various improvements of the RADARSAT-2 system can be exploited operationally. Among these are handling the increased data volumes of multichannel data; developing new data display, visualization, and analysis techniques; operational scenarios and potential use of left- and right-looking to improve spatio-temporal coverage; improved order handling and satellite tasking; and acquisition planning and integration with other spaceborne SAR data (i.e., Envisat). In this paper we report on efforts underway at the Canadian, American, and Danish national ice services to address these elements necessary to be ready for the best operational use of RADARSAT-2 data. C1 Environm Canada, Canadian Ice Serv, Ottawa, ON K1A 0H3, Canada. Danish Inst Fundamental Metrol, DK-2100 Copenhagen, Denmark. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Ice Ctr, Washington, DC 20395 USA. RP Ramsay, B (reprint author), Environm Canada, Canadian Ice Serv, 373 Susse Dr,Block 3E, Ottawa, ON K1A 0H3, Canada. EM Bruce.ramsay@ec.gc.ca NR 13 TC 4 Z9 4 U1 0 U2 2 PU CANADIAN AERONAUTICS SPACE INST PI OTTAWA PA 1685 RUSSELL RD, UNIT 1-R, OTTAWA, ON K1G 0N1, CANADA SN 0703-8992 J9 CAN J REMOTE SENS JI Can. J. Remote Sens. PD JUN PY 2004 VL 30 IS 3 BP 415 EP 423 PG 9 WC Remote Sensing SC Remote Sensing GA 845PF UT WOS:000223256100019 ER PT J AU Katta, VR Takahashi, F Linteris, GT AF Katta, VR Takahashi, F Linteris, GT TI Suppression of cup-burner flames using carbon dioxide in microgravity SO COMBUSTION AND FLAME LA English DT Article DE fire-safety; fire-suppression; extinguishment; buoyancy; inhibitors; cup-burner ID JET DIFFUSION FLAMES; METHANE-AIR FLAMES; PREFERENTIAL DIFFUSION; INHIBITION; EXTINCTION; BUOYANT; SHAPES; LIMIT AB The extinguishment characteristics of CO2 as a fire-suppressing agent have been studied experimentally and numerically using a methane-air laminar co-flow diffusion flame stabilized on a cup burner. Direct numerical simulations of cup-burner flames under various gravitational forces were performed using a time-dependent, axisymmetric mathematical model with a detailed-chemical-kinetic mechanism for CH4/O-2 combustion. Experiments with cup-burner flames under normal-gravity (1g) conditions were performed for comparison purposes. Both the computed flicker frequency and the predicted critical concentration of CO2 for extinguishing the flame compared well with the respective quantities measured in the experiments. As the buoyancy force is reduced, the flicker frequency decreases, the flame diameter increases, the tip opens, and the base becomes vertical. It is predicted that the cup-burner flame ceases to flicker for gravitational forces corresponding to less than 0.5g. Numerical experiments revealed that radiative heat loss is predominantly responsible for flame quenching (opening) in the tip region under microgravity (0g) conditions. In contrast, 1g flames are affected only slightly by the radiative heat loss. Calculations are made by adding different amounts of CO2 to the air stream for obtaining the critical volume fraction of CO2 to extinguish 0g flames. The behavior is similar to that observed in 1g flames: the addition of CO2 destabilizes the flame base, which then moves downstream in search of a new stabilization location. For CO2 volume fractions greater than 19.1%, the flame base moves out of the computational area, as it cannot find a stabilization point within the domain. This critical concentration for the 0g flames is similar to 32% higher than that computed for the same flames under 1 g conditions. Calculations made by ignoring radiation for the limiting flame under 0g conditions yielded a stable flame. This study suggests that it is important to consider radiation heat losses when estimating the extinguishment limits of cup-burner flames in microgravity. (C) 2004 The Combustion Institute. Published by Elsevier Inc. All rights reserved. C1 Innovat Sci Solut Inc, Dayton, OH 45440 USA. NASA, Glenn Res Ctr, Natl Ctr Micrograv Res Fluids & Combust, Cleveland, OH 44135 USA. NIST, Fire Res Div, Gaithersburg, MD 20899 USA. RP Katta, VR (reprint author), Innovat Sci Solut Inc, 2766 Indian Ripple Rd, Dayton, OH 45440 USA. EM vrkatta@innssi.com NR 45 TC 25 Z9 26 U1 2 U2 13 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD JUN PY 2004 VL 137 IS 4 BP 506 EP 522 DI 10.1016/j.combustflame.2004.01.015 PG 17 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 828BZ UT WOS:000221949000008 ER PT J AU Nezlin, NP Oram, JJ DiGiacomo, PM Gruber, N AF Nezlin, NP Oram, JJ DiGiacomo, PM Gruber, N TI Sub-seasonal to interannual variations of sea surface temperature, salinity, oxygen anomaly, and transmissivity in Santa Monica Bay, California from 1987 to 1997 SO CONTINENTAL SHELF RESEARCH LA English DT Article DE sea surface temperature; salinity; oxygen; transparency; seasonal variations; interannual variability; Santa monica Bay; 33 degrees 45.6'-34 degrees 03.6'N; 118 degrees 44.4'-118 degrees 22.8'W ID 1982-1983 EL-NINO; EQUATORIAL PACIFIC-OCEAN; SOUTHERN-CALIFORNIA; CURRENT SYSTEM; NORTHEAST PACIFIC; WEST-COAST; INTRASEASONAL OSCILLATIONS; INTERDECADAL VARIABILITY; SATELLITE-OBSERVATIONS; UNITED-STATES AB While the basic hydrographic and circulation pattern of Santa Monica Bay (SMB) are relatively well known, the seasonal and interannual variations of these patterns are not well established nor are the mechanisms behind them well understood. We analyzed 10 years of hydrographic observations (1987-1997) in the surface layer of SMB off southern California to establish the mean seasonal cycle and to deduce patterns Of sub-seasonal to interannual variability of sea surface temperature, salinity, oxygen anomaly (the difference between oxygen concentration and its solubility), and transmissivity using empirical orthogonal functions and time-lagged cross-correlation methods. All four variables exhibit distinct seasonal variations, whose spatial distributions are a consequence of the interaction of bottom topography, vertical mixing, horizontal advection, freshwater discharge, and biological processes. The seasonal anomalies of all four parameters were estimated by removing the mean seasonal cycle; they exhibit three basic patterns: (1) an inshore/offshore gradient; (2) a balance between horizontal advection of the California Current from the northwest and the Southern California Countercurrent from the south; and (3) freshwater discharge from Ballona, Creek. Air/sea heat flux and vertical mixing are the main factors regulating the dynamics of sea surface temperature. Freshwater discharge centered at Ballona Creek is the principal factor creating the salinity pattern. The annual mean oxygen anomaly shows a substantial supersaturation across the entire SMB. The variations of oxygen anomalies are regulated by local biological productivity, vertical mixing, and horizontal transport. Vertical mixing influences water transparency by suspension of sediments and nutrient supply stimulating phytoplankton growth, A remarkably clear pattern of spatio-temporal variations of all parameters is observed in a relatively small basin; these variations are regulated by both local meteorological factors (air temperature, wind, atmospheric precipitation) and remote forcing, including the El Ni (n) over tildeo-Southern Oscillation cycle. (C) 2004 Elsevier Ltd. All rights reserved. C1 So Calif Coastal Water Res Project, Westminster, CA 92683 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nezlin, NP (reprint author), So Calif Coastal Water Res Project, 7171 Fenwick Lane, Westminster, CA 92683 USA. EM nikolayn@sccwrp.org RI DiGiacomo, Paul/F-5584-2010; Gruber, Nicolas/B-7013-2009 OI DiGiacomo, Paul/0000-0003-4550-1899; Gruber, Nicolas/0000-0002-2085-2310 NR 78 TC 10 Z9 11 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0278-4343 J9 CONT SHELF RES JI Cont. Shelf Res. PD JUN PY 2004 VL 24 IS 10 BP 1053 EP 1082 DI 10.1016/j.csr.2004.03.012 PG 30 WC Oceanography SC Oceanography GA 837AA UT WOS:000222596800001 ER PT J AU Larson, M Holmes, WA AF Larson, M Holmes, WA TI 2003 Space Cryogenics Workshop, 18-19 September 2003, Girdwood, Alaska SO CRYOGENICS LA English DT Editorial Material C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Larson, M (reprint author), Jet Prop Lab, Mail Stop 79-24,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM melora@squid.jpl.nasa.gov; Warren.A.Holmes@jpl.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 365 EP 366 DI 10.1016/j.cryogenics.2004.04.003 PG 2 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800001 ER PT J AU Tuttle, J Pourrahimi, S Shirron, P Canavan, E DiPirro, M Riall, S AF Tuttle, J Pourrahimi, S Shirron, P Canavan, E DiPirro, M Riall, S TI A 10 K magnet for space-flight ADRs SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE superconducting magnet; Nb3Sn; low-current react-then-wind AB Future NASA missions will include detectors cooled by adiabatic demagnetization refrigerators (ADRs) coupled with mechanical cryocoolers. A lightweight, low-current 10 K magnet would allow the interface between these devices to be at temperatures as high as 10 K, adding flexibility to the instrument design. We report oil the testing of a standard-technology Nb3Sn magnet and the development of a lightweight, low-current 10 K magnet. We also discuss the outlook for flying a 10 K magnet as part of an ADR system. (C) 2004 Elsevier Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Supercond Syst Inc, Waltham, MA 02453 USA. RP Tuttle, J (reprint author), NASA, Goddard Space Flight Ctr, Code 552, Greenbelt, MD 20771 USA. EM jim.tuttle@nasa.gov NR 5 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 383 EP 388 DI 10.1016/j.cryogenics.2004.02.007 PG 6 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800004 ER PT J AU Boyle, R AF Boyle, R TI On-orbit performance of the RHESSI cryocooler SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE cryocooler; Stirling; space cryogenics AB The Ramaty High Energy Solar Spectroscopic Imager (RHESSI) spacecraft was launched on February 5, 2002. With more than a year of operation on-orbit, its Sunpower M77 cryocooler continues to maintain the array of nine germanium detectors below 80 K. Trends have begun to emerge in cryocooler power and vibration, suggesting that the cooler's operating point is slowly changing. Possible causes are identified and discussed. (C) 2004 Elsevier Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Boyle, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM rob.boyle@nasa.gov NR 4 TC 4 Z9 5 U1 1 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 389 EP 393 DI 10.1016/j.cryogenics.2004.02.018 PG 5 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800005 ER PT J AU Bhandari, P Prina, M Bowman, RC Paine, C Pearson, D Nash, A AF Bhandari, P Prina, M Bowman, RC Paine, C Pearson, D Nash, A TI Sorption coolers using a continuous cycle to produce 20 K for the Planck flight mission SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE sorption cooler; cryo-cooler; Joule-Thomson AB Two sorption coolers using hydrogen as the working fluid are currently being fabricated and assembled for flight delivery by the Jet Propulsion Laboratory (JPL). Being vibration free, scalable and with the capability for the cold end to be remotely located from the warm spacecraft are the major advantages of this class of cryo-coolers. These systems have been designed to provide a total cooling capacity (per cooler) of 1 W at a cold end temperature less than 19 K. They will be used for the Planck surveyor mission (2007 launch). In this paper we present the level Of maturity of the hydrogen sorption cooler technology at JPL by describing the design and how it has been validated at the subsystem and system levels. (C) 2004 Elsevier Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bhandari, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM pradeep.bhandari@jpl.nasa.gov OI Bowman, Robert/0000-0002-2114-1713 NR 12 TC 32 Z9 33 U1 1 U2 3 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 395 EP 401 DI 10.1016/j.cryogenics.2004.02.022 PG 7 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800006 ER PT J AU Ross, RG Johnson, DL AF Ross, RG Johnson, DL TI Effect of gravity orientation on the thermal performance of Stirling-type pulse tube cryocoolers SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE pulse tube; orientation dependence; convection; gravity dependency AB The effect of angular orientation on the off-state conduction Of Pulse tube cryocoolers has been previously explored, as has the effect of orientation on the thermal performance of low-frequency (similar to2 Hz) GM-style pulse tube refrigerators. The significant effects that have been found are well explained by the presence of free convection that builds up in the hollow pulse tube when the hot end of the pulse tube is not higher than the cold end. This paper extends the investigation of angular orientation effects to the refrigeration performance of high frequency (similar to40 Hz) Stirling-type pulse tube cryocoolers typical of those used in long-life space applications. Strong orientation effects on the performance of such cryocoolers have recently been observed during system-level testing of both linear and U-tube type Pulse tubes. To quantify the angular dependency effects, data have been gathered on both U-tube and linear type pulse tubes of two different manufacturers as a function of orientation angle, cold-tip temperature, and compressor stroke. (C) 2004 Published by Elsevier Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ross, RG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM rgrossjr@jpl.nasa.gov NR 12 TC 7 Z9 9 U1 1 U2 3 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 403 EP 408 DI 10.1016/j.cryogenics.2004.02.020 PG 6 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800007 ER PT J AU Ross, RG AF Ross, RG TI Estimation of thermal conduction loads for structural supports of cryogenic spacecraft assemblies SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE thermal conduction loads; spacecraft cryogenic supports; launch loads; conductivity AB Early in the design process of cryogenic space systems there is a critical need for means of estimating the parasitic conduction loads associated with structural supports. In a mature design, the conduction loads can be computed with good accuracy based on the design details. However, for a generic trade study early in the design process, what is desired is a generic relationship (for typical launch loading conditions) between overall support conductance, the AT involved, and the supported mass. This work derives such a universal relationship by examining a variety of flight-proven designs for cryogenic structural supports and then normalizing the data given the known relationships between material conductivity and temperature, between launch acceleration level and assembly mass, between launch acceleration loads and stresses and required support-member cross-sections, and between support-member cross-section and conductive load. (C) 2004 Published by Elsevier Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ross, RG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM rgrossjr@jpl.nasa.gov NR 6 TC 5 Z9 5 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 421 EP 424 DI 10.1016/j.cryogenics.2004.02.019 PG 4 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800010 ER PT J AU Paine, CG AF Paine, CG TI Characterization of porous sinter materials as Joule-Thomson restrictors for the Planck sorption cooler SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE Joule-Thomson; porous flow restrictor; hydrogen AB The Planck sorption cooler cold end utilizes Joule-Thomson expansion of hydrogen to achieve temperatures below 18 K. Porous stainless steel sintered elements function as the J-T restriction. We report the flow characteristics of these porous flow restrictors, as a function of temperature over the range 19-300 K at constant pressure, and as a function A pressure at 1.4-5.5 MPa (200-800 psi) at constant temperatures of 19 and 300 K. The J-T restrictors were fabricated in three separate batches, using the same process and materials. Some comments are made regarding the uniformity of results from various fabrication batches. (C) 2004 Published by Elsevier Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91104 USA. RP Paine, CG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91104 USA. EM christopher.g.paine@jpl.nasa.gov NR 0 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 425 EP 429 DI 10.1016/j.cryogenics.2004.02.015 PG 5 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800011 ER PT J AU Quach, HP Chui, TCP AF Quach, HP Chui, TCP TI Low temperature magnetic properties of Metglas 2714A and its potential use as core material for EMI filters SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK AB Inductive filters to reduce electromagnetic interference (EMI) are commonly made by winding coils around a magnetic material with high permeability. This permeability should remain high at high frequencies, so that the impedance of the inductor made from it can be large to block off any high frequency EMI signals. Room temperature magnetic material like ferrite loses most of its permeability at low temperatures. Some low temperature materials like Cryoperm-10 are known to have high magnetic permeability. However, the permeability of all of them decreases to a low value at frequencies higher than a few hundred hertz due to eddy Current shielding of the magnetic field. We have measured the complex relative permeability of Metglas 2714A (also known as Magnaperm) at 4.2 K, and found that its magnitude is larger than 10,000 at frequencies up to 100 kHz. We also measured the magnetization noise density from this material using a SQUID magnetometer. We find that the noise density agrees well with the predictions of the fluctuation dissipation theorem. This implies that low temperature inductors and transformers with predictable noise characteristics can be designed for applications where the lowest noise is not a limiting factor of performance. For very low noise applications, a common mode filter can be made with this material, where the two input leads to a pre-amplifier are wound as a pair around the material, so that any magnetization noise is cancelled out. (C) 2004 Published by Elsevier Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chui, TCP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 79-24, Pasadena, CA 91109 USA. EM talso.c.chui@jpl.nasa.gov NR 5 TC 6 Z9 6 U1 1 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 445 EP 449 DI 10.1016/j.cryogenics.2004.01.006 PG 5 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800014 ER PT J AU Panzarella, C Plachta, D Kassemi, M AF Panzarella, C Plachta, D Kassemi, M TI Pressure control of large cryogenic tanks in microgravity SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE zero boil off; CFD; two-phase flow (C); vapor pressure (C); space cryogenics (F) AB This work studies the pressure control of a large cryogen storage tank in microgravity using a series of parametric numerical simulations. The complete governing equations in the liquid region are coupled to a lumped thermodynamic treatment of the vapor region. It is shown that even in microgravity buoyancy effects rapidly bring the vapor region Lip to the tank wall. Long-term pressurization studies show that natural convection still leads to considerable thermal stratification in the liquid. A subcooled liquid jet is used to control the pressure rise. At its lowest speed, the jet cannot penetrate far enough into the liquid region to cool the vapor because of retarding buoyancy forces. As the jet speed is increased, it is shown to be quite effective at disrupting the thermal stratification and reducing the tank pressure in a reasonable amount of time. (C) 2004 Elsevier Ltd. All rights reserved. C1 Ohio Aerosp Inst, Cleveland, OH 44142 USA. NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. RP Panzarella, C (reprint author), Ohio Aerosp Inst, 22800 Cedar Point Rd, Cleveland, OH 44142 USA. EM charles.h.panzarella@grc.nasa.gov NR 27 TC 7 Z9 13 U1 0 U2 7 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 475 EP 483 DI 10.1016/j.cryogenics.2004.03.009 PG 9 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800018 ER PT J AU Van Dresar, NT AF Van Dresar, NT TI An uncertainty analysis of the PVT gauging method applied to sub-critical cryogenic propellant tanks SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE gauging; low-gravity; cryogenic propellants AB The PVT (pressure. Volume, temperature) method of liquid quantity gauging in low-gravity is based oil gas law calculations assuming conservation of pressurant gas within the propellant tank and the pressurant supply bottle. There is interest in applying this method to cryogenic propellant tanks since the method requires minimal additional hardware or instrumentation. To use PVT with cryogenic fluids, a non-condensable pressurant gas (helium) is required. With cryogens, there will be a significant amount of propellant vapor mixed with the pressurant gas in the tank ullage. This condition, along with the high sensitivity of propellant vapor pressure to temperature, makes the PVT method susceptible to substantially greater measurement uncertainty than is the case with less volatile propellants. A conventional uncertainty analysis is applied to example cases of liquid hydrogen and liquid oxygen tanks. It appears that the PVT method may be feasible for liquid oxygen. Acceptable accuracy will be more difficult to obtain with liquid hydrogen. Published by Elsevier Ltd. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Van Dresar, NT (reprint author), NASA, Glenn Res Ctr, MS86-2, Cleveland, OH 44135 USA. EM neil.t.vandresar@grc.nasa.gov NR 5 TC 6 Z9 6 U1 1 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 515 EP 523 DI 10.1016/j.cryogenics.2004.01.002 PG 9 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800023 ER PT J AU Whitehouse, PL Shirron, PJ Kelley, RL AF Whitehouse, PL Shirron, PJ Kelley, RL TI The X-ray microcalorimeter spectromeller (XMS): a reference cryogenic instrument for constellation-X SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE microcalorimeter; ADR; cryocooler; cryostat; space cryogenics ID THERMAL LINK; CRYOCOOLERS AB The first two of four observatories in the constellation will be launched together in 2013 and followed a year later by the launch of the remaining pair. The four will independently orbit the Sun-Earth Lagrange point L2. An instrument compliment resides in the focal plane module (FPM) of each observatory 10 in from the optics module and consists of three hard X-ray telescope (HXT) detectors, a reflection grating spectrometer (RGS) focal plane CCD camera (RFC) and an X-ray microcalorimeter spectrometer (XMS). Instrument awards are scheduled for early 2006. The reference detector system for XMS is a 32 x 32 array of microcalorimetric superconducting transition edge sensors (TES) with SQUID based multiplexed readout and amplification. A multi-stage continuous ADR will provide the stable 50 mK desired for the TES array and a stable I K for the SQUID amplifiers while also lifting thermal parasitic and inefficiency loads to a 6 K cryocooler interface. The 6 K cryocooler is expected to emerge from the joint-project advanced cryocooler technology development program (ACTDP) in which Constellation-X is an active partner. Project preformulation activities are marked by extensive technology development necessitating early, but realistic, thermal and cooling load requirements for ADR and ACTDP-cryocooler design points. Such requirements are driven by the encompassing XMS cryostat and ultimately by the thermal environment imposed by the FPM It is further desired that the XMS instrument be able to operate horizontally in the laboratory, with a warm vacuum shell, during an extensive calibration regime. It is that highly integrated reference instrument (microcalorimeter, ADR, cryocooler and cryostat) that will be examined here. Published by Elsevier Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Whitehouse, PL (reprint author), NASA, Goddard Space Flight Ctr, Code 552, Greenbelt, MD 20771 USA. EM paul.l.whitehouse@nasa.gov RI Kelley, Richard/K-4474-2012 NR 12 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 543 EP 549 DI 10.1016/j.cryogenics.2004.03.011 PG 7 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800026 ER PT J AU Banks, S Breon, S Shirey, K AF Banks, S Breon, S Shirey, K TI AMS-02 cryocooler baseline configuration and EM qualification program SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE stirling cycle AB Four Sunpower M87N Stirling-cycle cryocoolers will be used to extend the lifetime of the Alpha Magnetic Spectrometer-02 (AMS-02) experiment. The cryocoolers will be mounted to the AMS-02 vacuum case using a structure that will thermally and mechanically decouple the cryocooler from the vacuum case while providing compliance to allow force attenuation using a passive balancer system. The cryocooler drive is implemented using a 60 Hz Pulse duration modulated Square wave. Details of the testing program, mounting assembly and drive scheme are presented. AMS-02 is a state-of-the-art particle physics detector containing a large superfluid helium-cooled Superconducting magnet. Highly sensitive detector plates inside the magnet measure a particle's speed, momentum, charge, and path. The AMS-02 experiment, which will be flown as an attached payload on the International Space Station, will study the properties and origin of cosmic particles and nuclei including antimatter and dark matter. Two engineering model cryocoolers have been under test at NASA Goddard since November 2001. Published by Elsevier Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Banks, S (reprint author), NASA, Goddard Space Flight Ctr, Code 552, Greenbelt, MD 20771 USA. EM stuart.banks@gsfc.nasa.gov NR 3 TC 2 Z9 2 U1 1 U2 5 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 551 EP 557 DI 10.1016/j.cryogenics.2004.02.013 PG 7 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800027 ER PT J AU DiPirro, M Canavan, E Shirron, P Tuttle, J AF DiPirro, M Canavan, E Shirron, P Tuttle, J TI Continuous cooling from 10 to 4 K using a toroidal ADR SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE adiabatic demagnetization; magnetic fields; cryocooler; space telescopes ID MAGNETIC REFRIGERATION; GD2O3; HEAT AB Future large infrared space telescopes will require cooling to 4 K to achieve background limited performance for submillimeter wavelengths. These observatories will require lifetimes of many years and will have relatively large cooling requirements making stored helium dewars impractical. We have designed and are building an adiabatic demagnetization refrigerator (ADR) for use in cooling relatively large loads (10-100 mW) at 4 K and rejecting that heat to a cryocooler operating at 10 K. The ADR magnet consists of eight short coils wired in series and arranged in a toroid to provide self shielding of its magnetic field. We will use gas gap heat switches to alternately connect the toroid to the cold load and the warm heat sink. A small continuous stage will maintain the cold end at 4 K while the main toroid is recycled. (C) 2004 Published by Elsevier Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP DiPirro, M (reprint author), NASA, Goddard Space Flight Ctr, Code 552, Greenbelt, MD 20771 USA. EM mike.dipirro@nasa.gov NR 19 TC 11 Z9 11 U1 0 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 559 EP 564 DI 10.1016/j.cryogenics.2004.01.005 PG 6 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800028 ER PT J AU Borders, J Morgante, G Prina, M Pearson, D Bhandari, P AF Borders, J Morgante, G Prina, M Pearson, D Bhandari, P TI Optimized autonomous operations of a 20 K space hydrogen sorption cryocooler SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE Joule Thomson coolers (E); Sorption coolers (E); Space cryogenics (F) AB A fully redundant hydrogen sorption cryocooler is being developed for the European Space Agency Planck mission, dedicated to the measurement of the temperature anisotropies of the cosmic microwave background radiation with unprecedented sensitivity and resolution [Advances in Cryogenic Engineering 45A (2000) 499]. In order to achieve this ambitious scientific task, this cooler is required to provide a stable temperature reference (similar to20 K) and appropriate cooling (similar to1 W) to the two instruments oil-board, with a flight operational lifetime of 18 months. During mission operations, communication with the spacecraft will be possible in a restricted time-window, not longer than 2 h/day. This implies the need for an operations control structure with the required robustness to safely perform autonomous procedures. The cooler performance depends oil many operating parameters (such as the temperatures of the pre-cooling stages and the warm radiator), therefore the operation control system needs the capability to adapt to variations of these boundary conditions, while maintaining safe operating procedures. An engineering bread board (EBB) cooler was assembled and tested to evaluate the behavior of the system under conditions simulating flight operations and the test data were used to refine and improve the operation control software. In order to minimize scientific data loss, the cooler is required to detect all possible failure modes and to autonomously react to them by taking the appropriate action in a rapid fashion. Various procedures and schemes both general and specific in nature were developed, tested and implemented to achieve these goals. In general, the robustness to malfunctions was increased by implementing all automatic classification of anomalies in different levels relative to the seriousness of the error. The response is therefore proportional to the failure level. Specifically, the start-up sequence duration was significantly reduced, allowing a much faster activation of the system, particularly useful in case of restarts after inadvertent shutdowns arising from malfunctions in the spacecraft. The capacity of the system to detect J-T plugs was increased to the point that the cooler is able to autonomously identify actual contaminants clogging from gas flow reductions due to off-nominal operating conditions. Once a plug is confirmed, the software autonomously energizes, and subsequently turns off, a J-T defrost heater until the clog is removed, bringing the system back to normal operating conditions. In this paper, all the cooler Operational Modes are presented, together with the description of the logic structure of the procedures and the advantages they produce for the operations. (C) 2004 Published by Elsevier Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CNR, IASF, Sez Bologna, I-40129 Bologna, Italy. RP Borders, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM james.w.borders@jpl.nasa.gov OI Morgante, Gianluca/0000-0001-9234-7412 NR 6 TC 2 Z9 3 U1 0 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 EI 1879-2235 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 565 EP 573 DI 10.1016/j.cryogenics.2004.03.012 PG 9 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800029 ER PT J AU Mustafi, S Banks, S Shirey, K Breon, S AF Mustafi, S Banks, S Shirey, K Breon, S TI Qualifying the Sunpower M87N cryocooler for operation in the AMS-02 magnetic field SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE space cryogenics (F); stirling (E); magnetic measurements (D); electromagnetic phenomena (C); magnetic (A) AB The Alpha Magnetic Spectrometer-02 (AMS-02) experiment uses a superfluid helium dewar to cool a large Superconducting magnet. The outer vapor-cooled shields of the dewar are to be held at 80 K by four Sunpower M87N cryocoolers. These cryocoolers have magnetic components that might interact with the external applied field generated by the superconducting magnet, thereby degrading the cryocoolers' performance. Engineering models of the Sunpower M87 have been qualified for operation in a magnetic environment similar to the AMS-02 magnetic environment. Although there was no noticeable performance degradation at field levels that were comparable to AMS-02 field levels, there appears to be a small performance degradation at higher field levels. It was theorized that there were three possible issues related to these performance losses at high magnetic fields: (i) induced piston rubbing on the cylinder wall due to forces and torques Oil the linear motor due to the applied magnetic fields; (ii) magnetic hysteretic and/or eddy current damping of the balancer due to its motion in the applied magnetic fields; (iii) inductance losses in motor due to the applied magnetic field. The experiments conducted at the Massachusetts Institute of Technology (MIT) cyclotron facility in June 2002 were designed to test these. Tests were performed over a range of field levels that were lower, comparable, and higher than the field levels that the cryocoolers will experience in the AMS-02 operating environment. This paper describes the experiments and the inferences derived from them. (C) 2004 Published by Elsevier Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mustafi, S (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM shuvo.mustafi@nasa.gov NR 3 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 575 EP 580 DI 10.1016/j.cryogenics.2004.02.006 PG 6 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800030 ER PT J AU Shirron, P Canavan, E DiPirro, M Francis, J Jackson, M Tuttle, J King, T Grabowski, M AF Shirron, P Canavan, E DiPirro, M Francis, J Jackson, M Tuttle, J King, T Grabowski, M TI Development of a cryogen-free continuous ADR for the constellation-X mission SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE magnetic refrigeration; adiabatic demagnetization; cryocooler; space telescopes AB Constellation-X is a multi-satellite X-ray astronomy mission presently being planned for launch in the 2010 time frame. Each of four identical satellites will contain a telescope and instruments for imaging and spectroscopic analysis of hard and soft X-rays. The X-ray Microcalorimeter Spectrometer (XMS) instrument will use arrays of microcalorimeters to detect X-rays with energies from 0.2 to 6 keV. To achieve the desired energy resolution of 2 eV, the detectors will be cooled to 50 mK. The projected cooling power requirement is approximately 5 muW. In order to meet the mission lifetime requirement of 6 years (with a goal of 10 years), a mechanical cryocooler will be used to provide a heat sink for the low temperature cooler. In this paper we discuss the development of a continuous adiabatic demagnetization refrigerator (CADR) that meets the cooling requirements of the XMS instrument. The four-stage CADR presently being tested can operate continuously at 50 mK using a 4.2 K helium bath as a heat sink. Its cooling power of 6 muW at 50 mK exceeds the XMS requirement, and its peak heat rejection rate is less than 7 mW. Details of the CADR's design and operation, as well as the development program leading up to a flight-qualified instrument, are discussed. (C) 2004 Published by Elsevier Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. SSAI, Lanham, MD 20706 USA. RP Shirron, P (reprint author), NASA, Goddard Space Flight Ctr, Code 552, Greenbelt, MD 20771 USA. EM peter.shirron@gsfc.nasa.gov NR 9 TC 35 Z9 36 U1 2 U2 9 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 581 EP 588 DI 10.1016/j.cryogenics.2003.11.011 PG 8 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800031 ER PT J AU Prina, M Borders, J Bhandari, P Morgante, G Pearson, D Paine, C AF Prina, M Borders, J Bhandari, P Morgante, G Pearson, D Paine, C TI Low-heat input cryogenic temperature control with recuperative heat-exchanger in a Joule Thomson cryocooler SO CRYOGENICS LA English DT Article; Proceedings Paper CT 20th Space Cryogenics Workshop CY SEP 18-19, 2003 CL Girdwood, AK DE Joule Thomson coolers (E); heat exchangers (E); space cryogenics (F) AB The control of cryogenic temperatures is usually accomplished by a passive stage, exploiting the combined effect of a thermal mass connected to a thermal resistance; by an active control, often of a PID type, based on the combination of a dedicated sensor, a heater and a controller; or by a combination of the two. Such a system typically uses a controlled stage that is isolated from the source of the fluctuations by a thermal isolator. Controlled insertion of heat into this stage counters the temperature fluctuations reaching the stage. Inherent to this type of system is the insertion of heat into the controlled stage that eventually reaches the cold end of the cooler, reducing the net heat lift available. The larger the thermal isolation, the smaller the reduction of the net heat lift, but with the attendant increase in the interface temperature. Any scheme that can reduce the penalty associated with the loss of heat lift or the temperature offset would be attractive in terms of cooler performance. If the cooler system has a recuperative heat exchanger between the coldest heat sink and a higher temperature precooler, a different approach can be used. In this paper we describe a novel control approach capable of passively damping low frequency fluctuatious, requiring minimal reduction of cooler heat lift and minimal temperature increase of the cold end interface. This alternative scheme is based on the idea of controlling the temperature of a section of the recuperative heat exchanger between the coldest precooler and the cold end of the cooler and it has been tested on a 20 K hydrogen sorption JT cooler. (C) 2004 Elsevier Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CNR, IASF, Sez Bologna, I-40129 Bologna, Italy. RP Prina, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM mauro.prina@jpl.nasa.gov OI Morgante, Gianluca/0000-0001-9234-7412 NR 6 TC 1 Z9 1 U1 1 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD JUN-AUG PY 2004 VL 44 IS 6-8 BP 595 EP 601 DI 10.1016/j.cryogenics.2004.02.021 PG 7 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 832XA UT WOS:000222299800033 ER PT J AU Close, F Fong Garvin, J Magee, P Henbest, N Foing, B Couper, H AF Close, F Fong Garvin, J Magee, P Henbest, N Foing, B Couper, H TI Human spaceflight in the UK: The cost of non-participation - Discussion SO EARTH MOON AND PLANETS LA English DT Editorial Material C1 Univ Oxford, Oxford OX1 2JD, England. NASA, Greenbelt, MD 20771 USA. Royal United Hosp, Bath BA1 3NG, Avon, England. ESA, F-75738 Paris, France. RP Close, F (reprint author), Univ Oxford, Oxford OX1 2JD, England. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PD JUN PY 2004 VL 94 IS 3-4 BP 174 EP 176 PG 3 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 990IJ UT WOS:000233736100003 ER PT J AU Garvin, JB AF Garvin, JB TI The science behind the Vision for US Space Exploration: The value of a human-robotic partnership SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT Royal-Astronomical-Society Specialist Discussion Meeting CY DEC 10, 2004 CL London, ENGLAND SP Royal Astron Soc DE Apollo; human space exploration; Mars; Moon; robotic space exploration AB The Vision for U.S. Space Exploration offers new opportunities for aggressively increasing the pace of scientific discoveries across the Solar System by empowering an on-site partnership between humans and robotics, enhanced by new technology-enabled capabilities. In particular, the early emphasis of this new Vision will be on development of new scientific activities on the Moon, and later on Mars. Integration of in situ traditional science activities with creative new types of applied scientific research on the Moon and Mars is a key ingredient in the US Vision. The Apollo era record of achievement involving human exploration is particularly informative, as it demonstrates the accelerated pace of scientific discovery and understanding that resulted from human "on site" activities, however briefly, on planetary surfaces. An example of how integrated human and robotic exploration can enable breakthrough science on the planet Mars is provided in order to illustrate these points. The scientific opportunities associated with the Vision for US Space Exploration are many, and with the incorporation of human-based capabilities on the Moon and Mars, an accelerated pace of discovery and understanding will be possible. C1 NASA Headquarters, Washington, DC 20546 USA. RP Garvin, JB (reprint author), NASA Headquarters, 300 E St SW, Washington, DC 20546 USA. EM james.b.garvin@nasa.gov NR 6 TC 5 Z9 5 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PD JUN PY 2004 VL 94 IS 3-4 BP 221 EP 231 DI 10.1007/s11038-005-9050-x PG 11 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 990IJ UT WOS:000233736100009 ER PT J AU Riggan, PJ Tissell, RG Lockwood, RN Brass, JA Pereira, JAR Miranda, HS Miranda, AC Campos, T Higgins, R AF Riggan, PJ Tissell, RG Lockwood, RN Brass, JA Pereira, JAR Miranda, HS Miranda, AC Campos, T Higgins, R TI Remote measurement of energy and carbon flux from wildfires in Brazil SO ECOLOGICAL APPLICATIONS LA English DT Article DE carbon flux; Cerrado; extended-dynamic-range imaging spectrometer; fire temperature; heat flux; infrared imaging; radiant flux density; remote sensing; slash fire; tropical forest; tropical savanna; wildfire ID FIRE AB Temperature, intensity, spread, and dimensions of fires burning in tropical savanna and slashed tropical forest in central Brazil were measured for the first time by remote sensing with an infrared imaging spectrometer that was designed to accommodate the high radiances of wildland fires. Furthermore, the first in situ airborne measurements of sensible heat and carbon fluxes in fire plumes were combined with remote measurements of flame properties to provide consistent remote-sensing-based estimators of these fluxes. These estimators provide a means to determine rates of fuel consumption and carbon emission to the atmosphere by wildland fires as required for assessments of fire impacts on regional air pollution or global emissions of greenhouse gases. Observed fires developed complex fire-line geometry and thermal structure, even as average whole-fire temperatures varied little. Flame temperatures sometimes exceeded 1600 K along the leading edge of actively spreading fire lines, yet >90% of the radiant energy from observed fires was associated with temperatures of 830-1440 K. Fire in a partially slashed forest encompassed a high-intensity flaming front and a trailing reach of residual combustion extending 400 m. Fire fronts in tropical savanna typically formed with little depth and a high proportion of their radiant flux density associated with high temperatures due to low levels of residual combustion. Measured fires had such low and variable radiance compared with that of a blackbody of comparable temperature as to preclude the use of fire radiance at a single wavelength as a measure of fire intensity or temperature. One-half of the radiant flux density from a measured savanna fire was associated with values of a combined emissivity-fractional-area parameter <0.091 m(2)/m(2); for a slash fire this fraction was associated with values <0.37 m(2)/m(2). Observations reported here show wildland fires to be so complex and dynamic as to require frequent high-resolution measurements over their course and duration in order to specify their effects in the environment; an understanding of global fire impacts may require such measurements over a large sample of individual fires. C1 US Forest Serv, Pacific SW Res Stn, Forest Fire Lab, Riverside, CA 92507 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Inst Brasileiro Meio Ambiente & Recurosos Nat Rec, Brasilia, DF, Brazil. Univ Brasilia, Dept Ecol, Brasilia, DF, Brazil. Natl Ctr Atmospher Res, Atmospher Technol Div, Boulder, CO 80307 USA. Simco Elect Inc, Moffett Field, CA 94035 USA. RP Riggan, PJ (reprint author), US Forest Serv, Pacific SW Res Stn, Forest Fire Lab, Riverside, CA 92507 USA. EM priggan@fs.fed.us RI Miranda, Heloisa/H-7833-2015 NR 21 TC 43 Z9 44 U1 2 U2 14 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 1707 H ST NW, STE 400, WASHINGTON, DC 20006-3915 USA SN 1051-0761 J9 ECOL APPL JI Ecol. Appl. PD JUN PY 2004 VL 14 IS 3 BP 855 EP 872 DI 10.1890/02-5162 PG 18 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA 831DS UT WOS:000222174000018 ER PT J AU Hurtt, GC Dubayah, R Drake, J Moorcroft, PR Pacala, SW Blair, JB Fearon, MG AF Hurtt, GC Dubayah, R Drake, J Moorcroft, PR Pacala, SW Blair, JB Fearon, MG TI Beyond potential vegetation: combining lidar data and a height-structured model for carbon studies SO ECOLOGICAL APPLICATIONS LA English DT Article DE aboveground biomass; carbon fluxes; Costa Rica; ecosystem demography; ecosystem modeling; La Selva; lidar; regional carbon stocks; remote sensing ID TROPICAL RAIN-FOREST; INTERANNUAL CLIMATE VARIABILITY; LARGE-FOOTPRINT LIDAR; LASER SCANNER DATA; ABOVEGROUND BIOMASS; CANOPY STRUCTURE; CLOSED-CANOPY; LAND-COVER; ECOSYSTEM; DIOXIDE AB Carbon estimates from terrestrial ecosystem models are limited by large uncertainties in the current state of the land surface. Natural and anthropogenic disturbances have important and lasting influences on ecosystem structure and fluxes that can be difficult to detect or assess with conventional methods. In this study, we combined two recent advances in remote sensing and ecosystem modeling to improve model carbon stock and flux estimates at a tropical forest study site at La Selva, Costa Rica (10degrees25' N, 84degrees00' W). Airborne lidar remote sensing was used to measure spatial heterogeneity in the vertical structure of vegetation. The ecosystem demography model (ED) was used to estimate the consequences of this heterogeneity for regional estimates of carbon stocks and fluxes. Lidar data provided substantial constraints on model estimates of both carbon stocks and net carbon fluxes. Lidar-initialized ED estimates of above ground biomass were within 1.2% of regression-based approaches, and corresponding model estimates of net carbon fluxes differed substantially from bracketing alternatives. The results of this study provide a promising illustration of the power of combining lidar data on vegetation height with a height-structured ecosystem model. Extending these analyses to larger scales will require the development of regional and global lidar data sets, and the continued development and application of height structured ecosystem models. C1 Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Univ New Hampshire, Dept Nat Resources, Durham, NH 03824 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. Univ Georgia, DB Warnell Sch Forest Resources, Athens, GA 30602 USA. Harvard Univ, Dept Organism & Evolutionary Biol, Cambridge, MA 02138 USA. Princeton Univ, Dept Ecol & Evolutionary Biol, Princeton, NJ 08544 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hurtt, GC (reprint author), Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. EM george.hurtt@unh.edu RI Hurtt, George/A-8450-2012; Blair, James/D-3881-2013; Beckley, Matthew/D-4547-2013 NR 73 TC 66 Z9 68 U1 4 U2 31 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 1707 H ST NW, STE 400, WASHINGTON, DC 20006-3915 USA SN 1051-0761 J9 ECOL APPL JI Ecol. Appl. PD JUN PY 2004 VL 14 IS 3 BP 873 EP 883 DI 10.1890/02-5317 PG 11 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA 831DS UT WOS:000222174000019 ER PT J AU Carls, MG Holland, LG Short, JW Heintz, RA Rice, SD AF Carls, MG Holland, LG Short, JW Heintz, RA Rice, SD TI Monitoring polynuclear aromatic hydrocarbons in aqueous environments with passive low-density polyethylene membrane devices SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE polyethylene membrane devices; semipermeable membrane devices; polynuclear aromatic hydrocarbon; environmental monitoring ID WEATHERED CRUDE-OIL; EXXON-VALDEZ OIL; FISH EMBRYOS; MODEL; RIVER; CONTAMINANTS; ACCUMULATION; SENSITIVITY; POLLUTANTS; INDUCTION AB Low-density polyethylene membranes, typically filled with triolein, have been previously deployed as passive environmental samplers designed to accumulate nonpolar hydrophobic chemicals from water, sediments, and air. Hydrocarbons in such samplers, known as semipermeable membrane devices (SPMDs), diffuse through pores in the membranes and are trapped in the central hydrocarbon matrix, mimicking uptake by living organisms. Here, we describe laboratory and field verification that low-density polyethylene membrane devices (PEMDs) without triolein provide reliable, relatively inexpensive, time-integrated hydrocarbon sampling from water. For comparison, polynuclear aromatic hydrocarbon (PAH) uptake in SPMDs and pink salmon eggs also was studied. Total concentrations of PAH accumulated by PEMDs were highly correlated with concentrations in water (r(2) greater than or equal to 0.99) and linear over the range tested (0-17 mug/L). Higher-molecular-mass PAH preferentially accumulated in PEMDs and in pink salmon eggs, but the source of oil in PEMDs remained identifiable. Accumulations of PAH were highly similar to those in SPMDs. The PEMDs retained approximately 78% of accumulated total PAH for 40 d in clean water. Thus, a simple plastic membrane can be conveniently used for environmental monitoring, particularly during situations in which contaminant concentrations are low (in the parts-per-billion range), variable, and intermittent. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP Carls, MG (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. EM mark.carls@noaa.gov NR 31 TC 36 Z9 37 U1 1 U2 15 PU SETAC PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3367 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD JUN PY 2004 VL 23 IS 6 BP 1416 EP 1424 DI 10.1897/03-395 PG 9 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 826JO UT WOS:000221825600008 PM 15376527 ER PT J AU Scharf, FS Manderson, JP Fabrizio, MC Pessutti, JP Rosendale, JE Chant, RJ Bejda, AJ AF Scharf, FS Manderson, JP Fabrizio, MC Pessutti, JP Rosendale, JE Chant, RJ Bejda, AJ TI Seasonal and interannual patterns of distribution and diet of bluefish within a middle Atlantic bight estuary in relation to abiotic and biotic factors SO ESTUARIES LA English DT Article ID THE-YEAR BLUEFISH; MENHADEN BREVOORTIA-TYRANNUS; DRUM SCIAENOPS-OCELLATUS; HUDSON RIVER ESTUARY; POMATOMUS-SALTATRIX; CHESAPEAKE-BAY; STRIPED BASS; JUVENILE BLUEFISH; AGE-0 BLUEFISH; NEW-YORK AB Seasonal and interannual patterns in the spatial distribution of bluefish (Pomatomus saltatrix) within a Middle Atlantic Bight estuary were examined using multipanel gillnets fished biweekly at 14 fixed stations in the Sandy Hook Bay-Navesink River estuary during May November of 1998 and 1999. To characterize habitats along the estuarine gradient, we measured several abiotic and biotic variables concurrently with gillnet sampling. juvenile (age-0 and age-1+) bluefish were captured regularly during both years along with large numbers of Atlantic menhaden (Brevoortia tyranmus), which were confirmed by diet analyses to be bluefish's primary forage species. The date of initial appearance of age-0 bluefish and menhaden in the estuary varied between years and may have been related to interannual differences in seawater temperatures on the continental shelf during spring. Delayed estuarine arrival of prey fishes may have contributed to variability in bluefish diets between years. Within the estuary, bluefish spatial distributions were consistent across seasons and years: bluefish were most common in areas associated with high concentrations of suspended materials and the presence of menhaden. Community analyses also indicated habitat overlap between bluefish and menhaden. Spatial distribution patterns revealed the consistent occurrence of piscivorous bluefish in shallow estuarine habitats that retained suspended materials and aggregated prey fishes. Foraging success of bluefish and other estuarine piscivores may be closely linked with the availability of these productive habitats, highlighting the need for future study of biological interactions and the governing physical processes. C1 NOAA, Behav Ecol Branch, NE Fisheries Sci Ctr, Natl Marine & Fisheries Serv,James J Howard Marin, Highlands, NJ 07732 USA. Rutgers State Univ, Inst Marine & Coastal Sci, New Brunswick, NJ 08901 USA. RP Scharf, FS (reprint author), Univ N Carolina, Dept Biol Sci, 601 S Coll Rd, Wilmington, NC 28403 USA. EM scharff@uncw.edu OI Fabrizio, Mary/0000-0002-6115-5490 NR 42 TC 20 Z9 20 U1 1 U2 7 PU ESTUARINE RES FEDERATION PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 USA SN 0160-8347 J9 ESTUARIES JI Estuaries PD JUN PY 2004 VL 27 IS 3 BP 426 EP 436 DI 10.1007/BF02803535 PG 11 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 832UK UT WOS:000222292500007 ER PT J AU Deboer, D Ackermann, R Blitz, L Bock, D Bower, G Davis, M Dreher, J Engargiola, G Fleming, M Keleta, G Harp, G Lugten, J Tarter, J Thornton, D Wadefalk, N Weinreb, S Welch, WJ AF Deboer, D Ackermann, R Blitz, L Bock, D Bower, G Davis, M Dreher, J Engargiola, G Fleming, M Keleta, G Harp, G Lugten, J Tarter, J Thornton, D Wadefalk, N Weinreb, S Welch, WJ TI The Allen Telescope Array SO EXPERIMENTAL ASTRONOMY LA English DT Article; Proceedings Paper CT Square Kilometre Array Meeting (SKA) CY JUL, 2004 CL Penticton, CANADA DE array technology; radio astronomy; SETI AB The Allen Telescope Array, a joint project between the SETI Institute and the Radio Astronomy Laboratory at the University of California Berkeley, is currently under development and construction at the Hat Creek Radio Observatory in northern California. It will consist of 350 6.1-m offset Gregorian antennas in a fairly densely packed configuration, with minimum baselines of less than 10 m and a maximum baseline of about 900 m. The dual-polarization frequency range spans from about 500 MHz to 11 GHz, both polarizations of which are transported back from each antenna. The first generation processor will provide 32 synthesized beams of 104 MHz bandwidth, eight at each of four tunings, as well as outputs for a full-polarization correlator at two of the tunings at the same bandwidth. This paper provides a general description of the Allen Telescope Array. C1 SETI Inst, Mountain View, CA 94043 USA. Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Deboer, D (reprint author), SETI Inst, 2035 Landings Dr, Mountain View, CA 94043 USA. EM ddeboer@seti.org NR 8 TC 5 Z9 5 U1 0 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0922-6435 J9 EXP ASTRON JI Exp. Astron. PD JUN PY 2004 VL 17 IS 1-3 BP 19 EP 34 DI 10.1007/s10686-005-4193-3 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 963LN UT WOS:000231805900004 ER PT J AU Bardin, J Weinreb, S Bagri, D AF Bardin, J Weinreb, S Bagri, D TI Local oscillator distribution using a geostationary satellite SO EXPERIMENTAL ASTRONOMY LA English DT Article; Proceedings Paper CT Square Kilometre Array Meeting (SKA) CY JUL, 2004 CL Penticton, CANADA DE hydrogen maser; LO distribution; local oscillator; two-way satellite time transfer; TWTT; TWSTT AB A satellite communication system suitable for distribution of local oscillator reference signals for a widely spaced microwave array has been developed and tested experimentally. The system uses a round-trip correction method to remove effects of atmospheric fluctuations and radial motion of the satellite. This experiment was carried out using Telstar-5, a commercial Ku-band geostationary satellite. A typical Ku-band satellite has uplink and downlink capacity at 14-14.5 GHz and 11.7-12.2 GHz, respectively. For this initial experiment, both earth stations were located at the same site to facilitate direct comparison of the received signals. The local oscillator reference frequency was chosen to be 300 MHz and was sent as the difference between two Ku-band tones. The residual error after applying the round trip correction has been measured to be better than 3 ps for integration times ranging from 1 to 2000 s. For integration times greater than 500 s, the system outperforms a pair of hydrogen masers with the limitation believed to be ground-based equipment phase stability. The idea of distributing local oscillators using a geostationary satellite is not new; several researchers experimented with this technique in the eighties, but the achieved accuracy was 3 to 100 times worse than the present results. Since then, the cost of both leased satellite bandwidth and the Ku-band ground equipment has dropped substantially and the performance of various components has improved. An important factor is the availability of narrow bands which can be leased on a communications satellite. We lease three 100 kHz bands at approximately one hundredth the cost of a full 36 MHz-wide transponder. Further tests of the system using terminals separated by large distances and comparison tests with two hydrogen masers and radio interferometry of astronomical objects are needed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Bardin, J (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM joseph.c.bardin@jpl.nasa.gov NR 9 TC 1 Z9 2 U1 0 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0922-6435 J9 EXP ASTRON JI Exp. Astron. PD JUN PY 2004 VL 17 IS 1-3 BP 193 EP 199 DI 10.1007/s10686-005-0032-9 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 963LN UT WOS:000231805900019 ER PT J AU Bunton, JD Navarro, R AF Bunton, JD Navarro, R TI DSN deep-space array-based network beamformer SO EXPERIMENTAL ASTRONOMY LA English DT Article; Proceedings Paper CT Square Kilometre Array Meeting (SKA) CY JUL, 2004 CL Penticton, CANADA DE beamformer; correlator; Deep Space Network; FX correlator; filterbank ID FREQUENCY-DOMAIN; ALGORITHM AB NASA is proposing a new receiving facility that needs to beamform broadband signals from hundreds of antennas. This is a similar problem to SKA beamforming with the added requirement that the processing should not add significant noise or distortion that would interfere with processing spacecraft telemetry data. The proposed solution is based on an FX correlator architecture and uses oversampling polyphase filterbanks to avoid aliasing. Each beamformer/correlator module processes a small part of the total bandwidth for all antennas, eliminating interconnection problems. Processing the summed frequency data with a synthesis polyphase filterbank reconstructs the time series. Choice of suitable oversampling ratio, and analysis and synthesis filters can keep aliasing below -39 dB while keeping the passband ripple low. This approach is readily integrated into the currently proposed SKA correlator architecture. C1 CSIRO, ICT Ctr, Epping, NSW 1710, Australia. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bunton, JD (reprint author), CSIRO, ICT Ctr, POB 76, Epping, NSW 1710, Australia. EM john.bunton@csiro.au RI Bunton, John/A-4944-2008 NR 11 TC 2 Z9 3 U1 0 U2 5 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0922-6435 J9 EXP ASTRON JI Exp. Astron. PD JUN PY 2004 VL 17 IS 1-3 BP 299 EP 305 DI 10.1007/s10686-005-2866-6 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 963LN UT WOS:000231805900029 ER PT J AU Keller, LP Messenger, S Flynn, GJ Clemett, S Wirick, S Jacobsen, C AF Keller, LP Messenger, S Flynn, GJ Clemett, S Wirick, S Jacobsen, C TI The nature of molecular cloud material in interplanetary dust SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID DIFFUSE INTERSTELLAR-MEDIUM; POLYCYCLIC AROMATIC-HYDROCARBONS; MACROMOLECULAR ORGANIC-MATTER; SOLAR-SYSTEM; ISOTOPIC COMPOSITION; INFRARED-SPECTROSCOPY; DEUTERIUM ENRICHMENT; PRIMITIVE METEORITES; NITROGEN ISOTOPE; ICE ANALOGS AB Eight interplanetary dust particles (IDPs) exhibiting a wide range of H and N isotopic anomalies have been studied by transmission electron microscopy, x-ray absorption near-edge structure spectroscopy, and Fourier-transform infrared spectroscopy. These anomalies are believed to have originated during chemical reactions in a cold molecular cloud that was the precursor to the Solar System. The chemical and mineralogical studies reported here thus constitute direct studies of preserved molecular cloud materials. The H and N isotopic anomalies are hosted by different hydrocarbons that reside in the abundant carbonaceous matrix of the IDPs. Infrared measurements constrain the major deuterium (D) host in the D-enriched IDPs to thermally labile aliphatic hydrocarbon groups attached to macromolecular material. Much of the large variation observed in D/H in this suite of IDPs reflects the variable loss of this labile component during atmospheric entry heating. IDPs with elevated N-15/N-14 ratios contain N in the form of amine (-NH2) functional groups that are likely attached to other molecules such as aromatic hydrocarbons. The host of the N isotopic anomalies is not as readily lost during entry heating as the D-rich material. Infrared analysis shows that while the organic matter in primitive anhydrous IDPs is similar to that observed in acid residues of primitive chondritic meteorites, the measured aromatic: aliphatic ratio is markedly lower in the IDPs. Copyright (C) 2004 Elsevier Ltd. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. NASA, Lockheed Martin, Houston, TX 77058 USA. SUNY Coll Plattsburgh, Dept Phys, Plattsburgh, NY 12901 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. Washington Univ, Space Sci Lab, St Louis, MO 63130 USA. RP Keller, LP (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code SR, Houston, TX 77058 USA. EM lindsay.p.keller@jsc.nasa.gov RI Jacobsen, Chris/E-2827-2015 OI Jacobsen, Chris/0000-0001-8562-0353 NR 69 TC 91 Z9 91 U1 2 U2 13 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 BP 2577 EP 2589 DI 10.1016/j.gca.2003.10.044 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 823UG UT WOS:000221638200013 ER PT J AU Bada, JL Grunthaner, F Mathies, R AF Bada, JL Grunthaner, F Mathies, R TI AstroBioLab: A mobile in situ subsurface biotic and soil reactivity analytical laboratory SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NASA, Jet Propuls Lab, Pasadena, CA 91109 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. EM jbada@ucsd.edu; Frank.J.Grunthaner@jpl.nasa.gov; rich@zinc.cchem.berkeley.edu NR 0 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 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A807 EP A807 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923401451 ER PT J AU Buch, A Glavin, DP Szopa, C Meunier, D Coscia, D Sternberg, R Cabane, M Navaro-Gonzalez, R Raulin, F Mahaffy, PR AF Buch, A Glavin, DP Szopa, C Meunier, D Coscia, D Sternberg, R Cabane, M Navaro-Gonzalez, R Raulin, F Mahaffy, PR TI Amino and carboxylic acids in a Mars soil analogue from the Atacama desert SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Paris 12, CNRS, LISA, F-94010 Creteil, France. CNRS, Serv Aeron, F-91371 Verrieres Le Buisson, France. Natl Autonomous Univ Mexico, Lab Quim Plasma & Estudio Planetarios, Mexico City 04510, DF, Mexico. RI Mahaffy, Paul/E-4609-2012; Glavin, Daniel/D-6194-2012; szopa, cyril/C-6865-2015 OI Glavin, Daniel/0000-0001-7779-7765; szopa, cyril/0000-0002-0090-4056 NR 2 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 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A806 EP A806 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923401449 ER PT J AU Conrad, PG Lane, AL Bhartia, R AF Conrad, PG Lane, AL Bhartia, R TI Non-contact rapid detection of chemical biosignatures in rock and sediment SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM conrad@jpl.nasa.gov; arthur.l.lane@jpl.nasa.gov; rbhartia@jpl.nasa.gov NR 0 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 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A804 EP A804 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923401445 ER PT J AU Flynn, GJ Keller, LP Sutton, SR AF Flynn, GJ Keller, LP Sutton, SR TI Submicron scale element mapping in IDPs: Constraints on dust formation and aqueous alteration SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen C1 SUNY Coll Plattsburgh, Plattsburgh, NY 12901 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Chicago, CARS, Chicago, IL 60637 USA. Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. EM george.fynn@plattsburgh.edu NR 0 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 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A730 EP A730 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923401311 ER PT J AU Glavin, DP Cleaves, HJ Schubert, M Aubrey, A Buch, A Mahaffy, PR Bada, JL AF Glavin, DP Cleaves, HJ Schubert, M Aubrey, A Buch, A Mahaffy, PR Bada, JL TI Detecting pyrolysis products from bacteria in a Mars soil analogue SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. CNRS, UMR5161, F-69364 Lyon, France. EM daniel.p.glavin@nasa.gov RI Mahaffy, Paul/E-4609-2012; Glavin, Daniel/D-6194-2012 OI Glavin, Daniel/0000-0001-7779-7765 NR 4 TC 0 Z9 0 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A807 EP A807 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923401450 ER PT J AU Hubbard, C Black, S Coleman, M AF Hubbard, C Black, S Coleman, M TI Source zone dynamics in the Rio Tinto, SW Spain SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen C1 Univ Reading, Sch Human & Environm Sci, Reading RG6 2AH, Berks, England. CALTECH, Jet Prop Lab, Pasadena, CA USA. EM c.g.hubbard@reading.ac.uk RI Black, Stuart/A-1099-2014; Hubbard, Christopher/J-6150-2014 OI Black, Stuart/0000-0003-1396-4821; Hubbard, Christopher/0000-0002-8217-8122 NR 3 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 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A452 EP A452 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923400787 ER PT J AU Jones, JH AF Jones, JH TI Dry magmatism on Mars SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen ID SHERGOTTY METEORITE; WATER C1 NASA, Lyndon B Johnson Space Ctr, SR, Houston, TX 77058 USA. EM jjones2@ems.jsc.nasa.gov NR 4 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 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A734 EP A734 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923401319 ER PT J AU Kuhlman, KR Kelly, TF AF Kuhlman, KR Kelly, TF TI Three-dimensional nanoanalysis of a metamorphic magnetite SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen ID CRYSTALS C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Imago Sci Instruments Corp, Madison, WI 53719 USA. EM kkuhlman@jpl.nasa.gov; tkelly@imago.com NR 4 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 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A107 EP A107 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923400162 ER PT J AU La Duc, MT Benardini, JN Lubarsky, M Newcombe, DA Venkateswaran, K AF La Duc, MT Benardini, JN Lubarsky, M Newcombe, DA Venkateswaran, K TI Extremely perseverant microbes isolated from a deep-sea hydrothermal vent system SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. EM kjvenkat@jpl.nasa.gov NR 0 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 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A326 EP A326 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923400551 ER PT J AU Love, GD Bowden, SA Snape, CE Jahnke, LL Summons, RE AF Love, GD Bowden, SA Snape, CE Jahnke, LL Summons, RE TI Rapid screening of microbial cultures and organic macromolecules to assess biomarker lipid contents using catalytic hydropyrolysis SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen C1 MIT, EAPS, Cambridge, MA 02139 USA. Univ Newcastle Upon Tyne, CENGEO, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England. Univ Nottingham, SChEME, Nottingham NG7 2RD, England. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM glove@mit.edu; Colin.Snape@nottingham.ac.uk; Linda.L.Jahnke@nasa.gov; rsummons@mit.edu NR 1 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 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A242 EP A242 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923400399 ER PT J AU Maule, JG Steele, A McKay, DS AF Maule, JG Steele, A McKay, DS TI Life detection on a chip SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen C1 Carnegie Inst Washington, Geophys Lab, Washington, DC 20015 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. EM j.maule@gl.ciw.edu NR 3 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 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A805 EP A805 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923401447 ER PT J AU Mittlefehldt, DW AF Mittlefehldt, DW TI Chemical and O isotopic correlations among chondrite groups SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen ID SOLAR-SYSTEM C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. EM david.w.mittlefehldt@nasa.gov NR 3 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 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A764 EP A764 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923401375 ER PT J AU Pidgeon, R Nemchin, A van Bronswijk, W Meyer, C Compston, W Williams, I AF Pidgeon, R Nemchin, A van Bronswijk, W Meyer, C Compston, W Williams, I TI 3.9Ga to 4.3Ga zircons in lunar breccia 14321: Evidence for a complex source for ejecta from the Imbrium impact SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen C1 Curtin Univ Technol, Perth, WA 6001, Australia. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT, Australia. EM r.pidgeon@curtin.edu.au RI SHRIMP, ANU/F-5312-2011 NR 2 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 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A748 EP A748 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923401345 ER PT J AU Schroder, C Klingelhofer, G Morris, RV Bernhardt, B Rodionov, D de Souza, PA Renz, F AF Schroder, C Klingelhofer, G Morris, RV Bernhardt, B Rodionov, D de Souza, PA Renz, F TI Mossbauer spectroscopy on Mars and its potential contribution in the search for extraterrestrial life SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen C1 Univ Mainz, Inst Anorgan & Analyt Chem, D-6500 Mainz, Germany. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Von Hoerner & Sulger GmbH, Schwetzingen, Germany. IKI, Inst Space Res, Moscow, Russia. Companhia Vale do Rio Doce, Pelletizing Dept, Vitoria, Brazil. EM schroedc@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 0 TC 0 Z9 0 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A808 EP A808 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923401453 ER PT J AU Tronnes, RG Johansen, TS Karlsson, H Williams, AJ Imsland, P Gronvold, K Waight, T Brandon, AD Lee, CT Graham, DW AF Tronnes, RG Johansen, TS Karlsson, H Williams, AJ Imsland, P Gronvold, K Waight, T Brandon, AD Lee, CT Graham, DW TI NE Atlantic mantle geochemistry: New insights from volcanic flank zones in Iceland and Jan Mayen SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen C1 Univ Iceland, Nord Volcanol Inst, IS-101 Reykjavik, Iceland. Univ Oslo, Geol Museum, N-0316 Oslo, Norway. GEOMAR, Kiel, Germany. Texas Tech Univ, Lubbock, TX 79409 USA. SUERC, E Kilbride, Lanark, Scotland. Univ Copenhagen, DK-1168 Copenhagen, Denmark. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Rice Univ, Houston, TX 77251 USA. Oregon State Univ, Corvallis, OR 97331 USA. EM rgt@hi.is; tjohansen@geomar.de; hal.karlsson@ttu.edu; Alice.Williams@glg.ed.ac.uk; todw@geo.geol.ku.dk; alan.d.brandon@nasa.gov; ctlee@rice.edu RI Waight, Tod/A-8262-2010 OI Waight, Tod/0000-0003-2601-1202 NR 0 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 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A701 EP A701 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923401257 ER PT J AU Yamaguchi, KE Johnson, CM Beard, BL Ohmoto, H AF Yamaguchi, KE Johnson, CM Beard, BL Ohmoto, H TI Iron-sulfur-carbon contents and isotope systematics of 2.7 Ga shallow and deep facies black shales from the Hamersley Basin, Australia SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 14th Annual V M Goldschmidt Conference CY JUN 05-11, 2004 CL Univ Copenhagen, Copenhagen, DENMARK SP European Assoc Geochem, Geochem Soc, Geochem Soc Japan, Mineralog Soc Amer HO Univ Copenhagen C1 IFREE, JAMSTEC, Yokosuka, Kanagawa, Japan. Univ Wisconsin, Dept Geol & Geophys, Madison, WI 53706 USA. NASA, Astrobiol Inst, Washington, DC 20546 USA. Penn State Univ, Astrobiol Res Ctr, University Pk, PA 16802 USA. EM kosei@geology.wisc.edu; clarkj@geology.wisc.edu; beardb@geology.wise.edu; ohmoto@geosc.psu.edu NR 3 TC 1 Z9 1 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2004 VL 68 IS 11 SU S BP A795 EP A795 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 827TH UT WOS:000221923401431 ER PT J AU Kimes, D Ullah, A Levine, E Nelson, R Timmins, S Weiss, S Bollinger, ME Blaisdell, C AF Kimes, D Ullah, A Levine, E Nelson, R Timmins, S Weiss, S Bollinger, ME Blaisdell, C TI Relationships between pediatric asthma and socioeconomic/urban variables in Baltimore, Maryland SO HEALTH & PLACE LA English DT Article DE pediatric asthma; socioeconomic status; urban characteristics; spatial analysis ID AFRICAN-AMERICAN CHILDREN; ARTIFICIAL NEURAL-NETWORK; INNER-CITY CHILDREN; CHILDHOOD ASTHMA; UNITED-STATES; AIR-POLLUTION; RISK-FACTORS; EMERGENCY; URBAN; PREVALENCE AB Spatial relationships between clinical data for pediatric asthmatics (hospital and emergency department utilization rates), and socioeconomic and urban characteristics in Baltimore City were analyzed with the aim of identifying factors that contribute to increased asthma rates. Socioeconomic variables and urban characteristics derived from satellite data explained 95% of the spatial variation in hospital rates. The proportion of families headed by a single female was the most important variable accounting for 89% of the spatial variation. Evidence suggests that the high rates of hospital admissions and emergency department (ED) visits may partially be due to the difficulty of single parents with limited resources managing their child's asthma condition properly. This knowledge can be used for education towards mitigating ED and hospital events in Baltimore City. Published by Elsevier Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Decis Syst Technol, Greenbelt, MD 20770 USA. Univ Maryland, Sch Med, Dept Epidemiol & Prevent Med, Baltimore, MD 21201 USA. Univ Maryland, Sch Pharm, Dept Pharmaceut Hlth Serv Res, Baltimore, MD 21201 USA. Univ Maryland, Sch Med, Div Pediat Pulmonol & Allergy, Baltimore, MD 21201 USA. RP Kimes, D (reprint author), NASA, Goddard Space Flight Ctr, Mail Stop 923, Greenbelt, MD 20771 USA. EM dan@pika.gsfc.nasa.gov NR 45 TC 13 Z9 14 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1353-8292 J9 HEALTH PLACE JI Health Place PD JUN PY 2004 VL 10 IS 2 BP 141 EP 152 DI 10.1016/S1353-8292(03)00054-6 PG 12 WC Public, Environmental & Occupational Health SC Public, Environmental & Occupational Health GA 819DQ UT WOS:000221293900003 PM 15019908 ER PT J AU Edwards, DL Hubbs, WS Wertz, GE Hoppe, DT Nehls, MK Hollerman, WA Gray, PA Semmel, CL AF Edwards, DL Hubbs, WS Wertz, GE Hoppe, DT Nehls, MK Hollerman, WA Gray, PA Semmel, CL TI Electron radiation effects on candidate solar sail material SO HIGH PERFORMANCE POLYMERS LA English DT Article; Proceedings Paper CT 9th International Symposium on Materials in a Space Environment CY JUN 16-20, 2003 CL NOORDWIJK, NETHERLANDS DE sails; radiation effects; in-space propulsion; light pressure AB Solar sailing is a unique form of propulsion in which a spacecraft gains momentum from incident photons. Solar sails are not limited by reaction mass and provide continual acceleration, reduced only by the lifetime of the lightweight film in the space environment and the distance to the Sun. Once thought to be difficult or impossible, solar sailing has come out of science fiction and into the realm of possibility Any spacecraft using this propulsion method would need to deploy a thin sail that could be as large as many kilometres in extent. The availability of strong, ultra lightweight, and radiation-resistant materials will determine the future of solar sailing. The National Aeronautics and Space Administration's (NASA) Marshall Space Flight Center (MSFC) is concentrating research into the utilization of ultra lightweight materials for spacecraft propulsion. The Space Environmental Effects Team at MSFC is actively characterizing candidate solar sail material to evaluate the thermo-optical and mechanical properties after exposure to space environmental effects. This paper will describe the irradiation of candidate solar sail materials to energetic electrons, in vacuum, in an effort to determine the in-space operational survivability of several candidate sail materials. Results from this research indicate that the candidate sail materials can survive significant doses of electron radiation while under high uniaxial. stress. C1 NASA, MSFC, Marshall Space Flight Ctr, AL 35812 USA. Univ SW Louisiana, Dept Phys, Lafayette, LA 70504 USA. ICRC, Marshall Space Flight Ctr, AL 35812 USA. QUALIS, Marshall Space Flight Ctr, AL 35812 USA. RP Hollerman, WA (reprint author), NASA, MSFC, ED31, Marshall Space Flight Ctr, AL 35812 USA. EM hollerman@louisiana.edu RI Hollerman, William/F-5943-2011 NR 10 TC 4 Z9 4 U1 0 U2 4 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 2004 VL 16 IS 2 BP 277 EP 288 DI 10.1177/0954008304044106 PG 12 WC Polymer Science SC Polymer Science GA 830UE UT WOS:000222148300010 ER PT J AU Dever, JA McCracken, CA AF Dever, JA McCracken, CA TI Effects of vacuum ultraviolet radiation of various wavelength ranges on Teflon (R) FEP film SO HIGH PERFORMANCE POLYMERS LA English DT Article; Proceedings Paper CT 9th International Symposium on Materials in a Space Environment CY JUN 16-20, 2003 CL NOORDWIJK, NETHERLANDS DE vacuum ultraviolet; space simulation; Teflon (R); degradation ID HUBBLE-SPACE-TELESCOPE AB This paper describes testing to investigate the effects of vacuum ultraviolet (VUV) radiation on Teflon((R)) fluorinated ethylene propylene (FEP) film, examining differences in mechanical properties degradation for samples of 50.8 mum thickness exposed to VUV of various lower cut-off wavelengths. Samples were illuminated in a high vacuum facility by deuterium lamps, which provide radiation in the 115-400 nm wavelength range, but with the highest intensity being below 200 nm. Windows of fused silica, crystalline quartz, and magnesium fluoride provided lower cut-off wavelengths of 155, 140 and 115 nm, respectively. Lamp intensity was measured in the 115-200 nm wavelength range throughout the sample exposures. The determined intensities were used to estimate intensity and incident energy of various wavelength ranges, between 115 and 400 nm. Samples were analysed for tensile strength and elongation at failure. The effects of radiation exposures of different wavelength ranges were compared and discussed in terms of the expected depth to which radiation of various wavelengths is deposited into FEP. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Cleveland State Univ, Cleveland, OH 44115 USA. RP Dever, JA (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd,M-S 309-2, Cleveland, OH 44135 USA. EM joyce.a.dever@nasa.gov NR 9 TC 11 Z9 11 U1 1 U2 8 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 2004 VL 16 IS 2 BP 289 EP 301 DI 10.1177/095400830404044099 PG 13 WC Polymer Science SC Polymer Science GA 830UE UT WOS:000222148300011 ER PT J AU De Groh, KK Banks, BA Dever, JA Hodermarsky, JC AF De Groh, KK Banks, BA Dever, JA Hodermarsky, JC TI Ground-based durability projection of ePTFE on ISS based on Hubble Space Telescope degradation data SO HIGH PERFORMANCE POLYMERS LA English DT Article; Proceedings Paper CT 9th International Symposium on Materials in a Space Environment CY JUN 16-20, 2003 CL NOORDWIJK, NETHERLANDS DE space environment effects; grand based testing; Hubble Space Telescope; International Space Station; Teflon; irradiation; embrittlement; durability projection ID X-RAY PHOTOELECTRON; TEFLON(R) FEP AB Ground-based environmental durability tests have indicated that exposing materials in accelerated tests to environmental model predicted spacecraft mission exposures of known degradation sources does not simulate the extent of damage that occurs in the space environment. One approach to overcoming the difficulties in simulating the space environment using ground-based testing is to calibrate the facility using data from actual space-exposed materials to determine exposure levels required to replicate degraded properties observed in space. This paper describes a ground-to-space correlation method that uses a multiple step process to determine the durability of expanded-polytetrafluoroethylene (ePTFE) for International Space Station (ISS) applications based on ground-based X-ray irradiation and heating exposure that simulates bulk embrittlement as occurs in fluorinated ethylene propylene (FEP) thermal insulation covering the Hubble Space Telescope (HST). This method was designed to damage the back surface of equivalent thickness ePTFE to the same amount of scission damage as occurred in HST FEP (based on elongation data) and then correct for differences in ground test ionizing radiation versus space radiation effects, temperature variations, space ionizing radiation environment variations (spacecraft altitude, inclination and duration), and thickness variations. The analysis indicates that after a 10-year mission, the ISS ePTFE will have an extremely embrittled front surface, with surface cracks induced under any given strain, and a very ductile back surface. This study also found that a thermal induced strain of 0.1 will develop in the ePTFE, and under this strain condition, microscopic cracks will start developing very early in the mission at the exposed surface and develop to a depth of approximately 300 mum after 10 years. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Ohio Aerospace Inst, Cleveland, OH 44142 USA. RP De Groh, KK (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd,M-S 309-2, Cleveland, OH 44135 USA. EM Kim.K.deGroh@nasa.gov NR 20 TC 3 Z9 4 U1 0 U2 3 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 2004 VL 16 IS 2 BP 319 EP 337 DI 10.1177/0954008304044124 PG 19 WC Polymer Science SC Polymer Science GA 830UE UT WOS:000222148300013 ER PT J AU Erev, I Barron, G Remington, R AF Erev, I Barron, G Remington, R TI Right of way in the sky: Two problems in aircraft self-separation and the auction-based solution SO HUMAN FACTORS LA English DT Article ID PEOPLE PLAY GAMES; FORM GAMES; DYNAMICS; MODELS AB There has been a growing movement to give commercial airliners more freedom in choosing their routes and responsibility for detecting and avoiding conflicts. These "free flight" concepts must contain new rules for assigning right of way in potential conflict situations. To evaluate the effect of prospective rules, the current paper derives the expected response of agents who exhibit different levels of sophistication. Traditional game theoretic analysis is used to derive the behavior of rational agents. Computer simulations are used to predict the behavior of boundedly rational reinforcement learners. The results reveal that several seemingly reasonable, straightforward right-of-way rules might lead to undesirable outcomes. These problematic results are robust to the assumed level of rationality. It is shown that these problems can be alleviated by using auctions to resolve competition for right of way. Actual or potential applications of this research include the usage of second price auctions to address right-of-way and similar conflicts. C1 Technion Israel Inst Technol, Fac Ind Engn & Management, IL-32000 Haifa, Israel. Harvard Univ, Sch Business, Boston, MA 02115 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Erev, I (reprint author), Technion Israel Inst Technol, Fac Ind Engn & Management, IL-32000 Haifa, Israel. EM erev@tx.technion.ac.il NR 30 TC 1 Z9 1 U1 0 U2 0 PU HUMAN FACTORS SOC PI SANTA MONICA PA BOX 1369, SANTA MONICA, CA 90406 USA SN 0018-7208 J9 HUM FACTORS JI Hum. Factors PD SUM PY 2004 VL 46 IS 2 BP 267 EP 276 DI 10.1518/hfes.46.2.267.37339 PG 10 WC Behavioral Sciences; Engineering, Industrial; Ergonomics; Psychology, Applied; Psychology SC Behavioral Sciences; Engineering; Psychology GA 844LM UT WOS:000223159700008 PM 15359676 ER PT J AU Korycansky, DG Zahnle, KJ AF Korycansky, DG Zahnle, KJ TI Atmospheric impacts, fragmentation, and small craters on Venus SO ICARUS LA English DT Article DE impacts; craters; Venus ID HIGH-RESOLUTION SIMULATIONS; EARTHS ATMOSPHERE; LARGE METEOROIDS; 3D MODELS; ASTEROIDS; BREAKUP AB We use high-resolution three-dimensional numerical models of aerodynamically disrupted asteroids to predict the characteristic properties of small impact craters on Venus. We map the mass and kinetic energy of the impactor passing though a plane near the surface for each simulation, and find that the typical result is that mass and energy sort themselves into one to several strongly peaked regions, which we interpret as more-or-less discrete fragments. The fragments are sufficiently well separated as to imply the formation of irregular or multiple craters that are quite similar to those found on Venus. We estimate the diameters of the resulting craters using a scaling law derived from the experiments of Schultz and Gault (1985, J. Geophys. Res. 90 (135), 3701-3732) of dispersed impactors into targets. We compare the spacings and sizes of our estimated craters with measured diameters tabulated in a Venus crater database (Herrick and Phillips, 1994a, Icarus 111, 387-416; Herrick et al., 1997, in: Venus II, Univ. of Arizona Press, Tucson, AZ, pp. 1015-1046; Herrick, 2003, http://www.lpi.usra.edu/research/vc/vehoine.htm]) and find quite satisfactory agreement, despite the uncertainty in our crater diameter estimates. The comparison of the observed crater characteristics with the numerical results is an after-the-fact test of our model, namely the fluid-dynainical treatment of large impacts, which the model appears to pass successfully. (C) 2004 Elsevier Inc. All rights reserved. C1 Univ Calif Santa Cruz, Dept Earth Sci, CODEP, Santa Cruz, CA 95064 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Korycansky, DG (reprint author), Univ Calif Santa Cruz, Dept Earth Sci, CODEP, Santa Cruz, CA 95064 USA. EM kory@es.ucsc.edu NR 27 TC 4 Z9 4 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 J9 ICARUS JI Icarus PD JUN PY 2004 VL 169 IS 2 BP 287 EP 299 DI 10.1016/j.icarus.2004.01.010 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823IM UT WOS:000221604300001 ER PT J AU Bishop, JL Murad, E Lane, MD Mancinelli, RL AF Bishop, JL Murad, E Lane, MD Mancinelli, RL TI Multiple techniques for mineral identification on Mars: a study of hydrothermal rocks as potential analogues for astrobiology sites on Mars SO ICARUS LA English DT Review DE spectroscopy; infrared; Raman; Mars; hydrothermal rocks; astrobiology ID INFRARED-EMISSION SPECTROSCOPY; YELLOWSTONE-NATIONAL-PARK; DEPOSITING HOT-SPRINGS; THERMAL EMISSION; MARTIAN SURFACE; REFLECTANCE SPECTROSCOPY; RAMAN-SPECTROSCOPY; MOSSBAUER-SPECTROSCOPY; PARTICULATE SURFACES; SPECTRAL REFLECTANCE AB Spectroscopic studies of Mars analog materials combining multiple spectral ranges and techniques are necessary in order to obtain ground truth information for interpretation of rocks and soils on Mars. Two hydrothermal rocks from Yellowstone National Park, Wyoming, were characterized here because they contain minerals requiring water for formation and they provide a possible niche for some of the earliest organisms on Earth. If related rocks formed in hydrothermal sites on Mars, identification of these would be important for understanding the geology of the planet and potential habitability for life. XRD, thermal properties, VNIR, mid-IR, and Raman spectroscopy were employed to identify the mineralogy of the samples in this study. The rocks studied here include a travertine from Mammoth Formation that contains primarily calcite with some aragonite and gypsum and a siliceous sinter from Octopus Spring that contains a variety of poorly crystalline to amorphous silicate minerals. Calcite was detected readily in the travertine rock using any one of the techniques studied. The small amount of gypsum was uniquely identified using XRD, VNIR, and mid-IR, while the aragonite was uniquely identified using XRD and Raman. The siliceous sinter sample was more difficult to characterize using each of these techniques and a combination of all techniques was more useful than any single technique. Although XRD is the historical standard for mineral identification, it presents some challenges for remote investigations. Thermal properties are most useful for minerals with discrete thermal transitions. Raman spectroscopy is most effective for detecting polarized species such as CO3, OH, and CH, and exhibits sharp bands for most highly crystalline minerals when abundant. Mid-IR spectroscopy is most useful in characterizing Si-O (and metal-O) bonds and also has the advantage that remote information about sample texture (e.g., particle size) can be determined. Mid-IR spectroscopy is also sensitive to structural OH, CO3, and SO4 bonds when abundant. VNIR spectroscopy is best for characterizing metal excitational bands and water, and is also a good technique for identification of structural OH, CO3, SO4, or CH bonds. Combining multiple techniques provides the most comprehensive information about mineralogy because of the different selection rules and particle size sensitivities, in addition to maximum coverage of excitational and vibrational bands at all wavelengths. This study of hydrothermal rocks from Yellowstone provides insights on how to combine information from multiple instruments to identify mineralogy and hence evidence of water on Mars. (C) 2004 Elsevier Inc. All rights reserved. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. Bayer Geol Landesamt, D-95603 Marktredwitz, Germany. Planetary Sci Inst, Tucson, AZ 85705 USA. RP NASA, Ames Res Ctr, SETI Inst, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM jbishop@mail.arc.nasa.gov RI Mancinelli, Rocco/L-8971-2016 NR 105 TC 38 Z9 39 U1 2 U2 22 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD JUN PY 2004 VL 169 IS 2 BP 311 EP 323 DI 10.1016/j.jicarus.2003.12.025 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823IM UT WOS:000221604300003 ER PT J AU Fieseler, PD Adams, OW Vandermey, N Theilig, EE Schimmels, KA Lewis, GD Ardalan, SM Alexander, CJ AF Fieseler, PD Adams, OW Vandermey, N Theilig, EE Schimmels, KA Lewis, GD Ardalan, SM Alexander, CJ TI The Galileo star scanner observations at Amalthea SO ICARUS LA English DT Article DE satellites of Jupiter; planetary rings; Jupiter; impact processes ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; SATELLITES; RINGS AB in November of 2002, the Galileo spacecraft passed within 250 km of Jupiter's moon Amalthea. An onboard telescope, the star scanner, observed a series of bright flashes near the moon. It is believed that these flashes represent sunlight reflected from 7 to 9 small moonlets located within about 3000 km of Amalthea. From star scanner geometry considerations and other arguments, we can constrain the diameter of the observed bodies to be between 0.5 m to several tens of kilometers. In September of 2003, while crossing Amalthea's orbit just prior to Galileo's destruction in the jovian atmosphere, a single additional body seems to have been observed. It is suspected that these bodies are part of a discrete rocky ring embedded within Jupiter's Gossamer ring system. (C) 2004 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Galileo Project, Pasadena, CA 91109 USA. RP Fieseler, PD (reprint author), CALTECH, Jet Prop Lab, Galileo Project, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM paul.d.fieseler@jpl.nasa.gov NR 25 TC 0 Z9 0 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 2004 VL 169 IS 2 BP 390 EP 401 DI 10.1016/j.icarus.2004.01.012 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823IM UT WOS:000221604300009 ER PT J AU Gibbard, SG Macintosh, B Gavel, D Max, CE de Pater, I Roe, HG Ghez, AM Young, EF McKay, CP AF Gibbard, SG Macintosh, B Gavel, D Max, CE de Pater, I Roe, HG Ghez, AM Young, EF McKay, CP TI Speckle imaging of Titan at 2 microns: surface albedo, haze optical depth, and tropospheric clouds 1996-1998 SO ICARUS LA English DT Article DE titan; infrared observations; surfaces; satellite ID ADAPTIVE OPTICS; MULTIPLE-SCATTERING; TRIPLE CORRELATION; GEOMETRIC ALBEDO; ATMOSPHERE; IMAGES; MODEL; HST; BRIGHTNESS; RESOLUTION AB We present results from 14 nights of observations of Titan in 1996-1998 using near-infrared (centered at 2.1 microns) speckle imaging at the 10-meter W.M. Keck Telescope. The observations have a spatial resolution of 0.06 arcseconds. We detect bright clouds on three days in October 1998, with a brightness about 0.5% of the brightness of Titan. Using a 16-stream radiative transfer model (DISORT) to model the central equatorial longitude of each image, we construct a suite of surface albedo models parameterized by the optical depth of Titan's hydrocarbon haze layer. From this we conclude that Titan's equatorial surface albedo has plausible values in the range of 0-0.20. Titan's minimum haze optical depth cannot be constrained from this modeling, but an upper limit of 0.3 at this wavelength range is found. More accurate determination of Titan's surface albedo and haze optical depth, especially at higher latitudes, will-require a model that fully considers the 3-dimensional nature of Titan's atmosphere. (C) 2004 Elsevier Inc. All rights reserved. C1 Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Univ Calif Santa Cruz, Ctr Adapt Opt, Santa Cruz, CA 95064 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Univ Calif Los Angeles, Dept Phys, Los Angeles, CA 90095 USA. SW Res Inst, Boulder, CO 80302 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Gibbard, SG (reprint author), Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. EM sgibbard@igpp.ucllnl.org OI Max, Claire/0000-0003-0682-5436 NR 48 TC 30 Z9 30 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 2004 VL 169 IS 2 BP 429 EP 439 DI 10.1016/j.icarus.2003.12.026 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823IM UT WOS:000221604300012 ER PT J AU Roe, HG de Pater, I McKay, CP AF Roe, HG de Pater, I McKay, CP TI Seasonal variation of Titan's stratospheric ethylene (C2H4) observed SO ICARUS LA English DT Article DE Titan; satellites; atmospheres; infrared observations ID SPECTRAL IRRADIANCE CALIBRATION; HUBBLE-SPACE-TELESCOPE; GENERAL-CIRCULATION; ADAPTIVE OPTICS; ATMOSPHERE; MODEL; PHOTOCHEMISTRY; CLOUDS; HST AB All previous observations of seasonal change on Titan have been of physical phenomena such as clouds and haze. We present here the first observational evidence of chemical change in Titan's atmosphere. Images taken during 1999-2002 (late southern spring on Titan) with the W.M. Keck 110-meter telescope at 8-13 mum show a significant accumulation of ethylene (C2H4) in the south polar stratosphere as well as north-south stratospheric temperature variation (colder at poles). Our observations restrict this newly discovered south polar ethylene accumulation to latitudes south of 60degrees S. The only other observations of the spatial distribution of C2H4 were those of Voyager 1, which found a significant north polar accumulation in early northern spring. We see no build-up in the north, although the highest northern latitudes are obstructed from view in the current season. Our observations constrain any unobserved north polar accumulation of C2H4 to north of 50degrees N latitude. Comparison of the Voyager I results with our new results show seasonal chemical change has occurred in Titan's atmosphere. (C) 2004 Elsevier Inc. All rights reserved. C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Roe, HG (reprint author), CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. EM hroe@gps.caltech.edu NR 34 TC 37 Z9 37 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 2004 VL 169 IS 2 BP 440 EP 461 DI 10.1016/j.icarus.2004.01.002 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823IM UT WOS:000221604300013 ER PT J AU Dobrovolskis, AR Lissauer, JJ AF Dobrovolskis, AR Lissauer, JJ TI The fate of ejecta from Hyperion SO ICARUS LA English DT Article DE celestial mechanics; cratering; satellites of Saturn ID CHAOTIC ROTATION; GEOLOGICAL HISTORIES; VOYAGER OBSERVATIONS; SNC METEORITES; IMPACT EJECTA; SATURN SYSTEM; IAPETUS; ORIGIN; PHOEBE; TITAN AB Ejecta from Saturn's moon Hyperion are subject to powerful perturbations from nearby Titan, which control their ultimate fate. We have performed numerical integrations to simulate a simplified system consisting of Saturn (including optical flattening as well as dynamical oblateness), its main ring system (treated as a massless flat annulus), the moons Tethys, Dione, Titan, Hyperion, and Iapetus, and the Sun (treated simply as a massive satellite). At several different points in Hyperion's orbit, 1050 massless particles, more or less evenly distributed over latitude and longitude, were ejected radially outward from 1 km above Hyperion's mean radius at speeds 10% faster than escape speed from Hyperion. Most of these particles were removed within the first few thousand years, but similar to3% of them survived the entire 100,000-year duration of the simulations. Ejecta from Hyperion are much more widely scattered than previously thought, and can cross the orbits of all of Saturn's satellites. About 9% of all the particles escaped from the saturnian system, but Titan accreted similar to78% of the total, while Hyperion reaccreted only similar to5%. This low efficiency of reaccretion may help to account for Hyperion's small size and rugged shape. Only similar to1% of all the particles hit other satellites, and another similar to1% impacted Saturn itself, while similar to3% of them struck its main rings. The high proportion of impacts into Saturn's rings is surprising; these collisions show a broad decline in impact speed with time, suggesting that Hyperion ejecta gradually spread inwards. Additional simulations were used to investigate the dependence of ejecta evolution on launch speed, the mass of Hyperion, and the presence of the Sun. In general, the wide distribution of ejecta from Hyperion suggests that it does contribute to "Population II" craters on the inner satellites of Saturn. Ejecta which escape from a satellite into temporary orbit about its planet, but later reimpact into the same moon or another one produce "poltorary" impacts, intermediate in character between primary and secondary impacts. It may be possible to distinguish poltorary craters from primary and secondary craters on the basis of morphology. (C) 2004 Elsevier Inc. All rights reserved. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. RP Dobrovolskis, AR (reprint author), NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. EM dobro@cosmic.arc.nasa.gov NR 67 TC 19 Z9 19 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 EI 1090-2643 J9 ICARUS JI Icarus PD JUN PY 2004 VL 169 IS 2 BP 462 EP 473 DI 10.1016/j.icarus.2004.01.006 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823IM UT WOS:000221604300014 ER PT J AU Pesnell, WD Grebowsky, JM Weisman, AL AF Pesnell, WD Grebowsky, JM Weisman, AL TI Watching meteors on Triton SO ICARUS LA English DT Article DE meteoroids; atmosphere; composition; ionosphere ID MARTIAN ATMOSPHERE; TITANS ATMOSPHERE; IONOSPHERE; NEPTUNE; PHOTOCHEMISTRY; ABLATION; MODEL; IONS AB The thin atmosphere of Neptune's moon Triton is dense enough to ablate micrometeoroids as they pass through. A combination of Triton's orbital velocity around Neptune and its orbital velocity around the Sun gives a maximum meteoroid impact velocity of approximately 19 km s(-1), sufficient to heat the micrometeoroids to visibility as they enter. The ablation profiles of icy and stony micrometeoroids were calculated, along with the estimated brightness of the meteors. In contrast to the terrestrial case, visible meteors would extend very close to the surface of Triton. In addition, the variation in the meteoroid impact velocity as Triton orbits Neptune produces a large variation in the brightness of meteors with orbital phase, a unique Solar System phenomenon. (C) 2004 Elsevier Inc. All rights reserved. C1 Nomad Res Inc, Arnold, MD 21012 USA. NASA, Goddard Space Flight Ctr, Planetary Magnetospheres Branch, Greenbelt, MD 20771 USA. River Hill High Sch, Clarkesville, MD 21029 USA. RP Pesnell, WD (reprint author), Nomad Res Inc, 795 Scarborough Court, Arnold, MD 21012 USA. EM pesnell@nomadresearch.com RI Pesnell, William/D-1062-2012; Grebowsky, Joseph/I-7185-2013; Weisman, Andrew/O-3986-2014 OI Pesnell, William/0000-0002-8306-2500; Weisman, Andrew/0000-0002-1169-0540 NR 32 TC 3 Z9 3 U1 1 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 J9 ICARUS JI Icarus PD JUN PY 2004 VL 169 IS 2 BP 482 EP 491 DI 10.1016/j.icarus.2004.01.011 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823IM UT WOS:000221604300016 ER PT J AU Park, W Sturdevant, M Orsi, J Wertheimer, A Fergusson, E Heard, W Shirley, T AF Park, W Sturdevant, M Orsi, J Wertheimer, A Fergusson, E Heard, W Shirley, T TI Interannual abundance patterns of copepods during an ENSO event in Icy Strait, southeastern Alaska SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Zooplankton Production Symposium CY MAY 20-23, 2003 CL Gijon, SPAIN DE a regional cold event; El Nino; ENSO; interannual density variation; large copepods; small copepods ID JUVENILE PACIFIC SALMON; SUB-ARCTIC PACIFIC; PRINCE-WILLIAM-SOUND; NORTHERN BRITISH-COLUMBIA; 1997-1998 EL-NINO; CALIFORNIA CURRENT; LARVAL FISH; BERING SEA; ZOOPLANKTON COMMUNITIES; ONCORHYNCHUS-GORBUSCHA AB Interannual copepod abundance (number m(-3)) and sea surface temperatures (SST, 2-m depth) were examined from four stations in Icy Strait, southeastern Alaska, monthly from May to September, 1997-2002. SST was generally lowest in May (congruent to7degreesC), increased rapidly to a summer peak (congruent to12degreesC), and declined again by September. SST was relatively high in the El Nino year, 1998, and was low during a regional cold event, 2002, compared to other years. Overall, copepods constituted 18.8% of the total biomass and 88.2% of zooplankton abundance, and included >34 species. The common copepod species were grouped into two size classes by total length (TL), those >2.5 nun (11.4% biomass, 24.2% abundance) and those <2.5 mm (7.4% biomass, 64.0% abundance). In order of dominance, large species included Metridia ochoiensis, Calanus marshallae, M. pacificus, and Neocalanus spp. and small species included Pseudocalanus spp., Acartia longiremis, and Centropages abdominalis. Overall, the small species were more abundant than the large species. Densities of large copepods were relatively low compared to those of small copepods during El Nino (1998) and a cold year (2002), suggesting that large copepods with long lifespans are more sensitive to ocean climate fluctuation. (C) 2004 International Council for the Exploration of the Sea. Published by Elsevier Ltd. All rights reserved. C1 Univ Alaska, Juneau Ctr, Sch Fisheries & Ocean Sci, Juneau, AK 99801 USA. NOAA, Alaska Fisheries Sci Ctr, Auke Bay Lab, Natl Marine Fisheries Serv, Juneau, AK 99801 USA. RP Park, W (reprint author), Univ Alaska, Juneau Ctr, Sch Fisheries & Ocean Sci, 11120 Glacier Highway, Juneau, AK 99801 USA. EM w.park@uqf.edu NR 81 TC 17 Z9 18 U1 0 U2 2 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD JUN PY 2004 VL 61 IS 4 BP 464 EP 477 DI 10.1016/j.icesjms.2004.03.017 PG 14 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 833FS UT WOS:000222322500004 ER PT J AU Heebner, JE Wong, V Schweinsberg, A Boyd, RW Jackson, DJ AF Heebner, JE Wong, V Schweinsberg, A Boyd, RW Jackson, DJ TI Optical transmission characteristics of fiber ring resonators SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE delay effects; interferometry; optical fiber coupling; optical fiber delay lines; resonators ID MICRORING RESONATORS; FILTERS AB We present the results of an experimental investigation of the transfer characteristics of a fiber ring resonator for various values of the resonator finesse. In particular, we measure the spectral dependence of the intensity transmission and the induced phase shift in the undercoupled, critically coupled, and over-coupled regimes. We also demonstrate tunable optical (true time) group delay via a fiber ring resonator and show that a high finesse is unnecessary. Our laboratory results are in excellent agreement with theoretical predictions. C1 Univ Rochester, Inst Opt, Rochester, NY 14627 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Heebner, JE (reprint author), Univ Rochester, Inst Opt, 601 Elmwood Ave, Rochester, NY 14627 USA. RI Heebner, John/C-2411-2009; Schweinsberg, Aaron/D-7488-2012 NR 17 TC 119 Z9 124 U1 2 U2 22 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD JUN PY 2004 VL 40 IS 6 BP 726 EP 730 DI 10.1109/JQE.2004.828232 PG 5 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 826VO UT WOS:000221857800015 ER PT J AU Maestrini, A Ward, J Gill, J Javadi, H Schlecht, E Chattopadhyay, G Maiwald, F Erickson, NR Mehdi I AF Maestrini, A Ward, J Gill, J Javadi, H Schlecht, E Chattopadhyay, G Maiwald, F Erickson, NR Mehdi, I TI A 1.7-1.9 THz local oscillator source SO IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS LA English DT Article DE frequency multiplier; local oscillator; Schottky diode; THz technology; varactor AB We report on the design and performance of a x 2 x 3 x 3 frequency multiplier chain to the 1.7-1.9 THz band. GaAs-based planar Schottky diodes are utilized in each stage. A W-band power amplifier, driven by a commercially available synthesizer, was used to pump the chain with 100 mW of input power. The peak measured output power at room temperature is 3 muW at 1740 GHz. When cooled to 120 K, the chain provides more than 1.5 muW from 1730 to 1875 GHz and produced a peak of 15 muW at 1746 GHz. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA. RP Maestrini, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 62 Z9 66 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1531-1309 J9 IEEE MICROW WIREL CO JI IEEE Microw. Wirel. Compon. Lett. PD JUN PY 2004 VL 14 IS 6 BP 253 EP 255 DI 10.1109/LMWC.2004.828027 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 829PM UT WOS:000222062100001 ER PT J AU Ryan, MA Zhou, HY Buehler, MG Manatt, KS Mowrey, VS Jackson, SR Kisor, AK Shevade, AV Homer, ML AF Ryan, MA Zhou, HY Buehler, MG Manatt, KS Mowrey, VS Jackson, SR Kisor, AK Shevade, AV Homer, ML TI Monitoring space shuttle air quality using the jet propulsion laboratory electronic nose SO IEEE SENSORS JOURNAL LA English DT Article DE air quality; carbon black; electronic nose (ENose); polymer sensor; polymer composite ID CONDUCTING POLYMER; COMPOSITE; ENVIRONMENT AB A miniature electronic nose (ENose) has been designed and built at the Jet Propulsion Laboratory (JPL), Pasadena, CA, and was designed to detect, identify, and quantify ten common contaminants and relative humidity changes. The sensing array includes 32 sensing films made from polymer carbon-black composites. Event identification and quantification were done using the Levenberg-Marquart nonlinear least squares method. After successful ground training, this ENose was used in a demonstration experiment aboard STS-95 (October-November, 1998), in which the ENose was operated continuously for six days and recorded the sensors' response to the air in the mid-deck. Air samples were collected daily and analyzed. independently after the flight. Changes in shuttle-cabin humidity were detected and quantified by the JPL ENose; neither the ENose nor the air samples detected any of the contaminants on the target list. The device is microgravity insensitive. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ryan, MA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Margaret.A.Ryan@jpl.nasa.gov; Hanying.Zhou@jpl.nasa.gov; martin.g.buehler@jpl.nasa.gov; kmanatt@jpl.nasa.gov; victoria.s.mowrey@jpl.nasa.gov; Shannon.P.Jackson@jpl.nasa.gov; ADAM.KISOR@jpl.nasa.gov; Abhijit.Shevade@jpl.nasa.gov; Margie.L.Homer@jpl.nasa.gov NR 19 TC 61 Z9 64 U1 0 U2 20 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1530-437X J9 IEEE SENS J JI IEEE Sens. J. PD JUN PY 2004 VL 4 IS 3 BP 337 EP 347 DI 10.1109/JSEN.2004.827275 PG 11 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Applied SC Engineering; Instruments & Instrumentation; Physics GA 818HZ UT WOS:000221237500010 PM 15875356 ER PT J AU Kamiya, K Warner, BA Numazawa, T AF Kamiya, K Warner, BA Numazawa, T TI Geometry dependence of superconducting shielding for sensitive detectors SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 18th International Conference on Magnet Technology CY OCT 20-24, 2003 CL Morioka City, JAPAN SP IEEE, Natl Inst Mat Sci, Iwate Prefecture, Morioka City, Cryogen Assoc Japan, IEE Japan, Coca Cola Co, Fuji Xerox Co Ltd, Nippon Telegraph & Telephone E Corp, SEIKO EPSON CORP DE Meissner effect; superconducting shield AB Superconducting shielding is a powerful technique for shielding detectors. However, it is sensitive to details of geometry. This paper uses the geometry of the shielding of the Submillimeter and Far Infrared Experiment (SAFIRE) as a basis for study. Shielding tests are performed on three different geometries of niobium-disk, ring and tube. Attempts to model the superconducting shielding are also made and compared with measurements. C1 Natl Inst Mat Sci, Tsukuba Magnet Lab, Tsukuba, Ibaraki 3050053, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20740 USA. RP Kamiya, K (reprint author), Natl Inst Mat Sci, Tsukuba Magnet Lab, Tsukuba, Ibaraki 3050053, Japan. EM kamiya.koji@nims.go.jp; Brent.A.Warner@nasa.gov NR 9 TC 3 Z9 3 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 2004 VL 14 IS 2 SI SI BP 1042 EP 1045 DI 10.1109/TASC.2004.830389 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 844HA UT WOS:000223147500218 ER PT J AU Li, L Im, E Connor, LN Chang, PS AF Li, L Im, E Connor, LN Chang, PS TI Retrieving ocean surface wind speed from the TRMM precipitation radar measurements SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE microwave remote sensing; ocean surface wind; precipitation radar (PR); Tropical Rainfall Measuring Mission (TRMM) ID MEASURING MISSION TRMM; SCATTEROMETER WINDS; MICROWAVE IMAGER; MODEL FUNCTION; CROSS-SECTION; SATELLITE; ALGORITHM; GHZ AB Space borne scatterometery has been used for many years now to retrieve the ocean surface wind field from normalized radar cross-section measurements of the ocean surface. Though designed specifically for the measurement of precipitation profiles in the atmosphere, the Precipitation Radar (PR) of the Tropical Rainfall Measuring Mission (TRMM) also acquires surface backscattering measurements of the global oceans. As such, this instrument provides an interesting opportunity to explore the benefits and pitfalls of alternative radar configurations in the satellite remote sensing of ocean winds. In this paper, a technique was developed for retrieving ocean surface winds using surface backscattering measurements from the TRMM PR. The wind retrieval algorithm developed for TRMM PR makes use of a maximum-likelihood estimation technique to compensate for the low backscattering associated with the PR configuration. The high vertical resolution of the PR serves to filter-out rain-contaminated cells normally integrated into Ku-band scatterometer measurements. The algorithm was validated through comparisons of ocean surface wind speeds derived from PR with remotely measured winds from TMI and QuikSCAT, as well as in situ observations from oceanographic buoys, revealing good agreements in wind speed estimations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Natl Ocean & Atmospher Adm, Camp Springs, MD 20746 USA. RP Li, L (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM li.li@jpl.nasa.gov; eastwood.im@jpl.nasa.gov; Laurence.connor@noaa.gov; paul.s.chang@noaa.gov RI Chang, Paul/F-5580-2010; Connor, Laurence/E-7930-2011 OI Chang, Paul/0000-0001-5113-0938; Connor, Laurence/0000-0002-5276-6257 NR 28 TC 26 Z9 27 U1 0 U2 3 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 JUN PY 2004 VL 42 IS 6 BP 1271 EP 1282 DI 10.1109/TGRS.2004.828924 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 830NT UT WOS:000222129900016 ER PT J AU Li, RR Kaufman, YJ Hao, WM Salmon, JM Gao, BC AF Li, RR Kaufman, YJ Hao, WM Salmon, JM Gao, BC TI A technique for detecting burn scars using MODIS data SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE burn scars; fires; Moderate Resolution Imaging Spectroradiometer (MODIS); remote sensing ID BOREAL FOREST-FIRES; RESOLUTION; ALGORITHM; IDENTIFICATION; TROPICS; SURFACE; SYSTEM; CLOUD AB The Moderate Resolution Imaging Spectroradiometer (MODIS) instruments onboard the National Aeronautics and Space Administration Terra and Aqua spacecrafts have several visible and near-infrared (NIR) channels with resolutions of 250, 500, and 1 km for remote sensing of land surfaces and atmosphere. The MODIS data directly broadcasted to ground receiving stations can have many practical applications, including the rapid assessment of fires and burned areas. In this paper, we describe an empirical technique for remote sensing of burn scars using a single dataset of MODIS NIR channels centered near 1.24 and 2.13 mum. These channels are sensitive to changes in the surface properties induced by the fire and are not obscured by smoke. Therefore, they allow remote sensing of burn scars in the presence of smoke. Detection of burn scars from single MODIS images, without the need of data from previous days, is very useful for near real-time burn scar recognition in operational direct broadcasting systems. The technique is applied to MODIS data acquired over the western U.S. during the summer fire season, the southeastern part of Canada during the summer and spring seasons, and the southeastern part of Australia. The burnt areas estimated from MODIS data are consistent with those estimated from the high spatial resolution Landsat 7 imaging data. C1 Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Forest Serv, Rocky Mt Res Stn, Fire Sci Lab, USDA, Missoula, MT 59807 USA. USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. RP Li, RR (reprint author), Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. EM lirongr@climate.gsfc.nasa.gov NR 33 TC 36 Z9 39 U1 3 U2 15 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 JUN PY 2004 VL 42 IS 6 BP 1300 EP 1308 DI 10.1109/TGRS.2004.826801 PG 9 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 830NT UT WOS:000222129900019 ER PT J AU Hodel, AS Hall, CE AF Hodel, AS Hall, CE TI Comments on "variable-structure PID control to prevent integrator windup" - Reply SO IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS LA English DT Article DE control systems; design methodology C1 Auburn Univ, Dept Elect & Comp Engn, Auburn, AL 36849 USA. NASA, George C Marshall Space Flight Ctr, Control Syst Grp, Huntsville, AL 35812 USA. RP Hodel, AS (reprint author), Auburn Univ, Dept Elect & Comp Engn, Auburn, AL 36849 USA. EM a.s.hodel@eng.auburn.edu NR 3 TC 4 Z9 4 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0278-0046 J9 IEEE T IND ELECTRON JI IEEE Trans. Ind. Electron. PD JUN PY 2004 VL 51 IS 3 BP 738 EP 739 DI 10.1109/TIE.2004.827822 PG 2 WC Automation & Control Systems; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA 825RA UT WOS:000221774700027 ER PT J AU Kedem, B Wolff, DB Fokianos, K AF Kedem, B Wolff, DB Fokianos, K TI Statistical Comparison of algorithms SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE C-band radar; empirical likelihood; exponential tilt; reference distribution; S-band radar; tropical rainfall measuring mission AB A "reference" algorithm or instrument and its various "distortions" are considered, where the distortions carry some valid information about the reference. The objective is to combine data from the reference and the distortions together in some manner in order to extract information from both the reference, as well as the distortions, and produce improved inference about the true reference algorithm. This is illustrated in terms of m precipitation radars and semiparametric estimation of the reference distribution and the distortion parameters. C1 Univ Maryland, Dept Math, College Pk, MD 20742 USA. Univ Maryland, Syst Res Inst, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. Univ Cypru, Dept Math & Stat, CY-1678 Nikosia, Cyprus. RP Kedem, B (reprint author), Univ Maryland, Dept Math, College Pk, MD 20742 USA. OI Fokianos, Konstantinos/0000-0002-0051-711X NR 9 TC 7 Z9 8 U1 0 U2 1 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 2004 VL 53 IS 3 BP 770 EP 776 DI 10.1109/TIM.2004.827301 PG 7 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 822YZ UT WOS:000221578200021 ER PT J AU Ngo, Q Petranovic, D Krishnan, S Cassell, AM Ye, Q Li, J Meyyappan, M Yang, CY AF Ngo, Q Petranovic, D Krishnan, S Cassell, AM Ye, Q Li, J Meyyappan, M Yang, CY TI Electron transport through metal-multiwall carbon nanotube interfaces SO IEEE TRANSACTIONS ON NANOTECHNOLOGY LA English DT Article DE carbon nanotube (CNT); contact resistance; on-chip interconnect ID CHEMICAL-VAPOR-DEPOSITION; CONTACT RESISTANCE; FORMULA; GROWTH AB In this paper, we examine mechanisms of electron transport across the metal-carbon nanotube (CNT) interface for two different types of multiwall carbon nanotube (MWNT) architectures, horizontal or side-contacted MWNTs and vertical or end-contacted MWNTs. Horizontally aligned nanotube growth and electrical characteristics are examined with respect to their potential applications in silicon-based technologies. Recent advances in the synthesis techniques of vertical MWNTs have also enhanced the possibility for a manufacturable solution incorporating this novel material as on-chip interconnects or vias as copper interconnect feature sizes are scaled into the sub-100-nm regime. A vertical MWNT architecture is presented that may be suitable for integration into silicon-based technologies. The growth method for this architecture and its effect on electrical characteristics are examined. Through simulations, dc measurements, and comparison of our results with previous studies, we explain why high contact resistance is observed in metal-CNT-metal systems. C1 Santa Clara Univ, Ctr Nanostruct, Santa Clara, CA 95050 USA. NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Ngo, Q (reprint author), Santa Clara Univ, Ctr Nanostruct, Santa Clara, CA 95050 USA. EM gngo1@scu.edu RI Li, Jun/H-7771-2013 OI Li, Jun/0000-0002-3689-8946 NR 29 TC 67 Z9 70 U1 0 U2 20 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1536-125X J9 IEEE T NANOTECHNOL JI IEEE Trans. Nanotechnol. PD JUN PY 2004 VL 3 IS 2 BP 311 EP 317 DI 10.1109/tnano.2004.828553 PG 7 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Science & Technology - Other Topics; Materials Science; Physics GA 827KZ UT WOS:000221899800015 ER PT J AU Bongi, M Adriani, O Ambriola, A Bakaldin, A Barbarino, GC Basili, A Bazilevskaja, G Bellotti, R Bencardino, R Boezio, M Bogomolov, EA Bonechi, L Bongiorno, L Bonvicini, V Boscherini, M Cafagna, FS Campana, D Carlson, P Casolino, M Castellini, G Circella, M De Marzo, CN De Pascale, MP Furano, G Galper, AM Giglietto, N Grigorjeva, A Koldashov, SV Korotkov, MG Krut'kov, SY Lund, J Lundquist, J Menicucci, A Menn, W Mikhailov, VV Minori, M Mirizzi, N Mitchell, JW Mocchiutti, E Morselli, A Mukhametshin, R Orsi, S Osteria, G Papini, P Pearce, M Picozza, P Ricci, M Ricciarini, SB Romita, M Rossi, G Russo, S Schiavon, P Simon, M Sparvoli, R Spillantini, P Spinelli, P Stochaj, SJ Stozhkov, Y Straulino, S Streitmatter, RE Taccetti, F Vacchi, A Vannuccini, E Vasilyev, GI Voronov, SA Wischnewski, R Yurkin, Y Zampa, G Zampa, N AF Bongi, M Adriani, O Ambriola, A Bakaldin, A Barbarino, GC Basili, A Bazilevskaja, G Bellotti, R Bencardino, R Boezio, M Bogomolov, EA Bonechi, L Bongiorno, L Bonvicini, V Boscherini, M Cafagna, FS Campana, D Carlson, P Casolino, M Castellini, G Circella, M De Marzo, CN De Pascale, MP Furano, G Galper, AM Giglietto, N Grigorjeva, A Koldashov, SV Korotkov, MG Krut'kov, SY Lund, J Lundquist, J Menicucci, A Menn, W Mikhailov, VV Minori, M Mirizzi, N Mitchell, JW Mocchiutti, E Morselli, A Mukhametshin, R Orsi, S Osteria, G Papini, P Pearce, M Picozza, P Ricci, M Ricciarini, SB Romita, M Rossi, G Russo, S Schiavon, P Simon, M Sparvoli, R Spillantini, P Spinelli, P Stochaj, SJ Stozhkov, Y Straulino, S Streitmatter, RE Taccetti, F Vacchi, A Vannuccini, E Vasilyev, GI Voronov, SA Wischnewski, R Yurkin, Y Zampa, G Zampa, N TI PAMELA: A satellite experiment for antiparticles measurement in cosmic rays SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT IEEE-Nuclear-Science Symposium/Medical Imaging Conference CY OCT 19-25, 2003 CL Portland, OR SP IEEE DE antimatter; cosmic rays; satellite experiment ID SOLAR MINIMUM ACTIVITY; ANTIPROTON FLUX; IMAGING CALORIMETER; ELECTRONS; POSITRONS; SPECTRA; RADIATION; RATIO AB PAMELA is a satellite-borne experiment that will study the antiproton and positron fluxes in cosmic rays in a wide range of energy (from 80 MeV up to 190 GeV for antiprotons and from 50 MeV up to 270 GeV for positrons) and with high statistics, and that will measure the antihelium/helium ratio with a sensitivity of the order of 10(-8). The detector will fly on-board a polar orbiting Resurs DK1 satellite, which will be launched into space by a Soyuz rocket in 2004 from Baikonur cosmodrome in Kazakhstan, for a 3-year-long mission. Particle identification and energy measurements are performed in the PAMELA apparatus using the following subdetectors: a magnetic spectrometer made up of a permanent magnet equipped with double-sided microstrip silicon detectors, an electromagnetic imaging calorimeter composed of layers of tungsten absorber and silicon detectors planes, a transition radiation detector made of straw tubes interleaved with carbon fiber radiators, a plastic scintillator time-of-flight and trigger system, a set of anticounter plastic scintillator detectors, and a neutron detector. The features of the detectors and the main results obtained in beam test sessions are presented. C1 Univ Florence, I-50019 Sesto Fiorentino, Italy. Ist Nazl Fis Nucl, I-50019 Sesto Fiorentino, Italy. Univ Bari, I-70426 Bari, Italy. Ist Nazl Fis Nucl, I-70426 Bari, Italy. Moscow Engn & Phys Inst, Moscow 115409, Russia. Univ Naples Federico 2, Dipartimento Sci Fis, I-80126 Naples, Italy. Ist Nazl Fis Nucl, I-80126 Naples, Italy. Univ Roma Tor Vergata, I-00133 Rome, Italy. Ist Nazl Fis Nucl, I-00133 Rome, Italy. PN Lebedev Phys Inst, Moscow 119991, Russia. Univ Trieste, I-34127 Trieste, Italy. Ist Nazl Fis Nucl, I-34127 Trieste, Italy. AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. Univ Siegen, FB Phys, D-57068 Siegen, Germany. Royal Inst Technol, S-10691 Stockholm, Sweden. CNR, Ist Fis Applicata N Carrara, I-50127 Florence, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. New Mexico State Univ, Particle Astrophys Lab, Las Cruces, NM 88003 USA. RP Bongi, M (reprint author), Univ Florence, I-50019 Sesto Fiorentino, Italy. EM bongi@fi.infn.it RI Morselli, Aldo/G-6769-2011; Bongi, Massimo/L-9417-2015; Galper, Arkady/M-9610-2015; Voronov, Sergey/P-9654-2016; giglietto, nicola/I-8951-2012; Cafagna, Francesco/A-9299-2010; Mocchiutti, Emiliano/I-8049-2013; Mikhailov, Vladimir/B-5368-2014; Vasilyev, Gennady/E-4843-2014; Vacchi, Andrea/C-1291-2010; Krutkov, Sergey/E-7561-2014; Barbarino, Giancarlo/L-2559-2015; OI Morselli, Aldo/0000-0002-7704-9553; Bongi, Massimo/0000-0002-6050-1937; Voronov, Sergey/0000-0002-9209-0618; giglietto, nicola/0000-0002-9021-2888; Cafagna, Francesco/0000-0002-7450-4784; Mocchiutti, Emiliano/0000-0001-7856-551X; Mikhailov, Vladimir/0000-0003-3851-2901; Vacchi, Andrea/0000-0003-3855-5856; Barbarino, Giancarlo/0000-0001-9253-3397; Papini, Paolo/0000-0003-4718-2895; Boezio, Mirko/0000-0002-8015-2981; Taccetti, Francesco/0000-0003-2657-2990; Bellotti, Roberto/0000-0003-3198-2708; casolino, marco/0000-0001-6067-5104; Ricciarini, Sergio Bruno/0000-0001-6176-3368; SPINELLI, Paolo/0000-0001-6688-8864; Castellini, Guido/0000-0002-0177-0643; Sparvoli, Roberta/0000-0002-6314-6117; Picozza, Piergiorgio/0000-0002-7986-3321 NR 32 TC 7 Z9 7 U1 2 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 2004 VL 51 IS 3 BP 854 EP 859 DI 10.1109/TNS.2004.829504 PN 3 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 837OI UT WOS:000222644400010 ER PT J AU Bhattacharjee, S Booske, JH Kory, CL van der Weide, DW Limbach, S Gallagher, S Welter, JD Lopez, MR Gilgenbach, RM Ives, RL Read, ME Divan, R Mancini, DC AF Bhattacharjee, S Booske, JH Kory, CL van der Weide, DW Limbach, S Gallagher, S Welter, JD Lopez, MR Gilgenbach, RM Ives, RL Read, ME Divan, R Mancini, DC TI Folded waveguide traveling-wave tube sources for Terahertz radiation SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE delayed feedback oscillator; folded waveguide (FWG) traveling-wave tube (TWT); frequency spectrum; high power; microfabrication; phase; Terahertz radiation; wide-band ID DEVICES AB Microfabricated folded waveguide traveling-wave tubes (TWTs) are potential compact sources of wide-band, high-power terahertz radiation. We present feasibility studies of an oscillator concept using an amplifier with delayed feedback. Simulations of a 560-GHz oscillator and experimental evaluation of the concept at 50 GHz are presented. Additionally, results from various fabrication methods that are under investigation, such as X-ray lithography, electroforming, and molding (LIGA), UV LIGA, and deep reactive ion etching are presented. Observations and measurements are reported on the generation of stable single-frequency oscillation states. On varying the feedback level the oscillation changes from a stable single-frequency state at the threshold to multifrequency spectra in the overdriven state. Simulation and experimental results on amplifier characterization and dynamics of the regenerative TWT oscillator include spectral evolution and phase stability of the generated frequencies. The results of the experiment are in good agreement with the simulations. C1 Univ Wisconsin, Dept Elect & Comp Engn, Madison, WI 53706 USA. NASA, Glenn Res Ctr, Analex Corp, Cleveland, OH 44135 USA. Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48105 USA. Calabazas Creek Res Inc, Saratoga, CA 95070 USA. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Bhattacharjee, S (reprint author), Univ Wisconsin, Dept Elect & Comp Engn, Madison, WI 53706 USA. EM sudeepb@ece.wise.edu RI Bhattacharjee, Sudeep/C-7085-2014 OI Bhattacharjee, Sudeep/0000-0002-5369-9818 NR 32 TC 132 Z9 146 U1 3 U2 29 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 2004 VL 32 IS 3 BP 1002 EP 1014 DI 10.1109/TPS.2004.828886 PN 1 PG 13 WC Physics, Fluids & Plasmas SC Physics GA 844UR UT WOS:000223186600022 ER PT J AU Kuhn, DR Wallace, DR Gallo, AM AF Kuhn, DR Wallace, DR Gallo, AM TI Software fault interactions and implications for software testing SO IEEE TRANSACTIONS ON SOFTWARE ENGINEERING LA English DT Article DE statistical methods; testing strategies; test design ID COMBINATORIAL DESIGN; TEST-GENERATION AB Exhaustive testing of computer software is intractable, but empirical studies of software failures suggest that testing can in some cases be effectively exhaustive. Data reported in this study and others show that software failures in a variety of domains were caused by combinations of relatively few conditions. These results have important implications for testing. If all faults in a system can be triggered by a combination of n or fewer parameters, then testing all n-tuples of parameters is effectively equivalent to exhaustive testing, if software behavior is not dependent on complex event sequences and variables have a small set of discrete values. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM kuhn@nist.gov; dwallac@pop300.gsfc.nasa.gov; al.gallo@nasa.gov NR 21 TC 208 Z9 221 U1 0 U2 6 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0098-5589 EI 1939-3520 J9 IEEE T SOFTWARE ENG JI IEEE Trans. Softw. Eng. PD JUN PY 2004 VL 30 IS 6 BP 418 EP 421 DI 10.1109/TSE.2004.24 PG 4 WC Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 820IW UT WOS:000221383400006 ER PT J AU Ruan, S Tu, F Pattipati, KR Patterson-Hine, A AF Ruan, S Tu, F Pattipati, KR Patterson-Hine, A TI On a multimode test sequencing problem SO IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART B-CYBERNETICS LA English DT Article DE AND/OR graph search; AO*; entropy; huffman coding; information heuristic; rollout algorithm; sequential fault diagnosis; test sequencing problem ID SEQUENTIAL FAULT-DIAGNOSIS; HEURISTIC-SEARCH; INFORMATION-THEORY; ALGORITHMS AB Test sequencing is a binary identification problem wherein one needs to develop a minimal expected cost test procedure to determine which one of a finite number of possible failure states, if any, is present. In this paper, we consider a multimode test sequencing (MMTS) problem, in which tests are distributed among multiple modes and additional transition costs will be incurred if a test sequence involves mode changes. The multimode test sequencing problem can be solved optimally via dynamic programming or AND/OR graph search methods. However, for large systems, the associated computation with dynamic programming or AND/OR graph search methods is substantial due to the rapidly increasing number of OR nodes (denoting ambiguity states and current modes) and AND nodes (denoting next modes and tests) in the search graph. In order to overcome the computational explosion, we propose to apply three heuristic algorithms based on information gain: information gain heuristic (IG), mode capability evaluation (MC), and mode capability evaluation With limited exploration of depth and degree of mode Isolation (MCLEI). We also propose to apply rollout strategies, which are guaranteed to improve the performance of heuristics, as long as the heuristics are sequentially improving. We show computational results, which suggest that the information-heuristic based rollout policies are significantly better than traditional information gain heuristic. We also show that among the three information heuristics proposed, MCLEI achieves the best tradeoff between optimality and computational complexity. C1 Univ Connecticut, Elect & Comp Engn Dept, Storrs, CT 06269 USA. Qualtech Syst Inc, Wethersfield, CT 06109 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Ruan, S (reprint author), Univ Connecticut, Elect & Comp Engn Dept, Storrs, CT 06269 USA. EM sruan@engr.uconn.edu; tufang@engr.uconn.edu; krishna@engr.uconn.edu; apatterson-hine@mail.arc.nasa.gov NR 20 TC 11 Z9 21 U1 1 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1083-4419 J9 IEEE T SYST MAN CY B JI IEEE Trans. Syst. Man Cybern. Part B-Cybern. PD JUN PY 2004 VL 34 IS 3 BP 1490 EP 1499 DI 10.1109/TSMCB.2004.825940 PG 10 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Computer Science, Cybernetics SC Automation & Control Systems; Computer Science GA 822YY UT WOS:000221578100015 PM 15484919 ER PT J AU Badescu, M Mavroidis, C AF Badescu, M Mavroidis, C TI New performance indices and workspace analysis of reconfigurable hyper-redundant robotic arms SO INTERNATIONAL JOURNAL OF ROBOTICS RESEARCH LA English DT Article DE reconfigurable robots; parallel platforms; workspace analysis ID SELF-RECONFIGURATION; SYSTEM; MANIPULATOR; CAPABILITIES; GENERATION; MECHANISMS; KINEMATICS; DESIGN AB In this paper, we introduce new performance indices to characterize the workspace of reconfigurable hyper-redundant robotic arms. These indices are then used to analyze the workspace of a type of hyper-redundant robotic arm using as modules lower mobility parallel platforms. The modules of the reconfigurable robotic arm are the three-legged translational universal-prismatic-universal (UPU) and orientational universal-prismatic-spherical (UPS) parallel platforms. Each arm is composed of a large number of these modules having a very large number of degrees of freedom. Results of the workspace analysis are presented in tabular and graphical forms and the corresponding best designs are identified. All possible arm assembly configurations with two, three, and four parallel platform modules and one configuration with five parallel platform modules have been taken into consideration, analyzed, and compared. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Northeastern Univ, Dept Mech Ind & Mfg Engn, Robot & Mechatron Lab, Boston, MA 02115 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM mavro@coe.neu.edu NR 52 TC 5 Z9 5 U1 2 U2 9 PU SAGE PUBLICATIONS LTD PI LONDON PA 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND SN 0278-3649 EI 1741-3176 J9 INT J ROBOT RES JI Int. J. Robot. Res. PD JUN PY 2004 VL 23 IS 6 BP 643 EP 659 DI 10.1177/0278364904044406 PG 17 WC Robotics SC Robotics GA 828QJ UT WOS:000221987500006 ER PT J AU Stothers, RB AF Stothers, RB TI Ancient scientific basis of the "great serpent" from historical evidence SO ISIS LA English DT Article AB Zoological data and a growing mythology contributed to ancient Western knowledge about large serpents. Yet little modern attention has been paid to the sources, transmission, and receipt in the early Middle Ages of the ancients' information concerning "dragons" and "sea serpents." Real animals-primarily pythons and whales-lie behind the ancient stories. Other animals, conflations of different animals, simple misunderstandings, and willful exaggerations are found to account for the fanciful embellishments, but primitive myths played no significant role in this process during classical times. The expedition of Alexander the Great into India (327-325 B.C.) and the Bagradas River incident in North Africa (256 B.C.) had enormous repercussions on the development of serpent lore. Credible evidence is found for the presence of ancient populations of pythons living along the North African coast west of Egypt and along the coast of the Arabian Sea between the Indus River and the Strait of Hormuz-places where they no longer exist today. The maximum sizes of ancient pythons may have been greater than those of today's specimens. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Stothers, RB (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. NR 43 TC 2 Z9 2 U1 1 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0021-1753 J9 ISIS JI Isis PD JUN PY 2004 VL 95 IS 2 BP 220 EP 238 DI 10.1086/426195 PG 19 WC History & Philosophy Of Science SC History & Philosophy of Science GA 856GH UT WOS:000224033200002 PM 15490966 ER PT J AU Lovelace, JJ Soares, AS Bellamy, HD Sweet, RM Snell, EH Borgstahl, GEO AF Lovelace, JJ Soares, AS Bellamy, HD Sweet, RM Snell, EH Borgstahl, GEO TI First results of digital topography applied to macromolecular crystals SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID X-RAY TOPOGRAPHY; TETRAGONAL LYSOZYME; DIFFRACTION; RESOLUTION; PERFECTION AB An inexpensive digital CCD camera was used to record X-ray topographs directly from large imperfect crystals of cubic insulin. The topographs recorded were not as detailed as those which can be measured with film or emulsion plates, but do show great promise. Six reflections were recorded using a set of finely spaced stills encompassing the rocking curve of each reflection. A complete topographic reflection profile could be digitally imaged in minutes. Interesting and complex internal structure was observed by this technique. The CCD chip used in the camera has anti-blooming circuitry and produced good data quality, even when pixels became overloaded. C1 Univ Nebraska, Med Ctr, Eppley Inst Res Canc, Omaha, NE 68198 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. CAMD LSU, Baton Rouge, LA 70806 USA. NASA, George C Marshall Space Flight Ctr, NASA Lab Struct Biol, Huntsville, AL 35812 USA. RP Borgstahl, GEO (reprint author), Univ Nebraska, Med Ctr, Eppley Inst Res Canc, 987696 Nebraska Med Ctr, Omaha, NE 68198 USA. EM gborgstahl@unmc.edu RI Soares, Alexei/F-4800-2014 OI Soares, Alexei/0000-0002-6565-8503 NR 14 TC 7 Z9 7 U1 0 U2 0 PU BLACKWELL MUNKSGAARD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD JUN PY 2004 VL 37 BP 481 EP 485 DI 10.1107/S0021889804004303 PN 3 PG 5 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 820IM UT WOS:000221381500018 ER PT J AU Potter, RR Hong, YS Ciszak, EM AF Potter, RR Hong, YS Ciszak, EM TI Use of plastic capillaries for macromolecular crystallization SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID CRYSTALS; GROWTH AB Techniques of crystallization of biomolecules in plastic fluorocarbon-formulated capillaries (Nalgene 870 PFA tubing) are presented. These crystallization methods employ batch, free-interface liquid - liquid diffusion alone, or a combination with vapor diffusion. The growth of crystals of test proteins such as thaumatin and glucose isomerase, as well as of proteins studied in the laboratory, such as dihydrolipoamide dehydrogenase, has been demonstrated. Once the solutions were loaded in capillaries, they were stored in the tubes in frozen state at cryogenic temperatures until required for crystallization experiments. C1 NASA, Biol & Phys Space Res Lab, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Struct Biol Lab, Huntsville, AL 35812 USA. RP Ciszak, EM (reprint author), NASA, Biol & Phys Space Res Lab, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM ewa.m.ciszak@nasa.gov NR 7 TC 4 Z9 4 U1 0 U2 2 PU BLACKWELL MUNKSGAARD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD JUN PY 2004 VL 37 BP 500 EP 501 DI 10.1107/S0021889804005242 PN 3 PG 2 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 820IM UT WOS:000221381500022 ER PT J AU Gu, JJ Smith, EA Cooper, HJ Grose, A Liu, GS Merritt, JD Waterloo, MJ de Araujo, AC Nobre, AD Manzi, AO Marengo, J de Oliveira, PJ von Randow, C Norman, J Dias, PS AF Gu, JJ Smith, EA Cooper, HJ Grose, A Liu, GS Merritt, JD Waterloo, MJ de Araujo, AC Nobre, AD Manzi, AO Marengo, J de Oliveira, PJ von Randow, C Norman, J Dias, PS TI Modeling carbon sequestration over the large-scale Amazon basin, aided by satellite observations. Part I: Wet- and dry-season surface radiation budget flux and precipitation variability based on GOES retrievals SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID SIMPLE PHYSICAL MODEL; SOLAR-RADIATION; GLOBAL PRECIPITATION; CLIMATOLOGY PROJECT; RAIN-FOREST; ABSORPTION; ATMOSPHERE; IMAGERY; ENERGY; CLOUDS AB In this first part of a two-part investigation, large-scale Geostationary Operational Environmental Satellite (GOES) analyses over the Amazonia region have been carried out for March and October of 1999 to provide detailed information on surface radiation budget (SRB) and precipitation variability. SRB fluxes and rainfall are the two foremost cloud-modulated control variables that affect land surface processes, and they require specification at space-time resolutions concomitant with the changing cloud field to represent adequately the complex coupling of energy, water, and carbon budgets. These processes ultimately determine the relative variations in carbon sequestration and carbon dioxide release within a forest ecosystem. SRB and precipitation retrieval algorithms using GOES imager measurements are used to retrieve surface downward radiation and surface rain rates at high space - time resolutions for large-scale carbon budget modeling applications in conjunction with the Large-Scale Biosphere - Atmosphere Experiment in Amazonia. To validate the retrieval algorithms, instantaneous estimates of SRB fluxes and rain rates over 8 km 3 8 km areas were compared with 30-min-averaged surface measurements obtained from tower sites located near Ji-Paranaand Manaus in the states of Rondonia and Amazonas, respectively. Because of large aerosol concentrations originating from biomass burning during the dry season (i.e., September and October for purposes of this analysis), an aerosol index from the Total Ozone Mapping Spectrometer is used in the solar radiation retrieval algorithm. The validation comparisons indicate that bias errors for incoming total solar, photosynthetically active radiation ( PAR), and infrared flux retrievals are under 4%, 6%, and 3% of the mean values, respectively. Precision errors at the analyzed space time scales are on the order of 20%, 20%, and 5%. The visible and infrared satellite measurements used for precipitation retrieval do not directly detect rainfall processes, and yet they are responsive to the rapidly changing cloud fields, which are directly associated with precipitation life cycles over the Amazon basin. In conducting the validation analysis at high space - time scales, the comparisons indicate systematic bias uncertainties on the order of 25%. These uncertainties are comparable to published values from an independent assessment of bias uncertainties inherent to the current highest-quality satellite retrievals, that is, from the Tropical Rainfall Measuring Mission. Because precipitation is a weak direct control on photosynthesis for the Amazon ecosystem, that is, photosynthesis is dominated by the strong diurnal controls of incoming PAR and ambient air-canopy temperatures, such uncertainties are tolerable. By the same token, precipitation is a strong control on soil thermal properties and carbon respiration through soil moisture, but the latter is a time-integrating variable and thus inhibits introduction of modeling errors caused by random errors in the precipitation forcing. The investigation concludes with analysis of the monthly, daily, and diurnal variations intrinsic to SRB and rainfall processes over the Amazon basin, including explanations of how these variations arise during wet-and dry-season periods. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. Vrije Univ Amsterdam, Amsterdam, Netherlands. Inst Nacl de Pesquisas da Amazonia, Manaus, Amazonas, Brazil. CPTEC, INPE, Cachoeira Paulista, Brazil. Univ Wisconsin, Dept Soil Sci, Madison, WI 53706 USA. Univ Sao Paulo, Dept Atmospher Sci, Sao Paulo, Brazil. RP Smith, EA (reprint author), NASA, Goddard Space Flight Ctr, Code 912-1, Greenbelt, MD 20771 USA. EM eric.a.smith@nasa.gov RI von Randow, Celso/B-3335-2009; Liu, Guosheng/D-3479-2011; Marengo, Jose /J-9382-2012; Nobre, Antonio /H-4309-2012 OI von Randow, Celso/0000-0003-1045-4316; Liu, Guosheng/0000-0001-7899-6125; Marengo, Jose /0000-0002-8154-2762; Nobre, Antonio /0000-0001-6840-6398 NR 53 TC 4 Z9 4 U1 2 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUN PY 2004 VL 43 IS 6 BP 870 EP 886 DI 10.1175/1520-0450(2004)043<0870:MCSOTL>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 835CX UT WOS:000222458700004 ER PT J AU Shepherd, JM AF Shepherd, JM TI Comments on "Rainfall modification by major urban areas: Observations from spaceborne rain radar on the TRMM satellite'' - Reply SO JOURNAL OF APPLIED METEOROLOGY LA English DT Editorial Material ID ST-LOUIS; PRECIPITATION RADAR; HEAT-ISLAND; VALIDATION; PATTERNS; ATLANTA; MODEL; SITE; LAND AB Diem et al. have responded with critical comments as to whether urbanization-enhanced precipitation is maximized in the south-southeast of Atlanta, Georgia, as was recently documented by Shepherd et al. The reply herein offers both general and specific responses to the issues raised by Diem et al. C1 NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD 20771 USA. RP Shepherd, JM (reprint author), NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Code 912-0, Greenbelt, MD 20771 USA. EM marshall.shepherd@nasa.gov NR 38 TC 3 Z9 3 U1 1 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUN PY 2004 VL 43 IS 6 BP 951 EP 957 DI 10.1175/1520-0450(2004)043<0951:R>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 835CX UT WOS:000222458700011 ER PT J AU Lang, S Tao, WK Simpson, J Ferrier, B AF Lang, S Tao, WK Simpson, J Ferrier, B TI Comments on "Modeling of convective-stratiform precipitation processes: Sensitivity to partitioning methods'' - Reply SO JOURNAL OF APPLIED METEOROLOGY LA English DT Editorial Material ID MICROWAVE; CLOUD; PARAMETERIZATION; MICROPHYSICS; SIMULATIONS C1 NASA, Goddard Space Flight Ctr, SSAI, Mesoscale Atmospher Proc Branch,Lab Atmospheres, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. Natl Ctr Environm Predict, Environm Monitoring Ctr, Washington, DC USA. Sci Applicat Int Corp, Gen Sci Operat, Beltsville, MD USA. RP Lang, S (reprint author), NASA, Goddard Space Flight Ctr, SSAI, Mesoscale Atmospher Proc Branch,Lab Atmospheres, Code 912-0, Greenbelt, MD 20771 USA. EM lang@agnes.gsfc.nasa.gov NR 16 TC 2 Z9 2 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUN PY 2004 VL 43 IS 6 BP 962 EP 965 DI 10.1175/1520-0450(2004)043<0962:R>2.0.CO;2 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 835CX UT WOS:000222458700013 ER PT J AU Provenzano, V Shapiro, AJ Shull, RD King, T Canavan, E Shirron, P DiPirro, M AF Provenzano, V Shapiro, AJ Shull, RD King, T Canavan, E Shirron, P DiPirro, M TI Peak magnetocaloric effects in Al-Gd-Fe alloys SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 9th Joint Magnetism and Magnetic Materials Conference/ International Magnetics Conference CY JAN 05-09, 2004 CL Anaheim, CA ID TRANSITION AB The magnetocaloric properties of several AlxGdyFez (with x+y+z=100) ternary alloys have been determined between 2 and 300 K. Three distinct peaks in the magnetic entropy change DeltaS(m) versus T were found: a low-temperature peak (near 10 K), an intermediate temperature peak (80-160 K), and a higher temperature peak (210 to 280 K). The low-temperature peak coincides with a field-induced antiferromagnetic-to-ferromagnetic transition; the intermediate and high temperature peaks are associated with other magnetic transitions. Above 60 K, these alloys exhibited superparamagnetic behavior and possessed enhanced DeltaS(m) values, as predicted earlier for magnetic nanocomposites. (C) 2004 American Institute of Physics. C1 Natl Inst Stand & Technol, Magnet Mat Grp, Gaithersburg, MD 20899 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Provenzano, V (reprint author), Natl Inst Stand & Technol, Magnet Mat Grp, 100 Bur Dr,MS-8552, Gaithersburg, MD 20899 USA. RI Shull, Robert/F-5971-2013 NR 11 TC 7 Z9 7 U1 1 U2 13 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 2004 VL 95 IS 11 BP 6909 EP 6911 DI 10.1063/1.1667832 PN 2 PG 3 WC Physics, Applied SC Physics GA 824BE UT WOS:000221657900131 ER PT J AU Sundaresan, A Risin, D Pellis, NR AF Sundaresan, A Risin, D Pellis, NR TI Modeled microgravity-induced protein kinase C isoform expression in human lymphocytes SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE signal transduction; locomotion; immunity ID T-CELL; ACTIVATION; INHIBITION; LOCOMOTION AB In long-term space travel, the crew is exposed to microgravity and radiation that invoke potential hazards to the immune system. T cell activation is a critical step in the immune response. Receptor-mediated signaling is inhibited in both microgravity and modeled microgravity (MMG) as reflected by diminished DNA synthesis in peripheral blood lymphocytes and their locomotion through gelled type I collagen. Direct activation of protein kinase C (PKC) bypassing cell surface events using the phorbol ester PMA rescues MMG-inhibited lymphocyte activation and locomotion, whereas the calcium ionophore ionomycin had no rescue effect. Thus calcium-independent PKC isoforms may be affected in MMG-induced locomotion inhibition and rescue. Both calcium-dependent isoforms and calcium-independent PKC isoforms were investigated to assess their expression in lymphocytes in 1 g and MMG culture. Human lymphocytes were cultured and harvested at 24, 48, 72, and 96 h, and serial samples were assessed for locomotion by using type I collagen and expression of PKC isoforms. Expression of PKC-alpha, -delta, and -epsilon was assessed by RT-PCR, flow cytometry, and immunoblotting. Results indicated that PKC isoforms delta and epsilon were downregulated by >50% at the transcriptional and translational levels in MMG-cultured lymphocytes compared with 1-g controls. Events upstream of PKC, such as phosphorylation of phospholipase Cgamma in MMG, revealed accumulation of inactive enzyme. Depressed calcium-independent PKC isoforms may be a consequence of an upstream lesion in the signal transduction pathway. The differential response among calcium-dependent and calcium-independent isoforms may actually result from MMG intrusion events earlier than PKC, but after ligand-receptor interaction. C1 NASA, Lyndon B Johnson Space Ctr, Biol Syst Off, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Univ Space Res Assoc, Div Space Life Sci, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Biol Sci & Applicat Off, Houston, TX 77058 USA. RP Sundaresan, A (reprint author), NASA, Lyndon B Johnson Space Ctr, Biol Syst Off, 2101 NASA Pkwy,Mailcode SJ, Houston, TX 77058 USA. EM alamelu.sundaresan1@jsc.nasa.gov NR 13 TC 7 Z9 9 U1 0 U2 1 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD JUN PY 2004 VL 96 IS 6 BP 2028 EP 2033 DI 10.1152/japplphysiol.01248.2003 PG 6 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA 819EJ UT WOS:000221296600003 PM 14966022 ER PT J AU Gosselink, KL Roy, RR Zhong, H Grindeland, RE Bigbee, AJ Edgerton, VR AF Gosselink, KL Roy, RR Zhong, H Grindeland, RE Bigbee, AJ Edgerton, VR TI Vibration-induced activation of muscle afferents modulates bioassayable growth hormone release SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE pituitary; proprioception; tendon vibration; muscle afferent-pituitary axis ID RAT SOLEUS MUSCLE; SKELETAL-MUSCLE; CELL-FUNCTION; PITUITARY; SPACEFLIGHT; RESPONSES; EXERCISE; HETEROGENEITY; STIMULATION; PLASMA AB The effects of tendon vibration on bioassayable growth hormone (BGH) secretion from the pituitary gland were investigated in anesthetized adult male rats. The tendons from predominantly fast-twitch ankle extensor muscles (gastrocnemius and plantaris) or a predominantly slow-twitch ankle extensor (soleus) were vibrated by using a paradigm that selectively activates group Ia afferent fibers from muscle spindles. The lower hindlimb was secured with the muscles near physiological length, and the tendons were vibrated for 15 min at 150 Hz and a displacement of 1 mm. Control rats were prepared similarly, but the tendons were not vibrated. Compared with control, vibration of the tendons of the fast ankle extensors markedly increased (160%), whereas vibration of the slow soleus decreased (68%), BGH secretion. Complete denervation of the hindlimb had no independent effects on the normal resting levels of BGH, but it prevented the effects of tendon vibration on BGH secretion. The results are consistent with previous findings showing modulation of BGH release in response to in vivo activation or in situ electrical stimulation of muscle afferents (Bigbee AJ, Gosselink KL, Grindeland RE, Roy RR, Zhong H, and Edgerton VR. J Appl Physiol 89: 2174-2178, 2000; Gosselink KL, Grindeland RE, Roy RR, Zhong H, Bigbee AJ, and Edgerton VR. J Appl Physiol 88: 142-148, 2000; Gosselink KL, Grindeland RE, Roy RR, Zhong H, Bigbee AJ, Grossman EJ, and Edgerton VR. J Appl Physiol 84: 1425-1430, 1998). These data provide evidence that this previously described muscle afferent-pituitary axis is neurally mediated via group Ia afferents from peripheral skeletal muscle. Furthermore, these data show that activation of this group Ia afferent pathway from fast muscles enhances, whereas the same sensory afferent input from a slow muscle depresses, BGH release. C1 Univ Calif Los Angeles, Brain Res Inst, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Physiol Sci, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Neurobiol, Los Angeles, CA 90095 USA. NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. RP Roy, RR (reprint author), Univ Calif Los Angeles, Brain Res Inst, Box 951761,1321 Gonda Neurosci & Genet Bldg, Los Angeles, CA 90095 USA. EM rrr@ucla.edu FU NIDCR NIH HHS [DE-07212]; NINDS NIH HHS [NS-16333] NR 40 TC 12 Z9 14 U1 0 U2 0 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD JUN PY 2004 VL 96 IS 6 BP 2097 EP 2102 DI 10.1152/japplphysiol.00855.2003 PG 6 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA 819EJ UT WOS:000221296600010 PM 14766785 ER PT J AU Watenpaugh, DE Breit, GA Buckley, TM Ballard, RE Murthy, G Hargens, AR AF Watenpaugh, DE Breit, GA Buckley, TM Ballard, RE Murthy, G Hargens, AR TI Human cutaneous vascular responses to whole-body tilting, G(z) centrifugation, and LBNP SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE gravity; cutaneous circulation; hemodynamics; short- and long-arm centrifuges; microgravity countermeasures; lower body negative pressure ID NEGATIVE-PRESSURE; BLOOD-FLOW; ORTHOSTATIC STRESS; MICROVASCULAR FLOW; BED REST; MICROGRAVITY; TISSUE; SPACE; HEAD; POSITION AB We hypothesized that gravitational stimuli elicit cardiovascular responses in the following order with gravitational stress equalized at the level of the feet, from lowest to highest response: short- (SAC) and long-arm centrifugation (LAC), tilt, and lower body negative pressure (LBNP). Up to 15 healthy subjects underwent graded application of the four stimuli. Laser-Doppler flowmetry measured regional skin blood flow. At 0.6 G(z) (60 mmHg LBNP), tilt and LBNP similarly reduced leg skin blood flow to similar to36% of supine baseline levels. Flow increased back toward baseline levels at 80-100 mmHg LBNP yet remained stable during 0.8-1.0 G(z) tilt. Centrifugation usually produced less leg vasoconstriction than tilt or LBNP. Surprisingly, SAC and LAC did not differ significantly. Thigh responses were less definitive than leg responses. No gravitational vasoconstriction occurred in the neck. All conditions except SAC increased heart rate, according to our hypothesized order. LBNP may be a more effective and practical means of simulating cardiovascular effects of gravity than centrifugation. C1 NASA, Ames Res Ctr, Gravitat Res Branch, Moffett Field, CA 94035 USA. RP Watenpaugh, DE (reprint author), Naval Submarine Med Res Lab, Box 900, Groton, CT 06349 USA. EM watenpaugh@nsmrl.navy.mil NR 35 TC 24 Z9 24 U1 0 U2 3 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD JUN PY 2004 VL 96 IS 6 BP 2153 EP 2160 DI 10.1152/japplphysiol.00198.2003 PG 8 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA 819EJ UT WOS:000221296600019 PM 14766789 ER PT J AU King, MD Platnick, S Yang, P Arnold, GT Gray, MA Riedi, JC Ackerman, SA Liou, KN AF King, MD Platnick, S Yang, P Arnold, GT Gray, MA Riedi, JC Ackerman, SA Liou, KN TI Remote sensing of liquid water and ice cloud optical thickness and effective radius in the Arctic: Application of airborne multispectral MAS data SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID SOLAR-RADIATION MEASUREMENTS; CIRRUS CLOUDS; LIGHT-SCATTERING; SIMULATOR IMAGERY; SINGLE-SCATTERING; MODIS; CRYSTALS; MODELS; CONSTANTS; AEROSOL AB A multispectral scanning spectrometer was used to obtain measurements of the bidirectional reflectance and brightness temperature of clouds, sea ice, snow, and tundra surfaces at 50 discrete wavelengths between 0.47 and 14.0 mum. These observations were obtained from the NASA ER-2 aircraft as part of the First ISCCP ( International Satellite Cloud Climatology Project) Regional Experiment ( FIRE) Arctic Clouds Experiment, conducted over a 1600 km 3 500 km region of the north slope of Alaska and surrounding Beaufort and Chukchi Seas between 18 May and 6 June 1998. Multispectral images in eight distinct bands of the Moderate Resolution Imaging Spectroradiometer ( MODIS) Airborne Simulator (MAS) were used to derive a confidence in clear sky ( or alternatively the probability of cloud) over five different ecosystems. Based on the results of individual tests run as part of this cloud mask, an algorithm was developed to estimate the phase of the clouds ( liquid water, ice, or undetermined phase). Finally, the cloud optical thickness and effective radius were derived for both water and ice clouds that were detected during one flight line on 4 June. This analysis shows that the cloud mask developed for operational use on MODIS, and tested using MAS data in Alaska, is quite capable of distinguishing clouds from bright sea ice surfaces during daytime conditions in the high Arctic. Results of individual tests, however, make it difficult to distinguish ice clouds over snow and sea ice surfaces, so additional tests were added to enhance the confidence in the thermodynamic phase of clouds over the Chukchi Sea. The cloud optical thickness and effective radius retrievals used three distinct bands of the MAS, with a recently developed 1.62- and 2.13-mum-band algorithm being used quite successfully over snow and sea ice surfaces. These results are contrasted with a MODIS-based algorithm that relies on spectral reflectance at 0.87 and 2.13 mum. C1 NASA, Earth Sci Directorate, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX USA. Govt Serv Inc, L3 Commun, Landover, MD USA. Univ Sci & Technol Lille, Opt Atmospher Lab, Villeneuve Dascq, France. Univ Wisconsin, Dept Atmospher & Ocean Sci, Madison, WI USA. Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90024 USA. RP King, MD (reprint author), NASA, Earth Sci Directorate, Goddard Space Flight Ctr, Code 900, Greenbelt, MD 20771 USA. EM michael.d.king@nasa.gov RI Yang, Ping/B-4590-2011; King, Michael/C-7153-2011; Ackerman, Steven/G-1640-2011; Platnick, Steven/J-9982-2014 OI King, Michael/0000-0003-2645-7298; Ackerman, Steven/0000-0002-4476-0269; Platnick, Steven/0000-0003-3964-3567 NR 38 TC 103 Z9 106 U1 3 U2 16 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 2004 VL 21 IS 6 BP 857 EP 875 DI 10.1175/1520-0426(2004)021<0857:RSOLWA>2.0.CO;2 PG 19 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 829WN UT WOS:000222081900001 ER PT J AU Seneviratne, SI Viterbo, P Luthi, D Schar, C AF Seneviratne, SI Viterbo, P Luthi, D Schar, C TI Inferring changes in terrestrial water storage using ERA-40 reanalysis data: The Mississippi River basin SO JOURNAL OF CLIMATE LA English DT Article ID CENTRAL UNITED-STATES; REGIONAL CLIMATE MODEL; SOIL WETNESS PROJECT; ECMWF REANALYSIS; MOISTURE BUDGETS; VAPOR TRANSPORT; ENERGY BUDGETS; SUMMER DRYNESS; NORTH AMERICA; JULY 1993 AB Terrestrial water storage is an essential part of the hydrological cycle, encompassing crucial elements of the climate system, such as soil moisture, groundwater, snow, and land ice. On a regional scale, it is however not a readily measured variable and observations of its individual components are scarce. This study investigates the feasability of estimating monthly terrestrial water-storage variations from water-balance computations, using the following three variables: water vapor flux convergence, atmospheric water vapor content, and river runoff. The two first variables are available with high resolution and good accuracy in the present reanalysis datasets, and river runoff is commonly measured in most parts of the world. The applicability of this approach is tested in a 10-yr (1987-96) case study for the Mississippi River basin. Data used include European Centre for Medium-Range Weather Forecasts 40-yr reanalysis (ERA-40) data (water vapor flux and atmospheric water vapor content) and runoff observations from the United States Geological Survey. Results are presented for the whole Mississippi River basin and its subbasins, and for a smaller domain covering Illinois, where direct measurements of the main components of the terrestrial water storage (soil moisture, groundwater level, and snow cover) are available. The water-balance estimates of monthly terrestrial water-storage variations show excellent agreement with observations taken over Illinois. The mean seasonal cycle, as well as interannual variations, are captured with notable accuracy. Despite this excellent agreement, it is not straightforward to integrate the computed variations over longer time periods, because there are small systematic biases in the monthly changes. These biases likely result from inaccuracies of the atmospheric assimilation system used to estimate the atmospheric water vapor convergence and can be corrected in part with the application of a simple detrending procedure. It is noteworthy that the critical domain size for water-balance computations, using high-resolution reanalysis data such as ERA-40, appears to be much smaller than for raw radiosonde data. The Illinois domain has a size of only similar to2 x 10(5) km(2) and is shown to be suitable for the computation of the water-balance estimates. A comparison for other regions would be needed in order to confirm this result. C1 Swiss Fed Inst Technol, Inst Atmospher & Climate Sci, Zurich, Switzerland. European Ctr Medium Range Weather Forcasts, Reading, Berks, England. Swiss Fed Inst Technol, Inst Atmospher & Climate Sci, Zurich, Switzerland. RP Seneviratne, SI (reprint author), NASA, Goddard Space Flight Ctr, Goddard Earth Sci & Technol Ctr, Code 900-3,Bldg 33,Greenbelt Rd, Greenbelt, MD 20771 USA. EM senevira@janus.gsfc.nasa.gov RI Schar, Christoph/A-1033-2008; Viterbo, Pedro/B-7184-2008; Seneviratne, Sonia/G-8761-2011 OI Schar, Christoph/0000-0002-4171-1613; Viterbo, Pedro/0000-0001-6587-3062; Seneviratne, Sonia/0000-0001-9528-2917 NR 68 TC 89 Z9 91 U1 1 U2 11 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 PY 2004 VL 17 IS 11 BP 2039 EP 2057 DI 10.1175/1520-0442(2004)017<2039:ICITWS>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 825LB UT WOS:000221758000002 ER PT J AU Buckel, JA Sharack, BL Zdanowicz, VS AF Buckel, JA Sharack, BL Zdanowicz, VS TI Effect of diet on otolith composition in Pomatomus saltatrix, an estuarine piscivore SO JOURNAL OF FISH BIOLOGY LA English DT Article DE barium; diet; otolith chemistry; Pomatomus saltatrix; strontium ID THE-YEAR BLUEFISH; STRONTIUM-CALCIUM RATIOS; SHAD ALOSA-SAPIDISSIMA; ELEMENTAL COMPOSITION; FISH OTOLITHS; STRIPED BASS; SPATIAL VARIABILITY; JUVENILE BLUEFISH; NURSERY HABITATS; TRACE-ELEMENTS AB To test the hypothesis that elemental composition of otoliths (sagittae) could be influenced by differences in natural prey type, young-of-the-year bluefish Pomatomus saltatrix were captured immediately after their migration from oceanic waters into mid-Atlantic Bight estuaries and fed either shrimp, Crangon septemspinosa and Palaemonetes spp. or fish Menidia menidia under similar temperature and salinity regimes in two separate 60 day experiments. Unlimited rations of fish and shrimp prey were provided in the first experiment which led to differences in bluefish growth rate between the two prey treatments; fish prey was limited in the second experiment to ensure that growth rates of bluefish in the two prey treatments were similar. Concentrations of seven elements in bluefish otoliths were determined using solution-based inductively coupled plasma mass spectrometry (ICPMS). There was no significant effect of diet on five of the seven elements examined (Na, Mg, K, Ca and Mn). The levels of Sr and Ba in the otoliths of shrimp-fed bluefish, however, were significantly higher than fish-fed bluefish in both experiments. Concentrations of Ba in shrimp-fed bluefish otoliths were double that found in fish-fed bluefish. The results suggest that diet can explain some of the variation in otolith chemistry previously attributed to physical and chemical properties of the water. (C) 2004 The Fisheries Society of the British Isles. C1 N Carolina State Univ, Dept Zool, Ctr Marine Sci & Technol, Morehead City, NC 28557 USA. NOAA, Natl Marine Fisheries Serv, James J Howard Marine Sci Lab, Highlands, NJ 07732 USA. RP Buckel, JA (reprint author), N Carolina State Univ, Dept Zool, Ctr Marine Sci & Technol, 303 Coll Circle, Morehead City, NC 28557 USA. EM jeffrey_buckel@ncsu.edu NR 41 TC 58 Z9 60 U1 2 U2 24 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD JUN PY 2004 VL 64 IS 6 BP 1469 EP 1484 DI 10.1111/j.1095-8649.2004.00393.x PG 16 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 832TH UT WOS:000222289600001 ER PT J AU Driggers, WB Oakley, DA Ulrich, G Carlson, JK Cullum, BJ Dean, JM AF Driggers, WB Oakley, DA Ulrich, G Carlson, JK Cullum, BJ Dean, JM TI Reproductive biology of Carcharhinus acronotus in the coastal waters of South Carolina SO JOURNAL OF FISH BIOLOGY LA English DT Article DE carcharhinidae; gestation period; small coastal shark; spermatogenesis; vitellogenesis ID RHIZOPRIONODON-TERRAENOVAE RICHARDSON; ATLANTIC SHARPNOSE SHARK; WESTERN NORTH-ATLANTIC; GULF-OF-MEXICO; EMBRYONIC-DEVELOPMENT; BONNETHEAD SHARK; FINETOOTH SHARK; BLACKNOSE SHARK; SPHYRNA-TIBURO; UNITED-STATES AB The reproductive biology of blacknose sharks Carcharhinus acronotus in the western North Atlantic Ocean was studied by examining specimens collected in the coastal waters of South Carolina. Males begin the maturation process between 875 and 910mm fork length (L-F), as indicated by the presence of functional claspers and siphon sacs. The presence of vitellogenic oocytes and developing oviducal glands and uteri indicated that females begin to mature at c. 870 mm, L-F. Length at which 50% of the population reached maturity was 896 and 964 mm LF, equivalent to 4(.)3 and 4(.)5 years, for males and females, respectively. Gonado-somatic indices suggested that spermatogenesis and vitellogenesis began after December. Mating took place during the end of May and the beginning of June. Fertilization occurred during late June. and early July, suggesting that female blacknose sharks were capable of sperm storage. Based on the timing of fertilization and occurrence of females carrying near-term pups in late May and early June, the gestation period for blacknose sharks was c. 11 months. Female blacknose sharks reproduced biennially based on the absence of vitellogenic oocytes in near-term females and there being no indication of vitellogenesis in postpartum females. Male blacknose sharks were capable of reproducing annually as indicated by turgid genital ducts, which were observed in all mature males collected during late May and early June. (C) 2004 The Fisheries Society of the British Isles. C1 Univ S Carolina, Belle W Baruch Inst Marine & Coastal Sci, Columbia, SC 29208 USA. S Carolina Dept Nat Resources, Marine Resources Div, Charleston, SC 29412 USA. Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Panama City Lab, Panama City, FL 32408 USA. RP Driggers, WB (reprint author), Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Mississippi Labs, POB Drawer 1207, Pascagoula, MS 39568 USA. EM william.driggers@noaa.gov NR 30 TC 13 Z9 15 U1 0 U2 10 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD JUN PY 2004 VL 64 IS 6 BP 1540 EP 1551 DI 10.1111/j.1095-8649.2004.00408.x PG 12 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 832TH UT WOS:000222289600006 ER PT J AU Stoner, AW Ottmar, ML AF Stoner, AW Ottmar, ML TI Fish density and size alter Pacific halibut feeding: implications for stock assessment SO JOURNAL OF FISH BIOLOGY LA English DT Article DE competition; density-dependent; feeding motivation; Pacific halibuts social facilitation; stock assessment ID SABLEFISH ANOPLOPOMA-FIMBRIA; SCHOOLING FISH; BEHAVIOR; FACILITATION; ABUNDANCE; SALMON; BAIT; CATCHABILITY; SELECTIVITY; COMPETITION AB Laboratory experiments were conducted with Pacific halibut Hippoglossus stenolepis to test the hypothesis that responsiveness to food cues is density- and size-dependent. Tanks holding one, two and four fish were video-taped continuously before and after introduction of an olfactory cue and whole baits (squid). Pre-cue indices of activity did not vary with fish density. After olfactory stimulation, per capita activity was directly related to density, with no significant increase in activity by single fish. Numbers of baits located, attacked and consumed were directly related to fish density, and average times to first attack varied from 12 s in groups of four fish to >15 min in single fish. The latency period between location and attack decreased significantly with fish density. When large (43-55cm, total length, L-T) and small (31-38 cm L-T) Pacific halibut were tested together in pairs and groups of four fish, small individuals located baits first in 61% of the trials. Large fish, however, consumed all of the baits (except one) in trials where both large and small fish responded. Social facilitation in Pacific halibut feeding will result in a non-linear relationship between catch per unit effort and population density, and the size composition of fish captured may be influenced by interference competition. (C) 2004 The Fisheries Society of the British Isles. C1 NOAA, Fisheries Behav Ecol Program, Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, Newport, OR 97365 USA. RP Stoner, AW (reprint author), NOAA, Fisheries Behav Ecol Program, Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, 2030 S Marine Sci Dr, Newport, OR 97365 USA. EM al.stoner@noaa.gov NR 40 TC 21 Z9 21 U1 0 U2 5 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD JUN PY 2004 VL 64 IS 6 BP 1712 EP 1724 DI 10.1111/j.1095-8649.2004.00434.x PG 13 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 832TH UT WOS:000222289600018 ER PT J AU Reichle, RH Koster, RD Dong, JR Berg, AA AF Reichle, RH Koster, RD Dong, JR Berg, AA TI Global soil moisture from satellite observations, land surface models, and ground data: Implications for data assimilation SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID CATCHMENT-BASED APPROACH; NEAR-SURFACE; PRECIPITATION; VEGETATION; CLIMATOLOGY; PROJECT; IMPACT; METHODOLOGY; SIMULATIONS; RETRIEVAL AB Three independent surface soil moisture datasets for the period 1979-87 are compared: 1) global retrievals from the Scanning Multichannel Microwave Radiometer (SMMR), 2) global soil moisture derived from observed meteorological forcing using the NASA Catchment Land Surface Model, and 3) ground-based measurements in Eurasia North America from the Global Soil Moisture Data Bank. Time-average soil moisture fields from the satellite and the model largely agree in the global patterns of wet and dry regions. Moreover, the time series and anomaly time series of monthly mean satellite and model soil moisture are well correlated in the transition regions between wet and dry climates where land initialization may be important for seasonal climate prediction. However, the magnitudes of time-average soil moisture and soil moisture variability are markedly different between the datasets in many locations. Absolute soil moisture values from the satellite and the model are very different, and neither agrees better with ground data, implying that a "correct'' soil moisture climatology cannot be identified with confidence from the available global data. The discrepancies between the datasets point to a need for bias estimation and correction or rescaling before satellite soil moisture can be assimilated into land surface models. C1 NASA, Global Modeling & Assimilat Off, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. NASA, Hydrol Sci Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Guelph, Dept Geog, Guelph, ON N1G 2W1, Canada. RP NASA, Global Modeling & Assimilat Off, Goddard Space Flight Ctr, Code 900-3,Greenbelt Rd, Greenbelt, MD 20771 USA. EM reichle@janus.gsfc.nasa.gov RI Reichle, Rolf/E-1419-2012; Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 30 TC 129 Z9 130 U1 2 U2 15 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 2004 VL 5 IS 3 BP 430 EP 442 DI 10.1175/1525-7541(2004)005<0430:GSMFSO>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 829ZE UT WOS:000222090600005 ER PT J AU Koster, RD Suarez, MJ AF Koster, RD Suarez, MJ TI Suggestions in the observational record of land-atmosphere feedback operating at seasonal time scales SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID SOIL-MOISTURE; UNITED-STATES; TEMPERATURE PREDICTION; PRECIPITATION; BOUNDARY; RAINFALL AB Observed monthly precipitation anomalies are standardized across midlatitude land, and ergodicity is invoked to combine the spatially distributed data into probability density functions (pdfs) of precipitation conditioned on the strength of earlier anomalies. The conditional pdfs, though broad and overlapping, are indeed distinct at a high (99.9%) level of confidence. This implies a nonzero degree of predictability for midlatitude precipitation, even at 3-month leads. This behavior is reproduced by an AGCM only when land-atmosphere feedback in the model is enabled. C1 NASA, Global Modeling & Assimilat Off, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, Global Modeling & Assimilat Off, Goddard Space Flight Ctr, 900-3, Greenbelt, MD 20771 USA. EM randal.d.koster@nasa.gov RI Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 15 TC 26 Z9 26 U1 1 U2 10 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 2004 VL 5 IS 3 BP 567 EP 572 DI 10.1175/1525-7541(2004)005<0567:SITORO>2.0.CO;2 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 829ZE UT WOS:000222090600015 ER PT J AU Migdall, A Dowling, J AF Migdall, A Dowling, J TI Introduction to Journal of Modern Optics Special Issue on single-photon detectors, applications, and measurement methods SO JOURNAL OF MODERN OPTICS LA English DT Editorial Material C1 NIST, Gaithersburg, MD 20899 USA. CALTECH, NASA JPL, Pasadena, CA 91125 USA. RP Migdall, A (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 0 TC 26 Z9 26 U1 3 U2 9 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0950-0340 J9 J MOD OPTIC JI J. Mod. Opt. PD JUN-JUL PY 2004 VL 51 IS 9-10 BP 1265 EP 1266 DI 10.1080/09500340410001674411 PG 2 WC Optics SC Optics GA 831FV UT WOS:000222181200001 ER PT J AU Sun, XL Krainak, MA Abshire, JB Spinhirne, JD Trottier, C Davies, M Dautet, H Allan, GR Lukemire, AT Vandiver, JC AF Sun, XL Krainak, MA Abshire, JB Spinhirne, JD Trottier, C Davies, M Dautet, H Allan, GR Lukemire, AT Vandiver, JC TI Space-qualified silicon avalanche-photodiode single-photon-counting modules SO JOURNAL OF MODERN OPTICS LA English DT Article; Proceedings Paper CT Workshop on Single-Photon CY MAR 31-APR 01, 2003 CL Gaithersburg, MD ID LASER ALTIMETER; PERFORMANCE; INSTRUMENT; DAMAGE AB A space-qualified silicon avalanche-photodiode (APD) based single-photon-counting-module (SPCM) was developed for the Geoscience Laser Altimeter System (GLAS) on board NASA's Ice, Cloud, and Land Elevation Satellite (ICESat). Numerous improvements were made over the commercially available SPCMs in both performance and reliability. The measured optoelectronic parameters include, 65% photon detection efficiency at the 532 nm wavelength, 15-17 mega-counts per second (Mcps) maximum count rate and less than 200 s(-1) dark counts before exposure to space radiation. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. PerkinElmer Optoelect, Vaudreuil, PQ J7V 8P7, Canada. Sigma Res & Engn Corp, Lanham, MD 20706 USA. Space Power Elect Inc, Kathleen, GA 31047 USA. RP Sun, XL (reprint author), NASA, Goddard Space Flight Ctr, Code 924, Greenbelt, MD 20771 USA. RI Sun, Xiaoli/B-5120-2013; Abshire, James/I-2800-2013; Allan, Graham/D-3905-2013 NR 20 TC 30 Z9 31 U1 1 U2 8 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0950-0340 J9 J MOD OPTIC JI J. Mod. Opt. PD JUN-JUL PY 2004 VL 51 IS 9-10 BP 1333 EP 1350 DI 10.1080/09500340410001677085 PG 18 WC Optics SC Optics GA 831FV UT WOS:000222181200006 ER PT J AU Lee, H Yurtsever, U Kok, P Hockney, GM Adami, C Braunstein, SL Dowling, JP AF Lee, H Yurtsever, U Kok, P Hockney, GM Adami, C Braunstein, SL Dowling, JP TI Towards photostatistics from photon-number discriminating detectors SO JOURNAL OF MODERN OPTICS LA English DT Article; Proceedings Paper CT Workshop on Single-Photon CY MAR 31-APR 01, 2003 CL Gaithersburg, MD ID RESOLUTION; COUNTER; LIGHT AB We study the properties of a photodetector that has a number-resolving capability. In the absence of dark counts, due to its finite quantum efficiency, photodetection with such a detector can only eliminate the possibility that the incident field corresponds to a number of photons less than the detected photon number. We show that such a non-photon number-discriminating detector, however, provides a useful tool in the reconstruction of the photon number distribution of the incident field even in the presence of dark counts. C1 CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, Sect 367, Pasadena, CA 91109 USA. Hewlett Packard Labs, Bristol BS34 8QZ, Avon, England. Univ York, York YO10 5DD, N Yorkshire, England. RP Lee, H (reprint author), CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, Sect 367, MS 126-347,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Adami, Christoph/A-5181-2009; Braunstein, Samuel/A-5501-2009; Kok, Pieter/B-1658-2010; Adami, Christoph/A-9675-2011; DOWLING, JONATHAN/L-2749-2013 OI Adami, Christoph/0000-0002-2915-9504; NR 31 TC 26 Z9 26 U1 0 U2 3 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0950-0340 J9 J MOD OPTIC JI J. Mod. Opt. PD JUN-JUL PY 2004 VL 51 IS 9-10 BP 1517 EP 1528 DI 10.1080/09500340410001670901 PG 12 WC Optics SC Optics GA 831FV UT WOS:000222181200019 ER PT J AU Baskal, S Georgieva, E Kim, YS Noz, ME AF Baskal, S Georgieva, E Kim, YS Noz, ME TI Lorentz group in classical ray optics SO JOURNAL OF OPTICS B-QUANTUM AND SEMICLASSICAL OPTICS LA English DT Review DE Lorentz group in optics ID COVARIANT HARMONIC OSCILLATORS; GAUGE TRANSFORMATIONS; MASSLESS PARTICLES; POLARIZATION OPTICS; BEAM SPLITTER; QUARK-MODEL; ROTATIONS; REPRESENTATIONS; DECOMPOSITION; COHERENT AB It has been almost 100 years since Einstein formulated his special theory of relativity in 1905. He showed that the basic space-time symmetry is dictated by the Lorentz group. It is shown that this group of Lorentz transformations is not only applicable to special relativity, but also constitutes the scientific language for optical sciences. It is noted that coherent and squeezed states of light are representations of the Lorentz group. The Lorentz group is also the basic underlying language for classical ray optics, including polarization optics, interferometers, the Poincare sphere, one-lens optics, multi-lens optics, laser cavities, as well multilayer optics. C1 Middle E Tech Univ, Dept Phys, TR-06531 Ankara, Turkey. Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Laser & Electroopt Branch, Greenbelt, MD 20771 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. NYU, Dept Radiol, New York, NY 10016 USA. RP Baskal, S (reprint author), Middle E Tech Univ, Dept Phys, TR-06531 Ankara, Turkey. EM baskal@newton.physics.metu.edu.tr; egeorgie@pop500.gsfc.nasa.gov; yskim@physics.umd.edu; noz@nucmed.med.nyu.edu NR 52 TC 14 Z9 15 U1 0 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 1464-4266 J9 J OPT B-QUANTUM S O JI J. Opt. B-Quantum Semicl. Opt. PD JUN PY 2004 VL 6 IS 6 SI SI BP S455 EP S472 AR PII S1464-4266(04)74113-0 DI 10.1088/1464-4266/6/6/001 PG 18 WC Optics; Physics, Applied SC Optics; Physics GA 836YG UT WOS:000222591700002 ER PT J AU Worden, JR Bowman, KW Jones, DB AF Worden, JR Bowman, KW Jones, DB TI Two-dimensional characterization of atmospheric profile retrievals from limb sounding observations SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE remote sensing; limb sounding; horizontal inhomogeneity; retrieval ID MODEL DESCRIPTION; COOLING RATES; STRATOSPHERE; TEMPERATURE; SATELLITE; CHEMISTRY; TRANSPORT; FLUXES; OZONE; ATMOS AB Limb sounders measure atmospheric radiation that is dependent on atmospheric temperature and constituents that have a radial and angular distribution in Earth-centered coordinates. In order to evaluate the sensitivity of a limb retrieval to radial and angular distributions of trace gas concentrations, we perform and characterize one-dimensional (vertical) and two-dimensional (radial and angular) atmospheric profile retrievals. Our simulated atmosphere for these retrievals is a distribution of carbon monoxide (CO), which represents a plume off the coast of south-cast Asia. Both the one-dimensional (1D) and two-dimensional (2D) limb retrievals are characterized by evaluating their averaging kernels and error covariances on a radial and angular grid that spans the plume. We apply this 2D characterization of a limb retrieval to a comparison of the 2D retrieval with the 1D (vertical) retrieval. By characterizing a limb retrieval in two dimensions the location of the air mass where the retrievals are most sensitive can be determined. For this test case the retrievals are most sensitive to the CO concentrations about 2degrees latitude in front of the tangent point locations. We find the information content for the 2D retrieval is an order of magnitude larger and the degrees of freedom is about a factor of two lareer than that of the 1D retrieval primarily because the 2D retrieval can estimate angular distributions of CO concentrations. This 2D characterization allows the radial and angular resolution as well as the degrees of freedom and information content to be computed for these limb retrievals. We also use the 2D averaging kernel to develop a strategy for validation of a limb retrieval with an in situ measurement. (C) 2003 Elsevier Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. RP Worden, JR (reprint author), CALTECH, Jet Prop Lab, Div Earth & Space Sci, 4800 Oak Grove Dr,MS 183-301, Pasadena, CA 91109 USA. EM john.worden@jpl.nasa.gov RI Jones, Dylan/O-2475-2014 OI Jones, Dylan/0000-0002-1935-3725 NR 22 TC 14 Z9 14 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 JUN 1 PY 2004 VL 86 IS 1 BP 45 EP 71 DI 10.1016/S0022-4073(03)00274-7 PG 27 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 813VH UT WOS:000220934100004 ER PT J AU Edwards, HGM Villar, SEJ Bishop, JL Bloomfield, M AF Edwards, HGM Villar, SEJ Bishop, JL Bloomfield, M TI Raman spectroscopy of sediments from the Antarctic Dry Valleys; an analogue study for exploration of potential paleolakes on Mars SO JOURNAL OF RAMAN SPECTROSCOPY LA English DT Article DE micro-Raman spectroscopy; lacustrine sediments; Martian palaeolakes; Antarctic Dry Valleys; Mars analogues ID LAKE-HOARE; GEOCHEMICAL ANALYSES; GUSEV CRATER; REFLECTANCE; MATS AB A Raman spectroscopic study was performed on igneous sediments dominated by plagioclase, K-feldspar, quartz and pyroxene from the Dry Valleys region of Antarctica. Lakes from this region of Antarctica have been investigated as possible analogues for paleolake environments on early Mars. Gaining Raman spectra of such sediments provides compositional information for missions to Mars, and also the necessary ground truthing for use of Raman spectroscopy for exploration of geology, and perhaps biology, on Mars. Sediments measured in this study were collected from the perennially ice-covered Lake Hoare in the Taylor Valley and include surface sediments, and lakebottom sediments from oxic and anoxic zones of the lake. Micro-Raman spectroscopy provides a unique opportunity for in situ exploration of biogeochemical processes on the micron scale at field sites. For example, in these potential paleolake analogue sediments, similar to5 mum sized sulfide deposits were observed on the surface of quartz grains in one of the anoxic sediments. Small amounts of calcite, organics, clays and iron oxides/hydroxides were also identified. Copyright (C) 2004 John Wiley Sons, Ltd. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. Univ Bradford, Dept Chem & Forens Sci, Bradford BD7 1DP, W Yorkshire, England. Univ Burgos, Area Geodinam Interna, Burgos 09001, Spain. Renishaw PLC, Wotton Under Edge GL12 7DW, Glos, England. RP Bishop, JL (reprint author), NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. EM jbishop@mail.arc.nasa.gov RI Jorge-Villar, Susana/A-8927-2011 OI Jorge-Villar, Susana/0000-0003-1676-4438 NR 22 TC 16 Z9 16 U1 1 U2 6 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 0377-0486 J9 J RAMAN SPECTROSC JI J. Raman Spectrosc. PD JUN PY 2004 VL 35 IS 6 BP 458 EP 462 DI 10.1002/jrs.1174 PG 5 WC Spectroscopy SC Spectroscopy GA 835WK UT WOS:000222516000005 ER PT J AU Edwards, HGM Moody, CA Villar, SEJ Mancinelli, R AF Edwards, HGM Moody, CA Villar, SEJ Mancinelli, R TI Raman spectroscopy of desert varnishes and their rock substrata SO JOURNAL OF RAMAN SPECTROSCOPY LA English DT Article DE micro-Raman spectroscopy; desert varnish; cyanobacteria; epilithic lichen ID ANTARCTIC HABITATS; BIOMOLECULES; COMMUNITIES AB The Fourier-transform Raman spectra of desert varnish specimens and their rock substrata from locations in Colorado and Nevada, USA, are reported. The Colorado specimen exhibits molecular signatures for beta-carotene and scytonemin; the latter is a characteristic biomarker of cyanobacterial colonies and is produced by these organisms in response to high UV-radiation stress. The Nevada specimen, on the other hand, exhibited characteristic Raman bands arising from whewellite and lichen metabolites such as atranorin and paretin, indicative of an epilithic lichen colonization. The application of Raman microscopy for the identification of extinct or extant biological colonization of rocks in exposed hot desert environments could form a useful adjunct for database construction relevant to exobiological studies and key spectral bioindicators for the robotic exploration of planetary surfaces. Copyright (C) 2004 John Wiley Sons, Ltd. C1 Univ Bradford, Dept Chem & Forens Sci, Bradford BD7 1DP, W Yorkshire, England. Univ Burgos, Fac Humanidades & Educ, Area Geodinam Interna, Burgos 09001, Spain. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Edwards, HGM (reprint author), Univ Bradford, Dept Chem & Forens Sci, Bradford BD7 1DP, W Yorkshire, England. EM h.g.m.edwards@bradford.ac.uk RI Jorge-Villar, Susana/A-8927-2011 OI Jorge-Villar, Susana/0000-0003-1676-4438 NR 13 TC 13 Z9 14 U1 1 U2 6 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 0377-0486 J9 J RAMAN SPECTROSC JI J. Raman Spectrosc. PD JUN PY 2004 VL 35 IS 6 BP 475 EP 479 DI 10.1002/jrs.1170 PG 5 WC Spectroscopy SC Spectroscopy GA 835WK UT WOS:000222516000008 ER PT J AU Bishop, JL Murad, E AF Bishop, JL Murad, E TI Characterization of minerals and biogeochemical markers on Mars: A Raman and IR spectroscopic study of montmorillonite SO JOURNAL OF RAMAN SPECTROSCOPY LA English DT Article DE infrared spectroscopy; clay minerals; montmorillonite; carbonate; amorphous carbon ID SOCIETY SOURCE CLAYS; X-RAY-DIFFRACTION; BASE-LINE; IN-SITU; FT-RAMAN; LASER; SPECTRA; VIBRATIONS; DUST AB Raman spectroscopy is likely to be one of a number of instruments deployed to Mars on future landed missions. The goals of these missions will include characterizing the mineralogy of the rocks and soils, in addition to determining if the planet may be or may have been habitable for life. The astrobiology questions are linked to understanding the aqueous and biogeochemical history of Mars. Clay minerals are studied here because if they are found on Mars they may provide information about the geochemistry of the primary rocks and the aqueous history of the planet. This study compares Raman and IR spectra of the SWy-1, STx-1 and SAz-1 montmorillonites. These samples contain admixtures of organic material, carbonate, amorphous silica and fine-grained quartz, which can all be detected using Raman spectroscopy. Less than 0.1 wt% C as organic material was detected in each of the samples through peaks associated with CC or CH bonds. Carbonate was detected in the Raman spectra for the sample containing 1.65 wt% CO3 but not for 0.15 wt% CO3. Raman spectra exhibit unique bands near 200 and 700 cm(-1) that are due to tetrahedral SiO4 in layer silicates and vary depending on the mineral structure. Raman spectra of clay minerals also have unique metal-OH bending vibrations between 840 and 920 cm(-1) that provide information about the octahedral cations present. Copyright (C) 2004 John Wiley Sons, Ltd. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. Bayer Geol Landesamt, D-95603 Marktredwitz, Germany. RP NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. EM jbishop@mail.arc.nasa.gov NR 33 TC 37 Z9 37 U1 3 U2 36 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0377-0486 EI 1097-4555 J9 J RAMAN SPECTROSC JI J. Raman Spectrosc. PD JUN PY 2004 VL 35 IS 6 BP 480 EP 486 DI 10.1002/jrs.1173 PG 7 WC Spectroscopy SC Spectroscopy GA 835WK UT WOS:000222516000009 ER PT J AU Chamberlain, AL Fahrenholtz, WG Hilmas, GE Ellerby, DT AF Chamberlain, AL Fahrenholtz, WG Hilmas, GE Ellerby, DT TI High-strength zirconium diboride-based ceramics SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID MECHANICAL-PROPERTIES; ZRB2-BASED CERAMICS; BORON-CARBIDE; COMPOSITES; OXIDATION; MICROSTRUCTURE; ZRB2 AB Zirconium diboride (ZrB2) and ZrB2 ceramics containing 10, 20, and 30 vol% SiC particulates were prepared from commercially available powders by hot pressing. Four-point bend strength, fracture toughness, elastic modulus, and hardness were measured. Modulus and hardness did not vary significantly with SiC content. In contrast, strength and toughness increased as SiC content increased. Strength increased from 565 MPa for ZrB2 to > 1000 MPa for samples containing 20 or 30 vol% SiC. The increase in strength was attributed to a decrease in grain size and the presence of WC. C1 Univ Missouri, Dept Ceram Engn, Rolla, MO 65409 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Chamberlain, AL (reprint author), Univ Missouri, Dept Ceram Engn, Rolla, MO 65409 USA. OI Fahrenholtz, William/0000-0002-8497-0092 NR 23 TC 438 Z9 453 U1 5 U2 64 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43086-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD JUN PY 2004 VL 87 IS 6 BP 1170 EP 1172 PG 3 WC Materials Science, Ceramics SC Materials Science GA 829UN UT WOS:000222075800036 ER PT J AU Lyapustin, A Williams, DL Markham, B Irons, J Holben, B Wang, Y AF Lyapustin, A Williams, DL Markham, B Irons, J Holben, B Wang, Y TI A method for unbiased high-resolution aerosol retrieval from Landsat SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RADIATIVE-TRANSFER PROBLEM; GREENS-FUNCTION METHOD; OPTICAL-PROPERTIES; SURFACE; RADIANCE AB Because the land surface reflectance varies spatially, the atmospheric radiative transfer over land in clear-sky conditions is essentially three-dimensional. This is manifested through horizontal radiative fluxes that blur satellite images. It is important that the atmospheric blurring systematically increases the apparent brightness of the dark pixels. As a consequence, there are systematic biases in the satellite products of aerosol optical thickness and surface albedo over dark targets based on 1D theory, which may have a negative impact on climate research. Below, a new dark target method is presented for unbiased simultaneous retrieval of the aerosol model and optical thickness over land from Landsat Enhanced Thematic Mapper Plus (ETM+) data, based on 3D radiative transfer theory. The method automatically selects an aerosol model from a large set of candidate models using a statistical approach of the probability distribution function. The dark target method of aerosol retrieval in the blue and red bands relies on prediction of the surface reflectance in these bands from the shortwave infrared region (2.1-2.2 mum) based on the linear regression. In the Moderate Resolution Imaging Spectroradiometer (MODIS) algorithm, the regression coefficients are constants, whereas different studies indicate that they have seasonal and geographic variations. The work here shows that the accuracy of aerosol retrieval over land can be significantly increased based on ancillary information on the regional and seasonal distribution of the regression coefficients. This information, which is called surface climatology, can be derived globally around Aerosol Robotic Network (AERONET) sites, using AERONET aerosol and water vapor information for accurate atmospheric correction. This paper describes the developed method in application to Landsat data and its initial validation with AERONET measurements for a set of ETM+ images of the Washington-Baltimore area, and studies biases of 1D retrievals. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, GEST Ctr, Baltimore, MD 21228 USA. RP Lyapustin, A (reprint author), NASA, Goddard Space Flight Ctr, Mailcode 920, Greenbelt, MD 20771 USA. EM alyapust@pop900.gsfc.nasa.gov RI Irons, James/D-8535-2012; Markham, Brian/M-4842-2013; Lyapustin, Alexei/H-9924-2014 OI Markham, Brian/0000-0002-9612-8169; Lyapustin, Alexei/0000-0003-1105-5739 NR 21 TC 9 Z9 9 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUN PY 2004 VL 61 IS 11 BP 1233 EP 1244 DI 10.1175/1520-0469(2004)061<1233:AMFUHA>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 825XR UT WOS:000221792600002 ER PT J AU Frazin, RA Fischer, DG Carney, PS AF Frazin, RA Fischer, DG Carney, PS TI Information content of the near field: two-dimensional samples SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID INTERNAL-REFLECTION MICROSCOPY; INVERSE SCATTERING; RESOLUTION; OPTICS AB Limits on the effective resolution of many optical near-field experiments are investigated. The results are applicable to variants of total-internal-reflection microscopy (TIRM), photon-scanning-tunneling microscopy (PSTM), and near-field-scanning-optical microscopy (NSOM) in which the sample is weakly scattering and the direction of illumination may be controlled. Analytical expressions for the variance of the estimate of the complex susceptibility of an unknown two-dimensional object as a function of spatial frequency are obtained for Gaussian and Poisson noise models, and a model-independent measure is examined. The results are used to explore the transition from near-zone to far-zone detection. It is demonstrated that the information content of the measurements made at a distance of even one wavelength away from the sample is already not much different from the information content of the far field. (C) 2004 Optical Society of America. C1 Univ Illinois, Dept Elect & Comp Engn, Urbana, IL 61821 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Illinois, Coordinated Sci Lab, Urbana, IL 61821 USA. Univ Illinois, Beckman Inst Adv Sci & Technol, Dept Elect & Comp Sci, Urbana, IL 61821 USA. RP Carney, PS (reprint author), Univ Illinois, Dept Elect & Comp Engn, Urbana, IL 61821 USA. EM carney@uiuc.edu RI Frazin, Richard/J-2625-2012 NR 21 TC 7 Z9 7 U1 0 U2 0 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 JUN PY 2004 VL 21 IS 6 BP 1050 EP 1057 DI 10.1364/JOSAA.21.001050 PG 8 WC Optics SC Optics GA 823SL UT WOS:000221633300018 PM 15191187 ER PT J AU Launius, RD AF Launius, RD TI More wives than one: Transformation of the Mormon marriage system, 1840-1910 SO JOURNAL OF THE WEST LA English DT Book Review C1 NASA, Washington, DC 20546 USA. RP Launius, RD (reprint author), NASA, Washington, DC 20546 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU J WEST INC PI MANHATTAN PA P O BOX 1009, MANHATTAN, KS 66505-1009 USA SN 0022-5169 J9 J WEST JI J. West PD SUM PY 2004 VL 43 IS 3 BP 89 EP 89 PG 1 WC History SC History GA 866NL UT WOS:000224780100057 ER PT J AU Lombardo, V Buongiorno, MF Pieri, D Merucci, L AF Lombardo, V Buongiorno, MF Pieri, D Merucci, L TI Differences in Landsat TM derived lava flow thermal structures during summit and flank eruption at Mount Etna SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article DE Landsat TM; thermal structures; Mount Etna ID TEMPERATURE-MEASUREMENTS; ACTIVE VOLCANOS; EFFUSION RATE; INFRARED DATA; FIELDS; RESOLUTION; FEATURES; IDENTIFICATION; DISTRIBUTIONS; MORPHOLOGY AB The simultaneous solution of the Planck equation (the so-called "dual-band" technique) for two shortwave infrared Landsat Thematic Mapper (TM) bands allows an estimate of the fractional area of the hottest part of an active flow and the temperature of the cooler crust. Here, the dual-band method has been applied to a time series of Mount Etna eruptions. The frequency distribution of the fractional area of the hottest component reveals specific differences between summit and flank lava flows. The shape of the density function shows a trend consistent with a Gaussian distribution and suggests a relationship between the moments of the distribution and the emplacement environment. Because flow composition of Etnean lavas generally remains constant during the duration of their emplacement, it appears that the shape of any particular frequency distribution is probably related to fluid mechanical aspects of flow emplacement that affect flow velocity and flow heat loss and thus the rate of formation of the surface crust. These factors include the influence of topographical features such as changes in slope gradient, changes in volume effusion rate, and progressive downflow increases in bulk or effective viscosity. A form of the general theoretical solution for the 'dual-band' system, which illustrates the relationship between radiance in TM bands 5 and 7, corresponding to hot fractional area and crust temperature, is presented. Generally speaking, it appears that for a given flow at any point in time, larger fractional areas of exposed hot material are correlated with higher temperatures and that, while the overall shape of that distribution is common for the flows studied, its amplitude and slope reflect individual flow theological regimes. (C) 2004 Elsevier B.V. All rights reserved. C1 Ist Nazl Geofis & Vulcanol, I-00143 Rome, Italy. CALTECH, Jet Prop Lab, Earth & Space Sci Div, Pasadena, CA 91109 USA. RP Lombardo, V (reprint author), Ist Nazl Geofis & Vulcanol, Via Vigna Murata 605, I-00143 Rome, Italy. EM lombardo@ingv.it; buongiorno@ingv.it; dave@lithos.jpl.nasa.gov; merucci@ingv.it NR 56 TC 21 Z9 23 U1 0 U2 0 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 2004 VL 134 IS 1-2 BP 15 EP 34 DI 10.1016/j.jvolgeores.2003.12.006 PG 20 WC Geosciences, Multidisciplinary SC Geology GA 824GD UT WOS:000221673400002 ER PT J AU Kring, DA Horz, F Zurcher, L Fucugauchi, JU AF Kring, DA Horz, F Zurcher, L Fucugauchi, JU TI Impact lithologies and their emplacement in the Chicxulub impact crater: Initial results from the Chicxulub Scientific Drilling Project, Yaxcopoil, Mexico SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID CRETACEOUS-TERTIARY BOUNDARY; PEAK-RING FORMATION; MELT ROCK; RIES CRATER; CONSTRAINTS; HAITI; GLASS; SIZE; STRATIGRAPHY; SPHERULES AB The Chicxulub Scientific Drilling Project (CSDP), Mexico, produced a continuous core of material from depths of 404 to 1511 m in the Yaxcopoil-1 (Yax-1) borehole, revealing (top to bottom) Tertiary marine sediments, polymict breccias, an impact melt unit, and one or more blocks of Cretaceous target sediments that are crosscut with impact-generated dikes, in a region that lies between the peak ring and final crater rim. The impact melt and breccias in the Yax-1 borehole are 100 m thick, which is approximately 115 the thickness of breccias and melts exposed in the Yucatan-6 exploration hole, which is also thought to be located between the peak ring and final rim of the Chicxulub crater. The sequence and composition of impact melts and breccias are grossly similar to those in the Yucatan-6 hole. Compared to breccias in other impact craters, the Chicxulub breccias are incredibly rich in silicate melt fragments (up to 84% versus 30 to 50%, for example, in the Ries). The melt in the Yax-1 hole was produced largely from the silicate basement lithologies that lie beneath a 3 km-thick carbonate platform in the target area. Small amounts of immiscible molten carbonate were ejected with the silicate melt, and clastic carbonate often forms the matrix of the polymict breccias. The melt unit appears to have been deposited while molten but brecciated after solidification. The melt fragments in the polymict breccias appear to have solidified in flight, before deposition, and fractured during transport and deposition. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NASA, Lyndon B Johnson Space Ctr, Planetary Sci Branch, SN2, Houston, TX 77058 USA. Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico. RP Kring, DA (reprint author), Univ Arizona, Lunar & Planetary Lab, 1629 E Univ Blvd, Tucson, AZ 85721 USA. EM kring@lpl.arizona.edu NR 79 TC 37 Z9 37 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 JUN PY 2004 VL 39 IS 6 BP 879 EP 897 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 841OF UT WOS:000222939300009 ER PT J AU Druyan, LM Fulakeza, M Lonergan, P AF Druyan, LM Fulakeza, M Lonergan, P TI Land surface influences on the West African summer monsoon: Implications for synoptic disturbances SO METEOROLOGY AND ATMOSPHERIC PHYSICS LA English DT Article ID WAVE DISTURBANCES; EASTERLY WAVES; SAHEL RAINFALL; TEMPERATURES; SIMULATIONS; MOISTURE; MODEL; GCM AB The study examines regional atmospheric model (RM) simulations of the mean June-September (JJAS) climate and the implications of the mean state for the model representation of African wave disturbances (AWD). Two simulations are made with a version of the RM that computes soil moisture with multivariate functions that statistically relate it to rainfall, surface temperature, albedo, vegetation and terrain slope. These simulations differ according to the assignment of ground temperatures (Tg). While the control experiment is based on the fully interactive computation of soil moisture, the second experiment tests the response to fixed Tg whose seasonal means are more realistic than in the control within a swath along the Gulf of Guinea coast. A third simulation is made with the RM coupled to a sophisticated land surface process model (RM2). Results show a rather acute sensitivity of the mean circulation to land surface processes. The more realistic meridional temperature gradient created by fixing Tg in turn increased the vertical wind shear over West Africa and eliminated unrealistic westerly circulation at 700 mb. AWD composites were transformed from intense closed cyclonic circulations with copious rainfall to more realistic open waves that organized more moderate precipitation maxima. Lower vorticity variances in the specified change experiment imply that the open waves were characterized by more moderate vorticity extremes. Corresponding spectral amplitudes for 3-6 day periodicities of the 700 mb meridional wind were 40-80% of control values within the swath of maximum AWD activity. From among the three simulations, RM2 achieved seasonal mean precipitation, temperature, energy flux and circulation distributions that, despite some unrealistic features, were closest to observational evidence. RM2 AWD were much less intense and favored slightly longer periods. Results demonstrate that discrepancies in modeled ground temperatures caused by underestimating the cloudiness that intercepts short wave solar flux along a narrow swath of the West African coast have far-reaching consequences for the simulation of both the mean summer climate and individual synoptic disturbances. The study implies that this cooling along the Gulf of Guinea coast prevents AWD from developing into more intense storms with heavier precipitation. C1 Columbia Univ, Earth Inst, Ctr Climate Syst Res, NASA Goddard Inst Space Studies, New York, NY 10027 USA. NASA, Goddard Inst Space Studies, Stinger Ghaffarian Technol Inc, New York, NY 10025 USA. RP Druyan, LM (reprint author), Columbia Univ, Earth Inst, Ctr Climate Syst Res, NASA Goddard Inst Space Studies, New York, NY 10027 USA. EM Ldruyan@giss.nasa.gov NR 18 TC 7 Z9 7 U1 0 U2 3 PU SPRINGER WIEN PI VIENNA PA SACHSENPLATZ 4-6, PO BOX 89, A-1201 VIENNA, AUSTRIA SN 0177-7971 J9 METEOROL ATMOS PHYS JI Meteorol. Atmos. Phys. PD JUN PY 2004 VL 86 IS 3-4 BP 261 EP 273 DI 10.1007/s00703-003-0025-z PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 827VM UT WOS:000221931500007 ER PT J AU Nickerson, CA Ott, CM Wilson, JW Ramamurthy, R Pierson, DL AF Nickerson, CA Ott, CM Wilson, JW Ramamurthy, R Pierson, DL TI Microbial responses to microgravity and other low-shear environments SO MICROBIOLOGY AND MOLECULAR BIOLOGY REVIEWS LA English DT Review ID ROTATING-WALL BIOREACTOR; GENERAL STRESS-RESPONSE; MICROCIN B17 PRODUCTION; SIGMA-FACTOR KATF; ESCHERICHIA-COLI; SIMULATED MICROGRAVITY; BACILLUS-SUBTILIS; MODELED MICROGRAVITY; BACTERIAL ADHESION; SPACE-FLIGHT AB Microbial adaptation to environmental stimuli is essential for survival. While several of these stimuli have been studied in detail, recent studies have demonstrated an important role for a novel environmental parameter in which microgravity and the low fluid shear dynamics associated with microgravity globally regulate microbial gene expression, physiology, and pathogenesis. In addition to analyzing fundamental questions about microbial responses to space-flight, these studies have demonstrated important applications for microbial responses to a ground-based, low-shear stress environment similar to that encountered during spaceflight. Moreover, the low-shear growth environment sensed by microbes during microgravity of spaceflight and during ground-based microgravity analogue culture is relevant to those encountered during their natural life cycles on Earth. While no mechanism has been clearly defined to explain how the mechanical force of fluid shear transmits intracellular signals to microbial cells at the molecular level, the fact that cross talk exists between microbial signal transduction systems holds intriguing possibilities that future studies might reveal common mechanotransduction themes between these systems and those used to sense and respond to low-shear stress and changes in gravitation forces. The study of microbial mechanotransduction may identify common conserved mechanisms used by cells to perceive changes in mechanical and/or physical forces, and it has the potential to provide valuable insight for understanding mechanosensing mechanisms in higher organisms. This review summarizes recent and future research trends aimed at understanding the dynamic effects of changes in the mechanical forces that occur in microgravity and other low-shear environments on a wide variety of important microbial parameters. C1 Tulane Univ, Sch Med, Dept Microbiol & Immunol, Program Mol Pathogenesis & Immun, New Orleans, LA 70112 USA. NASA, Lyndon B Johnson Space Ctr, EASI Wyle Labs, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Habitabil & Environm Factors Off, Houston, TX 77058 USA. RP Nickerson, CA (reprint author), Tulane Univ, Sch Med, Dept Microbiol & Immunol, Program Mol Pathogenesis & Immun, SL38,1430 Tulane Ave, New Orleans, LA 70112 USA. EM cnicker@tulane.edu NR 105 TC 119 Z9 130 U1 4 U2 40 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 1092-2172 J9 MICROBIOL MOL BIOL R JI Microbiol. Mol. Biol. Rev. PD JUN PY 2004 VL 68 IS 2 BP 345 EP + DI 10.1128/MMBR.68.2.345-361.2004 PG 18 WC Microbiology SC Microbiology GA 829VD UT WOS:000222077500009 PM 15187188 ER PT J AU Sudbrack, CK Isheim, D Noebe, RD Jacobson, NS Seidman, DN AF Sudbrack, CK Isheim, D Noebe, RD Jacobson, NS Seidman, DN TI The influence of tungsten on the chemical composition of a temporally evolving nanostructure of a model Ni-Al-Cr superalloy SO MICROSCOPY AND MICROANALYSIS LA English DT Article; Proceedings Paper CT Microscopy and Microanalysis 2002 Meeting CY AUG 05-08, 2002 CL QUEBEC CITY, CANADA DE nickel-base superalloy; three-dimensional atom-probe microscopy; tungsten; aluminum; chromium; temporal evolution; decomposition; coarsening; nanostructure; partitioning ratio; proxigram ID 3-DIMENSIONAL ATOM-PROBE; NICKEL-BASE SUPERALLOYS; RANGE PROFILES; MICROSCOPY; SCALE; PHASE; ALLOY; PRECIPITATION; CALIBRATION; DIFFUSIVITY AB The influence of W on the temporal evolution of gamma' precipitation toward equilibrium in a model Ni-Al-Cr alloy is investigated by three-dimensional atom-probe (3DAP) microscopy and transmission electron microscopy (TEM). We report on the alloys Ni-10 Al-8.5 Cr (at.%) and Ni-10 Al-8.5 Cr-2 W (at.%), which were aged isothermally in the gamma + gamma' two-phase field at 1073 K, for times ranging from 0.25 to 264 h. Spheroidal-shaped gamma' precipitates, 5-15 nm diameter, form during quenching from above the solvus temperature in both alloys at a high number density (similar to10(23) m(-3)). As gamma' precipitates grow with aging at 1073 K, a transition from spheriodal- to cuboidal-shaped precipitates is observed in both alloys. The elemental partitioning and spatially resolved concentration profiles across the gamma' precipitates are obtained as a function of aging time from three-dimensional atom-by-atom reconstructions. Proximity histogram concentration profiles (Hellman et al., 2000) of the quaternary alloy demonstrate that W concentration gradients exist in gamma' precipitates in the as-quenched and 0.25-h aging states, which disappear after 1 h of aging. The diffusion coefficient of W in gamma' is estimated to be 6.2 x 10(-20) m(2) s(-1) at 1073 K. The W addition decreases the coarsening rate constant, and leads to stronger partitioning of Al to gamma' and Cr to gamma. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. NASA Glenn Res Ctr, Cleveland, OH 44135 USA. RP Seidman, DN (reprint author), Northwestern Univ, Dept Mat Sci & Engn, 2220 Campus Dr, Evanston, IL 60208 USA. EM d-seidman@northwestern.edu RI Seidman, David/B-6697-2009; Isheim, Dieter/B-7524-2009; Jacobson, Nathan/A-9411-2009 NR 36 TC 42 Z9 42 U1 4 U2 13 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH ST, NEW YORK, NY 10011-4211 USA SN 1431-9276 J9 MICROSC MICROANAL JI Microsc. microanal. PD JUN PY 2004 VL 10 IS 3 BP 355 EP 365 DI 10.1017/S1431927604040589 PG 11 WC Materials Science, Multidisciplinary; Microscopy SC Materials Science; Microscopy GA 824KZ UT WOS:000221686800006 PM 15233854 ER PT J AU Champion, DJ Lorimer, DR McLaughlin, MA Cordes, JA Arzoumanian, Z Weisberg, JM Taylor, JH AF Champion, DJ Lorimer, DR McLaughlin, MA Cordes, JA Arzoumanian, Z Weisberg, JM Taylor, JH TI PSR J1829+2456: a relativistic binary pulsar SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE pulsars : general; pulsars : individual J1829+2456 ID GAMMA-RAY SOURCES; RADIO PULSARS; GRAVITATIONAL-RADIATION; SYSTEM; DISCOVERY; MASSES; POPULATION; GRAVITY; ORBIT AB We report the discovery of a new binary pulsar, PSR J1829+2456, found during a mid-latitude drift-scan survey with the Arecibo telescope. Our initial timing observations show the 41-ms pulsar to be in a 28-h, slightly eccentric, binary orbit. The advance of periastron (omega) over dot = 0.degrees28 +/- 0.degrees01 yr(-1) is derived from our timing observations spanning 200 d. Assuming that the advance of periastron is purely relativistic and a reasonable range of neutron star masses for PSR J1829+2456, we constrain the companion mass to be between 1.22 and 1.38 M., making it likely to be another neutron star. We also place a firm upper limit on the pulsar mass of 1.38 M.. The expected coalescence time due to gravitational wave emission is long (similar to60 Gyr), and this system will not significantly impact upon calculations of merger rates that are relevant to upcoming instruments such as LIGO. C1 Univ Manchester, Jodrell Bank Observ, Macclesfield SK11 9DL, Cheshire, England. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. NASA, Goddard Space Flight Ctr, USRA, LHEA, Greenbelt, MD 20771 USA. Carleton Coll, Dept Phys & Astron, Northfield, MN 55057 USA. Princeton Univ, Joseph Henry Labs, Princeton, NJ 08544 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. RP Champion, DJ (reprint author), Univ Manchester, Jodrell Bank Observ, Macclesfield SK11 9DL, Cheshire, England. EM champion@jb.man.ac.uk OI Champion, David/0000-0003-1361-7723 NR 33 TC 53 Z9 56 U1 0 U2 2 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUN 1 PY 2004 VL 350 IS 4 BP L61 EP L65 DI 10.1111/j.1365-2966.2004.07862.x PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 828EY UT WOS:000221957800001 ER PT J AU Jones, C Waliser, DE Lau, KM Stern, W AF Jones, C Waliser, DE Lau, KM Stern, W TI The Madden-Julian oscillation and its impact on Northern Hemisphere weather predictability SO MONTHLY WEATHER REVIEW LA English DT Article ID EXTREME PRECIPITATION EVENTS; OUTGOING LONGWAVE RADIATION; INTRASEASONAL TIME SCALES; AMERICAN-MONSOON-SYSTEM; CUMULUS CLOUD ENSEMBLE; GEOPOTENTIAL HEIGHT; TROPICAL CONVECTION; LIFE-CYCLE; WINTER; MODEL AB The Madden-Julian oscillation (MJO) is known as the dominant mode of tropical intraseasonal variability and has an important role in the coupled-atmosphere system. This study uses numerical model experiments to investigate the influence of the MJO activity on weather predictability in the midlatitudes of the Northern Hemisphere. The National Aeronautics and Space Administration ( NASA) Goddard Laboratory for the Atmospheres (GLA) general circulation model was used in a 10-yr simulation with fixed climatological SSTs to generate a control dataset as well as to select initial conditions for active MJO periods and "Null'' cases. Two perturbation numerical experiments were performed for the 75 cases selected [( 4 MJO phases 1 Null phase) 3 15 initial conditions in each]. For each alternative initial condition, the model was integrated for 90 days. Mean anomaly correlations and standardized root-mean-square errors in the midlatitudes of the Northern Hemisphere (20degrees-60degreesN) were computed to assess predictability characteristics. The analyses of 500-hPa geopotential height, 200-hPa streamfunction, and 850-hPa zonal wind component systematically show larger predictability (similar to2-3 days) during periods of active MJO as opposed to quiescent episodes of the oscillation. While further studies are necessary to investigate possible model sensitivity, the results shown here highlight the importance of the MJO in modulating weather variability and show the importance of improving the representation of the MJO in operational numerical weather forecast models. C1 Univ Calif Santa Barbara, Inst Computat Earth Syst Sci, Santa Barbara, CA 93106 USA. SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Stony Brook, NY 11794 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. Princeton Univ, Geophys Fluid Dynam Lab, Princeton, NJ 08544 USA. RP Univ Calif Santa Barbara, Inst Computat Earth Syst Sci, Santa Barbara, CA 93106 USA. EM cjones@icess.ucsb.edu RI Lau, William /E-1510-2012; Jones, Charles/I-4574-2012 OI Lau, William /0000-0002-3587-3691; Jones, Charles/0000-0003-4808-6977 NR 52 TC 53 Z9 54 U1 1 U2 12 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 EI 1520-0493 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUN PY 2004 VL 132 IS 6 BP 1462 EP 1471 DI 10.1175/1520-0493(2004)132<1462:TMOAII>2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 829ZF UT WOS:000222090700010 ER PT J AU Poggi, MA Boyles, JS Bottomley, LA AF Poggi, MA Boyles, JS Bottomley, LA TI Measuring the compression of a carbon nanospring SO NANO LETTERS LA English DT Article ID ATOMIC-FORCE MICROSCOPY; SCANNING PROBE MICROSCOPY; NANOTUBES; COMPOSITES; TIPS; CANTILEVERS; TECHNOLOGY; RESONANCES; MECHANICS; SURFACES AB The mechanical response of a multiwalled carbon nanospring was examined with an atomic force microscope. Cantilever deflection, oscillation amplitude, and resonance were simultaneously monitored during the cycled movement of the scanner. A nonlinear response of the nanospring was observed, consistent with compression and buckling of the nanospring. This is the first reported measurement of a shift in the cantilever resonance frequency as a result of the interaction of a nanospring-tipped cantilever with the substrate. C1 Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. Georgia Inst Technol, George W Woodruff Sch Mech Engn, Atlanta, GA 30332 USA. NASA, Ames Res Ctr, ELORET Corp, Moffett Field, CA 94035 USA. NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. RP Bottomley, LA (reprint author), Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. EM lawrence.bottomley@chemistry.gatech.edu RI Lillehei, Peter/C-9196-2009; OI Lillehei, Peter/0000-0001-8183-9980; Bottomley, Lawrence/0000-0002-2325-9862 NR 46 TC 43 Z9 45 U1 1 U2 18 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 2004 VL 4 IS 6 BP 1009 EP 1016 DI 10.1021/0497023 PG 8 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 828MZ UT WOS:000221978700002 ER PT J AU Paulin, MG Hoffman, LF Assad, C AF Paulin, MG Hoffman, LF Assad, C TI Distributed coding by single spikes in the bullfrog vestibular nerve: a basis for dynamical computation in neural systems SO NEUROCOMPUTING LA English DT Article; Proceedings Paper CT 12th Annual Computational Neuroscience Meeting (CSN 03) CY JUL 05-09, 2003 CL Alicante, SPAIN DE spike train; information theory; neural computation; cerebellum ID WHITE-NOISE INPUTS; AFFERENT RESPONSES AB We recorded spike trains from bullfrog semicircular canal afferent neurons during broad-band rotational stimulation. Conditional probability density functions for head state at spike times have smaller entropy than the unconditional distribution of head states, showing that individual spikes transmit on average about 0.1-1 bits of information about head state. This shows that it is possible to treat single spikes as measurements or assertions about head state. Building on this observation, we show how single spikes may be treated as operands in neural computation. (C) 2004 Elsevier B.V. All rights reserved. C1 Univ Otago, Dept Zool, Otago, New Zealand. Univ Otago, Ctr Neurosci, Otago, New Zealand. Univ Calif Los Angeles, Sch Med, Div Head & Neck Surg, Los Angeles, CA 90024 USA. NASA, Jet Prop Lab, Bioinspired Technol & Syst Grp, Pasadena, CA USA. RP Paulin, MG (reprint author), Univ Otago, Dept Zool, Otago, New Zealand. EM mike.paulin@stonebow.otago.ac.nz NR 6 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0925-2312 J9 NEUROCOMPUTING JI Neurocomputing PD JUN PY 2004 VL 58 BP 73 EP 77 DI 10.1016/j.neucom.2004.01.025 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA 832CX UT WOS:000222245900013 ER PT J AU Favre, P Petrucci, PO Beckmann, V Courvoisier, TJL AF Favre, P Petrucci, PO Beckmann, V Courvoisier, TJL TI BeppoSAX observations of the quasar Markarian 205 SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 2nd BeppoSAX Conference on Restless High-Engery Universe CY MAY 05-08, 2003 CL Amsterdam, NETHERLANDS SP Royal Netherlands Acad Arts & Sci, Acad Dei Lincei Rome ID X-RAY-SPECTRA; BUMP AB We present the first BeppoSAX observation (0.1 to 220 keV) of the quasar Mrk 205. We have searched for the unusual Fe line profile claimed in the XMM-Newton spectrum which has been widely discussed in recent literature. We find no evidence for a broad, ionized Fe line component in our data. We find that if the continuum is modeled with a Compton reflection from cold material component, the line strength diminishes, in agreement with a recent re-analysis of the XMM-Newton data, but with better constraints on the reflection component thanks to the PDS instrument (15-220 keV). We interpret this fact as another indication for illumination of a distant and cold material rather than reprocessing in the highly ionized inner parts of an accretion disk. We detect for the first time a Compton hump in this object. However we cannot constrain the presence of a high energy cutoff. We confirm the existence of a variable soft excess. C1 INTEGRAL, Sci Data Ctr, CH-1290 Versoix, Switzerland. Observ Geneva, CH-1290 Sauverny, Switzerland. Lab Astrophys Grenoble, F-38041 Grenoble, France. Univ Maryland, Joint Ctr Astrophys, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Favre, P (reprint author), INTEGRAL, Sci Data Ctr, 16 Ch Ecogia, CH-1290 Versoix, Switzerland. NR 11 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUN PY 2004 VL 132 BP 173 EP 176 DI 10.1016/j.nuclphysbps.2004.04.026 PG 4 WC Physics, Particles & Fields SC Physics GA 845FX UT WOS:000223224300028 ER PT J AU Lamb, DQ Ricker, GR Atteia, JL Barraud, C Boer, M Braga, J Butler, N Cline, T Crew, GB Dezalay, JP Donaghy, TQ Doty, JP Dullighan, A Fenimore, EE Galassi, M Graziani, C Hurley, K Jernigan, JG Kawai, N Levine, A Manchanda, R Matsuoka, M Martel, F Monnelly, G Morgan, G Olive, JF Pizzichini, G Prigozhin, G Sakamnoto, T Shirasaki, Y Suzuki, M Takagishi, K Tamagawa, T Torii, K Vanderspek, R Vedrenne, G Villasenor, J Woosley, SE Yamauchi, M Yoshida, A AF Lamb, DQ Ricker, GR Atteia, JL Barraud, C Boer, M Braga, J Butler, N Cline, T Crew, GB Dezalay, JP Donaghy, TQ Doty, JP Dullighan, A Fenimore, EE Galassi, M Graziani, C Hurley, K Jernigan, JG Kawai, N Levine, A Manchanda, R Matsuoka, M Martel, F Monnelly, G Morgan, G Olive, JF Pizzichini, G Prigozhin, G Sakamnoto, T Shirasaki, Y Suzuki, M Takagishi, K Tamagawa, T Torii, K Vanderspek, R Vedrenne, G Villasenor, J Woosley, SE Yamauchi, M Yoshida, A TI Scientific highlights of the HETE-2 mission SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 2nd BeppoSAX Conference on Restless High-Energy Universe CY MAY 05-08, 2003 CL Amsterdam, NETHERLANDS SP Royal Netherlands Acad Arts & Sci, Acad Dei Lincei Rome ID GAMMA-RAY BURSTS; EARLY OPTICAL-EMISSION; EARLY AFTERGLOW; HIGH REDSHIFTS; STAR-FORMATION; UNIVERSE; SUPERNOVA; DISCOVERY; POLARIZATION; REIONIZATION AB The HETE-2 mission has been highly productive. It has observed more than 250 GRBs so far. It is currently localizing 25 - 30 GRBs per year, and has localized 43 GRBs to date. Twenty-one of these localizations have led to the detection of X-ray, optical, or radio afterglows, and as of now, 11 of the bursts with afterglows have known redshifts. HETE-2 has confirmed the connection between GRBs and Type Ic supernovae, a singular achievement and certainly one of the scientific highlights of the mission so far. It has provided evidence that the isotropic-equivalent energies and luminosities of GRBs are correlated with redshift, implying that GRBs and their progenitors evolve strongly with redshift. Both of these results have profound implications for the nature of GRB progenitors and for the use of GRBs as a probe of cosmology and the early universe. HETE-2 has placed severe constraints on any X-ray or optical afterglow of a short GRB. It is also solving the mystery of "optically dark" GRBs, and revealing the nature of X-ray flashes. C1 Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Inst Nacl Pesquisas Espaciais, BR-12227010 Sao Jose Dos Campos, Brazil. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Los Alamos Natl Lab, Los Alamos, NM USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Tokyo Inst Technol, Tokyo 152, Japan. Tata Inst, Dept Astron & Astrophys, Bombay 400005, Maharashtra, India. NASDA, Tokyo, Japan. CNR, I-00185 Rome, Italy. Natl Astron Observ, Tokyo 181, Japan. Miyazaki Univ, Fac Engn, Miyazaki 8892192, Japan. RIKEN, Inst Phys & Chem Res, Tokyo, Japan. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. Aoyama Univ, Tokyo, Japan. RP Lamb, DQ (reprint author), Univ Chicago, Dept Astron & Astrophys, 5640 S Ellis Ave, Chicago, IL 60637 USA. OI Boer, Michel/0000-0001-9157-4349 NR 59 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUN PY 2004 VL 132 BP 279 EP 288 DI 10.1016/j.nuclphysbps.2004.04.049 PG 10 WC Physics, Particles & Fields SC Physics GA 845FX UT WOS:000223224300051 ER PT J AU Beckmann, V Borkowski, J Courvoisier, TJL Gotz, D Favre, P Hudec, R Mereghetti, S Shaw, SE von Kienlin, A Wigger, C AF Beckmann, V Borkowski, J Courvoisier, TJL Gotz, D Favre, P Hudec, R Mereghetti, S Shaw, SE von Kienlin, A Wigger, C TI Time resolved spectroscopy of GRB030501 using INTEGRAL SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 2nd BeppoSAX Conference on Restless High-Engery Universe CY MAY 05-08, 2003 CL Amsterdam, NETHERLANDS SP Royal Netherlands Acad Arts & Sci, Acad Dei Lincei Rome ID GAMMA-RAY BURST; BATSE OBSERVATIONS; BRIGHT; SPECTRA AB The Gamma-ray instruments on-board INTEGRAL offer a unique opportunity to perform time resolved analysis on GRBs. The imager IBIS allows accurate positioning of GRBs and broad band spectral analysis, while SPI provides high resolution spectroscopy. GRB 030501 was discovered by the INTEGRAL Burst Alert System in the ISGRI field of view. Although the burst was fairly weak (fluence F20-200 keV similar or equal to 3.5 x 10(-6) erg cm(-2)) it was possible to perform time resolved spectroscopy with a resolution of a few seconds. The GRB shows a spectrum in the 20 - 400 keV range which is consistent with a spectral photon index Gamma = -1.8. No emission line or spectral break was detectable in the spectrum. Although the flux seems to be correlated with the hardness of the GRB spectrum, there is no clear soft to hard evolution seen over the duration of the burst. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. INTEGRAL Sci Data Ctr, CH-1290 Chavannes Des Bois, Switzerland. CNR, Ist Astrofis Spaziale & Fis Cosmica, I-20133 Milan, Italy. Acad Sci Czech Republ, Inst Astron, CS-25165 Ondrejov, Czech Republic. Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. RP Beckmann, V (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Hudec, Rene/G-9018-2014; OI MEREGHETTI, SANDRO/0000-0003-3259-7801 NR 21 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUN PY 2004 VL 132 BP 301 EP 304 DI 10.1016/j.nuclphysbps.2004.04.052 PG 4 WC Physics, Particles & Fields SC Physics GA 845FX UT WOS:000223224300054 ER PT J AU Weisskopf, MC Becker, W Swartz, DA Pavlov, GG Elsner, RF Grindlay, J Mignani, R Tennant, AF Backer, D Pulone, L Testa, V AF Weisskopf, MC Becker, W Swartz, DA Pavlov, GG Elsner, RF Grindlay, J Mignani, R Tennant, AF Backer, D Pulone, L Testa, V TI Chandra X-Ray observatory observations of the globular cluster M28 and its millisecond pulsar PSR B1821-24 SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 2nd BeppoSAX Conference on Restless High-Engery Universe CY MAY 05-08, 2003 CL Amsterdam, NETHERLANDS SP Royal Netherlands Acad Arts & Sci, Acad Dei Lincei Rome ID NEUTRON-STAR; ATMOSPHERES; EMISSION AB We discuss the results of the first Chandra X-Ray Observatory observations of the globular cluster M28 (NGC 6626). We detect 46 X-ray sources of which 12 lie within one core radius of the center. We measure the radial distribution of the X-ray sources and fit it to a King profile finding a core radius of r(c,x) approximate to 11". We measure for the first time the unconfused phase-averaged X-ray spectrum of the 3.05-ms pulsar B1821-24 and find it is best described by a power law with photon index Gamma similar or equal to 1.2. We find marginal evidence of an emission line centered at 3.3 keV in the pulsar spectrum, which could be interpreted as cyclotron emission from a Corona above the pulsar's polar cap if the magnetic field is strongly different from a centered dipole. We present a spectral analyses of the brightest unidentified source and suggest that it is a transiently accreting neutron star in a low-mass X-ray binary, in quiescence. In addition to the resolved sources, we detect fainter, unresolved X-ray emission from the central core. C1 George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. USRA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. Penn State Univ, University Pk, PA 16802 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. European So Observ, D-85740 Garching, Germany. Univ Calif Berkeley, Berkeley, CA 94720 USA. Osserv Astron Roma, INAF, I-00040 Monte Porzio Catone, Italy. RP Weisskopf, MC (reprint author), George C Marshall Space Flight Ctr, Dept Space Sci, SD 50, Huntsville, AL 35812 USA. OI Pulone, Luigi/0000-0002-5285-998X; Testa, Vincenzo/0000-0003-1033-1340 NR 14 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUN PY 2004 VL 132 BP 566 EP 571 DI 10.1016/j.nuclphysbps.2004.04.095 PG 6 WC Physics, Particles & Fields SC Physics GA 845FX UT WOS:000223224300097 ER PT J AU Gogus, E Kouveliotou, C Woods, PM Finger, MH van der Klis, M AF Gogus, E Kouveliotou, C Woods, PM Finger, MH van der Klis, M TI Pulse profile evolution in SGR 1806-20 and SGR 1900+14 SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 2nd BeppoSAX Conference on Restless High-Engery Universe CY MAY 05-08, 2003 CL Amsterdam, NETHERLANDS SP Royal Netherlands Acad Arts & Sci, Acad Dei Lincei Rome AB Soft Gamma-ray Repeaters exhibit pulse profile changes in connection with their burst activity. We present the first detailed history of the pulse profile evolution of two SGRs using a large set of RXTE/PCA observations spanning similar to5 years, and we examine their evolution with energy. This study allows us to investigate the burst induced changes of the pulse profiles, and the pulsed count rates (proportional to the pulsed X-ray intensity) during the burst activity or in quiescence. C1 Sabanci Univ, FENS, TR-34956 Istanbul, Turkey. NASA, MSFC, Huntsville, AL 35812 USA. NSSTC, Huntsville, AL 35805 USA. Univ Amsterdam, NL-1098 SJ Amsterdam, Netherlands. RP Gogus, E (reprint author), Sabanci Univ, FENS, TR-34956 Istanbul, Turkey. NR 4 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUN PY 2004 VL 132 BP 604 EP 607 DI 10.1016/j.nuclphysbps.2004.04.103 PG 4 WC Physics, Particles & Fields SC Physics GA 845FX UT WOS:000223224300106 ER PT J AU Markwardt, CB AF Markwardt, CB CA Swift Team TI Monitoring and detecting X-ray transients with the Swift Observatory SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 2nd BeppoSAX Conference on Restless High-Energy Universe CY MAY 05-08, 2003 CL Amsterdam, NETHERLANDS SP Royal Netherlands Acad Arts & Sci, Acad Dei Lincei Rome ID AFTERGLOW; BURST; MIDEX AB Swift is a multi-wavelength observatory specifically designed to detect transient sources in the gamma-ray energy band 15-200 keV. The primary goals of the mission involve gamma ray burst (GRB) astronomy, namely to determine the origin of GRBs and their afterglows, and use bursts to probe the early Universe. However, Swift will also discover new X-ray transient sources, and it will be possible to bring Swift's considerable multi-wavelength capabilities to bear on these sources, and those discovered by other means. The Burst Alert Telescope (BAT) is a coded mask instrument sensitive to 15-200 keV gamma-rays, and has a field of view which covers approximately 1/8th of the sky in a single pointing. Over a typical observing day, almost the entire sky will be observed and monitored for new transient sources. Sources will be detected within several hours of observation. The two narrow field instruments, the X-ray Telescope and Ultra-Violet Optical Telescope, can provide sensitive simultaneous imaging and spectroscopy observations in the optical through soft X-ray bands. C1 Univ Maryland, College Pk, MD 20772 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Markwardt, CB (reprint author), Univ Maryland, College Pk, MD 20772 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUN PY 2004 VL 132 BP 689 EP 692 DI 10.1016/j.nuclphysbps.2004.04.122 PG 4 WC Physics, Particles & Fields SC Physics GA 845FX UT WOS:000223224300125 ER PT J AU de Martino, D Matt, G Belloni, T Chiappetti, L Haberl, F Mukai, K AF de Martino, D Matt, G Belloni, T Chiappetti, L Haberl, F Mukai, K TI The X-ray emission of Intermediate Polars: the BeppoSAX view and the role of current missions SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 2nd BeppoSAX Conference on Restless High-Engery Universe CY MAY 05-08, 2003 CL Amsterdam, NETHERLANDS SP Royal Netherlands Acad Arts & Sci, Acad Dei Lincei Rome ID CATACLYSMIC VARIABLES AB Intermediate Polars (IPs) are the most intriguing systems among Cataclysmic Variables (CVs), as the X-ray spectral and temporal behaviour is not similar in all members. The simultaneous study of broad-band X-ray temporal and spectral properties is crucial to characterize the accretion geometry and the physical conditions of the accretion flow onto moderately (B<10-20 MG) magnetized white dwarfs. Thanks to the wide energy coverage, BeppoSAX observations of bright IPs have allowed to infer the accretion mode, the presence of complex patchy absorption in the pre-shock flow and of a Compton reflection component from the white dwarf surface as well as to measure simultaneously the temperature of the post-shock region and that of the irradiated poles of the white dwarf atmosphere. The observations show that accretion in these systems cannot be reconciled with a single scenario, accounting for their soft and hard X-ray behaviour. Many known systems and IP candidates still lack of X-ray characterization in both soft and hard bands, for which current X-ray missions are providing new and unprecedented results. C1 INAF, Osservatorio Astron Capodimonte Napoli, I-80131 Naples, Italy. Univ Rome 3, Dipartimento Fis, I-00146 Rome, Italy. INAF, Osservatorio Astron Brera, I-23807 Merate, LC, Italy. CNR, IASF, INAF, I-20133 Milan, Italy. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP de Martino, D (reprint author), INAF, Osservatorio Astron Capodimonte Napoli, I-80131 Naples, Italy. OI Haberl, Frank/0000-0002-0107-5237; de Martino, Domitilla/0000-0002-5069-4202; Chiappetti, Lucio/0000-0001-7857-7908 NR 9 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUN PY 2004 VL 132 BP 693 EP 696 DI 10.1016/j.nuclphysbps.2004.04.123 PG 4 WC Physics, Particles & Fields SC Physics GA 845FX UT WOS:000223224300126 ER PT J AU Hong, J AF Hong, J TI Precision compensation for polarization anisotropies in metal reflectors SO OPTICAL ENGINEERING LA English DT Editorial Material DE optical compensation; metal reflector; polarization anisotropy AB It is known that the reflection at a dielectric/metal boundary exhibits anisotropy at nonzero incidence angles. This is of concern for high-performance reflecting telescopes where the low F# can lead to a non-negligible polarization dependent amplitude and phase apodization. After calculating the phase apodization as a function of incidence angle, we describe an effective compensation technique using form birefringence. (C) 2004 Society of Photo-Optical Instrumentation Engineers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hong, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM john.hong@jpl.nasa.gov NR 5 TC 1 Z9 2 U1 0 U2 1 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD JUN PY 2004 VL 43 IS 6 BP 1276 EP 1277 DI 10.1117/1.1695565 PG 2 WC Optics SC Optics GA 830AL UT WOS:000222093900003 ER PT J AU Smith, DD Chang, H Fuller, KA Rosenberger, AT Boyd, RW AF Smith, DD Chang, H Fuller, KA Rosenberger, AT Boyd, RW TI Coupled-resonator-induced transparency SO PHYSICAL REVIEW A LA English DT Article ID ELECTROMAGNETICALLY INDUCED TRANSPARENCY; QUANTUM INTERFERENCE; ABSORPTION; CAVITY AB We demonstrate that a cancellation of absorption occurs on resonance for two (or any even number of) coupled optical resonators, due to mode splitting and classical destructive interference, particularly when the resonator finesse is large and the loss in the resonator farthest from the excitation waveguide is small. The linewidth and group velocity of a collection of such coupled-resonator structures may be decreased by using larger resonators of equal size, by using larger resonators of unequal size where the optical path length of the larger resonator is an integer multiple of that of the smaller one, or by using a larger number of resonators per structure. We explore the analogy between these effects and electromagnetically-induced transparency in an atomic system. C1 NASA, George C Marshall Space Flight Ctr, Sci Directorate, Huntsville, AL 35812 USA. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. Univ Alabama, Dept Atmospher Sci, Natl Space Sci & Technol Ctr, Earth Sci Syst Grp, Huntsville, AL 35899 USA. Oklahoma State Univ, Dept Phys, Stillwater, OK 74078 USA. Univ Rochester, Inst Opt, Rochester, NY 14627 USA. RP Smith, DD (reprint author), NASA, George C Marshall Space Flight Ctr, Sci Directorate, Huntsville, AL 35812 USA. NR 22 TC 187 Z9 192 U1 4 U2 32 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 2004 VL 69 IS 6 AR 063804 DI 10.1103/PhysRevA.69.063804 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 835GT UT WOS:000222471400106 ER PT J AU Smits, CJP Filip, AT Swagten, HJM Koopmans, B de Jonge, WJM Chernyshova, M Kowalczyk, L Grasza, K Szczerbakow, A Story, T Palosz, W Sipatov, AY AF Smits, CJP Filip, AT Swagten, HJM Koopmans, B de Jonge, WJM Chernyshova, M Kowalczyk, L Grasza, K Szczerbakow, A Story, T Palosz, W Sipatov, AY TI Antiferromagnetic interlayer exchange coupling in all-semiconducting EuS/PbS/EuS trilayers SO PHYSICAL REVIEW B LA English DT Article ID EUS-PBS MULTILAYERS; MAGNETIC SEMICONDUCTORS; SUPERLATTICES; SPINTRONICS AB A comprehensive experimental study on the antiferromagnetic interlayer exchange coupling in high quality epitaxial all-semiconducting EuS/PbS/EuS trilayers is reported. The influence of substrates, of the thickness of the nonmagnetic PbS spacer layer, and of temperature was investigated by means of SQUID magnetometry. In trilayers with a PbS thickness between 4 and 12 A the low temperature hysteresis loops showed the signature of antiferromagnetic coupling. The value of the interlayer exchange coupling energy was determined by simulating the data based on a Stoner-Wohlfarth model. An important observation was that the interlayer exchange coupling energy varies strongly with temperature, consistent with a power-law dependence of the exchange coupling constant on the saturation magnetization of the EuS layers. While no theoretical description is readily available, we conjecture that the observed behavior is due to a dependence of the interlayer exchange coupling energy on the exchange splitting of the EuS bands. C1 Eindhoven Univ Technol, Ctr Nanomat, Dept Appl Phys, NL-5600 MB Eindhoven, Netherlands. Eindhoven Univ Technol, COBRA Res Inst, NL-5600 MB Eindhoven, Netherlands. Polish Acad Sci, Inst Phys, PL-02668 Warsaw, Poland. NASA, BAE, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Natl Tech Univ KPI, UA-61002 Kharkov, Ukraine. RP Smits, CJP (reprint author), Eindhoven Univ Technol, Ctr Nanomat, Dept Appl Phys, POB 513, NL-5600 MB Eindhoven, Netherlands. EM c.j.p.smits@tue.nl OI Sipatov, Alexander/0000-0002-2693-2135 NR 38 TC 19 Z9 19 U1 2 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD JUN PY 2004 VL 69 IS 22 AR 224410 DI 10.1103/PhysRevB.69.224410 PG 7 WC Physics, Condensed Matter SC Physics GA 836BU UT WOS:000222530900053 ER PT J AU Zhao, GL Bagayoko, D Yang, L AF Zhao, GL Bagayoko, D Yang, L TI Effective masses of charge carriers in selected symmorphic and nonsymmorphic carbon nanotubes SO PHYSICAL REVIEW B LA English DT Article ID INHOMOGENEOUS ELECTRON-GAS; AB-INITIO; APPROXIMATION; 1ST-PRINCIPLES; CONDUCTANCE; JUNCTIONS; GRAPHENE; TUBULES; STATES; ENERGY AB We performed ab initio, self-consistent calculations for the electronic structure of selected semiconducting carbon nanotubes in the symmorphic and nonsymmorphic groups. We employed a real space approach in the linear combination of atomic orbital formalism. We utilized a nonlocal density-functional potential in the generalized gradient approximation. We present the electronic structure and effective masses of charge carriers in symmorphic nanotubes that include (10,0), (13,0), (17,0), and (22,0), and the nonsymmorphic tubes (8,4) and (10,5). For nonsymmorphic carbon nanotubes (8,4) and (10,5), the top of the highest occupied valence band and the bottom of the lowest unoccupied conduction band are not at the Gamma point, but at about +/-0.1(1,0,0)pi/L, where the tubule axis is defined as the (1,0,0) direction. The band gaps in the nonsymmorphic (8,4) and (10,5) can be direct for transitions at +0.1(1,0,0)pi/L or -0.1(1,0,0)pi/L, and can also be indirect for transitions from +0.1(1,0,0)pi/L to -0.1(1,0,0)pi/L, or vice versa. C1 Southern Univ, Dept Phys, Baton Rouge, LA 70813 USA. A&M Coll, Baton Rouge, LA 70813 USA. NASA, Ames Res Ctr, Elotet, Moffett Field, CA 94035 USA. RP Southern Univ, Dept Phys, Baton Rouge, LA 70813 USA. EM zhao@grant.phys.subr.edu NR 44 TC 26 Z9 26 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD JUN PY 2004 VL 69 IS 24 AR 245416 DI 10.1103/PhysRevB.69.245416 PG 7 WC Physics, Condensed Matter SC Physics GA 836CC UT WOS:000222531800088 ER PT J AU Abbott, B Abbott, R Adhikari, R Ageev, A Allen, B Amin, R Anderson, SB Anderson, WG Araya, M Armandula, H Asiri, F Aufmuth, P Aulbert, C Babak, S Balasubramanian, R Ballmer, S Barish, BC Barker, D Barker-Patton, C Barnes, M Barr, B Barton, MA Bayer, K Beausoleil, R Belczynski, K Bennett, R Berukoff, SJ Betzwieser, J Bhawal, B Bilenko, IA Billingsley, G Black, E Blackburn, K Bland-Weaver, B Bochner, B Bogue, L Bork, R Bose, S Brady, PR Braginsky, VB Brau, JE Brown, DA Brozek, S Bullington, A Buonanno, A Burgess, R Busby, D Butler, WE Byer, RL Cadonati, L Cagnoli, G Camp, JB Cantley, CA Cardenas, L Carter, K Casey, MM Castiglione, J Chandler, A Chapsky, J Charlton, P Chatterji, S Chen, Y Chickarmane, V Chin, D Christensen, N Churches, D Colacino, C Coldwell, R Coles, M Cook, D Corbitt, T Coyne, D Creighton, JDE Creighton, TD Crooks, DRM Csatorday, P Cusack, BJ Cutler, C D'Ambrosio, E Danzmann, K Davies, R Daw, E DeBra, D Delker, T DeSalvo, R Dhurandhar, S Diaz, M Ding, H Drever, RWP Dupuis, RJ Ebeling, C Edlund, J Ehrens, P Elliffe, EJ Etzel, T Evans, M Evans, T Fallnich, C Farnham, D Fejer, MM Fine, M Finn, LS Flanagan, E Freise, A Frey, R Fritschel, P Frolov, V Fyffe, M Ganezer, KS Giaime, JA Gillespie, A Goda, K Gonzalez, G Gossler, S Grandclement, P Grant, A Gray, C Gretarsson, AM Grimmett, D Grote, H Grunewald, S Guenther, M Gustafson, E Gustafson, R Hamilton, WO Hammond, M Hanson, J Hardham, C Harry, G Hartunian, A Heefner, J Hefetz, Y Heinzel, G Heng, IS Hennessy, M Hepler, N Heptonstall, A Heurs, M Hewitson, M Hindman, N Hoang, P Hough, J Hrynevych, M Hua, W Ingley, R Ito, M Itoh, Y Ivanov, A Jennrich, O Johnson, WW Johnston, W Jones, L Jungwirth, D Kalogera, V Katsavounidis, E Kawabe, K Kawamura, S Kells, W Kern, J Khan, A Killbourn, S Killow, CJ Kim, C King, C King, P Klimenko, S Kloevekorn, P Koranda, S Kotter, K Kovalik, J Kozak, D Krishnan, B Landry, M Langdale, J Lantz, B Lawrence, R Lazzarini, A Lei, M Leonhardt, V Leonor, I Libbrecht, K Lindquist, P Liu, S Logan, J Lormand, M Lubinski, M Luck, H Lyons, TT Machenschalk, B MacInnis, M Mageswaran, M Mailand, K Majid, W Malec, M Mann, F Marin, A Marka, S Maros, E Mason, J Mason, K Matherny, O Matone, L Mavalvala, N McCarthy, R McClelland, DE McHugh, M McNamara, P Mendell, G Meshkov, S Messenger, C Mitrofanov, VP Mitselmakher, G Mittleman, R Miyakawa, O Miyoki, S Mohanty, S Moreno, G Mossavi, K Mours, B Mueller, G Mukherjee, S Myers, J Nagano, S Nash, T Naundorf, H Nayak, R Newton, G Nocera, F Nutzman, P Olson, T O'Reilly, B Ottaway, DJ Ottewill, A Ouimette, D Overmier, H Owen, BJ Papa, MA Parameswariah, C Parameswariah, V Pedraza, M Penn, S Pitkin, M Plissi, M Pratt, M Quetschke, V Raab, F Radkins, H Rahkola, R Rakhmanov, M Rao, SR Redding, D Regehr, MW Regimbau, T Reilly, KT Reithmaier, K Reitze, DH Richman, S Riesen, R Riles, K Rizzi, A Robertson, DI Robertson, NA Robison, L Roddy, S Rollins, J Romano, JD Romie, J Rong, H Rose, D Rotthoff, E Rowan, S Rudiger, A Russell, P Ryan, K Salzman, I Sanders, GH Sannibale, V Sathyaprakash, B Saulson, PR Savage, R Sazonov, A Schilling, R Schlaufman, K Schmidt, V Schofield, R Schrempel, M Schutz, BF Schwinberg, P Scott, SM Searle, AC Sears, B Seel, S Sengupta, AS Shapiro, CA Shawhan, P Shoemaker, DH Shu, QZ Sibley, A Siemens, X Sievers, L Sigg, D Sintes, AM Skeldon, K Smith, JR Smith, M Smith, MR Sneddon, P Spero, R Stapfer, G Strain, KA Strom, D Stuver, A Summerscales, T Sumner, MC Sutton, PJ Sylvestre, J Takamori, A Tanner, DB Tariq, H Taylor, I Taylor, R Thorne, KS Tibbits, M Tilav, S Tinto, M Tokmakov, KV Torres, C Torrie, C Traeger, S Traylor, G Tyler, W Ugolini, D Vallisneri, M van Putten, M Vass, S Vecchio, A Vorvick, C Vyachanin, SP Wallace, L Walther, H Ward, H Ware, B Watts, K Webber, D Weidner, A Weiland, U Weinstein, A Weiss, R Welling, H Wen, L Wen, S Whelan, JT Whitcomb, SE Whiting, BF Willems, PA Williams, PR Williams, R Willke, B Wilson, A Winjum, BJ Winkler, W Wise, S Wiseman, AG Woan, G Wooley, R Worden, J Yakushin, I Yamamoto, H Yoshida, S Zawischa, I Zhang, L Zotov, N Zucker, M Zweizig, J AF Abbott, B Abbott, R Adhikari, R Ageev, A Allen, B Amin, R Anderson, SB Anderson, WG Araya, M Armandula, H Asiri, F Aufmuth, P Aulbert, C Babak, S Balasubramanian, R Ballmer, S Barish, BC Barker, D Barker-Patton, C Barnes, M Barr, B Barton, MA Bayer, K Beausoleil, R Belczynski, K Bennett, R Berukoff, SJ Betzwieser, J Bhawal, B Bilenko, IA Billingsley, G Black, E Blackburn, K Bland-Weaver, B Bochner, B Bogue, L Bork, R Bose, S Brady, PR Braginsky, VB Brau, JE Brown, DA Brozek, S Bullington, A Buonanno, A Burgess, R Busby, D Butler, WE Byer, RL Cadonati, L Cagnoli, G Camp, JB Cantley, CA Cardenas, L Carter, K Casey, MM Castiglione, J Chandler, A Chapsky, J Charlton, P Chatterji, S Chen, Y Chickarmane, V Chin, D Christensen, N Churches, D Colacino, C Coldwell, R Coles, M Cook, D Corbitt, T Coyne, D Creighton, JDE Creighton, TD Crooks, DRM Csatorday, P Cusack, BJ Cutler, C D'Ambrosio, E Danzmann, K Davies, R Daw, E DeBra, D Delker, T DeSalvo, R Dhurandhar, S Diaz, M Ding, H Drever, RWP Dupuis, RJ Ebeling, C Edlund, J Ehrens, P Elliffe, EJ Etzel, T Evans, M Evans, T Fallnich, C Farnham, D Fejer, MM Fine, M Finn, LS Flanagan, E Freise, A Frey, R Fritschel, P Frolov, V Fyffe, M Ganezer, KS Giaime, JA Gillespie, A Goda, K Gonzalez, G Gossler, S Grandclement, P Grant, A Gray, C Gretarsson, AM Grimmett, D Grote, H Grunewald, S Guenther, M Gustafson, E Gustafson, R Hamilton, WO Hammond, M Hanson, J Hardham, C Harry, G Hartunian, A Heefner, J Hefetz, Y Heinzel, G Heng, IS Hennessy, M Hepler, N Heptonstall, A Heurs, M Hewitson, M Hindman, N Hoang, P Hough, J Hrynevych, M Hua, W Ingley, R Ito, M Itoh, Y Ivanov, A Jennrich, O Johnson, WW Johnston, W Jones, L Jungwirth, D Kalogera, V Katsavounidis, E Kawabe, K Kawamura, S Kells, W Kern, J Khan, A Killbourn, S Killow, CJ Kim, C King, C King, P Klimenko, S Kloevekorn, P Koranda, S Kotter, K Kovalik, J Kozak, D Krishnan, B Landry, M Langdale, J Lantz, B Lawrence, R Lazzarini, A Lei, M Leonhardt, V Leonor, I Libbrecht, K Lindquist, P Liu, S Logan, J Lormand, M Lubinski, M Luck, H Lyons, TT Machenschalk, B MacInnis, M Mageswaran, M Mailand, K Majid, W Malec, M Mann, F Marin, A Marka, S Maros, E Mason, J Mason, K Matherny, O Matone, L Mavalvala, N McCarthy, R McClelland, DE McHugh, M McNamara, P Mendell, G Meshkov, S Messenger, C Mitrofanov, VP Mitselmakher, G Mittleman, R Miyakawa, O Miyoki, S Mohanty, S Moreno, G Mossavi, K Mours, B Mueller, G Mukherjee, S Myers, J Nagano, S Nash, T Naundorf, H Nayak, R Newton, G Nocera, F Nutzman, P Olson, T O'Reilly, B Ottaway, DJ Ottewill, A Ouimette, D Overmier, H Owen, BJ Papa, MA Parameswariah, C Parameswariah, V Pedraza, M Penn, S Pitkin, M Plissi, M Pratt, M Quetschke, V Raab, F Radkins, H Rahkola, R Rakhmanov, M Rao, SR Redding, D Regehr, MW Regimbau, T Reilly, KT Reithmaier, K Reitze, DH Richman, S Riesen, R Riles, K Rizzi, A Robertson, DI Robertson, NA Robison, L Roddy, S Rollins, J Romano, JD Romie, J Rong, H Rose, D Rotthoff, E Rowan, S Rudiger, A Russell, P Ryan, K Salzman, I Sanders, GH Sannibale, V Sathyaprakash, B Saulson, PR Savage, R Sazonov, A Schilling, R Schlaufman, K Schmidt, V Schofield, R Schrempel, M Schutz, BF Schwinberg, P Scott, SM Searle, AC Sears, B Seel, S Sengupta, AS Shapiro, CA Shawhan, P Shoemaker, DH Shu, QZ Sibley, A Siemens, X Sievers, L Sigg, D Sintes, AM Skeldon, K Smith, JR Smith, M Smith, MR Sneddon, P Spero, R Stapfer, G Strain, KA Strom, D Stuver, A Summerscales, T Sumner, MC Sutton, PJ Sylvestre, J Takamori, A Tanner, DB Tariq, H Taylor, I Taylor, R Thorne, KS Tibbits, M Tilav, S Tinto, M Tokmakov, KV Torres, C Torrie, C Traeger, S Traylor, G Tyler, W Ugolini, D Vallisneri, M van Putten, M Vass, S Vecchio, A Vorvick, C Vyachanin, SP Wallace, L Walther, H Ward, H Ware, B Watts, K Webber, D Weidner, A Weiland, U Weinstein, A Weiss, R Welling, H Wen, L Wen, S Whelan, JT Whitcomb, SE Whiting, BF Willems, PA Williams, PR Williams, R Willke, B Wilson, A Winjum, BJ Winkler, W Wise, S Wiseman, AG Woan, G Wooley, R Worden, J Yakushin, I Yamamoto, H Yoshida, S Zawischa, I Zhang, L Zotov, N Zucker, M Zweizig, J CA LIGO Sci Collaboration TI Analysis of first LIGO science data for stochastic gravitational waves SO PHYSICAL REVIEW D LA English DT Article ID UPPER LIMIT; DETECTOR; INTERFEROMETER; RADIATION; LASER AB We present the analysis of between 50 and 100 h of coincident interferometric strain data used to search for and establish an upper limit on a stochastic background of gravitational radiation. These data come from the first LIGO science run, during which all three LIGO interferometers were operated over a 2-week period spanning August and September of 2002. The method of cross correlating the outputs of two interferometers is used for analysis. We describe in detail practical signal processing issues that arise when working with real data, and we establish an observational upper limit on a f(-3) power spectrum of gravitational waves. Our 90% confidence limit is Omega(0)h(100)(2)less than or equal to23+/-4.6 in the frequency band 40-314 Hz, where h(100) is the Hubble constant in units of 100 km/sec/Mpc and Omega(0) is the gravitational wave energy density per logarithmic frequency interval in units of the closure density. This limit is approximately 10(4) times better than the previous, broadband direct limit using interferometric detectors, and nearly 3 times better than the best narrow-band bar detector limit. As LIGO and other worldwide detectors improve in sensitivity and attain their design goals, the analysis procedures described here should lead to stochastic background sensitivity levels of astrophysical interest. C1 CALTECH, LIGO, Pasadena, CA 91125 USA. Max Planck Inst Gravitat Phys, Albert Einstein Inst, D-14476 Golm, Germany. Max Planck Inst Gravitat Phys, Albert Einstein Inst, D-30167 Hannover, Germany. Australian Natl Univ, Canberra, ACT 0200, Australia. Calif State Univ Dominguez Hills, Carson, CA 90747 USA. CALTECH, CaRT, Pasadena, CA 91125 USA. Cardiff Univ, Cardiff CF2 3YB, S Glam, Wales. Carleton Coll, Northfield, MN 55057 USA. Cornell Univ, Ithaca, NY 14853 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Hobart & William Smith Coll, Geneva, NY 14456 USA. InterUniv Ctr Astron & Astrophys, Pune 411007, Maharashtra, India. MIT, LIGO, Cambridge, MA 02139 USA. LIGO Hanford Observ, Richland, WA 99352 USA. LIGO Livingston Observ, Livingston, LA 70754 USA. Louisiana State Univ, Baton Rouge, LA 70803 USA. Louisiana Tech Univ, Ruston, LA 71272 USA. Loyola Univ, New Orleans, LA 70118 USA. Max Planck Inst Quantum Opt, D-85748 Garching, Germany. Moscow MV Lomonosov State Univ, Moscow 119992, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Astron Observ Japan, Tokyo 1818588, Japan. Northwestern Univ, Evanston, IL 60208 USA. Salish Kootenai Coll, Pablo, MT 59855 USA. SE Louisiana Univ, Hammond, LA 70402 USA. Stanford Univ, Stanford, CA 94305 USA. Syracuse Univ, Syracuse, NY 13244 USA. Penn State Univ, University Pk, PA 16802 USA. Univ Texas, Brownsville, TX 78520 USA. Texas Southmost Coll, Brownsville, TX 78520 USA. Trinity Univ, San Antonio, TX 78212 USA. Leibniz Univ Hannover, D-30167 Hannover, Germany. Univ Illes Balears, E-07071 Palma de Mallorca, Spain. Univ Birmingham, Birmingham B15 2TT, W Midlands, England. Univ Florida, Gainesville, FL 32611 USA. Univ Glasgow, Glasgow G12 8QQ, Lanark, Scotland. Univ Michigan, Ann Arbor, MI 48109 USA. Univ Oregon, Eugene, OR 97403 USA. Univ Rochester, Rochester, NY 14627 USA. Univ Wisconsin, Milwaukee, WI 53201 USA. Washington State Univ, Pullman, WA 99164 USA. HP Labs, Palo Alto, CA USA. CNRS, Inst Astrophys Paris, GReCO, F-75700 Paris, France. Univ Tokyo, Inst Cosm Ray Res, Tokyo, Japan. Univ Coll Dublin, Dublin 2, Ireland. RP CALTECH, LIGO, Pasadena, CA 91125 USA. RI Frey, Raymond/E-2830-2016; Pitkin, Matthew/I-3802-2013; Vyatchanin, Sergey/J-2238-2012; Chen, Yanbei/A-2604-2013; Bilenko, Igor/D-5172-2012; Sylvestre, Julien/A-8610-2009; Casey, Morag/C-9703-2010; Raab, Frederick/E-2222-2011; Rowan, Sheila/E-3032-2010; Lueck, Harald/F-7100-2011; Freise, Andreas/F-8892-2011; Kawabe, Keita/G-9840-2011; Ottewill, Adrian/A-1838-2016; Sigg, Daniel/I-4308-2015; van Putten, Maurice/F-5237-2011; Beausoleil, Raymond/C-5076-2009; Allen, Bruce/K-2327-2012; McClelland, David/E-6765-2010; Vecchio, Alberto/F-8310-2015; Strain, Kenneth/D-5236-2011; Ottaway, David/J-5908-2015; Barker, David/A-5671-2013; Mitrofanov, Valery/D-8501-2012; Finn, Lee Samuel/A-3452-2009; Liu, Sheng/K-2815-2013; Schutz, Bernard/B-1504-2010; OI Frey, Raymond/0000-0003-0341-2636; Whelan, John/0000-0001-5710-6576; Stuver, Amber/0000-0003-0324-5735; O'Shaughnessy, Richard/0000-0001-5832-8517; Taylor, Ian/0000-0001-5040-0772; Zweizig, John/0000-0002-1521-3397; Aulbert, Carsten/0000-0002-1481-8319; Pitkin, Matthew/0000-0003-4548-526X; Sylvestre, Julien/0000-0001-8136-4348; Lueck, Harald/0000-0001-9350-4846; Ottewill, Adrian/0000-0003-3293-8450; Sigg, Daniel/0000-0003-4606-6526; Allen, Bruce/0000-0003-4285-6256; McClelland, David/0000-0001-6210-5842; Vecchio, Alberto/0000-0002-6254-1617; Strain, Kenneth/0000-0002-2066-5355; Finn, Lee Samuel/0000-0002-3937-0688; Heurs, Michele/0000-0002-5577-2273; Freise, Andreas/0000-0001-6586-9901; Tokmakov, Kirill/0000-0002-2808-6593; Whiting, Bernard F/0000-0002-8501-8669; Papa, M.Alessandra/0000-0002-1007-5298 NR 41 TC 163 Z9 163 U1 0 U2 9 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD JUN PY 2004 VL 69 IS 12 AR 122004 DI 10.1103/PhysRevD.69.122004 PG 24 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 838AA UT WOS:000222681600005 ER PT J AU Abbott, B Abbott, R Adhikari, R Ageev, A Allen, B Amin, R Anderson, SB Anderson, WG Araya, M Armandula, H Asiri, F Aufmuth, P Aulbert, C Babak, S Balasubramanian, R Ballmer, S Barish, BC Barker, D Barker-Patton, C Barnes, M Barr, B Barton, MA Bayer, K Beausoleil, R Belczynski, K Bennett, R Berukoff, SJ Betzwieser, J Bhawal, B Bilenko, IA Billingsley, G Black, E Blackburn, K Bland-Weaver, B Bochner, B Bogue, L Bork, R Bose, S Brady, PR Braginsky, VB Brau, JE Brown, DA Brozek, S Bullington, A Buonanno, A Burgess, R Busby, D Butler, WE Byer, RL Cadonati, L Cagnoli, G Camp, JB Cantley, CA Cardenas, L Carter, K Casey, MM Castiglione, J Chandler, A Chapsky, J Charlton, P Chatterji, S Chen, Y Chickarmane, V Chin, D Christensen, N Churches, D Colacino, C Coldwell, R Coles, M Cook, D Corbitt, T Coyne, D Creighton, JDE Creighton, TD Crooks, DRM Csatorday, P Cusack, BJ Cutler, C D'Ambrosio, E Danzmann, K Davies, R Daw, E DeBra, D Delker, T DeSalvo, R Dhurandhar, S Diaz, M Ding, H Drever, RWP Dupuis, RJ Ebeling, C Edlund, J Ehrens, P Elliffe, EJ Etzel, T Evans, M Evans, T Fallnich, C Farnham, D Fejer, MM Fine, M Finn, LS Flanagan, E Freise, A Frey, R Fritschel, P Frolov, V Fyffe, M Ganezer, KS Giaime, JA Gillespie, A Goda, K Gonzalez, G Gossler, S Grandclement, P Grant, A Gray, C Gretarsson, AM Grimmett, D Grote, H Grunewald, S Guenther, M Gustafson, E Gustafson, R Hamilton, WO Hammond, M Hanson, J Hardham, C Harry, G Hartunian, A Heefner, J Hefetz, Y Heinzel, G Heng, IS Hennessy, M Hepler, N Heptonstall, A Heurs, M Hewitson, M Hindman, N Hoang, P Hough, J Hrynevych, M Hua, W Ingley, R Ito, M Itoh, Y Ivanov, A Jennrich, O Johnson, WW Johnston, W Jones, L Jungwirth, D Kalogera, V Katsavounidis, E Kawabe, K Kawamura, S Kells, W Kern, J Khan, A Killbourn, S Killow, CJ Kim, C King, C King, P Klimenko, S Kloevekorn, P Koranda, S Kotter, K Kovalik, J Kozak, D Krishnan, B Landry, M Langdale, J Lantz, B Lawrence, R Lazzarini, A Lei, M Leonhardt, V Leonor, I Libbrecht, K Lindquist, P Liu, S Logan, J Lormand, M Lubinski, M Luck, H Lyons, TT Machenschalk, B MacInnis, M Mageswaran, M Mailand, K Majid, W Malec, M Mann, F Marin, A Marka, S Maros, E Mason, J Mason, K Matherny, O Matone, L Mavalvala, N McCarthy, R McClelland, DE McHugh, M McNamara, P Mendell, G Meshkov, S Messenger, C Mitrofanov, VP Mitselmakher, G Mittleman, R Miyakawa, O Miyoki, S Mohanty, S Moreno, G Mossavi, K Mours, B Mueller, G Mukherjee, S Myers, J Nagano, S Nash, T Naundorf, H Nayak, R Newton, G Nocera, F Nutzman, P Olson, T O'Reilly, B Ottaway, DJ Ottewill, A Ouimette, D Overmier, H Owen, BJ Papa, MA Parameswariah, C Parameswariah, V Pedraza, M Penn, S Pitkin, M Plissi, M Pratt, M Quetschke, V Raab, F Radkins, H Rahkola, R Rakhmanov, M Rao, SR Redding, D Regehr, MW Regimbau, T Reilly, KT Reithmaier, K Reitze, DH Richman, S Riesen, R Riles, K Rizzi, A Robertson, DI Robertson, NA Robison, L Roddy, S Rollins, J Romano, JD Romie, J Rong, H Rose, D Rotthoff, E Rowan, S Rudiger, A Russell, P Ryan, K Salzman, I Sanders, GH Sannibale, V Sathyaprakash, B Saulson, PR Savage, R Sazonov, A Schilling, R Schlaufman, K Schmidt, V Schofield, R Schrempel, M Schutz, BF Schwinberg, P Scott, SM Searle, AC Sears, B Seel, S Sengupta, AS Shapiro, CA Shawhan, P Shoemaker, DH Shu, QZ Sibley, A Siemens, X Sievers, L Sigg, D Sintes, AM Skeldon, K Smith, JR Smith, M Smith, MR Sneddon, P Spero, R Stapfer, G Strain, KA Strom, D Stuver, A Summerscales, T Sumner, MC Sutton, PJ Sylvestre, J Takamori, A Tanner, DB Tariq, H Taylor, I Taylor, R Thorne, KS Tibbits, M Tilav, S Tinto, M Tokmakov, KV Torres, C Torrie, C Traeger, S Traylor, G Tyler, W Ugolini, D Vallisneri, M van Putten, M Vass, S Vecchio, A Vorvick, C Vyachanin, SP Wallace, L Walther, H Ward, H Ware, B Watts, K Webber, D Weidner, A Weiland, U Weinstein, A Weiss, R Welling, H Wen, L Wen, S Whelan, JT Whitcomb, SE Whiting, BF Willems, PA Williams, PR Williams, R Willke, B Wilson, A Winjum, BJ Winkler, W Wise, S Wiseman, AG Woan, G Wooley, R Worden, J Yakushin, I Yamamoto, H Yoshida, S Zawischa, I Zhang, L Zotov, N Zucker, M Zweizig, J AF Abbott, B Abbott, R Adhikari, R Ageev, A Allen, B Amin, R Anderson, SB Anderson, WG Araya, M Armandula, H Asiri, F Aufmuth, P Aulbert, C Babak, S Balasubramanian, R Ballmer, S Barish, BC Barker, D Barker-Patton, C Barnes, M Barr, B Barton, MA Bayer, K Beausoleil, R Belczynski, K Bennett, R Berukoff, SJ Betzwieser, J Bhawal, B Bilenko, IA Billingsley, G Black, E Blackburn, K Bland-Weaver, B Bochner, B Bogue, L Bork, R Bose, S Brady, PR Braginsky, VB Brau, JE Brown, DA Brozek, S Bullington, A Buonanno, A Burgess, R Busby, D Butler, WE Byer, RL Cadonati, L Cagnoli, G Camp, JB Cantley, CA Cardenas, L Carter, K Casey, MM Castiglione, J Chandler, A Chapsky, J Charlton, P Chatterji, S Chen, Y Chickarmane, V Chin, D Christensen, N Churches, D Colacino, C Coldwell, R Coles, M Cook, D Corbitt, T Coyne, D Creighton, JDE Creighton, TD Crooks, DRM Csatorday, P Cusack, BJ Cutler, C D'Ambrosio, E Danzmann, K Davies, R Daw, E DeBra, D Delker, T DeSalvo, R Dhurandhar, S Diaz, M Ding, H Drever, RWP Dupuis, RJ Ebeling, C Edlund, J Ehrens, P Elliffe, EJ Etzel, T Evans, M Evans, T Fallnich, C Farnham, D Fejer, MM Fine, M Finn, LS Flanagan, E Freise, A Frey, R Fritschel, P Frolov, V Fyffe, M Ganezer, KS Giaime, JA Gillespie, A Goda, K Gonzalez, G Gossler, S Grandclement, P Grant, A Gray, C Gretarsson, AM Grimmett, D Grote, H Grunewald, S Guenther, M Gustafson, E Gustafson, R Hamilton, WO Hammond, M Hanson, J Hardham, C Harry, G Hartunian, A Heefner, J Hefetz, Y Heinzel, G Heng, IS Hennessy, M Hepler, N Heptonstall, A Heurs, M Hewitson, M Hindman, N Hoang, P Hough, J Hrynevych, M Hua, W Ingley, R Ito, M Itoh, Y Ivanov, A Jennrich, O Johnson, WW Johnston, W Jones, L Jungwirth, D Kalogera, V Katsavounidis, E Kawabe, K Kawamura, S Kells, W Kern, J Khan, A Killbourn, S Killow, CJ Kim, C King, C King, P Klimenko, S Kloevekorn, P Koranda, S Kotter, K Kovalik, J Kozak, D Krishnan, B Landry, M Langdale, J Lantz, B Lawrence, R Lazzarini, A Lei, M Leonhardt, V Leonor, I Libbrecht, K Lindquist, P Liu, S Logan, J Lormand, M Lubinski, M Luck, H Lyons, TT Machenschalk, B MacInnis, M Mageswaran, M Mailand, K Majid, W Malec, M Mann, F Marin, A Marka, S Maros, E Mason, J Mason, K Matherny, O Matone, L Mavalvala, N McCarthy, R McClelland, DE McHugh, M McNamara, P Mendell, G Meshkov, S Messenger, C Mitrofanov, VP Mitselmakher, G Mittleman, R Miyakawa, O Miyoki, S Mohanty, S Moreno, G Mossavi, K Mours, B Mueller, G Mukherjee, S Myers, J Nagano, S Nash, T Naundorf, H Nayak, R Newton, G Nocera, F Nutzman, P Olson, T O'Reilly, B Ottaway, DJ Ottewill, A Ouimette, D Overmier, H Owen, BJ Papa, MA Parameswariah, C Parameswariah, V Pedraza, M Penn, S Pitkin, M Plissi, M Pratt, M Quetschke, V Raab, F Radkins, H Rahkola, R Rakhmanov, M Rao, SR Redding, D Regehr, MW Regimbau, T Reilly, KT Reithmaier, K Reitze, DH Richman, S Riesen, R Riles, K Rizzi, A Robertson, DI Robertson, NA Robison, L Roddy, S Rollins, J Romano, JD Romie, J Rong, H Rose, D Rotthoff, E Rowan, S Rudiger, A Russell, P Ryan, K Salzman, I Sanders, GH Sannibale, V Sathyaprakash, B Saulson, PR Savage, R Sazonov, A Schilling, R Schlaufman, K Schmidt, V Schofield, R Schrempel, M Schutz, BF Schwinberg, P Scott, SM Searle, AC Sears, B Seel, S Sengupta, AS Shapiro, CA Shawhan, P Shoemaker, DH Shu, QZ Sibley, A Siemens, X Sievers, L Sigg, D Sintes, AM Skeldon, K Smith, JR Smith, M Smith, MR Sneddon, P Spero, R Stapfer, G Strain, KA Strom, D Stuver, A Summerscales, T Sumner, MC Sutton, PJ Sylvestre, J Takamori, A Tanner, DB Tariq, H Taylor, I Taylor, R Thorne, KS Tibbits, M Tilav, S Tinto, M Tokmakov, KV Torres, C Torrie, C Traeger, S Traylor, G Tyler, W Ugolini, D Vallisneri, M van Putten, M Vass, S Vecchio, A Vorvick, C Vyachanin, SP Wallace, L Walther, H Ward, H Ware, B Watts, K Webber, D Weidner, A Weiland, U Weinstein, A Weiss, R Welling, H Wen, L Wen, S Whelan, JT Whitcomb, SE Whiting, BF Willems, PA Williams, PR Williams, R Willke, B Wilson, A Winjum, BJ Winkler, W Wise, S Wiseman, AG Woan, G Wooley, R Worden, J Yakushin, I Yamamoto, H Yoshida, S Zawischa, I Zhang, L Zotov, N Zucker, M Zweizig, J CA LIGO Sci Collaboration TI Analysis of LIGO data for gravitational waves from binary neutron stars SO PHYSICAL REVIEW D LA English DT Article ID INSPIRALING COMPACT BINARIES; RELATIVISTIC GRAVITY; COALESCENCE RATES; SEARCH TEMPLATES; DETECTORS; PULSAR; INTERFEROMETER; SYSTEMS; FORMS; LASER AB We report on a search for gravitational waves from coalescing compact binary systems in the Milky Way and the Magellanic Clouds. The analysis uses data taken by two of the three LIGO interferometers during the first LIGO science run and illustrates a method of setting upper limits on inspiral event rates using interferometer data. The analysis pipeline is described with particular attention to data selection and coincidence between the two interferometers. We establish an observational upper limit of R<1.7x10(2) per year per Milky Way Equivalent Galaxy (MWEG), with 90% confidence, on the coalescence rate of binary systems in which each component has a mass in the range 1-3 M. C1 CALTECH, LIGO, Pasadena, CA 91125 USA. Max Planck Inst Gravitat Phys, Albert Einstein Inst, D-14476 Golm, Germany. Max Planck Inst Gravitat Phys, Albert Einstein Inst, D-30167 Hannover, Germany. Australian Natl Univ, Canberra, ACT 0200, Australia. Calif State Univ Dominguez Hills, Carson, CA 90747 USA. CALTECH, CaRT, Pasadena, CA 91125 USA. Cardiff Univ, Cardiff CF2 3YB, S Glam, Wales. Carleton Coll, Northfield, MN 55057 USA. Cornell Univ, Ithaca, NY 14853 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Hobart & William Smith Coll, Geneva, NY 14456 USA. InterUniv Ctr Astron & Astrophys, Pune 411007, Maharashtra, India. MIT, LIGO, Cambridge, MA 02139 USA. LIGO Hanford Observ, Richland, WA 99352 USA. LIGO Livingston Observ, Livingston, LA 70754 USA. Louisiana State Univ, Baton Rouge, LA 70803 USA. Louisiana Tech Univ, Ruston, LA 71272 USA. Loyola Univ, New Orleans, LA 70118 USA. Max Planck Inst Quantum Opt, D-85748 Garching, Germany. Moscow MV Lomonosov State Univ, Moscow 119992, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Astron Observ Japan, Tokyo 1818588, Japan. Northwestern Univ, Evanston, IL 60208 USA. Salish Kootenai Coll, Pablo, MT 59855 USA. SE Louisiana Univ, Hammond, LA 70402 USA. Stanford Univ, Stanford, CA 94305 USA. Syracuse Univ, Syracuse, NY 13244 USA. Penn State Univ, University Pk, PA 16802 USA. Univ Texas, Brownsville, TX 78520 USA. Texas Southmost Coll, Brownsville, TX 78520 USA. Trinity Univ, San Antonio, TX 78212 USA. Leibniz Univ Hannover, D-30167 Hannover, Germany. Univ Illes Balears, E-07071 Palma de Mallorca, Spain. Univ Birmingham, Birmingham B15 2TT, W Midlands, England. Univ Florida, Gainesville, FL 32611 USA. Univ Glasgow, Glasgow G12 8QQ, Lanark, Scotland. Univ Michigan, Ann Arbor, MI 48109 USA. Univ Oregon, Eugene, OR 97403 USA. Univ Rochester, Rochester, NY 14627 USA. Univ Wisconsin, Milwaukee, WI 53201 USA. Washington State Univ, Pullman, WA 99164 USA. HP Labs, Palo Alto, CA USA. CNRS, Inst Astrophys Paris, GReCO, F-75700 Paris, France. Univ Tokyo, Inst Cosm Ray Res, Tokyo, Japan. Univ Coll Dublin, Dublin 2, Ireland. NASA, Jet Prop Lab, Pasadena, CA USA. RP CALTECH, LIGO, Pasadena, CA 91125 USA. RI Barker, David/A-5671-2013; Liu, Sheng/K-2815-2013; Vecchio, Alberto/F-8310-2015; Finn, Lee Samuel/A-3452-2009; Ottaway, David/J-5908-2015; Ottewill, Adrian/A-1838-2016; Sigg, Daniel/I-4308-2015; Frey, Raymond/E-2830-2016; Beausoleil, Raymond/C-5076-2009; McClelland, David/E-6765-2010; Kawabe, Keita/G-9840-2011; Lueck, Harald/F-7100-2011; Strain, Kenneth/D-5236-2011; Bilenko, Igor/D-5172-2012; Freise, Andreas/F-8892-2011; Mitrofanov, Valery/D-8501-2012; van Putten, Maurice/F-5237-2011; Pitkin, Matthew/I-3802-2013; Allen, Bruce/K-2327-2012; Vyatchanin, Sergey/J-2238-2012; Chen, Yanbei/A-2604-2013; Sylvestre, Julien/A-8610-2009; Schutz, Bernard/B-1504-2010; Casey, Morag/C-9703-2010; Rowan, Sheila/E-3032-2010; Raab, Frederick/E-2222-2011 OI Freise, Andreas/0000-0001-6586-9901; Whiting, Bernard F/0000-0002-8501-8669; Papa, M.Alessandra/0000-0002-1007-5298; Taylor, Ian/0000-0001-5040-0772; Aulbert, Carsten/0000-0002-1481-8319; Tanner, David/0000-0003-1940-4710; Vecchio, Alberto/0000-0002-6254-1617; Finn, Lee Samuel/0000-0002-3937-0688; Ottewill, Adrian/0000-0003-3293-8450; Sigg, Daniel/0000-0003-4606-6526; Frey, Raymond/0000-0003-0341-2636; McClelland, David/0000-0001-6210-5842; Lueck, Harald/0000-0001-9350-4846; Strain, Kenneth/0000-0002-2066-5355; Pitkin, Matthew/0000-0003-4548-526X; Allen, Bruce/0000-0003-4285-6256; Sylvestre, Julien/0000-0001-8136-4348; NR 59 TC 159 Z9 159 U1 5 U2 25 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD JUN PY 2004 VL 69 IS 12 AR 122001 DI 10.1103/PhysRevD.69.122001 PG 16 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 838AA UT WOS:000222681600002 ER PT J AU Miller, M AF Miller, M TI Circular orbit approximation for binary compact objects in general relativity SO PHYSICAL REVIEW D LA English DT Article ID NEWTONIAN GRAVITATIONAL-RADIATION; QUASI-EQUILIBRIUM; NEUTRON-STARS; POINT MASSES; SYSTEMS AB One often-used approximation in the study of binary compact objects (i.e., black holes and neutron stars) in general relativity is the instantaneously circular orbit assumption. This approximation has been used extensively, from the calculation of innermost circular orbits to the construction of initial data for numerical relativity calculations. While this assumption is inconsistent with generic general relativistic astrophysical inspiral phenomena where the dissipative effects of gravitational radiation cause the separation of the compact objects to decrease in time, it is usually argued that the time scale of this dissipation is much longer than the orbital time scale so that the approximation of circular orbits is valid. Here, we quantitatively analyze this approximation using a post-Newtonian approach that includes terms up to order [Gm/(rc(2))](9/2) for nonspinning particles. By calculating the evolution of equal mass black-hole-black-hole binary systems starting with circular orbit configurations and comparing them to the more astrophysically relevant quasicircular solutions, we show that a minimum initial separation corresponding to at least 6 (3.5) orbits before merger is required in order to bound the detection event loss rate in gravitational wave detectors to below 5% (20%). In addition, we show that the detection event loss rate is greater than 95% for a range of initial separations that includes all modern calculations of the innermost stable circular orbit. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 37 TC 15 Z9 15 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD JUN PY 2004 VL 69 IS 12 AR 124013 DI 10.1103/PhysRevD.69.124013 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 838AA UT WOS:000222681600053 ER PT J AU Walther, JH Werder, T Jaffe, RL Koumoutsakos, P AF Walther, JH Werder, T Jaffe, RL Koumoutsakos, P TI Hydrodynamic properties of carbon nanotubes SO PHYSICAL REVIEW E LA English DT Article ID FLUID-SOLID INTERFACE; MOLECULAR-DYNAMICS SIMULATION; BOUNDARY-CONDITIONS; SHEAR-FLOW; WATER; SLIP; SURFACES; NANOPORES; GRAPHITE AB We study water flowing past an array of single walled carbon nanotubes using nonequilibrium molecular dynamics simulations. For carbon nanotubes mounted with a tube spacing of 16.4x16.4 nm and diameters of 1.25 and 2.50 nm, respectively, we find drag coefficients in reasonable agreement with the macroscopic, Stokes-Oseen solution. The slip length is -0.11 nm for the 1.25 nm carbon nanotube, and 0.49 for the 2.50 nm tube for a flow speed of 50 m/s, respectively, and 0.28 nm for the 2.50 nm tube at 200 m/s. A slanted flow configuration with a stream- and spanwise velocity component of 100 ms(-1) recovers the two-dimensional results, but exhibits a significant 88 nm slip along the axis of the tube. These results indicate that slip depends on the particular flow configuration. C1 Swiss Fed Inst Technol, Inst Computat Sci, Zurich, Switzerland. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Swiss Fed Inst Technol, Inst Computat Sci, Zurich, Switzerland. EM petros@inf.ethz.ch RI Koumoutsakos, Petros/A-2846-2008; Walther, Jens/D-9549-2015 OI Koumoutsakos, Petros/0000-0001-8337-2122; Walther, Jens/0000-0001-8100-9178 NR 34 TC 61 Z9 61 U1 0 U2 12 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0045 EI 2470-0053 J9 PHYS REV E JI Phys. Rev. E PD JUN PY 2004 VL 69 IS 6 AR 062201 DI 10.1103/PhysRevE.69.062201 PN 1 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 835RH UT WOS:000222502700111 PM 15244641 ER PT J AU Le Clercq, PC Bellan, J AF Le Clercq, PC Bellan, J TI Direct numerical simulation of a transitional temporal mixing layer laden with multicomponent-fuel evaporating drops using continuous thermodynamics SO PHYSICS OF FLUIDS LA English DT Article ID MACH-NUMBER TURBULENCE; VAPORIZATION; MIXTURES; MODEL; FLOWS; COMBUSTION; DROPLETS; DISTRIBUTIONS; DISPERSION; COMPONENTS AB A model of a temporal three-dimensional mixing layer laden with fuel drops of a liquid containing a large number of species is derived. The fuel model is based on continuous thermodynamics, whereby the composition is statistically described through a distribution function parametrized on the species molar weight. The drop temperature is initially lower than that of the carrier gas, leading to drop heat up and evaporation. The model describing the changes in the multicomponent (MC) fuel drop composition and in the gas phase composition due to evaporation encompasses only two more conservation equations when compared with the equivalent single-component (SC) fuel formulation. Single drop results of a MC fuel having a sharply peaked distribution are shown to compare favorably with a validated SC-fuel drop simulation. Then, single drop comparisons are performed between results from MC fuel and a representative SC fuel used as a surrogate of the MC fuel. Further, two mixing layer simulations are conducted with a MC fuel and they are compared to representative SC-fuel simulations conducted elsewhere. Examination of the results shows that although the global layer characteristics are generally similar in the SC and MC situations, the MC layers display a higher momentum-thickness-based Reynolds number at transition. Vorticity analysis shows that the SC layers exhibit larger vortical activity than their MC counterpart. An examination of the drop organization at transition shows more structure and an increased drop-number density for MC simulations in regions of moderate and high strain. These results are primarily attributed to the slower evaporation of MC-fuel drops than of their SC counterpart. This slower evaporation is due to the lower volatility of the higher molar weight species, and also to condensation of already-evaporated species on drops that are transported in regions of different gas composition. The more volatile species released in the gas phase earlier during the drop lifetime reside in the lower stream while intermediary molar weight species, which egress after the drops are entrained in the mixing layer, reside in the mixing layer and form there a very heterogeneous mixture; the heavier species that evaporate later during the drop lifetime tend to reside in regions of high drop number density. This leads to a segregation of species in the gas phase based on the relative evaporation time from the drops. The ensemble-average drop temperature becomes eventually larger/smaller than the initial drop temperature in MC/SC simulations. Neither this species segregation nor the drop temperature variation with respect to the initial temperature or as a function of the mass loading can be captured by the SC-fuel simulations. (C) 2004 American Institute of Physics. C1 CALTECH, Pasadena, CA 91125 USA. CALTECH, Pasadena, CA 91109 USA. Jet Prop Lab, Pasadena, CA 91109 USA. RP Le Clercq, PC (reprint author), CALTECH, Pasadena, CA 91125 USA. EM josette.bellan@jpl.nasa.gov NR 40 TC 12 Z9 12 U1 1 U2 4 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 2004 VL 16 IS 6 BP 1884 EP 1907 DI 10.1063/1.1688327 PG 24 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 819WB UT WOS:000221345600004 ER PT J AU Richards, JT Mulavara, AP Bloomberg, JJ AF Richards, JT Mulavara, AP Bloomberg, JJ TI Postural stability during treadmill locomotion as a function of the visual polarity and rotation of a three-dimensional virtual environment SO PRESENCE-TELEOPERATORS AND VIRTUAL ENVIRONMENTS LA English DT Article ID CANADIAN VESTIBULAR EXPERIMENTS; SPACE-FLIGHT; ROLL-VECTION; OPTIC FLOW; SPATIAL ORIENTATION; MENTAL-IMAGERY; LOWER-LIMB; WALKING; MOTION; REALITY AB Visual inputs provide us with important cues for orientation and self-movement perception during locomotion. The purpose of the present study was to better understand and quantify the effects of visual scene variables: visual polarity and visual scene rotation on postural stability during treadmill locomotion. During 60 s trials, subjects walked at 4.0 km/h while viewing a monoscopic, passive-immersive, 3D virtual room environment that contained either polarized or nonpolarized content and was back-projected onto a screen 1.5 m in front of them, one at a time. Scenes remained static for the first 30 s, then rotated about the roll, pitch, or yaw axis of the room at a constant rate of 30degrees/s for the remaining 30 s. Each subject saw each combination of visual polarity (polarized, nonpolarized) and scene rotation direction (roll, pitch, yaw) for three separate trials, There was a main effect of visual polarity on variability in torso linear X (fore-aft) position and torso roll and pitch angular orientations with polarized scenes causing more variability than nonpolarized scenes. For the polarized scenes only, variability in torso roll, pitch, and yaw angular orientations was increased for corresponding scene rotation directions, respectively. In general, rotating visual scenes caused increased variability in torso motion compared to static scenes. Visual polarity is an important consideration when designing virtual environment motion simulations. C1 Wyle Labs Inc, Neurosci Lab, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Neurosci Lab, Houston, TX 77058 USA. RP Richards, JT (reprint author), Wyle Labs Inc, Neurosci Lab, 1290 Hercules Dr,Suite 120,NL-272, Houston, TX 77058 USA. EM jason.richards1@jsc.nasa.gov NR 42 TC 15 Z9 15 U1 0 U2 4 PU M I T PRESS PI CAMBRIDGE PA FIVE CAMBRIDGE CENTER, CAMBRIDGE, MA 02142 USA SN 1054-7460 J9 PRESENCE-TELEOP VIRT JI Presence-Teleoper. Virtual Env. PD JUN PY 2004 VL 13 IS 3 BP 371 EP 384 DI 10.1162/1054746041422299 PG 14 WC Computer Science, Cybernetics; Computer Science, Software Engineering SC Computer Science GA 834XU UT WOS:000222445000010 ER PT J AU Weiss, BP Kim, SS Kirschvink, JL Kopp, RE Sankaran, M Kobayashi, A Komeili, A AF Weiss, BP Kim, SS Kirschvink, JL Kopp, RE Sankaran, M Kobayashi, A Komeili, A TI Magnetic tests for magnetosome chains in Martian meteorite ALH84001 SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID BIOGENIC MAGNETITE; VERWEY TRANSITION; CRYSTALS; MARS; MAGNETOFOSSILS; CARBONATES; ORIGIN; LIFE AB Transmission electron microscopy studies have been used to argue that magnetite crystals in carbonate from Martian meteorite ALH84001 have a composition and morphology indistinguishable from that of magnetotactic bacteria. It has even been claimed from scanning electron microscopy imaging that some ALH84001 magnetite crystals are aligned in chains. Alignment of magnetosomes in chains is perhaps the most distinctive of the six crystallographic properties thought to be collectively unique to magnetofossils. Here we use three rock magnetic techniques, low-temperature cycling, the Moskowitz test, and ferromagnetic resonance, to sense the bulk composition and crystallography of millions of ALH84001 magnetite crystals. The magnetic data demonstrate that although the magnetite is unusually pure and fine-grained in a manner similar to terrestrial magnetofossils, most or all of the crystals are not arranged in chains. C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Dept Chem & Chem Engn, Pasadena, CA 91125 USA. CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. Natl Inst Adv Ind Sci & Technol, Div Human Life Technol, Ikeda, Osaka 5638577, Japan. RP Weiss, BP (reprint author), CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. EM bweiss@gps.caltech.edu RI Kopp, Robert/B-8822-2008; Sankaran, R. Mohan/B-9668-2009 NR 28 TC 40 Z9 48 U1 4 U2 18 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD JUN 1 PY 2004 VL 101 IS 22 BP 8281 EP 8284 DI 10.1073/pnas.0402292101 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 826LY UT WOS:000221831800007 PM 15155900 ER PT J AU DellaCorte, C AF DellaCorte, C TI Reading TLT is just not good enough! SO TRIBOLOGY & LUBRICATION TECHNOLOGY LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP DellaCorte, C (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM cdellacorte@stle.org NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 0024-7154 J9 TRIBOL LUBR TECHNOL JI Tribol. Lubr. Technol. PD JUN PY 2004 VL 60 IS 6 BP 6 EP 6 PG 1 WC Engineering, Mechanical SC Engineering GA 825FW UT WOS:000221742400002 ER PT J AU Yang, HC Alouini, MS Simon, MK AF Yang, HC Alouini, MS Simon, MK TI Average error rate of NCFSK with multi-branch post-detection switched diversity SO WIRELESS COMMUNICATIONS & MOBILE COMPUTING LA English DT Article DE diversity techniques; post-detection combining; switched diversity; frequency shift keying; error rate analysis ID SELECTION DIVERSITY; FADING CHANNELS; SYSTEMS; PERFORMANCE AB We investigate the performance of non-coherent frequency shift keying (NCFSK) with multi-branch post-detection switched diversity systems. After an appropriate statistical description of the square-law detector output, we derive generic formulas for the symbol/bit error probability of NCFSK for both switch and stay combining (SSC) and switch and examine combining (SEC) schemes. We show that while the SSC scheme does not benefit from more than two diversity paths when the paths are identically distributed, the error performance of SEC improves as the number of antenna paths increases. We consider two detection schemes for NCFSK, one for M-ary FSK and another limited to only BFSK. We show that the second scheme leads to lower error probability performance when both are used to detect binary signals. The mathematical formalism is illustrated with a number of selected numerical examples. Copyright (C) 2004 John Wiley Sons, Ltd. C1 Univ Minnesota, Dept Elect & Comp Engn, Minneapolis, MN 55455 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yang, HC (reprint author), Univ Minnesota, Dept Elect & Comp Engn, Minneapolis, MN 55455 USA. EM hyang@ece.umn.edu NR 16 TC 1 Z9 1 U1 1 U2 1 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 1530-8669 J9 WIREL COMMUN MOB COM JI Wirel. Commun. Mob. Comput. PD JUN PY 2004 VL 4 IS 4 BP 351 EP 367 DI 10.1002/wcm.138 PG 17 WC Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 831TB UT WOS:000222217900002 ER PT J AU Lanari, R Berardino, P Borgstrom, S Del Gaudio, C De Martino, P Fornaro, G Guarino, S Ricciardi, GP Sansosti, E Lundgren, P AF Lanari, R Berardino, P Borgstrom, S Del Gaudio, C De Martino, P Fornaro, G Guarino, S Ricciardi, GP Sansosti, E Lundgren, P TI The use of IFSAR and classical geodetic techniques for caldera unrest episodes: application to the Campi Flegrei uplift event of 2000 SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article; Proceedings Paper CT EGS 26th General Meeting CY MAR, 2001 CL NICE, FRANCE SP EGS DE caldera unrest; global positioning system; SAR interferometry; volcano deformation ID RADAR INTERFEROMETRY; SURFACE DEFORMATION; GROUND DEFORMATIONS; SAR INTERFEROGRAMS; HALF-SPACE; TOPOGRAPHY; EVOLUTION; MOVEMENT AB Campi Flegrei caldera has a long history of large surface deformation, with displacements of several meters in the 1970s and early 1980s. Its location within a densely populated urban area underscores the importance of understanding the relationship between large and episodic deformation events and their source mechanisms. The primary observable of the caldera's activity is its surface deformation. Classical geodetic approaches such as leveling, have been complemented by the more advanced measurements of the Global Positioning System (GPS) and Synthetic Aperture Radar (SAR) interferometry. In this work we focus on the Campi Flegrei caldera uplift event that occurred from early spring to late summer 2000. Our goal is to highlight the potential to integrate interferometric SAR (IFSAR), GPS, and classical leveling data for ground deformation studies and source modeling. We compare models for the deformation source constrained by inversion of the differential IFSAR data (DIFSAR) with the model's prediction for the GPS and leveling data. Resolution of possible changes in the source mechanism for Campi Flegrei caldera are limited by differences in the temporal, spatial and deformation component strengths of each data set. In the future, overcoming these data deficiencies will be important for resolving the dynamics of volcano systems and for volcanic hazard mitigation. (C) 2003 Elsevier B.V. All rights reserved. C1 CNR, Ist Rilevamento Elettomagnet Ambiente, I-80124 Naples, Italy. Ist Nazl Geofis & Vulcanol, Osservatorio Vesuviano, I-80124 Naples, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lanari, R (reprint author), CNR, Ist Rilevamento Elettomagnet Ambiente, Via Diocleziano 328, I-80124 Naples, Italy. EM lanari.r@irea.cnr.it; berardino.p@irea.cnr.it; sven@ov.ingv.it; delgaudio@ov.ingv.it; demartino@ov.ingv.it; fornaro.g@irea.cnr.it; guarino.s@irea.cnr.it; ricciard@ov.ingv.it; sansosti.e@irea.cnr.it; paul@weed.jpl.nasa.gov RI Sansosti, Eugenio/F-7297-2011; De Martino, Prospero/E-4272-2014; OI Sansosti, Eugenio/0000-0002-5051-4056; De Martino, Prospero/0000-0002-9584-3347; Fornaro, Gianfranco/0000-0002-1679-607X NR 28 TC 43 Z9 43 U1 1 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 MAY 30 PY 2004 VL 133 IS 1-4 BP 247 EP 260 DI 10.1016/S0377-0273(03)00401-3 PG 14 WC Geosciences, Multidisciplinary SC Geology GA 818YL UT WOS:000221280300016 ER PT J AU Choi, H Bindschadler, R AF Choi, H Bindschadler, R TI Cloud detection in Landsat imagery of ice sheets using shadow matching technique and automatic normalized difference snow index threshold value decision SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE Landsat ETM; clouds; shadow; classification; ice sheet; NDSI; automatic cloud cover assessment (ACCA) AB This work presents a new algorithm designed to detect clouds in satellite visible and infrared (IR) imagery of ice sheets. The approach identifies possible cloud pixels through the use of the normalized difference snow index (NDSI). Possible cloud pixels are grown into regions and edges are determined. Possible cloud edges are then matched with possible cloud shadow regions using knowledge of the solar illumination azimuth. A scoring index quantifies the quality of each match resulting in a classified image. The best value of the NDSI threshold is shown to vary significantly, forcing the algorithm to be iterated through many threshold values. Computational efficiency is achieved by using sub-sampled images with only minor degradation in cloud-detection performance. The algorithm detects all clouds in each of eight test Landsat-7 images and makes no incorrect cloud classifications. (C) 2004 Elsevier B.V. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Sci Applicat Int Corp, Greenbelt, MD 20771 USA. Sci Applicat Int Corp, San Diego, CA 92121 USA. RP Choi, H (reprint author), NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Sci Applicat Int Corp, Code 971, Greenbelt, MD 20771 USA. EM choi@ice.gsfc.nasa.gov; bob@igloo.gsfc.nasa.gov NR 6 TC 34 Z9 42 U1 2 U2 18 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAY 30 PY 2004 VL 91 IS 2 BP 237 EP 242 DI 10.1016/j.rse.2004.03.007 PG 6 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 828XC UT WOS:000222006000010 ER PT J AU Huang, FT Reber, CA AF Huang, FT Reber, CA TI Nonmigrating semidiurnal and diurnal tides at 95 km based on wind measurements from the High Resolution Doppler Imager on UARS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE mesospheric tides ID ATMOSPHERE RESEARCH SATELLITE; LATENT-HEAT RELEASE; IMAGING INTERFEROMETER; LOWER THERMOSPHERE; MESOSPHERE; VARIABILITY; MIDDLE; HRDI; LATITUDE; MODEL AB For more than a decade, derived results from the High Resolution Doppler Imager (HRDI) on UARS have provided an enormous amount of new and invaluable information on the global variability of atmospheric winds. These and other results have given added impetus to theoretical modeling efforts. Until recent years, the large majority of investigations have focused on migrating tides, and now more results on nonmigrating tides have become available. We provide new results for semidiurnal and diurnal nonmigrating tides based on data from HRDI at 95 km. Much of these results have not been obtained before, and they are substantially different from those that have been previously reported. Our amplitudes are usually significantly larger, with more periodicities in both day of year and latitude than results that have previously appeared in the literature. We also find components (up to longitude wave number 3) that are significant and have not been presented before and that traveling components of larger-longitude wave numbers 4, 5, and 6 can reach several m/s in amplitude. We compare our results with earlier results based on HRDI measurements and from selected models. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Huang, FT (reprint author), 8359 Canning Terrace, Greenbelt, MD 20770 USA. EM fthuang@comcast.net; carl.a.reber@nasa.gov NR 30 TC 28 Z9 28 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 MAY 28 PY 2004 VL 109 IS D10 AR D10110 DI 10.1029/2003JD004442 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 827OS UT WOS:000221910800003 ER PT J AU Green, JL Boardsen, S Garcia, L Fung, SF Reinisch, BW AF Green, JL Boardsen, S Garcia, L Fung, SF Reinisch, BW TI Seasonal and solar cycle dynamics of the auroral kilometric radiation source region SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE auroral kilometric radiation; seasonal variation; solar cycle variation; auroral density cavity; auroral acceleration region ID PARTICLE-ACCELERATION; ANGULAR-DISTRIBUTION; PLASMA-DENSITY; SPACECRAFT; RADIO; AKR; DEPENDENCE; GENERATION; FREQUENCY; INTENSITY AB Several year's worth of observations from the plasma wave instruments on both Magnetopause-to-Aurora Global Exploration ( IMAGE) and Polar spacecraft are used to study the seasonal and solar cycle variations in the spectrum of auroral kilometric radiation (AKR). Only AKR observations when the spacecraft were in the Northern Hemisphere emission cones were used. The results from the seasonal analysis show significant changes in the AKR spectrum as a function of dipole tilt. The average AKR spectral peak for positive dipole tilt is similar to150 kHz but is similar to300 kHz during times of negative dipole tilt. In addition, the average emission spectrum for positive tilt is up to two orders of magnitude weaker over the 200-500 kHz frequency range when compared with the average emission spectrum for negative tilt. Assuming the cyclotron maser mechanism for AKR, these results imply that the AKR source region ( the auroral density cavity) moves to higher altitudes during the summer and to lower altitudes during the winter. Using data from the DE-1 plasma wave instrument, the magnetic local time of average AKR source region is also investigated with dipole tilt. From these observations it is found that for negative dipole tilt a broad AKR source region exists, ranging from similar to18 to similar to24 MLT, with peak emission coming from similar to20 MLT. In comparison, under positive dipole tilt the source region narrows (similar to20 to similar to24 MLT) with peak emission at similar to22 MLT. Taking into account the above seasonal effect, a comparison of the average spectra from IMAGE and Polar plasma wave data also demonstrates a solar cycle effect. The average AKR spectrum at solar maximum has the same structure with dipole tilt as at solar minimum but is typically lower ( by as much as 1-2 orders of magnitude). The observations presented support the concept that the expected increases in ionospheric densities (with positive dipole tilt for the Northern Hemisphere and solar EUV flux increases during solar maximum) play a significant role in magnetospheric-ionospheric coupling by: ( 1) shortening the altitude range of the auroral plasma cavity, (2) confining the cavity to a smaller range of MLT and closer to midnight, and ( 3) decreasing the overall intensity of AKR by lessening the density depth of the auroral density cavity. The results of this study should be taken into account in future studies of using AKR as a substorm index and other statistical emission cone studies at both low and high frequencies. C1 NASA, Goddard Space Flight Ctr, Govt Serv L3, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, QSS Grp Inc, Greenbelt, MD 20771 USA. Univ Massachusetts, Ctr Atmospher Res, Environm Earth & Atmospher Sci Dept, Lowell, MA 01854 USA. RP Green, JL (reprint author), NASA, Goddard Space Flight Ctr, Govt Serv L3, Greenbelt, MD 20771 USA. EM james.green@nasa.gov RI Fung, Shing/F-5647-2012 NR 36 TC 23 Z9 24 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 MAY 28 PY 2004 VL 109 IS A5 AR A05223 DI 10.1029/2003JA010311 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827PI UT WOS:000221912500002 ER PT J AU Leamon, RJ Canfield, RC Jones, SL Lambkin, K Lundberg, BJ Pevtsov, AA AF Leamon, RJ Canfield, RC Jones, SL Lambkin, K Lundberg, BJ Pevtsov, AA TI Helicity of magnetic clouds and their associated active regions SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE magnetic clouds; active regions; electric currents; solar eruptions; magnetic helicity ID CORONAL MASS EJECTIONS; SOLAR; FIELDS; FLUX; WIND; MORPHOLOGY; SPACECRAFT; TELESCOPE; EVOLUTION; TOPOLOGY AB In this work we relate the magnetic and topological parameters of twelve interplanetary magnetic clouds to associated solar active regions. We use a cylindrically symmetric constant-alpha force-free model to derive field line twist, total current, and total magnetic flux from in situ observations of magnetic clouds. We compare these properties with those of the associated solar active regions, which we infer from solar vector magnetograms. Our comparison of fluxes and currents reveals: (1) the total flux ratios Phi(MC)/Phi(AR) tend to be of order unity, (2) the total current ratios I-MC/I-AR are orders of magnitude smaller, and (3) there is a statistically significant proportionality between them. Our key findings in comparing total twists alphaL are that (1) the values of (alphaL)(MC) are typically an order of magnitude greater than those of (alphaL)(AR) and (2) there is no statistically significant sign or amplitude relationship between them. These findings compel us to believe that magnetic clouds associated with active region eruptions are formed by magnetic reconnection between these regions and their larger-scale surroundings, rather than simple eruption of preexisting structures in the corona or chromosphere. C1 Dartmouth Coll, Dept Phys & Astron, Hanover, NH 03755 USA. Natl Univ Ireland Univ Coll Dublin, Expt Phys Dept, Dublin 4, Ireland. Univ Arizona, Dept Phys, Tucson, AZ 85721 USA. Natl Solar Observ, Sunspot, NM 88349 USA. RP Leamon, RJ (reprint author), NASA, L3 Commun, Goddard Space Flight Ctr, Greenbelt, MD 20770 USA. EM leamon@grace.nascom.nasa.gov; canfield@physics.montana.edu; sarah.l.jones@dartmouth.edu; keithlambkin@hotmail.com; lundberg@email.arizona.edu; apevtsov@nso.edu RI Jones, Sarah/D-5293-2012 OI Jones, Sarah/0000-0002-3816-4954 NR 48 TC 52 Z9 52 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 MAY 27 PY 2004 VL 109 IS A5 AR A05106 DI 10.1029/2003JA010324 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827PH UT WOS:000221912300003 ER PT J AU Ohmoto, H Watanabe, Y Kumazawa, K AF Ohmoto, H Watanabe, Y Kumazawa, K TI Evidence from massive siderite beds for a CO2-rich atmosphere before, 1.8 billion years ago SO NATURE LA English DT Article ID CARBON-DIOXIDE CONCENTRATIONS; IRON-FORMATION; STABLE ISOTOPE; SOUTH-AFRICA; WESTERN-AUSTRALIA; OXYGEN; ORIGIN; RICH; GEOCHEMISTRY; SUPERGROUP AB It is generally thought that, in order to compensate for lower solar flux and maintain liquid oceans on the early Earth, methane must have been an important greenhouse gas before similar to2.2 billion years (Gyr) ago(1-5). This is based upon a simple thermodynamic calculation that relates the absence of siderite (FeCO3) in some pre-2.2-Gyr palaeosols to atmospheric CO2 concentrations that would have been too low to have provided the necessary greenhouse effect(1). Using multi-dimensional thermodynamic analyses and geological evidence, we show here that the absence of siderite in palaeosols does not constrain atmospheric CO2 concentrations. Siderite is absent in many palaeosols (both pre- and post-2.2-Gyr in age) because the O-2 concentrations and pH conditions in well-aerated soils have favoured the formation of ferric (Fe3+)-rich minerals, such as goethite, rather than siderite. Siderite, however, has formed throughout geological history in subsurface environments, such as euxinic seas, where anaerobic organisms created H-2-rich conditions. The abundance of large, massive siderite-rich beds in pre-1.8-Gyr sedimentary sequences and their carbon isotope ratios indicate that the atmospheric CO2 concentration was more than 100 times greater than today, causing the rain and ocean waters to be more acidic than today. We therefore conclude that CO2 alone ( without a significant contribution from methane) could have provided the necessary greenhouse effect to maintain liquid oceans on the early Earth. C1 Penn State Univ, Astrobiol Res Ctr, NASA, Astrobiol Inst, University Pk, PA 16802 USA. Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. Oyo Corp, Miyazaki Branch, Miyazaki 099561, Japan. RP Ohmoto, H (reprint author), Penn State Univ, Astrobiol Res Ctr, NASA, Astrobiol Inst, University Pk, PA 16802 USA. EM ohmoto@geosc.psu.edu NR 31 TC 125 Z9 131 U1 4 U2 33 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 27 PY 2004 VL 429 IS 6990 BP 395 EP 399 DI 10.1038/nature02573 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 823WN UT WOS:000221644600034 PM 15164058 ER PT J AU Cardellach, E Ao, CO Juarez, MD Hajj, GA AF Cardellach, E Ao, CO Juarez, MD Hajj, GA TI Carrier phase delay altimetry with GPS-reflection/occultation interferometry from low Earth orbiters SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID REFLECTED SIGNALS; OCEAN ALTIMETRY; SYSTEM; PARIS AB GPS signals reflected off the surface of the Earth can be detected by receivers aboard occulting Low Earth Orbiters (LEOs). In this work, carrier phase interferometry between the reflected and direct occultation signals is performed to infer its relative delay at centimetric error. Our analysis shows that submeter sensitivity on the surface heights can formally be reached with this technique. The potential applications to polar ice altimetry are discussed. C1 CALTECH, NASA Jet Prop Lab, Pasadena, CA 91109 USA. RP Cardellach, E (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS 42, Cambridge, MA 02138 USA. EM ecardellach@cfa.harvard.edu; chi.o.ao@jpl.nasa.gov; mtj@jpl.nasa.gov; george.a.hajj@jpl.nasa.gov RI Cardellach, Estel/C-9418-2012 OI Cardellach, Estel/0000-0001-8908-0972 NR 13 TC 30 Z9 31 U1 1 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 MAY 26 PY 2004 VL 31 IS 10 AR L10402 DI 10.1029/2004GL019775 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 827OK UT WOS:000221909900005 ER PT J AU Crawford, JH Heald, CL Fuelberg, HE Morse, DM Sachse, GW Emmons, LK Gille, JC Edward, DP Deeter, MN Chen, G Olson, JR Connors, VS Kittaka, C Hamlin, AJ AF Crawford, JH Heald, CL Fuelberg, HE Morse, DM Sachse, GW Emmons, LK Gille, JC Edward, DP Deeter, MN Chen, G Olson, JR Connors, VS Kittaka, C Hamlin, AJ TI Relationship between Measurements of Pollution in the Troposphere (MOPITT) and in situ observations of CO based on a large-scale feature sampled during TRACE-P SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE TRACE-P; MOPITT; carbon monoxide ID PACIFIC EXPLORATORY MISSION; CARBON-MONOXIDE; INSTRUMENT; SATELLITE; OZONE; AIRCRAFT; PERIOD AB During Transport and Chemical Evolution over the Pacific (TRACE-P), there were several opportunities to perform in situ sampling coincident with overpasses of the Measurements of Pollution in the Troposphere (MOPITT) instrument on board the EOS Terra satellite. This sampling consisted of in situ vertical profiles of CO by NASA's DC-8 aircraft intended to provide data useful for validating MOPITT observations of CO column. One particular profile conducted over the central North Pacific revealed a layer of pollution characterized by CO mixing ratios more than double background values. Sampling of the surrounding region by both the NASA DC-8 and P-3B aircraft showed this layer to have a considerable geographic extent, at least 25degrees longitude (similar to2500 km) and 4degrees latitude (similar to400 km). Using back trajectory analysis, this polluted layer is followed back in time and compared with four consecutive MOPITT overpasses. MOPITT observations during these four overpasses agree well with the location of the layer as inferred by the trajectories; however, the detected CO column amount increases backward in time by just over 20%. Further analysis shows that the majority of this change in detected column abundance is consistent with two factors: ( 1) changes in the thickness of the polluted layer over time (9 +/- 3%) and (2) changes in retrieved column abundance due to the altitude of the layer (7 +/- 3%). This demonstrates that there are both real and artificial sources of variability that must be understood before MOPITT observations can be quantitatively useful. An unexpected finding was the difference in the variance of MOPITT observations depending on whether observations were taken under daylight or nighttime conditions. The variance in daytime observations of the polluted layer was approximately double that for nighttime data. The results of this analysis indicate that targeted in situ sampling of large-scale pollution events can provide insight leading to more realistic interpretation of MOPITT observations. Strategies for sampling such events repeatedly during their evolution could also provide more interesting opportunities for validation. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP NASA, Langley Res Ctr, Mail Stop 483, Hampton, VA 23681 USA. EM james.h.crawford@nasa.gov; heald@fas.harvard.edu; fuelberg@met.fsu.edu; g.w.sachse@larc.nasa.gov; emmons@ucar.edu; gille@ncar.ucar.edu; edward@uars1.acd.ucar.edu; mnd@ucar.edu; g.chen@larc.nasa.gov; j.r.olson@larc.nasa.gov; vickie@stormy.larc.nasa.gov; c.kittaka@larc.nasa.gov; reh@mtu.edu RI Heald, Colette/A-6813-2011; Crawford, James/L-6632-2013; Deeter, Merritt/O-6078-2016; Emmons, Louisa/R-8922-2016 OI Crawford, James/0000-0002-6982-0934; Deeter, Merritt/0000-0002-3555-0518; Emmons, Louisa/0000-0003-2325-6212 NR 21 TC 14 Z9 14 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 26 PY 2004 VL 109 IS D15 AR D15S04 DI 10.1029/2003JD004308 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 827OV UT WOS:000221911100002 ER PT J AU Rignot, E Braaten, D Gogineni, SP Krabill, WB McConnell, JR AF Rignot, E Braaten, D Gogineni, SP Krabill, WB McConnell, JR TI Rapid ice discharge from southeast Greenland glaciers SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID RADAR INTERFEROMETRY; SHEET; PARTS; FLOW AB Interferometric synthetic-aperture radar (InSAR) observations of southeast Greenland glaciers acquired by the Earth Remote Sensing Satellites (ERS-1/2) in 1996 were combined with ice sounding radar data collected in the late 1990s to estimate a total discharge of 46 +/- 3 km 3 ice per year between 62degreesN and 66degreesN, which is significantly lower than a mass input of 29 +/- 3 km 3 ice per year calculated from a recent compilation of snow accumulation data. Further north, Helheim Glacier discharges 23 +/- 1 km(3)/yr vs 30 +/- 3 km(3)/yr accumulation; Kangerdlugssuaq Glacier discharges 29 +/- 2 km(3)/yr vs 23 +/- 2 km(3)/yr; and Daugaard-Jensen Glacier discharges 10.5 +/- 0.6 km(3)/yr vs 10.5 +/- 1 km(3)/yr. The mass balance of east Greenland glaciers is therefore dominated by the negative mass balance of southeast Greenland glaciers (-17 +/- 4 km(3)/yr), equivalent to a sea level rise of 0.04 +/- 0.01 mm/yr. Warmer and drier conditions cannot explain the imbalance which we attribute to long-term changes in ice dynamics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Kansas, Radar Syst & Remote Sensing Lab, Lawrence, KS 66045 USA. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Lab Hydrospher Proc, Wallops Isl, VA 23337 USA. Univ Nevada, Desert Res Inst, Div Hydrol Sci, Reno, NV 89506 USA. RP Rignot, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 200-227, Pasadena, CA 91109 USA. EM eric.rignot@jpl.nasa.gov; pkanagar@ittc.ku.edu; gogineni@ittc.ku.edu; krabill@osb1.wff.nasa.gov; jmcconn@dri.edu RI Rignot, Eric/A-4560-2014 OI Rignot, Eric/0000-0002-3366-0481 NR 19 TC 49 Z9 49 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 25 PY 2004 VL 31 IS 10 AR L10401 DI 10.1029/2004GL019474 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 827OJ UT WOS:000221909800002 ER PT J AU Djikaev, YS Napari, I Laaksonen, A AF Djikaev, YS Napari, I Laaksonen, A TI On the closure conjectures for the Gibbsian approximation model of a binary droplet SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MULTIDIMENSIONAL KINETIC-THEORY; NUCLEATION THEORY; SURFACTANT SOLUTIONS; PHASE-TRANSITIONS; WATER-SYSTEMS; 1ST KIND; THERMODYNAMICS; SIZE; ADSORPTION; NUCLEUS AB Within the framework of Gibbsian thermodynamics, a binary droplet is regarded to consist of a uniform interior and dividing surface. The properties of the droplet interior are those of the bulk liquid solution, but the dividing surface is a fictitious phase whose chemical potentials cannot be rigorously determined. The state of the nucleus interior and free energy of nucleus formation can be found without knowing the surface chemical potentials, but the latter are still needed to determine the state of the whole nucleus (including the dividing surface) and develop the kinetics of nucleation. Thus it is necessary to recur to additional conjectures in order to build a complete, thermodynamic, and kinetic theory of nucleation within the framework of the Gibbsian approximation. Here we consider and analyze the problem of closing the Gibbsian approximation droplet model. We identify mu- and Gamma-closure conjectures concerning the surface chemical potentials and excess surface coverages, respectively, for the droplet surface of tension. With these two closure conjectures, the Gibbsian approximation model of a binary droplet becomes complete so that one can determine both the surface and internal characteristics of the whole nucleus and develop the kinetic theory, based on this model. Theoretical results are illustrated by numerical evaluations for binary nucleation in a water-methanol vapor mixture at T=298.15 K. Numerical results show a striking increase in the droplet surface tension with decreasing droplet size at constant overall droplet composition. A comparison of the Gibbsian approximation with density functional calculations for a model surfactant system indicate that the excess surface coverages from the Gibbsian approximation are accurate enough for large droplets and droplets that are not too concentrated with respect to the solute. (C) 2004 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Helsinki, Dept Phys Sci, FIN-00014 Helsinki, Finland. Univ Kuopio, Dept Appl Phys, FIN-70211 Kuopio, Finland. RP Djikaev, YS (reprint author), NASA, Ames Res Ctr, MS 245-4, Moffett Field, CA 94035 USA. EM djikaev@chem.ucla.edu RI Laaksonen, Ari/B-5094-2011 OI Laaksonen, Ari/0000-0002-1657-2383 NR 41 TC 8 Z9 8 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 22 PY 2004 VL 120 IS 20 BP 9752 EP 9762 DI 10.1063/1.1698575 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 818TV UT WOS:000221268300039 PM 15267991 ER PT J AU Feng, K De Boni, L Misoguti, L Mendonca, CR Meador, M Hsu, FL Bu, XR AF Feng, K De Boni, L Misoguti, L Mendonca, CR Meador, M Hsu, FL Bu, XR TI Y-shaped two-photon absorbing molecules with an imidazole-thiazole core SO CHEMICAL COMMUNICATIONS LA English DT Article ID NONLINEAR-OPTICAL CHROMOPHORES; ABSORPTION; DERIVATIVES; FLUORESCENCE; DESIGN AB Two new classes of two-photon absorbing Y-shaped molecules have been developed to possess an imidazole-thiazole core and a stilbene-type conjugation pathway with either nitro or sulfonyl as terminal electron-accepting group. C1 Dept Chem, Atlanta, GA 30314 USA. NASA, Ctr High Performance Polymers & Composites, Atlanta, GA 30314 USA. Inst Fis Sao Carlos, Dept Fis & Ciencia Mat, BR-13560970 Sao Carlos, SP, Brazil. NASA, Polymer Branch, Glenn Res Ctr, Cleveland, OH 44135 USA. USA, Edgewood Chem & Biol Ctr, Aberdeen Proving Ground, MD 21010 USA. RP Bu, XR (reprint author), Dept Chem, Atlanta, GA 30314 USA. EM crmendon@if.sc.usp.br; xbu@cau.edu RI De Boni, Leonardo/B-9066-2012; Misoguti, Lino/C-2462-2012; Group, Photonics/D-3910-2012; Mendonca, Cleber/B-9050-2012; Sao Carlos Institute of Physics, IFSC/USP/M-2664-2016 OI De Boni, Leonardo/0000-0002-1875-1852; Misoguti, Lino/0000-0001-6624-8453; FU NCRR NIH HHS [G12-RR03062] NR 27 TC 32 Z9 32 U1 2 U2 5 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 1359-7345 J9 CHEM COMMUN JI Chem. Commun. PD MAY 21 PY 2004 IS 10 BP 1178 EP 1180 DI 10.1039/b402019g PG 3 WC Chemistry, Multidisciplinary SC Chemistry GA 828XZ UT WOS:000222008300013 PM 15136827 ER PT J AU Bauschlicher, CW Ricca, A Xue, YQ Ratner, MA AF Bauschlicher, CW Ricca, A Xue, YQ Ratner, MA TI Current-voltage curves for molecular junctions: pyrene vs diphenylacetylene SO CHEMICAL PHYSICS LETTERS LA English DT Article ID BASIS-SETS; ELECTRONIC DEVICES; ATOMS; POTENTIALS; FORMALISM; TRANSPORT; EXCHANGE; ENERGY; WIRES AB The I-V curves are computed for 2,7-dithiolpyrene and 4,4'-dithiol-diphenylacetylene between two Au(1 1 1) surfaces. For a given bias, up to about 2.5 eV. the current for 2,7-dithiolpyrene is about half that for 4,4'-dithiol-diphenylacetylene. However, the fused benzene rings in 2,7-dithiolpyrene eliminate the loss of current associated with rotation about the central C-2 that can occur for 4,4'-dithiol-diphenylacetylene. (C) 2004 Elsevier B.V. All rights reserved. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. Northwestern Univ, Mat Res Ctr, Evanston, IL 60208 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 NR 28 TC 15 Z9 15 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 21 PY 2004 VL 390 IS 1-3 BP 246 EP 249 DI 10.1016/j.cplett.2004.04.035 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 823QP UT WOS:000221628400045 ER PT J AU Aires, F Prigent, C Rossow, WB AF Aires, F Prigent, C Rossow, WB TI Neural network uncertainty assessment using Bayesian statistics with application to remote sensing: 3. Network Jacobians SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE remote sensing; uncertainty; neural networks ID INDEPENDENT COMPONENT ANALYSIS; TIME-SERIES; RETRIEVAL; MULTIVARIATE; INSTRUMENT AB Used for regression fitting, neural network (NN) models can be used effectively to represent highly nonlinear, multivariate functions. In this situation, most emphasis has been on estimating the output errors, but almost no attention has been given to errors associated with the internal structure of the NN model. The complex relationships linking the inputs to the outputs inside the network are the essence of the model and assessing their physical meaning makes all the difference between a "black box'' model with small output errors and a physically meaningful model that will provide insight on the problem and will have better generalization properties. Such dependency structures can, for example, be described by the NN Jacobians: they indicate the sensitivity of one output with respect to the inputs of the model. Estimating these Jacobians is essential for many other applications as well. We use a new method of uncertainty estimate developed in the work of Aires [ 2004] to investigate the robustness of the quantities that characterize the NN structure. A regularization strategy based on principal component analysis is proposed to suppress the multicolinearities that are a major concern when analyzing the internal structure of such a model. The theory is applied to the remote sensing application already presented in the work of Aires [ 2004] and Aires et al. [ 2004]. C1 Columbia Univ, NASA, Goddard Inst Space Studies, Dept Appl Phys & Appl Math, New York, NY 10025 USA. Ecole Polytech, CNRS, Meteorol Dynam Lab, IPSL, F-91128 Palaiseau, France. Observ Paris, CNRS, LERMA, F-75014 Paris, France. RP Columbia Univ, NASA, Goddard Inst Space Studies, Dept Appl Phys & Appl Math, 2880 Broadway, New York, NY 10025 USA. EM faires@giss.nasa.gov; catherine.prigent@obspm.fr; wrossow@giss.nasa.gov RI Rossow, William/F-3138-2015 NR 25 TC 17 Z9 17 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 21 PY 2004 VL 109 IS D10 AR D10305 DI 10.1029/2003JD004175 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 823KS UT WOS:000221611400003 ER PT J AU Aires, F Prigent, C Rossow, WB AF Aires, F Prigent, C Rossow, WB TI Neural network uncertainty assessment using Bayesian statistics with application to remote sensing: 2. Output errors SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE remote sensing; uncertainty; neural networks ID INFRARED SATELLITE-OBSERVATIONS; WATER-VAPOR; RETRIEVAL; SURFACE; LAND; MICROWAVE; TEMPERATURES; INSTRUMENT; PROFILES AB A technique to estimate the uncertainties of the parameters of a neural network model, i.e., the synaptic weights, was described in the work of Aires [2004]. Using these weight uncertainty estimates, we compute the uncertainties in the network outputs (i.e., error bars and correlation structure of these errors). Such quantities are very important for evaluating any application of the neural network technique. The theory is applied to the same remote sensing problem as in the work of Aires [ 2004] concerning the retrieval of surface skin temperature, microwave surface emissivities and integrated water vapor content from a combined analysis of microwave and infrared observations over land. C1 Columbia Univ, NASA, Goddard Inst Space Studies, Dept Appl Phys & Appl Math, New York, NY 10025 USA. Ecole Polytech, CNRS, Meteorol Dynam Lab, IPSL, F-91128 Palaiseau, France. Observ Paris, CNRS, LERMA, F-75014 Paris, France. RP Columbia Univ, NASA, Goddard Inst Space Studies, Dept Appl Phys & Appl Math, 2880 Broadway, New York, NY 10025 USA. EM faires@giss.nasa.gov; catherine.prigent@obspm.fr; wrossow@giss.nasa.gov RI Rossow, William/F-3138-2015 NR 27 TC 12 Z9 12 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 21 PY 2004 VL 109 IS D10 AR D10304 DI 10.1029/2003JD004174 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 823KS UT WOS:000221611400002 ER PT J AU Aires, F AF Aires, F TI Neural network uncertainty assessment using Bayesian statistics with application to remote sensing: 1. Network weights SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE remote sensing; uncertainty; neural networks ID INFRARED SATELLITE-OBSERVATIONS; SENSOR MICROWAVE IMAGER; SURFACE; RETRIEVAL; LAND; CLASSIFICATION; TEMPERATURES; VARIABLES AB [1] Neural network techniques have proved successful for many inversion problems in remote sensing; however, uncertainty estimates are rarely provided. This study has three parts. In this article, we present an approach to evaluate uncertainties (i.e., error bars and the correlation structure of these errors) of the neural network parameters, the so-called "synaptic weights'' on the basis of a Bayesian technique. In contrast to more traditional approaches based on "point estimation'' of the neural network weights (i.e., only one set of weights is determined by the learning process), we assess uncertainties on such estimates to monitor the quality of the neural network model. Uncertainties of the network parameters are used in the following two papers to estimate uncertainties of the network output [Aires et al., 2004a] and of the network Jacobians [ Aires et al., 2004b]. These new theoretical developments are illustrated by applying them to the problem of retrieving surface skin temperature, microwave surface emissivities, and integrated water vapor content from a combined analysis of microwave and infrared observations over land. C1 Columbia Univ, NASA, Goddard Inst Space Studies, Dept Appl Phys & Appl Math, New York, NY 10025 USA. Ecole Polytech, CNRS, Meteorol Dynam Lab, IPSL, F-91128 Palaiseau, France. RP Aires, F (reprint author), Columbia Univ, NASA, Goddard Inst Space Studies, Dept Appl Phys & Appl Math, 2880 Broadway, New York, NY 10025 USA. EM faires@giss.nasa.gov NR 36 TC 14 Z9 14 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 MAY 21 PY 2004 VL 109 IS D10 AR D10303 DI 10.1029/2003JD004173 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 823KS UT WOS:000221611400001 ER PT J AU Drdla, K Browell, EV AF Drdla, K Browell, EV TI Microphysical modeling of the 1999-2000 Arctic winter: 3. Impact of homogeneous freezing on polar stratospheric clouds SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE polar stratospheric clouds; freezing; denitrification ID LARGE HNO3-CONTAINING PARTICLES; NUCLEATION RATE CONSTANTS; DENITRIFICATION; AEROSOLS; TEMPERATURES; VORTEX AB Simulations of the 1999-2000 winter have tested the effect on polar stratospheric clouds (PSCs) of the homogeneous freezing of liquid ternary solutions into nitric acid trihydrate (NAT) and nitric acid dihydrate (NAD). Proposed laboratory-derived volume-based and surface-based homogeneous freezing rates have both been examined, including different assumptions about the extrapolation of laboratory measurements to atmospheric conditions. Widespread PSC formation and denitrification are possible in several of the scenarios examined. However, the simulations are all unable to explain the solid-phase PSCs observed early in the 1999-2000 winter and are unable to reproduce the measured extent of vortex denitrification. These problems can both be attributed to the relatively cold temperatures, more than 5 K below the NAT condensation point, necessary for homogeneous freezing to be effective at producing solid-phase PSCs. Therefore synoptic-scale homogeneous freezing appears unlikely to be the primary mechanism responsible for solid-phase PSC formation. C1 NASA, Ames Res Ctr, Atmospher Phys Branch, Moffett Field, CA 94035 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP NASA, Ames Res Ctr, Atmospher Phys Branch, Mail Stop 245-4, Moffett Field, CA 94035 USA. EM Katja.Drdla@nasa.gov; edward.v.browell@nasa.gov NR 36 TC 10 Z9 10 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 21 PY 2004 VL 109 IS D10 AR D10201 DI 10.1029/2003JD004352 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 823KS UT WOS:000221611400004 ER PT J AU Wild, O Prather, MJ Akimoto, H Sundet, JK Isaksen, ISA Crawford, JH Davis, DD Avery, MA Kondo, Y Sachse, GW Sandholm, ST AF Wild, O Prather, MJ Akimoto, H Sundet, JK Isaksen, ISA Crawford, JH Davis, DD Avery, MA Kondo, Y Sachse, GW Sandholm, ST TI Chemical transport model ozone simulations for spring 2001 over the western Pacific: Regional ozone production and its global impacts SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE tropospheric ozone; western Pacific; meteorological variability ID TROPOSPHERIC OZONE; TRACE-P; NORTH PACIFIC; UNITED-STATES; EAST-ASIA; PHOTOCHEMISTRY; CHEMISTRY; CLIMATE; AIR; PHOTOLYSIS AB The spatial and temporal variation in ozone production over major source regions in East Asia during the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) measurement campaign in spring 2001 is assessed using a global chemical transport model. There is a strong latitudinal gradient in ozone production in springtime, driven by regional photochemistry, which rapidly diminishes as the season progresses. The great variability in meteorological conditions characteristic of East Asia in springtime leads to large daily variability in regional ozone formation, but we find that it has relatively little impact on the total global production. We note that transport processes effectively modulate and thus stabilize total ozone production through their influence over its location. However, the impact on the global ozone burden, important for assessing the effects of precursor emissions on tropospheric oxidizing capacity and climate, is sensitive to local meteorology through the effects of location on chemical lifetime. Stagnant, anticyclonic conditions conducive to substantial boundary layer ozone production typically allow little lifting of precursors into the free troposphere where greater ozone production could occur, and the consequent shorter chemical lifetime for ozone leads to relatively small impacts on global ozone. Conversely, cyclonic conditions with heavy cloud cover suppressing regional ozone production are often associated with substantial cloud convection, enhancing subsequent production in the free troposphere where chemical lifetimes are longer, and the impacts on global ozone are correspondingly greater. We find that ozone formation in the boundary layer and free troposphere outside the region of precursor emissions dominates total gross production from these sources in springtime, and that it makes a big contribution to the long range transport of ozone, which is greatest in this season. C1 Frontier Res Syst Global Change, Kanazawa Ku, Yokohama, Kanagawa 2360001, Japan. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Univ Oslo, Dept Geophys, Oslo, Norway. Univ Tokyo, Res Ctr Adv Sci & Technol, Meguro Ku, Tokyo 1538904, Japan. Univ Calif Irvine, Irvine, CA 92697 USA. RP Frontier Res Syst Global Change, Kanazawa Ku, 3172-25 Showa Machi, Yokohama, Kanagawa 2360001, Japan. EM oliver@jamstec.go.jp; mprather@uci.edu; akimoto@jamstec.go.jp; j.k.sundet@geofysikk.uio.no; i.s.a.isaksen@geofysikk.uio.no; j.h.crawford@larc.nasa.gov; douglas.davis@eas.gatech.edu; m.a.avery@larc.nasa.gov; kondo@atmos.rcast.u-tokyo.ac.jp; g.w.sachse@larc.nasa.gov; scott.sandholm@eas.gatech.edu RI Wild, Oliver/A-4909-2009; Kondo, Yutaka/D-1459-2012; Crawford, James/L-6632-2013 OI Wild, Oliver/0000-0002-6227-7035; Crawford, James/0000-0002-6982-0934 NR 48 TC 19 Z9 19 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 21 PY 2004 VL 109 IS D15 AR D15S02 DI 10.1029/2003JD004041 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 823KV UT WOS:000221611800001 ER PT J AU Watts, AL Andersson, N Williams, RL AF Watts, AL Andersson, N Williams, RL TI The oscillation and stability of differentially rotating spherical shells: the initial-value problem SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE gravitational waves; hydrodynamics; instabilities; stars : neutron; stars : rotation ID NEUTRON-STARS; DYNAMICAL STABILITY; CORE-COLLAPSE; PERFECT FLUIDS; R-MODES; INSTABILITY; EVOLUTION; PRINCIPLE; DISKS AB An understanding of the oscillations of differentially rotating systems is key to many areas of astrophysics. It is of particular relevance to the emission of gravitational waves from oscillating neutron stars, which are expected to possess significant differential rotation immediately after birth or binary merger. In a previous paper we analysed the normal modes of a simple system exhibiting differential rotation. In this complementary paper we address the initial-value problem for the same simple model using both analytical methods and numerical time-evolutions. We derive a necessary and sufficient condition for dynamical shear instability. We discuss the dynamical behaviour of the continuous spectrum in response to an initial perturbation, and show that certain singular solutions within the continuous spectrum appear physically indistinguishable from the discrete modes outside the continuous spectrum. C1 Univ Southampton, Sch Math, Southampton SO17 1BJ, Hants, England. RP Watts, AL (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 662, Greenbelt, MD 20771 USA. EM anna@milkyway.gsfc.nasa.gov NR 22 TC 12 Z9 12 U1 0 U2 0 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 21 PY 2004 VL 350 IS 3 BP 927 EP 938 DI 10.1111/j.1365-2966.2004.07695.x PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 827PP UT WOS:000221913200016 ER PT J AU Case, GL Altice, PP Cherry, ML Isbert, J Patterson, D Mitchell, JW AF Case, GL Altice, PP Cherry, ML Isbert, J Patterson, D Mitchell, JW TI Measurements of Compton scattered transition radiation at high Lorentz factors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE transition radiation; scintillator detectors; Compton scattering; cosmic rays ID ENERGY PARTICLES; IDENTIFICATION; DETECTOR; NUCLEI AB X-ray transition radiation can be used to measure the Lorentz factor of relativistic particles. Standard transition radiation detectors (TRDs) typically incorporate thin plastic foil, foam, or fiber radiators and gas-filled X-ray detectors, and are sensitive up to gamma similar to 10(4). To reach Lorentz factors up to gamma similar to 10(5), thicker, denser radiators can be used, which consequently produce X-rays of harder energies (greater than or equal to 100 keV). At these energies, scintillator detectors are more efficient in detecting the hard X-rays, and Compton scattering of the X-rays out of the path of the particle becomes important. The Compton scattering can be utilized to separate the transition radiation from the ionization background spatially. The use of conducting metal foils is predicted to yield enhanced signals compared to standard nonconducting plastic foils of the same dimensions. We have designed and built an inorganic scintillator-based Compton Scatter TRD optimized for high Lorentz factors and exposed it to high-energy electrons at the CERN SPS. We present the results of the accelerator tests and comparisons to simulations, demonstrating (1) the effectiveness of the Compton Scatter TRD approach; (2) the performance of conducting aluminum foils; and (3) the ability of a TRD to measure energies approximately an order of magnitude higher than previously used in very high-energy cosmic ray studies. (C) 2004 Elsevier B.V. All rights reserved. C1 Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Case, GL (reprint author), Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. EM case@phunds.phys.lsu.edu NR 19 TC 2 Z9 2 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 MAY 21 PY 2004 VL 524 IS 1-3 BP 257 EP 263 DI 10.1016/j.nima.2004.01.066 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 824IG UT WOS:000221679400025 ER PT J AU Brauer, B Chaban, GM Gerber, RB AF Brauer, B Chaban, GM Gerber, RB TI Spectroscopically-tested, improved, semi-empirical potentials for biological molecules: Calculations for glycine, alanine and proline SO PHYSICAL CHEMISTRY CHEMICAL PHYSICS LA English DT Article ID ANHARMONIC VIBRATIONAL SPECTROSCOPY; SELF-CONSISTENT-FIELD; DUAL-FREQUENCY 2D-IR; AB-INITIO; FORCE-FIELDS; EMPIRICAL POTENTIALS; N-METHYLACETAMIDE; HYDROGEN-BONDS; ALPHA-ALANINE; MATRICES KR AB A modification of the semi-empirical PM3 electronic structure method is proposed. It employs a coordinate scaling procedure, such that the harmonic frequencies from the modified PM3 potentials for lower-energy conformers of glycine (conformer 1), alanine (conformers I and 11) and proline (conformer 11), fit more closely with ab initio (MP2/DZP) harmonic frequencies. The anharmonic frequencies are then calculated using the modified PM3 surfaces with the Vibrational Self-Consistent Field (VSCF) and Correlation-Corrected VSCF (CC-VSCF) methods. The computed anharmonic frequencies are in very good accord with spectroscopic experiments for the three amino acids. The results are much superior to those obtained from standard (unscaled) PM3 potentials, indicating that the modified PM3 potentials may be used as high quality potentials for biological molecules, at least in the configuration ranges pertinent to vibrational spectroscopy. The scaling parameters computed for the lowest energy conformers listed above were tested for transferability: they were used in computing the anharmonic spectra of two other conformers (glycine 11 and proline 1). The good agreement of the resulting frequencies with observed frequencies, indicates the transferability of the scaling parameters. It is concluded from this study that the improved PM3 potentials offer accurate and computationally efficient force fields for vibrational spectroscopy calculations of biological molecules. Possible additional applications of the new potentials are discussed. C1 Hebrew Univ Jerusalem, Dept Chem Phys, IL-91904 Jerusalem, Israel. Hebrew Univ Jerusalem, Fritz Haber Res Ctr, IL-91904 Jerusalem, Israel. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92797 USA. RP Gerber, RB (reprint author), Hebrew Univ Jerusalem, Dept Chem Phys, IL-91904 Jerusalem, Israel. NR 61 TC 70 Z9 70 U1 0 U2 7 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 1463-9076 J9 PHYS CHEM CHEM PHYS JI Phys. Chem. Chem. Phys. PD MAY 21 PY 2004 VL 6 IS 10 BP 2543 EP 2556 DI 10.1039/b315326f PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 831GE UT WOS:000222182100002 ER PT J AU Baldocchi, DD Xu, LK Kiang, N AF Baldocchi, DD Xu, LK Kiang, N TI How plant functional-type, weather, seasonal drought, and soil physical properties alter water and energy fluxes of an oak-grass savanna and an annual grassland SO AGRICULTURAL AND FOREST METEOROLOGY LA English DT Article DE ecohydrology; evaporation; biosphere atmosphere interactions ID CARBON-DIOXIDE EXCHANGE; EDDY-COVARIANCE; DECIDUOUS FOREST; INTERANNUAL VARIABILITY; CONTROLLED ECOSYSTEMS; STOMATAL CONDUCTANCE; HYDROLOGIC PROCESSES; TEMPERATE GRASSLAND; PRAIRIE ECOSYSTEM; SUMMER DROUGHT AB Savannas and open grasslands often co-exist in semi-arid regions. Questions that remain unanswered and are of interest to biometeorologists include: how do these contrasting landscapes affect the exchanges of energy on seasonal and annual time scales; and, do biophysical constraints imposed by water supply and water demand affect whether the land is occupied by open grasslands or savanna? To address these questions, and others, we examine how a number of abiotic, biotic and edaphic factors modulate water and energy flux densities over an oak-grass savanna and an annual grassland that coexist in the same climate but on soils with different hydraulic properties. The net radiation balance was greater over the oak woodland than the grassland, despite the fact that both canopies received similar sums of incoming short and long wave radiation. The lower albedo and lower radiative surface temperature of the transpiring woodland caused it to intercept and retain more long and shortwave energy over the course of the year, and particularly during the summer dry period. The partitioning of available energy into sensible and latent heat exchanged over the two canopies differed markedly. The annual sum of sensible heat exchange over the woodland was 40% greater than that over the grassland (2.05 GJ m(-2) per year versus 1.46 GJ m(-2) per year). With regards to evaporation, the oak woodland evaporated about 380 mm of water per year and the grassland evaporated about 300 mm per year. Differences in available energy, canopy roughness, the timing of physiological functioning, water holding capacity of the soil and rooting depth of the vegetation explained the observed differences in sensible and latent heat exchange of the contrasting vegetation surfaces. The response of canopy evaporation to diminishing soil moisture was quantified by comparing normalized evaporation rates (in terms of equilibrium evaporation) with soil water potential and volumetric water content measurements. When soil moisture was ample normalized values of latent heat flux density were greater for the grassland (1.1-1.2) than for the oak savanna (0.7-0.8) and independent of moisture content. Normalized rates of evaporation over the grassland declined as volumetric water content dropped below 0.15 m(3) m(-3), which corresponded with a soil water potential of -1.5 MPa. The grassland senesced and quit transpiring when the volumetric water content of the soil dropped below -2.0 MPa. The oak trees, on the other hand, were able to transpire, albeit at low rates, under very dry soil conditions (soil water potentials below -4.0 MPa). The trees were able to endure such low water potentials and maintain basal levels of metabolism because ecological forcings kept the tree density and leaf area index of the woodland low, physiological factors forced the stomata to close progressively and the trees were able to tap deeper water sources (below 0.6 in) than the grasses. (C) 2003 Elsevier B.V. All rights reserved. C1 Univ Calif Berkeley, Ecosyst Sci Div, Dept Environm Sci Policy & Management, Berkeley, CA 94720 USA. Columbia Univ, NASA, Goddard Inst Space Studies, Ctr Climate Syst Res, New York, NY 10025 USA. RP Baldocchi, DD (reprint author), Univ Calif Berkeley, Ecosyst Sci Div, Dept Environm Sci Policy & Management, 151 Hilgard Hall, Berkeley, CA 94720 USA. EM baldocchi@nature.berkeley.edu RI Baldocchi, Dennis/A-1625-2009 OI Baldocchi, Dennis/0000-0003-3496-4919 NR 91 TC 258 Z9 273 U1 13 U2 156 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1923 J9 AGR FOREST METEOROL JI Agric. For. Meteorol. PD MAY 20 PY 2004 VL 123 IS 1-2 BP 13 EP 39 DI 10.1016/j.agrformet.2003.11.006 PG 27 WC Agronomy; Forestry; Meteorology & Atmospheric Sciences SC Agriculture; Forestry; Meteorology & Atmospheric Sciences GA 820CQ UT WOS:000221364600002 ER PT J AU Machol, JL Ayers, T Schwenz, KT Koenig, KW Hardesty, RM Senff, CJ Krainak, MA Abshire, JB Bravo, HE Sandberg, SP AF Machol, JL Ayers, T Schwenz, KT Koenig, KW Hardesty, RM Senff, CJ Krainak, MA Abshire, JB Bravo, HE Sandberg, SP TI Preliminary measurements with an automated compact differential absorption lidar for the profiling of water vapor SO APPLIED OPTICS LA English DT Article ID LASERS AB The design and preliminary tests of an automated differential absorption lidar (DIAL) that profiles water vapor in the lower troposphere are presented. The instrument, named CODI (for compact DIAL), has been developed to be eye safe, low cost, weatherproof, and portable. The lidar design and its unattended operation are described. Nighttime intercomparisons with in situ sensors and a radiosonde are shown. Desired improvements to the lidar, including a more powerful laser, are also discussed. (C) 2004 Optical Society of America. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80305 USA. NOAA, Environm Technol Lab, Boulder, CO 80305 USA. Natl Ctr Atmospher Res, Adv Technol Div, Boulder, CO 80307 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Machol, JL (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80305 USA. EM janet.machol@noaa.gov RI Hardesty, Robert/H-9844-2013; Senff, Christoph/I-2592-2013; Abshire, James/I-2800-2013; Sandberg, Scott/I-4875-2013; Machol, Janet/D-5896-2016 OI Machol, Janet/0000-0002-0344-0314 NR 32 TC 32 Z9 33 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 MAY 20 PY 2004 VL 43 IS 15 BP 3110 EP 3121 DI 10.1364/AO.43.003110 PG 12 WC Optics SC Optics GA 822GX UT WOS:000221528200015 PM 15176200 ER PT J AU Hara, H Walsh, BM Barnes, NP AF Hara, H Walsh, BM Barnes, NP TI Tunability of a 946-nm Nd : YAG microchip laser by use of a double-cavity configuration SO APPLIED OPTICS LA English DT Article ID NM AB We observed the tunability of a 946-nm Nd:YAG microchip laser by using a double-cavity configuration. We shifted the lasers wavelength from 938 to 946 nm by changing the thickness of the air gap. In addition, differences in reflectivity of the output mirror yielded the tunable range of the 946-nm band, with the center oscillation wavelength maintained at 946.1 nm. (C) 2004 Optical Society of America. C1 Leadintex Int Inc, Chuo Ku, Tokyo 1030011, Japan. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Hara, H (reprint author), Leadintex Int Inc, Chuo Ku, 1-3 Nihonbashi, Tokyo 1030011, Japan. EM hara@leadin.co.jp NR 12 TC 4 Z9 5 U1 2 U2 2 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 MAY 20 PY 2004 VL 43 IS 15 BP 3171 EP 3173 DI 10.1364/AO.43.003171 PG 3 WC Optics SC Optics GA 822GX UT WOS:000221528200024 PM 15176208 ER PT J AU Dolan, JF Clark, LL AF Dolan, JF Clark, LL TI A search for short-timescale microvariability in active galactic nuclei in the ultraviolet SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 6814, Markarian 205, 3C 249.1, 3C 371); galaxies : Seyfert; ultraviolet : galaxies ID PROBING ACCRETION DISKS; X-RAY SOURCE; BLACK-HOLE; OPTICAL VARIABILITY; SEYFERT-GALAXIES; 3C 371; OBJECTS; DISKOSEISMOLOGY; NGC-6814; SPECTRA AB We observed four active galactic nuclei (AGNs) ( the type 1 Seyfert systems 3C 249.1, NGC 6814, and Mrk 205, and the BL Lac object 3C 371) using the High Speed Photometer on the Hubble Space Telescope (HST) to search for short-timescale microvariability in the UV. Continuous observations of similar to 3000 s duration were obtained for each system on several consecutive HSTorbits using a 1 s sample time in a 1400 - 3000 Angstrom bandpass. No photometric variability greater than 0.3% (0.003 mag) was detected in any AGN on timescales shorter than 1500 s. The distribution of photon arrival times observed from each source was consistent with Poisson statistics. Because of HST optical problems, the limit on photometric variability at longer timescales is less precise. These results restrict the masses of black holes as the central engines of AGNs and the diskoseismic oscillations of any accretion disk around such a black hole. C1 NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. San Diego State Univ, Dept Astron, San Diego, CA 92182 USA. RP Dolan, JF (reprint author), NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 44 TC 1 Z9 1 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2004 VL 607 IS 1 BP 84 EP 89 DI 10.1086/383460 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822FN UT WOS:000221523900008 ER PT J AU Sandford, SA Bernstein, MP Allamandola, LJ AF Sandford, SA Bernstein, MP Allamandola, LJ TI The mid-infrared laboratory spectra of naphthalene (C10H8) in solid H2O SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; ISM : lines and bands; ISM : molecules; line : identification; molecular data ID POLYCYCLIC AROMATIC-HYDROCARBONS; COMETARY ICE ANALOGS; SIDE-GROUP ADDITION; INFRARED-SPECTROSCOPY; ASTROPHYSICAL IMPLICATIONS; ABSORPTION FEATURES; INTERSTELLAR; CATIONS; PROTOSTARS; IRRADIATION AB Polycyclic aromatic hydrocarbons (PAHs) are common throughout the universe. Gas-phase PAHs are easily detected in radiation-rich environments by the characteristic infrared (IR) emission bands they produce when they are excited by higher energy radiation. In contrast, in dense interstellar clouds, where the PAHs could be present as unexcited gas-phase molecules or dust grains or frozen into ice mantles, they are expected to be seen in absorption. We present full mid-IR spectra of the PAH naphthalene (C10H8) in several media to facilitate searches for PAHs in absorption in dense clouds. The positions, widths, and strengths of the absorption bands of naphthalene are significantly altered from the gas phase when it is placed in a matrix, with the extent of the alteration depending on the nature of the matrix interaction. The infrared features of gas-phase naphthalene show P, Q, and R branches characteristic of rovibrational transitions, while naphthalene in condensed forms does not. When condensed in a relatively inert matrix (e.g., Ar or N-2), the IR features produced by naphthalene are narrow (generally FWHM < 2 cm(-1)) and may show multiple components associated with different matrix sites. In more interactive matrices ( e. g., pure naphthalene and H2O), the bands become considerably broader ( factors of 3-10), show small band position shifts (0-10 cm(-1) in either direction), and show variable changes in relative band strengths ( typically factors of 1-3). There is little systematic increase or decrease in the band strengths (perhaps none). In H2O-rich ices, naphthalene bands are relatively insensitive to concentration and temperature, with the exception that all the bands show dramatic changes as the ices are warmed through the temperature range in which amorphous H2O ice converts to its cubic and hexagonal crystalline forms. Given the small observed band shifts (< 10 cm(-1); < 0.04 μm at 6 μm), the current database of spectra from Ar matrix-isolated PAHs should be useful for the search for PAHs in dense clouds on the basis of observed absorption band positions. Furthermore, these data permit determination of column densities to better than a factor of 3 for PAHs in dense clouds. Column density determination of detected aromatics to better than a factor of 3 will, however, require good knowledge about the nature of the matrix in which the PAH is embedded and laboratory studies of relevant samples. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Mountain View, CA 94043 USA. RP Sandford, SA (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. EM scott.sandford@nasa.gov NR 42 TC 30 Z9 30 U1 0 U2 11 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2004 VL 607 IS 1 BP 346 EP 360 DI 10.1086/383461 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822FN UT WOS:000221523900029 ER PT J AU Evans, CJ Lennon, DJ Trundle, C Heap, SR Lindler, DJ AF Evans, CJ Lennon, DJ Trundle, C Heap, SR Lindler, DJ TI Terminal velocities of luminous, early-type stars in the Small Magellanic Cloud SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : early-type; stars : fundamental parameters; stars : winds, outflows; ultraviolet : stars ID B-TYPE SUPERGIANTS; O-TYPE STARS; HST UV SPECTRA; STELLAR WINDS; MASSIVE STARS; LOW METALLICITY; HOT STARS; DRIVEN WINDS; ULTRAVIOLET; SPECTROSCOPY AB Ultraviolet spectra from the Space Telescope Imaging Spectrograph (STIS) are used to determine terminal velocities for 11 O and B-type giants and supergiants in the Small Magellanic Cloud (SMC) from the Si iv and C iv resonance lines. Using archival data from observations with the Goddard High-Resolution Spectrograph and the International Ultraviolet Explorer telescope, terminal velocities are obtained for a further five B-type supergiants. We discuss the metallicity dependence of stellar terminal velocities for supergiants, finding no evidence for a significant scaling between Galactic and SMC metallicities for T-eff < 30,000 K, consistent with the predictions of radiation-driven wind theory. A comparison of the v(&INFIN;)/v(esc) ratio between the SMC and Galactic samples, while consistent with the above statement, emphasizes that the uncertainties in the distances to galactic OB-type stars are a serious obstacle to a detailed comparison with theory. For the SMC sample there is considerable scatter in v(&INFIN;)/v(esc) at a given effective temperature, perhaps indicative of uncertainties in stellar masses. C1 Isaac Newton Grp Telescopes, Santa Cruz De La Palma 38700, Canary Islands, Spain. Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Evans, CJ (reprint author), Isaac Newton Grp Telescopes, Apartado Correos 321, Santa Cruz De La Palma 38700, Canary Islands, Spain. RI heap, sara/E-2237-2012; OI Lennon, Daniel/0000-0003-3063-4867 NR 57 TC 28 Z9 28 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2004 VL 607 IS 1 BP 451 EP 459 DI 10.1086/383306 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822FN UT WOS:000221523900039 ER PT J AU Lynch, DK Rudy, RJ Russell, RW Mazuk, S Venturini, CC Dimpfl, W Bernstein, LS Sitko, ML Fajardo-Acosta, S Tokunaga, A Knacke, R Puetter, RC Perry, RB AF Lynch, DK Rudy, RJ Russell, RW Mazuk, S Venturini, CC Dimpfl, W Bernstein, LS Sitko, ML Fajardo-Acosta, S Tokunaga, A Knacke, R Puetter, RC Perry, RB TI 0.8-13 micron spectroscopy of V838 Monocerotis and a model for its emission SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; nuclear reactions, nucleosynthesis, abundances stars : individual (V838 Monocerotis); stars : variables : other ID CRYSTALLINE SILICATE DUST; EVOLVED STARS; INTERSTELLAR EXTINCTION; INFRARED-SPECTROSCOPY; SAKURAIS-OBJECT; BROWN DWARFS; SPECTRA; ERUPTION; MON; FEATURES AB We report on the results of a number of infrared spectra (0.8-2.5, 2.1-4.6, and 3-14 mum) of V838 Monocerotis, taken from a short time after discovery in 2002 January to about 14 months later, in early 2003. The spectrum evolved dramatically, changing from a quasi-photospheric stellar spectrum with weak atomic emission lines (some with P Cygni profiles) to one showing a wide range of deep absorption features indicative of a cool, extended atmosphere with a circumstellar dust shell. The early spectra showed lines of s-process elements, such as Sr II and Ba I. The later spectra showed absorption by gaseous H2O, CO, AlO, TiO, SiO, SO2, OH, VO, and SH, as well as a complex of emission near 10 mum reminiscent of silicate emission, with a central absorbing feature at 10.3 mum. Thus, V838 Mon appears to be oxygen-rich. A simple, spherically symmetric model of the system involving a central star with a two-component expanding circumstellar shell is presented that is able to explain the major molecular features and spectral energy distribution in the object's late stages. The derived shell mass and distance are 0.04 M. and 9.2 kpc, respectively. C1 Aerosp Corp, Los Angeles, CA 90009 USA. Spectral Sci Inc, Burlington, MA 01803 USA. Univ Cincinnati, Dept Phys, Cincinnati, OH 45221 USA. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Penn State Univ, Sch Sci, Erie, PA 16563 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Pixon LLC, San Diego, CA 92193 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Lynch, DK (reprint author), Aerosp Corp, POB 92957, Los Angeles, CA 90009 USA. NR 52 TC 31 Z9 32 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2004 VL 607 IS 1 BP 460 EP 473 DI 10.1086/382667 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822FN UT WOS:000221523900040 ER PT J AU Gilbert, HR Holzer, TE Thompson, BJ Burkepile, JT AF Gilbert, HR Holzer, TE Thompson, BJ Burkepile, JT TI A comparison of CME-associated atmospheric waves observed in coronal (Fe XII 195 angstrom) and chromospheric (He I 10830 angstrom) lines SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; Sun : chromosphere; Sun : corona; waves ID SOHO/EIT OBSERVATIONS; MASS EJECTION; MORETON WAVES; ALPHA MORETON; FLARE WAVES; EIT WAVES; HELIUM; TRANSIENT; ORIGIN; MODELS AB Although "Moreton" waves have historically been observed in Halpha data, more recently waves have also been observed in chromospheric He I lambda10830 images obtained at the Mauna Loa Solar Observatory. In an effort to better understand the nature of chromospheric waves and their relationship to coronal waves observed in EUV Imaging Telescope (EIT) data, we focus on two events in which waves are observed simultaneously in He I lambda10830 and Fe XII lambda195, lines that are formed in the chromosphere and the corona, respectively. Comparing the waves observed in these two lines allows the determination of the spatial relationship between coronal and chromospheric waves and thus aids in the understanding of the underlying physics of waves in the solar atmosphere. The main goal of this work is to begin an investigation into whether both coronal and chromospheric waves are mechanical (e.g., MHD waves) by looking at their spatial relationship. We find that the chromospheric waves in these two events are cospatial with their coronal counterparts, indicating that they are not mechanical in nature but are chromospheric imprints of mechanical waves propagating through the corona. This conclusion is based on the nature of the formation of the He I absorption line. C1 Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Natl Ctr Atmospher Res, High Altitude Observ, POB 3000, Boulder, CO 80307 USA. EM iggy@ucar.edu; holzer@ucar.edu; iguana@ucar.edu RI Gilbert, Holly/C-7215-2012; Thompson, Barbara/C-9429-2012 NR 30 TC 41 Z9 41 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2004 VL 607 IS 1 BP 540 EP 553 DI 10.1086/383231 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822FN UT WOS:000221523900045 ER PT J AU Sekanina, Z Chodas, PW AF Sekanina, Z Chodas, PW TI Fragmentation hierarchy of bright sungrazing comets and the birth and orbital evolution of the Kreutz system. I. Two-superfragment model SO ASTROPHYSICAL JOURNAL LA English DT Article DE comets : general; comets : individual (X/1106 C1, C/1843 D1, C/1880 C1, C/1882 R1, C/1887 B1, C/1945 X1, C/1963 R1, C/1965 S1, C/1970 K1) methods : data analysis ID SECONDARY FRAGMENTATION; SOLAR; ORIGIN AB A back-and-forth orbit integration technique, developed for our previous investigation of the splitting of the parent of the sungrazers C/1882 R1 and C/1965 S1, is now applied in an effort to understand the history and orbital evolution of the Kreutz sungrazer system, starting with the birth of two subgroups, which show prominently among the bright members and whose inception dates back to the progenitor's breakup into two superfragments. The integration technique is used to reproduce the motion of comet C/1843 D1 - the second brightest sungrazer known and presumably the most massive surviving piece of superfragment I - from the motion of C/1882 R1 - the brightest sungrazer on record and arguably the most massive surviving piece of superfragment II. Running the orbit of C/1882 R1 back to A.D. 326, the progenitor comet is found to have split at a heliocentric distance of 50 AU and nearly 30 yr before perihelion. The superfragments acquired separation velocities of similar to8 m s(-1) in opposite directions. Using the same technique, we show next that (1) the motions of two additional sungrazers, C/1880 C1 and C/1887 B1, are matched extremely well if these objects shared a common parent with C/1843 D1, and (2) C/1963 R1 (Pereyra), the second brightest subgroup I member on record, is more closely related to subgroup II objects (such as C/1882 R1 and C/1965 S1) than to C/1843 D1. This finding raises serious doubts about the major role of the subgroups in the system's orbital history and offers an incentive for considering an alternative dynamical scenario. The fragmentation models for C/1963 R1 and two additional bright sungrazers, C/1945 X1 and C/1970 K1, suggest that (1) these comets may have been the most massive pieces of the fragment populations formed from their respective disintegrating parents, and (2) the course of evolution of the Kreutz system at the upper end of the mass spectrum may be better ascertained from the distribution of the sungrazers' arrival times than from the sources of subgroups. If so, the fragment hierarchy should be determined primarily by the cascading nature of the fragmentation process, which was recently shown by Sekanina to control the evolution of minor fragments as well. The sungrazer system's estimated age is in any case very short, less than 1700 yr. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sekanina, Z (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM zs@sek.jpl.nasa.gov; paul.w.chodas@jpl.nasa.gov NR 43 TC 23 Z9 23 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2004 VL 607 IS 1 BP 620 EP 639 DI 10.1086/383466 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 822FN UT WOS:000221523900052 ER PT J AU Gao, FG Jeevarajan, AS Anderson, MM AF Gao, FG Jeevarajan, AS Anderson, MM TI Long-term continuous monitoring of dissolved oxygen in cell culture medium for perfused bioreactors using optical oxygen sensors SO BIOTECHNOLOGY AND BIOENGINEERING LA English DT Article DE pO(2) (partial pressure of oxygen); dissolved oxygen; optical sensor; tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II); chloride; cell culture; BHK-21 cells ID LINEAR CALIBRATION FUNCTION; FLUORESCENCE MICROSCOPY; RUTHENIUM; COMPLEXES; FIBER; PROBE; TIME AB For long-term growth of mammalian cells in perfused bioreactors, it is essential to monitor the concentration of dissolved oxygen (DO) present in the culture medium to ascertain the health of the cells. An optical oxygen sensor based on dynamic fluorescent quenching was developed for long-term continuous measurement of DO for NASA-designed rotating perfused bioreactors. Tris(4,7diphenyl-1,10-phenanthroline) ruthenium(II) chloride is employed as the fluorescent dye indicator. A pulsed, blue LED was chosen as the excitation light source. The sensor can be sterilized using an autoclave. The sensors were tested in a perfused rotating bioreactor supporting a BHK-21 (baby hamster kidney) cell culture over one 28-day, one 43-day, and one 180-day cell runs. The sensors were initially calibrated in sterile phosphate-buffered saline (PBS) against a blood-gas analyzer (BGA), and then used continuously during the entire cell culture without recalibration. In the 180-day cell run, two oxygen sensors were employed; one interfaced at the outlet of the bioreactor and the other at the inlet of the bioreactor. The DO concentrations determined by both sensors were compared with those sampled and measured regularly with the BGA reference. The sensor outputs were found to correlate well with the BGA data throughout the experiment using a single calibration, where the DO of the culture medium varied between 25 and 60 mm Hg at the bioreactor outlet and 80-116 mm Hg at the bioreactor inlet. During all 180 days of culture, the precision and the bias were +/- 5.1 mm Hg and - 3.8 mm Hg at the bioreactor outlet, and 19 mm Hg and - 18 mm Hg at inlet. The sensor dynamic range is between 0 and 200 mm Hg and the response time is less than 1 minute. The resolution of the sensor is 0.1 mm Hg at 50 mm Hg, and 0.25 mm Hg at 130 mm Hg. (C) 2004 Wiley Periodicals, Inc. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Wyle Labs, Life Sci Syst & Serv, Houston, TX 77058 USA. RP Jeevarajan, AS (reprint author), NASA, Lyndon B Johnson Space Ctr, 2101 NASA Rd 1,Mail Code SJ, Houston, TX 77058 USA. EM antony.s.jeevarajan@nasa.gov NR 33 TC 30 Z9 31 U1 1 U2 9 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 0006-3592 J9 BIOTECHNOL BIOENG JI Biotechnol. Bioeng. PD MAY 20 PY 2004 VL 86 IS 4 BP 425 EP 433 DI 10.1002/bit.20010 PG 9 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 816NV UT WOS:000221117500006 PM 15112295 ER PT J AU Soja, AJ Sukhinin, AI Cahoon, DR Shugart, HH Stackhouse, PW AF Soja, AJ Sukhinin, AI Cahoon, DR Shugart, HH Stackhouse, PW TI AVHRR-derived fire frequency, distribution and area burned in Siberia SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID BOREAL FOREST-FIRES; HIGH-RESOLUTION RADIOMETER; CLIMATE-CHANGE; WILDFIRE; SEASON; EMISSIONS; SAVANNA; CHANNEL; BIOMASS; CANADA AB Advanced Very High Resolution Radiometer (AVHRR) data are used to produce an active-fire detection product for the fire season in 1999 and 2000 and an area burned product for 1996-2000. The distribution of fire is presented ranging from the Urals in the west to the eastern coast and from the semi-dry steppe regions in the south through the taiga in the north. A temporal and spatial pattern of fire is observed migrating from north of 40degrees N latitude in April to north of 60degrees N by mid-July. Fire is widespread in August, spanning the entire geographic range. In contrast to these patterns, no similar east-west migrations are discernible from these data. Peak active-fire counts are detected in early May between 50 and 55degrees N latitude in both 1999 and 2000. Wildfire in Russia is highly variable, both annually and interannually, with differences in reported area burned ranging from 0.234 to 13.3 million hectares per year. Comparing Russian fire statistics to satellite-based data from this investigation and previous works, we find area burned in Russia may be commonly underestimated by an average of 213%. Underestimates of this magnitude could strongly affect emissions estimates and climate change research. C1 Univ Virginia, Dept Environm Sci, Charlottesville, VA 22903 USA. Russian Acad Sci, Sukachev Forest Inst, Krasnoyarsk 660036, Russia. Terra Syst Res, Williamsburg, VA 23185 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Soja, AJ (reprint author), Univ Virginia, Dept Environm Sci, Clark Hall, Charlottesville, VA 22903 USA. EM a.j.soja@larc.nasa.gov RI Shugart, Herman/C-5156-2009 NR 70 TC 47 Z9 53 U1 0 U2 9 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD MAY 20 PY 2004 VL 25 IS 10 BP 1939 EP 1960 DI 10.1080/01431160310001609725 PG 22 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 810QJ UT WOS:000220718500009 ER PT J AU Oltmans, SJ Johnson, BJ Harris, JM Thompson, AM Liu, HY Chan, CY Vomel, H Fujimoto, T Brackett, VG Chang, WL Chen, JP Kim, JH Chan, LY Chang, HW AF Oltmans, SJ Johnson, BJ Harris, JM Thompson, AM Liu, HY Chan, CY Vomel, H Fujimoto, T Brackett, VG Chang, WL Chen, JP Kim, JH Chan, LY Chang, HW TI Tropospheric ozone over the North Pacific from ozonesonde observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE tropospheric ozone; biomass burning; stratosphere/troposphere exchange ID HONG-KONG; SEASONAL VARIABILITY; TRANSPORT PATHWAYS; CLIMATOLOGY; EXCHANGE; MODEL; PATTERNS; PROJECT; PROFILE; ASIA AB [ 1] As part of the Transport and Chemical Evolution over the Pacific (TRACE-P) mission, ozonesondes were used to make ozone vertical profile measurements at nine locations in the North Pacific. At most of the sites there is a multiyear record of observations. From locations in the western Pacific ( Hong Kong; Taipei; Jeju Island, Korea; and Naha, Kagoshima, Tsukuba, and Sapporo, Japan), a site in the central Pacific ( Hilo, Hawaii), and a site on the west coast of the United States ( Trinidad Head, California) both a seasonal and event specific picture of tropospheric ozone over the North Pacific emerges. Ozone profiles over the North Pacific generally show a prominent spring maximum throughout the troposphere. This maximum is tied to the location of the jet stream and its influence on stratosphere-troposphere exchange and the increase in photochemical ozone production through the spring. Prominent layers of enhanced ozone in the middle and upper troposphere north of about 30degrees N seem to be more closely tied to stratospheric intrusions while biomass burning leads to layers of enhanced ozone in the lower and upper troposphere at Hong Kong (22 degreesN) and Taipei (25 degreesN). The lower free tropospheric layers at Hong Kong are associated with burning in SE Asia, but the upper layer may be associated with either equatorial Northern Hemisphere burning in Africa or SE Asian biomass burning. In the boundary layer at Taipei very high mixing ratios of ozone were observed that result from pollution transport from China in the spring and local urban pollution during the summer. At the ozonesonde site near Tokyo ( Tsukuba, 36 degreesN) very large enhancements of ozone are seen in the boundary layer in the summer that are characteristic of urban air pollution. At sites in the mid and eastern Pacific the signature of transport of polluted air from Asia is not readily identifiable from the ozonesonde profile. This is likely due to the more subtle signal and the fact that from the ozone profile and meteorological data by themselves it is difficult to identify such a signal. During the TRACE-P intensive campaign period (February - April 2001), tropospheric ozone amounts were generally typical of those seen in the long-term records of the stations with multiyear soundings. The exception was the upper troposphere over Hong Kong and Taipei where ozone amounts were lower in 2001. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Inst Aerosp, Hampton, VA 23666 USA. Hong Kong Polytech Univ, Dept Civil & Struct Engn, Hong Kong, Hong Kong, Peoples R China. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO USA. Japan Meteorol Agcy, Div Atmospher Environm, Chiyoda Ku, Tokyo 1008122, Japan. NASA, Langley Res Ctr, Sci Applicat Int Corp, Hampton, VA 23681 USA. Hong Kong Observ, Kowloon, Hong Kong, Peoples R China. Natl Taiwan Univ, Dept Atmospher Sci, Taipei 106, Taiwan. Pusan Natl Univ, Dept Atmospher Sci, Pusan 609735, South Korea. Cent Weather Bur, Taipei 100, Taiwan. RP NOAA, Climate Monitoring & Diagnost Lab, 325 Broadway, Boulder, CO 80303 USA. EM samuel.j.oltmans@noaa.gov; bryan.johnson@noaa.gov; joyce.m.harris@noaa.gov; thompson@gatorl.gsfc.nasa.gov; hyl@nianet.org; cececychan@polyu.edu.hk; holger.voemel@noaa.gov; fujimoto@met.kishou.go.jp; vince.g.brackett@nasa.gov; wlchang@hko.gov.hk; jpchen@water.as.ntu.edu.tw; jaekim@subunim.com; celychan@polyu.edu.hk; hsiuwu@cwb.gov.tw RI Liu, Hongyu/A-5867-2008; Chen, Jen-Ping/F-2947-2010; Thompson, Anne /C-3649-2014 OI Chen, Jen-Ping/0000-0003-4188-6189; Thompson, Anne /0000-0002-7829-0920 NR 33 TC 30 Z9 31 U1 1 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 2004 VL 109 IS D15 AR D15S01 DI 10.1029/2003JD003466 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 823KU UT WOS:000221611700001 ER PT J AU Yuan, DL Rienecker, MM Schopf, PS AF Yuan, DL Rienecker, MM Schopf, PS TI Long wave dynamics of the interannual variability in a numerical hindcast of the equatorial Pacific Ocean circulation during the 1990s SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE equatorial wave; interannual variability; numerical hindcast ID 1997-98 EL-NINO; 1993-1998 TOPEX/POSEIDON PERIOD; SOUTHERN-OSCILLATION; WESTERN PACIFIC; ZONAL CURRENTS; SEA-LEVEL; SEASONAL CYCLE; ROSSBY WAVES; KELVIN WAVE; WARM POOL AB A numerical hindcast of the Pacific Ocean circulation for the period of 1988-1998 is conducted to study the dynamics of interannual variations in the 1990s. The Poseidon quasi-isopycnal ocean model is forced with an SSMI-derived wind stress product and sea surface heat flux from an atmospheric mixed layer model. On the basis of a good comparison of the hindcast results with TAO mooring observations, the roles of the propagation and reflection of the equatorial Kelvin and Rossby waves in the evolution of El Nino and La Nina events in the 1990s are investigated. The linear waves are extracted from the nonlinear model in such a way as to preserve model nonlinearity so that the validity of linear theory of the wave propagation and reflection at the western and eastern boundaries can be examined. It is found that the reflection of the Kelvin waves at the eastern boundary is in very good agreement with a linear reflection at a straight meridional wall. In contrast, the reflection of the Rossby waves at the Pacific western boundary is significantly different from linear theory. Besides the validation of linear theory, the decomposition also shows marked differences from altimetry data analyses. Since the hindcast solution is dynamically consistent and close to observations, a significant part of the differences is attributed to errors associated with the incomplete ( least squares fit) wave decomposition from the altimetry data. On the basis of the wave decomposition, the dynamics of the simulated El Nino and La Nina events in the 1990s are compared with three ENSO paradigms. The investigation shows that precursive Rossby waves, important in the Delayed Oscillator paradigm, played an important role in the termination of the 1991-1993 and the 1997-1998 El Nino events. Reflected Rossby waves from the Pacific eastern boundary, the primary negative feedback in the Advective-Reflective paradigm, were present during the termination of the 1994-1995 and the 1997-1998 El Nino. The Western Pacific Oscillator is at best at work during the decay of the 1997 1998 El Nino; however, it played a minor role compared with the other paradigms. None of the three paradigms appears to describe the termination of the 1988-1989 and the 1995-1996 La Nina events and the onset of the 1997-1998 El Nino event well. C1 NASA, Goddard Earth Sci & Technol Ctr, Goddard Space Flight Ctr, Lab Hydrosper Proc,Univ Maryland Baltimore Cty, Greenbelt, MD 20771 USA. George Mason Univ, Climate Dynam Program, Sch Computat Sci, Fairfax, VA 22030 USA. RP Yuan, DL (reprint author), NASA, Goddard Earth Sci & Technol Ctr, Goddard Space Flight Ctr, Lab Hydrosper Proc,Univ Maryland Baltimore Cty, Code 971, Greenbelt, MD 20771 USA. EM dyuan@janus.gsfc.nasa.gov; rienecke@mohawk.gsfc.nasa.gov; schopf@cola.iges.org NR 53 TC 8 Z9 9 U1 2 U2 6 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 MAY 20 PY 2004 VL 109 IS C5 AR C05019 DI 10.1029/2003JC001936 PG 17 WC Oceanography SC Oceanography GA 823KY UT WOS:000221612200001 ER PT J AU Aharonson, O Zuber, MT Smith, DE Neumann, GA Feldman, WC Prettyman, TH AF Aharonson, O Zuber, MT Smith, DE Neumann, GA Feldman, WC Prettyman, TH TI Depth, distribution, and density of CO2 deposition on Mars SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE CO2; deposition; Mars ID GENERAL-CIRCULATION MODEL; ORBITER LASER ALTIMETER; SOUTH POLAR-CAP; WATER-ICE; SUMMER TEMPERATURES; VIKING OBSERVATIONS; MARTIAN ATMOSPHERE; GLOBAL SURVEYOR; CARBON-DIOXIDE; GRAVITY-FIELD AB Observations by the Mars Orbiter Laser Altimeter have been used to detect subtle changes of the polar surface height during the course of seasonal cycles that correlate with the expected pattern of CO2 deposition and sublimation. Using altimetric crossover residuals from the Mars Orbiter Laser Altimeter, we show that while zonally averaged data capture the global behavior of CO2 exchange, there is a dependence of the pattern on longitude. At the highest latitudes the surface height change is as high as 1.5-2 m peak to peak, and it decreases equatorward. Decomposition of the signal into harmonics in time allows inspection of the spatial pattern and shows that the annual component is strongly correlated with the residual south polar cap deposits and, to a lesser extent, with the north polar cap. In the north, the second harmonic (semiannual) component correlates with the location of the ice deposits. The phases of the annual cycles are in agreement with observations by the Thermal Emission Spectrometer of the timing of the annual disappearance of CO2 frost from the surface at the high latitudes. At lower latitudes, frost sublimation ("Crocus date'') predates the mean depositional minima, as expected. These global-scale, volumetric measurements of the distribution of condensed CO2 can be combined with measurements of the deposited column mass density derived from the Neutron Spectrometer on board Mars Odyssey to yield an estimate of the density of the seasonally exchanging material of 0.5 +/- 0.1 g/cm(3). These constraints should be considered in models of the Martian climate system and volatile cycles. C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Aharonson, O (reprint author), CALTECH, Div Geol & Planetary Sci, MC 150-21, Pasadena, CA 91125 USA. EM oa@caltech.edu; zuber@mit.edu; dsmith@tharsis.gsfc.nasa.gov; neumann@tharsis.gsfc.nasa.gov; wfeldman@lanl.gov; thj@lanl.gov RI Neumann, Gregory/I-5591-2013; OI Neumann, Gregory/0000-0003-0644-9944; Prettyman, Thomas/0000-0003-0072-2831 NR 59 TC 34 Z9 35 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 20 PY 2004 VL 109 IS E5 AR E05004 DI 10.1029/2003JE002223 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 823LC UT WOS:000221612700001 ER PT J AU Gudipati, MS AF Gudipati, MS TI Matrix-isolation in cryogenic water-ices: Facile generation, storage, and optical spectroscopy of aromatic radical cations SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID OUTER SOLAR-SYSTEM; ELECTRONIC SPECTROSCOPY; HYDROCARBON CATIONS; RARE-GAS; ULTRAVIOLET PHOTOLYSIS; INFRARED-SPECTROSCOPY; ABSORPTION-SPECTRA; ORGANIC-MOLECULES; EXCITED-STATES; AMINO-ACIDS AB Radical cations of naphthalene and 4-methylpyrene have been generated for the first time in high conversion efficiencies in cryogenic water-ices at 15 K through vacuum ultraviolet photolysis. With these radical cations as probes it is shown that cryogenic water-ices at temperatures below 50 K are of good optical quality and inert matrices to isolate and study the electronic spectroscopic properties of neutral and ionic species in the wavelength region 250-900 nm. The spectral energies of guest-species in the cryogenic water-ices are closely comparable with those observed using rare-gas matrices, indicating similar host-guest interactions in rare-gas matrices and water-ices below 50 K. The radical cations are converted to the corresponding alcohols at temperatures higher than 50 K due to reactions between the host and ionized guest species. Thus, cryogenic water-ices are inert matrices that resemble and complement the rare-gas matrices in many aspects. Efficient ionization of organic molecules, such as PAHs studied here, in water-rich ices indicates that ionization-mediated processes play an important role in the evolution of cosmic ices that are exposed to ionizing radiation. C1 Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Cologne, Inst Phys Chem, Cologne, Germany. RP Gudipati, MS (reprint author), Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. EM gudipati@glue.umd.edu RI Gudipati, Murthy/F-7575-2011 NR 71 TC 23 Z9 23 U1 1 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 20 PY 2004 VL 108 IS 20 BP 4412 EP 4419 DI 10.1021/jp037152b PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 821IU UT WOS:000221454500007 ER PT J AU Chaban, GM AF Chaban, GM TI Anharmonic vibrational spectroscopy of nitriles and their complexes with water SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID SELF-CONSISTENT-FIELD; AB-INITIO; EMPIRICAL POTENTIALS; SYSTEMS; GLYCINE; STATES; AMINOACETONITRILE; CLUSTERS; (H2O)(N); SPECTRA AB Three nitrile molecules, cyanamide (H(2)N-Cequivalent toN), acetonitrile (CH(3)-Cequivalent toN), and aminoacetonitrile (H(2)N-CH(2)-Cequivalent toN), and their complexes with one water molecule are studied at the ab initio level of theory (second-order Moller-Plesset perturbation theory with triple-xi basis sets). Anharmonic vibrational spectra are estimated with the Correlation Corrected Vibrational Self-Consistent Field (CC-VSCF) method that accounts for anharmonicities and couplings between different vibrational normal modes. Effects of complexation with water on geometries and vibrational spectra of nitriles are investigated. The effects are very different from those found earlier for acids (in particular, the amino acid glycine). While the intermolecular hydrogen bonding interactions lead to significant red shifts of carboxyl group (O-H and C=O) vibrational stretching frequencies of acids, Cequivalent toN stretches of nitriles shift to a much lesser extent and in the opposite direction (to the blue) upon complexation with water. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Chaban, GM (reprint author), NASA, Ames Res Ctr, Mail Stop T27B-1, Moffett Field, CA 94035 USA. EM chaban@nas.nasa.gov NR 16 TC 27 Z9 27 U1 2 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 20 PY 2004 VL 108 IS 20 BP 4551 EP 4556 DI 10.1021/jp049704b PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 821IU UT WOS:000221454500025 ER PT J AU Kug, JS Kang, IS Lee, JY Jhun, JG AF Kug, JS Kang, IS Lee, JY Jhun, JG TI A statistical approach to Indian Ocean sea surface temperature prediction using a dynamical ENSO prediction SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID INTERMEDIATE OCEAN; VARIABILITY; MONSOON AB In this study, a statistical prediction model has been developed to forecast monthly Sea Surface Temperature (SST) in the Indian Ocean. It is a linear regression model based on a lagged relationship between the Indian Ocean SST and the NINO3 SST. A new approach to the statistical modeling has been tried out, in which the model predictors are obtained from not only observed NINO3 SST but also predicted results produced by a dynamical El Nino model. The forecast skill of the present model is better than that of persistence prediction. In particular, the present model has a significantly improved predictive skill during the spring and summer seasons when the boreal summer Indian monsoon is affected by the Indian Ocean SST. C1 Seoul Natl Univ, Sch Earth & Environm Sci, Seoul 151742, South Korea. NASA, Goddard Space Flight Ctr, Lab Atmosphere, Greenbelt, MD 20771 USA. Seoul Natl Univ, Climate Environm Syst Res Ctr, Seoul, South Korea. RP Kug, JS (reprint author), Seoul Natl Univ, Sch Earth & Environm Sci, Seoul 151742, South Korea. EM jskug@climate.snu.ac.kr; kang@climate.snu.ac.kr RI Lee, June-Yi/D-5752-2012; KUG, JONG-SEONG/A-8053-2013; 안, 민섭/D-9972-2015 NR 12 TC 12 Z9 14 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 MAY 15 PY 2004 VL 31 IS 9 AR L09212 DI 10.1029/2003GL019209 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 821PH UT WOS:000221473700001 ER PT J AU Zhai, HJ Wang, LS Jena, P Gutsev, GL Bauschlicher, CW AF Zhai, HJ Wang, LS Jena, P Gutsev, GL Bauschlicher, CW TI Competition between linear and cyclic structures in monochromium carbide clusters CrCn- and CrCn (n=2-8): A photoelectron spectroscopy and density functional study SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ELECTRONIC POPULATION ANALYSIS; MOLECULAR WAVE FUNCTIONS; GAUSSIAN-BASIS SETS; TRANSITION-METAL CLUSTERS; SMALL CHROMIUM CLUSTERS; CARBON CLUSTERS; AB-INITIO; THERMODYNAMIC PROPERTIES; ABINITIO CALCULATIONS; CORRELATION-ENERGY AB Photoelectron spectroscopy (PES) is combined with density functional theory (DFT) to study the monochromium carbide clusters CrCn- and CrCn (n=2-8). Well-resolved PES spectra were obtained, yielding structural, electronic, and vibrational information about both the anionic and neutral clusters. Experimental evidence was observed for the coexistence of two isomers for CrC2-, CrC3-, CrC4-, and CrC6-. Sharp and well-resolved PES spectra were observed for CrCn- (n=4,6,8), whereas broad spectra were observed for CrC5- and CrC7-. Extensive DFT calculations using the generalized gradient approximation were carried out for the ground and low-lying excited states of all the CrCn- and CrCn species, as well as coupled-cluster calculations for CrC2- and CrC2. Theoretical electron affinities and vertical detachment energies were calculated and compared with the experimental data to help the assignment of the ground states and obtain structural information. We found that CrC2- and CrC3- each possess a close-lying cyclic and linear structure, which were both populated experimentally. For the larger CrCn- clusters with n=4, 6, 8, linear structures are the overwhelming favorite, giving rise to the sharp PES spectral features. CrC7- was found to have a cyclic structure. The broad PES spectra of CrC5- suggested a cyclic structure, whereas the DFT results predicted a linear one. (C) 2004 American Institute of Physics. C1 Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. Virginia Commonwealth Univ, Dept Phys, Richmond, VA 23284 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Zhai, HJ (reprint author), Washington State Univ, Dept Phys, Richland, WA 99352 USA. EM ls.wang@pnl.gov NR 81 TC 46 Z9 48 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 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 15 PY 2004 VL 120 IS 19 BP 8996 EP 9008 DI 10.1063/1.1701754 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 816YY UT WOS:000221146400013 PM 15267835 ER PT J AU Worden, J Kulawik, SS Shephard, MW Clough, SA Worden, H Bowman, K Goldman, A AF Worden, J Kulawik, SS Shephard, MW Clough, SA Worden, H Bowman, K Goldman, A TI Predicted errors of tropospheric emission spectrometer nadir retrievals from spectral window selection SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE remote sensing; troposphere; error characterization ID MICROWINDOWS; SATELLITE; SOUNDERS; METHANE; HITRAN; OZONE AB Error covariances and vertical resolutions are reported for Tropospheric Emission Spectrometer (TES) nadir-view retrievals of surface temperature, atmospheric temperature, H2O, O-3, CO, and CH4. These error covariances are computed as a result of selecting spectral windows that maximize the information content of simulated, TES nadir-view atmospheric retrievals of four regions representative of northern midlatitude, southern midlatitude, tropical, and polar climates. The information content of a retrieval is a function of an a priori and an a posteriori covariance matrix where the a posteriori covariance depends on an estimated smoothing error, measurement error, and systematic errors from interfering species, surface emissivity, atmospheric and surface temperature, and line parameter uncertainties. For conditions representative of northern midlatitudes, we can expect about 3 degrees of freedom (DOF) for retrievals of H2O, 5 DOF for O-3 with about 2.4 DOF in the troposphere, and 0.8 DOF for CO. These measures for the vertical resolution and the predicted errors can be used to assess which atmospheric science questions can be addressed with TES atmospheric retrievals. Proper characterization of TES retrievals is also critical for applications such as atmospheric data assimilation and inverse modeling. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Atmospher & Environm Res Inc, Lexington, MA 02421 USA. Univ Denver, Dept Phys, Denver, CO 80208 USA. RP Worden, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM john.worden@jpl.nasa.gov NR 18 TC 102 Z9 103 U1 0 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 15 PY 2004 VL 109 IS D9 AR D09308 DI 10.1029/2004JD004522 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 821PN UT WOS:000221474400004 ER PT J AU Liu, X Newchurch, MJ Loughman, R Bhartia, P AF Liu, X Newchurch, MJ Loughman, R Bhartia, P TI Errors resulting from assuming opaque Lambertian clouds in TOMS ozone retrieval SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE ozone retrieval; TOMS; cloud; opaque Lambertian clouds ID OXYGEN A-BAND; TROPOSPHERIC OZONE; BIDIRECTIONAL REFLECTANCE; MAPPING SPECTROMETER; OPTICAL-THICKNESS; UV MEASUREMENTS; WATER CLOUDS; TOP PRESSURE; SCATTERING; CONVECTION AB Accurate remote sensing retrieval of atmospheric constituents over cloudy areas is very challenging because of insufficient knowledge of cloud parameters. Cloud treatments are highly idealized in most retrieval algorithms. Using a radiative transfer model treating clouds as scattering media, we investigate the effects of assuming opaque Lambertian clouds and employing a Partial Cloud Model (PCM) on Total Ozone Mapping Spectrometer (TOMS) ozone retrievals, especially for tropical high-reflectivity clouds. Assuming angularly independent cloud reflection is good because the Ozone Retrieval Errors (OREs) are within 1.5% of the total ozone (i.e., within TOMS retrieval precision) when Cloud Optical Depth (COD) greater than or equal to 20. Because of Intra-Cloud Ozone Absorption ENhancement (ICOAEN), assuming opaque clouds can introduce large OREs even for optically thick clouds. For a water cloud of COD 40 spanning 2-12 km with 20.8 Dobson Unit (DU) ozone homogeneously distributed in the cloud, the ORE is 17.8 DU in the nadir view. The ICOAEN effect depends greatly on solar zenith angle, view zenith angle, and intra-cloud ozone amount and distribution. The TOMS PCM is good because negative errors from the cloud fraction being underestimated partly cancel other positive errors. At COD less than or equal to, 5, the TOMS algorithm retrieves approximately the correct total ozone because of compensating errors. With increasing COD up to 20-40, the overall positive ORE increases and is finally dominated by the ICOAEN effect. The ICOAEN effect is typically 5-13 DU on average over the Atlantic and Africa and 1-7 DU over the Pacific for tropical high-altitude (cloud top pressure less than or equal to 300 hPa) and high-reflectivity (reflectivity greater than or equal to 80%) clouds. Knowledge of TOMS ozone retrieval errors has important implications for remote sensing of ozone/trace gases from other satellite instruments. (C) 2003 Elsevier Ltd. All rights reserved. C1 Univ Alabama, Dept Atmospher Sci, Huntsville, AL 35805 USA. Univ Arizona, Cooperat Ctr Atmospher Sci & Technol, Tucson, AZ 85721 USA. NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Greenbelt, MD 20771 USA. RP Newchurch, MJ (reprint author), Univ Alabama, Dept Atmospher Sci, 320 Sparkman Dr, Huntsville, AL 35805 USA. EM mike@nsstc.uah.edu RI Liu, Xiong/P-7186-2014; Bhartia, Pawan/A-4209-2016 OI Liu, Xiong/0000-0003-2939-574X; Bhartia, Pawan/0000-0001-8307-9137 NR 50 TC 22 Z9 22 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 MAY 15 PY 2004 VL 85 IS 3-4 BP 337 EP 365 DI 10.1016/S0022-4073(03)00231-0 PG 29 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 804YZ UT WOS:000220335300006 ER PT J AU Wang, YJ Woodcock, CE Buermann, W Stenberg, P Voipio, P Smolander, H Hame, T Tian, YH Hu, JN Knyazikhin, Y Myneni, RB AF Wang, YJ Woodcock, CE Buermann, W Stenberg, P Voipio, P Smolander, H Hame, T Tian, YH Hu, JN Knyazikhin, Y Myneni, RB TI Evaluation of the MODIS LAI algorithm at a coniferous forest site in Finland SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE MODIS LAI; coniferous forest site; Finland ID LEAF-AREA INDEX; PHOTOSYNTHETICALLY ACTIVE RADIATION; HIERARCHICAL SCENE MODELS; THEMATIC MAPPER; LANDSAT TM; MULTISCALE ANALYSIS; SPECTRAL RESPONSE; OREGON TRANSECT; CANOPY CLOSURE; ABSORBED PAR AB Leaf area index (LAI) collected in a needle-leaf forest site near Ruokolahti, Finland, during a field campaign in June 14-21, 2000, was used to validate Moderate Resolution Imaging Spectroradiometer (MODIS) LAI algorithm. The field LAI data was first related to 30-m resolution Enhanced Thermal Mapper Plus (ETM+) images using empirical methods to create a high-resolution LAI map. The analysis of empirical approaches indicates that preliminary segmentation of the image followed by empirical modeling with the resulting patches, was an effective approach to developing an LAI validation surface. Comparison of the aggregated high-resolution LAI map and corresponding MODIS LAI retrievals suggests satisfactory behavior of the MODIS LAI algorithm although variation in MODIS LAI product is higher than expected. The MODIS algorithm, adjusted to high resolution, generally overestimates the LAI due to the influence of the understory vegetation. This indicates the need for improvements in the algorithm. An improved correlation between field measurements and the reduced simple ratio (RSR) suggests that the shortwave infrared (SWIR) band may provide valuable information for needle-leaf forests. (C) 2004 Elsevier Inc. All rights reserved. C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. Univ Helsinki, Dept Forest Ecol, FIN-00014 Helsinki, Finland. Finnish Forest Res Inst, Suonenjoki Res Stn, FIN-77600 Suonenjoki, Finland. RP Wang, YJ (reprint author), Univ Maryland, Goddard Earth Sci & Technol Ctr, 1450 S Rolling Rd,Rm 3-002, Baltimore, MD 21227 USA. EM yujie@umbc.edu RI Myneni, Ranga/F-5129-2012 NR 48 TC 155 Z9 168 U1 2 U2 21 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAY 15 PY 2004 VL 91 IS 1 BP 114 EP 127 DI 10.1016/j.rsc.2004.02.007 PG 14 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 828XB UT WOS:000222005900008 ER PT J AU Orphan, VJ Ussler, W Naehr, TH House, CH Hinrichs, KU Paull, CK AF Orphan, VJ Ussler, W Naehr, TH House, CH Hinrichs, KU Paull, CK TI Geological, geochemical, and microbiological heterogeneity of the seafloor around methane vents in the Eel River Basin, offshore California SO CHEMICAL GEOLOGY LA English DT Article DE anaerobic oxidation of methane; cold seep; authigenic carbonate; carbon isotopes; fluorescent in situ hybridization; ether lipids; archaea ID ANOXIC MARINE-SEDIMENTS; GULF-OF-MEXICO; NORTHERN CALIFORNIA; ANAEROBIC OXIDATION; BLACK-SEA; SUBMARINE GEOMORPHOLOGY; CONTINENTAL-MARGIN; SULFATE REDUCTION; VESICOMYID CLAMS; SUBDUCTION ZONE AB Marine methane vents and cold seeps are common features along continental margins worldwide, serving as localized sites for methane release and colonization by microbial and chemosynthetic megafaunal communities. The Eel River Basin (ERB), located on the continental slope off Northern California, contains active methane vents and seep-associated chemosynthetic biological communities (CBC) on the crests of anticlines in similar to 520-m water depth. Seep-related features on the seafloor have a patchy distribution and include active bubbling vents, chemosynthetic clam beds, and sulfide-oxidizing bacterial mats. Methane sources supplying local seeps are heterogeneous on all spatial scales and support a large and diverse microbial assemblage involved in the anaerobic oxidation of methane (AOM). To develop a comprehensive understanding of the complex biological, geochemical and physical processes associated with, and influencing seafloor methane seepage, a multidisciplinary approach is required. Here we present an integrative, multidisciplinary study that illustrates the diverse processes associated with seafloor methane seepage within the Eel River Basin and the complex interactions defining the geochemistry, mineralogy and microbiology within this environment. (C) 2004 Elsevier B.V. All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Montery Bay Aquarium Res Inst, Moss Landing, CA 95039 USA. Texas A&M Univ, Dept Phys & Life Sci, Corpus Christi, TX 78412 USA. Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. Woods Hole Oceanog Inst, Dept Geol & Geophys, Woods Hole, MA 02543 USA. RP Orphan, VJ (reprint author), NASA, Ames Res Ctr, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM vorphan@mail.are.nasa.gov RI Naehr, Thomas/C-2958-2008; Hinrichs, Kai-Uwe/C-7675-2009; Orphan, Victoria/K-1002-2014 OI Hinrichs, Kai-Uwe/0000-0002-0739-9291; Orphan, Victoria/0000-0002-5374-6178 NR 73 TC 70 Z9 76 U1 1 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2541 J9 CHEM GEOL JI Chem. Geol. PD MAY 14 PY 2004 VL 205 IS 3-4 BP 265 EP 289 DI 10.1016/j.chemgeo.2003.12.035 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 820JF UT WOS:000221384300006 ER PT J AU Terrell, CA Hansen, DL Ajello, JM AF Terrell, CA Hansen, DL Ajello, JM TI The near-ultraviolet and visible emission spectrum of O-2 by electron impact SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID CROSS-SECTIONS; DISSOCIATIVE EXCITATION; NEGATIVE BAND; SYSTEM; LYMAN; N-2; IONIZATION; MOLECULES; OXYGEN; H-2 AB The calibrated, optically thin emission spectrum Of 02 gas from 2220 to 6600 A was measured in a crossed-beam experiment with a 100 eV electron beam. The low resolution spectrum (4.6 Angstrom FWHM) includes emission features from the first (b (4)Sigma(g)(-) --> a(4)Pi(u)) and second (A(2)Pi(u) --> X-2 Pi(g)) negative band systems of O-2(+) as well as from O I and O II atomic dissociation products. The excited atomic fragments are found in high lying states that contribute to the strong UV multiplets via cascading. Emission cross sections were obtained for these atomic and molecular features and compared to previous work. The excitation function for the (1, 0) vibrational transition in the first negative band was obtained from the threshold to 400 eV. The excitation functions for the first and second negative band systems are presented in analytic form. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM jajello@pop.jpl.nasa.gov NR 26 TC 5 Z9 5 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 EI 1361-6455 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD MAY 14 PY 2004 VL 37 IS 9 BP 1931 EP 1949 AR PII S0953-4075(04)74636-2 DI 10.1088/0953-4075/37/9/013 PG 19 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 826MR UT WOS:000221833700015 ER PT J AU Prokoph, A Rampino, MR El Bilali, H AF Prokoph, A Rampino, MR El Bilali, H TI Periodic components in the diversity of calcareous plankton and geological events over the past 230 Myr SO PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY LA English DT Article DE planktonic foraminifera; calcareous nannoplankton; diversity; evolution; cycles; time-series analysis ID MASS EXTINCTIONS; TRIASSIC BOUNDARY; COMETARY IMPACTS; WAVELET ANALYSIS; CARBON-CYCLE; TIME-SCALE; CLIMATE; EVOLUTION; RHYTHMS; RECORD AB We performed statistical analysis on high-resolution records of the diversity of calcareous plankton (planktonic foraminifera and calcareous nannoplankton), and on records of global sea level, marine isotopes (delta(18)O delta(13)C Sr-87/Sr-86), large igneous province (LIP) eruptions, and dated impact craters over the last 230 Myr. Results of Continuous Wavelet Analysis (CWT), Fast Fourier Transform (FFT) spectral analysis and cross-spectral analysis indicate that the records of diversity of calcareous nannoplankton (CN) and planktonic foraminifera (PF) and all of the geologic time series tested show similar dominant 25-33 Myr cycles. Based on the statistical results, best-fit stationary-periodic models for PF and CN evolutionary records can be constructed (with t=time in Myr): CN diversity = 9.5 sin(2pi(t - 7.5 Myr)/29 Myr) + 4.8 sin(2pi(t - 4 Myr)/15.3 Myr), and PF diversity = 7.6 sin(2pi(t - 12 Myr)/26 Myr) + 3 sin(2pit/9.2 Myr). These periodic models describe major patterns in the diversity history, such as: (1) a sawtooth-shaped 29-Myr cycle for calcareous nannoplankton diversity, with gradual increases and abrupt decreases in diversity; (2) plateau-shaped similar to 26-Myr cycles in the planktonic foraminifieral record, with abrupt diversity increases and decreases; and (3) the presence of similar to 15.3- and 9.2-Myr periodic components that modify the shapes of the 26- to 29-Myr cycles. Except for the synchronous decreases in diversity of PF and CN at 65 and similar to 34 Ma, the diversity extrema for the two planktonic groups have been on average similar to 2 to 3 Myr out of phase. In the similar to 30-Myr-cycle band, CN diversity increased with sea-level rise and increased paleotemperatures, whereas PF diversity was, in general, greater during times of lower sea levels. Diversity of PF and CN was reduced at times of major LIP eruptions and large impacts that follow - 15 or 30 Myr periodicities. These results suggest that the diversity of calcareous plankton since their appearance in the early Mesozoic has been modulated by long-term cyclical changes in global environmental conditions and by periodic large volcanic and impact events. The pacemaker, or pacemakers, for these cycles may be astrophysical, geophysical or some combination of the two. (C) 2004 Elsevier B.V. All rights reserved. C1 SPEEDSTAT, Ottawa, ON K1V 8T7, Canada. NYU, Earth & Environm Sci Program, New York, NY 10003 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Ottawa, Ottawa Carleton Geosci Ctr, Ottawa, ON K1N 6N5, Canada. Univ Ottawa, Dept Earth Sci, Ottawa, ON K1N 6N5, Canada. RP Prokoph, A (reprint author), SPEEDSTAT, 36 Corley Private, Ottawa, ON K1V 8T7, Canada. EM aprokocon@aol.com; mrr1@nyu.edu; helbilal@aix1.uottawa.ca NR 58 TC 9 Z9 9 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-0182 EI 1872-616X J9 PALAEOGEOGR PALAEOCL JI Paleogeogr. Paleoclimatol. Paleoecol. PD MAY 14 PY 2004 VL 207 IS 1-2 BP 105 EP 125 DI 10.1016/j.palaeo.2004.02.004 PG 21 WC Geography, Physical; Geosciences, Multidisciplinary; Paleontology SC Physical Geography; Geology; Paleontology GA 821TD UT WOS:000221484700006 ER PT J AU Liu, JP Curry, JA Hu, YY AF Liu, JP Curry, JA Hu, YY TI Recent Arctic Sea Ice Variability: Connections to the Arctic Oscillation and the ENSO SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NORTH-ATLANTIC OSCILLATION; TRENDS; EXTENTS; RECORD AB Trends in the satellite-derived Arctic sea ice concentrations (1978-2002) show pronounced decreases in the Barents/Kara Seas, between the Chukchi and Beaufort Seas, the central Sea of Okhotsk and a portion of the Hudson/Baffin Bay by similar to2-8% per decade, exceeding the 95% confidence level. Qualitatively speaking, positive phases of the Arctic Oscillation (AO) and El Nino-Southern Oscillation (ENSO) produce similar ice changes in the western Arctic, but opposite ice changes in the eastern Arctic. The manner in which the ice changes are related to the AO and ENSO are demonstrated. Over the last 24 years, the magnitude of the ice changes associated with the positive AO trend and the negative ENSO trend is much smaller than the regional ice trends. Thus, more local or less understood large scale processes should be investigated for explanations. C1 Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. EM jliu@eas.gatech.edu RI Hu, Yongyun /B-6786-2016; LIU, JIPING/N-6696-2016 OI Hu, Yongyun /0000-0002-4003-4630; NR 13 TC 45 Z9 49 U1 1 U2 17 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 13 PY 2004 VL 31 IS 9 AR L09211 DI 10.1029/2004GL019858 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 821PE UT WOS:000221473300005 ER PT J AU Lopez-Puertas, M Garcia-Comas, M Funke, B Picard, RH Winick, JR Wintersteiner, PP Mlynczak, MG Mertens, CJ Russell, JM Gordley, LL AF Lopez-Puertas, M Garcia-Comas, M Funke, B Picard, RH Winick, JR Wintersteiner, PP Mlynczak, MG Mertens, CJ Russell, JM Gordley, LL TI Evidence for an OH(upsilon) excitation mechanism of CO2 4.3 mu m nighttime emission from SABER/TIMED measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE mesosphere; CO2; 4.3 mu m emission; OH ID INFRARED ROCKET EXPERIMENT; ATMOSPHERIC LIMB EMISSION; MIDDLE ATMOSPHERE; UPPER MESOSPHERE; MODEL; TEMPERATURE; RELAXATION; AIRGLOW AB The SABER instrument on board the TIMED satellite, successfully launched on 7 December 2001, measures the CO2 4.3 mum atmospheric emission at day and night, from the troposphere up to the thermosphere, with a near global latitude coverage and with a very high signal-to-noise ratio. SABER has also three channels near 15 mum for the measurements of the pressure-temperature structure and two channels around 2.0 and 1.6 mum, mainly sensitive to the OH(upsilon less than or equal to 9) overtone radiation from levels upsilon = 8-9 and upsilon = 3-5, respectively. In this paper we analyze the measurements of SABER in channel 7, centered near 4.3 mum, taken at night in the upper mesosphere and lower thermosphere under quiet (nonauroral) conditions. The measurements of the 4.3 mum radiance in this region are much larger than expected under local thermodynamic equilibrium (LTE) and show a strong correlation with the OH channel signal. It was proposed by Kumer et al. [1978] that the CO2(upsilon(3)) levels, responsible for the emission at 4.3 mum, were excited from OH(upsilon) via vibrational-vibrational energy transfer with N-2(1) and hence to CO2(upsilon(3)). SABER data (measuring simultaneously pressure, temperature, CO2 4.3 mum emission, and OH(upsilon) near-IR emission) offer an unprecedented data set for understanding the non-LTE excitation mechanisms of CO2(upsilon(3)) in the nighttime mesosphere. We have investigated the SABER 4.3 mum radiances with the help of a non-LTE radiative transfer model for CO2 and found that the large radiances can be explained by a fast and efficient energy transfer rate from OH(upsilon) to N-2(1) to CO2(upsilon(3)), whereby, on average, 2.8-3 N-2(1) vibrational quanta are excited after quenching of one OH(upsilon) molecule. A series of alternative excitation mechanisms that may enhance the nighttime 4.3 mum limb radiance were considered and found to be insignificant. The mechanism(s) whereby the energy is transferred from OH(upsilon) to N-2(upsilon) is (are) still uncertain. The populations of OH(upsilon) are not significantly affected by incorporation of this fast transfer since N-2 quenching of OH(upsilon) is negligible when compared to O-2 quenching. C1 Inst Astrofis Andalucia, CSIC, E-18080 Granada, Spain. USAF, Res Lab, Space Vehicles Directorate, Bedford, MA 01731 USA. ARCON Corp, Waltham, MA 02154 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Hampton Univ, Ctr Atmosphere Sci, Hampton, VA 23668 USA. GATS Inc, Newport News, VA 23606 USA. RP Lopez-Puertas, M (reprint author), Inst Astrofis Andalucia, CSIC, Apartado Postal 3004, E-18080 Granada, Spain. EM puertas@iaa.es RI Mlynczak, Martin/K-3396-2012; Lopez Puertas, Manuel/M-8219-2013; Garcia-Comas, Maya/E-4050-2014; Funke, Bernd/C-2162-2008 OI Lopez Puertas, Manuel/0000-0003-2941-7734; Garcia-Comas, Maya/0000-0003-2323-4486; Funke, Bernd/0000-0003-0462-4702 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 MAY 13 PY 2004 VL 109 IS D9 AR D09307 DI 10.1029/2003JD004383 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 821PK UT WOS:000221474100001 ER PT J AU Khazanov, GV Liemohn, MW Fok, MC Newman, TS Ridley, AJ AF Khazanov, GV Liemohn, MW Fok, MC Newman, TS Ridley, AJ TI Stormtime particle energization with high temporal resolution AMIE potentials SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE ring current; radiation belts; magnetic storms; particle acceleration ID IONOSPHERIC ELECTRODYNAMICS TECHNIQUE; PITCH-ANGLE DIFFUSION; RING CURRENT IONS; RADIATION BELT; ELECTRIC-FIELD; MAGNETIC STORM; MAGNETOSPHERIC CONVECTION; SOLAR-WIND; EARTHS MAGNETOSPHERE; SALAMMBO CODE AB Simulations were conducted to investigate the influence of rapid electric field fluctuations on electron energization in the inner magnetosphere based on the assimilative mapping of ionospheric electrodynamics (AMIE) technique. Simulations for four different magnetic storms were run, namely those that occurred on 15 May 1997, 4 May 1998, 25 September 1998, and 19 October 1998. Here we have examined the formation of high-energy (100-500 keV) electrons in the inner magnetosphere during these storm events with our recently developed relativistic radiation belt transport code. The point of this numerical experiment is to show that a simulation of a real event must have the high time resolution electric field input files in order to produce the seed population for the radiation belts, which are often observed to increase in the days following a magnetic storm. Specifically, a cadence of the global electric field pattern of 5 min or less produces inner magnetospheric fluxes that are larger (by up to several orders of magnitude) than fluxes produced with a longer cadence. Differences were particularly large relative to simulation results with a 3-hour time cadence, analogous to a Kp-driven electric field model. C1 NASA, Natl Space Sci & Technol Ctr, George C Marshall Space Flight Ctr, Huntsville, AL 35899 USA. Univ Michigan, Space Phys Res Lab, Ann Arbor, MI 48109 USA. NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Alabama, Dept Comp Sci, Huntsville, AL 35899 USA. RP Khazanov, GV (reprint author), NASA, Natl Space Sci & Technol Ctr, George C Marshall Space Flight Ctr, Huntsville, AL 35899 USA. EM george.khazanov@msfc.nasa.gov; liemohn@umich.edu; mei-ching.fok@gsfc.nasa.gov; tnewman@cs.uah.edu; ridley@umich.edu RI Fok, Mei-Ching/D-1626-2012; Liemohn, Michael/H-8703-2012; Ridley, Aaron/F-3943-2011; feggans, john/F-5370-2012 OI Liemohn, Michael/0000-0002-7039-2631; Ridley, Aaron/0000-0001-6933-8534; NR 51 TC 16 Z9 16 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 MAY 13 PY 2004 VL 109 IS A5 AR A05209 DI 10.1029/2003JA010186 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 821PW UT WOS:000221475500002 ER PT J AU Singh, N Khazanov, G AF Singh, N Khazanov, G TI Numerical simulation of waves driven by plasma currents generated by low-frequency Alfven waves in a multi-ion plasma SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE Alfven waves; ion heating; wave-particle interactions; lower hybrid waves ID ELECTROSTATIC ION-CYCLOTRON; LOWER-HYBRID WAVES; INSTABILITY DRIVEN; FIELD; BEAM; ACCELERATION; MODE AB When multi-ion plasma consisting of heavy and light ions is permeated by a low-frequency Alfven (LFA) wave, the crossed-electric-and-magnetic field (E x B), and the polarization drifts of the different ion species and the electrons could be quite different. The relative drifts between the charged-particle species drive waves, which energize the plasma. Using 2.5-dimensional (2.5-D) particle-in-cell simulations, we study this process of wave generation and its nonlinear consequences in terms of acceleration and heating plasma. Specifically, we study the situation for LFA wave frequency being lower than the heavy-ion cyclotron frequency in a multi-ion plasma. We impose such a wave to the plasma assuming that its wavelength is much larger than that of the waves generated by the relative drifts. For better understanding, the LFA-wave driven simulations are augmented by those driven by initialized ion beams. The driven high-frequency (HF) wave modes critically depend on the heavy ion density n(h); for small values of n(h), the lower hybrid (LH) waves dominate. On the other hand, for large n(h) a significantly enhanced level of waves occurs over a much broader frequency spectrum below the LH frequency and such waves are interpreted here as the ion Bernstein (IB) mode near the light ion cyclotron harmonics. Irrespective of the driven wave modes, both the light and heavy ions undergo significant transverse acceleration, but for the large heavy-ion densities, even the electrons are significantly accelerated in the parallel direction by the waves below the LH frequency. Even when the LFA wave drive is maintained, the ion heating leads to the cessation of HF wave excitation just after a few cycles of the former wave. On the basis of marginal stability seen in the simulations, an empirical relation for LFA wave amplitude, frequency and ion temperature is given. C1 Univ Alabama, Dept Elect & Comp Engn, Huntsville, AL 35899 USA. NASA, Natl Space Sci & Technol Ctr, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Singh, N (reprint author), Univ Alabama, Dept Elect & Comp Engn, Huntsville, AL 35899 USA. EM singh@ece.uah.edu; george.khazanov@msfc.nasa.gov NR 24 TC 14 Z9 14 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 MAY 13 PY 2004 VL 109 IS A5 AR A05210 DI 10.1029/2003JA010251 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 821PW UT WOS:000221475500003 ER PT J AU Yuan, JC Miller, RL Powell, RT Dagg, MJ AF Yuan, JC Miller, RL Powell, RT Dagg, MJ TI Storm-induced injection of the Mississippi River plume into the open Gulf of Mexico SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID VARIABILITY; EDDIES; SEA; EVOLUTION; DELTA; SHELF AB The direct impact of the Mississippi River on the open Gulf of Mexico is typically considered to be limited due to the predominantly along-shore current pattern. Using satellite imagery, we analyzed chl a distributions in the northern Gulf of Mexico before and after the passage of two storms: Hurricane Lili and Tropical Storm Barry. Our analyses indicate that storm-induced eddies can rapidly inject large volumes of nutrient-rich Mississippi River water to the open gulf, and lead to phytoplankton blooms. Although these events last only a few weeks, they transport significant amounts of fluvial substances to the ocean. These river-ocean interactions are especially significant in tropical and subtropical regions because receiving waters are typically permanently stratified and oligotrophic. C1 Univ So Mississippi, Dept Marine Sci, Stennis Space Ctr, MS 39529 USA. NASA, Earth Sci Applicat Directorate, Stennis Space Ctr, MS 39529 USA. Louisiana Univ Marine Consortium, Chauvin, LA 70344 USA. RP Yuan, JC (reprint author), Univ So Mississippi, Dept Marine Sci, Stennis Space Ctr, MS 39529 USA. EM jinchun.yuan@usm.edu OI Powell, Rodney/0000-0001-5729-5557 NR 27 TC 24 Z9 24 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 12 PY 2004 VL 31 IS 9 AR L09312 DI 10.1029/2003GL019335 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 821PC UT WOS:000221473100001 ER PT J AU Prettyman, TH Feldman, WC Mellon, MT McKinney, GW Boynton, WV Karunatillake, S Lawrence, DJ Maurice, S Metzger, AE Murphy, JR Squyres, SW Starr, RD Tokar, RL AF Prettyman, TH Feldman, WC Mellon, MT McKinney, GW Boynton, WV Karunatillake, S Lawrence, DJ Maurice, S Metzger, AE Murphy, JR Squyres, SW Starr, RD Tokar, RL TI Composition and structure of the Martian surface at high southern latitudes from neutron spectroscopy SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars; polar processes; surface composition ID GENERAL-CIRCULATION MODEL; POLAR LAYERED DEPOSITS; X-RAY SPECTROMETER; MARS ODYSSEY; CARBON-DIOXIDE; GROUND ICE; PATHFINDER SITE; LANDING SITES; WATER-VAPOR; CO2 FROST AB Neutron spectroscopy data acquired by Mars Odyssey are analyzed to determine the abundance and depth of near-surface water ice as a function of latitude in the southern hemisphere as well as the inventory of CO2 in the south polar residual cap. The surface is modeled as a semi-infinite, water-rich permafrost layer covered by desiccated material, which is consistent with theoretical models of ground ice stability. Latitude-dependent parameters, water abundance and depth, are determined from zonally averaged neutron counting data. Spatial mixing of the output of neutrons from regions within the footprint of the spectrometer is modeled, and asymmetrical features such as the residual cap are included in the analysis. Absorption of thermal neutrons by major elements other than hydrogen is found to have a significant influence on the determination of water abundance. Poleward of -60degrees, the water-rich layer contains 60% +/- 10% water by weight (70% to 85% by volume) and is covered by less than 15 g/cm(2) +/- 5 g/cm(2) of dry material. The volume fraction of water is generally higher than can be accommodated in the pore space of surface soils, which implies that water vapor diffusion processes alone cannot explain the observations. Alternatives for the formation of the water-rich layer are discussed. Results of our analysis of the residual-cap CO2 inventory support conclusions that the atmosphere is not buffered by a larger reservoir of surface CO2 at the poles and that Mars' total CO2 inventory is well represented by the present atmospheric mass. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Observ Midi Pyrenees, Ctr Etud Spatiale Rayonnements, F-31400 Toulouse, France. CALTECH, Jet Prop Lab, Pasadena, CA USA. New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20017 USA. RP Los Alamos Natl Lab, Mail Stop D466, Los Alamos, NM 87545 USA. EM thp@lanl.gov; wfeldman@lanl.gov; mellon@argyre.colorado.edu; gwm@lanl.gov; wboynton@lpl.arizona.edu; wk43@cornell.edu; djlawrence@lanl.gov; sylvestre.maurice@cesr.fr; aem@eros.jpl.nasa.gov; murphy@nmsu.edu; squyres@astrosun.tn.cornell.edu; rstarr@lepvax.gsfc.nasa.gov; rlt@lanl.gov RI Karunatillake, Suniti/A-5934-2009; Mellon, Michael/C-3456-2016; Lawrence, David/E-7463-2015; OI Karunatillake, Suniti/0000-0001-9891-1432; Lawrence, David/0000-0002-7696-6667; Prettyman, Thomas/0000-0003-0072-2831 NR 75 TC 69 Z9 69 U1 1 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 12 PY 2004 VL 109 IS E5 AR E05001 DI 10.1029/2003JE002139 PG 28 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 821PQ UT WOS:000221474700001 ER PT J AU Jiang, L Chang, CL Choudhari, M Liu, CQ AF Jiang, L Chang, CL Choudhari, M Liu, CQ TI Instability-wave propagation in boundary-layer flows at subsonic through hypersonic Mach numbers SO MATHEMATICS AND COMPUTERS IN SIMULATION LA English DT Article; Proceedings Paper CT Workshop on Wave Phenomena in Physics and Engineering CY MAY, 2003 CL Montreal, CANADA DE direct numerical simulation; parabolized stability equations; laminar-turbulent transition; boundary layer ID DIRECT NUMERICAL-SIMULATION; EFFICIENT IMPLEMENTATION; FLAT-PLATE; TRANSITION; STABILITY; SCHEMES; VORTICES; CONE AB Direct numerical simulations (DNS) form an important ingredient to physics-based prediction of laminar-turbulent transition in boundary-layer flows, particularly in applications where it is desirable or even essential to model the various stages of transition process in an integrated manner. This paper addresses two building-block issues towards such capability: application to instability-wave propagation in boundary layers over curvilinear surfaces and robust outflow boundary conditions across the speed regime. In particular, detailed comparisons of linear and nonlinear development of instability waves in a range of boundary-layer flows are used to cross-validate a high-order direct numerical simulation algorithm against the approximate but computationally more. efficient technique of parabolized stability equations (PSE). Three separate flow configurations are investigated in this study: (i) development of a Tollmien-Schlichting (TS) instability wave over a two-dimensional (2D), symmetric, low-speed airfoil, (ii) both first and second-mode development in a self-similar, flat plate boundary layer at Mach 4.5, and (iii) amplification of first and second modes of Rayleigh instability and a stationary Gortler vortex in the hypersonic, axisymmetric boundary layer over a flared cone. The satisfactory agreement between the DNS and PSE predictions for both amplitudes and mode shapes of the instability waves confirms the overall efficacy of the DNS algorithm, while underscoring the accuracy of predictions based on the PSE approximation. Published by Elsevier B.V. on behalf of IMACS. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Texas, Arlington, TX 76019 USA. RP Choudhari, M (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM meelan.m.choudhari@nasa.gov RI Choudhari, Meelan/F-6080-2017 OI Choudhari, Meelan/0000-0001-9120-7362 NR 33 TC 3 Z9 3 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4754 J9 MATH COMPUT SIMULAT JI Math. Comput. Simul. PD MAY 11 PY 2004 VL 65 IS 4-5 BP 469 EP 487 DI 10.1016/j,matcom.2004.01.011 PG 19 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA 823GP UT WOS:000221598400012 ER PT J AU Cooray, A Bock, JJ Keatin, B Lange, AE Matsumoto, T AF Cooray, A Bock, JJ Keatin, B Lange, AE Matsumoto, T TI First star signature in infrared background anisotropies SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; diffuse radiation; galaxies : formation; infrared : galaxies; large-scale structure of universe ID COLD DARK-MATTER; PROBE WMAP OBSERVATIONS; DEEP GALAXY COUNTS; COBE DIRBE MAPS; ALL-SKY SURVEY; EVOLVING SPECTRA; POPULATION-III; ASTRO-F; FLUCTUATIONS; FIELD AB Recent cosmic microwave background anisotropy results from the Wilkinson Microwave Anisotropy Probe suggest that the universe was reionized at a redshift around 20 with an optical depth for Thomson scattering of 0.17 +/- 0.04. Such an early reionization could arise through the ionizing radiation emitted by metal-free Population III stars at redshifts of 10 and higher. We discuss infrared background (IRB) surface brightness spatial fluctuations from such a generation of early star formation. We show that the spatial clustering of these stars at tens of arcminute scales generates a contribution to the angular power spectrum of the IRB anisotropies at the same angular scales. This excess can be potentially detected when resolved foreground galaxies out to a redshift of a few are removed from the clustering analysis. We do not expect faint galaxies at redshifts of similar to3, with magnitudes less than 20 in the K band, to be a source of strong confusion, since the fractional contribution to the IRB from these galaxies is at a level less than a few percent, while the expected contribution from first stars can be 50% or more. Additionally, assuming a Population III stellar spectrum, we suggest that the clustering excess related to the first generation of stars can be separated from brightness fluctuations resulting from other foreground sources and galaxies using multifrequency observations in the wavelength range of similar to1-5 mum. In addition to identifying the IR clustering associated with low-redshift galaxy population, the multifrequency data are essential to account for certain foreground contaminants such as zodiacal light, which, if varying spatially over degree scales, can be a significant source of confusion for the proposed study. Using various instruments, we study the extent to which spatial fluctuations of the IRB can be studied in the near future. C1 CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Dept Infrared Astrophys, Kanagawa 2298510, Japan. RP Cooray, A (reprint author), CALTECH, Div Phys Math & Astron, MS 130-33,770 S Wilson Ave, Pasadena, CA 91125 USA. NR 58 TC 73 Z9 73 U1 1 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 MAY 10 PY 2004 VL 606 IS 2 BP 611 EP 624 DI 10.1086/383137 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 818RJ UT WOS:000221261900001 ER PT J AU Jenet, FA Lommen, A Larson, SL Wen, LQ AF Jenet, FA Lommen, A Larson, SL Wen, LQ TI Constraining the properties of supermassive black hole systems using pulsar timing: Application to 3C 66B SO ASTROPHYSICAL JOURNAL LA English DT Article DE black hole physics; gravitational waves; pulsars : general; pulsars : individual (B1855+09) ID ACTIVE GALACTIC NUCLEI; GRAVITATIONAL-RADIATION; BINARY; GALAXIES; MOTION; MASSES; WAVES AB General expressions for the expected timing residuals induced by gravitational wave (G-wave) emission from a slowly evolving, eccentric, binary black hole system are derived here for the first time. These expressions are used to search for the signature of G-waves emitted by the proposed supermassive binary black hole system in 3C 66B. We use data from long-term timing observations of the radio pulsar PSR B1855+09. For the case of a circular orbit, the emitted G-waves should generate clearly detectable fluctuations in the pulse-arrival times of PSR B1855+09. Since no G-waves are detected, the waveforms are used in a Monte Carlo analysis in order to place limits on the mass and eccentricity of the proposed black hole system. The analysis presented here rules out the adopted system with 95% confidence. The reported analysis also demonstrates several interesting features of a G-wave detector based on pulsar timing. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Franklin & Marshall Coll, Dept Phys & Astron, Lancaster, PA 17604 USA. CALTECH, LIGO Lab, Pasadena, CA 91125 USA. RP Jenet, FA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Larson, Shane/E-8576-2010 NR 21 TC 97 Z9 97 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2004 VL 606 IS 2 BP 799 EP 803 DI 10.1086/383020 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 818RJ UT WOS:000221261900013 ER PT J AU Strickland, DK Heckman, TM Colbert, EJM Hoopes, CG Weaver, KA AF Strickland, DK Heckman, TM Colbert, EJM Hoopes, CG Weaver, KA TI A high spatial resolution X-ray and H alpha study of hot gas in the halos of star-forming disk galaxies. II. Quantifying supernova feedback SO ASTROPHYSICAL JOURNAL LA English DT Review DE galaxies : halos; galaxies : individual (NGC 253, NGC 891, NGC 1482, NGC 3034, NGC 3073, NGC 3079, NGC 3628, NGC 4244, NGC 4631, NGC 4945, NGC 6503); galaxies : starburst; ISM : bubbles; ISM : jets and outflows; X-rays : galaxies ID DIFFUSE IONIZED-GAS; ON SPIRAL GALAXIES; HUBBLE-SPACE-TELESCOPE; MULTIVARIATE STATISTICAL-ANALYSIS; NEUTRAL HYDROGEN OBSERVATIONS; EXTRAGALACTIC DISTANCE SCALE; DRIVEN GALACTIC SUPERWINDS; ROSAT PSPC OBSERVATIONS; LARGE-MAGELLANIC-CLOUD; COLD DARK-MATTER AB We investigate how the empirical properties of hot X-ray-emitting gas in a sample of seven starburst and three normal edge-on spiral galaxies (a sample that covers the full range of star formation intensity found in disk galaxies) correlate with the size, mass, star formation rate, and star formation intensity in the host galaxies. From this analysis we investigate various aspects of mechanical energy "feedback''-the return of energy to the interstellar medium from massive star supernovae and stellar winds-on galactic scales. The X-ray observations make use of the unprecedented spatial resolution of the Chandra X-Ray Observatory to remove X-ray emission from point sources more accurately than in any previous study and hence obtain the X-ray properties of the diffuse thermal emission alone. Intriguingly, the diffuse X-ray properties of the normal spirals (in both their disks and halos) fall where extrapolation of the trends from the starburst galaxies with superwinds would predict. We demonstrate, using a variety of multiwavelength star formation rate and intensity indicators, that the luminosity of diffuse X-ray emission in the disk (and, where detected, in the halo) is directly proportional to the rate of mechanical energy feedback from massive stars in the host galaxies. Accretion of gas from the intergalactic medium (IGM) does not appear to be a significant contributor to the diffuse X-ray emission in this sample. Nevertheless, with only three nonstarburst normal spiral galaxies it is hard to exclude an accretion-based origin for extraplanar diffuse X-ray emission around normal star-forming galaxies. Larger galaxies tend to have more extended X-ray-emitting halos, but galaxy mass appears to play no role in determining the properties of the disk or extraplanar X-ray-emitting plasma. The combination of these luminosity and size correlations leads to a correlation between the surface brightness of the diffuse X-ray emission and the mean star formation rate per unit area in the disk (calculated from the far-infrared luminosity and the optical size of the galaxy, L-FIR=D-25(2)). Further observational work of this form will allow empirical constraints to be made on the critical star formation rate per unit disk area necessary to blow hot gas out of the disk into the halo. We show that a minor generalization of standard superbubble theory directly predicts a critical star formation rate per unit area for superbubble blowout from the disk and by extension for superwinds to blow out of the gaseous halos of their host galaxy. At present there are a variety of poorly known parameters in this theory that complicate comparison between observation and theory, making it impossible to assess the quantitative accuracy of standard superbubble blowout theory. We argue that the crucial spatial region around a galaxy that controls whether gas in starburst-driven superwinds will escape into the IGM is not the outer halo similar to100 kpc from the host galaxy, but the inner few halo scale heights, within similar to20 kpc of the galaxy plane. Given the properties of the gaseous halos we observe, superwind outflows from disk galaxies of mass Msimilar to10(10)-10(11) M-circle dot should still eject some fraction of their material into the IGM. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. NR 164 TC 162 Z9 162 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2004 VL 606 IS 2 BP 829 EP 852 DI 10.1086/383136 PN 1 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 818RJ UT WOS:000221261900017 ER PT J AU Remijan, A Sutton, EC Snyder, LE Friedel, DN Liu, SY Pei, CC AF Remijan, A Sutton, EC Snyder, LE Friedel, DN Liu, SY Pei, CC TI High-resolution observations of methyl cyanide (CH3CN) toward the hot core regions W51e1/e2 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : abundances; ISM : individual (W51); ISM : molecules; radio lines : ISM; stars : formation ID SPECTRAL-LINE SURVEY; MOLECULAR CORES; ORION-KL; W51; MILLIMETER; EXCITATION; EMISSION; GHZ; SAGITTARIUS-B2; ACID AB We have detected strong methyl cyanide (CH3CN) emission lines from the hot core regions W51e1 and W51e2, using the BIMA Array. This is the first survey of CH3CN toward W51 to utilize both 3 mm (J=5-4 and 6-5) and 1 mm (J=12-11, 13-12, and 14-13) transitions as probes of the physical and chemical conditions present in these regions. The emission reveals molecular clumps centered on the ultracompact H II regions found by Zhang and colleagues. The CH3CN lines show large optical depths in the lower K transitions toward both regions in W51. To determine the true kinetic temperatures, densities, and column densities of the emitting regions W51e1 and e2, statistical equilibrium models were used to calculate the relative populations of each energy level. The best fit to the observed spectra toward W51e1 is given by a temperature of 123(11) K, a hydrogen density of 5(1)x10(5) cm(-3), and a total methyl cyanide column density of 1.4(1)x10(16) cm(-2). The uncertainties describe a nominal 90% confidence interval for the last digit given. The best fit to the observed spectra toward W51e2 is given by a temperature of 153(21) K, a hydrogen density of 5(2)x10(5) cm(-3), and a total methyl cyanide column density of 3.8(7)x10(16) cm(-2). Our observations indicate that CH3CN can be used as a good probe of the physical conditions present in hot molecular cores and as a tracer of hard-to-detect large molecular species. Despite the differences in molecular structure and chemical formation mechanisms, methyl cyanide (CH3CN), ethyl cyanide (CH3CH2CN), and acetic acid (CH3COOH) are found to have similar abundances toward the W51e1 and e2 regions. In contrast, for a column density of CH3CN more than 15 times smaller than the column density of HCOOCH3 the integrated line flux is more than 7 times larger. Thus, because CH3CN lines are easy to detect, it appears to be a much better tracer of CH3CH2CN and CH3COOH than HCOOCH3. C1 Univ Illinois, Dept Astron, Urbana, IL 61801 USA. RP Remijan, A (reprint author), NASA, Goddard Space Flight Ctr, Earth & Space Data Comp Ctr, Code 930, Greenbelt, MD 20771 USA. EM aremijan@astro.uiuc.edu; sutton@astro.uiuc.edu; snyder@astro.uiuc.edu; friedel@astro.uiuc.edu; syliu@asiaa.sinica.edu.tw; ccpei@nj.col.com.cn RI Sutton, Edmund/H-5113-2011 NR 26 TC 44 Z9 44 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2004 VL 606 IS 2 BP 917 EP 928 DI 10.1086/383120 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 818RJ UT WOS:000221261900024 ER PT J AU Dyks, J Harding, AK Rudak, B AF Dyks, J Harding, AK Rudak, B TI Relativistic effects and polarization in three high-energy pulsar models SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : theory; polarization; pulsars : general; radiation mechanisms : nonthermal ID GAMMA-RAY PULSARS; OUTER GAP ACCELERATOR; RADIO-EMISSION GEOMETRY; BRIGHT EGRET PULSARS; POLAR-CAP MODELS; CRAB PULSAR; VELA PULSAR; SYNCHROTRON NEBULA; EMPIRICAL-THEORY; PAIR-PRODUCTION AB We present the influence of the special relativistic effects of aberration and light-travel time delay on pulsar high-energy light curves and polarization characteristics predicted by three models: the two-pole caustic model, the outer gap model, and the polar cap model. Position angle curves and degree of polarization are calculated for the models and compared with the optical data on the Crab pulsar. The relative positions of peaks in gamma-ray and radio light curves are discussed in detail for the models. We find that the two-pole caustic model can qualitatively reproduce the optical polarization characteristics of the Crab pulsar: fast swings of the position angle and minima in polarization degree, associated with both peaks. The anticorrelation between the observed flux and the polarization degree (observed in the optical band also for B0656+14) naturally results from the caustic nature of the peaks, which are produced in the model because of the superposition of radiation from many different altitudes, i.e., polarized at different angles. The two-pole caustic model also provides an acceptable interpretation of the main features in the Crab's radio profile. Neither the outer gap model nor the polar cap model is able to reproduce the optical polarization data on the Crab. Although the outer gap model is very successful in reproducing the relative positions of gamma-ray and radio peaks in pulse profiles, it can reproduce the high-energy light curves only when photon emission from regions very close to the light cylinder is included. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Nicholas Copernicus Astron Ctr, PL-87100 Torun, Poland. RP Dyks, J (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. EM jinx@milkyway.gsfc.nasa.gov; harding@twinkie.gsfc.nasa.gov; bronek@ncac.torun.pl RI Harding, Alice/D-3160-2012 NR 79 TC 125 Z9 125 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2004 VL 606 IS 2 BP 1125 EP 1142 DI 10.1086/383121 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 818RJ UT WOS:000221261900042 ER PT J AU Muslimov, AG Harding, AK AF Muslimov, AG Harding, AK TI High-altitude particle acceleration and radiation in pulsar slot gaps SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; gamma rays : theory; pulsars : general; radiation mechanisms : nonthermal; stars : neutron ID GAMMA-RAY PULSARS; OUTER MAGNETOSPHERE; PAIR FRONTS; POLAR CAPS; EMISSION; ELECTRODYNAMICS; CASCADES; MODEL AB We explore the pulsar slot gap (SG) electrodynamics up to very high altitudes, where for most relatively rapidly rotating pulsars both the standard small-angle approximation and the assumption that the magnetic field lines are ideal streamlines break down. We address the importance of the electrodynamic conditions at the SG boundaries and the occurrence of a steady state drift of charged particles across the SG field lines at very high altitudes. These boundary conditions and the deviation of particle trajectories from streamlines determine the asymptotic behavior of the scalar potential at all radii from the polar cap ( PC) to near the light cylinder. As a result, we demonstrate that the steady state accelerating electric field, E-parallel to, must approach a small and constant value at high altitude above the PC. This E-parallel to is capable of maintaining electrons moving with high Lorentz factors (similar tofew x 10(7)) and emitting curvature gamma-ray photons up to nearly the light cylinder. By numerical simulations, we show that primary electrons accelerating from the PC surface to high altitude in the SG along the outer edge of the open field region will form caustic emission patterns on the trailing dipole field lines. Acceleration and emission in such an extended SG may form the physical basis of a model that can successfully reproduce some pulsar high-energy light curves. C1 ManTech Int Corp, Lexington Pk, MD 20653 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Muslimov, AG (reprint author), ManTech Int Corp, Lexington Pk, MD 20653 USA. RI Harding, Alice/D-3160-2012 NR 32 TC 155 Z9 156 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2004 VL 606 IS 2 BP 1143 EP 1153 DI 10.1086/383079 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 818RJ UT WOS:000221261900043 ER PT J AU Bohm-Vitense, E Robinson, RD Carpenter, KG AF Bohm-Vitense, E Robinson, RD Carpenter, KG TI The O VI and C III lines at 1032 and 977 angstrom in Hyades F stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE open clusters and associations : individual (Hyades); stars : coronae; ultraviolet : stars ID YOUNG GALACTIC CLUSTERS; SOLAR-TYPE DWARFS; SPECTROGRAPH OBSERVATIONS; MAGNETIC-STRUCTURE; COOL STARS; EMISSION; DYNAMO; SUN AB We continue our investigations into the mechanisms heating the outer layers of cool dwarf stars. In this study we specifically seek to determine whether in the layers with temperatures around 250,000-300,000 K, in which the O VI lines are emitted, the temperatures are determined by heat conduction from the coronae or by the same processes that heat the lower temperature regions. To study this we discuss here 22 spectra of Hyades F stars taken by the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite to study the O VI lines at 1032 Angstrom and the C III lines at 977 Angstrom and compare them with other lower transition layer lines, observed with HST and IUE, and with existing X-ray data. For our targets with B-V>0.4, the X-ray fluxes of single F stars increase, on average, slowly with increasing B-V, while the O VI line fluxes show the same steep decrease around B-V=0.43 as previously found for the lower temperature transition layer lines. For single stars the X-ray fluxes decrease with increasing v sin i, except for the stars with B-V between 0.418 and 0.455, while for the O VI lines, as for the other transition layer lines, fluxes increase with increasing v sin i, if v sin i is larger than 30 km s(-1). For smaller v sin i, line fluxes are independent of v sin i. The B-V and v sin i dependences of the O VI line fluxes are then very different from those of the X-ray fluxes. We thus conclude that for electron temperature T-e below 300,000 K, the transition layers for Hyades F stars are not mainly heated by heat conduction from their coronae. C1 Univ Washington, Dept Astron, Seattle, WA 98195 USA. Catholic Univ Amer, Inst Astrophys & Computat Sci, Washington, DC 20064 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Bohm-Vitense, E (reprint author), Univ Washington, Dept Astron, POB 351580, Seattle, WA 98195 USA. NR 20 TC 1 Z9 1 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2004 VL 606 IS 2 BP 1174 EP 1183 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 818RJ UT WOS:000221261900046 ER PT J AU Still, M Boyd, P AF Still, M Boyd, P TI Fine-tuning the accretion disk clock in Hercules X-1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; ephemerides; instabilities; X-rays : binaries; X-rays : individual (Hercules X-1) ID ANOMALOUS LOW-STATE; X-RAY BINARIES; 35 DAY CYCLE; X-1-HZ HERCULIS; MASS-TRANSFER; MAIN-ON; MULTIWAVELENGTH; BEPPOSAX; MODEL; UHURU AB Rossi X-Ray Timing Explorer all-sky monitor count rates from the X-ray pulsar Her X-1 began falling consistently during the late months of 2003. The source is undergoing another state transition similar to the anomalous low state of 1999. This new event has triggered observations from both space- and ground-based observatories. In order to aid data interpretation and telescope scheduling and to facilitate the phase connection of cycles before and after the state transition, we have recalculated the precession ephemeris using cycles over the last 3.5 yr. We report that the source has displayed a different precession period since the last anomalous event. Additional archival data from the Compton Gamma Ray Observatory suggests that each low state is accompanied by a change in precession period and that the subsequent period is correlated with accretion flux. Consequently our analysis reveals long-term accretion disk behavior that is predicted by theoretical models of radiation-driven warping. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Still, M (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. EM martin.still@gsfc.nasa.gov; padi@milkyway.gsfc.nasa.gov RI Boyd, Patricia/D-3274-2012 NR 34 TC 17 Z9 18 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2004 VL 606 IS 2 BP L135 EP L138 DI 10.1086/421349 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 818RL UT WOS:000221262100012 ER PT J AU Wolff, CL Mayr, HG AF Wolff, CL Mayr, HG TI The Sun's reversing flows and heat spike as caused by g-modes SO ASTROPHYSICAL JOURNAL LA English DT Article DE hydrodynamics; Sun : interior; Sun : oscillations; waves ID ANGULAR-MOMENTUM TRANSPORT; QUASI-BIENNIAL OSCILLATION; SOLAR CONVECTION ZONE; WAVE-DRIVEN FLOWS; GRAVITY-WAVES; INTERNAL WAVES; TACHOCLINE; INTERIOR; ROTATION; SHEAR AB The reversing east-west flows centered near 0.675 R-. have not been explained by gravity waves from the convection zone because suitable wavelengths do not penetrate deeply enough to drive the observed flow. An alternative is explored using g-modes, many of whose rotation rates have already been detected. Simple formulas for the radial drift of the flow and for angular momentum transfer from asymptotic g-modes are expressed in terms of local oscillation amplitudes and dissipation rates. The main loss mechanism is horizontal turbulence caused by the flow. It exceeds that due to gravity waves for which Schatzman estimated a diffusivity similar to 10(8) m(2) s(-1). Our proposed flow has a peak zonal speed of 50 m s(-1), consistent with the observations at current resolving power. An array of g-modes with amplitudes near the detectable limit at the solar surface can cause the flow to replace itself about every 1.3 yr, as observed, if there are similar to 10(3) high harmonic modes. Since the flow occupies the same thin layer where the sound speed is anomalous, heat dissipated in driving the flow acts to reduce that solar modeling error. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wolff, CL (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM charles.wolff@nasa.gov; hans.g.mayr@nasa.gov OI Wolff, Charles/0000-0001-8854-507X NR 28 TC 5 Z9 5 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2004 VL 606 IS 2 BP L163 EP L166 DI 10.1086/421327 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 818RL UT WOS:000221262100019 ER PT J AU Tapley, BD Bettadpur, S Watkins, M Reigber, C AF Tapley, BD Bettadpur, S Watkins, M Reigber, C TI The gravity recovery and climate experiment: Mission overview and early results SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB The GRACE mission is designed to track changes in the Earth's gravity field for a period of five years. Launched in March 2002, the two GRACE satellites have collected nearly two years of data. A span of data available during the Commissioning Phase was used to obtain initial gravity models. The gravity models developed with this data are more than an order of magnitude better at the long and mid wavelengths than previous models. The error estimates indicate a 2-cm accuracy uniformly over the land and ocean regions, a consequence of the highly accurate, global and homogenous nature of the GRACE data. These early results are a strong affirmation of the GRACE mission concept. C1 Univ Texas, Ctr Space Res, Austin, TX 78759 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Geoforsch Zentrum, Potsdam, Germany. RP Tapley, BD (reprint author), Univ Texas, Ctr Space Res, 3925 W Braker Lane,Suite 200, Austin, TX 78759 USA. EM tapley@csr.utexas.edu RI Bettadpur, Srinivas/M-3744-2014 NR 9 TC 867 Z9 905 U1 10 U2 79 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 8 PY 2004 VL 31 IS 9 AR L09607 DI 10.1029/2004GL019920 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 819RW UT WOS:000221333700005 ER PT J AU Vidal, N Hedges, SB AF Vidal, N Hedges, SB TI Molecular evidence for a terrestrial origin of snakes SO PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES LA English DT Article DE evolution; phylogeny; reptiles; squamates; lizards; mosasaurs ID HIGHER-LEVEL RELATIONSHIPS; PHYLOGENETIC ANALYSIS; MITOCHONDRIAL GENES; SOFT ANATOMY; FOSSIL SNAKE; MIDDLE-EAST; 4 NUCLEAR; LIZARDS; LEGS; MOSASAUROIDS AB Biologists have debated the origin of snakes since the nineteenth century. One hypothesis suggests that snakes are most closely related to terrestrial lizards, and reduced their limbs on land. An alternative hypothesis proposes that snakes are most closely related to Cretaceous marine lizards, such as mosasaurs, and reduced their limbs in water. A presumed close relationship between living monitor lizards, believed to be close relatives of the extinct mosasaurs, and snakes has bolstered the marine origin hypothesis. Here, we show that DNA sequence evidence does not support a close relationship between snakes and monitor lizards, and thus supports a terrestrial origin of snakes. C1 Penn State Univ, NASA, Astrobiol Inst, University Pk, PA 16802 USA. Penn State Univ, Dept Biol, Mueller Lab 208, University Pk, PA 16802 USA. RP Hedges, SB (reprint author), Penn State Univ, NASA, Astrobiol Inst, University Pk, PA 16802 USA. EM sbh1@psu.edu NR 44 TC 65 Z9 71 U1 4 U2 38 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 0962-8452 J9 P ROY SOC B-BIOL SCI JI Proc. R. Soc. B-Biol. Sci. PD MAY 7 PY 2004 VL 271 SU 4 BP S226 EP S229 DI 10.1098/rsbl.2003.0151 PG 4 WC Biology; Ecology; Evolutionary Biology SC Life Sciences & Biomedicine - Other Topics; Environmental Sciences & Ecology; Evolutionary Biology GA 819NG UT WOS:000221321100030 PM 15252991 ER PT J AU Wundrow, DW Khavaran, A AF Wundrow, DW Khavaran, A TI On the applicability of high-frequency approximations to Lilley's equation SO JOURNAL OF SOUND AND VIBRATION LA English DT Article ID INHOMOGENEOUS MEDIA; NOISE; DIFFRACTION; FLOWS; JET; LAYER AB Three forms of the high-frequency asymptotic Green function for Lilley's equation are reviewed and compared to the exact solution over a wide range of Strouhal numbers. The asymmetric approximation, which applies to sources away from the jet axis, and the quasi-symmetric approximation, which uses a near-axis source assumption, are both obtained for parallel round jets from a formal Fourier-transform solution. The latter of the two is the basis of the so-called MGB computer code (High velocity Jet noise source location and reduction, FAA-RD-76-96-II, 1978) and its derivatives. The ray-theory solution, which is the only high-frequency approximation that can be applied to more general mean flows, follows from a WKB ansatz and is shown to be closely related to the asymmetric approximation. The comparisons show that the best overall prediction of the exact Green function is given by the asymmetric approximation which remains accurate down to a Strouhal number of 1/2. The close relationship between the asymmetric and ray-theory approximations suggests that the high-frequency asymptotic Green function for more general mean flows would be similarly successful. (C) 2003 Elsevier Ltd. All rights reserved. C1 Ohio Aerosp Inst, Brookpark, OH 44142 USA. QSS Grp, Cleveland, OH 44135 USA. RP Wundrow, DW (reprint author), Glenn Res Ctr, Mailstop 5-9 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM david.w.wundrow@grc.nasa.gov NR 21 TC 11 Z9 11 U1 0 U2 0 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 MAY 6 PY 2004 VL 272 IS 3-5 BP 793 EP 830 DI 10.1016/S0022-460X(03)00420-6 PG 38 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 814UW UT WOS:000221000600016 ER PT J AU DiCarlo, JA Yun, HM Hurst, JB AF DiCarlo, JA Yun, HM Hurst, JB TI Fracture mechanisms for SiC fibers and SiC/SiC composites under stress-rupture conditions at high temperatures SO APPLIED MATHEMATICS AND COMPUTATION LA English DT Article DE SiC fibers; SiC matrices; SiC/SiC composites; creep; rupture; mechanisms; Monkman-Grant diagrams ID TENSILE CREEP-BEHAVIOR AB The successful application of SiC/SiC ceramic matrix composites as high-temperature structural materials depends strongly on maximizing the fracture or rupture life of the load-bearing fiber and matrix constituents. Using high-temperature data measured under stress-rupture test conditions, this study examines in a mechanistic manner the effects of various intrinsic and extrinsic factors on the creep and fracture behavior of a variety of SiC fiber types. It is shown that although some fiber types fracture during a large primary creep stage, the fiber creep rate just prior to fracture plays a key role in determining fiber rupture time (Monkman-Grant theory). If it is assumed that SiC matrices rupture in a similar manner as fibers with the same microstructures, one can develop simple mechanistic models to analyze and optimize the stress-rupture behavior of SiC/SiC composites for applied stresses that are initially below matrix cracking. Published by Elsevier Inc. C1 NASA, Glenn Res Ctr, Div Mat, Cleveland, OH 44135 USA. RP DiCarlo, JA (reprint author), NASA, Glenn Res Ctr, Div Mat, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM james.a.dicarlo@nasa.gov NR 24 TC 16 Z9 16 U1 1 U2 7 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0096-3003 J9 APPL MATH COMPUT JI Appl. Math. Comput. PD MAY 5 PY 2004 VL 152 IS 2 BP 473 EP 481 DI 10.1016/S0096-3003(03)00570-8 PG 9 WC Mathematics, Applied SC Mathematics GA 841RR UT WOS:000222949600012 ER PT J AU Brillson, LJ Tumakha, S Okojie, RS Zhang, M Pirouz, P AF Brillson, LJ Tumakha, S Okojie, RS Zhang, M Pirouz, P TI Electron-excited luminescence of SiC surfaces and interfaces SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Review ID SCHOTTKY-BARRIER HEIGHT; 3C-SIC POLYTYPIC TRANSFORMATION; SILICON-CARBIDE; STACKING-FAULTS; EMISSION MICROSCOPY; EPITAXIAL LAYERS; HIGH-TEMPERATURE; SINGLE-CRYSTALS; 6H-SIC SURFACES; SPIN-RESONANCE AB Recent advances in probing the electronic structure of SiC with electron-excited luminescence techniques reveal the presence of localized electronic states near its surfaces and interfaces. These localized states form not only as a result of interface chemical bonding but also due to the formation of new lattice polytypes. Such electronic features are sensitive to the conditions under which the SiC is processed, as well as the application of electrical or mechanical stress. These localized changes on a nanometre scale provide a new perspective to Schottky barrier formation, band alignment, and polytypism in SiC as well as its performance in electronic devices. C1 Ohio State Univ, Dreese Lab 205, Columbus, OH 43210 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Case Western Reserve Univ, Dept Mat Sci & Engn, Cleveland, OH 44106 USA. RP Brillson, LJ (reprint author), Ohio State Univ, Dreese Lab 205, 2015 Neil Ave, Columbus, OH 43210 USA. EM Brillson.1@osu.edu NR 90 TC 10 Z9 10 U1 0 U2 4 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 MAY 5 PY 2004 VL 16 IS 17 BP S1733 EP S1754 AR PII S0953-8984(04)65085-5 DI 10.1088/0953-8984/16/17/015 PG 22 WC Physics, Condensed Matter SC Physics GA 821SN UT WOS:000221483000016 ER PT J AU Smialek, JL AF Smialek, JL TI Universal characteristics of an interfacial spalling cyclic oxidation model SO ACTA MATERIALIA LA English DT Article DE thermal cycling; oxidation; modeling; kinetics; nickel alloys ID COSP AB A mathematical model has been generated to represent the iterative, discrete growth and spallation processes associated with cyclic oxidation. Parabolic growth kinetics (k(p)) and a constant spall area (F-A) were assumed, with spalling occurring interfacially at the thickest region of the scale. Although most models require numerical techniques, the regularity and simplicity of this progression permitted an approximation by algebraic expressions. Normalized responses reflected all parametric effects and yielded a universal cyclic oxidation expression: W-u = 1/2{3J(u)(1/2) + J(u)(3/2)}, where W-u is weight change normalized by the maximum and J(u) is the cycle number normalized by the number to reach maximum. similarly. the total amount of metal consumed was represented by a single normalized curve, using the figure of merit [(S-c - 1) (.) (F(A)k(p)Deltat)(1/2)], where S-c is the scale mass ratio of oxide to oxygen and Deltat is the cycle duration. Also, a universal or invariant cyclic oxidation failure map was constructed in normalized k(p)-F-A space. Published by Elsevier Ltd on behalf of Acta Materialia Inc. C1 NASA, Glenn Res Ctr, Dept Mat, Cleveland, OH 44135 USA. RP Smialek, JL (reprint author), NASA, Glenn Res Ctr, Dept Mat, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM janies.l.smialek@nasa.gov NR 16 TC 16 Z9 16 U1 2 U2 8 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 MAY 3 PY 2004 VL 52 IS 8 BP 2111 EP 2121 DI 10.1016/j.actamat.2004.01.032 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 820JS UT WOS:000221385600001 ER PT J AU Andre, CL Boeckl, JJ Wilt, DM Pitera, AJ Lee, ML Fitzgerald, EA Keyes, BM Ringel, SA AF Andre, CL Boeckl, JJ Wilt, DM Pitera, AJ Lee, ML Fitzgerald, EA Keyes, BM Ringel, SA TI Impact of dislocations on minority carrier electron and hole lifetimes in GaAs grown on metamorphic SiGe substrates SO APPLIED PHYSICS LETTERS LA English DT Article ID BUFFER LAYERS; SOLAR-CELLS; QUALITY GAAS; MOBILITY AB The minority carrier lifetime of electrons (tau(n)) in p-type GaAs double heterostructures grown on GaAs substrates and compositionally graded Ge/Si1-xGex/Si (SiGe) substrates with varying threading dislocation densities (TDDs) were measured at room temperature using time-resolved photoluminescence. The electron lifetimes for homoepitaxial GaAs and GaAs grown on SiGe (TDDsimilar to1x10(6) cm(-2)) with a dopant concentration of 2x10(17) cm(-3) were similar to21 and similar to1.5 ns, respectively. The electron lifetime measured on SiGe was substantially lower than the previously measured minority carrier hole lifetime (tau(p)) of similar to10 ns, for n-type GaAs grown on SiGe substrates with a similar residual TDD and dopant concentration. The reduced lifetime for electrons is a consequence of their higher mobility, which yields an increased sensitivity to the presence of dislocations in GaAs grown on metamorphic buffers. The disparity in dislocation sensitivity for electron and hole recombination has significant implications for metamorphic III-V devices. (C) 2004 American Institute of Physics. C1 Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. NASA, Glenn Res Ctr, Photovolta & Space Environm Branch, Cleveland, OH 44135 USA. MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Ringel, SA (reprint author), Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. EM ringel@ece.eng.osu.edu RI Lee, Minjoo/A-9720-2008 OI Lee, Minjoo/0000-0002-3151-3808 NR 22 TC 42 Z9 42 U1 0 U2 13 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 3 PY 2004 VL 84 IS 18 BP 3447 EP 3449 DI 10.1063/1.1736318 PG 3 WC Physics, Applied SC Physics GA 815SR UT WOS:000221062500005 ER PT J AU Yoshie, T Loncar, M Scherer, A Qiu, Y AF Yoshie, T Loncar, M Scherer, A Qiu, Y TI High frequency oscillation in photonic crystal nanolasers SO APPLIED PHYSICS LETTERS LA English DT Article ID ENHANCED SPONTANEOUS EMISSION; ROOM-TEMPERATURE; SEMICONDUCTOR-LASERS; MU-M; MICROCAVITY; DEFECT; OPERATION; MODE AB We observed modulated oscillations in lasers of up to 130 GHz by conducting frequency domain measurements on photonic crystal lasers with built-in saturable absorbers. This is an example of how the small volumes of photonic crystal lasers lead to increases in the internal modulation frequencies and enables dramatic improvements of the laser modulation rate. (C) 2004 American Institute of Physics. C1 CALTECH, Dept Elect Engn, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Dept Elect Engn, Pasadena, CA 91125 USA. EM yoshie@caltech.edu RI Yoshie, Tomoyuki/C-3567-2008 NR 26 TC 19 Z9 19 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 3 PY 2004 VL 84 IS 18 BP 3543 EP 3545 DI 10.1063/1.1713051 PG 3 WC Physics, Applied SC Physics GA 815SR UT WOS:000221062500037 ER PT J AU Yang, RQ Hill, CJ Yang, BH Wong, CM Muller, RE Echternach, PM AF Yang, RQ Hill, CJ Yang, BH Wong, CM Muller, RE Echternach, PM TI Continuous-wave operation of distributed feedback interband cascade lasers SO APPLIED PHYSICS LETTERS LA English DT Article ID ROOM-TEMPERATURE; MU-M AB Continuous-wave distributed feedback interband cascade lasers operating near 3.3 mum are reported. Single longitudinal mode emission is achieved with side mode suppression ratio greater than 30 dB at temperatures up to 175 K. A clear Bragg stop band in the laser emission spectrum indicates a dominant index coupling with the first-order grating. Detailed characteristics of these lasers are discussed. (C) 2004 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yang, RQ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM rui.q.yang@jpl.nasa.gov NR 12 TC 39 Z9 40 U1 3 U2 4 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 3 PY 2004 VL 84 IS 18 BP 3699 EP 3701 DI 10.1063/1.1738184 PG 3 WC Physics, Applied SC Physics GA 815SR UT WOS:000221062500089 ER PT J AU Lissenden, CJ Colaiuta, JF Lerch, BA AF Lissenden, CJ Colaiuta, JF Lerch, BA TI Hardening behavior of three metallic alloys under combined stresses at elevated temperature SO ACTA MECHANICA LA English DT Article ID YIELD SURFACE DISTORTION; ANISOTROPIC METALS; FLOW SURFACES; INCONEL 718; PLASTICITY; MODEL; FORMULATION; ALUMINUM; STRAIN AB Initial and subsequent yield loci for type 316 stainless steel, Haynes 188, and Inconel 718 are determined experimentally in the axial-shear stress plane at 650 C. Each of these materials has a face centered cubic (fcc) crystal structure, but entirely different chemical compositions and strengthening mechanisms. Material hardening behavior is described along three cyclic strain paths having a maximum equivalent strain of 0.015 m/m: fully reversed axial (Path 1), fully reversed shear (Path II), and a nonproportional hourglass shaped path (Path III). Yielding is defined by a Mises-type equivalent offset strain definition having a target value of 30 mum/m. These types of yield surface determination tests are difficult, but fairly common in lower temperature ranges where precision strain gages can be used. Due to the high temperature in this study, axial and shear strains were measured by an extensometer. These results, which describe material hardening by the evolution of size, shape, and position of the current yield surface can be used in support of constitutive models for high temperature metallic materials. Hardening behavior of all three alloys is well described by a mixed hardening rule comprised of isotropic, kinematic, and distortional components. Relative to published work at lower temperatures, the isotropic hardening component is larger and the distortional hardening component is smaller than anticipated. C1 Penn State Univ, Dept Engn Sci & Mech, University Pk, PA 16802 USA. NASA, Glenn Res Ctr, Life Predict Branch, Cleveland, OH 44135 USA. RP Lissenden, CJ (reprint author), Penn State Univ, Dept Engn Sci & Mech, 227 Hammond Bldg, University Pk, PA 16802 USA. EM lissenden@psu.edu NR 39 TC 8 Z9 8 U1 3 U2 10 PU SPRINGER WIEN PI VIENNA PA SACHSENPLATZ 4-6, PO BOX 89, A-1201 VIENNA, AUSTRIA SN 0001-5970 J9 ACTA MECH JI Acta Mech. PD MAY PY 2004 VL 169 IS 1-4 BP 53 EP 77 DI 10.1007/s00707-004-0092-3 PG 25 WC Mechanics SC Mechanics GA 828NV UT WOS:000221980900005 ER PT J AU Milanovic, IM Zaman, KBMQ AF Milanovic, IM Zaman, KBMQ TI Fluid dynamics of highly pitched and yawed jets in crossflow SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut ID TURBULENT-BOUNDARY-LAYER; VORTEX AB Results from an experimental investigation of flowfields generated by pitched and yawed jets discharging into a crossflow are presented. The circular jet is pitched at alpha = 20 and 45 deg and yawed between beta = 0 and 90 deg in increments of 15 deg. Hot-wire measurements are performed to obtain all three components of mean velocity and turbulent stresses. Cross-sectional surveys are conducted at x = 3, 5, 10, and 20, where the downstream distance x is normalized by the orifice diameter. Data are acquired at momentum-flux ratio, J = 1.5, 4, 8, and 20. As expected, the jet penetration is found to be higher at larger alpha. With increasing beta the jet spreads more. The rate of decrease of peak streamwise vorticity, partial derivativeomega(x max)/partial derivativex, is found to be significantly lower at higher beta but practically independent of a. Thus, at the farthest measurement station, x = 20, omega(x max) is about five times larger at beta = 75 deg compared to that at beta = 0 deg. Streamwise velocity within the jet-vortex structure is found to depend on the parameter J. At J = 1.5 and 4, wake-like velocity profiles are observed. In comparison, a jet-like overshoot is present at higher J. Distributions of turbulent stresses for various cases are documented. Regions of high normal stresses, dispersed initially, are eventually ingested by the streamwise vortices. Thus, at x = 10 and farther downstream the well-defined cores of the streamwise vortices are also the zones of highest turbulent activity. C1 NASA, John H Glenn Res Ctr Lewis Field, Nozzle Branch, Trubomachinery & Prop Syst Div, Cleveland, OH 44135 USA. Univ Hartford, Coll Engn Technol & Architecture, Hartford, CT 06117 USA. RP Milanovic, IM (reprint author), Univ Hartford, Coll Engn Technol & Architecture, 200 Bloomfield Ave, Hartford, CT 06117 USA. EM Milanovic@hartford.edu; Khairul.B.Zaman@nasa.gov OI Milanovic, Ivana/0000-0002-9985-6014 NR 21 TC 13 Z9 13 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 2004 VL 42 IS 5 BP 874 EP 882 DI 10.2514/1.2924 PG 9 WC Engineering, Aerospace SC Engineering GA 821LS UT WOS:000221462700002 ER PT J AU Maestrello, L AF Maestrello, L TI Synchronized turbulent boundary layer-flexible structure by sound and transient shock wave SO AIAA JOURNAL LA English DT Article ID COUPLED OSCILLATOR-SYSTEMS; PHASE SYNCHRONIZATION; CHAOTIC OSCILLATORS; GENERALIZED SYNCHRONIZATION; SLIPS; PANEL; FLOW AB Acoustic and turbulent boundary-layer flow loadings over a flexible structure are used to study the spatial-temporal dynamics of the response of the structure. The stability of the spatial phase synchronization and desynchronization by an active external force is investigated from time series with an array of coupled transducers on the structure. In the synchronous state, the structural phase is locked, which leads to the formation of spatial patterns while the amplitude peaks exhibit chaotic behaviors. Large-amplitude, spatially symmetric loading is superimposed on broadband, but in the desynchronized state, the spectrum broadens and the phase space is lost. The resulting pattern bears a striking resemblance to phase turbulence. The transition is achieved by using a low-power external actuator to trigger broadband behaviors from the knowledge of the external acoustic load, inducing synchronization. The changes are made favorably and efficiently to alter the frequency distribution of power, not the total power level. Before synchronization effects are seen, the panel response to the turbulent boundary-layer loading is discontinuously spatiotemporally correlated. The stability develops from different competing wavelengths; the spatial scale is significantly shorter than when forced with the superimposed external sound. When the external sound level decreases and the synchronized phases are lost, changes in the character of the spectra can be linked to the occurrence of spatial phase transition. These changes can develop broadband response. Synchronized wall pressure loading on a fuselage structural panel induced by turbulent boundary layer and by traveling transient shock wave has been observed in flight. Results from two flight tests are discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Maestrello, L (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 36 TC 0 Z9 0 U1 2 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 2004 VL 42 IS 5 BP 920 EP 930 DI 10.2514/1.9587 PG 11 WC Engineering, Aerospace SC Engineering GA 821LS UT WOS:000221462700008 ER PT J AU Rule, JA Cox, DE Clark, RL AF Rule, JA Cox, DE Clark, RL TI Aerodynamic model reduction through balanced realization SO AIAA JOURNAL LA English DT Article ID UNSTEADY FLOWS C1 Duke Univ, Dept Mech Engn & Mat Sci, Durham, NC 27708 USA. NASA, Langley Res Ctr, Guidance & Control Branch, Hampton, VA 23681 USA. RP Rule, JA (reprint author), Alphatech Inc, 6 New England Execut Pk, Burlington, MA 01803 USA. NR 14 TC 1 Z9 1 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 2004 VL 42 IS 5 BP 1045 EP 1048 DI 10.2514/1.9596 PG 4 WC Engineering, Aerospace SC Engineering GA 821LS UT WOS:000221462700022 ER PT J AU Golden, DC Ming, DW Morris, RV Brearley, A Lauer, HV Treiman, AH Zolensky, ME Schwandt, CS Lofgren, GE McKay, GA AF Golden, DC Ming, DW Morris, RV Brearley, A Lauer, HV Treiman, AH Zolensky, ME Schwandt, CS Lofgren, GE McKay, GA TI Evidence for exclusively inorganic formation of magnetite in Martian meteorite ALH84001 SO AMERICAN MINERALOGIST LA English DT Article ID ALLAN HILLS 84001; MAGNETOTACTIC BACTERIA; CARBONATE GLOBULES; MARS; MAGNETOFOSSILS; MORPHOLOGY; CRYSTALS; HISTORY; ORIGIN; GROWTH AB Magnetite crystals produced by terrestrial magnetotactic bacterium MV-1 are elongated on a [111] crystallographic axis, in a so-called "truncated hexa-octahedral" shape. This morphology has been proposed to constitute a biomarker (i.e.. formed only in biogenic processes). A subpopulation of magnetite crystals associated with carbonate globules in Martian meteorite ALH84001 is reported to have this morphology, and the observation has been taken as evidence for biological activity on Mars. In this study, we present evidence for the exclusively inorganic origin of [111]-elongated magnetite crystals in ALH84001. We report three-dimensional (3-D) morphologies for similar to1000 magnetite crystals extracted from: (1) thermal decomposition products of Fe-rich carbonate produced by inorganic hydrothermal precipitation in laboratory experiments; (2) carbonate globules in Martian meteorite ALH84001: and (3) cells of magnetotactic bacterial strain MV-1. The 3-D morphologies were derived by fitting 3-D shape models to two-dimensional bright-field transmission-electron microscope (TEM) images obtained at a series of viewing angles. The view down the {110} axes closest to the [111] elongation axis of magnetite crystals ([111](.){110} not equal 0) provides a 2-D projection that uniquely discriminates among the three [111]-elongated magnetite morphologies found in these samples: [111]-elongated truncated hexaoctahedron ([111]-THO), [111]-elongated cubo-octahedron ([111]-ECO), and [111]-elongated simple octahedron ([111]-ESO). All [111]-elongated morphologies are present in the three types of sample,but in different proportions. In the ALH84001 Martian meteorite and in our inorganic laboratory products, the most common [111]-elongated magnetite crystal morphology is [111]-ECO. In contrast, the most common morphology for magnetotactic bacterial strain MV-1 is [111]-THO. These results show that: (1) the morphology of [111]-elongated magnetite crystals associated with the carbonate globules in Martian meteorite ALH84001 is replicated by an inorganic process; and (2) the most common crystal morphology for biogenic (MV-1) magnetite is distinctly different from that in both ALH84001 and our inorganic laboratory products. Therefore, [111]-elongated magnetite crystals in ALH84001 do not constitute, as previously claimed, a "robust biosignature" and, in fact, an exclusively inorganic origin for the magnetite is fully consistent with our results. Furthermore, the inorganic synthesis method, i.e., the thermal decomposition of hydrothermally precipitated Fe-rich carbonate, is a process analogue for formation of the magnetite on Mars. Namely, precipitation of carbonate globules from carbonate-rich hydrothermal solutions followed at some later time by a thermal pulse, perhaps in association with meteoritic impact or volcanic processes on the Martian surface. C1 Hernandez Engn Inc, Houston, TX 77062 USA. NASA, Lyndon B Johnson Space Ctr, Astromat Res & Explorat Sci Off, Houston, TX 77058 USA. Univ New Mexico, Dept Earth & Planetary Sci, Albuquerque, NM USA. Lockheed Martin, Houston, TX 77258 USA. Lunar & Planetary Inst, Houston, TX 77058 USA. RP Ming, DW (reprint author), Hernandez Engn Inc, 16055 Space Ctr Blvd,Suite 725, Houston, TX 77062 USA. EM douglas.w.ming@nasa.gov NR 34 TC 54 Z9 57 U1 3 U2 16 PU MINERALOGICAL SOC AMER PI WASHINGTON PA 1015 EIGHTEENTH ST, NW SUITE 601, WASHINGTON, DC 20036 USA SN 0003-004X J9 AM MINERAL JI Am. Miner. PD MAY-JUN PY 2004 VL 89 IS 5-6 BP 681 EP 695 PG 15 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 824IM UT WOS:000221680000002 ER PT J AU Herd, CDK Treiman, AH McKay, GA Shearer, CK AF Herd, CDK Treiman, AH McKay, GA Shearer, CK TI The behavior of Li and B during planetary basalt crystallization SO AMERICAN MINERALOGIST LA English DT Article ID YOUNG VOLCANIC-ROCKS; PLAGIOCLASE FELDSPAR; HYDROTHERMAL FLUIDS; PHASE-SEPARATION; MARTIAN MAGMAS; SILICATE MELTS; PARENT BODY; BORON; SHERGOTTITE; METEORITES AB Light-lithophile-element zoning patterns in pyroxene in the Shergotty and Zagami martian basaltic meteorites have previously been presented as evidence for pre-eruptive martian water. We investigate the partitioning of Li and B in martian igneous minerals experimentally, using a composition approximating that of the Queen Alexandria Range (QUE) 94201 martian basalt in one-atmosphere gas-mixing furnaces. Partition coefficients obtained for pyroxene (D-Li = 0.2, D-B = 0.023), plagioclase (D-Li = 0.37, D-B = 0.024), olivine (D-Li = 0.27, D-B = 0.007) and merrillite (D-Li = 0.7, D-B = 0.03), measured using Secondary Ion Mass Spectrometry of experimental charges, demonstrate that Li and B are incompatible in these minerals. As a test of our experimentally determined, anhydrous partition coefficients, we analyzed pyroxene in the Pasamonte eucrite, an asteroidal basalt with an anhydrous petrogenesis. Coupling of the partition coefficients with Pasamonte pyroxene analyses gives B parental melt concentrations in relative agreement with bulk rock analyses; however, Li parental melt concentrations and bulk analyses do not agree, suggestive of post-crystallization modification of Li zoning trends. Our results demonstrate that Li and B zoning patterns in pyroxene in martian basalts cannot be explained by the uptake of Li and B by co-crystallizing plagioclase, olivine, or merrillite, and suggest that the petrogeneses of Shergotty and Zagami involved something other than simple, one-atmosphere, anhydrous crystallization. C1 Lunar & Planetary Inst, Houston, TX 77058 USA. NASA, Johnson Space Ctr, Astromat Res Off, Houston, TX 77058 USA. Univ New Mexico, Inst Meteorit, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. RP Herd, CDK (reprint author), Univ Alberta, Dept Earth & Atmospher Sci, 1-26 Earth Sci Bldg, Edmonton, AB T6G 2E3, Canada. EM herd@ualberta.ca NR 45 TC 32 Z9 32 U1 0 U2 5 PU MINERALOGICAL SOC AMER PI WASHINGTON PA 1015 EIGHTEENTH ST, NW SUITE 601, WASHINGTON, DC 20036 USA SN 0003-004X J9 AM MINERAL JI Am. Miner. PD MAY-JUN PY 2004 VL 89 IS 5-6 BP 832 EP 840 PG 9 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 824IM UT WOS:000221680000018 ER PT J AU McLaughlin, WI Miller, SL AF McLaughlin, WI Miller, SL TI The shadow effect and the case of felix tisserand SO AMERICAN SCIENTIST LA English DT Article AB The most eminent astronomer who never came to popular attention was lost in the shadow of his countryman, Pierre-Simon Laplace. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Miller, SL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Sylvia.L.Miller@jpl.nasa.gov NR 11 TC 1 Z9 1 U1 0 U2 1 PU SIGMA XI-SCI RES SOC PI RES TRIANGLE PK PA PO BOX 13975, RES TRIANGLE PK, NC 27709 USA SN 0003-0996 J9 AM SCI JI Am. Scientist PD MAY-JUN PY 2004 VL 92 IS 3 BP 262 EP 267 DI 10.1511/2004.47.933 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 811SQ UT WOS:000220792000023 ER PT J AU Goffredi, SK Waren, A Orphan, VJ Van Dover, CL Vrijenhoek, RC AF Goffredi, SK Waren, A Orphan, VJ Van Dover, CL Vrijenhoek, RC TI Novel forms of structural integration between microbes and a hydrothermal vent gastropod from the Indian Ocean SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID WORM RIFTIA-PACHYPTILA; SULFATE-REDUCING BACTERIA; MID-ATLANTIC RIDGE; ALVINELLA-POMPEJANA; ELEMENTAL SULFUR; GALAPAGOS RIFT; DIVERSITY; IRON; DISPROPORTIONATION; PROTEOBACTERIA AB Here we describe novel forms of structural integration between endo- and episymbiotic microbes and an unusual new species of snail from hydrothermal vents in the Indian Ocean. The snail houses a dense population of gamma-proteobacteria within the cells of its greatly enlarged esophageal gland. This tissue setting differs from that of all other vent mollusks, which harbor sulfur-oxidizing endosymbionts in their gills. The significantly reduced digestive tract, the isotopic signatures of the snail tissues, and the presence of internal bacteria suggest a dependence on chemoautotrophy for nutrition. Most notably, this snail is unique in having a dense coat of mineralized scales covering the sides of its foot, a feature seen in no other living metazoan. The scales are coated with iron sulfides (pyrite and greigite) and heavily colonized by epsilon- and delta-proteobacteria, likely participating in mineralization of the sclerites. This novel metazoan-microbial collaboration illustrates the great potential of organismal adaptation in chemically and physically challenging deep-sea environments. C1 Monterey Bay Aquarium Res Inst, Moss Landing, CA 95039 USA. Swedish Museum Nat Hist, SE-10405 Stockholm, Sweden. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Coll William & Mary, Dept Biol, Williamsburg, VA 23187 USA. RP Goffredi, SK (reprint author), Monterey Bay Aquarium Res Inst, 7700 Sandholdt Rd, Moss Landing, CA 95039 USA. EM goffredi@mbari.org RI Orphan, Victoria/K-1002-2014 OI Orphan, Victoria/0000-0002-5374-6178 NR 49 TC 86 Z9 90 U1 2 U2 29 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 MAY PY 2004 VL 70 IS 5 BP 3082 EP 3090 DI 10.1128/AEM.70.5.3082-3090.2004 PG 9 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 819UD UT WOS:000221340400066 PM 15128570 ER PT J AU Boyle, R Bush, G Ehsanian, R AF Boyle, R Bush, G Ehsanian, R TI Input/output properties of the lateral vestibular nucleus SO ARCHIVES ITALIENNES DE BIOLOGIE LA English DT Article ID MEDIAL LONGITUDINAL FASCICULUS; SILVER IMPREGNATION METHODS; CEREBELLAR ANTERIOR VERMIS; INNERVATING OTOLITH ORGANS; CERVICAL-SPINAL-CORD; SQUIRREL-MONKEY; VESTIBULOSPINAL NEURONS; SECONDARY NEURONS; NERVE AFFERENTS; LINEAR ACCELERATION C1 NASA, Ames Res Ctr, BioVIS Technol Ctr, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Vestibular Res Facil, Moffett Field, CA 94035 USA. RP Boyle, R (reprint author), NASA, Ames Res Ctr, BioVIS Technol Ctr, M-S 239-11, Moffett Field, CA 94035 USA. EM richard.boyle@nasa.gov FU NINDS NIH HHS [NS27050] NR 93 TC 3 Z9 3 U1 0 U2 1 PU UNIV PISA PI PISA PA LUNGARNO A PACINOTTI 43, 56100 PISA, ITALY SN 0003-9829 J9 ARCH ITAL BIOL JI Arch. Ital. Biol. PD MAY PY 2004 VL 142 IS 3 BP 133 EP 153 PG 21 WC Neurosciences SC Neurosciences & Neurology GA 829QW UT WOS:000222065700002 PM 15260374 ER PT J AU Holden, BP Stanford, SA Eisenhardt, P Dickinson, M AF Holden, BP Stanford, SA Eisenhardt, P Dickinson, M TI Evolution in the color-magnitude relation of early-type galaxies in clusters of galaxies at z similar or equal to 1 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : elliptical and lenticular, cD; galaxies : evolution; galaxies : fundamental parameters; galaxies : photometry ID MEDIUM-SENSITIVITY SURVEY; ABSORPTION-LINE STRENGTHS; HIGH-REDSHIFT CLUSTERS; GROTH STRIP SURVEY; X-RAY DATA; LUMINOSITY FUNCTION; DISTANT CLUSTERS; ELLIPTIC GALAXIES; STELLAR POPULATIONS; E/S0 GALAXIES AB We present a study of the color evolution of elliptical and S0 galaxies in six clusters of galaxies inside the redshift range 0.78 < z < 1.27. For each cluster, we used imaging from the Hubble Space Telescope (HST) to determine morphological types of the galaxies. These types were determined both by an automated technique and from visual inspection. We performed simulations to determine the accuracy of the automated classifications and found a success rate of similar to75% at m(L-*) or brighter magnitudes for most of our HST imaging data with the fraction of late-type galaxies identified as early-type galaxies to be similar to 10% at m(L-*) to similar to 20% at m(L-* + 2). From ground-based optical and near-infrared imaging, we measured the zero point and scatter in the color-magnitude relation of the elliptical and S0 galaxy populations, which we combine with the 1998 sample of Stanford et al., yielding a sample of cluster early-type galaxies that span a look-back time of almost 9 Gyr from the present. We see the colors of the early-type cluster members become bluer with increasing redshift, as expected from passively evolving stellar populations. We fitted a set of models to the change in the color as a function of redshift, with the best-fitting values ranging from a formation redshift of 3(-1)(+2) to 5(-3), depending on the specific model used, though we find no dependence for the formation epoch on the metallicity of the populations. The large scatter in resulting formation epochs, which depends on the details of the models used, implies that the oldest stars in the elliptical galaxies appear to have formed at redshifts of z > 3. We find possible evolution in the scatter of the colors, with some high-redshift clusters showing scatter as small as the Coma Cluster but others showing much larger scatter. Those clusters with a small scatter imply either a formation redshift of at least z similar to 3 or a smaller spread in the range of formation redshifts at lower redshifts, assuming a Gaussian distribution of star formation around the mean epoch. C1 Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. RP Holden, BP (reprint author), Univ Calif Santa Cruz, Lick Observ, Mt Hamilton, CA 95140 USA. EM holden@ucolick.org; adam@igpp.ucllnl.org; prme@kromos.jpl.nasa.gov; med@stsci.edu NR 74 TC 72 Z9 74 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2004 VL 127 IS 5 BP 2484 EP 2510 DI 10.1086/382722 PG 27 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823BP UT WOS:000221585000002 ER PT J AU Arribas, S Bushouse, H Lucas, RA Colina, L Borne, KD AF Arribas, S Bushouse, H Lucas, RA Colina, L Borne, KD TI Optical imaging of very luminous infrared galaxy systems: Photometric properties and late evolution SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : interactions; galaxies : photometry; galaxies : starburst ID ULTRALUMINOUS IRAS GALAXIES; REDSHIFT SURVEY; STAR-FORMATION; LARGE-SAMPLE; 1-JY SAMPLE; MERGERS; SPECTROSCOPY; SPECTRA; NUCLEAR; BRIGHT AB A sample of 19 low-redshift (0.03 < z < 0.07), very luminous infrared galaxy [VLIRG: 10(11) L(.) < L(8-1000 mu m) < 10(12) L(.)] systems (30 galaxies) has been imaged in B, V, and I using ALFOSC with the Nordic Optical Telescope. These objects cover a luminosity range that is key to linking the most luminous infrared galaxies with the population of galaxies at large. As previous morphological studies have reported, most of these objects exhibit features similar to those found in ultraluminous infrared galaxies (ULIRGs), which suggests that they are also undergoing strong interactions or mergers. We have obtained photometry for all of these VLIRG systems, the individual galaxies ( when detached), and their nuclei, and the relative behavior of these classes has been studied in optical color-magnitude diagrams. The observed colors and magnitudes for both the systems and the nuclei lie parallel to the reddening vector, with most of the nuclei having redder colors than the galaxy disks. Typically, the nuclei compose 10% of the total flux of the system in B and 13% in I. The photometric properties of the sample are also compared with previously studied samples of ULIRGs. The mean observed optical colors and magnitudes agree well with those of cool ULIRGs. The properties of the nuclei also agree with those of warm ULIRGs, although the latter show a much larger scatter in both luminosity and color. Therefore, the mean observed photometric properties of VLIRG and ULIRG samples, considered as a whole, are indistinguishable at optical wavelengths. This suggests that not only ULIRGs, but also the more numerous population of VLIRGs, have similar rest-frame optical photometric properties to the submillimeter galaxies (SMGs), reinforcing the connection between low-z LIRGs and high-z SMGs. When the nuclei of the young and old interacting systems (classified according to a scheme based on morphological features) are considered separately, some differences between the VLIRG and the ULIRG samples are found. In particular, although the young VLIRGs and ULIRGs seem to share similar properties, the old VLIRGs are less luminous and redder than old ULIRG systems. If confirmed with larger samples, this behavior suggests that the late-stage evolution is different for VLIRGs and ULIRGs. Specifically, as suggested from spectroscopic data, the present photometric observations support the idea that the activity during the late phases of VLIRG evolution is dominated by starbursts, while a higher proportion of ULIRGs could evolve into a QSO type of object. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. CSIC, Inst Estructura Mat, E-28006 Madrid, Spain. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. George Mason Univ, Sch Computat Sci, Greenbelt, MD 20771 USA. RP Arribas, S (reprint author), European Space Agcy, ESTEC, Space Telescope Div, Noordwijk, Netherlands. EM arribas@stsci.edu; bushouse@stsci.edu; lucas@stsci.edu; colina@damir.iem.csic.es; borne@mail630.gsfc.nasa.gov NR 42 TC 37 Z9 37 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2004 VL 127 IS 5 BP 2522 EP 2543 DI 10.1086/386352 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823BP UT WOS:000221585000004 ER PT J AU Ramirez, SV Rebull, L Stauffer, J Hearty, T Hillenbrand, L Jones, B Makidon, R Pravdo, S Strom, S Werner, M AF Ramirez, SV Rebull, L Stauffer, J Hearty, T Hillenbrand, L Jones, B Makidon, R Pravdo, S Strom, S Werner, M TI Chandra X-ray observations of young clusters. I. NGC 2264 data SO ASTRONOMICAL JOURNAL LA English DT Article DE stars : activity; stars : pre-main-sequence; X-rays : stars ID MAIN-SEQUENCE STARS; INITIAL MASS FUNCTION; ORION NEBULA CLUSTER; SOLAR-TYPE STARS; T-TAURI STARS; NGC 2264; SKY SURVEY; INFRARED EXCESSES; HRI OBSERVATIONS; FORMING HISTORY AB We present results of a Chandra observation of a field in NGC 2264. The observations were taken with the ACIS-I camera with an exposure time of 48.1 ks. We present a catalog of 263 sources, which includes X-ray luminosity, optical and infrared photometry, and X-ray variability information. We found 41 variable sources, 14 of which have a flarelike light curve, and two of which have a pattern of a steady increase or decrease over a 10 hr period. The optical and infrared photometry for the stars identified as X-ray sources are consistent with most of these objects being pre-main-sequence stars with ages younger than 3 Myr. C1 CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Natl Opt Astron Observ, Kitt Peak Natl Observ, Tucson, AZ 85719 USA. RP Ramirez, SV (reprint author), CALTECH, Spitzer Sci Ctr, MS 220-06, Pasadena, CA 91125 USA. OI Rebull, Luisa/0000-0001-6381-515X NR 67 TC 37 Z9 37 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2004 VL 127 IS 5 BP 2659 EP 2673 DI 10.1086/383290 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823BP UT WOS:000221585000013 ER PT J AU Brown, TM Ferguson, HC Smith, E Kimble, RA Sweigart, AV Renzini, A Rich, RM AF Brown, TM Ferguson, HC Smith, E Kimble, RA Sweigart, AV Renzini, A Rich, RM TI RR Lyrae stars in the Andromeda halo from deep imaging with the Advanced Camera for Surveys SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : halos; galaxies : individual (M31); galaxies : stellar content; stars : variables : other ID DWARF SPHEROIDAL COMPANIONS; LARGE-MAGELLANIC-CLOUD; GLOBULAR-CLUSTERS; VARIABLE-STARS; METALLICITY DISTRIBUTION; SPECTRAL-ANALYSIS; LOCAL GROUP; SPACED DATA; M31 HALO; GALAXY AB We present a complete census of RR Lyrae stars in a halo field of the Andromeda galaxy. These deep observations, taken as part of a program to measure the star formation history in the halo, spanned a period of 41 days with sampling on a variety of timescales, enabling the identification of short- and long-period variables. Although the long-period variables cannot be fully characterized within the time span of this program, the enormous advance in sensitivity provided by the Advanced Camera for Surveys on the Hubble Space Telescope allows accurate characterization of the RR Lyrae population in this field. We find 29 RRab stars with a mean period of 0.594 days, 25 RRc stars with a mean period of 0.316 days, and one RRd star with a fundamental period of 0.473 days and a first-overtone period of 0.353 days. These 55 RR Lyrae stars imply a specific frequency S(RR) approximate to 5.6, which is large given the high mean metallicity of the halo, but not surprising given that these stars arise from the old, metal-poor tail of the distribution. This old population in the Andromeda halo cannot be clearly placed into one of the Oosterhoff types: the ratio of RRc/RRabc stars is within the range seen in Oosterhoff II globular clusters, the mean RRab period is in the gap between Oosterhoff types, and the mean RRc period is in the range seen in Oosterhoff I globular clusters. The periods of these RR Lyrae stars suggest a mean metallicity of [Fe/H] approximate to - 1.6, while their brightness implies a distance modulus to Andromeda of 24.5 +/- 0.1, in good agreement with the Cepheid distance. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. European So Observ, D-8046 Garching, Germany. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. RP Brown, TM (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. EM tbrown@stsci.edu; ferguson@stsci.edu; edsmith@stsci.edu; randy.a.kimble@nasa.gov; allen.v.sweigart@nasa.gov; arenzini@eso.org; rmr@astro.ucla.edu NR 46 TC 64 Z9 64 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2004 VL 127 IS 5 BP 2738 EP 2752 DI 10.1086/386355 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823BP UT WOS:000221585000018 ER PT J AU McCarthy, C Zuckerman, B AF McCarthy, C Zuckerman, B TI The brown dwarf desert at 75-1200 AU SO ASTRONOMICAL JOURNAL LA English DT Article DE binaries : general; stars : low-mass, brown dwarfs ID EXTRASOLAR GIANT PLANETS; MAIN-SEQUENCE STARS; SOLAR-TYPE STARS; ALL-SKY SURVEY; LOCAL ASSOCIATION; WIDE-FIELD; SAMPLE; AGE; COMPANIONS; IDENTIFICATION AB We present results of a comprehensive infrared coronagraphic search for substellar companions to nearby stars. The research consisted of (1) a 178-star survey at Steward and Lick observatories, with optical follow-up from Keck Observatory, capable of detecting companions with masses greater than 30 M-J, and semimajor axes between about 140 to 1200 AU; (2) a 102-star survey using the Keck Telescope, capable of detecting extrasolar brown dwarfs and planets typically more massive than 10 M-J, with semimajor axes between about 75 and 300 AU. Only one brown dwarf companion was detected, and no planets. The frequency of brown dwarf companions to G, K, and M stars orbiting between 75 and 300 AU is measured to be 1%+/-1%, the most precise measurement of this quantity to date. The frequency of massive (greater than 30 M-J) brown dwarf companions at 120-1200 AU is found to be f=0.7%+/-0.7%. The frequency of giant planet companions with masses between 5 and 10 M-J orbiting between 75 and 300 AU is measured here for the first time to be no more than similar to3%. Together with other surveys that encompass a wide range of orbital separations, these results imply that substellar objects with masses between 12 and 75 M-J form only rarely as companions to stars. Theories of star formation that could explain these data are only now beginning to emerge. C1 Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. NASA, Astrobiol Inst, Moffett Field, CA 94035 USA. RP McCarthy, C (reprint author), San Francisco State Univ, Dept Phys & Astron, 1600 Holloway Ave, San Francisco, CA 94132 USA. EM chris@stars.sfsu.edu; ben@astro.ucla.edu NR 48 TC 117 Z9 117 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2004 VL 127 IS 5 BP 2871 EP 2884 DI 10.1086/383559 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823BP UT WOS:000221585000028 ER PT J AU Hartman, H Gull, T Johansson, S Smith, N AF Hartman, H Gull, T Johansson, S Smith, N CA HST Eta Carinae Treasury Proj Team TI Identification of emission lines in the low-ionization strontium filament near Eta Carinae SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE line : identification; stars : circumstellar matter; stars : kinematics; stars : individual : Eta Carinac ID HOMUNCULUS-NEBULA; WEIGELT BLOBS; II EMISSION; SPECTROSCOPY; ULTRAVIOLET; EXCITATION; EJECTA; STIS; BD AB We have obtained deep spectra from 1640 to 10 100 A with the Space Telescope Imaging Spectrograph (STIS) of the strontium filament, a largely neutral emission nebulosity lying close to the very luminous star Eta Carinae and showing an uncommon spectrum. Over 600 emission lines, both permitted and forbidden, have been identified. The majority originates from neutral or singly-ionized iron group elements (Sc, Ti, V, Cr, Mn, Fe, Co, Ni). Sr is the only neutron capture element detected. The presence of Sr 11, numerous strong Ti 11 and V it lines and the dominance of Fe I over Fe it are notable discoveries. While emission lines of hydrogen, helium, and nitrogen are associable with other spatial Structures at other velocities within the Homunculus, no emission lines from these elements correspond to the spatial structure or velocity of the Sr filament. Moreover, no identified Sr filament emission line requires an ionization or excitation energy above approximately 8 eV. Ionized gas extends spatially along the aperture, oriented along the polar axis of the Homunculus, and in velocity around the strontium filament. We suggest that the strontium filament is shielded from ultraviolet radiation at energies above 8 eV, but is intensely irradiated by the central star at wavelengths longward of 1500 Angstrom. C1 Lund Univ, Lund Observ, S-22100 Lund, Sweden. Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Colorado, CASA, Boulder, CO 80309 USA. RP Hartman, H (reprint author), Lund Univ, Lund Observ, Box 43, S-22100 Lund, Sweden. EM henrik.hartman@astro.lu.se RI Gull, Theodore/D-2753-2012; Hartman, Henrik/K-3113-2013 OI Gull, Theodore/0000-0002-6851-5380; NR 26 TC 30 Z9 30 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2004 VL 419 IS 1 BP 215 EP 224 DI 10.1051/0004-6361:20035647 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 831RH UT WOS:000222213300021 ER PT J AU Mora, A Eiroa, C Natta, A Grady, CA de Winter, D Davies, JK Ferlet, R Harris, AW Miranda, LF Montesinos, B Oudmaijer, RD Palacios, J Quirrenbach, A Rauer, H Alberdi, R Cameron, A Deeg, HJ Garzon, F Horne, K Merin, B Penny, A Schneider, J Solano, E Tsapras, Y Wesselius, PR AF Mora, A Eiroa, C Natta, A Grady, CA de Winter, D Davies, JK Ferlet, R Harris, AW Miranda, LF Montesinos, B Oudmaijer, RD Palacios, J Quirrenbach, A Rauer, H Alberdi, R Cameron, A Deeg, HJ Garzon, F Horne, K Merin, B Penny, A Schneider, J Solano, E Tsapras, Y Wesselius, PR TI Dynamics of the circumstellar gas in the herbig ae stars BF orionis, SV cephei, WW vulpeculae and XY persei SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : pre-main sequence; stars : circumstellar matter; stars : individual : BF Ori, SV Cep, WW Vul, XY Per ID MAIN-SEQUENCE STARS; BETA-PICTORIS PHENOMENON; UX-ORIONIS; VEGA-TYPE; PHOTOPOLARIMETRIC ACTIVITY; AE/BE STARS; EXPORT; VARIABILITY; ACCRETION; SPECTRA AB We present high resolution (lambda/Deltalambda = 49 000) echelle spectra of the intermediate mass, pre-main sequence stars BF Ori, SV Cep, WW Wul and XY Per. The spectra cover the range 3800-5900 Angstrom and monitor the stars on time scales of months and days. All spectra show a large number of Balmer and metallic lines with variable blueshifted and redshifted absorption features superimposed to the photospheric stellar spectra. Synthetic Kurucz models are used to estimate rotational velocities, effective temperatures and gravities of the stars. The best photospheric models are subtracted from each observed spectrum to determine the variable absorption features due to the circumstellar gas; those features are characterized in terms of their velocity, v, dispersion velocity, Deltav, and residual absorption, R-max. The absorption components detected in each spectrum can be grouped by their similar radial velocities and are interpreted as the signature of the dynamical evolution of gaseous clumps with, in most cases, solar-like chemical composition. This infalling and outflowing gas has similar properties to the circumstellar gas observed in UX Ori, emphasizing the need for detailed theoretical models, probably in the framework of the magnetospheric accretion scenario, to understand the complex environment in Herbig Ae (HAe) stars. WW Vul is unusual because, in addition to infalling and outflowing gas with properties similar to those observed in the other stars, it shows also transient absorption features in metallic lines with no obvious counterparts in the hydrogen lines. This could, in principle, suggest the presence of CS gas clouds with enhanced metallicity around WW Vul. The existence of such a metal-rich gas component, however, needs to be confirmed by further observations and a more quantitative analysis. C1 Univ Autonoma Madrid, Dept Fis Teor C XI, E-28049 Madrid, Spain. Estec, ESA, Leiden, Netherlands. Leiden Univ, Leiden, Netherlands. Osserv Astrofis Arcetri, I-50125 Florence, Italy. NASA, Goddard Space Flight Ctr, STIS, Greenbelt, MD 20771 USA. TNO, TPD Space Instrumentat, NL-2600 AD Delft, Netherlands. Royal Observ, Astron Technol Ctr, Edinburgh, Midlothian, Scotland. CNRS, Inst Astrophys, F-75014 Paris, France. DLR, Dept Planetary Explorat, D-12489 Berlin, Germany. Inst Astrofis Andalucia, E-18080 Granada, Spain. LAEFF, VILSPA, E-28080 Madrid, Spain. Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. Univ Calif San Diego, Dept Phys, Ctr Space Sci & Astrophys, La Jolla, CA 92093 USA. Univ St Andrews, St Andrews KY16 9SS, Fife, Scotland. Inst Astrofis Canarias, E-38200 San Cristobal la Laguna, Spain. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Observ Paris, F-92195 Meudon, France. SRON, NL-9700 AV Groningen, Netherlands. RP Mora, A (reprint author), Univ Autonoma Madrid, Dept Fis Teor C XI, E-28049 Madrid, Spain. EM alcione.mora@uam.es RI Solano, Enrique/C-2895-2017; Montesinos, Benjamin/C-3493-2017; OI Montesinos, Benjamin/0000-0002-7982-2095; Cameron, Andrew/0000-0002-8863-7828; Deeg, Hans-Jorg/0000-0003-0047-4241; Merin, Bruno/0000-0002-8555-3012 NR 30 TC 19 Z9 19 U1 0 U2 1 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2004 VL 419 IS 1 BP 225 EP 240 DI 10.1051/0004-6361:20040096 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 831RH UT WOS:000222213300022 ER PT J AU Merin, B Montesinos, B Eiroa, C Solano, E Mora, A D'Alessio, P Calvet, N Oudmaijer, RD de Winter, D Davies, JK Harris, AW Cameron, A Deeg, HJ Ferlet, R Garzon, F Grady, CA Horne, K Miranda, LF Palacios, J Penny, A Quirrenbach, A Rauer, H Schneider, J Wesselius, PR AF Merin, B Montesinos, B Eiroa, C Solano, E Mora, A D'Alessio, P Calvet, N Oudmaijer, RD de Winter, D Davies, JK Harris, AW Cameron, A Deeg, HJ Ferlet, R Garzon, F Grady, CA Horne, K Miranda, LF Palacios, J Penny, A Quirrenbach, A Rauer, H Schneider, J Wesselius, PR TI Study of the properties and spectral energy distributions of the Herbig AeBe stars HD 34282 and HD 141569 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : pre-main sequence; stars : fundamental parameters; stars : planetary systems : protoplanetary disks ID T-TAURI STARS; MAIN-SEQUENCE STARS; INTERMEDIATE-MASS STARS; PARTICLE-SIZE DISTRIBUTION; VEGA-LIKE STARS; AE/BE STARS; ACCRETION DISKS; CIRCUMSTELLAR DISKS; INFRARED-EMISSION; YOUNG OBJECTS AB We present a study of the stellar parameters, distances and spectral energy distributions (SEDs) of HD 34282 and HD 141569, two pre-main sequence Herbig AeBe stars. Both objects have been reported to show "anomalous positions" in the HR diagram in the sense that they appear below the main sequence. A significant result of this work is that both stars arc metal-deficient. The Hipparcos distance of HD 34282 is very uncertain and the current study places the star at the expected evolutionary position in the HR diagram, i.e. as a PMS star. The distance for HD 141569 found in this work matches the Hipparcos distance, and the problem of its anomalous position is solved as a result of the low metallicity of the object: using the right metallicity tracks, the star is in the PMS region. The SEDs are constructed using data covering ultraviolet to millimetre wavelengths. Physical, non-parametric models, have been applied in order to extract some properties of the disks surrounding the stars. The disk around HD 34282 is accreting actively, it is massive and presents large grains in the mid-plane and small grains in the surface. HD 141569 has a very low mass disk, which is in an intermediate stage towards a debris-type disk. C1 LAEFF, E-28080 Madrid, Spain. Inst Astrofis Andalucia, CSIC, E-18080 Granada, Spain. Univ Autonoma Madrid, Dept Fis Teor, Fac Ciencias, E-28049 Madrid, Spain. Univ Nacl Autonoma Mexico, Ctr Radioastron & Astrofis, Morelia 58089, Michoacan, Mexico. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. TNO, TPD Space Instrumentat, NL-2600 AD Delft, Netherlands. Royal Observ, Astron Technol Ctr, Edinburgh EH9 3HJ, Midlothian, Scotland. DLR, Dept Planetary Explorat, D-12489 Berlin, Germany. Univ St Andrews, Dept Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. Inst Astrofis Canarias, E-38200 San Cristobal la Laguna, Spain. Inst Astrophys, CNRS, F-75014 Paris, France. NASA, Goddard Space Flight Ctr, NOAO, STIS, Greenbelt, MD 20771 USA. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Sterrewacht Leiden, NL-2300 RA Leiden, Netherlands. Observ Paris, F-92195 Meudon, France. Univ Groningen, SRON, NL-9700 AV Groningen, Netherlands. RP Merin, B (reprint author), LAEFF, Apartado 50727, E-28080 Madrid, Spain. EM bruno@laeff.esa.es RI Solano, Enrique/C-2895-2017; Montesinos, Benjamin/C-3493-2017; OI Montesinos, Benjamin/0000-0002-7982-2095; Cameron, Andrew/0000-0002-8863-7828; Deeg, Hans-Jorg/0000-0003-0047-4241; Merin, Bruno/0000-0002-8555-3012 NR 99 TC 62 Z9 62 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2004 VL 419 IS 1 BP 301 EP 318 DI 10.1051/0004-6361:20034561 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 831RH UT WOS:000222213300029 ER PT J AU Watson, D McBreen, B Hanlon, L Reeves, JN Smith, N Perlman, E Stocke, J Rector, RA AF Watson, D McBreen, B Hanlon, L Reeves, JN Smith, N Perlman, E Stocke, J Rector, RA TI XMM-Newton observations of the BL Lac MS 0205.7+3509: A dense, low-metallicity absorber SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : BL Lacertae objects : individual : MS 0205.7+3509; galaxies : active; X-rays : galaxies ID HUBBLE-SPACE-TELESCOPE; X-RAY-SPECTRUM; LACERTAE OBJECTS; GALAXY; AO-0235+164; QUASARS; ASCA AB The high-frequency-peaked BL Lac, MS 0205.7+3509 was observed twice with XMM-Newton. Both X-ray spectra are synchrotron-dominated, with mean 0.2-10 keV fluxes of 2.80 +/- 0.01 and 3.34 +/- 0.02 x 10(-12) erg cm(-2) s(-1). The X-ray spectra are well fit by a power-law with absorption above the Galactic value, however no absorption edges are detected, implying a low metallicity absorber (Z. = 0.04(-0.01)(+0.03)) or an absorber with redshift above one (best-fit z = 2.1 for an absorber with solar abundances). In either case the absorbing column density must be similar to9 x 10(21) cm(-2). A new optical spectrum is presented, with a Mg II absorption doublet detected at z = 0.351, but no other significant features. The optical spectrum shows little reddening, implying a low dust to gas ratio in the absorber. MS 0205.7+3509 must therefore be viewed through a high column density, low-metallicity gas cloud, probably at z = 0.351 and associated with the galaxy that has been shown to be within similar to2" of the BL Lac. C1 Univ Copenhagen, Niels Bohr Inst, Astron Observ, DK-2100 Copenhagen O, Denmark. Univ Leicester, Dept Phys & Astron, Xray Astron Grp, Leicester LE1 7RH, Leics, England. Natl Univ Ireland Univ Coll Dublin, Dept Expt Phys, Dublin 4, Ireland. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. Cork Inst Technol, Dept Appl Phys & Instrumentat, Cork, Ireland. Univ Maryland Baltimore Cty, Joint Ctr Astrophys, Baltimore, MD 21250 USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. Natl Opt Astron Observ, Tucson, AZ 85719 USA. Univ Alaska Anchorage, Anchorage, AK 99508 USA. RP Univ Copenhagen, Niels Bohr Inst, Astron Observ, Juliane Maries Vej 30, DK-2100 Copenhagen O, Denmark. EM darach@astro.ku.dk RI Watson, Darach/E-4521-2015 OI Watson, Darach/0000-0002-4465-8264 NR 27 TC 5 Z9 5 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2004 VL 418 IS 2 BP 459 EP 463 DI 10.1051/0004-6361:20034524 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 824ER UT WOS:000221669200008 ER PT J AU Perrin, G Ridgway, ST du Foresto, VC Mennesson, B Traub, WA Lacasse, MG AF Perrin, G Ridgway, ST du Foresto, VC Mennesson, B Traub, WA Lacasse, MG TI Interferometric observations of the supergiant stars alpha Orionis and alpha Herculis with FLUOR at IOTA SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : supergiants; infrared : stars; techniques : interferometric ID INFRARED ANGULAR DIAMETER; STELLAR INTERFEROMETRY; DUST; VISIBILITIES; GIANTS; MODELS; CALIBRATION; CETI AB We report the observations in the K band of the red supergiant star alpha Orionis and of the bright giant star alpha Herculis with the FLUOR beamcombiner at the IOTA interferometer. The high quality of the data allows us to estimate limb-darkening and derive precise diameters in the K band which combined with bolometric fluxes yield effective temperatures. In the case of Betelgeuse, data collected at high spatial frequency although sparse are compatible with circular symmetry and there is no clear evidence for departure from circular symmetry. We have combined the K band data with interferometric measurements in the L band and at 11.15 mum. The full set of data can be explained if a 2055 K layer with optical depths tau(K) = 0.060 +/- 0.003, tau(L) = 0.026 +/- 0.002 and tau(11.15 mum) = 2.33 +/- 0.23 is added 0.33 R-star above the photosphere providing a first consistent view of the star in this range of wavelengths. This layer provides a consistent explanation for at least three otherwise puzzling observations: the wavelength variation of apparent diameter, the dramatic difference in limb darkening between the two supergiant stars, and the previously noted reduced effective temperature of supergiants with respect to giants of the same spectral type. Each of these may be simply understood as an artifact due to not accounting for the presence of the upper layer in the data analysis. This consistent picture can be considered strong support for the presence of a sphere of warm water vapor, proposed by Tsuji (2000) when interpreting the spectra of strong molecular lines. C1 Observ Paris, LESIA, UMR 8109, F-92190 Meudon, France. Natl Opt Astron Observ, Tucson, AZ 85726 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Perrin, G (reprint author), Observ Paris, LESIA, UMR 8109, F-92190 Meudon, France. EM guy.perrin@obspm.fr NR 37 TC 79 Z9 79 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2004 VL 418 IS 2 BP 675 EP 685 DI 10.1051/0004-6361:20040052 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 824ER UT WOS:000221669200027 ER PT J AU Prinja, RK Rivinius, T Stahl, O Kaufer, A Foing, BH Cami, J Orlando, S AF Prinja, RK Rivinius, T Stahl, O Kaufer, A Foing, BH Cami, J Orlando, S TI Photospheric and stellar wind variability in epsilon Ori (B0 Ia) SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : early-type; stars : individual : epsilon Ori; stars : mass-loss; stars : oscillations ID EARLY-TYPE STARS; LINE-PROFILE VARIATIONS; FREQUENCY G-MODES; TIME-SERIES; CIRCUMSTELLAR ACTIVITY; NONRADIAL PULSATION; B-SUPERGIANTS; SUPER-GIANTS; MU-CENTAURI; O-STARS AB We provide direct observational evidence for a link between photospheric activity and perturbations in the dense inner-most stellar wind regions of the B supergiant star epsilon Ori. The results, which are relevant to our understanding of the origin of wind structure, are based on a multi-spectral line analysis of optical time-series data secured in 1998 using the HEROS spectrograph on the ESO Dutch 0.9-m telescope in La Silla. A period of similar to1.9 days is consistently identified in Balmer, He I absorption, and weak metal lines such as Si III and C it. The primary characteristic is a large-amplitude swaying of the central absorption trough of the line, with differential velocities in lines formed at varying depths in the atmosphere. The variance resulting from the "S-wave" velocity behaviour of the lines is constrained within the projected rotation velocity (similar to80 km s(-1)) in the weakest absorption lines, but extends blue-ward to over -200 km s(-1) in Halpha. A second (superimposed) 1.9 day signal is present at more extended blue-ward velocities (to similar to-300 km s(-1)) in lines containing stronger circumstellar components. Inspection of archival optical data from 1996 provides evidence that this modulation signal has persisted for at least 2.5 years. Non-radial pulsational modelling is carried out in an attempt to reproduce the key observational characteristics of the line profile variability. Only limited success is obtained with prograde (m = -1) modes. The principal S-wave pattern cannot be matched by these models and remains enigmatic. C1 UCL, Dept Phys & Astron, London WC1E 6BT, England. Landessternwarte Heidelberg, D-69117 Heidelberg, Germany. European So Observ, Santiago 19, Chile. ESA, RSSD, ESTEC SCISR, Res Support Div, NL-2200 AG Noordwijk, Netherlands. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Osserv Astron Palermo, INAF, Palermo, Italy. RP Prinja, RK (reprint author), UCL, Dept Phys & Astron, Gower St, London WC1E 6BT, England. EM rkp@star.ucl.ac.uk NR 33 TC 14 Z9 14 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2004 VL 418 IS 2 BP 727 EP 736 DI 10.1051/0004-6361:20035638 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 824ER UT WOS:000221669200032 ER PT J AU Revnivtsev, M Sazonov, S Jahoda, K Gilfanov, M AF Revnivtsev, M Sazonov, S Jahoda, K Gilfanov, M TI RXTE all-sky slew survey. Catalog of X-ray sources at vertical bar b vertical bar > 10 degrees SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE X-rays : general; catalogs; surveys ID MEDIUM-SENSITIVITY SURVEY; LOUD ACTIVE GALAXIES; TEMPERATURE FUNCTION; SOURCE COUNTS; GIS CATALOG; SAMPLE; CLUSTERS; NUCLEI; IDENTIFICATIONS; EMISSION AB We report results of a serendipitous hard X-ray (3-20 keV), nearly all-sky (\b\ > 10degrees) survey based on RXTF/PCA observations performed during satellite reorientations in 1996-2002. The survey is 80% (90%) complete to a 4sigma limiting flux of approximate to1.8 (2.5) x 10(-11) erg s(-1) cm(-2) in the 3-20 keV band. The achieved sensitivity in the 3-8 keV and 8-20 keV subbands is similar to and an order of magnitude higher than that of the previously record HEAO-1 A1 and HEAO-1 A4 all-sky surveys, respectively. A combined 7 x 10(3) sq deg area of the sky is sampled to flux levels below 10(-11) erg s(-1) cm(-2) (3-20 keV). In total 294 sources are detected and localized to better than 1 deg. 236 (80%) of these can be confidently associated with a known astrophysical object; another 22 likely result from the superposition of 2 or 3 closely located known sources. 35 detected sources remain unidentified, although for 12 of these we report a likely soft X-ray counterpart from the ROSAT all-sky survey bright source catalog. Of the reliably identified sources, 63 have local origin (Milky Way, LMC or SMC), 64 are clusters of galaxies and 100 are active galactic nuclei (AGN). The fact that the unidentified X-ray sources have hard spectra suggests that the majority of them are AGN, including highly obscured ones (N-H > 10(23) cm(-2)). For the first time we present a log N- log S diagram for extragalactic sources above 4 x 10(-12) erg s(-1) cm(-2) at 8-20 keV. C1 Max Planck Inst Astrophys, D-85740 Garching, Germany. Russian Acad Sci, Space Res Inst, Moscow 117997, Russia. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Revnivtsev, M (reprint author), Max Planck Inst Astrophys, Karl Schwarzschild Str 1, D-85740 Garching, Germany. EM mikej@mpa-garching.mpg.de RI Jahoda, Keith/D-5616-2012 NR 38 TC 92 Z9 94 U1 0 U2 1 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2004 VL 418 IS 3 BP 927 EP 936 DI 10.1051/0004-6361:20035798 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823XB UT WOS:000221646300015 ER PT J AU Bautista, MA Mendoza, C Kallman, TR Palmeri, P AF Bautista, MA Mendoza, C Kallman, TR Palmeri, P TI K-shell photoionization and electron impact excitation of Fe XVII-Fe XXIII SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE atomic data; atomic processes; line : formation ID R-MATRIX METHOD; GENERAL PROGRAM; VACANCY STATES; ATOMIC STRUCTURES; CROSS-SECTIONS; SCATTERING; IONS; IRON AB Photoabsorption cross sections across the K edge of Fe XVII-Fe XXIII and electron impact K-shell excitation effective collision strengths in Fe XVIII-Fe XXIII have been computed with the Breit-Pauli R-matrix method. The target models are represented with all the fine-structure levels within the n=2 complex, built up from single-electron orbital bases obtained in a Thomas-Fermi-Dirac statistical model potential. The effects of radiation and spectator Auger dampings are taken into account by means of an optical potential. In photoabsorption, these effects cause the resonances converging to the K thresholds to display symmetric profiles of constant width that smear the edge, with important implications in spectral analysis. In collisional excitation, they attenuate resonances making their contributions to the effective collision strength practically negligible. C1 Inst Venezolano Invest Cient, Ctr Fis, Caracas 1020A, Venezuela. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Bautista, MA (reprint author), Inst Venezolano Invest Cient, Ctr Fis, POB 21827, Caracas 1020A, Venezuela. EM bautista@kant.ivic.ve NR 31 TC 27 Z9 27 U1 0 U2 2 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2004 VL 418 IS 3 BP 1171 EP 1178 DI 10.1051/0004-6361:20034198 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 823XB UT WOS:000221646300034 ER PT J AU Ogle, PM Mason, KO Page, MJ Salvi, NJ Cordova, FA McHardy, IM Priedhorsky, WC AF Ogle, PM Mason, KO Page, MJ Salvi, NJ Cordova, FA McHardy, IM Priedhorsky, WC TI Relativistic OVIII emission and ionized outflow in NGC 4051 measured with XMM-Newton SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 4051); X-rays : galaxies ID SEYFERT 1 GALAXIES; ACTIVE GALACTIC NUCLEI; DUSTY WARM ABSORBER; REFLECTION GRATING SPECTROMETER; HOLE ACCRETION DISKS; NARROW-LINE REGION; X-RAY SPECTROSCOPY; BLACK-HOLE; ASCA OBSERVATIONS; SPECTRAL VARIABILITY AB We present XMM-Newton Reflection Grating Spectrometer observations of the soft X-ray spectrum of NGC 4051 and explore their implications for the inner accretion disk and ionized outflow in the active galactic nucleus. We fit the soft X-ray excess with a relativistically broadened O VIII recombination spectrum, including the entire line series and recombination continuum. This plus an underlying power-law continuum provides a much better fit to the soft X-ray spectrum than a single temperature or disk blackbody plus power law. The emission-line profiles, computed for a Kerr metric around a maximally rotating black hole, reveal a sharply peaked disk emissivity law and inner radius smaller than 1.7RG. The spectrum also includes narrow absorption and emission lines from C, N, O, Ne, and Fe in an ionized outflow. Outflow column densities are relatively low and do not create significant edges in the spectrum. The small amount of absorption bolsters confidence in the detection of relativistic emission-line features. The narrow- line emitter has a large (76%) global covering fraction, leading to strong forbidden lines and filling in of the resonance absorption lines. We also find broad C vi Lyalpha and very broad O VII emission from the broad-line region. The narrow-and broad-line regions span large ranges in ionization parameter and may arise in a disk outflow. The ionized absorber has a large ionization range, which is inconsistent with pressure equilibrium in a multiphase medium. The mass outflow rate exceeds the accretion rate by a factor of 1000. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Univ Calif Riverside, Riverside, CA 92521 USA. Univ Southampton, Southampton, Hants, England. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Ogle, PM (reprint author), CALTECH, Jet Prop Lab, MS 238-332,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM pmo@sgra.jpl.nasa.gov OI Priedhorsky, William/0000-0003-0295-9138 NR 70 TC 62 Z9 62 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2004 VL 606 IS 1 BP 151 EP 167 DI 10.1086/382744 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 813SC UT WOS:000220925800013 ER PT J AU Andersson, BG Knauth, DC Snowden, SL Shelton, RL Wannier, PG AF Andersson, BG Knauth, DC Snowden, SL Shelton, RL Wannier, PG TI A hot envelope around the Southern Coalsack: X-ray and far-ultraviolet observations SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : clouds; ISM : individual (Coalsack); ultraviolet : ISM; X-rays : ISM ID SPECTROSCOPIC-EXPLORER OBSERVATIONS; HIGH-RESOLUTION OBSERVATIONS; LOCAL INTERSTELLAR-MEDIUM; MILKY-WAY; THERMAL CONDUCTION; SUPERNOVA-REMNANTS; SCORPIO-CENTAURUS; MOLECULAR CLOUDS; GALACTIC HALO; CO SURVEY AB We present Far Ultraviolet Spectroscopic Explorer and ROSAT X-ray observations toward the Southern Coalsack. An almost complete X-ray halo can be seen around the cloud in the 0.75 and 1.5 keV images, and most of the observed stars show O vi absorption. Both the cloud and the stars have highly accurate distance determinations, allowing us to reliably place the stars and the cloud relative to each other. Using these distance determinations, we find no O vi - bearing gas in the foreground of the Coalsack, while for stars in the background of the cloud, O vi absorption is the norm. The column density of O vi correlates with the 0.75 and 1.5 keV intensities. These results suggest that the X-ray - emitting hot plasma is associated with the dense cloud. We propose that the heating of the Coalsack envelope is due to the hot gas in the interior of the Upper Cen-Lup superbubble. The Coalsack interaction region provides a nearby example of the hot-cold gas interfaces thought to be responsible for the O vi absorptions seen on many sight lines throughout the Galaxy. C1 Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Andersson, BG (reprint author), Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA. EM bg@pha.jhu.edu; dknauth@pha.jhu.edu; snowden@riva.gsfc.nasa.gov; shelton@pha.jhu.edu; peter.wannier@jpl.nasa.gov RI Snowden, Steven/D-5292-2012; OI Andersson, B-G/0000-0001-6717-0686 NR 60 TC 9 Z9 9 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2004 VL 606 IS 1 BP 341 EP 352 DI 10.1086/382861 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 813SC UT WOS:000220925800029 ER PT J AU Feng, H Li, TP Zhang, SN AF Feng, H Li, TP Zhang, SN TI Diagnostics of neutron star and black hole X-ray binaries with X-ray shot widths SO ASTROPHYSICAL JOURNAL LA English DT Article DE black hole physics; methods : data analysis; stars : neutron; X-rays : binaries; rays : stars ID FREQUENCY-RESOLVED SPECTROSCOPY; CYGNUS X-1; FAST VARIABILITY; POWER SPECTRA; TIME-DOMAIN; MODEL; PULSATIONS; EMISSION; NOISE; DISKS AB A statistic, w, the differential coefficient of the mean absolute difference of an observed light curve, is proposed for timescale analysis of shot widths. The shortest width of random shots can be measured by the position of the lower cutoff in the timescale spectrum of w. We use the statistic to analyze X-ray light curves from a sample of neutron star and black hole binaries, and the results show that the timescale analysis can help us distinguish between neutron star binaries and black hole binaries. The analysis can further reveal the structure and dynamics of accretion disks around black holes. C1 Tsing Hua Univ, Ctr Astrophys, Dept Engn & Phys, Beijing 100084, Peoples R China. Tsing Hua Univ, Ctr Astrophys, Dept Phys, Beijing 100084, Peoples R China. Chinese Acad Sci, Inst High Energy Phys, Lab Particle Astrophys, Beijing 100039, 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. RP Feng, H (reprint author), Tsing Hua Univ, Ctr Astrophys, Dept Engn & Phys, Beijing 100084, Peoples R China. NR 30 TC 6 Z9 8 U1 1 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 MAY 1 PY 2004 VL 606 IS 1 BP 424 EP 429 DI 10.1086/382948 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 813SC UT WOS:000220925800035 ER PT J AU Lee, CF Sahai, R AF Lee, CF Sahai, R TI Magnetohydrodynamic models of the bipolar knotty jet in Henize 2-90 SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : AGB and post-AGB; stars : winds, outflows ID EXCITATION PLANETARY-NEBULAE; MAGNETIZED JETS; PROPER MOTIONS; STELLAR JETS; MASS-LOSS; FLOWS; PROPAGATION; EVOLUTION; ACCRETION; SYSTEMS AB A remarkably linear, bipolar, knotty jet was recently discovered in Hen 2-90, an object classified as a young planetary nebula. Using two-dimensional, magnetohydrodynamic simulations, we investigate periodic variations in jet density and velocity as the mechanism for producing the jet and its knotty structures. From a detailed comparison between the Halpha emission derived from our models and the observations, we find that a nonmagnetized jet with density or velocity variations does not reproduce in detail the observed structure of the Hen 2-90 jet-a magnetized jet with periodic velocity variations is required. This jet has a radius of 125 AU, an average velocity of 300 km s(-1) with periodic variations (period = 43 yr) in the jet velocity of amplitude +/-15 km s(-1), and a toroidal magnetic field with a characteristic strength of 0.6 mG. The average mass-loss rate in the jet has decreased by about a factor of 3 in 600 yr (i.e., from 4.7 x 10(-7) M. yr(-1) at 20" to 1.7 x 10(-7) M. yr(-1) at 1" from the center along the jet axis). The progenitor asymptotic giant branch wind is assumed to have a mass-loss rate of 1.5 x 10(-6) M. yr(-1) (derived from the round, tenuous, Halpha halo surrounding the central source) and a typical expansion velocity of 10 km s(-1). We find a fairly detailed similarity in the physical properties of the jet in Hen 2-90 with that in the young stellar object HH 34. This similarity suggests that the jets in both objects may be launched in a similar manner, namely, from an accretion disk, despite the fact that these objects are at very different evolutionary stages. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, CF (reprint author), CALTECH, Jet Prop Lab, MS 183-900,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM chin-fei.lee@jpl.nasa.gov; raghvendra.sahai@jpl.nasa.gov NR 31 TC 14 Z9 14 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2004 VL 606 IS 1 BP 483 EP 496 DI 10.1086/381677 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 813SC UT WOS:000220925800041 ER PT J AU Shaposhnikov, N Titarchuk, L AF Shaposhnikov, N Titarchuk, L TI On the nature of the flux variability during an expansion stage of a type I X-ray burst: Constraints on neutron star parameters for 4U 1820-30 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; stars : fundamental parameters; stars : individual (4U 1820-30); X-rays : bursts ID PHOTOSPHERIC RADIUS EXPANSION; MASS; SPECTRA; MODELS AB We investigate closely the flux profile during the burst expansion stage observed from 4U 1820 - 30 with the Rossi X-Ray Timing Explorer on 1997 May 2. We are able to uncover the behavior of a photospheric radius and to simulate the evolution of the neutron star (NS) accretion disk system. We argue that although the bolometric luminosity is always the Eddington value L(Edd), the photon flux at the bottom of the expanded envelope can decrease during the expansion stage. In fact, at the initial moment of explosion when the bottom burning temperature is similar to2 x 10(9) K, the bottom flux L(bot) is a few times the Eddington limit, because the electron cross section is a few times less than the Thomson cross section at such high temperatures. The surplus of energy flux with respect to the Eddington, L(bot) - L(Edd), goes into the potential energy of the expanded envelope. As cooling of the burning zone starts the surplus decreases, and thus the envelope shrinks while the emergent photon flux stays the same, L = L(Edd). At a certain moment the NS low hemisphere, previously screened by the disk, becomes visible to the observer. Consequently, the flux detected by the observer increases. We estimate the anisotropy due to geometry and find that the system should have a high inclination angle. Finally, we apply an analytical model of X-ray spectral formation in the NS atmosphere during the burst decay stage to infer the NS mass-radius relation. C1 George Mason Univ, Sch Computat Sci, CEOSR, Fairfax, VA 22030 USA. George Mason Univ, CEOSR, NRL, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Shaposhnikov, N (reprint author), George Mason Univ, Sch Computat Sci, CEOSR, Fairfax, VA 22030 USA. EM nshaposh@scs.gmu.edu; lev@xip.nrl.navy.mil NR 19 TC 20 Z9 20 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2004 VL 606 IS 1 BP L57 EP L60 DI 10.1086/421015 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 813SD UT WOS:000220925900015 ER PT J AU Scott, JE Kriss, GA Lee, JC Arav, N Ogle, P Roraback, K Weaver, K Alexander, T Brotherton, M Green, RF Hutchings, J Kaiser, ME Marshall, H Oegerle, W Zheng, W AF Scott, JE Kriss, GA Lee, JC Arav, N Ogle, P Roraback, K Weaver, K Alexander, T Brotherton, M Green, RF Hutchings, J Kaiser, ME Marshall, H Oegerle, W Zheng, W TI Intrinsic absorption in the spectrum of markarian 279: Simultaneous Chandra, FUSE, and STIS observations SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE galaxies : active; galaxies : individual (Markarian 279); galaxies : Seyfert; quasars : absorption lines; ultraviolet : galaxies; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; HUBBLE-SPACE-TELESCOPE; SPECTROSCOPIC-EXPLORER OBSERVATIONS; SPECTROGRAPH ECHELLE OBSERVATIONS; ULTRAVIOLET EMISSION PROPERTIES; HIGH-RESOLUTION SPECTROSCOPY; IONIZED INTERSTELLAR-MEDIUM; SEYFERT-1 GALAXY NGC-3783; X-RAY-ABSORPTION; PHYSICAL CONDITIONS AB We present a study of the intrinsic X-ray and far-ultraviolet absorption in the Seyfert 1.5 galaxy Markarian 279 using simultaneous observations from the Chandra X-ray Observatory, the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope, and the Far Ultraviolet Spectroscopic Explorer ( FUSE). We also present FUSE observations made at three additional epochs. We detect the Fe Kalpha emission line in the Chandra spectrum, and its flux is consistent with the low X-ray continuum flux level of Mrk 279 at the time of the observation. Because of low signal-to-noise ratios (S/N) in the Chandra spectrum, no O VII or O VIII absorption features are observable in the Chandra data, but the UV spectra reveal strong and complex absorption from H I and high-ionization species such as O vi, N v, and C iv, as well as from low-ionization species such as C III, N III, C II, and N II in some velocity components. The far-UV spectral coverage of the FUSE data provides information on high-order Lyman series absorption, which we use to calculate the optical depths and line and continuum covering fractions in the intrinsic H I absorbing gas in a self-consistent fashion. The UV continuum flux of Mrk 279 decreases by a factor of similar to 7.5 over the time spanning these observations and we discuss the implications of the response of the absorption features to this change. From arguments based on the velocities, profile shapes, covering fractions and variability of the UV absorption, we conclude that some of the absorption components, particularly those showing prominent low-ionization lines, are likely associated with the host galaxy of Mrk 279, and possibly with its interaction with a close companion galaxy, while the remainder arises in a nuclear outflow. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Johns Hopkins Univ, Dept Phys & Astron, Ctr Astrophys Sci, Baltimore, MD 21218 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Weizmann Inst Sci, IL-76100 Rehovot, Israel. Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. Kitt Peak Natl Observ, Natl Opt Astron Observ, Tucson, AZ 85726 USA. Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, BC V9E 2E7, Canada. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Scott, JE (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. EM jescott@stsci.edu; gak@stsci.edu; jlee@space.mit.edu; arav@colorado.edu; pmo@sgra.jpl.nasa.gov; roraback@space.mit.edu; kweaver@cleo.gsfc.nasa.gov; tal.alexander@weizmann.ac.il; mbrother@uwyo.edu; rgreen@noao.edu; john.hutchings@hia.nrc.ca; kaiser@pha.jhu.edu; hermanm@space.mit.edu; oegerle@uvo.gsfc.nasa.gov; zheng@pha.jhu.edu RI Oegerle, William/C-9070-2012; Lee, Julia/G-2381-2015 OI Lee, Julia/0000-0002-7336-3588 NR 87 TC 40 Z9 40 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 2004 VL 152 IS 1 BP 1 EP 27 DI 10.1086/382748 PG 27 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 813SB UT WOS:000220925700001 ER PT J AU Tolls, V Melnick, GJ Ashby, MLN Bergin, EA Gurwell, MA Kleiner, SC Patten, BM Plume, R Stauffer, JR Wang, Z Zhang, YF Chin, G Erickson, NR Snell, RL Goldsmith, PF Neufeld, DA Schieder, R Winnewisser, G AF Tolls, V Melnick, GJ Ashby, MLN Bergin, EA Gurwell, MA Kleiner, SC Patten, BM Plume, R Stauffer, JR Wang, Z Zhang, YF Chin, G Erickson, NR Snell, RL Goldsmith, PF Neufeld, DA Schieder, R Winnewisser, G TI Submillimeter Wave Astronomy Satellite performance on the ground and in orbit SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE instrumentation : detectors; instrumentation : spectrographs; radio lines : general; submillimeter; techniques : spectroscopic; telescopes ID WATER-VAPOR; SPECTROMETER AB The Submillimeter Wave Astronomy Satellite (SWAS), which was launched in 1998 December, is a NASA mission dedicated to the study of interstellar chemistry and star formation. SWAS is conducting pointed observations of molecular clouds throughout our Galaxy in either the ground state or a low-lying transition of five astrophysically important species: O-2, C I, H-2 O-18, (CO)-C-13, and H-2 O-16 at approximately 487, 492, 548, 551, and 557 GHz, respectively. The SWAS instrument is comprised of a 54 cm x 68 cm off-axis Cassegrain telescope feeding two independent heterodyne receivers with Schottky barrier diode mixers, passively cooled to about 175 K. An Acousto-Optical Spectrometer (AOS) provides similar to 1 MHz (0.6 km s(-1)) frequency resolution and 1400 MHz (840 km s(-1)) total bandwidth with 350MHz (210 km s(-1)) per line for spectral analysis. SWAS was fully characterized during ground-based testing, and all performance parameters were verified on-orbit. During its on-orbit operation, SWAS observed more than 200 astronomical objects with more than 5000 lines of sight. This paper describes the tests conducted and compares the ground-based test results with the on-orbit test results. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Cornell Univ, Natl Astron & Ionosphere Ctr, Ithaca, NY 14853 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Cologne, Inst Phys 1, D-50937 Cologne, Germany. RP Tolls, V (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM vtolls@cfa.harvard.edu RI Chin, Gordon/E-1520-2012; Goldsmith, Paul/H-3159-2016 NR 19 TC 15 Z9 16 U1 0 U2 2 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 MAY PY 2004 VL 152 IS 1 BP 137 EP 162 DI 10.1086/382507 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 813SB UT WOS:000220925700009 ER PT J AU Mumm, E Farritor, S Pirjanian, P Leger, C Schenker, P AF Mumm, E Farritor, S Pirjanian, P Leger, C Schenker, P TI Planetary cliff descent using cooperative robots SO AUTONOMOUS ROBOTS LA English DT Article DE planetary exploration; robots for planetary exploration; cooperating robots; tethers; cliff decent; behavior AB Future robotic planetary exploration will need to traverse geographically diverse and challenging terrain. Cliffs, ravines, and fissures are of great scientific interest because they may contain important data regarding past water flow and past life. Highly sloped terrain is difficult and often impossible to safely navigate using a single robot. This paper describes a control system for a team of three robots that access cliff walls at inclines up to 70degrees. Two robot assistants, or anchors, lower a third robot, called the rappeller, down the cliff using tethers. The anchors use actively controlled winches to first assist the rappeller in navigation about the cliff face and then retreat to safe ground. This paper describes the coordination of these three robots so they function as a team to explore the cliff face. Stability requirements for safe operation are identified and a behavior-based control scheme is presented. Behaviors are defined for the system and command fusion methods are described. Controller stability and sensitivity are examined. System performance is evaluated with simulation, a laboratory system, and testing in field environments. C1 Univ Nebraska, Dept Mech Engn, Lincoln, NE 68588 USA. Evolut Robot, Pasadena, CA 91103 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mumm, E (reprint author), Univ Nebraska, Dept Mech Engn, Lincoln, NE 68588 USA. EM sfarritor@unl.edu NR 23 TC 16 Z9 17 U1 0 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0929-5593 J9 AUTON ROBOT JI Auton. Robot. PD MAY PY 2004 VL 16 IS 3 BP 259 EP 272 DI 10.1023/B:AURO.0000025790.37415.83 PG 14 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA 816IC UT WOS:000221102600002 ER PT J AU Sujan, VA Dubowsky, S Huntsberger, T Aghazarian, H Cheng, Y Schenker, P AF Sujan, VA Dubowsky, S Huntsberger, T Aghazarian, H Cheng, Y Schenker, P TI An architecture for distributed environment sensing with application to robotic cliff exploration SO AUTONOMOUS ROBOTS LA English DT Article DE cooperative robots; visual exploration; information theory; data fusion; robot communication ID SIMULTANEOUS LOCALIZATION AB Future planetary exploration missions will use cooperative robots to explore and sample rough terrain. To succeed robots will need to cooperatively acquire and share data. Here a cooperative multi-agent sensing architecture is presented and applied to the mapping of a cliff surface. This algorithm efficiently repositions the systems' sensing agents using an information theoretic approach and fuses sensory information using physical models to yield a geometrically consistent environment map. This map is then distributed among the agents using an information based relevant data reduction scheme. Experimental results for cliff face mapping using the JPL Sample Return Rover (SRR) are presented. The method is shown to significantly improve mapping efficiency over conventional methods. C1 MIT, Dept Mech Engn, Cambridge, MA 02139 USA. CALTECH, Jet Prop Lab, Mobil Syst Concept Dev Sect, Pasadena, CA 91109 USA. RP Sujan, VA (reprint author), MIT, Dept Mech Engn, Cambridge, MA 02139 USA. EM vasujan@alum.mit.edu NR 33 TC 7 Z9 7 U1 0 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0929-5593 J9 AUTON ROBOT JI Auton. Robot. PD MAY PY 2004 VL 16 IS 3 BP 287 EP 311 DI 10.1023/B:AURO.0000025792.60972.f2 PG 25 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA 816IC UT WOS:000221102600004 ER PT J AU Stocks, JM Taylor, NAS Tipton, MJ Greenleaf, JE AF Stocks, JM Taylor, NAS Tipton, MJ Greenleaf, JE TI Human physiological responses to cold exposure SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Review DE thermoregulation; cold immersion; hypothermia; cold shock; thermogenesis; skin blood flow; shivering ID SKIN BLOOD-FLOW; WATER IMMERSION; ACCIDENTAL HYPOTHERMIA; BODY TEMPERATURES; THERMAL RESPONSES; MENSTRUAL-CYCLE; THERMOREGULATORY RESPONSES; SHIVERING THERMOGENESIS; ENVIRONMENTAL CONDITIONS; METABOLIC-RESPONSES AB Thermal energy is transferred within and between bodies via several avenues, but for most unprotected human cold exposures, particularly during immersion, convective heat loss dominates. Lower tissue temperatures stimulate thermoreceptors, and the resultant afferent flow elicits autonomic homoeostatic responses (thermogenesis and vasoconstriction) that regulate body temperature within a narrow range. The most powerful effector responses occur when both superficial and deep thermoreceptors are cooled simultaneously, but thermoeffector activation can also occur as a result of peripheral cooling alone. The responses to cold, and the hazards associated with cold exposure, are moderated by factors which influence heat production and heat loss, including the severity and duration of cold stimuli, accompanying exercise, the magnitude of the metabolic response, and individual characteristics such as body composition, age, and gender. Cold stress can quickly overwhelm human thermoregulation with consequences ranging from impaired performance to death. This review provides a comprehensive overview of the human physiological responses to acute cold exposure. C1 Univ Wollongong, Dept Biomed Sci, Wollongong, NSW 2522, Australia. Univ Portsmouth, Inst Biomed & Biomol Sci, Portsmouth, Hants, England. NASA, Ames Res Ctr, Lab Human Environm Physiol, Moffett Field, CA 94035 USA. RP Taylor, NAS (reprint author), Univ Wollongong, Dept Biomed Sci, Northfields Ave, Wollongong, NSW 2522, Australia. EM nigel_taylor@uow.edu.au RI Taylor, Nigel/A-1975-2014 NR 187 TC 98 Z9 109 U1 28 U2 99 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD MAY PY 2004 VL 75 IS 5 BP 444 EP 457 PG 14 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 816JY UT WOS:000221107400011 PM 15152898 ER PT J AU Bloom, JD Wilke, CO Arnold, FH Adami, C AF Bloom, JD Wilke, CO Arnold, FH Adami, C TI Stability and the evolvability of function in a model protein SO BIOPHYSICAL JOURNAL LA English DT Article ID SEQUENCE SPACE; EVOLUTIONARY LANDSCAPES; DIRECTED EVOLUTION; PERSPECTIVE; PRINCIPLES; TOPOLOGY; MUTATION AB Functional proteins must fold with some minimal stability to a structure that can perform a biochemical task. Here we use a simple model to investigate the relationship between the stability requirement and the capacity of a protein to evolve the function of binding to a ligand. Although our model contains no built-in tradeoff between stability and function, proteins evolved function more efficiently when the stability requirement was relaxed. Proteins with both high stability and high function evolved more efficiently when the stability requirement was gradually increased than when there was constant selection for high stability. These results show that in our model, the evolution of function is enhanced by allowing proteins to explore sequences corresponding to marginally stable structures, and that it is easier to improve stability while maintaining high function than to improve function while maintaining high stability. Our model also demonstrates that even in the absence of a fundamental biophysical tradeoff between stability and function, the speed with which function can evolve is limited by the stability requirement imposed on the protein. C1 CALTECH, Dept Chem, Pasadena, CA 91125 USA. CALTECH, Digital Life Lab, Pasadena, CA 91125 USA. CALTECH, Div Chem & Chem Engn, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Bloom, JD (reprint author), CALTECH, Dept Chem, 210-41, Pasadena, CA 91125 USA. EM bloom@caltech.edu RI Adami, Christoph/A-5181-2009; Adami, Christoph/A-9675-2011; Wilke, Claus/B-4643-2008; Bloom, Jesse/C-6837-2013 OI Adami, Christoph/0000-0002-2915-9504; Wilke, Claus/0000-0002-7470-9261; Bloom, Jesse/0000-0003-1267-3408 NR 37 TC 52 Z9 53 U1 0 U2 8 PU CELL PRESS PI CAMBRIDGE PA 600 TECHNOLOGY SQUARE, 5TH FLOOR, CAMBRIDGE, MA 02139 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD MAY PY 2004 VL 86 IS 5 BP 2758 EP 2764 DI 10.1016/S0006-3495(04)74329-5 PG 7 WC Biophysics SC Biophysics GA 816HW UT WOS:000221102000011 PM 15111394 ER PT J AU Kitchell, JF Kaplan, IC Cox, SP Martell, SJD Essington, TE Boggs, CH Walters, CJ AF Kitchell, JF Kaplan, IC Cox, SP Martell, SJD Essington, TE Boggs, CH Walters, CJ TI Ecological and economic components of alternative fishing methods to reduce by-catch of marlin in a tropical pelagic ecosystem SO BULLETIN OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Symposium in Fisheries Ecology CY NOV 05-07, 2002 CL Mote Marine Lab, Sarasota, FL SP William R & Lenore Mote Endowment, Florida State Univ HO Mote Marine Lab ID CENTRAL PACIFIC-OCEAN; FISHERIES MANAGEMENT; DYNAMICS; TUNAS AB Recently, the U.S. National Marine Fisheries Service was petitioned to list North Atlantic white marlin as an endangered species under the Endangered Species Act (ESA). The ESA requires a stock assessment of status and trends for listed species and will severely restrict U.S. commercial and recreational fisheries, but because by-catch by foreign longline fleets account for more than 95% of marlin mortality, applying the ESA to U.S. fleets would have little direct effect. We analyzed an alternative management policy by using an Ecosim model of the central north Pacific to simulate a fishing strategy that reduces marlin by-catch by removing longline hooks that fish in water less than 120 m in depth. Mortality rates might be reduced by about 50% through removal of less than 15% of hooks. After 30 yrs, blue marlin biomass had increased to 2.8 times, and striped marlin biomass to about 1.8 times, that expected under no change in fishing practices. Ecological consequences included decreased abundance of adult yellowfin tuna. This result produced an economic trade-off of lost fishery revenues (primarily yellowfin tuna) and gains due to increased catches of billfishes in recreational fisheries. C1 Univ Wisconsin, Ctr Limnol, Madison, WI 53706 USA. Simon Fraser Univ, Sch Resource & Environm Management, Burnaby, BC V5A 1S6, Canada. SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu, HI 96822 USA. Univ British Columbia, Fisheries Ctr, Vancouver, BC V6T 1Z4, Canada. RP Kitchell, JF (reprint author), Univ Wisconsin, Ctr Limnol, Madison, WI 53706 USA. RI Walters, Carl/D-5714-2012; Cox, Sean/I-5374-2012 NR 41 TC 12 Z9 13 U1 0 U2 12 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD MAY PY 2004 VL 74 IS 3 BP 607 EP 619 PG 13 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 845ZG UT WOS:000223283600009 ER PT J AU Shah, AS Bressler, SL Knuth, KH Ding, MZ Mehta, AD Ulbert, I Schroeder, CE AF Shah, AS Bressler, SL Knuth, KH Ding, MZ Mehta, AD Ulbert, I Schroeder, CE TI Neural dynamics and the fundamental mechanisms of event-related brain potentials SO CEREBRAL CORTEX LA English DT Article DE current source density (CSD); evoked response; phase resetting; oscillatory activity; single-trial analyses; synchronization ID INTERMODAL SELECTIVE ATTENTION; RECORDED FLASH-VEP; EVOKED-POTENTIALS; AWAKE MACAQUE; NEURONAL SYNCHRONIZATION; MONKEY; EEG; RESPONSES; CORTEX; MODULATION AB Event-related potentials (ERPs) provide a critical link between the hemodynamic response, as measured by functional magnetic resonance imaging, and the dynamics of the underlying neuronal activity. Single-trial ERP recordings capture the oscillatory activity that are hypothesized to underlie both communication between brain regions and amplified processing of behaviorally relevant stimuli. However, precise interpretations of ERPs are precluded by uncertainty about their neural mechanisms. One influential theory holds that averaged sensory ERPs are generated by partial phase resetting of ongoing electroencephalographic oscillations, while another states that ERPs result from stimulus-evoked neural responses. We formulated critical predictions of each theory and tested these using direct, intracortical analyses of neural activity in monkeys. Our findings support a predominant role for stimulus-evoked activity in sensory ERP generation, and they outline both logic and methodology necessary for differentiating evoked and phase resetting contributions to cognitive and motor ERPs in future studies. C1 Albert Einstein Coll Med, Dept Neurosci, Bronx, NY 10461 USA. Nathan S Kline Inst Psychiat Res, Cognit Neurosci & Schizophrenia Program, Orangeburg, NY 10962 USA. Florida Atlantic Univ, Ctr Complex Syst & Brain Sci, Boca Raton, FL 33431 USA. NASA, Computat Sci Div, Ames Res Ctr, Moffett Field, CA 94035 USA. Cornell Univ, Weill Med Coll, Dept Neurol Surg, New York, NY 10021 USA. Hungarian Acad Sci, Inst Psychol, H-1394 Budapest, Hungary. RP Schroeder, CE (reprint author), 140 Old Orangeburg Rd, Orangeburg, NY 10962 USA. EM schrod@nki.rmh.org RI Ulbert, Istvan/F-2213-2010 FU NIMH NIH HHS [MH64204, MH60358]; PHS HHS [T32M07288] NR 32 TC 154 Z9 156 U1 2 U2 14 PU OXFORD UNIV PRESS INC PI CARY PA JOURNALS DEPT, 2001 EVANS RD, CARY, NC 27513 USA SN 1047-3211 J9 CEREB CORTEX JI Cereb. Cortex PD MAY PY 2004 VL 14 IS 5 BP 476 EP 483 DI 10.1093/cercor/bhh009 PG 8 WC Neurosciences SC Neurosciences & Neurology GA 813GL UT WOS:000220895500002 PM 15054063 ER PT J AU Meyer, H Zhong, F AF Meyer, H Zhong, F TI Equilibration and other dynamic properties of fluids near the liquid-vapor critical point SO COMPTES RENDUS MECANIQUE LA English DT Article DE fluid mechanics; supercritical fluid; equilibration; piston effect; microgravity; Rayleigh-Benard configuration; convection numerical simulation ID SPACELAB MISSION D-2; NEAR-CRITICAL FLUID; THAN-T-C; PURE FLUID; DENSITY EQUILIBRATION; THERMAL RESPONSE; HEAT-TRANSPORT; GRAVITY; MICROGRAVITY; HE-3 AB A review is presented on the advances in understanding equilibration phenomena in compressible pure fluids near the liquid-vapor critical point. The important role of the piston effect is stressed. The equilibration of temperature and density of a fluid sample, kept in a constant volume, are described. Examples are given both above and below the critical point under Earth's gravity (I g) and microgravity conditions. The good agreement between experimental results and simulations demonstrate the present understanding of the process. The convection onset of a compressible pure fluid in a Rayleigh-Benard cell at I g is described. The impact of the piston effect on the transient, which leads to damped oscillations on the way to reaching a steady state convection, is also described. Here again the results of experiments and numerical simulations are compared. (C) 2004 Academie des sciences. Published by Elsevier SAS. All rights reserved. C1 Duke Univ, Dept Phys, Durham, NC 27708 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Meyer, H (reprint author), Duke Univ, Dept Phys, Durham, NC 27708 USA. EM hm@phy.duke.edu NR 39 TC 4 Z9 4 U1 0 U2 3 PU EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS PA 23 RUE LINOIS, 75724 PARIS, FRANCE SN 1631-0721 J9 CR MECANIQUE JI C. R. Mec. PD MAY-JUN PY 2004 VL 332 IS 5-6 BP 327 EP 343 DI 10.1016/j.crme.2004.02.006 PG 17 WC Mechanics SC Mechanics GA 828FJ UT WOS:000221958900002 ER PT J AU Muller, SD Mezic, I Walther, JH Koumoutsakos, P AF Muller, SD Mezic, I Walther, JH Koumoutsakos, P TI Transverse momentum micromixer optimization with evolution strategies SO COMPUTERS & FLUIDS LA English DT Article AB We conduct a numerical study of mixing in a transverse momentum micromixer. Good values for actuation frequencies can be determined using simple kinematic arguments, and evolution strategies are introduced for the optimization of mixing by adjusting the control parameters in micromixer devices. It is shown that the chosen optimization algorithm can identify, in an automated fashion, effective actuation parameters. We find that optimal frequencies for increasing number of transverse channels are superposable despite the non-linear nature of the mixing process. (C) 2003 Elsevier Ltd. All rights reserved. C1 ETH, Swiss Fed Inst Technol, Inst Computat Sci, CH-8092 Zurich, Switzerland. Univ Calif Santa Barbara, Dept Mech & Environm Engn, Santa Barbara, CA 93106 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Muller, SD (reprint author), ETH, Swiss Fed Inst Technol, Inst Computat Sci, CH-8092 Zurich, Switzerland. RI Koumoutsakos, Petros/A-2846-2008; Walther, Jens/D-9549-2015 OI Koumoutsakos, Petros/0000-0001-8337-2122; Walther, Jens/0000-0001-8100-9178 NR 21 TC 11 Z9 12 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PD MAY PY 2004 VL 33 IS 4 BP 521 EP 531 DI 10.1016/j.compfluid.2003.07.004 PG 11 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA 759LJ UT WOS:000187738900002 ER PT J AU Dagg, M Benner, R Lohrenz, S Lawrence, D AF Dagg, M Benner, R Lohrenz, S Lawrence, D TI Transformation of dissolved and particulate materials on continental shelves influenced by large rivers: plume processes SO CONTINENTAL SHELF RESEARCH LA English DT Review ID GULF-OF-MEXICO; NORTH-ATLANTIC OCEAN; ENHANCED PRIMARY PRODUCTION; TERRESTRIAL ORGANIC-MATTER; NW MEDITERRANEAN-SEA; MISSISSIPPI RIVER; AMAZON RIVER; COASTAL WATERS; PHYTOPLANKTON PRODUCTION; COMMUNITY STRUCTURE AB The world's ten largest rivers transport approximately 40% of the fresh water and particulate materials entering the ocean. The impact of large rivers is important on a regional/continental scale (e.g. the Mississippi drains similar to40% of the conterminous US and carries approximately 65% of all the suspended solids and dissolved solutes that enter the ocean from the US) and on a global scale (e.g. the Amazon River annually supplies approximately 20% of all the freshwater that enters the ocean; e.g. approximately 85% of all sedimenting organic carbon in the ocean accumulates in coastal margin regions). River plume processes are affected by a suite of complex factors that are not fully understood. It is clear however, that the composition, concentration and delivery of terrestrial materials by large rivers cannot be understood by simply scaling Lip the magnitudes and impacts of dominant processes in smaller rivers. Because of high rates of particulate and water discharge, the estuarine processes associated with major rivers usually take place on the adjacent continental shelf instead of in a physically confined estuary. This influences the magnitude and selectivity of processes that transform, retain or export terrestrial materials. Buoyancy is a key mediating factor in transformation processes in the coastal margin. In this paper we review and synthesize Current understanding of the transformation processes of dissolved and particulate organic and inorganic materials associated with large river (buoyant) plumes. Chemical and biological activities are greatly enhanced by the changed physical and optical environment within buoyant plumes. Time and space scales over which these transformation processes occur vary greatly, depending on factors such as scales of discharge, suspended sediment loads. light and temperature. An adequate understanding of transformation processes in these highly dynamic, buoyancy-driven systems is lacking. In this paper, we review the biogeochemical processes that occur in large river plumes. (C) 2004 Elsevier Ltd. All rights reserved. C1 Louisiana Univ Marine Consortium, Chauvin, LA 70344 USA. Univ S Carolina, Marine Sci Program, Dept Biol Sci, Columbia, SC 29208 USA. Univ So Mississippi, Stennis Space Ctr, Dept Marine Sci, Stennis Space Ctr, MS 39529 USA. RP Dagg, M (reprint author), Louisiana Univ Marine Consortium, 8124 Highway 56, Chauvin, LA 70344 USA. EM mdaag@lumcon.edu RI Benner, Ronald/M-4412-2015; OI Benner, Ronald/0000-0002-1238-2777; Lohrenz, Steven/0000-0003-3811-2975 NR 160 TC 220 Z9 233 U1 10 U2 59 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0278-4343 J9 CONT SHELF RES JI Cont. Shelf Res. PD MAY PY 2004 VL 24 IS 7-8 BP 833 EP 858 DI 10.1016/j.csr.2004.02.003 PG 26 WC Oceanography SC Oceanography GA 828CF UT WOS:000221949600006 ER PT J AU Nesterov, VV Antipin, MY Nesterov, VN Penn, BG Frazier, DO Timofeeva, TV AF Nesterov, VV Antipin, MY Nesterov, VN Penn, BG Frazier, DO Timofeeva, TV TI Thermally stable Imines as new potential nonlinear optical materials SO CRYSTAL GROWTH & DESIGN LA English DT Article ID PERFECT POLAR ALIGNMENT; CRYSTAL-STRUCTURES; CHROMOPHORES; DIAMINOMALEONITRILE; CHEMISTRY; DESIGN; SALTS; POLYMORPHISM; DERIVATIVES; STABILITY AB In the search for new thermostable acentric nonlinear optical (NLO) crystalline materials, several polar imine derivatives with the general structure D-pi-A(D') were synthesized and studied. Introduction of the amino group (D') into the acceptor moiety of these molecules was supposed to bring hydrogen bonds into the crystal structures, and so to elevate their melting points and to assist acentric molecular packings. Ten compounds of this type have been prepared, and for six of them single crystals have been grown and characterized by X-ray diffraction analysis. High melting points were found for all synthesized compounds. It was found that four compounds have acentric crystal structures. Analysis of the crystal packing and hydrogen bonding in the compounds studied has been carried out along with quantum calculations of the molecular NLO responses. This allowed an understanding of the thermal stability of the compounds studied and some of their NLO characteristics. C1 New Mexico Highlands Univ, Dept Nat Sci, Las Vegas, NM 87701 USA. Russian Acad Sci, Inst Organoelement Cpds, Moscow, Russia. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Timofeeva, TV (reprint author), New Mexico Highlands Univ, Dept Nat Sci, Las Vegas, NM 87701 USA. EM tvtimofeeva@nmhu.edu NR 41 TC 17 Z9 17 U1 2 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1528-7483 J9 CRYST GROWTH DES JI Cryst. Growth Des. PD MAY-JUN PY 2004 VL 4 IS 3 BP 521 EP 531 DI 10.1021/cg034068c PG 11 WC Chemistry, Multidisciplinary; Crystallography; Materials Science, Multidisciplinary SC Chemistry; Crystallography; Materials Science GA 818TM UT WOS:000221267400019 ER PT J AU Tuszynski, MH Stokols, S Sakamoto, J Weiss, J AF Tuszynski, MH Stokols, S Sakamoto, J Weiss, J TI Nerve guidance channels orient and guide axon growth after spinal cord injury. SO EXPERIMENTAL NEUROLOGY LA English DT Meeting Abstract CT 11th Annual Conference of the American-Society-for-Neural-Transplantation-and-Repair CY MAY 06-09, 2004 CL Clearwater, FL SP Amer Soc Neural Transplantat & Repair C1 UCSD, Dept Neurosci, La Jolla, CA USA. Jet Prop Labs, Pasadena, CA USA. NR 0 TC 1 Z9 1 U1 1 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0014-4886 J9 EXP NEUROL JI Exp. Neurol. PD MAY PY 2004 VL 187 IS 1 BP 221 EP 221 PG 1 WC Neurosciences SC Neurosciences & Neurology GA 813FE UT WOS:000220892200091 ER PT J AU Hotinski, RM Kump, LR Arthur, MA AF Hotinski, RM Kump, LR Arthur, MA TI The effectiveness of the Paleoproterozoic biological pump: A delta C-13 gradient from platform carbonates of the Pethei Group (Great Slave Lake Supergroup, NWT) SO GEOLOGICAL SOCIETY OF AMERICA BULLETIN LA English DT Article DE Precambrian; carbon cycle; isotope ratios; productivity; marine ID OXYGEN ISOTOPIC COMPOSITION; PROTEROZOIC FORELAND BASIN; ORGANIC-CARBON; TRACE-ELEMENT; FRACTIONATION; GEOCHEMISTRY; SEAWATER; CANADA; OCEANS; PHOTOSYNTHESIS AB Samples of carbonate cements collected along a depth transect of the Pethei Platform, a 1.9 Ga stromatolitic reef, reveal a small (similar to0.5parts per thousand) carbon isotope gradient between shallow and basinal facies. The magnitude of this gradient would conventionally be interpreted as indicating low export of organic matter from ocean surface waters, but steady-state simulations using a two-box model of the Paleoproterozoic ocean suggest that the small carbon isotope gradient could instead be due to high partial pressures of carbon dioxide in the Paleoproterozoic atmosphere, which would increase the ocean's dissolved inorganic carbon content and damp the effects of biological pumping. If the Paleoproterozoic atmosphere were indeed enriched in atmospheric CO2 in compensation for a less luminous Sun, these results indicate that the planktonic biota was a significant component of the Precambrian global carbon and nutrient cycles, affecting if not regulating (as today) the composition of both surface and deep ocean waters. C1 Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. Penn State Univ, NASA, Astrobiol Inst, University Pk, PA 16802 USA. RP Penn State Univ, Dept Geosci, Univ Pk, University Pk, PA 16802 USA. EM lkump@psu.edu RI Kump, Lee/H-8287-2012; Arthur, Michael/E-2872-2014 OI Arthur, Michael/0000-0002-3028-6279 NR 67 TC 22 Z9 22 U1 1 U2 7 PU GEOLOGICAL SOC AMER, INC PI BOULDER PA PO BOX 9140, BOULDER, CO 80301-9140 USA SN 0016-7606 EI 1943-2674 J9 GEOL SOC AM BULL JI Geol. Soc. Am. Bull. PD MAY-JUN PY 2004 VL 116 IS 5-6 BP 539 EP 554 DI 10.1130/B25272.1 PG 16 WC Geosciences, Multidisciplinary SC Geology GA 815MH UT WOS:000221045900003 ER PT J AU Potter, C Klooster, S Steinbach, M Tan, PN Kumar, V Shekhar, S De Carvalho, CR AF Potter, C Klooster, S Steinbach, M Tan, PN Kumar, V Shekhar, S De Carvalho, CR TI Understanding global teleconnections of climate to regional model estimates of Amazon ecosystem carbon fluxes SO GLOBAL CHANGE BIOLOGY LA English DT Article DE carbon flux; ecosystem model; global climate; remote sensing ID SURFACE TEMPERATURE ANOMALIES; NORTH-ATLANTIC OSCILLATION; NINO-SOUTHERN-OSCILLATION; NET PRIMARY PRODUCTION; INTERANNUAL VARIABILITY; TERRESTRIAL ECOSYSTEMS; SATELLITE; ENSO; PRECIPITATION; EXCHANGE AB We have investigated global teleconnections of climate to regional satellite-driven observations for prediction of Amazon ecosystem production, in the form of monthly estimates of net carbon exchange over the period 1982-1998 from the NASA-CASA (Carnegie-Ames-Stanford) biosphere model. This model is driven by observed surface climate and monthly estimates of vegetation leaf area index (LAI) and fraction of absorbed PAR (fraction of photosynthetically active radiation, FPAR) generated from the NOAA satellite advanced very high-resolution radiometer (AVHRR) and similar sensors. Land surface AVHRR data processing using modified moderate-resolution imaging spectroradiometer radiative transfer algorithms includes improved calibration for intra- and intersensor variations, partial atmospheric correction for gaseous absorption and scattering, and correction for stratospheric aerosol effects associated with volcanic eruptions. Results from our analysis suggest that anomalies of net primary production and net ecosystem production predicted from the NASA-CASA model over large areas of the Amazon region east of 60degreesW longitude are strongly correlated with the Southern Oscillation index. Extensive areas of the south-central Amazon show strong linkages of the FPAR and the NASA-CASA anomaly record to the Arctic Oscillation index, which help confirm a strong relation to southern Atlantic climate anomalies, with associated impacts on Amazon rainfall patterns. Processes are investigated for these teleconnections of global climate to Amazon ecosystem carbon fluxes and regional land surface climate. C1 NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Moffett Field, CA 94035 USA. Calif State Univ Monterey Bay, Seaside, CA USA. Univ Minnesota, Minneapolis, MN USA. Embrapa Amazonia Oriental, Belem, Para, Brazil. RP Potter, C (reprint author), NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Mail Stop 424-4, Moffett Field, CA 94035 USA. EM cpotter@mail.arc.nasa.gov NR 44 TC 21 Z9 23 U1 0 U2 8 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 1354-1013 J9 GLOBAL CHANGE BIOL JI Glob. Change Biol. PD MAY PY 2004 VL 10 IS 5 BP 693 EP 703 DI 10.1111/j.1529-8817.2003.00752.x PG 11 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 820WY UT WOS:000221421600012 ER PT J AU Turtle, EP Keszthelyi, LP McEwen, AS Radebaugh, J Milazzo, M Simonelli, DP Geissler, P Williams, DA Perry, J Jaeger, WL Klaasen, KP Breneman, HH Denk, T Phillips, CB AF Turtle, EP Keszthelyi, LP McEwen, AS Radebaugh, J Milazzo, M Simonelli, DP Geissler, P Williams, DA Perry, J Jaeger, WL Klaasen, KP Breneman, HH Denk, T Phillips, CB CA Galileo SSI Team TI The final Galileo SSI observations of Io: orbits G28-I33 SO ICARUS LA English DT Article DE Io; surfaces; satellite; satellites of Jupiter; volcanism; tectonics; geological processes ID JUPITERS MOON IO; ACTIVE VOLCANISM; FLOW EMPLACEMENT; SULFUR FLOWS; MOUNTAINS; ERUPTION; CALIBRATION; MISSION; SYSTEM; PLUMES AB We present the observations of to acquired by the Solid State Imaging (SSI) experiment during the Galileo Millennium Mission (GMM) and the strategy we used to plan the exploration of to. Despite Galileo's tight restrictions on data volume and downlink capability and several spacecraft and camera anomalies due to the intense radiation. close to Jupiter, there were many successful SSI observations during GMM. Four giant, high-latitude plumes, including the largest plume ever observed on to, were documented over a period of eight months; only faint evidence of such plumes had been seen since the Voyager 2 encounter, despite monitoring by Galileo during the previous five years. Moreover, the source of one of the plumes was Tvashtar Catena, demonstrating that a single site can exhibit remarkably diverse eruption styles-from a curtain of lava fountains, to extensive surface flows, and finally a similar to 400 km high plume-over a relatively short period of time (similar to 13 months between orbits 125 and G29). Despite this substantial activity, no evidence of any truly new volcanic center was seen during the six years of Galileo observations. The recent observations also revealed details of mass wasting processes acting on to. Slumping and landsliding dominate and occur in close proximity to each other, demonstrating spatial variation in material properties over distances of several kilometers. However, despite the ubiquitous evidence for mass wasting, the rate of volcanic resurfacing seems to dominate; the floors of paterae in proximity to mountains are generally free of debris. Finally, the highest resolution observations obtained during Galileo's final encounters with to provided further evidence for a wide diversity of surface processes at work on to. (C) 2003 Elsevier Inc. All rights reserved. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Planetary Sci Inst, Tucson, AZ 85719 USA. US Geol Survey, Astrogeol Program, Flagstaff, AZ 86001 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. DLR, D-12489 Berlin, Germany. SETI Inst, Mountain View, CA 94043 USA. RP Turtle, EP (reprint author), Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. EM turtle@lpl.arizona.edu RI Turtle, Elizabeth/K-8673-2012 OI Turtle, Elizabeth/0000-0003-1423-5751 NR 60 TC 36 Z9 36 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 J9 ICARUS JI Icarus PD MAY PY 2004 VL 169 IS 1 BP 3 EP 28 DI 10.1016/j.icarus.2003.10.014 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 817MA UT WOS:000221180400002 ER PT J AU Radebaugh, J McEwen, AS Milazzo, MP Keszthelyi, LP Davies, AG Turtle, EP Dawson, DD AF Radebaugh, J McEwen, AS Milazzo, MP Keszthelyi, LP Davies, AG Turtle, EP Dawson, DD TI Observations and temperatures of Io's Pele Patera from Cassini and Galilee spacecraft images SO ICARUS LA English DT Article DE satellites of Jupiter; Io; volcanism; surfaces-satellite; interiors ID JUPITERS MOON IO; THERMAL EMISSION; SILICATE VOLCANISM; ACTIVE VOLCANISM; HOT-SPOTS; LAVA LAKE; ERUPTION; PLUME; MISSION; LITHOSPHERE AB Pele has been the most intense high-temperature hotspot on Io to be continuously active during the Galileo monitoring from 1996-2001. A suite of characteristics suggests that Pele is an active lava lake inside a volcanic depression. In 2000-2001, Pele was observed by two spacecraft, Cassini and Galileo. The Cassini observations revealed that Pele is variable in activity over timescales of minutes, typical of active lava lakes in Hawaii and Ethiopia. These observations also revealed that the short-wavelength thermal emission from Pele decreases with rotation of Io by a factor significantly greater than the cosine of the emission angle, and that the color temperature becomes more variable and hotter at high emission angles. This behavior suggests that a significant portion of the visible thermal emission from Pele comes from lava fountains within a topographically confined lava body. High spatial resolution, nightside images from a Galileo flyby in October 2001 revealed a large, relatively cool (< 800 K) region, ringed by bright hotspots, and a central region of high thermal emission, which is hypothesized to be due to fountaining and convection in the lava lake. Images taken through different filters revealed color temperatures of 1500 +/- 80 K from Cassini ISS data and 1605 +/- 220 and 14120 +/- 100 K from small portions of Galileo SSI data. Such temperatures are near the upper limit for basaltic compositions. Given the limitations of deriving lava eruption temperature in the absence of in situ measurement, it is possible that Pele has lavas with ultramafic compositions. The long-lived, vigorous activity of what is most likely an actively overturning lava lake in Pele Patera indicates that there is a strong connection to a large, stable magma source region. (C) 2003 Elsevier Inc. All rights reserved. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. US Geol Survey, Flagstaff, AZ 86001 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Radebaugh, J (reprint author), Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. EM jani@lpl.arizona.edu RI Turtle, Elizabeth/K-8673-2012 OI Turtle, Elizabeth/0000-0003-1423-5751 NR 60 TC 36 Z9 36 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 EI 1090-2643 J9 ICARUS JI Icarus PD MAY PY 2004 VL 169 IS 1 BP 65 EP 79 DI 10.1016/j.icarus.2003.10.019 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 817MA UT WOS:000221180400004 ER PT J AU Williams, DA Schenk, PM Moore, JM Keszthelyi, LP Turtle, EP Jaeger, WL Radebaugh, J Milazzo, MP Lopes, RMC Greeley, R AF Williams, DA Schenk, PM Moore, JM Keszthelyi, LP Turtle, EP Jaeger, WL Radebaugh, J Milazzo, MP Lopes, RMC Greeley, R TI Mapping of the Culann-Tohil region of Io from Galileo imaging data SO ICARUS LA English DT Article DE satellites of Jupiter; Io; geological processes; volcanism; surfaces (satellite) ID JUPITERS MOON IO; ACTIVE VOLCANISM; SATELLITE IO; SULFUR; MOUNTAINS; SURFACE; SPECTROMETER; PROMETHEUS; IRRADIATION; SCIENCE AB We have used Galileo spacecraft data to produce a geomorphologic map of the Culann-Tohil region of Io's antijovian hemisphere. This region includes a newly discovered shield volcano, Tsui Goab Tholus and a neighboring bright flow field, Tsui Goab Fluctus, the active Culann Patera and the enigmatic Tohil Mons-Radegast Patera-Tohil Patera complex. Analysis of Voyager global color and Galileo Solid-State Imaging (SSI) high-resolution, regional (50-330 m/pixel), and global color (1.4 km/pixel) images, along with available Galileo Near-Infrared Mapping Spectrometer (NIMS) data, suggests that 16 distinct geologic units can be defined and characterized in this region, including 5 types of diffuse deposits. Tsui Goab Fluctus is the center of a low-temperature hotspot detected by NIMS late during the Galileo mission, and could represent the best case for active effusive sulfur volcanism detected by Galileo. The Culann volcanic center has produced a range of explosive and effusive deposits, including an outer yellowish ring of enhanced sulfur dioxide (SO2), an inner red ring of SO2 with shortchain sulfur (S-3-S-4) contaminants, and two irregular green diffuse deposits (one in Tohil Patera) apparently produced by the interaction of dark, silicate lava flows with sulfurous contaminants ballistically-emplaced from Culann's eruption plume(s). Fresh and red-mantled dark lava flows west of the Culann vent can be contrasted with unusual red-brown flows east of the vent. These red-brown flows have a distinct color that is suggestive of a compositional difference, although whether this is due to surface alteration or distinct lava compositions cannot be determined. The main massif of Tohil Mons is covered with ridges and grooves, defining a unit of tectonically disrupted crustal materials. Tohil Mons also contains a younger unit of mottled crustal materials that were displaced by mass wasting processes. Neighboring Radegast Patera contains a NIMS hotspot and a young lava lake of dark silicate flows, whereas the southwest portion of Tohil Patera contains white flow-like units, perhaps consisting of 'ponds' of effusively emplaced SO2. From 0degrees-15degrees S the hummocky bright plains unit away from volcanic centers contains scarps, grooves, pits, graben, and channel-like features, some of which have been modified by erosion. Although the most active volcanic centers appear to be found in structural lows (as indicated by mapping of scarps), DEMs derived from stereo images show that, with the exception of Tohil Mons, there is less than 1 km of relief in the Culann-Tohil region. There is no discernable correlation between centers of active volcanism and topography. (C) 2003 Elsevier Inc. All rights reserved. C1 Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. Lunar & Planetary Inst, CASS, USRA, Houston, TX 77058 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. US Geol Survey, Astrogeol Team, Flagstaff, AZ 86001 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Inst Planetary Sci, Tucson, AZ USA. CALTECH, NASA, Jet Prop Lab, Pasadena, CA 91109 USA. RP Williams, DA (reprint author), Arizona State Univ, Dept Geol Sci, Bateman Phys Sci Bldg,F506B, Tempe, AZ 85287 USA. EM david.williams@asu.edu RI Turtle, Elizabeth/K-8673-2012; Lopes, Rosaly/D-1608-2016 OI Turtle, Elizabeth/0000-0003-1423-5751; Lopes, Rosaly/0000-0002-7928-3167 NR 69 TC 23 Z9 23 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2004 VL 169 IS 1 BP 80 EP 97 DI 10.1016/j.icarus.2003.08.024 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 817MA UT WOS:000221180400005 ER PT J AU Schenk, PM Wilson, RR Davies, AG AF Schenk, PM Wilson, RR Davies, AG TI Shield volcano topography and the rheology of lava flows on Io SO ICARUS LA English DT Article DE Io; volcanism; topography; stereo ID JUPITERS MOON IO; SULFUR FLOWS; RA PATERA; GALILEO; ERUPTION; EMPLACEMENT; CONSTRAINTS; SATELLITES; MOUNTAINS; VOYAGER AB Stereo and photoclinometry derived topography of shield-like volcanoes on Io indicate little relief (< 3 km) and very low slopes (0.2degrees to 0.6degrees). Several shield volcanoes appear to be associated with broad rises of 1 to 3 km, but only 5 shield volcanoes have been identified with steep flank slopes (between 4degrees and 10degrees). These steep slopes are restricted to within 20-30 km of the summit, but where discernable, most of the lava flows observed on these edifices occur on the outer flanks where slopes are less than a degree. Despite their abundance, ionian shield volcanoes are among the flattest in the Solar System. The steepest volcanoes on Io are most comparable to large venusian shield volcanoes. Using simplistic Bingham rheologies we estimate the viscosity and yield strengths of ionian lavas. Yield strengths are estimated at 10(1)-10(2) Pa, lower than most basaltic lavas. Viscosity estimates range from 10(3) to 10(5) Pas, although these are probably upper limits. Actual values may have been as low as 10(0) Pa s. Viscosity is sensitive to flow velocity, which is poorly known on Io. The best constraint on flow velocity comes from observations of the 1997 Pillan eruption, which bracket the eruptive phase to 132 day maximum, and more probably less than 50 days. Low slopes, long run-out distances and our estimated rheologic properties are consistent with (but not proof of) a low silica, low viscosity, high temperature composition for ionian lavas, supporting arguments for low-silica lava compositions such as basalt or komatiite. We cannot eliminate sulfur on rheologic grounds, however. (C) 2004 Elsevier Inc. All rights reserved. C1 Lunar & Planetary Inst, Houston, TX 77058 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Schenk, PM (reprint author), Lunar & Planetary Inst, 3600 Bay Area Blvd, Houston, TX 77058 USA. EM schenk@lpi.usra.edu NR 39 TC 27 Z9 27 U1 1 U2 4 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 MAY PY 2004 VL 169 IS 1 BP 98 EP 110 DI 10.1016/j.icarus.2004.01.015 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 817MA UT WOS:000221180400006 ER PT J AU Rathbun, JA Spencer, JR Tamppari, LK Martin, TZ Barnard, L Travis, LD AF Rathbun, JA Spencer, JR Tamppari, LK Martin, TZ Barnard, L Travis, LD TI Mapping of Io's thermal radiation by the Galileo photopolarimeter-radiometer (PPR) instrument SO ICARUS LA English DT Article DE Io; volcanism; infrared observations; surfaces; satellites; thermal histories ID ACTIVE VOLCANISM; PELE PLUME; HEAT-FLOW; EMISSION AB Between 1999 and 2002, the Galileo spacecraft made 6, close flybys of to during which many observations of Io's thermal radiation were made with the photopolarimeter-radiometer (PPR). While the NIMS instrument could measure thermal emission from hot spots with T > 200 K, PPR was the only Galileo instrument capable of mapping the lower temperatures of older, cooling lava flows, and the passive background. We tabulate all data taken by PPR of Io during these flybys and describe some scientific highlights revealed by the data. The data include almost complete coverage of Io at better than 250 km resolution, with extensive regional coverage at higher resolutions. We found a modest poleward drop in nighttime background temperatures and evidence of thermal inertia variations across the surface. Comparison of high spatial resolution temperature measurements with observed daytime SO2 gas pressures on Io provides evidence for local cold trapping of SO2 frost on scales smaller than the 60 km resolution of the PPR data. We also calculated the power output from several hot spots and estimated total global heat flow to be about 2.0-2.6 W m(-2). The low-latitude diurnal temperature variations for the regions between obvious hot spots are well matched by a laterally-inhomogeneous thermal model with less than 1 W m(-2) endogenic heat flow. (C) 2004 Elsevier Inc. All rights reserved. C1 Univ Redlands, Redlands, CA 92373 USA. Lowell Observ, Flagstaff, AZ 86001 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Raytheon Co, Pasadena, CA 91109 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Rathbun, JA (reprint author), Univ Redlands, 1200 E Colton Ave,POB 3080, Redlands, CA 92373 USA. EM julie_rathbun@redlands.edu NR 31 TC 58 Z9 58 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2004 VL 169 IS 1 BP 127 EP 139 DI 10.1016/j.icarus.2003.12.021 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 817MA UT WOS:000221180400008 ER PT J AU Lopes, RMC Kamp, LW Smythe, WD Mouginis-Mark, P Kargel, J Radebaugh, J Turtle, EP Perry, J Williams, DA Carlson, RW Doute, S AF Lopes, RMC Kamp, LW Smythe, WD Mouginis-Mark, P Kargel, J Radebaugh, J Turtle, EP Perry, J Williams, DA Carlson, RW Doute, S CA Galileo NIMS & SSI Teams TI Lava lakes on Io: observations of Io's volcanic activity from Galileo NIMS during the 2001 fly-bys SO ICARUS LA English DT Article DE Io; volcanism; satellites of Jupiter ID INFRARED MAPPING SPECTROMETER; JUPITERS MOON IO; TEMPERATURE-MEASUREMENTS; SILICATE VOLCANISM; THERMAL EMISSION; FLOW EMPLACEMENT; HOT-SPOTS; SULFUR; ERUPTION; PROMETHEUS AB Galileo's Near-Infrared Mapping Spectrometer (NIMS) obtained its final observations of Io during the spacecraft's fly-bys in August (131) and October 2001 (132). We present a summary of the observations and results from these last two fly-bys, focusing on the distribution of thermal emission from Io's many volcanic regions that give insights into the eruption styles of individual hot spots. We include a compilation of hot spot data obtained from Galileo, Voyager, and ground-based observations. At least 152 active volcanic centers are now known on Io, 104 of which were discovered or confirmed by Galileo observations, including 23 from the 131 and 132 Io fly-by observations presented here. We modify the classification scheme of Keszthelyi et al. (2001, J. Geophys. Res. 106 (E12) 33 025-33 052) of Io eruption styles to include three primary types: promethean (lava flow fields emplaced as compound pahoehoe flows with small plumes < 200 km high originating from flow fronts), pillanian (violent eruptions generally accompanied by large outbursts, > 200 km high plumes and rapidly-emplaced flow fields), and a new style we call "lokian" that includes all eruptions confined within paterae with or without associated plume eruptions). Thermal maps of active paterae from NIMS data reveal hot edges that are characteristic of lava lakes. Comparisons with terrestrial analogs show that Io's lava lakes have thermal properties consistent with relatively inactive lava lakes. The majority of activity on Io, based on locations and longevity of hot spots, appears to be of this third type. This finding has implications for how Io is being resurfaced as our results imply that eruptions of lava are predominantly confined within paterae, thus making it unlikely that resurfacing is done primarily by extensive lava flows. Our conclusion is consistent with the findings of Geissler et al. (2004, Icarus, this issue) that plume eruptions and deposits, rather than the eruption of copious amounts of effusive lavas, are responsible for Io's high resurfacing rates. The origin and longevity of islands within ionian lava lakes remains enigmatic. (C) 2003 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Hawaii, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. CNRS, Lab Planetol Grenoble, F-38041 Grenoble 9, France. RP Lopes, RMC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM rlopes@lively.jpl.nasa.gov RI Turtle, Elizabeth/K-8673-2012; Lopes, Rosaly/D-1608-2016 OI Turtle, Elizabeth/0000-0003-1423-5751; Lopes, Rosaly/0000-0002-7928-3167 NR 87 TC 64 Z9 66 U1 2 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 J9 ICARUS JI Icarus PD MAY PY 2004 VL 169 IS 1 BP 140 EP 174 DI 10.1016/j.icarus.2003.11.013 PG 35 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 817MA UT WOS:000221180400009 ER PT J AU Doute, S Lopes, R Kamp, LW Carlson, R Schmitt, B AF Doute, S Lopes, R Kamp, LW Carlson, R Schmitt, B CA Galileo NIMS Team TI Geology and activity around volcanoes on Io from the analysis of NIMS spectral images SO ICARUS LA English DT Article ID INFRARED MAPPING SPECTROMETER; BOLOMETRIC ALBEDOS; GALILEO; SO2; REGOLITHS; IDENTIFICATION; PROMETHEUS; TRANSPORT; SURFACE; EUROPA AB The last two successful flybys of Io by Galileo in 2001 (orbits 131, 132) allowed the Near Infrared Mapping Spectrometer to enrich its collection of IR spectral image cubes of the satellite. These data cover hemispheric portions of Io, several volcanic centers as well as their surroundings with a spatial resolution ranging from 2 to 93 kin pixel(-1). They map thermal emission from the hot-spots and the distribution of solid SO2 in the 1.0-4.7 mum spectral range. We obtain maps of SO2 abundance and granularity from the NIMS data using the method of Doute et al. (2002, Icarus 158, 460-482). The maps are correlated to distinguish four different physical units that indicate zones of SO2 condensation, metamorphism and sublimation. We relate these information with visible images from Galileo's Solid State Imaging System and with detailed mapping of the thermal emission produced by Io's surface. Our principal goal is to understand the mechanisms controlling how lava, pyroclastics and gas are emitted by different types of volcanoes and how these products evolve. The 800 km diameter white ring of fallout created by a violent "Pillanian" eruption during summer of 2001 is at least partly composed of solid SO2 and has enriched preexisting regional deposits. Orange materials have been recently or are currently emplaced 240 km south from the main eruption site, possibly as sulfur flows. A similar event may have taken place in the past at Ababinili Patera (12.5degrees N, 142degrees W). Carefull study of SO2 maps covering the Emakong region also suggests that sulfur forms the bright channel-fed now emerging from the south eastern side of the caldera. Within the main caldera of Tvashtar Catena completely cooled patches of crust exist. Elsewhere, the caldera is still cooling from previous episodes of flooding. We confirm that Amirani emits constantly large amount of SO2 gas by interaction of fresh lava with the volatiles of the underlying plains. Nevertheless SO2 frost is not the major component of the bright white ring seen in the SSI images. Over the whole Gish Bar region, SO2 frost seems barely stable and is constantly regenerated. The stability incriases along gray filamentary structures which could be faults filled with materials having peculiar thermal properties. Northwest of Gish Bar Patera, a localized bright deposit shows an unusual spectral signature potentially indicative of H2O molecules forming ice crystals or being trapped in a nonidentified matrix. The Chaac region may present a thickened old crust reducing the geothermal flux to levels lower than 0.5 W m(-2) and thus creating a cold trap for SO2. Looking at the abundance and degree of metamorphose of SO2, we establish the relative age of different flows and ejecta for the Sobo Fluctus. Finally the assumption that the white patches in visible images indicate SO2 rich deposits is once again challenged. In the Camaxth region we identify a topographically controlled compact white deposit showing only moderate SO2 abundance. In contrast, we detect two spots of quite pure SO2 ice on the gray flanks of Emakong. Furthermore, the close association of furnarolic SO2 and red S-2 already noted for several volcanic centers is observed at Tupan. (C) 2004 Elsevier Inc. All rights reserved. C1 Lab Planetol Grenoble, F-38041 Grenoble 9, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lab Planetol Grenoble, Bat D Phys,BP 53, F-38041 Grenoble 9, France. EM sylvain.doute@obs.ujf-grenoble.fr RI Schmitt, Bernard/A-1064-2009; Lopes, Rosaly/D-1608-2016 OI Schmitt, Bernard/0000-0002-1230-6627; Lopes, Rosaly/0000-0002-7928-3167 NR 42 TC 20 Z9 20 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 MAY PY 2004 VL 169 IS 1 BP 175 EP 196 DI 10.1016/j.icarus.2004.02.001 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 817MA UT WOS:000221180400010 ER PT J AU de Pater, I Marchis, F Macintosh, BA Roe, HG Le Mignant, D Graham, JR Davies, AG AF de Pater, I Marchis, F Macintosh, BA Roe, HG Le Mignant, D Graham, JR Davies, AG TI Keck AO observations of Io in and out of eclipse SO ICARUS LA English DT Article DE Io; eclipse; adaptive optics; PSF ID INFRARED MAPPING SPECTROMETER; ADAPTIVE OPTICS IMAGES; JUPITERS MOON IO; GLOBAL DISTRIBUTION; VOLCANIC ACTIVITY; THERMAL EMISSION; HEAT-FLOW; GALILEO; DECONVOLUTION; TELESCOPE AB We present adaptive optics (AO) observations of Io taken with the W.M. Keck II telescope on 18 December 2001 (UT) before the satellite went into eclipse, and while it was in Jupiter's shadow. Making these kind of Io-in-eclipse observations, as well as the associated data reduction and analysis are challenging; hence one focus of the paper is to explain the methods and tools used for these data sets. For the sunlit images Io itself was used as the wavefront reference source, while nearby Ganymede was used as reference 'star' when Io was in eclipse. Observations were obtained in K'-, L'-, and M-bands. The sunlit images have been deconvolved using MISTRAL. The Io-in-eclipse data were deconvolved with IDAC and MISTRAL. The former gives better results, both in absolute photometry and in matching the original images. We determined the flux densities of the hot spots from the original Io-in-eclipse data with StarFinder, as well as from the deconvolved images by integrating the intensity over the relevant areas. We determined the highly anisoplanatic PSF via a FFT method from the original data, and used this in StarFinder and as a starting PSF for IDAC and MISTRAL. We derived temperatures and areal coverage of all 19 spots detected in both K'- and L'-band images of Io-in-eclipse. We also determined temperatures and areal coverage of the hot spots visible on the L'- and M-band images of sunlit Io. Most volcanoes contain a compact hot 'core' (less than or similar to10 km(2) at 600-800 K) within a larger area at lower temperatures (e.g., similar to 10(2)-10(4) km(2) at 300-500 K). The total heat flow contributed by these active volcanoes is 0.2 Wm(-2), similar to 8% of the average global heat flow measured at 5-20 mum by Veeder et al. (C) 2003 Elsevier Inc. All rights reserved. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Earth & Planetary Sci, Berkeley, CA 94720 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. WM Keck Observ, Kamuela, HI 96743 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP de Pater, I (reprint author), Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA. EM imke@floris.berkeley.edu RI Marchis, Franck/H-3971-2012 NR 45 TC 39 Z9 39 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2004 VL 169 IS 1 BP 250 EP 263 DI 10.1016/j.icarus.2003.08.025 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 817MA UT WOS:000221180400014 ER PT J AU Veeder, GJ Matson, DL Johnson, TV Davies, AG Blaney, DL AF Veeder, GJ Matson, DL Johnson, TV Davies, AG Blaney, DL TI The polar contribution to the heat flow of Io SO ICARUS LA English DT Article DE Io; volcanism; thermal; infrared ID INFRARED MAPPING SPECTROMETER; THERMAL EMISSION; VOLCANIC HOTSPOTS; ACTIVE VOLCANISM; RADIOMETRY AB Polar brightness temperatures on Io are higher than expected for any passive surface heated by absorbed sunlight. This discrepancy implies large scale volcanic activity from which we derive a new component of Io's heat flow. We present a 'Three Component' thermal background, infrared emission model for Io that includes active polar regions. The widespread polar activity contributes an additional similar to 0.6 W m(-2) to Io's heat flow budget above the similar to 2.5 W m(-2) from thermal anomalies. Our estimate for Io's global average heat flow increases to similar to 3 +/- 1 W m(-2) and similar to 1.3 +/- 0.4 x 10(14) watts total. (C) 2003 Published by Elsevier Inc. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Veeder, GJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM glenn.veeder@jpl.nasa.gov NR 45 TC 20 Z9 21 U1 1 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 J9 ICARUS JI Icarus PD MAY PY 2004 VL 169 IS 1 BP 264 EP 270 DI 10.1016/j.icarus.2003.11.016 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 817MA UT WOS:000221180400015 ER PT J AU Liu, JH Simon, M Stoica, P Li, H AF Liu, JH Simon, M Stoica, P Li, H TI A soft-detector based on multiple symbol detection for double differential modulation SO IEEE COMMUNICATIONS LETTERS LA English DT Article DE double differential (DD) modulation; multiple symbol detection; soft-detection AB We consider the problem of soft-detection for communication systems employing double differential modulation and forward error correction codes, for example, a convolutional code. We propose a soft-detector with low computational complexity. Simulation results are provided to show the superior performance of the new soft-detector. C1 Univ Florida, Dept Elect & Comp Engn, Gainesville, FL 32611 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Uppsala Univ, Dept Informat Technol, Div Syst & Control, SE-75105 Uppsala, Sweden. RP Liu, JH (reprint author), Univ Florida, Dept Elect & Comp Engn, Gainesville, FL 32611 USA. EM jhliu@dsp.ufl.edu NR 8 TC 0 Z9 2 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1089-7798 J9 IEEE COMMUN LETT JI IEEE Commun. Lett. PD MAY PY 2004 VL 8 IS 5 BP 296 EP 298 DI 10.1109/LCOMM.2004.827436 PG 3 WC Telecommunications SC Telecommunications GA 821MQ UT WOS:000221465400012 ER PT J AU Cheng, Y Goguen, J Johnson, A Leger, C Matthies, L San Martin, M Willson, R AF Cheng, Y Goguen, J Johnson, A Leger, C Matthies, L San Martin, M Willson, R TI The Mars exploration rovers descent image motion estimation system SO IEEE INTELLIGENT SYSTEMS LA English DT Editorial Material C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Jet Prop Lab, Pasadena, CA 91109 USA. EM robotics@jpl.nasa.gov; jay.goguen@jpl.nasa.gov; aej@jpl.nasa.gov; cleger@robotics.jpl.nasa.gov; lhm@robotics.jpl.nasa.gov; miguel.sanmartin@jpl.nasa.gov; rwillson@jpl.nasa.gov NR 4 TC 41 Z9 45 U1 0 U2 3 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1541-1672 EI 1941-1294 J9 IEEE INTELL SYST JI IEEE Intell. Syst. PD MAY-JUN PY 2004 VL 19 IS 3 BP 13 EP 21 DI 10.1109/MIS.2004.18 PG 9 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 823RB UT WOS:000221629600005 ER PT J AU Filman, R AF Filman, R TI Days of miracle and wonder SO IEEE INTERNET COMPUTING LA English DT Editorial Material C1 NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. RP Filman, R (reprint author), NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. NR 7 TC 0 Z9 0 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 1089-7801 J9 IEEE INTERNET COMPUT JI IEEE Internet Comput. PD MAY-JUN PY 2004 VL 8 IS 3 BP 4 EP 6 DI 10.1109/MIC.2004.1273478 PG 3 WC Computer Science, Software Engineering SC Computer Science GA 818PC UT WOS:000221256000001 ER PT J AU Kutyrev, AS Arendt, R Moseley, SH Boucarut, RA Hadjimichael, T Jhabvala, M King, T Li, MJ Loughlin, J Rapchun, D Schwinger, DS Silverberg, RF AF Kutyrev, AS Arendt, R Moseley, SH Boucarut, RA Hadjimichael, T Jhabvala, M King, T Li, MJ Loughlin, J Rapchun, D Schwinger, DS Silverberg, RF TI Programmable microshutter arrays for the JWST NIRSpec: Optical performance SO IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS LA English DT Article DE actuation; James Webb Space Telescope (JWST); microelectromechanical systems (MEMS); micromirror arrays; micro-optics; microshutters; planar structures; programmable masks; spatial light modulator AB Two-dimensional microshutter arrays (MSAs) are being developed at the NASA Goddard Space Flight Center for the James Webb Space Telescope (JWST) for use as a programmable aperture mask for object selection for the Near Infrared Multiobject Spectrograph (NIRSpec). The MSAs are designed to provide high transmission efficiency for the selected objects and high on to off contrast ratio at the similar to35 K operating temperature of JWST. The arrays of shutters are produced from silicon nitride membranes on a 100 x 200 mum pitch. Individual shutters consist of a shutter blade of silicon nitride suspended from the shutter frame by a nitride torsion flexure. The shutters are normally closed. All shutters in the array are opened by the scanning magnetic field, and are held open by an electrostatic potential applied between the open shutters and the shutter support grid electrodes. To close the required shutters for a specific configuration, the potential between the shutter to be deselected and the support frame is set to zero, allowing the shutter to close. In this way, full random access addressing is achieved. We have produced such shutters and have demonstrated mechanical actuation and selection. Optical tests of open and closed shutters have demonstrated the required contrast for the JWST application. The MSA is a pioneering technology that provides the most capable possible multiobject spectrograph for JWST. It provides high contrast selection, high transmission efficiency, and can meet the environmental requirements for JWST. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kutyrev, AS (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM kutyrev@gsfc.nasa.gov NR 6 TC 15 Z9 15 U1 0 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1077-260X J9 IEEE J SEL TOP QUANT JI IEEE J. Sel. Top. Quantum Electron. PD MAY-JUN PY 2004 VL 10 IS 3 BP 652 EP 661 DI 10.1109/JSTQE.2004.830614 PG 10 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 846EX UT WOS:000223299300030 ER PT J AU Tang, YL Chen, PY Wang, H AF Tang, YL Chen, PY Wang, H TI A broadband PHEMT MMIC distributed doubler using high-pass drain line topology SO IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS LA English DT Article DE broadband; distributed doubler; frequency doubler; MMIC; PHEMT AB A broadband frequency doubler, based on distributed amplifier techniques, has been designed to operate from 11 to 21 GHz. In order to reject the fundamental signal over a broadband frequency range, the conventional low-pass drain line structure was replaced with the high-pass structure. This topology can suppress fundamental signals over broadband without any balanced structure so that the chip size can be more compact. Measured conversion losses of better than 10 dB from 11 to 21 GHz; input frequencies are achieved with fundamental signal rejection better than 12 dB. To the best of our knowledge, this is the first demonstration of distributed doubler using the high-pass drain line topology. C1 Natl Taiwan Univ, Grad Inst Commun Engn, Taipei 10764, Taiwan. RP Wang, H (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM hueiwang@ew.ee.ntu.edu.tw NR 9 TC 14 Z9 15 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1531-1309 J9 IEEE MICROW WIREL CO JI IEEE Microw. Wirel. Compon. Lett. PD MAY PY 2004 VL 14 IS 5 BP 201 EP 203 DI 10.1109/LMWC.2004.827860 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 819KJ UT WOS:000221313500005 ER PT J AU Chakrabarti, S Stiff-Roberts, AD Bhattacharya, P Gunapala, S Bandara, S Rafol, SB Kennerly, SW AF Chakrabarti, S Stiff-Roberts, AD Bhattacharya, P Gunapala, S Bandara, S Rafol, SB Kennerly, SW TI High-temperature operation of InAs-GaAs quantum-dot infrared photodetectors with large responsivity and detectivity SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE detectivity; InAs-GaAs; infrared detector; quantum dots; responsivity ID PHOTOCONDUCTIVITY AB We have optimized the growth of multiple (40-70) layers of self-organized InAs quantum dots separated by GaAs barrier layers in order to enhance the absorption of quantum-dot infrared photodetectors (QDIPs). In devices with 70 quantum-dot layers, at relatively large operating biases (less than or equal to -1.0 V), the dark current density is as low as 10(-5) A/cm(2) and the peak responsivity ranges from similar to0.1 to 0.3 A/W for temperatures T = 150 K - 175 K. The peak detectivity corresponding to these low dark currents and high responsivities varies in the range 6 x 10(9) less than or equal to D-* (cm . Hz(1/2)/W) less than or equal to 10(11) for temperatures 100 less than or equal to T(K) less than or equal to 200. These performance characteristics represent the state-of-the-art for QDIPs and indicate that this device heterostructure is appropriate for incorporation into focal plane arrays. C1 Univ Michigan, Dept Elect Engn & Comp Sci, Solid State Elect Lab, Ann Arbor, MI 48109 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. USA, Res Lab, Sensors & Electron Devices Directorate, Adelphi, MD 20783 USA. RP Bhattacharya, P (reprint author), Univ Michigan, Dept Elect Engn & Comp Sci, Solid State Elect Lab, Ann Arbor, MI 48109 USA. EM pkb@eecs.umich.edu NR 12 TC 130 Z9 131 U1 5 U2 32 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD MAY PY 2004 VL 16 IS 5 BP 1361 EP 1363 DI 10.1109/LPT.2004.825974 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 815TI UT WOS:000221064200046 ER PT J AU Wang, JB Simon, MK Yao, K AF Wang, JB Simon, MK Yao, K TI On the optimum design of unitary cyclic group space-time codes SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article; Proceedings Paper CT IEEE Global Telecommunication Conference (GLOBCOM) CY DEC 01-05, 2003 CL San Francisco, CA SP IEEE, ICC, IEEE Commun Soc DE cyclic group codes; differential unitary space-time (DUST) coding; pairwise-error probability (PEP); union bound ID MODULATION AB In this letter, based on the exact pairwise-error probability, we derive the union bound on the symbol-error probability (SEP) of the differential unitary space-time (DUST) modulation employing group codes. Instead of using the rank-and-determinant or Euclidean distance criteria, we optimize the cyclic group codes such that the union bound on the SEP is minimized for a predetermined scenario, taking into account the number of transmit and receive antennas and the operating signal-to-noise ratio (SNR). Our simulation results show that for a wide range of SNRs, the codes with the minimum union bound for a particular SNR outperform the codes designed based on rank-and-determinant or Euclidean distance criteria. C1 NEC Labs Amer Inc, Princeton, NJ 08540 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90024 USA. RP Wang, JB (reprint author), NEC Labs Amer Inc, Princeton, NJ 08540 USA. EM wangjb@nec-labs.com; marvin.k.simon@jpl.nasa.gov NR 18 TC 10 Z9 11 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 MAY PY 2004 VL 52 IS 5 BP 706 EP 710 DI 10.1109/TCOMM.2004.826256 PG 5 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 822YG UT WOS:000221576200007 ER PT J AU Kuhn, WB He, X Mojarradi, M AF Kuhn, WB He, X Mojarradi, M TI Modeling spiral inductors in SOS processes SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article DE eddy currents; inductors; modeling; silicon-on-insulator (SOI) technology; SPICE ID COMPACT MODEL; RF ICS; SILICON; DESIGN AB Existing models for simulating spiral inductors fabricated in Silicon processes are outgrowths of the PI structure originally employed by Nguyen and Meyer. This structure and its subsequent elaborations work well for inductors in which the dominant loss mechanism is the underlying substrate. For newer processes with very high resistivity or insulating substrates such as Silicon-on-sapphire however, the model breaks down since inductor quality factor Q is then determined predominantly by series trace resistance. Models suitable for use in such processes are proposed and compared with measured data. The new models contain only four to six elements and, unlike the classic PI model, provide a broadband match to measured impedance behavior in both differentially driven and single-ended circuit applications. C1 Kansas State Univ, Dept Elect & Comp Engn, Manhattan, KS 66506 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Kuhn, WB (reprint author), Kansas State Univ, Dept Elect & Comp Engn, Manhattan, KS 66506 USA. NR 15 TC 18 Z9 18 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9383 EI 1557-9646 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD MAY PY 2004 VL 51 IS 5 BP 677 EP 683 DI 10.1109/TED.2004.826868 PG 7 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 816NT UT WOS:000221117300005 ER PT J AU Skofronick-Jackson, GM Kim, MJ Weinman, JA Chang, DE AF Skofronick-Jackson, GM Kim, MJ Weinman, JA Chang, DE TI A physical model to determine snowfall over land by microwave radiometry SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE electromagnetic scattering; estimation; millimeter-wave radiometry; remote sensing; satellite; snow ID ICE CRYSTALS; MILLIMETER WAVELENGTHS; SURFACE EMISSIVITY; ATLANTIC CYCLONE; NATURAL CLOUDS; RADAR; PRECIPITATION; HYDROMETEORS; MESOSCALE; CIRRUS AB Falling snow is an important component of global precipitation in extratropical regions. This paper describes the methodology and results of physically based retrievals of snow failing over land surfaces. Because microwave brightness temperatures emitted by snow-covered surfaces are highly variable, precipitating snow above such surfaces is difficult to observe using window channels that occur at low frequencies (nu < 100 GHz). Furthermore, at frequencies nu < 37 GHz, sensitivity to liquid hydrometeors is dominant. These problems are mitigated at high frequencies (nu > 100 GHz) where water vapor screens the surface emission, and sensitivity to frozen hydrometeors is significant. However, the scattering effect of snowfall in the atmosphere at those higher frequencies is also impacted by water vapor in the upper atmosphere. The theory of scattering by randomly oriented dry snow particles at high microwave frequencies appears to be better described by regarding snow as a concatenation of "equivalent" ice spheres rather than as a sphere with the effective dielectric constant of an air-ice mixture. An equivalent sphere snow scattering model was validated against high-frequency attenuation measurements. Satellite-based high-frequency observations from an Advanced Microwave Sounding Unit (AMSU-B) instrument during the March 5-6, 2001 New England blizzard were used to retrieve snowfall over land. Vertical distributions of snow, temperature, and relative humidity profiles were derived from the Mesoscale Model (MM5) cloud model. Those data were applied and modified in a radiative transfer model that derived brightness temperatures consistent with the AMSU-B observations. The retrieved snowfall distribution was validated with radar reflectivity measurements obtained from a ground-based radar network. C1 NASA, Goddard Space Flight Ctr, Microwave Sensors Branch, Greenbelt, MD 20771 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. RP Skofronick-Jackson, GM (reprint author), NASA, Goddard Space Flight Ctr, Microwave Sensors Branch, Greenbelt, MD 20771 USA. EM gails-jackson@ieee.org RI Skofronick-Jackson, Gail/D-5354-2012 NR 39 TC 60 Z9 60 U1 1 U2 9 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 2004 VL 42 IS 5 BP 1047 EP 1058 DI 10.1109/TGRS.2004.825585 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 821MX UT WOS:000221466200012 ER PT J AU Hall, DK Key, JR Casey, KA Riggs, GA Cavalieri, DJ AF Hall, DK Key, JR Casey, KA Riggs, GA Cavalieri, DJ TI Sea ice surface temperature product from MODIS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE advanced microwave scanning radiometer-EOS; (AMSR-E); ice-surface temperature; moderate-resolution imaging spectroradiometer (MODIS); sea ice ID RESOLUTION IMAGING SPECTRORADIOMETER; CLEAR-SKY; TRENDS; CLOUD; CLASSIFICATION; VARIABILITY; RADIOMETER; EXTENT; ACCURACY; WATER AB Global sea ice products are produced from the Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) onboard both the Terra and Aqua satellites. Daily sea ice extent and ice surface temperature (IST) products are available at 1- and 4-km resolution. Validation activities during the "cold period" (when meltwater is generally not present) in the Northern Hemisphere, defined here as October through May, have been undertaken to assess the accuracy of the I-km resolution MODIS IST algorithm and product. Validation was also done at the South Pole station in Antarctica. In the Arctic Ocean, near-surface air temperatures from the National Oceanic and Atmospheric Administration (NOAA) National Ocean Service (NOS) Center for Operational Oceanographic Products and Services (CO-OPS) Alaska tide stations and from drifting buoys from the North Pole Environmental Observatory (NPEO) buoy program were compared with MODIS-derived ISTs. Using the standard MODIS sea ice product, which utilizes the MODIS cloud mask, results show a bias (mean error) of -2.1 K and a root mean square (RMS) error of 3.7 K. The negative bias means that the satellite retrieval is less than the air temperature. With the bias removed, the RMS error is 3.0 K. When additional visual cloud screening is performed to eliminate MODIS pixels thought to be contaminated by fog, results improved, with a subset of the larger dataset showing a bias of -0.9 K and an RMS error of 1.6 K. Uncertainties would be reduced in the Arctic Ocean dataset if the skin temperature of the sea ice were reported instead of the near-surface air temperatures. With the bias removed, the RMS error for the Arctic Ocean dataset is 1.3 K. Results from the South Pole station in Antarctica show that under clear skies as determined using lidar measurements, the MODIS ISTs are also very close to those of the near-surface air temperatures with a bias of -1.2 K and an RMS error of 1.7 K. With the bias removed, the RMS error for the South Pole dataset is 1.2 K. Thus, the accuracy (RMS error) of the IST measurement is 1.2-1.3 K. It is not possible to obtain an accurate IST from MODIS in the presence of even very thin clouds or fog, and this is the main limitation of the MODIS ice surface temperature product. MODIS sea ice products may be ordered from the National Snow and Ice Data Center in Boulder, CO. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA Natl Environm satellite, Data & Informat Serv, Madison, WI 53706 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP Hall, DK (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM dorothy.k.hall@nasa.gov RI Key, Jeffrey/F-5597-2010; Hall, Dorothy/D-5562-2012; Casey, Kimberly/A-4478-2013 OI Key, Jeffrey/0000-0001-6109-3050; Casey, Kimberly/0000-0002-6115-7525 NR 55 TC 74 Z9 76 U1 2 U2 23 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 2004 VL 42 IS 5 BP 1076 EP 1087 DI 10.1109/TGRS.2004.825587 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 821MX UT WOS:000221466200015 ER PT J AU Jeong, SI Seyed-Yagoobi, J AF Jeong, SI Seyed-Yagoobi, J TI Innovative electrode designs for electrohydrodynamic conduction pumping SO IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS LA English DT Article; Proceedings Paper CT 37th Annual Meeting of the IEEE-Industry-Applications-Society CY OCT 12-18, 2002 CL PITTSBURGH, PA SP IEEE Ind Appl Soc DE conduction phenomenon; dielectric fluids; electrohydrodynamic (EHD); nonmechanical pumping; pressure head generation AB In the absence of a direct charge injection, pumping of an isothermal liquid can be achieved through the charges associated with the heterocharge layers of finite thickness in the vicinity of the electrodes. These charges are based on the process of dissociation of a neutral electrolytic species and recombination of the generated ions. This type of pumping is referred to as electrohydrodynamic (EHD) conduction pumping. The EHD conduction pumping mechanism is experimentally investigated with four innovative electrode designs, with refrigerant R-123 as the working fluid in this paper. Specifically, two different types of perforated disks and two different types of porous disks are used as the high-voltage electrode while a ring is used as the common ground electrode for the four designs. Pressures up to approximately 1400 Pa (at 18.5-kV potential with 0.23 W of power consumption) are generated with one electrode pair. Such pressure generations make the EHD conduction pumping attractive to certain applications in the presence and absence of gravity, such as capillary pumped loops and heat pipes. C1 Texas A&M Univ, Dept Mech Engn, College Stn, TX 77843 USA. IIT, Dept Mech Mat & Aerosp Engn, Chicago, IL 60616 USA. RP Jeong, SI (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM sjeong@mscmail.gsfc.nasa.gov; yagoobi@iit.edu NR 12 TC 18 Z9 18 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0093-9994 J9 IEEE T IND APPL JI IEEE Trans. Ind. Appl. PD MAY-JUN PY 2004 VL 40 IS 3 BP 900 EP 904 DI 10.1109/TIA.2004.827771 PG 5 WC Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA 822YU UT WOS:000221577700024 ER PT J AU Chattopadhyay, G Schlecht, E Ward, JS Gill, JJ Javadi, HHS Maiwald, F Medhi, I AF Chattopadhyay, G Schlecht, E Ward, JS Gill, JJ Javadi, HHS Maiwald, F Medhi, I TI An all-solid-state broad-band frequency multiplier chain at 1500 GHz SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE balanced doubler; broad-band solid-state multipliers; Schottky-barrier diode ID SUBMILLIMETER WAVELENGTHS; SCHOTTKY VARACTOR; OSCILLATOR; OPTIMIZATION; MILLIMETER; GAAS AB We report the results of a high-performance all-solid-state broad-band frequency multiplier chain at 1500 GHz, which uses four cascaded planar Schottky-barrier varactor doublers. The multipliers are driven by monolithic-microwave integrated-circuit-based high electron-mobility transistor power amplifiers around 95 GHz with 100-150 mW of pump power. The design incorporates balanced doublers utilizing novel substrateless and membrane device fabrication technologies, achieving low-loss broad-band multipliers working in the terahertz range. For a drive power of approximately 100 mW in the 88-99-GHz range, the doublers achieved room-temperature peak efficiencies of approximately 30% at the 190-GHz stage, 20% at 375 GHz, 9% at 750 GHz, and 4% at the 1500-GHz stage. When the chain was cooled to 120 K, approximately 40 muW of peak output power was measured for 100 mW of input pump power. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Chattopadhyay, G (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 28 TC 94 Z9 97 U1 1 U2 9 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD MAY PY 2004 VL 52 IS 5 BP 1538 EP 1547 DI 10.1109/TMTT.2004.827042 PG 10 WC Engineering, Electrical & Electronic SC Engineering GA 818GH UT WOS:000221233100021 ER PT J AU Lee, MMS Keerthi, SS Ong, CJ DeCoste, D AF Lee, MMS Keerthi, SS Ong, CJ DeCoste, D TI An efficient method for computing leave-one-out error in support vector machines with Gaussian kernels SO IEEE TRANSACTIONS ON NEURAL NETWORKS LA English DT Article DE leave-one-out (LOO) error; support vector machines (SVMs) ID SMO ALGORITHM AB In this paper, we give an efficient method for computing the leave-one-out (LOO) error for support vector machines (SVMs) with Gaussian kernels quite accurately. It is particularly suitable for iterative decomposition methods of solving SVMs. The importance of various steps of the method is illustrated in detail by showing the performance on six benchmark datasets. The new method often leads to speedups of 10-50 times compared to standard LOO error computation. It has good promise for use in hyperparameter tuning and model comparison. C1 Natl Univ Singapore, Dept Mech Engn, Singapore 117548, Singapore. CALTECH, Jet Prop Lab, Machine Learning Syst Grp, Pasadena, CA 91109 USA. RP Natl Univ Singapore, Dept Mech Engn, Singapore 117548, Singapore. EM Dennis.DeCoste@jpl.nasa.gov NR 16 TC 29 Z9 37 U1 1 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1045-9227 EI 1941-0093 J9 IEEE T NEURAL NETWOR JI IEEE Trans. Neural Netw. PD MAY PY 2004 VL 15 IS 3 BP 750 EP 757 DI 10.1109/TNN.2004.824266 PG 8 WC Computer Science, Artificial Intelligence; Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 821SU UT WOS:000221483700018 PM 15384561 ER PT J AU Clancey, WJ AF Clancey, WJ TI Roles for agent assistants in field science: Understanding personal projects and collaboration SO IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART C-APPLICATIONS AND REVIEWS LA English DT Article DE assistants; collaborative work; consciousness; field science; model-based systems; robots ID SYSTEMS AB A human-centered approach to computer systems design involves refraining analysis in terms of the people interacting with each other. The primary concern is not how people can interact with computers, but how work systems (facilities, tools, roles, and procedures) can be designed to help people pursue their personal projects, as they work independently and collaboratively. Two case studies provide empirical requirements. First, an analysis of astronaut interactions with CapCom on Earth during one traverse of Apollo 17 shows what kind of information was conveyed and what might be automated today. A variety of agent and robotic technologies are proposed that deal with recurrent problems in communication and coordination during the analyzed traverse. Second, an analysis of biologists and a geologist working at Haughton Crater in the High Canadian Arctic reveals how work interactions between people involve independent personal projects, sensitively coordinated for mutual benefit. In both cases, an agent or robotic system's role would be to assist people, rather than collaborating, because today's computer systems lack the identity and purpose that consciousness provides. C1 NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94035 USA. RP Clancey, WJ (reprint author), NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94035 USA. EM william.j.clancey@nasa.gov NR 24 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 1094-6977 J9 IEEE T SYST MAN CY C JI IEEE Trans. Syst. Man Cybern. Part C-Appl. Rev. PD MAY PY 2004 VL 34 IS 2 BP 125 EP 137 DI 10.1109/TSMCC.2004.826284 PG 13 WC Computer Science, Artificial Intelligence; Computer Science, Cybernetics; Computer Science, Interdisciplinary Applications SC Computer Science GA 815ML UT WOS:000221046300004 ER PT J AU Lee, PUJ Zhai, SM AF Lee, PUJ Zhai, SM TI Top-down learning strategies: can they facilitate stylus keyboard learning? SO INTERNATIONAL JOURNAL OF HUMAN-COMPUTER STUDIES LA English DT Article ID MEMORY AB Learning a new Stylus keyboard layout is time-consuming yet potentially rewarding, its optimized virtual keyboards can substantially increase performance for expert users. This paper explores whether the learning curve can be accelerated using top-down learning strategies. In an experiment, one group of participants learned a Stylus keyboard layout with top-down methods, Such as visuo-spatial grouping of letters and mnemonic techniques, to build familiarity With a Stylus keyboard. The other (Control) group learned the keyboard by typing sentences. The top-down learning group liked the stylus keyboard better and perceived it to be more effective than the control group. They also had better memory recall performance. Typing performance after the top-down learning process was faster than the initial performance of the control group, but not different from the performance of the control group after they had spent an equivalent amount of time typing. Therefore, top-down learning strategies improved the explicit recall as expected, but the improved memory of the keyboard did not result in quicker typing speeds. These results suggest that quicker acquisition Of declarative knowledge does not improve the acquisition speed of procedural knowledge, even during the initial cognitive stage of the virtual keyboard learning. They also Suggest that top-down learning strategies can motivate users to learn a new keyboard more than repetitive rehearsal, without any loss in typing performance. (C) 2004 Elsevier Ltd. All rights reserved. C1 San Jose State Univ, NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. IBM Corp, Almaden Res Ctr, San Jose, CA 95120 USA. RP Lee, PUJ (reprint author), San Jose State Univ, NASA, Ames Res Ctr, Mail Stop 262-4, Moffett Field, CA 94035 USA. EM plee@mail.arc.nasa.gov; zhai@almaden.ibm.com NR 22 TC 11 Z9 11 U1 1 U2 4 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1071-5819 J9 INT J HUM-COMPUT ST JI Int. J. Hum.-Comput. Stud. PD MAY PY 2004 VL 60 IS 5-6 BP 585 EP 598 DI 10.1016/j.ijhcs.2003.10.009 PG 14 WC Computer Science, Cybernetics; Ergonomics; Psychology, Multidisciplinary SC Computer Science; Engineering; Psychology GA 810WQ UT WOS:000220734800005 ER PT J AU Nieto, MM Turyshev, SG AF Nieto, MM Turyshev, SG TI Measuring the interplanetary medium with a solar sail SO INTERNATIONAL JOURNAL OF MODERN PHYSICS D LA English DT Article DE interstellar medium; solar sail ID KUIPER-BELT; NEPTUNE; MISSION AB NASA has been considering a solar sail that would accelerate a craft to a high velocity (similar to14 AU/yr) by the time it reached 5 AU. Then the sail would be dropped and the craft would coast alone to deep space. We propose that the sail be retained longer. Then the density of the interplanetary medium could be determined by measuring the drag force on the huge sail using radiometric navigational data. Such an experiment would yield an independent, new type of measurement of the interplanetary medium and should be pursued. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nieto, MM (reprint author), Los Alamos Natl Lab, Div Theoret, POB 1663,MS-B285, Los Alamos, NM 87545 USA. EM mmn@lanl.gov; turyshev@jpl.nasa.gov NR 15 TC 4 Z9 4 U1 0 U2 2 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-2718 J9 INT J MOD PHYS D JI Int. J. Mod. Phys. D PD MAY PY 2004 VL 13 IS 5 BP 899 EP 906 DI 10.1142/S0218271804004955 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 834SK UT WOS:000222430900010 ER PT J AU Carter, GA Freedman, A Kebabian, PL Scott, HE AF Carter, GA Freedman, A Kebabian, PL Scott, HE TI Use of a prototype instrument to detect short-term changes in solar-excited leaf fluorescence SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID PHOTOSYNTHETIC RATE; PLANT FLUORESCENCE; STRESS DETECTION AB A prototype instrument was used under clear skies to determine the efficacy of the Fraunhofer Line-Depth Principle in detecting short-term (less than one day) changes in solar-excited fluorescence (F) as an indicator of plant physiological status. Corn (Zea mays L. var. Shoe Peg) and soybean (Glycine max L. var. Hutcheson) plants grown in pots outdoors were either assigned as controls or treated with bromacil, a photosystem II herbicide. The Plant Fluorescence System (PFS) measured the radiant flux of F and total upwelling radiant flux (M) from individual leaves in 10 nm bandwidths centred at 690 nm and 760 nm. The herbicide lowered (p = 0.01) net photosynthetic CO2 assimilation rates to negative values in both species. In corn, this corresponded with increases in mean F to 5.9 mW m(-2) nm(-1) and 3.8 mW m(-2) nm 21 at 690nm and 760 nm, respectively, approximately twice control values. In soybean, mean F at 760 nm increased from 2.6 mW m(-2) nm(-1) to 3.8 mW m(-2) nm(-1), whereas F at 690nm was unaffected. Leaf chlorophyll contents were unaffected by treatment. Although the stress induced was drastic, these changes in F increased M by only 1-2%, demonstrating the high radiometric sensitivity required for detection. It is expected that, for whole plant canopies, a still greater variability in F among leaves would further reduce its apparent contribution to M. C1 NASA, Earth Sci Applicat Directorate, Stennis Space Ctr, MS 39529 USA. Aerodyne Res Inc, Ctr Sensor Syst & Technol, Billerica, MA 01821 USA. RP Carter, GA (reprint author), Univ So Mississippi, Gulf Coast Geospatial Ctr, POB 7000,703 E Beach Dr, Ocean Springs, MS 39564 USA. EM greg.carter@usm.edu NR 14 TC 8 Z9 11 U1 2 U2 6 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD MAY PY 2004 VL 25 IS 9 BP 1779 EP 1784 DI 10.1080/01431160310001619544 PG 6 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 805YI UT WOS:000220401200015 ER PT J AU Gorlenko, V Tsapin, A Namsaraev, Z Teal, T Tourova, T Engler, D Mielke, R Nealson, K AF Gorlenko, V Tsapin, A Namsaraev, Z Teal, T Tourova, T Engler, D Mielke, R Nealson, K TI Anaerobranca californiensis sp nov., an anaerobic, alkalithermophilic, fermentative bacterium isolated from a hot spring on Mono Lake SO INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY LA English DT Article AB A novel, obligately anaerobic, alkalithermophilic, chemo-organotrophic bacterium was isolated from the sediment of an alkaline hot spring located on Paoha Island in Mono Lake, California, USA. This rod-shaped bacterium was motile via peritrichous flagella. Isolated strains grew optimally in 5-25 g NaCl l(-1), at pH 9.0-9.5 and at a temperature of 58degreesC and were fermentative and mainly proteolytic, utilizing peptone, Casamino acids and yeast extract. Optimal growth was seen in the presence of elemental sulfur, polysulfide or thiosulfate with concomitant reduction to hydrogen sulfide. Sulfite was also formed in an equal ratio to sulfide during reduction of thiosulfate. The novel isolate could also reduce Fe(III) and Se(IV) in the presence of organic matter. On the basis of physiological properties, 16S rRNA gene sequence and DNA-DNA hybridization data, strain PAOHA-1(T) (=DSM 14826(T)=UNIOEM 227(T)) belongs to the genus Anaerobranca and represents a novel species, Anaerobranca californiensis sp. nov. C1 Russian Acad Sci, Inst Microbiol, Moscow 117811, Russia. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ So Calif, Los Angeles, CA 90089 USA. CALTECH, Pasadena, CA 91125 USA. RP Gorlenko, V (reprint author), Russian Acad Sci, Inst Microbiol, Moscow 117811, Russia. EM vgorlenko@mail.ru NR 14 TC 43 Z9 46 U1 1 U2 11 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 MAY PY 2004 VL 54 BP 739 EP 743 DI 10.1099/ijs.0.02909-0 PN 3 PG 5 WC Microbiology SC Microbiology GA 822ZM UT WOS:000221579500017 PM 15143017 ER PT J AU Bolonkin, A AF Bolonkin, A TI Hypersonic gas-rocket launcher of high capacity SO JBIS-JOURNAL OF THE BRITISH INTERPLANETARY SOCIETY LA English DT Article; Proceedings Paper CT World Space Congress CY OCT 10-19, 2002 CL Houston, TX DE hypersonic launcher; space launcher; gas rocket AB The present contribution describes a hypersonic gas rocket that uses tube walls as a container for moving compressed air. Burn programmes (fuel injections) are suggested that enable the internal tube components to be used as a rocket. A long tube (up to 0.4-0.8 km) is located in the sea and provides mobility and serves as an aiming device. Relatively inexpensive oxidizer and fuel are used (compressed air or gaseous oxygen and kerosene). When a projectile crosses the Earth's atmosphere with an angle of more then 15(0), then the loss of speed and the weight of the required thermal protection system are small. The research shows that the launcher can give a projectile a speed of up to 5-8 km/sec. The proposed launcher can deliver up to 85,000 tons of payload to space annually at a cost of one to two dollars per pound of payload. The launcher can also deliver about 500 tons of mail or express parcels per day over continental distances, and can be used as an energy station and accumulator. During war, this launch system could deliver military munitions to targets thousands to tens of thousands of kilometers away from the launch site. C1 NASA, NRC, Brooklyn, NY 11229 USA. RP Bolonkin, A (reprint author), USA, NRC, Eglin AFB, FL USA. EM aBolonkin@juno.com NR 15 TC 3 Z9 3 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 MAY-JUN PY 2004 VL 57 IS 5-6 BP 162 EP 172 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Engineering; Astronomy & Astrophysics; Geology GA 810NY UT WOS:000220712200001 ER PT J AU Hall, RM Woodson, SH AF Hall, RM Woodson, SH TI Introduction to the Abrupt Wing Stall Program SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut AB The Abrupt Wing Stall (AWS) Program has addressed the problem of uncommanded, transonic lateral motions, such as wing drop, with experimental, computational, and simulation tools. Background to the establishment of the AWS program is given as well as program objectives. To understand the fundamental flow mechanisms that caused the undesirable motions for a preproduction version of the F/A-18E, steady and unsteady flowfield details were gathered from dedicated transonic wind-tunnel testing and computational studies. The AWS program has also adapted a free-to-roll (FTR) wind-tunnel testing technique traditionally used for low-speed studies of lateral dynamic stability to the transonic flow regime. This FTR capability was demonstrated first in a proof-of-concept study and then applied to an assessment of four different aircraft configurations. Figures of merit for static testing and for FTR testing have been evaluated for two configurations that demonstrated wing-drop susceptibility during full-scale flight conditions (the preproduction F/A-18E and the AV-8B at the extremes of its flight envelope) and two configurations that do not exhibit wing drop (the F/A-18C and the F-16C). Design insights have been obtained from aerodynamic computational studies of the four aircraft configurations and from computations quantifying the impact of the various geometric wing differences between the F/A-18C and the F/A-18E wings. Finally, the AWS program provides guidance for assessing, in the simulator, the impact of experimentally determined lateral activity on flight characteristics before going to flight. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. USN, Air Syst Command, Patuxent River, MD 20670 USA. RP Hall, RM (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 33 TC 15 Z9 18 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2004 VL 41 IS 3 BP 425 EP 435 DI 10.2514/1.3630 PG 11 WC Engineering, Aerospace SC Engineering GA 828OC UT WOS:000221981600001 ER PT J AU Chambers, JR Hall, RM AF Chambers, JR Hall, RM TI Historical review of uncommanded lateral-directional lotions at transonic conditions SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut AB This paper presents the results of a survey of past experiences with uncommanded lateral-directional motions at transonic speeds during specific military aircraft programs. The effort was undertaken to provide qualitative and quantitative information on past airplane programs that might be of use to the participants in the joint NASA/Navy/Air Force Abrupt Wing Stall Program. The Abrupt Wing Stall (AWS) Program was initiated because of the experiences of the F/A-18E/F development program, during which unexpected, severe wing-drop motions were encountered by preproduction aircraft at transonic conditions. These motions were judged to be significantly degrading to the primary mission requirements of the aircraft. Although the problem was subsequently solved for the production version of the F/A-18E/F, a high-level review panel emphasized the poor understanding of such phenomena and issued a strong recommendation to "initiate a national research effort to thoroughly and systematically study the wing drop phenomena." A comprehensive, cooperative NASA/Navy/Air Force AWS Program was designed to respond to provide the required technology requirements. A work element was directed at a historical review of wing-drop experiences in past aircraft development programs at high subsonic and transonic speeds. In particular, information was requested regarding: specific aircraft configurations that exhibited uncommanded motions and the nature of the motions; geometric characteristics of the airplanes; flight conditions involved in occurrences; relevant data, including wind-tunnel, computational, and flight sources; figures of merit used for analyses; and approaches used to alleviate the problem. An attempt was also made to summarize some of the more important lessons learned from past experiences and to recommend specific research efforts. C1 Ball Aerosp Syst Div, Fairborn, OH 45324 USA. NASA, Langley Res Ctr, Configurat Aerodynam Branch, Hampton, VA 23681 USA. RP Chambers, JR (reprint author), Ball Aerosp Syst Div, Fairborn, OH 45324 USA. EM jrchambers@cox.net; r.m.hall@larc.nasa.gov NR 65 TC 23 Z9 27 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 MAY-JUN PY 2004 VL 41 IS 3 BP 436 EP 447 DI 10.2514/1.4470 PG 12 WC Engineering, Aerospace SC Engineering GA 828OC UT WOS:000221981600002 ER PT J AU Capone, FJ Hall, RM Owens, DB Lamar, JE McMillin, SN AF Capone, FJ Hall, RM Owens, DB Lamar, JE McMillin, SN TI Review and recommended experimental procedures for evaluation of Abrupt-Wing-Stall characteristics SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Capone, FJ (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 11 TC 8 Z9 8 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2004 VL 41 IS 3 BP 448 EP 455 DI 10.2514/1.2768 PG 8 WC Engineering, Aerospace SC Engineering GA 828OC UT WOS:000221981600003 ER PT J AU Capone, FJ Owens, DB Hall, RM AF Capone, FJ Owens, DB Hall, RM TI Development of a transonic free-to-roll test capability SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut AB As part of the NASA/Navy Abrupt Wing Stall Program, a relatively low-cost, rapid-access, free-to-roll test rig was developed on which conventional high-strength wind-tunnel models can be used to evaluate both transonic performance and wing-drop/rock behavior in a single tunnel entry. The overall objective was to demonstrate the utility of the free-to-roll test technique as a tool for identifying areas of significant uncommanded lateral activity during ground testing and for gaining insight into the wing-drop/rock behavior of military aircraft at transonic conditions. A description of the test hardware as well as a description of the experimental procedures is given. The free-to-roll test rig has been used successfully to assess the static and dynamic characteristics of four different configurations-two configurations that exhibited uncommanded lateral motions inflight (preproduction F/A-18E and AV-8B) and two that did not (F/A-18C, F-16C). Excellent agreement between free-to-roll results and flight was obtained for those configurations where flight data were available. C1 NASA, Langley Res Ctr, Configurat Aerodynam Branch, Hampton, VA 23681 USA. RP Capone, FJ (reprint author), NASA, Langley Res Ctr, Configurat Aerodynam Branch, Hampton, VA 23681 USA. NR 19 TC 13 Z9 14 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2004 VL 41 IS 3 BP 456 EP 463 DI 10.2514/1.1449 PG 8 WC Engineering, Aerospace SC Engineering GA 828OC UT WOS:000221981600004 ER PT J AU Lamar, JE Hall, RM Capone, FJ McMillin, SN AF Lamar, JE Hall, RM Capone, FJ McMillin, SN TI Usefulness of transonic model static data in predicting flight Abrupt-Wing-Stall SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut AB An approach is provided to answer the question of whether one can rely solely on static data taken during a transonic model test to provide the certainty needed that a new aircraft will or will not have abrupt wing stall (AWS) events during its flight operations. By the comparison of traditional static figures of merit (FOMs) with the free-to-roll (FTR) response data, a rational basis for assessing the merits of using standard testing techniques for the prediction of AWS events has been established. With use of the FTR response data as a standard, because these results compare well with flight, it is concluded that traditional FOMs can not be trusted to provide an indication as to whether a configuration will or will not have AWS tendencies. Even though these FOMs may flag features that have a high degree of correlation with the FTR response data, there are as many or more of these FOM flagged features that do not correlate. Thus, one needs to use the FTR rig to assess AWS tendencies on new configurations. C1 NASA, Langley Res Ctr, Configurat Aerodynam Branch, Hampton, VA 23681 USA. RP Lamar, JE (reprint author), NASA, Langley Res Ctr, Configurat Aerodynam Branch, Hampton, VA 23681 USA. NR 15 TC 2 Z9 2 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2004 VL 41 IS 3 BP 464 EP 473 DI 10.2514/1.2770 PG 10 WC Engineering, Aerospace SC Engineering GA 828OC UT WOS:000221981600005 ER PT J AU Owens, DB Capone, FJ Hall, RM Brandon, JM Chambers, JR AF Owens, DB Capone, FJ Hall, RM Brandon, JM Chambers, JR TI Transonic free-to-roll analysis of abrupt wing stall on military aircraft SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut AB Transonic free-to-roll and static wind-tunnel tests for four military aircraft-the AV-8B, the F/A-18C, the preproduction F/A-18E, and the F-16C-have been analyzed. These tests were conducted in the NASA Langley 16-Foot Transonic Tunnel as a part of the NASA/Navy/Air Force Abrupt Wing Stall Program. The objectives were to evaluate the utility of the free-to-roll test technique as a tool for predicting areas of significant uncommanded lateral motions and for gaining insight into the wing-drop and wing-rock behavior of military aircraft at transonic conditions. The analysis indicated that the free-to-roll results agreed well with flight data on all four models. A wide range of motions-limit-cycle wing rock, occasional and frequent damped wing drop/rock and wing-rock divergence-were observed. The analysis shows the effects that static and dynamic lateral stability can have on the wing-drop/rock behavior. In addition, a free-to-roll figure of merit was developed to assist in the interpretation of results and assessment of the severity of the motions. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Ball Aerosp Syst Div, Fairborn, OH 45324 USA. RP Owens, DB (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 31 TC 7 Z9 9 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 MAY-JUN PY 2004 VL 41 IS 3 BP 474 EP 484 DI 10.2514/1.3073 PG 11 WC Engineering, Aerospace SC Engineering GA 828OC UT WOS:000221981600006 ER PT J AU Schuster, DM Byrd, JE AF Schuster, DM Byrd, JE TI Transonic unsteady aerodynamics of the F/A-18E under conditions promoting abrupt wing stall SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut AB A transonic wind-tunnel test of an 8% F/A-18E model was conducted in the NASA Langley Research Center 16-Foot Transonic Tunnel to investigate the abrupt wing stall characteristics of this aircraft. During this test, both steady and unsteady measurements of balance loads, wing surface pressures, wing-root bending moments, and outer-wing accelerations were performed. The test was conducted with a wide range of model configurations and test conditions in an attempt to reproduce behavior indicative of the abrupt wing stall phenomenon experienced in full-scale aircraft during flight tests. This study focuses on the analysis of the unsteady data acquired during this test. Though the test apparatus was designed to be effectively rigid, model motions due to sting and balance flexibility were observed during the testing, particularly when the tunnel was operated under conditions representative of those where wing drop was experienced in flight. The correlation between observed aerodynamic frequencies and model structural frequencies is analyzed and presented. Significant shock motion and separated How are observed as the aircraft pitches through the abrupt wing stall region. A shock-tracking strategy has been formulated to observe this phenomenon. Using this technique, the range of shock motion as the aircraft encounters abrupt wing stall conditions is readily determined. Spectral analysis of the shock motion shows the frequencies at which the shock oscillates in the abrupt wing stall region, and probability density function analysis of the shock location shows the propensity of the shock to take on a bistable and even tristable character in the abrupt wing stall flight regime. C1 NASA, Langley Res Ctr, Aeroelast Branch, Hampton, VA 23681 USA. Lockheed Martin Engn & Sci, Hampton, VA 23681 USA. RP Schuster, DM (reprint author), NASA, Langley Res Ctr, Aeroelast Branch, MS 340, Hampton, VA 23681 USA. EM schuster@nasa.gov; j.e.byrd@larc.nasa.gov NR 10 TC 13 Z9 13 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2004 VL 41 IS 3 BP 485 EP 492 DI 10.2514/1.4305 PG 8 WC Engineering, Aerospace SC Engineering GA 828OC UT WOS:000221981600007 ER PT J AU Jackson, KE Fasanella, EL AF Jackson, KE Fasanella, EL TI NASA Langley Research Center Impact Dynamics Research Facility research survey SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 44th Structures, Structural Dynamics and Materials Conference CY APR 07-10, 2003 CL NORFOLK, VA SP AIAA, ASME, ASCE, AHS, ASC ID COMPOSITE FUSELAGE CONCEPT; SIMULATION; HELICOPTER; MODEL C1 NASA, USA, Res Lab, Langley Res Ctr,Vehicle Technol Directorate, Hampton, VA 23681 USA. RP Jackson, KE (reprint author), NASA, USA, Res Lab, Langley Res Ctr,Vehicle Technol Directorate, Mail Stop 495, Hampton, VA 23681 USA. NR 77 TC 4 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 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2004 VL 41 IS 3 BP 511 EP 522 DI 10.2514/1.3082 PG 12 WC Engineering, Aerospace SC Engineering GA 828OC UT WOS:000221981600009 ER PT J AU Martins, JRRA Alonso, JJ Reuther, JJ AF Martins, JRRA Alonso, JJ Reuther, JJ TI High-fidelity aerostructural design optimization of a supersonic business jet SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC/SDM 43rd Structures, Structural Dynamics, and Materials Conference CY APR 22-25, 2002 CL DENVER, CO SP AIAA, ASME, ASCE, AHS, ASC ID SENSITIVITY ANALYSIS; ADJOINT FORMULATION; PARALLEL COMPUTERS; SYSTEMS AB This paper focuses on the demonstration of an integrated aerostructural method for the design of aerospace vehicles. Both aerodynamics and structures are represented using high-fidelity models such as the Enter equations for the aerodynamics and a detailed finite element model for the primary structure. The aerodynamic outer-mold line and a structure of fixed topology are parameterized using a large number of design variables. The aerostructural sensitivities of aerodynamic and structural cost functions with respect to both outer-mold line shape and structural variables are computed using an accurate and efficient coupled-adjoint procedure. Kreisselmeier-Steinhauser functions are used to reduce the number of structural constraints in the problem. Results of the aerodynamic shape and structural optimization of a natural laminar-flow supersonic business jet are presented together with an assessment of the accuracy of the sensitivity information obtained using the coupled-adjoint procedure. C1 Univ Toronto, Inst Aerosp Studies, Toronto, ON M3H 5T6, Canada. Stanford Univ, Stanford, CA 94305 USA. NASA, Ames Res Ctr, Moffett Field, CA 95035 USA. RP Martins, JRRA (reprint author), Univ Toronto, Inst Aerosp Studies, Toronto, ON M3H 5T6, Canada. RI Martins, Joaquim/P-3933-2014 OI Martins, Joaquim/0000-0003-2143-1478 NR 23 TC 56 Z9 57 U1 6 U2 16 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2004 VL 41 IS 3 BP 523 EP 530 DI 10.2514/1.11478 PG 8 WC Engineering, Aerospace SC Engineering GA 828OC UT WOS:000221981600010 ER PT J AU Woodard, SE Coffey, NC Gonzalez, GA Taylor, BD Brett, RR Woodman, KL Weathered, BW Rollins, CH AF Woodard, SE Coffey, NC Gonzalez, GA Taylor, BD Brett, RR Woodman, KL Weathered, BW Rollins, CH TI Development and flight testing of an adaptable vehicle health-monitoring architecture SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA Aircraft Technology, Integration, and Operations Technical Forum (ATIO 2002) CY OCT 01, 2002 CL Los Angeles, CA AB Development and testing of an adaptable vehicle health-monitoring architecture is presented. The architecture is being developed for a fleet of vehicles. It has three operational levels: one or more remote data acquisition units located throughout a vehicle, a command and control unit located within a vehicle, and a terminal collection unit to collect analysis results from all vehicles. Each level is capable of performing autonomous analysis with a trained expert system. The expert system is parameterized, which makes it adaptable to be trained to both a user's subjective reasoning and existing quantitative analytic tools. Communication between all levels is done with wireless radio frequency interfaces. The remote data acquisition unit has an eight-channel programmable digital interface that allows the user discretion for choosing type of sensors, number of sensors, sensor sampling rate, and sampling duration for each sensor. The architecture provides framework for a tributary analysis. All measurements at the lowest operational level are reduced to provide analysis results necessary to gauge changes from established baselines. These are then collected at the next level to identify any global trends or common features from the prior level. This process is repeated until the results are reduced at the highest operational level. In the framework, only analysis results are forwarded to the next level to reduce telemetry congestion. The system's remote data acquisition hardware and nonanalysis software have been flight tested on the NASA Langley Research Center's B757 main landing gear to validate the wireless radio frequency communication capabilities of the system, the hardware design, command and control, software operation, and, data acquisition, storage, and retrieval. C1 NASA, Langley Res Ctr, Struct Dynam Branch, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Flight Software Syst Branch, Hampton, VA 23681 USA. Swales Corp, Hampton, VA 23681 USA. Zin Corp, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Lead Airworthiness & Configurat Management Off, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Syst Integrat & Test Branch, Hampton, VA 23681 USA. RP Woodard, SE (reprint author), NASA, Langley Res Ctr, Struct Dynam Branch, Hampton, VA 23681 USA. EM s.e.woodard@larc.nasa.gov; n.c.coffey@larc.nasa.gov NR 5 TC 2 Z9 2 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 MAY-JUN PY 2004 VL 41 IS 3 BP 531 EP 539 DI 10.2514/1.979 PG 9 WC Engineering, Aerospace SC Engineering GA 828OC UT WOS:000221981600011 ER PT J AU Guruswamy, GP Obayashi, S AF Guruswamy, GP Obayashi, S TI Study on the use of high-fidelity methods in aeroelastic optimization SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA/ISSMO 9th Symposium on Multidisciplinary Analysis and Optimization CY SEP 04-06, 2002 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ISSMO AB Multidiciplinary optimization is a key element of the design process. To date multidisciplinary optimization methods that use low-fidelity methods are well developed. Gradient-based optimization methods that use data from three-dimensional linear aerodynamic solvers and two-dimensional structural solvers have been applied to complex aerospace configurations. However, use of high-fidelity methods such as Euler/Navier-Stokes methods for fluids and three-dimensional finite element method for structures is not as well developed. As an activity of the Multidisciplinary Design Optimization Technical Committee (MDO TC) of AIAA, an effort was initiated to assess the status and use of high-fidelity methods in multidisciplinary optimization. Contributions were solicited through the members of the MDO TC. This paper provides a summary of that effort. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Tohoku Univ, Sendai, Miyagi 9808579, Japan. RP Guruswamy, GP (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 24 TC 7 Z9 8 U1 2 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2004 VL 41 IS 3 BP 616 EP 619 DI 10.2514/1.843 PG 4 WC Engineering, Aerospace SC Engineering GA 828OC UT WOS:000221981600022 ER PT J AU Sekula, MK Gandhi, F AF Sekula, MK Gandhi, F TI Effects of auxiliary lift and propulsion on helicopter vibration reduction and trim SO JOURNAL OF AIRCRAFT LA English DT Article AB This paper examines the vibration reductions caused by the introduction of auxiliary lift and propulsion, individually. as well as in combination, on a light [5800-lb (2640 kg)] helicopter with a four-bladed hingeless rotor, at flight speeds close to the maximum cruise velocity of the baseline helicopter. The changes in trim (vehicle orientations and control settings) because of auxiliary lift and propulsion are also examined in detail, and the fundamental mechanisms that produce the changes in trim and associated vibration reductions are identified. Based on results using a comprehensive aeroelastic analysis, it was concluded that auxiliary lift, alone, produces relatively small reductions in vibration. On the other hand, significant vibration reductions were obtained through auxiliary propulsion alone. A combination of lift and propulsion was most effective and reduced the vibration index by over 90%. It was also observed that auxiliary lift significantly reduces the main rotor thrust but increases the nose-down pitch attitude and tip-path-plane forward tilt to provide the required propulsive force. This increases the downwash through the rotor disk and requires a larger rotor longitudinal cyclic pitch input. In contrast, auxiliary propulsion that minimizes vibration produces little reduction in main rotor thrust, but results in a slightly nose-up pitch attitude (the auxiliary propulsion exceeds vehicle drag) along with a backward tilt of the tip-path plane. This decreases the downwash through the rotor disk and requires a smaller rotor longitudinal cyclic pitch input. A combination of auxiliary lift and propulsion minimizes vibration results in an even larger backward tilt of the tip-path plane and a net upwash through the rotor disk. The rotor collective pitch undergoes little change as a result of auxiliary lift, even though the main rotor thrust is decreased. In contrast, for auxiliary propulsion it decreases significantly even though the rotor thrust undergoes only small reductions. This counterintuitive observation is explained. The reduced downwash with auxiliary propulsion, or upwash with combined lift and propulsion, puts the rotor in a partial autorotation state, drastically reducing the induced drag, main rotor torque, and power. Auxiliary lift produces modest reductions in main rotor power, primarily because of a reduced profile drag associated with lower rotor loading. Because the rotor loading is lower with auxiliary lift than with auxiliary propulsion, but larger vibration reductions are produced with the latter, it can be deduced that vibration reductions are less a result of "unloading" of the rotor per se and more because of overall changes in trim, especially the reduction in longitudinal cyclic pitch (seen with auxiliary propulsion). C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Penn State Univ, University Pk, PA 16802 USA. RP Sekula, MK (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 17 TC 3 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 MAY-JUN PY 2004 VL 41 IS 3 BP 645 EP 656 DI 10.2514/1.496 PG 12 WC Engineering, Aerospace SC Engineering GA 828OC UT WOS:000221981600026 ER PT J AU Huang, HL Smith, WL Li, J Antonelli, P Wu, XQ Knuteson, RO Huang, BM Osborne, BJ AF Huang, HL Smith, WL Li, J Antonelli, P Wu, XQ Knuteson, RO Huang, BM Osborne, BJ TI Minimum local emissivity variance retrieval of cloud altitude and effective spectral emissivity - Simulation and initial verification SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID PARAMETERS; AIRBORNE; SATELLITES; AIRCRAFT AB This paper describes the theory and application of the minimum local emissivity variance (MLEV) technique for simultaneous retrieval of cloud pressure level and effective spectral emissivity from high-spectral-resolution radiances, for the case of single-layer clouds. This technique, which has become feasible only with the recent development of high-spectral-resolution satellite and airborne instruments, is shown to provide reliable cloud spectral emissivity and pressure level under a wide range of atmospheric conditions. The MLEV algorithm uses a physical approach in which the local variances of spectral cloud emissivity are calculated for a number of assumed or first-guess cloud pressure levels. The optimal solution for the single-layer cloud emissivity spectrum is that having the "minimum local emissivity variance'' among the retrieved emissivity spectra associated with different first-guess cloud pressure levels. This is due to the fact that the absorption, reflection, and scattering processes of clouds exhibit relatively limited localized spectral emissivity structure in the infrared 10-15-mum longwave region. In this simulation study it is shown that the MLEV cloud pressure root-mean-square errors for a single level with effective cloud emissivity greater than 0.1 are similar to30, similar to10, and similar to50 hPa, for high (200-300 hPa), middle ( 500 hPa), and low (850 hPa) clouds, respectively. The associated cloud emissivity root-mean-square errors in the 900 cm(-1) spectral channel are less than 0.05, 0.04, and 0.25 for high, middle, and low clouds, respectively. C1 Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53706 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. NOAA, NESDIS, Off Res & Applicat, Camp Springs, MD USA. RP Huang, HL (reprint author), Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, 1225 W Dayton St, Madison, WI 53706 USA. EM allenh@ssec.wisc.edu RI Wu, Xiangqian/F-5634-2010; Li, Jun/H-3579-2015 OI Wu, Xiangqian/0000-0002-7804-5650; Li, Jun/0000-0001-5504-9627 NR 13 TC 20 Z9 24 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD MAY PY 2004 VL 43 IS 5 BP 795 EP 809 DI 10.1175/2090.1 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 826JK UT WOS:000221825200012 ER PT J AU Riishojgaard, LP Atlas, R Emmitt, GD AF Riishojgaard, LP Atlas, R Emmitt, GD TI The impact of Doppler lidar wind observations on a single-level meteorological analysis SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article AB Through the use of observation operators, modern data assimilation systems have the capability to ingest observations of quantities that are not themselves model variables but are mathematically related to those variables. An example of this is the so-called line-of-sight (LOS) winds that a spaceborne Doppler wind lidar (DWL) instrument would provide. The model or data assimilation system ideally would need information about both components of the horizontal wind vectors, whereas the observations in this case would provide only the projection of the wind vector onto a given direction. The estimated or analyzed value is then calculated essentially as a weighted average of the observation itself and the model-simulated value of the observed quantity. To assess the expected impact of a DWL, it is important to examine the extent to which a meteorological analysis can be constrained by the LOS winds. The answer to this question depends on the fundamental character of the atmospheric flow fields that are analyzed, but, just as important, it also depends on the real and assumed error covariance characteristics of these fields. A single-level wind analysis system designed to explore these issues has been built at the NASA Data Assimilation Office. In this system, simulated wind observations can be evaluated in terms of their impact on the analysis quality under various assumptions about their spatial distribution and error characteristics and about the error covariance of the background fields. The basic design of the system and experimental results obtained with it are presented. The experiments were designed to illustrate how such a system may be used in the instrument concept definition phase. 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, Data Assimilat Off, Greenbelt, MD 20771 USA. EM larspr@gmao.gsfc.nasa.gov RI Atlas, Robert/A-5963-2011 OI Atlas, Robert/0000-0002-0706-3560 NR 12 TC 15 Z9 15 U1 1 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD MAY PY 2004 VL 43 IS 5 BP 810 EP 820 DI 10.1175/2091.1 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 826JK UT WOS:000221825200013 ER PT J AU Grenon, SM Hurwitz, S Sheynberg, N Xiao, X Ramsdell, CD Mai, CL Kim, C Cohen, RJ Williams, GH AF Grenon, SM Hurwitz, S Sheynberg, N Xiao, X Ramsdell, CD Mai, CL Kim, C Cohen, RJ Williams, GH TI Role of individual predisposition in orthostatic intolerance before and after simulated microgravity SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE cardiovascular deconditioning; renin-angiotensin-aldosterone system; leg venous compliance; autonomic function; head-down-tilt bed rest ID DOWN BED REST; SHORT-DURATION SPACEFLIGHT; CARDIOVASCULAR REGULATION; BAROREFLEX RESPONSES; TACHYCARDIA SYNDROME; 4-DAY CONFINEMENT; VENOUS COMPLIANCE; NERVOUS-SYSTEM; BLOOD-PRESSURE; PLASMA-RENIN AB Orthostatic intolerance (OI) is a major problem after spaceflight. Its etiology remains uncertain, but reports have pointed toward an individual susceptibility to OI. We hypothesized that individual predisposition plays an important role in post-bed rest OI. Twenty-four healthy male subjects were equilibrated on a constant diet, after which they underwent tilt-stand test (pre-TST). They then completed 14 - 16 days of head-down-tilt bed rest, and 14 of the subjects underwent repeat tilt-stand test (post-TST). During various phases, the following were performed: 24-h urine collections and hormonal measurements, plethysmography, and cardiovascular system identification ( a noninvasive method to assess autonomic function and separately quantify parasympathetic and sympathetic responsiveness). Development of presyncope or syncope defined OI. During pre-TST, 11 subjects were intolerant and 13 were tolerant. At baseline, intolerant subjects had lower serum aldosterone ( P < 0.01), higher excretion of potassium ( P = 0.01), lower leg venous compliance ( P = 0.03), higher supine parasympathetic responsiveness ( P = 0.02), and lower standing sympathetic responsiveness ( P = 0.048). Of the 14 subjects who completed post-TST, 9 were intolerant and 5 were tolerant. Intolerant subjects had lower baseline serum cortisol ( P = 0.03) and a higher sodium level ( P = 0.02) compared with tolerant subjects. Thus several physiological characteristics were associated with increased susceptibility to OI. We propose a new model for OI, whereby individuals with greater leg venous compliance recruit compensatory mechanisms ( activation of the renin-angiotensin-aldosterone system and sympathetic nervous system, and withdrawal of the parasympathetic nervous system) in the face of daily postural challenges, which places them at an advantage to face orthostatic stress. With head-down-tilt bed rest, the stimulus to recruit compensatory mechanisms disappears, and differences between the two subgroups attenuate. C1 Brigham & Womens Hosp, Div Endocrinol Hypertens & Diabet, Boston, MA 02115 USA. MIT, Harvard MIT Div Hlth Sci & Technol, NASA, Ctr Quantitat Cardiovasc Physiol Modeling & Data, Cambridge, MA 02139 USA. McGill Univ, Dept Cardiothorac Surg, Montreal, PQ H3G 1A4, Canada. RP Williams, GH (reprint author), Brigham & Womens Hosp, Div Endocrinol Hypertens & Diabet, 221 Longwood Ave, Boston, MA 02115 USA. EM gwilliams@partners.org FU NCRR NIH HHS [5M01 RR-02635] NR 64 TC 11 Z9 11 U1 0 U2 1 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD MAY 1 PY 2004 VL 96 IS 5 BP 1714 EP 1722 DI 10.1152/japplphysiol.01274.2003 PG 9 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA 810XM UT WOS:000220737000018 PM 15075309 ER PT J AU Gupta, SK Kratz, DP Wilber, AC Nguyen, LC AF Gupta, SK Kratz, DP Wilber, AC Nguyen, LC TI Validation of parameterized algorithms used to derive TRMM-CERES surface radiative fluxes SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID SOLAR-RADIATION; SATELLITE DATA; ATMOSPHERIC RADIATION; CLOUD; CLIMATOLOGY; NETWORK; MODEL AB Parameterized shortwave and longwave algorithms developed at the Langley Research Center have been used to derive surface radiative fluxes in the processing of the Clouds and the Earth's Radiant Energy System (CERES) data obtained from flight aboard the Tropical Rainfall Measuring Mission (TRMM) satellite. Retrieved fluxes were validated on an instantaneous-footprint basis using coincident surface measurements obtained from the Atmospheric Radiation Measurement ( ARM) program's Southern Great Plains (SGP) central facility, the ARM/SGP network of extended facilities, and a number of surface sites of the Baseline Surface Radiation Network (BSRN) and the Climate Monitoring and Diagnostics Laboratory (CMDL). Validation was carried out separately for clear-sky and all-sky conditions. For the shortwave, systematic errors varied from 212 to 10 W m(-2) for clear skies and from 25 to 35 W m(-2) for all-sky conditions. Random errors varied from 20 to 40 W m(-2) for clear skies but were much larger (45-85 W m(-2)) for all-sky conditions. For the longwave, systematic errors were comparatively small for both clear-sky and all-sky conditions (0 to -10 W m(-2)) and random errors were within about 20 W m(-2). In general, comparisons with surface data from the ARM/SGP site (especially the central facility) showed the best agreement. Large systematic errors in shortwave comparisons for some sites were related to flaws in the surface measurements. Larger errors in longwave fluxes for some footprints were found to be related to the errors in cloud mask retrievals, mostly during the nighttime. Smaller longwave errors related to potential errors in the operational analysis products used in satellite retrievals were also found. Still, longwave fluxes obtained with the present algorithm nearly meet the accuracy requirements for climate research. C1 Analyt Serv & Mat Inc, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Sci Applicat Int Corp, Hampton, VA USA. RP Gupta, SK (reprint author), Analyt Serv & Mat Inc, 1 Enterprise Pkwy,Ste 300, Hampton, VA 23666 USA. EM s.k.gupta@larc.nasa.gov NR 33 TC 28 Z9 29 U1 0 U2 1 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 MAY PY 2004 VL 21 IS 5 BP 742 EP 752 DI 10.1175/1520-0426(2004)021<0742:VOPAUT>2.0.CO;2 PG 11 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 819NV UT WOS:000221322800003 ER PT J AU Ward, JG Merceret, FJ AF Ward, JG Merceret, FJ TI An automated cloud-edge detection algorithm using cloud physics and radar data SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article AB An automated cloud-edge detection algorithm was developed and extensively tested. The algorithm uses in situ cloud physics data measured by a research aircraft coupled with ground-based weather radar measurements to determine whether the aircraft is in or out of cloud. Cloud edges are determined when the in/out state changes, subject to a hysteresis constraint. The hysteresis constraint prevents isolated transient cloud puffs or data dropouts from being identified as cloud boundaries. The algorithm was verified by detailed manual examination of the dataset in comparison to the results from application of the automated algorithm. C1 NASA, YA D, Kennedy Space Ctr, FL 32899 USA. RP Merceret, FJ (reprint author), NASA, YA D, Kennedy Space Ctr, FL 32899 USA. EM Francis.J.Merceret@nasa.gov NR 8 TC 2 Z9 2 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 MAY PY 2004 VL 21 IS 5 BP 762 EP 765 DI 10.1175/1520-0426(2004)021<0762:AACDAU>2.0.CO;2 PG 4 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 819NV UT WOS:000221322800005 ER PT J AU Ferguson, FT Nuth, JA Johnson, NM AF Ferguson, FT Nuth, JA Johnson, NM TI Thermogravimetric measurement of the vapor pressure of iron from 1573 K to 1973 K SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID COPPER AB The vapor-pressure data of iron was measured using the combination of a Knudsen effusion cell and a high-temperature, thermogravimetric balance. Most of the available vapor-pressure data for iron have been taken below 1600 K. In contrast, the current data have been collected from 1573 to 1973 K, and these values should help fill a void in the data near the melting point of iron. Although the measured vapor pressures have a similar temperature dependence as literature values of iron vapor-pressure data, the current data is consistently lower than these previous values by roughly a factor of 2. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Catholic Univ Amer, Dept Chem, Washington, DC 20064 USA. RP Ferguson, FT (reprint author), NASA, Goddard Space Flight Ctr, Code 691, Greenbelt, MD 20771 USA. EM frank.ferguson@gsfc.nasa.gov RI Ferguson, Frank/C-9493-2012; Johnson, Natasha/E-3093-2012; Nuth, Joseph/E-7085-2012 NR 21 TC 12 Z9 12 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0021-9568 J9 J CHEM ENG DATA JI J. Chem. Eng. Data PD MAY-JUN PY 2004 VL 49 IS 3 BP 497 EP 501 DI 10.1021/je034152w PG 5 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 821TR UT WOS:000221486100022 ER PT J AU Chou, SH Chou, MD Chan, PK Lin, PH Wang, KH AF Chou, SH Chou, MD Chan, PK Lin, PH Wang, KH TI Tropical warm pool surface heat budgets and temperature: Contrasts between 1997/98 El Nino and 1998/99 La Nina SO JOURNAL OF CLIMATE LA English DT Article ID AIR-SEA FLUXES; ATMOSPHERE RESPONSE EXPERIMENT; INDIAN-OCEAN; INDONESIAN THROUGHFLOW; EQUATORIAL PACIFIC; WESTERN PACIFIC; TOGA-COARE; BULK PARAMETERIZATION; DATA SETS; RADIATION AB Seasonal to interannual variations of the net surface heating (F-NET) and its relationship to sea surface temperature tendency (dT(s)/dt) in the tropical eastern Indian and western Pacific Oceans are studied for the period October 1997-September 2000. The surface heat fluxes are derived from the Special Sensor Microwave Imager and Japanese Geostationary Meteorological Satellite radiance measurements. It is found that the magnitude of solar heating is larger than that of evaporative cooling, but the spatial variation of the latter is significantly larger than the former. As a result, the spatial patterns of the seasonal and interannual variability of F-NET are dominated by the variability of evaporative cooling. Seasonal variations of F-NET and dT(s)/dt are significantly correlated, except for the equatorial western Pacific. The high correlation is augmented by the high negative correlation between solar heating and evaporative cooling. The change of F-NET between the 1997/98 El Nino and 1998/99 La Nina is significantly larger in the tropical eastern Indian Ocean than that in the tropical western Pacific. For the former region, reduced evaporative cooling arising from weakened winds during El Nino is generally associated with enhanced solar heating due to reduced cloudiness, leading to enhanced interannual variability of F-NET. For the latter region, reduced evaporative cooling due to weakened winds is generally associated with reduced solar heating arising from increased cloudiness, and vice versa. Consequently, the interannual variability of F-NET is reduced. The correlation between interannual variations of F-NET and dT(s)/dt is weak in the tropical western Pacific and eastern Indian Oceans, indicating the importance of ocean dynamics in affecting the interannual SST variation. C1 Natl Taiwan Univ, Dept Atmospher Sci, Taipei 106, Taiwan. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. Cent Weather Bur, Taipei, Taiwan. RP Chou, SH (reprint author), Natl Taiwan Univ, Dept Atmospher Sci, 1,Sect 4,Roosevelt Rd, Taipei 106, Taiwan. EM shchou@atmos1.as.ntu.edu.tw OI LIN, PO-HSIUNG/0000-0002-6410-6221 NR 48 TC 10 Z9 12 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 MAY PY 2004 VL 17 IS 9 BP 1845 EP 1858 DI 10.1175/1520-0442(2004)017<1845:TWPSHB>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 814BV UT WOS:000220951100008 ER PT J AU Massom, RA Pook, MJ Comiso, JC Adams, N Turner, J Lachlan-Cope, T Gibson, TT AF Massom, RA Pook, MJ Comiso, JC Adams, N Turner, J Lachlan-Cope, T Gibson, TT TI Precipitation over the interior East Antarctic Ice Sheet related to midlatitude blocking-high activity SO JOURNAL OF CLIMATE LA English DT Article ID SURFACE MASS-BALANCE; WINTER SNOW COVER; SEA-ICE; SOUTHERN-HEMISPHERE; BRIGHTNESS TEMPERATURES; ATMOSPHERIC CIRCULATION; TEMPORAL VARIABILITY; REANALYSIS PROJECT; WILKES LAND; WEDDELL SEA AB Intermittent atmospheric blocking-high activity in the South Tasman Sea is shown to play a key role in delivering substantial snowfall as far south as at least 75degreesS on the central East Antarctic Ice Sheet plateau. Typically, cyclones fail to penetrate this far (>1000 km) inland, and accumulation was thought to be dominated by clear-sky precipitation. In East Antarctica, the meridional cloud bands delivering the moisture originate from as far north as 35degrees - 40degreesS, and appear to preferentially pass over the East Antarctic coast in a corridor from similar to120degrees to 160degreesE. Comparison of surface observations, model, and satellite data suggests that a few such episodes contribute a significant proportion of the ( low) mean annual accumulation of the central East Antarctic Ice Sheet (e.g., an estimated 44% at Dome C over 18 days in December 2001 - January 2002). Blocking-high-related incursions also cause abrupt increases in the surface wind speed ( snow redistribution) and air temperature; this has implications for the interpretation of ice core data. Blocking-high-related precipitation episodes can generally be detected over the ice sheet interior, via abrupt changes (of similar to0.02 -0.04) in polarization in 37- and 85-GHz SSM/I data, due to the relative stability of the surface and its "background'' microwave signature and the relative lack of cloud cover overall. This is not the case in high-accumulation near-coastal regions such as Law Dome, where additional information is required. Ambiguities remain due to blowing snow and hoarfrost formation. Further research is necessary to examine the frequency of occurrence and variability of midlatitude blocking-high systems, their effect on precipitation in the Antarctic Ice Sheet interior, and the potential effect of global change. C1 Univ Tasmania, Antarctic Climate & Ecosyst Cooperat Res Ctr, Hobart, Tas 7001, Australia. CSIRO Marine Res, Hobart, Tas, Australia. NASA, Oceans & Ice Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Australian Bur Meteorol, Hobart, Tas, Australia. British Antarctic Survey, Cambridge CB3 0ET, England. Univ Tasmania, Antarctic Cooperat Res Ctr, Hobart, Tas, Australia. RP Massom, RA (reprint author), Univ Tasmania, Antarctic Climate & Ecosyst Cooperat Res Ctr, Private Bag 80, Hobart, Tas 7001, Australia. EM r.massom@utas.edu.au RI Pook, Michael/A-3810-2012 NR 75 TC 37 Z9 40 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 MAY PY 2004 VL 17 IS 10 BP 1914 EP 1928 DI 10.1175/1520-0442(2004)017<1914:POTIEA>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 818VK UT WOS:000221272400002 ER PT J AU Yang, JN Lei, Y Lin, SL Huang, N AF Yang, JN Lei, Y Lin, SL Huang, N TI Identification of natural frequencies and dampings of in situ tall buildings using ambient wind vibration data SO JOURNAL OF ENGINEERING MECHANICS-ASCE LA English DT Article DE data analysis; buildings; high-rise; wind loads; damping ratio; natural frequency ID HILBERT SPECTRUM AB An accurate prediction for the response of tall buildings subject to strong wind gusts or earthquakes requires the information of in situ dynamic properties of the building, including natural frequencies and damping ratios. This paper presents a method of identifying natural frequencies and damping ratios of in situ tall buildings using ambient wind vibration data. Our approach is based on the empirical mode decomposition (EMD) method, the random decrement technique (RDT), and the Hilbert-Huang transform. Our method requires only one acceleration sensor. The noisy measurement of the building acceleration is first processed through the EMD method to determine the response of each mode. Then, RDT is used to obtain the free vibration modal response. Finally, the Hilbert transform is applied to each free vibration modal response to identify natural frequencies and damping ratios of in situ tall buildings. The application of the proposed methodology is demonstrated in detail using simulated response data of a 76-story benchmark building polluted by noise. Both the along-wind and across-wind vibration measurements have been illustrated. Simulation results demonstrate that the accuracy of the proposed method in identifying natural frequencies and damping ratios is remarkable. The methodology proposed herein provides a new and effective tool for the parametric identification of in situ tall buildings. C1 Univ Calif Irvine, Dept Civil & Environm Engn, Irvine, CA 92697 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Yang, JN (reprint author), Univ Calif Irvine, Dept Civil & Environm Engn, Irvine, CA 92697 USA. EM jnyang@uci.edu RI Lei, ying/C-8567-2013 NR 22 TC 52 Z9 58 U1 0 U2 14 PU ASCE-AMER SOC CIVIL ENGINEERS PI RESTON PA 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA SN 0733-9399 J9 J ENG MECH-ASCE JI J. Eng. Mech.-ASCE PD MAY PY 2004 VL 130 IS 5 BP 570 EP 577 DI 10.1061/(ASCE)0733-9399(2004)130:5(570) PG 8 WC Engineering, Mechanical SC Engineering GA 814FL UT WOS:000220960500006 ER PT J AU Lien, MC Ruthruff, E AF Lien, MC Ruthruff, E TI Task switching in a hierarchical task structure: Evidence for the fragility of the task repetition benefit SO JOURNAL OF EXPERIMENTAL PSYCHOLOGY-LEARNING MEMORY AND COGNITION LA English DT Article ID REFRACTORY PERIOD PARADIGM; SIMPLE COGNITIVE TASKS; SET RECONFIGURATION; ATTENTION; INFORMATION; COSTS; PERFORMANCE AB This study examined how task switching is affected by hierarchical task organization. Traditional task-switching studies, which use a constant temporal and spatial distance between each task element (defined as a stimulus requiring a response), promote a flat task structure. Using this approach, Experiment 1 revealed a large switch cost of 238 ms. In Experiments 2-5, adjacent task elements were grouped temporally and/or spatially (forming an ensemble) to create a hierarchical task organization. Results indicate that the effect of switching at the ensemble level dominated the effect of switching at the element level. Experiments 6 and 7, using an ensemble of 3 task elements, revealed that the element-level switch cost was virtually absent between ensembles but was large within an ensemble. The authors conclude that the element-level task repetition benefit is fragile and can be eliminated in a hierarchical task organization. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Lien, MC (reprint author), NASA, Ames Res Ctr, Mail Stop 262-4, Moffett Field, CA 94035 USA. EM mclien@mail.arc.nasa.gov NR 35 TC 32 Z9 32 U1 0 U2 0 PU AMER PSYCHOLOGICAL ASSOC PI WASHINGTON PA 750 FIRST ST NE, WASHINGTON, DC 20002-4242 USA SN 0278-7393 EI 1939-1285 J9 J EXP PSYCHOL LEARN JI J. Exp. Psychol.-Learn. Mem. Cogn. PD MAY PY 2004 VL 30 IS 3 BP 697 EP 713 DI 10.1037/0278-7393.30.3.697 PG 17 WC Psychology; Psychology, Experimental SC Psychology GA 813VR UT WOS:000220935100013 PM 15099137 ER PT J AU Greene, JL Bovell-Benjamin, AC AF Greene, JL Bovell-Benjamin, AC TI Macroscopic and sensory evaluation of bread supplemented with sweet-potato flour SO JOURNAL OF FOOD SCIENCE LA English DT Article DE sweet-potato bread; sweet-potato flour; loaf volume; sensory evaluation ID NUTRITIONAL-EVALUATION; WHEAT-FLOUR; ACCEPTABILITY; COMPOSITE; STORAGE; POWDER; CRUST; DOUGH AB The macroscopic and sensory properties of breads supplemented with 50%, 55%, 60%, and 65% sweetpotato flour were evaluated. Moisture contents of the breads fluctuated during storage. Protein value was highest for the bread supplemented with 50% sweet-potato flour. Carbohydrate contents ranged from 18.2% to 24.4%. beta-carotene contents and loaf volumes were highest in the breads supplemented with 65% and 50% sweet-potato flour, respectively. The breads were similarly firm, with comparable vitamin C contents at the end of storage. The bread with 65% sweet-potato flour had the most intense yellow-orange color. Twelve perceived. sensory attributes, which could be used to differentiate the appearance, texture, and flavor of sweet-potato breads,, were generated. C1 Tuskegee Univ, NASA, Ctr Food & Environm Syst Human Explorat Space, Dept Food Sci & Nutr, Tuskegee, AL 36088 USA. N Carolina State Univ, Raleigh, NC 27695 USA. RP Bovell-Benjamin, AC (reprint author), Tuskegee Univ, NASA, Ctr Food & Environm Syst Human Explorat Space, Dept Food Sci & Nutr, Tuskegee, AL 36088 USA. EM acbenjamin@tusk.edu NR 42 TC 3 Z9 4 U1 0 U2 6 PU INST FOOD TECHNOLOGISTS PI CHICAGO PA 525 WEST VAN BUREN, STE 1000, CHICAGO, IL 60607-3814 USA SN 0022-1147 J9 J FOOD SCI JI J. Food Sci. PD MAY PY 2004 VL 69 IS 4 BP S167 EP S173 PG 7 WC Food Science & Technology SC Food Science & Technology GA 848TG UT WOS:000223489400048 ER PT J AU Bayard, DS AF Bayard, DS TI State-space approach to computing spacecraft pointing jitter SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article; Proceedings Paper CT AIAA Guidance Navigation and Control Conference CY AUG 11-14, 2003 CL Austin, TX SP AIAA ID STABILITY; MATRIX AB Pointing jitter refers to unwanted line-of-sight motion incurred by a pointing system over a time window of specified duration. Jitter acts to smear images and degrade the quality of science obtainable from camera-type instruments. A recent mathematical expression for finite window pointing jitter involves the frequency-domain integral of a rational polynomial multiplied by a transcendental weighting function. Because of its complexity, the expression is generally evaluated using numerical integration. The main contribution of this paper is a state-space method for evaluating the frequency-domain integral. In particular, an exact state-space expression is developed that can be evaluated by computing a matrix exponential and solving a Lyapunov equation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bayard, DS (reprint author), CALTECH, Jet Prop Lab, MS 198-326,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM david.bayard@jpl.nasa.gov NR 21 TC 3 Z9 3 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAY-JUN PY 2004 VL 27 IS 3 BP 426 EP 433 DI 10.2514/1.2783 PG 8 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 820VV UT WOS:000221418600011 ER PT J AU Viegas, SF Williams, D Jones, J Strauss, S Clark, J AF Viegas, SF Williams, D Jones, J Strauss, S Clark, J TI Physical demands and injuries to the upper extremity associated with the space program SO JOURNAL OF HAND SURGERY-AMERICAN VOLUME LA English DT Article DE space program; upper extremity injuries; astronauts AB Hand and upper-extremity overuse and repetitive injuries in astronauts have been and continue to be a common problem in the space program. The demands on upper-extremity use in the astronaut training program, the zero-gravity environment, the extreme temperature conditions of space, the effects of space travel on human physiology/anatomy, and the constraints and pressures of space suits and gloves all can negatively impact upper-extremity function in ways that can result in overuse/repetitive injuries. Future plans for space exploration include endeavors that will continue and even increase the demands on the hand and upper extremity. Copyright (C) 2004 by the American Society for Surgery of the Hand. C1 Dept Orthopaed Surg & Rehabil, Div Hand Surg, Galveston, TX 77555 USA. NASA, Houston, TX USA. Kelsey Seybold Clin, Houston, TX USA. RP Viegas, SF (reprint author), Dept Orthopaed Surg & Rehabil, Div Hand Surg, 301 Univ Blvd, Galveston, TX 77555 USA. NR 6 TC 13 Z9 13 U1 1 U2 2 PU W B SAUNDERS CO PI PHILADELPHIA PA INDEPENDENCE SQUARE WEST CURTIS CENTER, STE 300, PHILADELPHIA, PA 19106-3399 USA SN 0363-5023 J9 J HAND SURG-AM JI J. Hand Surg.-Am. Vol. PD MAY PY 2004 VL 29A IS 3 BP 359 EP 366 DI 10.1016/j.jhsa.2004.01.015 PG 8 WC Orthopedics; Surgery SC Orthopedics; Surgery GA 822QO UT WOS:000221555100002 PM 15140472 ER PT J AU Hoffmann, JA Penanen, K Davis, JC Packard, RE AF Hoffmann, JA Penanen, K Davis, JC Packard, RE TI Measurements of attenuation of third sound: Evidence of trapped vorticity in thick films of superfluid He-4 SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article DE third sound; helium film; quantized vortices ID LIQUID HELIUM FILMS; THIRD SOUND; UNCERTAINTY PRINCIPLE; 3RD-SOUND RESONATOR; HYDRODYNAMICS; RESONANCES AB We present results of a study of third sound in thick He-4 films in circular resonator geometry. Frequency and line shapes of third sound resonances are measured for temperatures between 0.3 and 2.1 K in saturated films approximately 30 nm thick. From these measurements we calculate the attenuation of the sound. We find that the attenuation at a given temperature is a function of history of the film, strongly affected by such events as large, sudden ( more than milli-Kelvin per second) temperature spikes. We also observe variable frequency splitting of resonances, indicating trapped circulation. Our measurements, taken together with other reported attenuation experiments, are incompatible with dissipation mechanisms dependent on thermodynamic properties alone. Measurements indicate a linear dissipation mechanism, inconsistent with vortex drag and re-connection models. We conclude that high attenuation values, evidence of trapped circulation, and variation in attenuation values support the hypothesis that thick films of 4He contain high densities of remnant quantized vortices. The vortex populations suggested by trapped circulation are consistent with proposed linear dissipation mechanisms due to vortex-normal fluid interactions and vortex dimple drag. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Cornell Univ, Dept Phys, LASSP, Ithaca, NY 14853 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hoffmann, JA (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. EM joaner@socrates.berkeley.edu NR 29 TC 3 Z9 3 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD MAY PY 2004 VL 135 IS 3-4 BP 177 EP 202 DI 10.1023/B:JOLT.0000024548.03525.cd PG 26 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 813TB UT WOS:000220928300001 ER PT J AU Wang, TS Droege, A D'Agostino, M Lee, YC Williams, R AF Wang, TS Droege, A D'Agostino, M Lee, YC Williams, R TI Asymmetric base-bleed effect on aerospike plume-induced base-heating environment SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID CLUSTERED NOZZLE CONFIGURATION; FLOWFIELD AB A computational heat transfer design methodology was developed to study the dual-engine linear aerospike plume-induced base-heating environment during one power-pack out, in ascent flight. It includes a three-dimensional, finite volume, viscous, chemically reacting, and pressure-based computational fluid dynamics formulation, a special base-bleed boundary condition, and a three-dimensional, finite volume, and spectral-line-based weighted-sum-of-gray-gases absorption computational radiation heat transfer formulation. A separate radiation model was used for diagnostic purposes. The computational methodology was systematically benchmarked. In this study, near-base radiative heat fluxes were computed, and they compared well with those measured during static linear aerospike engine tests. The base-heating environment of 18 trajectory points selected from three power-pack out scenarios was computed. The computed asymmetric base-heating physics were analyzed. The power-pack out condition has the most impact on convective base heating when it happens early in flight. The source of its impact comes from the asymmetric and reduced base bleed. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Wang, TS (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 23 TC 14 Z9 14 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2004 VL 20 IS 3 BP 385 EP 393 DI 10.2514/1.10385 PG 9 WC Engineering, Aerospace SC Engineering GA 820VW UT WOS:000221418700001 ER PT J AU Lin, CS Van Dresar, NT Hasan, MM AF Lin, CS Van Dresar, NT Hasan, MM TI Pressure control analysis of cryogenic storage systems SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB This paper examines self-pressurization of cryogenic storage tanks due to heat leakage through the thermal protection system and the performance of various pressure control technologies intended for application in microgravity environments. Methods of pressure control such as fluid mixing, passive thermodynamic venting, and active thermodynamic venting are analyzed using the homogeneous thermodynamic model. The homogeneous model assumes that the liquid and vapor phases are at a uniform temperature equal to the saturation temperature of the cryogenic fluid at the total tank pressure. Simplified equations suggested in the paper may be used to characterize the performance of various pressure-control systems and to design space experiments for the development of low-gravity cryogenic fluid management technologies. C1 Analex Corp, Brookpark, OH 44142 USA. NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Lin, CS (reprint author), Analex Corp, Brookpark, OH 44142 USA. NR 11 TC 5 Z9 8 U1 0 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2004 VL 20 IS 3 BP 480 EP 485 DI 10.2514/1.10387 PG 6 WC Engineering, Aerospace SC Engineering GA 820VW UT WOS:000221418700011 ER PT J AU Dorney, DJ Griffin, LW Sondak, DL AF Dorney, DJ Griffin, LW Sondak, DL TI Full- and partial-admission performance of the simplex turbine SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID SUPERSONIC TURBINE; UNSTEADY-FLOW AB The turbines used in rocket-engine applications are often partial-admission turbines, meaning that the flow enters the rotor over only a portion of the annulus. These turbines have been traditionally analyzed, however, assuming full-admission characteristics. This assumption enables the simulation of only a portion of the 360-deg annulus with periodic boundary conditions applied in the circumferential direction. Whereas this traditional approach to simulating the flow in partial-admission turbines significantly reduces the computational requirements, the accuracy of the solutions has not been evaluated or compared to partial-admission data. In the current investigation, both full-admission and partial-admission three-dimensional unsteady Navier-Stokes simulations were performed. for a partial-admission turbine designed and tested at NASA Marshall Space Flight Center. The results indicate that the partial-admission nature of the turbine should be included in simulations to properly predict the performance and flow unsteadiness of the turbine. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Boston Univ, Boston, MA 02215 USA. RP Dorney, DJ (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 11 TC 1 Z9 1 U1 1 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2004 VL 20 IS 3 BP 486 EP 491 DI 10.2514/1.10379 PG 6 WC Engineering, Aerospace SC Engineering GA 820VW UT WOS:000221418700012 ER PT J AU Hunter, CA AF Hunter, CA TI Experimental investigation of separated nozzle flows SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT AIAA/ASME/SAE/ASEE 34th Joint Propulsion Conference and Exhibit CY JUL 12-15, 1998 CL CLEVELAND, OHIO SP Amer Inst Aeronaut & Astronaut, ASME, SAE, ASEE AB A detailed experimental study of separated nozzle flows has been conducted at the NASA Langley Research Center 16-Foot Transonic Tunnel Complex. As part of a comprehensive static performance investigation, force, moment, and pressure measurements were made and schlieren flow visualization was obtained for a subscale, nonaxisymmetric, two-dimensional, convergent-divergent nozzle. For reference, experimental results were compared with theoretical predictions based on one-dimensional gasdynamics and an approximate integral momentum boundary-layer method. Results from this study indicate that overexpanded nozzle flow was dominated by shock-induced boundary-layer separation, which was divided into two distinct flow regimes: three-dimensional separation with partial reattachment and fully detached two-dimensional separation. The test nozzle was observed to go through a marked transition in passing from one regime to the other. In all cases, separation provided a significant increase in static thrust efficiency compared to the ideal prediction. Results suggest that, with controlled separation, the entire overexpanded range of nozzle performance would be within 16% of the peak thrust efficiency. By offering savings in weight and complexity over a conventional mechanical variable geometry exhaust system, a fixed geometry nozzle may be able to cover an entire flight envelope in some applications. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Hunter, CA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM craig.hunter@nasa.gov NR 13 TC 12 Z9 13 U1 1 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2004 VL 20 IS 3 BP 527 EP 532 DI 10.2514/1.4612 PG 6 WC Engineering, Aerospace SC Engineering GA 820VW UT WOS:000221418700017 ER PT J AU Pack-Melton, L Seifert, A AF Pack-Melton, L Seifert, A TI Use of multiple actuators for jet vectoring SO JOURNAL OF PROPULSION AND POWER LA English DT Article C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. Tel Aviv Univ, IL-69978 Tel Aviv, Israel. RP Pack-Melton, L (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. EM l.p.melton@larc.nasa.gov; Seifert@eng.tau.ac.il NR 9 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2004 VL 20 IS 3 BP 572 EP 575 DI 10.2514/1.10389 PG 4 WC Engineering, Aerospace SC Engineering GA 820VW UT WOS:000221418700022 ER PT J AU Pippin, HG Normand, E Woll, SLB Kamenetzky, R AF Pippin, HG Normand, E Woll, SLB Kamenetzky, R TI Analysis of metallized Teflon (TM) thin-film materials performance on satellites SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Laboratory and on-orbit performance data for two common thermal control materials, silver- and aluminum-backed (metallized) fluorinated ethyl-propylene, were collected from a variety of sources and analyzed. It is demonstrated that the change in solar absorptance alpha is a strong function of particulate radiation for these materials. Examination of additional data shows that the atomic-oxygen recession rate is a strong function of solar exposure with an induction period of between 25 to 50 equivalent solar hours. The relationships determined in this analysis were incorporated into an electronic knowledge base, the "Spacecraft Materials Selector," under NASA Contract NAS8-98213. This tool is available from the NASA Space Environments and Effects program office. C1 Boeing Phantom Works, Space & Commun, Seattle, WA 98124 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Pippin, HG (reprint author), Boeing Phantom Works, Space & Commun, POB 3999, Seattle, WA 98124 USA. NR 15 TC 2 Z9 2 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2004 VL 41 IS 3 BP 322 EP 325 DI 10.2514/1.10725 PG 4 WC Engineering, Aerospace SC Engineering GA 830DM UT WOS:000222101800002 ER PT J AU Banks, BA Snyder, A Miller, SK de Groh, KK Demko, R AF Banks, BA Snyder, A Miller, SK de Groh, KK Demko, R TI Atomic-oxygen undercutting of protected polymers in low earth orbit SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Hydrocarbon-based polymers that are exposed to atomic oxygen in low Earth orbit are slowly oxidized into volatile gases, which results in their erosion. Atomic-oxygen protective coatings that are both durable to atomic oxygen and effective in protecting underlying polymers have been developed. However, scratches, pin window defects,. polymer surface roughness, and protective coating layer configuration can result in erosion and potential failure of protected thin polymer films even though the coatings are themselves atomic-oxygen durable. Issues are presented that cause protective coatings to become ineffective in some cases yet effective in others because of the details of their specific application. Observed in-space examples of failed and successfully protected materials using identical protective thin films are discussed and analyzed. Ground laboratory atomic-oxygen testing was conducted and compared with water vapor transport analyses from a previous study of protective coatings on Kapton(R) (polyimide), which indicates that vapor-deposited aluminized films are not as protective as sputter-deposited silicon dioxide films because of a greater number of pin window defects. Computational modeling was conducted and indicates that atomic-oxygen atoms trapped between the front and back surface aluminized films cause accelerated undercutting damage. C1 NASA, John H Glenn Res Ctr Lewis Field, Power & On Board Technol Div, Electrophys Branch, Cleveland, OH 44135 USA. Cleveland State Univ, Cleveland, OH 44115 USA. RP Banks, BA (reprint author), NASA, John H Glenn Res Ctr Lewis Field, Power & On Board Technol Div, Electrophys Branch, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 18 TC 21 Z9 25 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2004 VL 41 IS 3 BP 335 EP 339 DI 10.2514/1.10726 PG 5 WC Engineering, Aerospace SC Engineering GA 830DM UT WOS:000222101800004 ER PT J AU Snyder, A Banks, BA AF Snyder, A Banks, BA TI Fast three-dimensional modeling of atomic-oxygen undercutting of protected polymers SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB A method is presented to model atomic-oxygen erosion of protected polymers in low Earth orbit. Undercutting of protected polymers by atomic oxygen can occur as a result of the presence of scratch, crack, or I pin window defects in the protective coatings. As a means of providing a better understanding of undercutting processes, a fast method of modeling atomic-oxygen undercutting of protected polymers has been developed. Current simulation methods often rely on computationally expensive ray-tracing procedures to track the surface-to-surface movement of individual "atoms." To reduce the burden of time-consuming calculations, the method introduced replaces computationally demanding individual particle simulations by substituting a model that utilize both a geometric configuration-factor technique, which collectively governs the diffuse transport of atoms between surfaces, and an efficient algorithm, which rapidly computes the cumulative effects stemming from the series of atomic-oxygen collisions at the surfaces of an undercut cavity. This new method facilitates the systematic study of three-dimensional undercutting by allowing rapid simulations to be made over a wide range of erosion parameters. C1 NASA, John H Glenn Res Ctr Lewis Field, Power & On Board Technol Div, Electrophys Branch, Cleveland, OH 44135 USA. RP Snyder, A (reprint author), NASA, John H Glenn Res Ctr Lewis Field, Power & On Board Technol Div, Electrophys Branch, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 4 TC 0 Z9 0 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 MAY-JUN PY 2004 VL 41 IS 3 BP 340 EP 344 DI 10.2514/1.13964 PG 5 WC Engineering, Aerospace SC Engineering GA 830DM UT WOS:000222101800005 ER PT J AU de Groh, KK Martin, M AF de Groh, KK Martin, M TI Thermal contributions to the degradation of ground laboratory and space-irradiated Teflon (R) SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID TELESCOPE; FEP AB The aluminized Teflon(R) fluorinated ethylene propylene outermost layer of the multilayer insulation blankets on the Hubble Space Telescope has become embrittled, resulting in severe on-orbit cracking. During the second servicing mission, a piece of aluminized fluorinated ethylene propylene was retrieved. This cracked piece of insulation had curled on-orbit, exposing the backsurface aluminum to space. This extremely embrittled piece reached 200degreesC on orbit, 150degreesC higher than the nominal temperature extreme. Therefore, experiments have been conducted to determine the effect of heating on the degradation of fluorinated ethylene propylene that has been irradiated in a ground laboratory facility or in space on the Hubble Space Telescope. Samples of pristine, x-ray irradiated and Hubble Space Telescope retrieved fluorinated ethylene propylene were heat treated from 50 to 200degreesC at 25degreesC intervals in a high vacuum facility and tensile tested. Density measurements were also obtained. Results indicate that heating does not embrittle nonirradiated Teflon. However, there is a significant dependence of the embrittlement of irradiated Teflon on heating temperature, with near complete loss of elongation at 100degreesC and higher. Rate of degradation changes, which were consistent with the glass transition temperature for fluorinated ethylene propylene, were present in the data. The results support chain scission as the primary mechanism of degradation of fluorinated ethylene propylene on the Hubble Space Telescope and indicate the significance of the on-orbit temperature of fluorinated ethylene propylene with respect to its degradation in the space environment. C1 NASA, John H Glenn Res Ctr Lewis Field, Electrophys Branch, Cleveland, OH 44135 USA. Ohio Aerospace Inst, Brookpark, OH 44142 USA. RP de Groh, KK (reprint author), NASA, John H Glenn Res Ctr Lewis Field, Electrophys Branch, M-S 309-2,21000 Brookpk Rd, Cleveland, OH 44135 USA. EM Kim.K.deGroh@nasa.gov RI Trexler, Morgana/E-9003-2013 NR 16 TC 5 Z9 5 U1 0 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2004 VL 41 IS 3 BP 366 EP 372 DI 10.2514/1.10723 PG 7 WC Engineering, Aerospace SC Engineering GA 830DM UT WOS:000222101800010 ER PT J AU Murman, SM Aftosmis, MJ Berger, MJ AF Murman, SM Aftosmis, MJ Berger, MJ TI Numerical simulation of rolling airframes using a multilevel Cartesian method SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID MESHES AB A supersonic rolling missile with two synchronous canard control surfaces is analyzed using an automated, inviscid, Cartesian method. Sequential-static and time-dependent dynamic simulations of the complete motion are computed for canard dither schedules for level flight, pitch, and yaw maneuvers. The dynamic simulations are compared directly against both high-resolution viscous simulations and relevant experimental data and are also utilized to compute dynamic stability derivatives. The results show that both the body roll rate and canard dither motion influence the roll-averaged forces and moments on the body. At the relatively low roll rates analyzed in the current work these dynamic effects ate modest; however, the dynamic computations are effective in predicting the dynamic stability derivatives, which can be significant for highly maneuverable missiles. C1 ELORET, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Adv Supercomp Div, Moffett Field, CA 94035 USA. Courant Inst, Dept Comp Sci, New York, NY 10012 USA. RP Murman, SM (reprint author), ELORET, Moffett Field, CA 94035 USA. EM smurman@nas.nasa.gov NR 26 TC 2 Z9 3 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 MAY-JUN PY 2004 VL 41 IS 3 BP 426 EP 435 DI 10.2514/1.10697 PG 10 WC Engineering, Aerospace SC Engineering GA 830DM UT WOS:000222101800019 ER PT J AU Zhu, HD Sankart, BV Haftka, RT Venkataraman, S Blosser, M AF Zhu, HD Sankart, BV Haftka, RT Venkataraman, S Blosser, M TI Minimum mass design of insulation made of functionally graded material SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC/SDM 43rd Structures, Structural Dynamics, and Materials Conference CY APR 22-25, 2002 CL DENVER, CO SP AIAA, ASME, ASCE, AHS, ASC C1 Univ Florida, Dept Mech & Aerosp Engn, Gainesville, FL 32611 USA. San Diego State Univ, Dept Aerosp Engn & Engn Mech, San Diego, CA 92182 USA. NASA, Langley Res Ctr, Met & Thermal Struct Branch, Hampton, VA 23681 USA. RP Zhu, HD (reprint author), Univ Florida, Dept Mech & Aerosp Engn, Gainesville, FL 32611 USA. EM sankar@ufl.edu OI Sankar, Bhavani/0000-0002-4556-1982 NR 6 TC 4 Z9 4 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2004 VL 41 IS 3 BP 467 EP 469 DI 10.2514/1.1032 PG 3 WC Engineering, Aerospace SC Engineering GA 830DM UT WOS:000222101800024 ER PT J AU Banerjee, S Mal, AK Prosser, WH AF Banerjee, S Mal, AK Prosser, WH TI Analysis of transient Lamb waves generated by dynamic surface sources in thin composite plates SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID LOADS AB A theoretical analysis is carried out in an effort to understand certain unusual properties of transient guided waves produced in a thin unidirectional graphite/epoxy composite plate by a localized dynamic surface load. The surface motion is calculated using an approximate plate theory, called the shear deformation plate theory (SDPT), as well as a recently developed finite element analysis (FEA), for their mutual verification. The results obtained by the two methods are shown to have excellent agreement. An interesting, nearly periodic "phase reversal" of the signal with propagation distance is observed for each propagation direction relative to the fiber direction. For clarification, a closed form analytical expression for the vertical surface displacement in an aluminum plate to an impulsive point force is obtained using the steepest descent method. It is found that the strong dispersion of the first antisymmetric waves at low frequencies is the main reason behind the phase reversal. This is verified further by measuring the surface response of a relatively thick aluminum plate to a pencil lead break source. The understanding developed in the paper is expected to be helpful in detecting and characterizing the occurrence of damage in composite structures. (C) 2004 Acoustical Society of America. C1 Univ Calif Los Angeles, Dept Mech & Aerosp Engn, Los Angeles, CA 90095 USA. NASA, Langley Res Ctr, Nondestruct Evaluat Branch, Hampton, VA 23681 USA. RP Mal, AK (reprint author), Univ Calif Los Angeles, Dept Mech & Aerosp Engn, Los Angeles, CA 90095 USA. EM ajit@ucla.edu NR 14 TC 19 Z9 19 U1 1 U2 5 PU ACOUSTICAL SOC AMER AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD MAY PY 2004 VL 115 IS 5 BP 1905 EP 1911 DI 10.1121/1.1694993 PN 1 PG 7 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 816TH UT WOS:000221131700008 ER PT J AU Campbell, MR Johnston, SL Marshburn, T Kane, J Lugg, D AF Campbell, MR Johnston, SL Marshburn, T Kane, J Lugg, D TI Nonoperative treatment of suspected appendicitis in remote medical care environments: Implications for future spaceflight medical care SO JOURNAL OF THE AMERICAN COLLEGE OF SURGEONS LA English DT Review ID UNITED-STATES; LAPAROSCOPIC APPENDECTOMY; INCIDENTAL APPENDECTOMY; ABDOMINAL-PAIN; MANAGEMENT; SPACE; WEIGHTLESSNESS; MICROGRAVITY; SURGERY; THERAPY C1 Gen Surg, Paris, France. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. USN, Undersea Med Inst, Groton, CT USA. NASA, Washington, DC 20546 USA. RP Campbell, MR (reprint author), 575 DeShong, Paris, TX 75460 USA. NR 66 TC 31 Z9 31 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 1072-7515 J9 J AM COLL SURGEONS JI J. Am. Coll. Surg. PD MAY PY 2004 VL 198 IS 5 BP 822 EP 830 DI 10.1016/j.jamcollsurg.2004.01.009 PG 9 WC Surgery SC Surgery GA 816XK UT WOS:000221142400016 PM 15110816 ER PT J AU Alexandrov, MD Marshak, A Cairns, B Lacis, AA Carlson, BE AF Alexandrov, MD Marshak, A Cairns, B Lacis, AA Carlson, BE TI Scaling properties of aerosol optical thickness retrieved from ground-based measurements SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ROTATING SHADOWBAND RADIOMETER; LIQUID WATER DISTRIBUTIONS; TRACE GASES PARAMETERS; BOUNDARY-LAYER; MARINE STRATOCUMULUS; ATMOSPHERIC AEROSOLS; DEPTH; INVARIANCE; INSTRUMENT; INTERMITTENCY AB Statistical scale-by-scale analysis, for the first time, has been applied to the aerosol optical thickness (AOT) retrieved from the Multi-Filter Rotating Shadowband Radiometer (MFRSR) network. The MFRSR data were collected in September 2000 from the dense local network operated by the U. S. Department of Energy Atmospheric Radiation Measurement program, located in Oklahoma and Kansas. These data have 20-s temporal resolution. The instrument sites form an irregular grid with the mean distance between neighboring sites about 80 km. It is found that temporal variability of AOT can be separated into two well-established scale-invariant regimes: 1) microscale (0.5 - 15 km), where fluctuations are governed by 3D turbulence, and 2) intermediate scale ( 15 - 100 km), characterized by a transition toward large-scale 2D turbulence. The spatial scaling of AOT was determined by the comparison of retrievals between different instrument sites ( distance range 30 - 400 km). The authors investigate how simultaneous determination of AOT scaling in space and time can provide means to examine the validity of Taylor's frozen turbulence hypothesis. The temporal evolution of AOT scaling exponents during the month appeared to be well correlated with changes in aerosol vertical distribution, while their spatial variability reflects the concavity/ convexity of the site topography. Explanations based on dynamical processes in atmospheric convective boundary layer are suggested. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Appl Phys & Appl Math, New York, NY USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Alexandrov, MD (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM malexandrov@giss.nasa.gov RI Lacis, Andrew/D-4658-2012; Carlson, Barbara/D-8319-2012; Marshak, Alexander/D-5671-2012; OI Cairns, Brian/0000-0002-1980-1022 NR 37 TC 10 Z9 10 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY PY 2004 VL 61 IS 9 BP 1024 EP 1039 DI 10.1175/1520-0469(2004)061<1024:SPOAOT>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 816HZ UT WOS:000221102300004 ER PT J AU Duda, DP Minnis, P Nguyen, L Palikonda, R AF Duda, DP Minnis, P Nguyen, L Palikonda, R TI A case study of the development of contrail clusters over the Great Lakes SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID CLOUD PROPERTIES; CIRRUS CLOUDS; MICROPHYSICAL PROPERTIES; RADIATIVE PROPERTIES; GLOBAL DISTRIBUTION; INFRARED RADIANCES; RELATIVE-HUMIDITY; SATELLITE DATA; AIRCRAFT WAKE; CLIMATE AB Widespread persistent contrails over the western Great Lakes during 9 October 2000 were examined using commercial flight data, coincident meteorological data, and satellite remote sensing data from several platforms. The data were analyzed to determine the atmospheric conditions under which the contrails formed and to measure several physical properties of the contrails, including areal coverage, spreading rates, fall speeds, and optical properties. Most of the contrails were located between 10.6 and 11.8 km in atmospheric conditions consistent with a modified form of the Appleman contrail formation theory. However, the Rapid Update Cycle-2 analyses have a dry bias in the upper-tropospheric relative humidity with respect to ice (RHI), as indicated by persistent contrail generation during the outbreak where RHI greater than or equal to 85%. The model analyses show that synoptic-scale vertical velocities affect the formation of persistent contrails. Areal coverage by linear contrails peaked at 30 000 km(2), but the maximum contrail-generated cirrus coverage was over twice as large. Contrail spreading rates averaged around 2.7 km h(-1), and the contrails were visible in the 4-km Geostationary Operational Environmental Satellite ( GOES) imagery approximately 1 h after formation. Contrail fall speed estimates were between 0.00 and 0.045 m s(-1) based on observed contrail advection rates. Optical depth measurements ranged from 0.1 to 0.6, with consistent differences between remote sensing methods. Contrail formation density was roughly correlated with air traffic density after the effects of competing cloud coverage, humidity, and vertical velocity were considered. Improved tropospheric humidity measurements are needed for realistic simulations of contrail and cirrus development. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Hampton Univ, Hampton, VA 23668 USA. AS&M Inc, Hampton, VA USA. RP Duda, DP (reprint author), NASA, Langley Res Ctr, MS 420, Hampton, VA 23681 USA. EM d.p.duda@larc.nasa.gov RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 41 TC 27 Z9 27 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY PY 2004 VL 61 IS 10 BP 1132 EP 1146 DI 10.1175/1520-0469(2004)061<1132:ACSOTD>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 820IG UT WOS:000221380800003 ER PT J AU Atlas, D Ulbrich, CW Williams, CR AF Atlas, D Ulbrich, CW Williams, CR TI Physical origin of a wet microburst: Observations and theory SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RAINDROP SIZE DISTRIBUTION; NUMERICAL SIMULATIONS; MODEL; PRECIPITATION; SENSITIVITY; EVAPORATION; CONVECTION; GRAUPEL; STORM; HAIL AB A unique set of Doppler and polarimetric radar observations were made of a microburst-producing storm in Amazonia during the Tropical Rainfall Measuring Mission (TRMM) Large-Scale Biosphere - Atmosphere (LBA) field experiment. The key features are high reflectivity (50 dBZ) and modest size hail (up to 0.8 mm) in high liquid water concentrations (>4 g m(-3)) at the 5-km 0degreesC level, melting near the 3-km level as evidenced by the Doppler spectrum width on the profiler radar ( PR), by differential polarization on the S-band dual-polarized radar (S-POL), and a sharp downward acceleration from 2.8 to 1.6 km to a peak downdraft of 11 m s(-1), followed by a weak microburst of 15 m s(-1) at the surface. The latter features closely match the initial conditions and results of the Srivastava numerical model of a microburst produced by melting hail. It is suggested that only modest size hail in large concentrations that melt aloft can produce wet microbursts. The narrower the distribution of hail particle sizes, the more confined will be the layer of melting and negative buoyancy, and the more intense the microburst. It is hypothesized that the timing of the conditions leading to the microburst is determined by the occurrence of an updraft of proper magnitude in the layer in which supercooled water accounts for the growth of hail or graupel. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. Univ Colorado, Boulder, CO 80309 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Atlas, D (reprint author), NASA, Goddard Space Flight Ctr, Code 910, Greenbelt, MD 20771 USA. EM datlas@radar.gsfc.nasa.gov RI Williams, Christopher/A-2723-2015 OI Williams, Christopher/0000-0001-9394-8850 NR 22 TC 9 Z9 9 U1 2 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY PY 2004 VL 61 IS 10 BP 1186 EP 1196 DI 10.1175/1520-0469(2004)061<1186:POOAWM>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 820IG UT WOS:000221380800007 ER PT J AU Cheng, Y Canuto, VM Howard, AM AF Cheng, Y Canuto, VM Howard, AM TI Comments on "An improved model for the turbulent PBL'' - Reply SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Editorial Material ID LARGE-EDDY SIMULATION; ATMOSPHERIC BOUNDARY-LAYERS; CLOSURE-MODEL; FLOWS C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Canuto, VM (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM vcanuto@giss.nasa.gov NR 30 TC 1 Z9 1 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY PY 2004 VL 61 IS 10 BP 1200 EP 1204 DI 10.1175/1520-0469(2004)061<1200:R>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 820IG UT WOS:000221380800009 ER PT J AU Mannino, A Harvey, HR AF Mannino, A Harvey, HR TI Black carbon in estuarine and coastal ocean dissolved organic matter SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID DELAWARE ESTUARY; FLOW ULTRAFILTRATION; OPTICAL-PROPERTIES; SEDIMENTS; QUANTIFICATION; RIVER; PARTICULATE; SOILS; BAY AB We measured black carbon (BC) in ultrafiltered, high-molecular weight dissolved organic matter (UDOM) in surface waters of Delaware Bay, Chesapeake Bay, and the adjacent Atlantic Ocean (U.S.A.) to investigate the importance of riverine and estuarine dissolved organic matter (DOM) as a source of BC to the ocean. BC was 5-72% of UDOM-C (27 +/- 17%), which corresponds to 8.9 +/- 6.5% of dissolved organic carbon (DOC), with higher values in the heavily urbanized midbay region of the Delaware Estuary and lower yields in the river and coastal ocean. The spatial and seasonal distributions of BC along the salinity gradient of Delaware Bay suggest that the elevated levels of BC in surface water UDOM originate from localized sources, possibly from atmospheric deposition or release from resuspended sediments. BC in UDOM made up 4-7% of the DOC in the coastal Atlantic Ocean, revealing that river-estuary systems are important exporters of colloidal BC to the ocean. The annual flux of BC from Delaware Bay UDOM to the Atlantic Ocean was estimated at 2.4 X 10(10) g BC yr(-1), supporting the hypothesis that the DOC pool is an important contributor of BC to the ocean. C1 Univ Maryland, Ctr Environm Sci, Chesapeake Biol Lab, Solomons, MD 20688 USA. RP Mannino, A (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Processes, Mail Stop 971-1, Greenbelt, MD 20771 USA. EM antonio.mannino@nasa.gov RI Mannino, Antonio/I-3633-2014 NR 25 TC 72 Z9 78 U1 3 U2 38 PU AMER SOC LIMNOLOGY OCEANOGRAPHY PI WACO PA 5400 BOSQUE BLVD, STE 680, WACO, TX 76710-4446 USA SN 0024-3590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD MAY PY 2004 VL 49 IS 3 BP 735 EP 740 PG 6 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 869JQ UT WOS:000224979600012 ER PT J AU Diaz, FJ Hagan, DR Horvath, SM AF Diaz, FJ Hagan, DR Horvath, SM TI Plasma volume changes during maximal exercise in different postures SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Meeting Abstract CT Annual Meeting of the American-College-of-Sports-Medicine CY JUN 02-05, 2004 CL Indianapolis, IN SP Amer Coll Sports Med C1 Univ Guanajuato, Leon, Mexico. NASA, JSC, Houston, TX USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. EM msanchez@webtelmex.net.mx NR 0 TC 0 Z9 0 U1 0 U2 1 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0195-9131 J9 MED SCI SPORT EXER JI Med. Sci. Sports Exerc. PD MAY PY 2004 VL 36 IS 5 SU S MA 0435 BP S60 EP S60 PG 1 WC Sport Sciences SC Sport Sciences GA 913XG UT WOS:000228188300282 ER PT J AU Lee, SM Shackelford, LC Smith, SM Guilliams, ME Loehr, JA Shepherd, B Laughlin, MS Chauvin, J Hagan, RD AF Lee, SM Shackelford, LC Smith, SM Guilliams, ME Loehr, JA Shepherd, B Laughlin, MS Chauvin, J Hagan, RD TI Lean tissue mass and muscle strength: Does resistive exercise prevent space flight deconditioning? SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Meeting Abstract CT Annual Meeting of the American-College-of-Sports-Medicine CY JUN 02-05, 2004 CL Indianapolis, IN SP Amer Coll Sports Med C1 Wyle Labs, Houston, TX USA. NASA Johnson Space Ctr, Houston, TX USA. EM sleel@ems.jsc.nasa.gov NR 0 TC 2 Z9 2 U1 0 U2 2 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0195-9131 J9 MED SCI SPORT EXER JI Med. Sci. Sports Exerc. PD MAY PY 2004 VL 36 IS 5 SU S MA 1833 BP S272 EP S272 PG 1 WC Sport Sciences SC Sport Sciences GA 913XG UT WOS:000228188303006 ER PT J AU Murphy, MM Evans, RK Nindl, BC Sheehan, KM Wade, CM Scoville, CR AF Murphy, MM Evans, RK Nindl, BC Sheehan, KM Wade, CM Scoville, CR TI Longitudinal relationship between physical activity and lumbar bone density in men and women aged 18-29 SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Meeting Abstract CT Annual Meeting of the American-College-of-Sports-Medicine CY JUN 02-05, 2004 CL Indianapolis, IN SP Amer Coll Sports Med C1 US Army Res Inst Environm Med, Natick, MA USA. NASA Ames Res Ctr, Moffett Field, CA USA. EM michelle.murphy@na.amedd.army.mil NR 0 TC 1 Z9 1 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0195-9131 J9 MED SCI SPORT EXER JI Med. Sci. Sports Exerc. PD MAY PY 2004 VL 36 IS 5 SU S MA 2017 BP S290 EP S290 DI 10.1097/00005768-200405001-01390 PG 1 WC Sport Sciences SC Sport Sciences GA 913XG UT WOS:000228188303092 ER PT J AU Catalina, AV Stefanescu, DM Sen, S Kaukler, WF AF Catalina, AV Stefanescu, DM Sen, S Kaukler, WF TI Interaction of porosity with a planar solid/liquid interface SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID PHASE-FIELD METHOD; LEVEL SET METHOD; DENDRITIC SOLIDIFICATION; INVERSE SEGREGATION; CRYSTAL-GROWTH; PORE FORMATION; BINARY ALLOY; MICROPOROSITY; COMPUTATION; PREDICTION AB In this article, an investigation of the interaction between gas porosity and a planar solid/liquid (SL) interface is reported. A two-dimensional numerical model able to accurately track sharp SL interfaces during solidification of pure metals and alloys is proposed. The finite-difference method and a rectangular undeformed grid are used for computation. The SL interface is described through the points of intersection with the grid lines. Its motion is determined by the thermal and solute gradients at each particular point. Changes of the interface temperature because of capillarity or solute redistribution as well as any perturbation of the thermal and solute field produced by the presence of non-metallic inclusions can be computed. To validate the model, the dynamics of the interaction between a gas pore and a solidification front in metal alloys was observed using a state of the art X-ray transmission microscope (XTM). The experiments included observation of the distortion of the SL interface near a pore, real-time measurements of the growth rate, and the change in shape of the porosity during interaction with the SL interface in pure Al and Al-0.25 wt pct Au alloy. In addition, porosity-induced solute segregation patterns surrounding a pore were also quantified. C1 NASA, George C Marshall Space Flight Ctr, BAE SYST Analyt Solut, Huntsville, AL 35811 USA. Univ Alabama, Tuscaloosa, AL 35487 USA. Univ Alabama, Huntsville, AL 35899 USA. RP Catalina, AV (reprint author), NASA, George C Marshall Space Flight Ctr, BAE SYST Analyt Solut, Huntsville, AL 35811 USA. EM adrian.catalina@msfc.nasa.gov RI Stefanescu, Doru/G-8101-2012; OI Stefanescu, Doru M./0000-0001-5544-8396; Kaukler, William/0000-0002-7758-269X NR 47 TC 10 Z9 10 U1 1 U2 11 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD MAY PY 2004 VL 35A IS 5 BP 1525 EP 1538 DI 10.1007/s11661-004-0260-z PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 815OI UT WOS:000221051200010 ER PT J AU Tewari, SN Raj, SV Locci, IE AF Tewari, SN Raj, SV Locci, IE TI A comparison between growth morphology of "eutectic" cells/dendrites and single-phase cells/dendrites SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID DIRECTIONAL SOLIDIFICATION; LAMELLAR EUTECTICS; STABILITY; ALLOY C1 Cleveland State Univ, Chem & Biomed Engn Dept, Cleveland, OH 44115 USA. Case Western Reserve Univ, NASA, Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP Tewari, SN (reprint author), Cleveland State Univ, Chem & Biomed Engn Dept, Cleveland, OH 44115 USA. EM s.tewari@csuohio.edu NR 18 TC 5 Z9 5 U1 0 U2 4 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD MAY PY 2004 VL 35A IS 5 BP 1632 EP 1635 DI 10.1007/s11661-004-0269-3 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 815OI UT WOS:000221051200019 ER PT J AU Burbine, TH O'Brien, KM AF Burbine, TH O'Brien, KM TI Determining the possible building blocks of the Earth and Mars SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID OXYGEN-ISOTOPE VARIATIONS; TERRESTRIAL PLANETS; CHEMICAL-COMPOSITION; MARTIAN METEORITE; UPPER-MANTLE; CARBONACEOUS CHONDRITES; EARLY DIFFERENTIATION; ACCRETION HISTORY; TRANSITION ZONE; HIGH-PRESSURE AB To determine the possible building blocks of the Earth and Mars, 225,792,840 possible combinations of the bulk oxygen isotopic and chemical compositions of 13 chondritic groups at 5% mass increments were examined. Only a very small percentage of the combinations match the oxygen isotopic composition, the assumed bulk FeO concentration, and the assumed Fe/Al weight ratio for the Earth. Since chondrites are enriched in silicon relative to estimates of the bulk Earth, none of the combinations fall near the terrestrial magmatic fractionation trend line in Mg/Si-Al/Si space. More combinations match the oxygen isotopic composition and the assumed bulk FeO concentration for Mars. These combinations fall near the trend for shergottite meteorites in Mg/Si-Al/Si space. One explanation for the difficulty in forming Earth out of known chondrites is that the Earth may be composed predominately of material that did not survive to the present day as meteorites. Another explanation could be that significant amounts of silicon are sequestered in the core and/or lower mantle of the Earth. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 661, Greenbelt, MD 20771 USA. EM tburbine@lepvax.gsfc.nasa.gov NR 90 TC 23 Z9 24 U1 0 U2 6 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1086-9379 EI 1945-5100 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD MAY PY 2004 VL 39 IS 5 BP 667 EP 681 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 823BH UT WOS:000221584200002 ER PT J AU Rietmeijer, FJM Nuth, JA Nelson, RN AF Rietmeijer, FJM Nuth, JA Nelson, RN TI Laboratory hydration of condensed magnesiosilica smokes with implications for hydrated silicates in IDPs and comets SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID INTERPLANETARY DUST PARTICLES; MAJOR ELEMENT COMPOSITION; CARBONACEOUS CHONDRITES; MAGNESIUM SILICATES; SOLID CONDENSATION; HALLEY DUST; COSMIC DUST; EVOLUTION; CIRCUMSTELLAR; GRAINS AB Samples of silica-rich and MgO-rich condensed, amorphous magnesiosilica smokes were hydrated to monitor systematic mineralogical and chemical changes as a function of time and temperature controlled by their unique metastable eutectic compositions, their porous texture, and the ultrafine, nanometer grain size of all entities. At water supersaturated conditions, proto-phyllosilicates formed by spinodal-type homogeneous nucleation. Their formation and subsequent growth was entirely determined by the availability of water via pore spaces inherited from the original smokes and the textural continuity of magnesiosilica material with a mostly smectite-dehydroxylate composition. The results may have implications for the hydration of proto-CI material, the presence of rare periclase and brucite in primitive solar system bodies, and the pervasiveness of hydrated amorphous magnesiosilica dust and saponite proto-phyllosilicates in icy-protoplanets, such as comet nuclei. C1 Univ New Mexico, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Rietmeijer, FJM (reprint author), Univ New Mexico, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. EM fransjmr@unm.edu RI Nuth, Joseph/E-7085-2012 NR 69 TC 27 Z9 27 U1 0 U2 1 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 MAY PY 2004 VL 39 IS 5 BP 723 EP 746 PG 24 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 823BH UT WOS:000221584200007 ER PT J AU Pounds, KA Reeves, JN King, AR Page, KL AF Pounds, KA Reeves, JN King, AR Page, KL TI Exploring the complex X-ray spectrum of NGC 4051 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : active; galaxies : individual : NGC 4051; galaxies : Seyfert; X-rays : galaxies ID SEYFERT-1 GALAXY NGC-4051; REFLECTION GRATING SPECTROMETER; VELOCITY IONIZED OUTFLOW; ACTIVE GALACTIC NUCLEI; XMM-NEWTON; LINE EMISSION; IRON LINE; NGC 4051; VARIABILITY; ABSORPTION AB Archival XMM-Newton data on the nearby Seyfert galaxy NGC 4051, taken in relatively high- and low-flux states, offer a unique opportunity to explore the complexity of its X-ray spectrum. We find the hard X-ray band to be significantly affected by reflection from cold matter, which can also explain a non-varying, narrow Fe K fluorescent line. We interpret major differences between the high- and low-flux hard X-ray spectra in terms of the varying ionization (opacity) of a substantial column of outflowing gas. An emission-line spectrum in the low-flux state indicates an extended region of photoionized gas. A high- velocity, highly ionized outflow seen in the high- flux state spectrum can replenish the gas in the extended emission region over similar to10(3) yr, while having sufficient kinetic energy to contribute significantly to the hard X-ray continuum. C1 Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Pounds, KA (reprint author), Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. EM kap@star.le.ac.uk NR 45 TC 77 Z9 77 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 1 PY 2004 VL 350 IS 1 BP 10 EP 20 DI 10.1111/j.1365-2966.2004.07639.x PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 814MR UT WOS:000220979300007 ER PT J AU Wang, JJ AF Wang, JJ TI Evolution and structure of the mesoscale convection and its environment: A case study during the early onset of the southeast Asian summer monsoon SO MONTHLY WEATHER REVIEW LA English DT Article ID COARE SQUALL LINE; CHINA SEA MONSOON; TOGA COARE; BAIU FRONT; VERTICAL VELOCITY; DOPPLER RADAR; FEBRUARY 1993; CLOUD LINES; LIFE-CYCLE; PART I AB The evolution and structure of mesoscale convection in the South China Sea (SCS) region are documented for the first time mainly using the dual-Doppler radar dataset collected during the South China Sea Monsoon Experiment (SCSMEX) in 1998. In particular, this study focuses on the convection associated with a subtropical frontal passage during the early onset of the southeast Asian monsoon (SEAM). For the case of 15 May 1998, interaction between the tropical monsoon flow and frontal circulation played an important role in the evolution and structure of mesoscale convection. In the prefrontal region, the southwesterly monsoon flow converged with the southwesterly frontal flow to generate northeast-to-southwest-oriented convection. In the postfrontal region, the southwesterly monsoon flow converged with the northerly frontal flow to produce a wide convective line with an east-to-west orientation. In addition, the convergence between the southerly monsoon flow and the northerly postfrontal flow generated deeper and stronger low-level convergence. The postfrontal convection was more intense and deeper than the prefrontal convection. The precipitation and kinematic structure of mesoscale convection were studied with special attention to significant departures from archetypal tropical oceanic convection. On 15 May, prefrontal convection showed a straight upward rainfall and updraft pattern with little tilt as a result of moderate vertical wind shear. The maximum low-level convergence and updraft were 20-30 km behind instead of within 1-2 km of the leading edge. Although the convection was intense with maximum reflectivity over 50 dBZ, both pre- and postfrontal convection had a very limited stratiform region as a result of a dry environmental upper layer. The observed mesoscale convection had a tendency to form stratiform rain ahead of the convective rain, and two different modes of leading stratiform structure were found separately in pre- and postfrontal convection. C1 NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Ctr Earth Sci & Technol, Baltimore, MD 21228 USA. RP Wang, JJ (reprint author), NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Greenbelt, MD 20771 USA. EM jjwang@agnes.gsfc.nasa.gov NR 69 TC 14 Z9 20 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 2004 VL 132 IS 5 BP 1104 EP 1120 DI 10.1175/1520-0493(2004)132<1104:EASOTM>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 817RS UT WOS:000221195200005 ER PT J AU Rickenbach, TM AF Rickenbach, TM TI Nocturnal cloud systems and the diurnal variation of clouds and rainfall in southwestern Amazonia SO MONTHLY WEATHER REVIEW LA English DT Article ID SQUALL LINES; CONVECTIVE SYSTEMS; UNITED-STATES; PART II; CYCLE; PRECIPITATION; SURFACE; REGION; RADAR; REFLECTIVITY AB This paper examines the origins of a secondary nocturnal maximum in cloudiness and precipitation in southwestern Amazonia, a diurnal feature observed previously by many investigators. Analysis is based on satellite, radar, sounding, and profiler observations of precipitating systems and cloudiness from the Tropical Rainfall Measuring Mission Large-Scale Biosphere-Atmosphere (TRMM-LBA) and the coincident Wet-Season Atmospheric Mesoscale Campaign (WETAMC) field programs during the early 1999 wet season. The general finding is that following the collapse of the nearly ubiquitous and locally generated afternoon ("noon balloon'') convection, organized deep convection contributes to a postmidnight maximum in raining area and high cloudiness, and to a lesser extent rainfall. Nocturnal convective systems have the effect of weakening and delaying the onset of the following afternoon's convection. Many of these nocturnal convective events are traced to large-scale squall lines, which propagate westward thousands of kilometers from their point of origin along the northeast coast of Brazil. In addition, a previously undescribed nocturnal stratiform drizzle phenomenon, generated above the melting layer independently from deep convection, contributes significantly to nocturnal cloud cover. Results from this study underscore the complex influence of propagating large-scale organized convection in locally modulating the diurnal variation in clouds and rain. The greatest significance of the nocturnal drizzle may be the potential effect on the diurnal radiation budget by the extensive midlevel nocturnal clouds rather than their marginal contribution to nocturnal rainfall. C1 NASA, Goddard Space Flight Ctr, Mesoscale Proc Branch, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. RP Rickenbach, TM (reprint author), NASA, Goddard Space Flight Ctr, Mesoscale Proc Branch, Code 912, Greenbelt, MD 20771 USA. EM rickenba@umbc.edu NR 36 TC 49 Z9 53 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 2004 VL 132 IS 5 BP 1201 EP 1219 DI 10.1175/1520-0493(2004)132<1201:NCSATD>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 817RS UT WOS:000221195200010 ER PT J AU Auger, L Tangborn, AV AF Auger, L Tangborn, AV TI A wavelet-based reduced rank Kalman filter for assimilation of stratospheric chemical tracer observations SO MONTHLY WEATHER REVIEW LA English DT Article ID SEQUENTIAL DATA ASSIMILATION; SUPPORTED WAVELETS; DYNAMICS; SCHEMES; MODEL AB A suboptimal Kalman filter system that evolves error covariances in terms of a truncated set of wavelet coefficients has been developed for the assimilation of chemical tracer observations of CH4. The truncation is carried out in such a way that the resolution of the error covariance is reduced only in the zonal direction, where gradients are smaller. Assimilation experiments, which lasted 24 days and used different degrees of truncation, were carried out. These experiments reduced the number of elements in the covariance matrix by 90%, 97%, and 99% and the computational cost of covariance propagation by 80%, 93%, and 96%, respectively. The difference in both error covariance and the tracer field between the truncated and full systems over this period was not found to be growing after about 5 days of assimilation. The largest errors in the tracer fields were found to occur in regions of largest zonal gradients at times when observations were made in the immediate vicinity. C1 NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. Meteo France, Toulouse, France. Univ Maryland Baltimore Cty, JCET, Baltimore, MD 21228 USA. RP Tangborn, AV (reprint author), NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Code 900-3, Greenbelt, MD 20771 USA. EM tangborn@gma.gsfc.nasa.gov NR 18 TC 5 Z9 5 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 2004 VL 132 IS 5 BP 1220 EP 1237 DI 10.1175/1520-0493(2004)132<1220:AWRRKF>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 817RS UT WOS:000221195200011 ER PT J AU Teo, KBK Hash, DB Lacerda, RG Rupesinghe, NL Bell, MS Dalal, SH Bose, D Govindan, TR Cruden, BA Chhowalla, M Amaratunga, GAJ Meyyappan, JM Milne, WI AF Teo, KBK Hash, DB Lacerda, RG Rupesinghe, NL Bell, MS Dalal, SH Bose, D Govindan, TR Cruden, BA Chhowalla, M Amaratunga, GAJ Meyyappan, JM Milne, WI TI The significance of plasma heating in carbon nanotube and nanofiber growth SO NANO LETTERS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; INDUCTIVELY-COUPLED PLASMA; LOW-TEMPERATURE; PATTERNED GROWTH; DC PLASMA; GAS; REACTOR; SIMULATION; TRANSPORT; ABATEMENT AB The effect of the plasma on heating the growth substrate in plasma enhanced chemical vapor deposition (PECVD) of carbon nanotubes is characterized for the first time. This effect, which is commonly ignored in the nanotube/nanofiber literature, is the sole heating mechanism in this work for catalyst pretreatment and growth of straight and vertically aligned multiwalled carbon nanofibers. Significant temperatures, as high as 700 degreesC, are induced from a C2H2:NH3 direct current (dc) plasma with no other heat source present. To model the behavior of the plasma-heated substrate platform, we have developed a 1-D dc discharge model that incorporates a cathode platform energy balance, including ion bombardment, thermal radiation, and solid and gas conduction. The predicted gas-phase species present are correlated with the morphology of nanofibers grown by exclusive plasma heating as well as by heating from plasma in combination with a conventional resistive heater. The understanding of plasma heating and its accurate modeling are essential for reactor design for wafer scale production of vertically aligned nanofibers. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England. Rutgers State Univ, Dept Ceram & Mat Engn, Piscataway, NJ 08854 USA. RP Meyyappan, JM (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. EM M.Meyyappan@nasa.gov RI Lacerda, Rodrigo/N-2176-2014 NR 36 TC 105 Z9 106 U1 2 U2 25 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1530-6984 J9 NANO LETT JI Nano Lett. PD MAY PY 2004 VL 4 IS 5 BP 921 EP 926 DI 10.1021/nl049629g 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 820SQ UT WOS:000221410000032 ER PT J AU Lee, SI Howell, SW Raman, A Reifenberger, R Nguyen, CV Meyyappan, M AF Lee, SI Howell, SW Raman, A Reifenberger, R Nguyen, CV Meyyappan, M TI Nonlinear tapping dynamics of multi-walled carbon nanotube tipped atomic force microcantilevers SO NANOTECHNOLOGY LA English DT Article ID SCANNING PROBE MICROSCOPY; SURFACE AB The nonlinear dynamics of an atomic force microcantilever (AFM) with an attached multi-walled carbon nanotube (MWCNT) tip is investigated experimentally and theoretically. We present the experimental nonlinear frequency response of a MWCNT tipped microcantilever in the tapping mode. Several unusual features in the response distinguish it from those traditionally observed for conventional tips. The MWCNT tipped AFM probe is apparently immune to conventional imaging instabilities related to the coexistence of attractive and repulsive tapping regimes. A theoretical interaction model for the system using an Euler elastica MWCNT model is developed and found to predict several unusual features of the measured nonlinear response. C1 Purdue Univ, Sch Mech Engn, W Lafayette, IN 47907 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. ELORET Corp, Moffett Field, CA 94035 USA. RP Raman, A (reprint author), Purdue Univ, Sch Mech Engn, W Lafayette, IN 47907 USA. EM raman@ecn.purdue.edu NR 19 TC 39 Z9 39 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0957-4484 J9 NANOTECHNOLOGY JI Nanotechnology PD MAY PY 2004 VL 15 IS 5 BP 416 EP 421 AR PII S0957-4484(04)70259-7 DI 10.1088/0957/15/5/002 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Science & Technology - Other Topics; Materials Science; Physics GA 824IK UT WOS:000221679800003 ER PT J AU Hadjiev, VG Arepalli, S Nikolaev, P Jandl, S Yowell, L AF Hadjiev, VG Arepalli, S Nikolaev, P Jandl, S Yowell, L TI Enhanced Raman microprobe imaging of single-wall carbon nanotubes SO NANOTECHNOLOGY LA English DT Article ID SPECTROSCOPY; SCATTERING AB We explore Raman microprobe capabilities of visualizing single-wall carbon nanotubes (SWCNTs). Although this technique is limited to the micron scale, we demonstrate that images of individual SWCNTs, bundles, or their agglomerates can be generated by mapping Raman active elementary excitations. We measured the Raman response from carbon vibrations in SWCNTs excited by confocal scanning of a focused laser beam. Carbon vibrations reveal key characteristics of SWCNTs such as the nanotube diameter distribution (radial breathing modes (RBM), 100-300 cm(-1)), the presence of defects and functional groups (D-mode, 1300-1350 cm(-1)), strain and oxidation states of SWCNTs, as well as the metallic or semiconducting character of the tubes encoded in the lineshape of the G-modes at 1520-1600 cm(-1). In addition, SWCNTs are highly anisotropic scatterers. The Raman response from a SWCNT is maximal for incident light polarization parallel to the tube axis and vanishing for perpendicular directions. We show that the SWCNT bundle shape or direction can be determined, with some limitations, from a set of Raman images taken for two orthogonal directions of the incident light polarization. C1 Univ Houston, Texas Ctr Supercond & Adv Mat, Houston, TX 77204 USA. NASA, Lyndon B Johnson Space Ctr, GB Tech, Houston, TX 77058 USA. Univ Sherbrooke, Dept Phys, Sherbrooke, PQ J1K 2R1, Canada. RP Hadjiev, VG (reprint author), Univ Houston, Texas Ctr Supercond & Adv Mat, Houston, TX 77204 USA. RI Arepalli, Sivaram/A-5372-2010; Nikolaev, Pavel/B-9960-2009; Hadjiev, Viktor/A-7069-2008 OI Hadjiev, Viktor/0000-0001-8579-9357 NR 22 TC 15 Z9 15 U1 1 U2 7 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0957-4484 J9 NANOTECHNOLOGY JI Nanotechnology PD MAY PY 2004 VL 15 IS 5 BP 562 EP 567 AR PII S0957-4484(04)67814-7 DI 10.1088/0957-4484/15/5/028 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Science & Technology - Other Topics; Materials Science; Physics GA 824IK UT WOS:000221679800029 ER PT J AU Clements, DL Farrah, D Fox, M Rowan-Robinson, M Afonso, J AF Clements, DL Farrah, D Fox, M Rowan-Robinson, M Afonso, J TI Sub-millimeter emission from type la supernova host galaxies at z=0.5 SO NEW ASTRONOMY REVIEWS LA English DT Article; Proceedings Paper CT Workshop on Supernovae and Dust CY MAY 16-17, 2003 CL Paris, FRANCE DE supernovae; galaxies; dust; evolution ID STAR-FORMATION HISTORY; HUBBLE DEEP FIELD; LUMINOSITY DENSITY; LOCAL UNIVERSE; IA SUPERNOVAE; HIGH-REDSHIFT; DUST; EVOLUTION; MODELS AB We present deep sub-millimetre (sub-mm) observations of sixteen galaxies at z = 0.5, selected through being hosts of a type Ia supernova. Two galaxies are detected directly, and the sample, excluding the brightest detected galaxy, is detected statistically with a mean 850 mum flux of 0.92 +/- 0.33 mJy. We infer that the mean value of A(V) in normal galaxies is 0-80% higher than locally, in agreement with galaxy chemical evolution models. The dust in the brightest sub-mm object in our sample is best interpreted as normal 'cirrus' dust similar to that seen locally. This result, when combined with local surveys of type la supernovae, suggests that dust in supernova host galaxies at z = 0.5 Could produce a dimming that is comparable to the dimming attributed to accelerated expansion. This emphasizes the need to carefully monitor dust extinction when using type Ia supernovae to measure the cosmological parameters. As supernova surveys push to higher redshifts and to greater precision in extracted cosmological parameters, understanding the role of dust in these objects will become even more important. (C) 2003 Elsevier B.V. All rights reserved. C1 Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, London SW7 2BW, England. CALTECH, Jet Prop Lab, SIRTF Sci Ctr, Pasadena, CA 91125 USA. Astron Observ, CAAUL, P-1349018 Lisbon, Portugal. RP Clements, DL (reprint author), Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, Prince Consort Rd, London SW7 2BW, England. EM d.elements@imperial.ac.uk RI Afonso, Jose/B-5185-2013 OI Afonso, Jose/0000-0002-9149-2973 NR 14 TC 4 Z9 4 U1 1 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 MAY PY 2004 VL 48 IS 7-8 BP 629 EP 631 DI 10.1016/j.newar.2003.12.040 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 820LU UT WOS:000221391400013 ER PT J AU Riley, SC Fuss, HJ LeClair, LL AF Riley, SC Fuss, HJ LeClair, LL TI Ecological effects of hatchery-reared juvenile Chinook and Coho salmon on wild juvenile Salmonids in two Washington streams SO NORTH AMERICAN JOURNAL OF FISHERIES MANAGEMENT LA English DT Article ID BROWN TROUT; ATLANTIC SALMON; ONCORHYNCHUS-KISUTCH; RAINBOW-TROUT; INTERSPECIFIC COMPETITION; FORAGING BEHAVIOR; MICROHABITAT USE; STEELHEAD TROUT; FISH STOCKING; POPULATIONS AB We observed wild salmonid fry at sites downstream (treatment) and upstream (control) from experimental releases of hatchery-reared Chinook salmon Oncorhynchus tshawytscha smolts and coho salmon O. kisutch fry in two streams to estimate the effects of hatchery releases on the density, group size, microhabitat use, and size of wild fish. Most hatchery-reared Chinook salmon smolts that were released left treatment sites within a few days; hatchery-reared coho salmon fry remained at treatment sites for at least several weeks. We found limited evidence to suggest that the release of hatchery-reared Chinook salmon smolts or coho salmon fry caused consistent, significant effects on the density, group size, microhabitat use, or size of wild coho salmon fry in the two streams. We observed significant decreases in the densities of wild coho salmon and trout fry (steelhead [anadromous rainbow trout] O. mykiss and cutthroat trout O. clarki combined) after hatchery-reared Chinook salmon were released, but they did not occur when large numbers of hatchery fish were present at treatment sites. We observed an increase in the group size of wild coho salmon in one stream when Chinook salmon were released, but not in the other stream. We observed few changes in microhabitat use by wild coho salmon fry associated with the release of hatchery-reared fish; most changes were observed in only a single stream or occurred after only some of the releases. The lengths and weights of wild coho salmon fry over the sampling season were not significantly different between treatment and control sites in one study stream. These results suggest that small-scale releases of hatchery-reared Chinook or coho salmon have few significant ecological effects on wild salmonid fry in small, coastal Washington streams, particularly when wild fry occur at low densities. C1 Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Manchester Res Stn, Manchester, WA 98353 USA. Washington Dept Fish & Wildlife, Olympia, WA 98501 USA. RP Riley, SC (reprint author), Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Manchester Res Stn, POB 130, Manchester, WA 98353 USA. EM stephen.riley@noaa.gov NR 42 TC 9 Z9 9 U1 1 U2 9 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0275-5947 J9 N AM J FISH MANAGE JI North Am. J. Fish Manage. PD MAY PY 2004 VL 24 IS 2 BP 506 EP 517 DI 10.1577/M03-068.1 PG 12 WC Fisheries SC Fisheries GA 829RO UT WOS:000222067500015 ER PT J AU Diethelm, K Ford, NJ Freed, AD AF Diethelm, K Ford, NJ Freed, AD TI Detailed error analysis for a fractional Adams method SO NUMERICAL ALGORITHMS LA English DT Article DE fractional differential equation; Caputo derivative; Adams-Bashforth-Moulton method ID CONTINUOUS-TIME FINANCE; INTEGRAL-EQUATIONS; CALCULUS APPROACH; 2ND KIND; DISSIPATION; DIFFUSION; OPERATORS; DYNAMICS; VOLTERRA; MODELS AB We investigate a method for the numerical solution of the nonlinear fractional differential equation D(*)(alpha)y(t) = f(t, y(t)), equipped with initial conditions y((k))(0) = y(0)((k)) k = 0, 1,...,[a]-1. Here alpha may be an arbitrary positive real number, and the differential operator is the Caputo derivative. The numerical method can be seen as a generalization of the classical one-step Adams-Bashforth-Moulton scheme for first-order equations. We give a detailed error analysis for this algorithm. This includes, in particular, error bounds under various types of assumptions on the equation. Asymptotic expansions for the error are also mentioned briefly. The latter may be used in connection with Richardson's extrapolation principle to obtain modified versions of the algorithm that exhibit faster convergence behaviour. C1 Tech Univ Carolo Wilhelmina Braunschweig, Inst Computat Math, D-38106 Braunschweig, Germany. Chester Coll Higher Educ, Dept Math, Chester CH1 4BJ, Cheshire, England. NASA, Polymers Branch, John H Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP Diethelm, K (reprint author), Tech Univ Carolo Wilhelmina Braunschweig, Inst Computat Math, Pockelsstr 14, D-38106 Braunschweig, Germany. EM K.Diethelm@tu-bs.de; njford@chester.ac.uk; Alan.D.Freed@nasa.gov OI Freed, Alan/0000-0002-3492-0628 NR 46 TC 267 Z9 280 U1 1 U2 10 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1017-1398 J9 NUMER ALGORITHMS JI Numer. Algorithms PD MAY PY 2004 VL 36 IS 1 BP 31 EP 52 DI 10.1023/B:NUMA.0000027736.85078.be PG 22 WC Mathematics, Applied SC Mathematics GA 820LG UT WOS:000221389800003 ER PT J AU Refaat, TF Abedin, MN Bhat, IB Dutta, PS Singh, UN AF Refaat, TF Abedin, MN Bhat, IB Dutta, PS Singh, UN TI Characterization of InGaSb/GaSb p-n photodetectors in the 1.0-to 2.4-mu m wavelength range SO OPTICAL ENGINEERING LA English DT Editorial Material DE infrared; detectors; epitaxy; spectral response; detectivity AB Optical and electrical characteristics of InGaSb p-n photodetectors are presented at different temperatures. The device structures were grown on GaSb substrates using organic metal vapor phase epitaxy. Spectral calibration indicates peak responsivity around 2 mum, equivalent to 58% quantum efficiency, with 2.3-mum cutoff at room temperature. Reducing the device temperature increases the responsivity and shifts the cutoff wavelength to a shorter value. Current voltage measurements at different temperatures indicate that tunneling is the primary leakage current mechanism. Assuming Johnson limited performance, detectivity calculations resulted in 4 x 10(10) cm Hz(1/2)/W indicating that InGaSb is a superior material for 2-mum detection applications. (C) 2004 Society of Photo-Optical Instrumentation Engineers. C1 Sci & Technol Corp, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Laser & Electroopt Branch, Hampton, VA 23681 USA. Rensselaer Polytech Inst, Dept Elect Comp & Syst Engn, Troy, NY 12180 USA. RP Refaat, TF (reprint author), Sci & Technol Corp, 5 Dryden St,MS 468, Hampton, VA 23681 USA. EM tamer@stcnet.com NR 7 TC 6 Z9 6 U1 0 U2 4 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAY PY 2004 VL 43 IS 5 BP 1014 EP 1015 DI 10.1117/1.1695566 PG 2 WC Optics SC Optics GA 821JS UT WOS:000221456900004 ER PT J AU Florescu, M John, S AF Florescu, M John, S TI Resonance fluorescence in photonic band gap waveguide architectures: Engineering the vacuum for all-optical switching SO PHYSICAL REVIEW A LA English DT Article ID SPONTANEOUS EMISSION; ABSORPTION; ATOMS; SYSTEMS; CAVITY; EDGE AB We describe the spectral characteristics of the radiation scattered by two-level atoms (quantum dots) driven by a strong external field, and coupled to a photonic crystal radiation reservoir. We show that in the presence of strong variations with the frequency of the photonic reservoir density of states, the atomic, Mollow, sideband components of the scattered intensity can be strongly modified. Consequently, a weak optical probe field experiences a substantial differential gain in response to slight variations in the intensity of an optical driving field. We suggest that these effects may be of relevance to all-optical transistor action in photonic crystals. Using a specific photonic crystal heterostructure, we suggest that an all-optical microtransistor based on photonic crystals may operate at less than 100 nW switching threshold power. Collective N-atom effects substantially enhance this optical switching effect. Near the switching threshold intensity, collective effects are manifest in the N-2 scaling of the intensity spectrum (reminiscent of superradiance). Above and below this critical region, the gain spectrum widens (linearly with N). This correspondingly reduces the switching time scales of the atomic system in response to external fields. Furthermore, the quantum degree of second-order coherence exhibits unusual features. Scattered photons display a variable degree of antibunching as function of driving laser field intensity and the photonic density of states discontinuity. We analyze the effects of the inhomogeneous atomic line broadening on the amplification process. We show, using suitable photonic density of states engineering, that it is possible to select a narrow spectral range around the central frequency of the atomic frequency distribution over which amplification and switching occur. This is done either by spectral decoupling of the active elements from the electromagnetic field (through the introduction of band gaps at specified spectral locations) or through incoherent pumping to selectively saturate atoms outside the spectral region chosen for amplification. C1 Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, Canada. RP Florescu, M (reprint author), CALTECH, Jet Prop Lab, Mail Stop 126-347,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM marian@physics.utoronto.ca RI Florescu, Marian/E-9009-2010 NR 34 TC 54 Z9 54 U1 1 U2 10 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY PY 2004 VL 69 IS 5 AR 053810 DI 10.1103/PhysRevA.69.053810 PG 21 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 826FC UT WOS:000221813700150 ER PT J AU Abbott, B Abbott, R Adhikari, R Ageev, A Allen, B Amin, R Anderson, SB Anderson, WG Araya, M Armandula, H Asiri, F Aufmuth, P Aulbert, C Babak, S Balasubramanian, R Ballmer, S Barish, BC Barker, D Barker-Patton, C Barnes, M Barr, B Barton, MA Bayer, K Beausoleil, R Belczynski, K Bennett, R Berukoff, SJ Betzwieser, J Bhawal, B Bilenko, IA Billingsley, G Black, E Blackburn, K Bland-Weaver, B Bochner, B Bogue, L Bork, R Bose, S Brady, PR Braginsky, VB Brau, JE Brown, DA Brozek, S Bullington, A Buonanno, A Burgess, R Busby, D Butler, WE Byer, RL Cadonati, L Cagnoli, G Camp, JB Cantley, CA Cardenas, L Carter, K Casey, MM Castiglione, J Chandler, A Chapsky, J Charlton, P Chatterji, S Chen, Y Chickarmane, V Chin, D Christensen, N Churches, D Colacino, C Coldwell, R Coles, M Cook, D Corbitt, T Coyne, D Creighton, JDE Creighton, TD Crooks, DRM Csatorday, P Cusack, BJ Cutler, C D'Ambrosio, E Danzmann, K Davies, R Daw, E DeBra, D Delker, T DeSalvo, R Dhurandhar, S Diaz, M Ding, H Drever, RWP Dupuis, RJ Ebeling, C Edlund, J Ehrens, P Elliffe, EJ Etzel, T Evans, M Evans, T Fallnich, C Farnham, D Fejer, MM Fine, M Finn, LS Flanagan, E Freise, A Frey, R Fritschel, P Frolov, V Fyffe, M Ganezer, KS Giaime, JA Gillespie, A Goda, K Gonzalez, G Gossler, S Grandclement, P Grant, A Gray, C Gretarsson, AM Grimmett, D Grote, H Grunewald, S Guenther, M Gustafson, E Gustafson, R Hamilton, WO Hammond, M Hanson, J Hardham, C Harry, G Hartunian, A Heefner, J Hefetz, Y Heinzel, G Heng, IS Hennessy, M Hepler, N Heptonstall, A Heurs, M Hewitson, M Hindman, N Hoang, P Hough, J Hrynevych, M Hua, W Ingley, R Ito, M Itoh, Y Ivanov, A Jennrich, O Johnson, WW Johnston, W Jones, L Jungwirth, D Kalogera, V Katsavounidis, E Kawabe, K Kawamura, S Kells, W Kern, J Khan, A Killbourn, S Killow, CJ Kim, C King, C King, P Klimenko, S Kloevekorn, P Koranda, S Kotter, K Kovalik, J Kozak, D Krishnan, B Landry, M Langdale, J Lantz, B Lawrence, R Lazzarini, A Lei, M Leonhardt, V Leonor, I Libbrecht, K Lindquist, P Liu, S Logan, J Lormand, M Lubinski, M Luck, H Lyons, TT Machenschalk, B MacInnis, M Mageswaran, M Mailand, K Majid, W Malec, M Mann, F Marin, A Marka, S Maros, E Mason, J Mason, K Matherny, O Matone, L Mavalvala, N McCarthy, R McClelland, DE McHugh, M McNamara, P Mendell, G Meshkov, S Messenger, C Mitrofanov, VP Mitselmakher, G Mittleman, R Miyakawa, O Miyoki, S Mohanty, S Moreno, G Mossavi, K Mours, B Mueller, G Mukherjee, S Myers, J Nagano, S Nash, T Naundorf, H Nayak, R Newton, G Nocera, F Nutzman, P Olson, T O'Reilly, B Ottaway, DJ Ottewill, A Ouimette, D Overmier, H Owen, BJ Papa, MA Parameswariah, C Parameswariah, V Pedraza, M Penn, S Pitkin, M Plissi, M Pratt, M Quetschke, V Raab, F Radkins, H Rahkola, R Rakhmanov, M Rao, SR Redding, D Regehr, MW Regimbau, T Reilly, KT Reithmaier, K Reitze, DH Richman, S Riesen, R Riles, K Rizzi, A Robertson, DI Robertson, NA Robison, L Roddy, S Rollins, J Romano, JD Romie, J Rong, H Rose, D Rotthoff, E Rowan, S Rudiger, A Russell, P Ryan, K Salzman, I Sanders, GH Sannibale, V Sathyaprakash, B Saulson, PR Savage, R Sazonov, A Schilling, R Schlaufman, K Schmidt, V Schofield, R Schrempel, M Schutz, BF Schwinberg, P Scott, SM Searle, AC Sears, B Seel, S Sengupta, AS Shapiro, CA Shawhan, P Shoemaker, DH Shu, QZ Sibley, A Siemens, X Sievers, L Sigg, D Sintes, AM Skeldon, K Smith, JR Smith, M Smith, MR Sneddon, P Spero, R Stapfer, G Strain, KA Strom, D Stuver, A Summerscales, T Sumner, MC Sutton, PJ Sylvestre, J Takamori, A Tanner, DB Tariq, H Taylor, I Taylor, R Thorne, KS Tibbits, M Tilav, S Tinto, M Tokmakov, KV Torres, C Torrie, C Traeger, S Traylor, G Tyler, W Ugolini, D Vallisneri, M van Putten, M Vass, S Vecchio, A Vorvick, C Vyachanin, SP Wallace, L Walther, H Ward, H Ware, B Watts, K Webber, D Weidner, A Weiland, U Weinstein, A Weiss, R Welling, H Wen, L Wen, S Whelan, JT Whitcomb, SE Whiting, BF Willems, PA Williams, PR Williams, R Willke, B Wilson, A Winjum, BJ Winkler, W Wise, S Wiseman, AG Woan, G Wooley, R Worden, J Yakushin, I Yamamoto, H Yoshida, S Zawischa, I Zhang, L Zotov, N Zucker, M Zweizig, J AF Abbott, B Abbott, R Adhikari, R Ageev, A Allen, B Amin, R Anderson, SB Anderson, WG Araya, M Armandula, H Asiri, F Aufmuth, P Aulbert, C Babak, S Balasubramanian, R Ballmer, S Barish, BC Barker, D Barker-Patton, C Barnes, M Barr, B Barton, MA Bayer, K Beausoleil, R Belczynski, K Bennett, R Berukoff, SJ Betzwieser, J Bhawal, B Bilenko, IA Billingsley, G Black, E Blackburn, K Bland-Weaver, B Bochner, B Bogue, L Bork, R Bose, S Brady, PR Braginsky, VB Brau, JE Brown, DA Brozek, S Bullington, A Buonanno, A Burgess, R Busby, D Butler, WE Byer, RL Cadonati, L Cagnoli, G Camp, JB Cantley, CA Cardenas, L Carter, K Casey, MM Castiglione, J Chandler, A Chapsky, J Charlton, P Chatterji, S Chen, Y Chickarmane, V Chin, D Christensen, N Churches, D Colacino, C Coldwell, R Coles, M Cook, D Corbitt, T Coyne, D Creighton, JDE Creighton, TD Crooks, DRM Csatorday, P Cusack, BJ Cutler, C D'Ambrosio, E Danzmann, K Davies, R Daw, E DeBra, D Delker, T DeSalvo, R Dhurandhar, S Diaz, M Ding, H Drever, RWP Dupuis, RJ Ebeling, C Edlund, J Ehrens, P Elliffe, EJ Etzel, T Evans, M Evans, T Fallnich, C Farnham, D Fejer, MM Fine, M Finn, LS Flanagan, E Freise, A Frey, R Fritschel, P Frolov, V Fyffe, M Ganezer, KS Giaime, JA Gillespie, A Goda, K Gonzalez, G Gossler, S Grandclement, P Grant, A Gray, C Gretarsson, AM Grimmett, D Grote, H Grunewald, S Guenther, M Gustafson, E Gustafson, R Hamilton, WO Hammond, M Hanson, J Hardham, C Harry, G Hartunian, A Heefner, J Hefetz, Y Heinzel, G Heng, IS Hennessy, M Hepler, N Heptonstall, A Heurs, M Hewitson, M Hindman, N Hoang, P Hough, J Hrynevych, M Hua, W Ingley, R Ito, M Itoh, Y Ivanov, A Jennrich, O Johnson, WW Johnston, W Jones, L Jungwirth, D Kalogera, V Katsavounidis, E Kawabe, K Kawamura, S Kells, W Kern, J Khan, A Killbourn, S Killow, CJ Kim, C King, C King, P Klimenko, S Kloevekorn, P Koranda, S Kotter, K Kovalik, J Kozak, D Krishnan, B Landry, M Langdale, J Lantz, B Lawrence, R Lazzarini, A Lei, M Leonhardt, V Leonor, I Libbrecht, K Lindquist, P Liu, S Logan, J Lormand, M Lubinski, M Luck, H Lyons, TT Machenschalk, B MacInnis, M Mageswaran, M Mailand, K Majid, W Malec, M Mann, F Marin, A Marka, S Maros, E Mason, J Mason, K Matherny, O Matone, L Mavalvala, N McCarthy, R McClelland, DE McHugh, M McNamara, P Mendell, G Meshkov, S Messenger, C Mitrofanov, VP Mitselmakher, G Mittleman, R Miyakawa, O Miyoki, S Mohanty, S Moreno, G Mossavi, K Mours, B Mueller, G Mukherjee, S Myers, J Nagano, S Nash, T Naundorf, H Nayak, R Newton, G Nocera, F Nutzman, P Olson, T O'Reilly, B Ottaway, DJ Ottewill, A Ouimette, D Overmier, H Owen, BJ Papa, MA Parameswariah, C Parameswariah, V Pedraza, M Penn, S Pitkin, M Plissi, M Pratt, M Quetschke, V Raab, F Radkins, H Rahkola, R Rakhmanov, M Rao, SR Redding, D Regehr, MW Regimbau, T Reilly, KT Reithmaier, K Reitze, DH Richman, S Riesen, R Riles, K Rizzi, A Robertson, DI Robertson, NA Robison, L Roddy, S Rollins, J Romano, JD Romie, J Rong, H Rose, D Rotthoff, E Rowan, S Rudiger, A Russell, P Ryan, K Salzman, I Sanders, GH Sannibale, V Sathyaprakash, B Saulson, PR Savage, R Sazonov, A Schilling, R Schlaufman, K Schmidt, V Schofield, R Schrempel, M Schutz, BF Schwinberg, P Scott, SM Searle, AC Sears, B Seel, S Sengupta, AS Shapiro, CA Shawhan, P Shoemaker, DH Shu, QZ Sibley, A Siemens, X Sievers, L Sigg, D Sintes, AM Skeldon, K Smith, JR Smith, M Smith, MR Sneddon, P Spero, R Stapfer, G Strain, KA Strom, D Stuver, A Summerscales, T Sumner, MC Sutton, PJ Sylvestre, J Takamori, A Tanner, DB Tariq, H Taylor, I Taylor, R Thorne, KS Tibbits, M Tilav, S Tinto, M Tokmakov, KV Torres, C Torrie, C Traeger, S Traylor, G Tyler, W Ugolini, D Vallisneri, M van Putten, M Vass, S Vecchio, A Vorvick, C Vyachanin, SP Wallace, L Walther, H Ward, H Ware, B Watts, K Webber, D Weidner, A Weiland, U Weinstein, A Weiss, R Welling, H Wen, L Wen, S Whelan, JT Whitcomb, SE Whiting, BF Willems, PA Williams, PR Williams, R Willke, B Wilson, A Winjum, BJ Winkler, W Wise, S Wiseman, AG Woan, G Wooley, R Worden, J Yakushin, I Yamamoto, H Yoshida, S Zawischa, I Zhang, L Zotov, N Zucker, M Zweizig, J CA LIGO Sci Collaboration TI First upper limits from LIGO on gravitational wave bursts SO PHYSICAL REVIEW D LA English DT Article ID ROTATIONAL CORE COLLAPSE; LASER; INTERFEROMETER; DETECTORS; GEO-600; NETWORK; SEARCH; NOISE AB We report on a search for gravitational wave bursts using data from the first science run of the Laser Interferometer Gravitational Wave Observatory (LIGO) detectors. Our search focuses on bursts with durations ranging from 4 to 100 ms, and with significant power in the LIGO sensitivity band of 150 to 3000 Hz. We bound the rate for such detected bursts at less than 1.6 events per day at a 90% confidence level. This result is interpreted in terms of the detection efficiency for ad hoc waveforms (Gaussians and sine Gaussians) as a function of their root-sum-square strain h(rss); typical sensitivities lie in the range h(rss)similar to10(-19)-10(-17) strain/rootHz, depending on the waveform. We discuss improvements in the search method that will be applied to future science data from LIGO and other gravitational wave detectors. C1 CALTECH, LIGO, Pasadena, CA 91125 USA. Max Planck Inst Gravitat Phys, Albert Einstein Inst, D-14476 Golm, Germany. Max Planck Inst Gravitat Phys, Albert Einstein Inst, D-30167 Hannover, Germany. Australian Natl Univ, Canberra, ACT 0200, Australia. Calif State Univ Dominguez Hills, Carson, CA 90747 USA. CALTECH, CaRT, Pasadena, CA 91125 USA. Cardiff Univ, Cardiff CF2 3YB, S Glam, Wales. Carleton Coll, Northfield, MN 55057 USA. Cornell Univ, Ithaca, NY 14853 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Hobart & William Smith Coll, Geneva, NY 14456 USA. Interuniv Ctr Astron & Astrophys, Pune 411007, Maharashtra, India. MIT, LIGO, Cambridge, MA 02139 USA. LIGO Hanford Observ, Richland, WA 99352 USA. LIGO Livingston Observ, Livingston, LA 70754 USA. Louisiana State Univ, Baton Rouge, LA 70803 USA. Louisiana Tech Univ, Ruston, LA 71272 USA. Loyola Univ, New Orleans, LA 70118 USA. Max Planck Inst Quantum Opt, D-85748 Garching, Germany. Moscow MV Lomonosov State Univ, Moscow 119992, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Astron Observ Japan, Tokyo 1818588, Japan. Northwestern Univ, Evanston, IL 60208 USA. Salish Kootenai Coll, Pablo, MT 59855 USA. SE Louisiana Univ, Hammond, LA 70402 USA. Stanford Univ, Stanford, CA 94305 USA. Syracuse Univ, Syracuse, NY 13244 USA. Penn State Univ, University Pk, PA 16802 USA. Univ Texas, Brownsville, TX 78520 USA. Texas Southmost Coll, Brownsville, TX 78520 USA. Trinity Univ, San Antonio, TX 78212 USA. Leibniz Univ Hannover, D-30167 Hannover, Germany. Univ Illes Balears, E-07071 Palma de Mallorca, Spain. Univ Birmingham, Birmingham B15 2TT, W Midlands, England. Univ Florida, Gainesville, FL 32611 USA. Univ Glasgow, Glasgow G12 8QQ, Lanark, Scotland. Univ Michigan, Ann Arbor, MI 48109 USA. Univ Oregon, Eugene, OR 97403 USA. Univ Rochester, Rochester, NY 14627 USA. Univ Wisconsin, Milwaukee, WI 53201 USA. Washington State Univ, Pullman, WA 99164 USA. HP Labs, Palo Alto, CA USA. CNRS, Inst Astrophys Paris, GReCO, F-75700 Paris, France. Univ Tokyo, Inst Cosm Ray Res, Tokyo, Japan. Univ Coll Dublin, Dublin 2, Ireland. NASA, Jet Prop Lab, Pasadena, CA USA. RP CALTECH, LIGO, Pasadena, CA 91125 USA. RI Barker, David/A-5671-2013; Liu, Sheng/K-2815-2013; Vecchio, Alberto/F-8310-2015; Finn, Lee Samuel/A-3452-2009; Ottaway, David/J-5908-2015; Ottewill, Adrian/A-1838-2016; Sigg, Daniel/I-4308-2015; Frey, Raymond/E-2830-2016; Beausoleil, Raymond/C-5076-2009; McClelland, David/E-6765-2010; Kawabe, Keita/G-9840-2011; Lueck, Harald/F-7100-2011; Strain, Kenneth/D-5236-2011; Bilenko, Igor/D-5172-2012; Freise, Andreas/F-8892-2011; Mitrofanov, Valery/D-8501-2012; van Putten, Maurice/F-5237-2011; Pitkin, Matthew/I-3802-2013; Allen, Bruce/K-2327-2012; Vyatchanin, Sergey/J-2238-2012; Chen, Yanbei/A-2604-2013; Sylvestre, Julien/A-8610-2009; Schutz, Bernard/B-1504-2010; Casey, Morag/C-9703-2010; Rowan, Sheila/E-3032-2010; Raab, Frederick/E-2222-2011 OI Freise, Andreas/0000-0001-6586-9901; Whiting, Bernard F/0000-0002-8501-8669; Papa, M.Alessandra/0000-0002-1007-5298; Taylor, Ian/0000-0001-5040-0772; Aulbert, Carsten/0000-0002-1481-8319; Tanner, David/0000-0003-1940-4710; Vecchio, Alberto/0000-0002-6254-1617; Finn, Lee Samuel/0000-0002-3937-0688; Ottewill, Adrian/0000-0003-3293-8450; Sigg, Daniel/0000-0003-4606-6526; Frey, Raymond/0000-0003-0341-2636; McClelland, David/0000-0001-6210-5842; Lueck, Harald/0000-0001-9350-4846; Strain, Kenneth/0000-0002-2066-5355; Pitkin, Matthew/0000-0003-4548-526X; Allen, Bruce/0000-0003-4285-6256; Sylvestre, Julien/0000-0001-8136-4348; NR 45 TC 159 Z9 159 U1 5 U2 25 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD MAY PY 2004 VL 69 IS 10 AR 102001 DI 10.1103/PhysRevD.69.102001 PG 21 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 830BI UT WOS:000222096200007 ER PT J AU Ahmed, M Dodelson, S Greene, PB Sorkin, R AF Ahmed, M Dodelson, S Greene, PB Sorkin, R TI Everpresent Lambda SO PHYSICAL REVIEW D LA English DT Article ID NONZERO COSMOLOGICAL CONSTANT; COLD DARK-MATTER; ACCELERATING UNIVERSE; QUANTUM-GRAVITY; TIME; ENERGY; NEUTRALIZATION; CONSEQUENCES; SUPERNOVAE; MODELS AB A variety of observations indicate that the Universe is dominated by "dark energy" with negative pressure, one possibility for which is a cosmological constant. If the dark energy is a cosmological constant, a fundamental question is, why has it become relevant at so late an epoch, making today the only time in the history of the Universe at which the cosmological constant is of the order of the ambient density. We explore an answer to this question drawing on ideas from unimodular gravity, which entails fluctuations in the cosmological constant, and causal set theory, which predicts a specific magnitude for the fluctuations. The resulting ansatz provides a cosmological "constant" which fluctuates about zero, remaining always comparable to the ambient energy density. C1 Syracuse Univ, Dept Phys, Syracuse, NY 13244 USA. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Aspen Ctr Phys, Aspen, CO USA. Canadian Inst Theoret Astrophys, Toronto, ON, Canada. RP Ahmed, M (reprint author), Syracuse Univ, Dept Phys, Syracuse, NY 13244 USA. NR 47 TC 61 Z9 61 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAY PY 2004 VL 69 IS 10 AR 103523 DI 10.1103/PhysRevD.69.103523 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 830BI UT WOS:000222096200038 ER PT J AU Pan, Y Buonanno, A Chen, YB Vallisneri, M AF Pan, Y Buonanno, A Chen, YB Vallisneri, M TI Physical template family for gravitational waves from precessing binaries of spinning compact objects: Application to single-spin binaries SO PHYSICAL REVIEW D LA English DT Article ID BLACK-HOLE COALESCENCES; POST-NEWTONIAN ORDER; COALESCING BINARIES; NEUTRON-STARS; LASER-INTERFEROMETER; INSPIRALING BINARIES; MULTIPOLE MOMENTS; SEARCH TEMPLATES; ENERGY-LOSS; RADIATION AB The detection of the gravitational waves (GWs) emitted by precessing binaries of spinning compact objects is complicated by the large number of parameters (such as the magnitudes and initial directions of the spins, and the position and orientation of the binary with respect to the detector) that are required to model accurately the precession-induced modulations of the GW signal. In this paper we describe a fast matched-filtering search scheme for precessing binaries, and we adopt the physical template family proposed by Buonanno, Chen, and Vallisneri [Phys. Rev. D 67, 104025 (2003)] for ground-based interferometers. This family provides essentially exact waveforms, written directly in terms of the physical parameters, for binaries with a single significant spin, and for which the observed GW signal is emitted during the phase of adiabatic inspiral (for LIGO-I and VIRGO, this corresponds to a total mass Mless than or similar to15M). We show how the detection statistic can be maximized automatically over all the parameters (including the position and orientation of the binary with respect to the detector), except four (the two masses, the magnitude of the single spin, and the opening angle between the spin and the orbital angular momentum), so the template bank used in the search is only four-dimensional; this technique is relevant also to the searches for GW from extreme-mass-ratio inspirals and supermassive black hole inspirals to be performed using the space-borne detector LISA. Using the LIGO-I design sensitivity, we compute the detection threshold (similar to10) required for a false-alarm probability of 10(-3)/yr and the number of templates (similar to76 000) required for a minimum match of 0.97 for the mass range (m(1),m(2))=[7,12]Mx[1,3]M. C1 CALTECH, Pasadena, CA 91125 USA. CNRS, Inst Astrophys Paris, GReCO, F-75014 Paris, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Pasadena, CA 91125 USA. RI Chen, Yanbei/A-2604-2013 NR 73 TC 74 Z9 74 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD MAY PY 2004 VL 69 IS 10 AR 104017 DI 10.1103/PhysRevD.69.104017 PG 25 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 830BI UT WOS:000222096200057 ER PT J AU Metzger, PT AF Metzger, PT TI Comment on "Mechanical analog of temperature for the description of force distribution in static granular packings" SO PHYSICAL REVIEW E LA English DT Letter ID CONTACT FORCES AB It has been proposed by Ngan [Phys. Rev. E 68, 011301 (2003)] that the granular contact force distribution may be analytically derived by minimizing the analog of a thermodynamic free energy, in this case consisting of the total potential energy stored in the compressed contacts minus a particular form of entropy weighted by a parameter. The parameter is identified as a mechanical temperature. I argue that the particular form of entropy cannot be correct and as a result the proposed method produces increasingly errant results for increasing grain rigidity. This trend is evidenced in Ngan's published results and in other numerical simulations and experiments. C1 NASA, KSC Appl Phys Lab, John F Kennedy Space Ctr, Kennedy Space Ctr, FL 32899 USA. RP Metzger, PT (reprint author), NASA, KSC Appl Phys Lab, John F Kennedy Space Ctr, YA-C3-E, Kennedy Space Ctr, FL 32899 USA. EM Philip.T.Metzger@nasa.gov RI Metzger, Philip/R-3136-2016 OI Metzger, Philip/0000-0002-6871-5358 NR 24 TC 6 Z9 6 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1539-3755 J9 PHYS REV E JI Phys. Rev. E PD MAY PY 2004 VL 69 IS 5 AR 053301 DI 10.1103/PhysRevE.69.053301 PN 1 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 826EW UT WOS:000221813100071 ER PT J AU Knaepen, B Moin, P AF Knaepen, B Moin, P TI Large-eddy simulation of conductive flows at low magnetic Reynolds number SO PHYSICS OF FLUIDS LA English DT Article ID SUBGRID-SCALE; MAGNETOHYDRODYNAMIC TURBULENCE; FIELD AB Using the method of large-eddy simulation, we study decaying homogeneous turbulence of a conductive flow under the influence of an applied external magnetic field at low magnetic Reynolds number. In order to assess the performance of large-eddy simulation, comparison with high resolution (512(3)) direct numerical simulation is performed. Results show that the modeling of subgrid scales using the dynamic Smagorinsky model is very effective in the present context. (C) 2004 American Institute of Physics. C1 Stanford Univ, NASA, Ames Res Ctr, Ctr Turbulence Res, Stanford, CA 94305 USA. RP Knaepen, B (reprint author), Stanford Univ, NASA, Ames Res Ctr, Ctr Turbulence Res, Stanford, CA 94305 USA. EM bknaepen@stanford.edu NR 16 TC 57 Z9 57 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 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD MAY PY 2004 VL 16 IS 5 BP 1255 EP 1261 DI 10.1063/1.1651484 PG 7 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 812IG UT WOS:000220832600011 ER PT J AU Okong'o, N Bellan, J AF Okong'o, N Bellan, J TI Turbulence and fluid-front area production in binary-species, supercritical, transitional mixing layers SO PHYSICS OF FLUIDS LA English DT Article ID DIRECT NUMERICAL SIMULATIONS; FLAME STRETCH; HOMOGENEOUS TURBULENCE; SCALAR GRADIENT; SHEAR-LAYER; NITROGEN; HEPTANE; VORTICITY; STRAIN; DROPS AB Databases of transitional states obtained from direct numerical simulations of temporal, supercritical mixing layers for two species systems, O-2 - H-2 and C7H16 - N-2, are analyzed to elucidate species-specific turbulence aspects and features of fluid disintegration. Although the evolution of all layers is characterized by the formation of high-density-gradient magnitude (HDGM) regions, due to the specified, smaller initial density stratification, the C7H16 - N-2 layers display higher growth and increased global molecular mixing as well as larger turbulence levels than comparable O-2 - H-2 layers. However, smaller density gradients and lower mass-fraction gradients at the transitional state for the O-2 - H-2 system indicate that on a local basis, the layer exhibits an enhanced mixing, this being attributed to the increased mixture solubility and to mixture near-ideality. These thermodynamic features are found responsible for a larger irreversible entropy production (dissipation) in the O-2 - H-2 compared to the C7H16 - N-2 layers. The largest O-2 - H-2 dissipation is primarily concentrated in HDGM regions that are distortions of the initial density stratification boundary, whereas the largest C7H16 - N-2 dissipation is located in HDGM regions resulting from the mixing of the two fluids. To understand fluid disintegration, the area production of a fluid front perpendicular to the mass fraction gradient is calculated in a coordinate system moving with the relative velocity between the front and the flow. On a cross-stream local basis, the C7H16 - N-2 layers produce more area, and area production increases with smaller perturbation wavelengths combined with larger initial Reynolds numbers. The most active area-producing layer also exhibits the largest probability of having perpendicular vorticity and mass-fraction-gradient vectors. Analysis of the terms in the area production equation shows a large pressure-gradient-term root mean square contribution for the C7H16 - N-2 layers, due to the coincidence of regions with large magnitudes of pressure gradient with HDGM regions. Such coincidence is attributed to real-gas behavior, which is species-system specific, as the alignment of the pressure gradient and density gradient is similar for both species systems. The alignment of the mass fraction gradient with the strain rate is also species-system dependent. Independent of species system and of the initial conditions, the vorticity is preferentially aligned with the intermediate strain-rate eigendirection, indicating that eddy-viscosity-type models are not adequate for turbulent supercritical mixing. (C) 2004 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Okong'o, N (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 44 TC 12 Z9 13 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 MAY PY 2004 VL 16 IS 5 BP 1467 EP 1492 DI 10.1063/1.1688326 PG 26 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 812IG UT WOS:000220832600028 ER PT J AU Dimonte, G Youngs, DL Dimits, A Weber, S Marinak, M Wunsch, S Garasi, C Robinson, A Andrews, MJ Ramaprabhu, P Calder, AC Fryxell, B Biello, J Dursi, L MacNeice, P Olson, K Ricker, P Rosner, R Timmes, F Tufo, H Young, YN Zingale, M AF Dimonte, G Youngs, DL Dimits, A Weber, S Marinak, M Wunsch, S Garasi, C Robinson, A Andrews, MJ Ramaprabhu, P Calder, AC Fryxell, B Biello, J Dursi, L MacNeice, P Olson, K Ricker, P Rosner, R Timmes, F Tufo, H Young, YN Zingale, M TI A comparative study of the turbulent Rayleigh-Taylor instability using high-resolution three-dimensional numerical simulations: The Alpha-Group collaboration SO PHYSICS OF FLUIDS LA English DT Article ID CONSERVATIVE DIFFERENCE SCHEME; PIECEWISE-PARABOLIC METHOD; VARIABLE ACCELERATION; PARALLEL COMPUTATION; COMPRESSIBLE FLUIDS; BUBBLE MERGER; 2-PHASE FLOW; SIMPLE-MODEL; CONVECTION; SIMILARITY AB The turbulent Rayleigh-Taylor instability is investigated in the limit of strong mode-coupling using a variety of high-resolution, multimode, three dimensional numerical simulations (NS). The perturbations are initialized with only short wavelength modes so that the self-similar evolution (i.e., bubble diameter D(b)proportional to amplitude h(b)) occurs solely by the nonlinear coupling (merger) of saturated modes. After an initial transient, it is found that h(b) similar to alpha(b)Agt(2), where A=Atwood number, g=acceleration, and t=time. The NS yield D(b)similar toh(b)/3 in agreement with experiment but the simulation value alpha(b)similar to0.025+/-0.003 is smaller than the experimental value alpha(b)similar to0.057+/-0.008. By analyzing the dominant bubbles, it is found that the small value of alpha(b) can be attributed to a density dilution due to fine-scale mixing in our NS without interface reconstruction (IR) or an equivalent entrainment in our NS with IR. This may be characteristic of the mode coupling limit studied here and the associated alpha(b) may represent a lower bound that is insensitive to the initial amplitude. Larger values of alpha(b) can be obtained in the presence of additional long wavelength perturbations and this may be more characteristic of experiments. Here, the simulation data are also analyzed in terms of bubble dynamics, energy balance and the density fluctuation spectra. (C) 2004 American Institute of Physics. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Atom Weap Estab, Reading RG7 4PR, Berks, England. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Sandia Natl Labs, Livermore, CA 94551 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Texas A&M Univ, College Stn, TX 77843 USA. Univ Chicago, Chicago, IL 60637 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Calder, Alan/E-5348-2011; Young, Yuan-Nan/L-6413-2015; OI Young, Yuan-Nan/0000-0001-9771-5480; Zingale, Michael/0000-0001-8401-030X; Dursi, Jonathan/0000-0002-4697-798X NR 81 TC 209 Z9 212 U1 3 U2 34 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 1070-6631 EI 1089-7666 J9 PHYS FLUIDS JI Phys. Fluids PD MAY PY 2004 VL 16 IS 5 BP 1668 EP 1693 DI 10.1063/1.1688328 PG 26 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 812IG UT WOS:000220832600043 ER PT J AU Markarian, N Yeksel, M Khusid, B Kumar, A Tin, P AF Markarian, N Yeksel, M Khusid, B Kumar, A Tin, P TI Effects of clinorotation and positive dielectrophoresis on suspensions of heavy particles SO PHYSICS OF FLUIDS LA English DT Article ID MICROFLUIDICS AB Experiments in both microgravity (aboard the NASA research aircraft KC-135) and ground-based environments were conducted in a clinostat (a channel slowly rotated around its horizontal axis to simulate "weightlessness'') in which a dilute suspension of heavy, positively polarized spheres was exposed to a high-gradient strong ac electric field. While dielectrophoresis is shown to provide a powerful method for the manipulation and concentration of particles in clinostats, we find that clinorotation does not simulate the zero gravity morphology of the aggregation pattern due to an unexpectedly pronounced effect of a relatively weak, rotating gravity. This effect imposes certain limitations on the use of ground-based tests for predicting the operation of electrotechnologies for the control and manipulation of suspensions in microgravity. (C) 2004 American Institute of Physics. C1 New Jersey Inst Technol, Newark, NJ 07102 USA. CUNY City Coll, Levich Inst, New York, NY 10031 USA. NASA, Glenn Res Ctr, Natl Ctr Micrograv Res Fluids & Combust, Cleveland, OH 44135 USA. RP Markarian, N (reprint author), New Jersey Inst Technol, Univ Hts, Newark, NJ 07102 USA. OI Khusid, Boris/0000-0002-8604-1051 NR 11 TC 3 Z9 3 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD MAY PY 2004 VL 16 IS 5 BP 1826 EP 1829 DI 10.1063/1.1699154 PG 4 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 812IG UT WOS:000220832600057 ER PT J AU Birn, J Thomsen, MF Hesse, M AF Birn, J Thomsen, MF Hesse, M TI Electron acceleration in the dynamic magnetotail: Test particle orbits in three-dimensional magnetohydrodynamic simulation fields SO PHYSICS OF PLASMAS LA English DT Article ID PLASMA SHEET ION; MHD FIELDS; GEOSYNCHRONOUS OBSERVATIONS; ENERGETIC ELECTRONS; EARTHS MAGNETOTAIL; SYNCHRONOUS ORBIT; SUBSTORM; ENERGIZATION; INJECTIONS; MAGNETOSPHERE AB Electron acceleration and energetic electron flux increases in the inner tail are investigated on the basis of test-particle orbits in the dynamic fields of a three-dimensional magnetohydrodynamic simulation of neutral line formation and dipolarization in the magnetotail. Past models have mostly considered equatorial orbits, using the gyrocenter drift approximation. In this paper, the investigation is extended to include nonequatorial drifts and full orbit integrations in regions where the drift approximation breaks down. Typical acceleration mechanisms consist of betatron acceleration at large pitch angles and Fermi acceleration at small pitch angles, resulting from the dipolarization and shortening of field lines moving earthward from the neutral line. In comparison, acceleration at the near-Earth neutral line plays a negligible role in flux increases observed in the near tail. Energetic electron fluxes appear preferentially enhanced around 90degrees pitch angle, so that restriction to those pitch angles might lead to an overestimate of flux increases. Otherwise, the results explain the observed limitation of the range of flux enhancements between a few keV and a few hundred keV. (C) 2004 American Institute of Physics. C1 Los Alamos Natl Lab, Los Alamos, NM 87544 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Birn, J (reprint author), Los Alamos Natl Lab, Los Alamos, NM 87544 USA. EM jbirn@lanl.gov RI Hesse, Michael/D-2031-2012 NR 32 TC 49 Z9 49 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 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 2004 VL 11 IS 5 BP 1825 EP 1833 DI 10.1063/1.1704641 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 816PU UT WOS:000221122600016 ER PT J AU Osherovich, V Fainberg, J AF Osherovich, V Fainberg, J TI Dependence of frequency of nonlinear cold plasma cylindrical oscillations on electron density SO PHYSICS OF PLASMAS LA English DT Article ID HARMONIC LANGMUIR-WAVES AB For cold plasma, the frequency of small amplitude Langmuir oscillations along one Cartesian coordinate is omega(po)=root4pie(2)n(o)/m(e), where n(p)=n(o) is the constant proton density which is equal to the average electron density (n(e)) over bar. This formula for omega(po) is the basis for measurements of (n(e)) over bar in passive and active radio experiments located on spacecraft. We find that for cold plasma nonlinear cylindrical oscillations (n(e)) over bar >n(p) (i.e., a buildup of negative space charge near the axis of the cylinder). The resulting frequency of oscillations omega(pe) is greater than omega(po). The relation between omega(pe) and (n(e)) over bar is found to be logarithmic: omega(pe)=omega(po)[1+ln((n(e)) over bar /n(o))/12] with 0.5% accuracy for the range 1less than or equal to(n(e)) over bar /n(p)<6. For quasi-neutral plasma, when (n(e)) over bar /n(p)approximate to1, the logarithmic formula reduces to the linear one: omega(pe)=omega(po)[11/12+((n(e)) over bar /n(p))/12]. For (n(e)) over bar /n(p)>>6, omega(pe) approaches an upper limit of root2omega(po). These results are expected to be helpful in diagnostics of (n(e)) over bar in the solar wind and in magnetospheric plasmas as well as in laboratory plasmas where cylindrical symmetry is present. (C) 2004 American Institute of Physics. C1 NASA, Goddard Space Flight Ctr, L3, Greenbelt, MD 20771 USA. RP Osherovich, V (reprint author), NASA, Goddard Space Flight Ctr, L3, Code 690 2, Greenbelt, MD 20771 USA. NR 15 TC 1 Z9 1 U1 0 U2 0 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 MAY PY 2004 VL 11 IS 5 BP 2314 EP 2317 DI 10.1063/1.1690299 PG 4 WC Physics, Fluids & Plasmas SC Physics GA 816PU UT WOS:000221122600068 ER PT J AU Sehra, AK Whitlow, W AF Sehra, AK Whitlow, W TI Propulsion and power for 21st century aviation SO PROGRESS IN AEROSPACE SCIENCES LA English DT Review AB Air transportation in the new millennium will require revolutionary solutions to meet public demand for improving safety, reliability, environmental compatibility, and affordability. NASA's vision for 21st century aircraft is to develop propulsion systems that are intelligent, highly efficient, virtually inaudible (outside airport boundaries), and have near zero harmful emissions (CO2 and NOx). This vision includes intelligent engines capable of adapting to changing internal and external conditions to optimally accomplish missions with either minimal or no human intervention. Distributed vectored propulsion will replace current two to four wing mounted and fuselage mounted engine configurations with a large number of small, mini, or micro engines. Other innovative concepts, such as the pulse detonation engine (PDE), which potentially can replace conventional gas turbine engines, also are reviewed. It is envisioned that a hydrogen economy will drive the propulsion system revolution towards the ultimate goal of silent aircrafts with zero harmful emissions. Finally, it is envisioned that electric drive propulsion based on fuel cell power will generate electric power, which in turn will drive propulsors to produce the desired thrust. This paper reviews future propulsion and power concepts that are under development at the National Aeronautics and Space Administration's (NASA) John H. Glenn Research Center at Lewis Field, Cleveland, Ohio, USA. Published by Elsevier Ltd. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NASA, Kennedy Space Ctr, Kennedy Space Ctr, FL 32899 USA. RP Sehra, AK (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd,MS 3-6, Cleveland, OH 44135 USA. EM arun.k.sehra@nasa.gov NR 43 TC 41 Z9 46 U1 4 U2 29 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 MAY-JUL PY 2004 VL 40 IS 4-5 BP 199 EP 235 DI 10.1016/j.paerosci.2004.06.003 PG 37 WC Engineering, Aerospace SC Engineering GA 854SW UT WOS:000223924600001 ER PT J AU Renbarger, T Chuss, DT Dotson, JL Griffin, GS Hanna, JL Loewenstein, RF Malhotra, PS Marshall, JL Novak, G Pernic, RJ AF Renbarger, T Chuss, DT Dotson, JL Griffin, GS Hanna, JL Loewenstein, RF Malhotra, PS Marshall, JL Novak, G Pernic, RJ TI Early results from SPARO: Instrument characterization and polarimetry of NGC 6334 SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID SUBMILLIMETER POLARIMETER; INFRARED OBSERVATIONS; ARRAY POLARIMETRY; GRAIN ALIGNMENT; STAR-FORMATION; POLARIZATION; DUST; EMISSION; COMPLEX; ORION AB The Submillimeter Polarimeter for Antarctic Remote Observations (SPARO) employs two nine-element arrays of He-3-cooled bolometers to measure linear polarization at mm. It is operated at the focal plane of the Viper telescope, located at the Amundsen-Scott South Pole Station. SPARO obtains better sensitivity to degree-scale polarized submillimeter emission than can be currently achieved with any other experiment. We describe the design of SPARO's optics, detectors, and electronics. We also review the design of the SPARO cryostat, which has already been discussed in a previous paper. We discuss the performance of SPARO and Viper during observations at the South Pole in 2000, and we present polarimetric observations of NGC 6334 made with SPARO. Finally, we compare these observations with submillimeter polarimetric observations of the same source made at the Caltech Submillimeter Observatory and the James Clerk Maxwell Telescope, and we discuss the implications of these three data sets for the magnetic field in NGC 6334. C1 Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. Univ Minnesota, Dept Phys & Astron, Minneapolis, MN 55455 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Chicago, Yerkes Observ, Williams Bay, WI 53191 USA. Case Western Reserve Univ, Sch Med, Cleveland, OH 44106 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. RP Renbarger, T (reprint author), Northwestern Univ, Dept Phys & Astron, 2145 Sheridan Rd, Evanston, IL 60208 USA. EM renbarge@physics.umn.edu RI Chuss, David/D-8281-2012 NR 37 TC 15 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 MAY PY 2004 VL 116 IS 819 BP 415 EP 424 DI 10.1086/383623 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 815UP UT WOS:000221067500004 ER PT J AU Lindeman, MA Bandler, S Brekosky, RP Chervenak, JA Figueroa-Feliciano, E Finkbeiner, FM Li, MJ Kilbourne, CA AF Lindeman, MA Bandler, S Brekosky, RP Chervenak, JA Figueroa-Feliciano, E Finkbeiner, FM Li, MJ Kilbourne, CA TI Impedance measurements and modeling of a transition-edge-sensor calorimeter SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID MO/AU TES MICROCALORIMETERS; X-RAY SPECTROSCOPY; SERIES ARRAY AB We describe a method for measuring the complex impedance of transition-edge-sensor (TES) calorimeters. Using this technique, we measured the impedance of a Mo/Au superconducting transition-edge-sensor calorimeter. The impedance data are in good agreement with our linear calorimeter model. From these measurements, we obtained measurements of unprecedented accuracy of the heat capacity and the gradient of resistance with respect to temperature and current of a TES calorimeter throughout the phase transition. The measurements probe the internal state of the superconductor in the phase transition and are useful for characterizing the calorimeter. (C) 2004 American Institute of Physics. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Swales Aerosp, Beltsville, MD 20705 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP Lindeman, MA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM Mark.A.Lindeman.1@gsfc.nasa.gov RI Bandler, Simon/A-6258-2010 OI Bandler, Simon/0000-0002-5112-8106 NR 14 TC 76 Z9 76 U1 0 U2 12 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 2004 VL 75 IS 5 BP 1283 EP 1289 DI 10.1063/1.1711144 PN 1 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 827BD UT WOS:000221872300019 ER PT J AU Kucuk, H Parker, G Baumgartner, ET AF Kucuk, H Parker, G Baumgartner, ET TI Robot positioning of flexible-link manipulator using vision SO ROBOTICA LA English DT Article DE machine vision; camera space manipulation; robot; vision system AB Vision-aided flexible link robot positoning using the Camera Space Manipulation (CSM) method is developed. The primary motivation for this work is to use an autonomous vision-aided robotic system to pick-up and accurately move a flexible object that it encounters. The work consists of analytical and experimental investigation of the performance of CSM for a kinematic model of the PUMA manipulator with a flexible structure at the wrist which accounts for the gravitation. Trade-offs between camera view parameters and axial deflection model parameters were investigated. View parameter reestimation and maneuvering resulted a very accurate placement of the end-effector at the target. C1 Nigde Univ, Aksaray Fac Engn, Aksaray, Turkey. Michigan Technol Univ, Houghton, MI 49931 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Kucuk, H (reprint author), Nigde Univ, Aksaray Fac Engn, Aksaray, Turkey. EM hkucuk@hotmail.com NR 11 TC 1 Z9 1 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH ST, NEW YORK, NY 10011-4211 USA SN 0263-5747 J9 ROBOTICA JI Robotica PD MAY-JUN PY 2004 VL 22 BP 301 EP 307 DI 10.1017/S0263574703005629 PN 3 PG 7 WC Robotics SC Robotics GA 832WV UT WOS:000222299300005 ER PT J AU Del Moro, D Berrilli, F Duvall, TL Kosovichev, AG AF Del Moro, D Berrilli, F Duvall, TL Kosovichev, AG TI Dynamics and structure of supergranulation SO SOLAR PHYSICS LA English DT Article ID TIME-DISTANCE HELIOSEISMOLOGY; SOLAR GRANULATION IMAGES; CHROMOSPHERIC NETWORK; INFORMATION ENTROPY; REGULAR STRUCTURES; MAGNETIC-FIELDS; VELOCITY FIELDS; PHOTOSPHERE; EVOLUTION; ATMOSPHERE AB In this paper we investigate the temporal evolution and geometric properties of solar supergranular features. For this purpose we apply an automatic feature-tracking algorithm to a 6-day time series of 18 near-surface flowmaps (Duvall and Gizon, 2000) containing 548 target objects. Lifetimes are calculated by measuring the time elapsing between the birth and death of each target. Using an exponential fit on the lifetime distribution of single supergranules we derived a mean lifetime of 22 hours. Based on the application of segmentation numerical procedures, we estimated characteristic geometric parameters such as area distributions of supergranular cells. We also derive the relationship between measured lifetime and the area of the supergranules. C1 Univ Roma Tor Vergata, Dipartimento Fis, I-00133 Rome, Italy. CNR, IFSI, I-00133 Rome, Italy. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. RP Del Moro, D (reprint author), Univ Roma Tor Vergata, Dipartimento Fis, I-00133 Rome, Italy. RI Duvall, Thomas/C-9998-2012; OI DEL MORO, DARIO/0000-0003-2500-5054 NR 29 TC 24 Z9 24 U1 1 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD MAY PY 2004 VL 221 IS 1 BP 23 EP 32 DI 10.1023/B:SOLA.0000033363.15641.8f PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 833OO UT WOS:000222347600003 ER PT J AU Berrilli, F Del Moro, D Consolini, G Pietropaolo, E Duvall, TL Koshovichev, AG AF Berrilli, F Del Moro, D Consolini, G Pietropaolo, E Duvall, TL Koshovichev, AG TI Structure properties of supergranulation and granulation SO SOLAR PHYSICS LA English DT Article ID TIME-DISTANCE HELIOSEISMOLOGY; SOLAR PHOTOSPHERE; REGULAR STRUCTURES AB We investigate spatial dislocation ordering of the solar structures associated with supergranulation and granulation scales. The supergranular and granular structures are automatically segmented from time-distance divergence maps and from broad-band images, respectively. The spatial dislocation ordering analysis is accomplished by applying the statistical method of Pair Correlation Function, (g)2(r), to segmented features in the solar fields. We compare the computed g(2)(r) functions obtained from both single and persistent, i.e., time-averaged, fields associated with supergranulation and granulation. We conclude that supergranulation and granulation patterns present a different topological order both in single and persistent fields. The analysis carried out on single fields suggests that the granulation behaves as an essentially random distribution of soft plasma features with a very broad distribution in size, while supergranulation behaves as a random distribution of close packed, coherent stiff features with a rather defined mean size. C1 Univ Roma Tor Vergata, Dipartimento Fis, I-00133 Rome, Italy. CNR, IFSI, I-00133 Rome, Italy. Univ Aquila, Dipartimento Fis, I-67100 Laquila, Italy. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. RP Berrilli, F (reprint author), Univ Roma Tor Vergata, Dipartimento Fis, I-00133 Rome, Italy. RI Duvall, Thomas/C-9998-2012; OI PIETROPAOLO, Ermanno/0000-0002-6633-9846; CONSOLINI, Giuseppe/0000-0002-3403-647X; DEL MORO, DARIO/0000-0003-2500-5054 NR 15 TC 18 Z9 18 U1 1 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD MAY PY 2004 VL 221 IS 1 BP 33 EP 45 DI 10.1023/B:SOLA.0000033368.00217.de PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 833OO UT WOS:000222347600004 ER PT J AU Johnson, NL AF Johnson, NL TI Space traffic management: concepts and practices SO SPACE POLICY LA English DT Article AB The value of a space traffic management system must weigh the historical and legally entrenched concept of the freedom of operation in near-Earth orbit against the potential benefits of a new regulatory regime. Most spacefaring nations do not yet exert control over the selection of orbital parameters for new space systems within their own countries, much less in an international context. The need for and potential effectiveness of such intrusive space traffic management in the foreseeable future have not yet been clearly established. Published by Elsevier Ltd. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Johnson, NL (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. EM nicholas.l.johnson@nasa.gov NR 15 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0265-9646 J9 SPACE POLICY JI Space Policy PD MAY PY 2004 VL 20 IS 2 BP 79 EP 85 DI 10.1016/j.spacepol.2004.02.002 PG 7 WC International Relations; Social Sciences, Interdisciplinary SC International Relations; Social Sciences - Other Topics GA 827IM UT WOS:000221892900002 ER PT J AU Lester, DF Yorke, HW Mather, JC AF Lester, DF Yorke, HW Mather, JC TI Does the lunar surface still offer value as a site for astronomical observatories? SO SPACE POLICY LA English DT Article DE Moon; observatories; astronomy AB Current thinking about the Moon as a destination has revitalized interest in lunar astronomical observatories. Once seen by a large scientific community as a highly enabling site, the dramatic improvement in capabilities for free-space observatories prompts reevaluation of this interest. Whereas the lunar surface offers huge performance advantages for astronomy over terrestrial sites, freespace locales such as Earth orbit or Lagrange points offer performance that is superior to what could be achieved on the Moon. While astronomy from the Moon may be cost-effective once infrastructure is there, it is in many respects no longer clearly enabling compared with free space. (C) 2004 Elsevier Ltd. All rights reserved. C1 Univ Texas, Dept Astron, Austin, TX 78712 USA. Univ Texas, McDonald Observ, Austin, TX 78712 USA. CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Lester, DF (reprint author), Univ Texas, Dept Astron, Austin, TX 78712 USA. EM dfl@astro.as.utexas.edu NR 21 TC 11 Z9 11 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0265-9646 J9 SPACE POLICY JI Space Policy PD MAY PY 2004 VL 20 IS 2 BP 99 EP 107 DI 10.1016/j.spacepol.2004.02.011 PG 9 WC International Relations; Social Sciences, Interdisciplinary SC International Relations; Social Sciences - Other Topics GA 827IM UT WOS:000221892900005 ER PT J AU Yoon, KE Noebe, RD Hellman, OC Seidman, DN AF Yoon, KE Noebe, RD Hellman, OC Seidman, DN TI Dependence of interfacial excess on the threshold value of the isoconcentration surface SO SURFACE AND INTERFACE ANALYSIS LA English DT Article; Proceedings Paper CT 48th International Field Emission Symposium CY JUL 07-11, 2002 CL LYON, FRANCE DE Ni-based superalloy; three-dimensional atom probe microscopy; heterophase interface; interfacial segregation ID 3-DIMENSIONAL ATOM-PROBE; MICROSCOPY; SUPERALLOY AB The proximity histogram (or proxigram for short) is used for analyzing data collected by a three-dimensional atom probe microscope. The interfacial excess of Re (2.41 +/- 0.68 atoms nm(-2)) is calculated by employing a proxigram in a completely geometrically independent way for gamma/gamma' interfaces in Rene N6, a third-generation single-crystal Ni-based superalloy. A possible dependence of interfacial excess on the variation of the threshold value of an isoconcentration surface is investigated using the data collected for Rene N6 alloy. It is demonstrated that the dependence of the interfacial excess value on the threshold value of the isoconcentration surface is weak. Copyright (C) 2004 John Wiley Sons, Ltd. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Washington, Dept Mat Sci & Engn, Seattle, WA 98195 USA. RP Seidman, DN (reprint author), Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. EM d-seidman@northwestern.edu RI Seidman, David/B-6697-2009; Felfer, Peter/H-6024-2011 NR 12 TC 30 Z9 30 U1 1 U2 7 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD MAY-JUN PY 2004 VL 36 IS 5-6 BP 594 EP 597 DI 10.1002/sia.1708 PG 4 WC Chemistry, Physical SC Chemistry GA 833YO UT WOS:000222377800048 ER PT J AU Natanson, GA AF Natanson, GA TI Explicit definition of the reaction coordinate for the Jackels-Gu-Truhlar projection technique to compute harmonic vibrational frequencies along the intrinsic reaction path SO THEORETICAL CHEMISTRY ACCOUNTS LA English DT Article DE intrinsic reaction path; reaction coordinate; harmonic frequencies; Jackels-Gu-Truhlar projection technique ID TRANSITION-STATE THEORY; NONLINEAR COMBINATION; QUARTIC ANHARMONICITY; PARTITION-FUNCTIONS; ENERGY-LEVELS; DYNAMICS; APPROXIMATION; FORMALISM; VARIABLES; MOLECULES AB It is shown that the Jackels-Gu-Truhlar projection technique for computing harmonic frequencies along the intrinsic reaction path is equivalent to use of a new, enormously broad family of the so-called hyperplanar-vibrational-surface (HVS) reaction coordinates, namely, for any arbitrarily chosen set of internal variables sigma, the appropriate HVS reaction coordinate, s(sigma), is implicitly defined via the requirement that it remains constant on any so-called orthogonal-to-path hyperplane in the coordinate space spanned by variables sigma. It is proven that s(sigma) defined in such a way satisfies the local Hofacker-Marcus conditions and therefore there is no linear term in a Taylor expansion of the potential in terms of vibrational coordinates Q(sigma). Since the transformation from Q(sigma) and s(sigma) to sigma is explicitly defined, one can use a standard technique to account for potential anharmonicities along the reaction path. C1 NASA, Goddard Space Flight Ctr, AI Solut Inc, Flight Dynam Facil, Greenbelt, MD 20771 USA. RP Natanson, GA (reprint author), NASA, Goddard Space Flight Ctr, AI Solut Inc, Flight Dynam Facil, Greenbelt, MD 20771 USA. EM natanson@ai-solutions.com NR 35 TC 2 Z9 2 U1 0 U2 1 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1432-881X J9 THEOR CHEM ACC JI Theor. Chem. Acc. PD MAY PY 2004 VL 112 IS 2 BP 68 EP 74 DI 10.1007/s00214-003-0560-1 PG 7 WC Chemistry, Physical SC Chemistry GA 817CM UT WOS:000221155600002 ER PT J AU Nemeth, MP AF Nemeth, MP TI Buckling of long compression-loaded anisotropic plates restrained against inplane lateral and shear deformations SO THIN-WALLED STRUCTURES LA English DT Article DE buckling; anisotropy; anisotropic plates; combined loads; laminated-composite plates; Poisson effects ID COMPOSITE PLATES; LAMINATED PLATES; BEHAVIOR AB An approach for synthesizing buckling results and behavior for thin balanced and unbalanced symmetric laminates that are subjected to uniform axial compression loads and elastically restrained against inplane expansion, contraction, and shear deformation is presented. This approach uses a nondimensional analysis for infinitely long, flexurally anisotropic plates (coupling between bending, and,twisting) that are subjected to combined mechanical loads and is based on nondimensional parameters. In addition, nondimensional loading parameters are derived that account for the effects of the elastic inplane deformation restraints, membrane orthotropy, and membrane anisotropy on the induced prebuckling stress state. The loading parameters are used to determine, buckling coefficients that include the effects of flexural orthotropy and flexural anisotropy. Many results are presented, for some selected laminates, that are intended to facilitate a structural designer's transition to the use of the generic buckling-design curves that are presented and discussed in the pap er. Several buckling response curves are presented that-provide physical insight into the behavior for combined loads, in addition to providing useful design data. An example is presented that demonstrates the use of the generic design curves, which are applicable to a wide, range of laminate constructions. The analysis Approach and generic results indicate the effects and characteristics of laminate orthotropy and anisotropy in a very general and unifying manner. Published by Elsevier Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Nemeth, MP (reprint author), NASA, Langley Res Ctr, M-S 188E, Hampton, VA 23681 USA. EM m.p.nemeth@larc.nasa.gov NR 21 TC 13 Z9 15 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0263-8231 J9 THIN WALL STRUCT JI Thin-Walled Struct. PD MAY PY 2004 VL 42 IS 5 BP 639 EP 685 DI 10.1016/j.tws.2003.12.004 PG 47 WC Engineering, Civil SC Engineering GA 818DA UT WOS:000221224600001 ER PT J AU Heintz, RA Nelson, BD Hudson, J Larsen, M Holland, L Wipfli, M AF Heintz, RA Nelson, BD Hudson, J Larsen, M Holland, L Wipfli, M TI Marine subsidies in freshwater: Effects of salmon carcasses on lipid class and fatty acid composition of juvenile coho salmon SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID PARR-SMOLT TRANSFORMATION; SALVELINUS-ALPINUS L; SOUTHEASTERN ALASKA; PACIFIC SALMON; ONCORHYNCHUS-KISUTCH; STREAM PRODUCTIVITY; ATLANTIC SALMON; STEELHEAD TROUT; FROZEN STORAGE; SASHIN-CREEK AB Returning adult salmon represent an important source of energy, nutrients, and biochemicals to their natal streams and may therefore have a quantitative effect on the energy levels of stream-resident salmonids. We tested this hypothesis by constructing simulated streams for coho salmon Oncorhynchus kisutch to which we added 0, 1, and 4 carcasses/m(2) (0, 0.71, and 2.85 kg wet mass/m(2)) of pink salmon O. gorbuscha. After 60 d we evaluated the lipid class and fatty acid composition of rearing coho salmon from the simulated streams; the lipid content and triacylglycerols of the coho salmon increased with increasing carcass density whereas phospholipids decreased. Increased amounts of triacylglycerols accounted for most of the lipid increase. In addition to increasing in concentration, the fatty acid composition of the triacylglycerols also changed with carcass density. Triacylglycerols of juvenile coho salmon from the control streams had significantly higher omega-3 : omega-6 ratios as a result of fivefold and sixfold increases in the concentrations of eicosapentanoic and docosahexanoic fatty acids, respectively. These data demonstrate an immediate nutritional benefit resulting from the introduction of salmon carcasses in juvenile coho salmon rearing habitat and indicate the utility of fatty acid and lipid class analysis for examining the effects of marine-derived nutrients on juvenile salmonids. C1 Natl Marine Fisheries Serv, Auke Bay Lab, Juneau, AK 99801 USA. US Forest Serv, Pacific NW Res Stn, Juneau, AK 99801 USA. RP Heintz, RA (reprint author), Natl Marine Fisheries Serv, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. EM ron.heintz@noaa.gov NR 43 TC 41 Z9 41 U1 3 U2 21 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD MAY PY 2004 VL 133 IS 3 BP 559 EP 567 DI 10.1577/T03-035.1 PG 9 WC Fisheries SC Fisheries GA 828ZM UT WOS:000222012400006 ER PT J AU Obayashi, S Sasaki, D Oyama, A AF Obayashi, S Sasaki, D Oyama, A TI Finding tradeoffs by using multiobjective optimization algorithms SO TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES LA English DT Article DE aerodynamics; CFD; design; compressor; multiobjective optimization; evolutionary computation; gradient-based method ID EVOLUTIONARY ALGORITHM; DESIGN AB The objective of the present study is to demonstrate performances of Evolutionary Algorithms (EAs) and conventional gradient-based methods for finding Pareto fronts. The multiobjective optimization algorithms are applied to analytical test problems as well as to the real-world problems of a compressor design. The comparison results clearly indicate the superiority of EAs in finding tradeoffs. C1 Tohoku Univ, Inst Fluid Sci, Sendai, Miyagi, Japan. Tohoku Univ, Dept Syst Informat Sci, Sendai, Miyagi, Japan. NASA, Glenn Res Ctr, Cleveland, OH USA. RP Obayashi, S (reprint author), Tohoku Univ, Inst Fluid Sci, Sendai, Miyagi, Japan. NR 20 TC 14 Z9 15 U1 0 U2 2 PU JAPAN SOC AERONAUT SPACE SCI PI TOKYO PA KOKUKAIKAN-BUNKAN 1-18-2 SHINBASHI MINATO-KU, TOKYO, JAPAN SN 0549-3811 J9 T JPN SOC AERONAUT S JI Trans. Jpn. Soc. Aeronaut. Space Sci. PD MAY PY 2004 VL 47 IS 155 BP 51 EP 58 DI 10.2322/tjsass.47.51 PG 8 WC Engineering, Aerospace SC Engineering GA 925YJ UT WOS:000229089300008 ER PT J AU Hedges, SB Kumar, S AF Hedges, SB Kumar, S TI Precision of molecular time estimates SO TRENDS IN GENETICS LA English DT Editorial Material ID CRETACEOUS-TERTIARY BOUNDARY; DIVERGENCE TIMES; CAMBRIAN EXPLOSION; METAZOAN PHYLA; EVOLUTION; CLOCKS; ORIGIN; ORGANISMS; MAMMALS; DIVERSIFICATION AB Molecular clocks are used to estimate the time of divergence of genes and species and have helped illuminate the evolutionary history of life. In a recent article, Graur and Martin raised concerns regarding confidence intervals of molecular time estimates and fossil calibrations. Although our past work was singled out, their concerns apply generally to the field, including their own previous studies. We believe that those concerns are unfounded. Graur and Martin use ad hoc methods for estimating confidence intervals and for the interpretation of fossil evidence, which led them to calculate overly wide confidence intervals and to make erroneous conclusions. In a separate article, Reisz and Muller propose that the bird-mammal fossil calibration used by us, and others, should be abandoned in favor of a bird-lizard calibration. However, other paleontologists disagree, and Reisz and Muller have failed to provide robust fossil evidence or to consider sequence availability. Molecular clocks have great potential but must be calibrated carefully. C1 Penn State Univ, NASA, Astrobiol Inst, University Pk, PA 16802 USA. Arizona State Univ, Ctr Evolutionary Funct Genomics, Arizona Biodesign Inst, Tempe, AZ 85287 USA. Arizona State Univ, Sch Life Sci, Tempe, AZ 85287 USA. Penn State Univ, Dept Biol, University Pk, PA 16802 USA. RP Hedges, SB (reprint author), Penn State Univ, NASA, Astrobiol Inst, University Pk, PA 16802 USA. EM sbh1@psu.edu RI Kumar, Sudhir/F-1411-2011 NR 52 TC 155 Z9 161 U1 1 U2 20 PU ELSEVIER SCIENCE LONDON PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0168-9525 J9 TRENDS GENET JI Trends Genet. PD MAY PY 2004 VL 20 IS 5 BP 242 EP 247 DI 10.1016/j.tig.2004.03.004 PG 6 WC Genetics & Heredity SC Genetics & Heredity GA 821BV UT WOS:000221435500007 PM 15109778 ER PT J AU DellaCorte, C AF DellaCorte, C TI Don't miss out on WTC III SO TRIBOLOGY & LUBRICATION TECHNOLOGY LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP DellaCorte, C (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM cdellacorte@stle.org NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 0024-7154 J9 TRIBOL LUBR TECHNOL JI Tribol. Lubr. Technol. PD MAY PY 2004 VL 60 IS 5 BP 6 EP 6 PG 1 WC Engineering, Mechanical SC Engineering GA 815DN UT WOS:000221023100002 ER PT J AU Brown, J Latombe, JC Montgomery, K AF Brown, J Latombe, JC Montgomery, K TI Real-time knot-tying simulation SO VISUAL COMPUTER LA English DT Article DE rope simulation; knot tying; self-collision detection; collision management; surgical suturing ID FRICTION AB The real-time simulation of rope, and knot tying in particular, raises difficult issues in contact detection and management. Some practical knots can only be achieved by complicated crossings of the rope, yielding multiple simultaneous contacts, especially when the rope is pulled tight. This paper describes a graphical simulator that allows a user to grasp and smoothly manipulate a virtual rope and to tie arbitrary knots, including knots around other objects, in real time. A first component of the simulator computes the global configuration of the rope based on user interactions. Another component of the simulator precisely detects self-collisions in the rope as well as collisions with other objects. Finally, a third component manages collisions to prevent penetration, while making the rope slide with some friction along itself and other objects, so that knots can be pulled tight in a realistic manner. An additional module uses recent results from knot theory to identify, also in real time, which topological knots have been tied. This work was motivated by surgical suturing, but simulation in other domains, such as sailing and rock climbing, could also benefit from it. C1 Stanford Univ, Dept Comp Sci, Stanford, CA 94305 USA. Stanford NASA Natl Biocomputat Ctr, Stanford, CA 94305 USA. RP Stanford Univ, Dept Comp Sci, 353 Serra Mall, Stanford, CA 94305 USA. EM jbrown@cs.stanford.edu NR 41 TC 65 Z9 71 U1 0 U2 8 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0178-2789 EI 1432-2315 J9 VISUAL COMPUT JI Visual Comput. PD MAY PY 2004 VL 20 IS 2-3 BP 165 EP 179 DI 10.1007/s00371-003-0226-y PG 15 WC Computer Science, Software Engineering SC Computer Science GA 818ZV UT WOS:000221283900006 ER PT J AU Fast, KE Kostiuk, T Espenak, F Livengood, TA Hewagama, T A'Hearn, MF AF Fast, KE Kostiuk, T Espenak, F Livengood, TA Hewagama, T A'Hearn, MF TI Stratospheric ozone profiles from Mauna Kea, Hawai'i (19.8 degrees N, 155.5 degrees W) using infrared heterodyne spectroscopy, 1988-2003 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TUNABLE DIODE-LASER; SPECTROMETER; SPECTROPHOTOMETRY; TEMPERATURE; ABUNDANCE; ETHANE; LOA AB We present stratospheric ozone abundance profiles retrieved from absorption spectroscopy of the atmosphere backlit by thermal continuum emission of the Moon. Infrared heterodyne spectra at 9.6 mum at a resolving power of lambda/Deltalambda greater than or equal to 10 6 have been acquired on many occasions between 1988 and 2003 from the NASA Infrared Telescope Facility on Mauna Kea, Hawai'i. IR heterodyne spectroscopy provides a passive probe of terrestrial ozone distribution in the 25-50 km region of the stratosphere with the potential to retrieve altitude-resolved profiles of temperature and abundance. Retrieved ozone profiles are compared with those obtained nearby using active and in situ means (lidar, ozonesonde) with good agreement (less than or equal to0.1 ppmv) in the lower stratosphere and with differences ranging from 0 to 1 ppmv in the upper stratosphere. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Challenger Ctr Space Educ, Alexandria, VA 22314 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Fast, KE (reprint author), NASA, Goddard Space Flight Ctr, Code 693, Greenbelt, MD 20771 USA. EM kelly.e.fast@nasa.gov RI Hewagama, T/C-8488-2012; Livengood, Timothy/C-8512-2012; Kostiuk, Theodor/A-3077-2014 NR 21 TC 4 Z9 4 U1 2 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 30 PY 2004 VL 31 IS 8 AR L08109 DI 10.1029/2004GL019443 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 819OP UT WOS:000221324800002 ER PT J AU Mendillo, M Pi, XQ Smith, S Martinis, C Wilson, J Hinson, D AF Mendillo, M Pi, XQ Smith, S Martinis, C Wilson, J Hinson, D TI Ionospheric effects upon a satellite navigation system at Mars SO RADIO SCIENCE LA English DT Article DE ionosphere; satellite navigation; Mars ID RADIO OCCULTATION MEASUREMENTS; SOLAR-WIND INTERACTION; GLOBAL SURVEYOR; MARTIAN IONOSPHERE; SLAB THICKNESS; ATMOSPHERE; VARIABILITY; WAVES; MODEL; LAYER AB [1] Trans-ionospheric radio propagation effects resulting in ranging errors are examined for a potential orbital network of communications and navigational satellites at Mars. Using recent results from the radio science experiment on board the Mars Global Surveyor (MGS) spacecraft and a photochemical model of Mars' ionosphere, we study the total electron content (TEC) at Mars to investigate how its latitude, local time, and solar cycle patterns would contribute to errors in positioning on the planet. In addition, we examine the relationship between TEC and peak density (N-max) and find that their ratio, called the equivalent slab thickness, shows that integral preserving distortions of the Ne( h) profile can be rather substantial, implying that neutral atmosphere dynamics can have strong effects upon Mars' photochemical ionosphere. We use MGS observations to validate modeling results and determine the extreme cases for TEC at Mars (i.e., when the planet is at perihelion during solar maximum years and at aphelion during solar minimum years). If a proposed Mars Communication and Navigation (MC&N) System used UHF/L-band (1-2 GHz) transmission frequencies similar to those used for the terrestrial Global Positioning System (GPS) satellites, upper limits to the magnitude and variability of the martian ionosphere (TEC < &SIM;few x 10(16) el m(-2), with σ &SIM; 10%) would not be of concern unless extremely precise positional information were required (< 1 m). The impact of the ionosphere would be greater along slanted ray paths, and especially if lower frequency UHF beacon frequencies (e. g., 400 MHz) were selected for use. Indeed, such effects could be used as a diagnostic for the global structure of Mars' ionosphere, much in the same way as GPS measurements are used in terrestrial ionospheric physics. C1 Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Stanford Univ, Dept Elect Engn, Stanford, CA 94305 USA. RP Mendillo, M (reprint author), Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. EM mendillo@bu.edu RI Mendillo, Michael /H-4397-2014 NR 31 TC 19 Z9 19 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 APR 30 PY 2004 VL 39 IS 2 AR RS2028 DI 10.1029/2003RS002933 PG 11 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 819PM UT WOS:000221327100004 ER PT J AU Siqueira, P Chapman, B McGarragh, G AF Siqueira, P Chapman, B McGarragh, G TI The coregistration, calibration, and interpretation of multiseason JERS-1 SAR data over South America (vol 87, pg 389, 2003) SO REMOTE SENSING OF ENVIRONMENT LA English DT Correction ID SYNTHETIC-APERTURE RADAR; SIR-C/X-SAR; AMAZON BASIN; SATELLITE DATA; DEFORESTATION; VALIDATION; VEGETATION; MICHIGAN; MOSAICS; CARBON AB The Large-Scale Biosphere-Atmosphere (LBA) experiment in Amazonia represents a unique opportunity to make a comprehensive study of the Amazon region and its component ecosystems. To make sense of the field studies and to generalize the results from them, remote sensing techniques and comprehensive mapping are critical elements for producing region-wide science results. In this paper, we present the processing work done for one such mapping campaign, that of the JERS-1 L-band two season (low and high-flood) SAR data collected in 1995 and 1996. Specifically, to make a useable resource for other LBA researchers to explore, the datasets from the two seasons had to be coregistered (to a sub-pixel level), radiometrically calibrated, and interpreted to verify the quality of the data. This paper describes the techniques used to achieve these goals and an estimate of the land cover based on a simple classification of the data. (C) 2004 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Siqueira, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Siqueira, Paul/D-9760-2016 OI Siqueira, Paul/0000-0001-5781-8282 NR 31 TC 0 Z9 0 U1 0 U2 3 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 APR 30 PY 2004 VL 90 IS 4 BP 535 EP 550 DI 10.1016/j.rse.2004.03.004 PG 16 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 819IQ UT WOS:000221309000011 ER PT J AU Fridlind, AM Ackerman, AS Jensen, EJ Heymsfield, AJ Poellot, MR Stevens, DE Wang, DH Miloshevich, LM Baumgardner, D Lawson, RP Wilson, JC Flagan, RC Seinfeld, JH Jonsson, HH VanReken, TM Varutbangkul, V Rissman, TA AF Fridlind, AM Ackerman, AS Jensen, EJ Heymsfield, AJ Poellot, MR Stevens, DE Wang, DH Miloshevich, LM Baumgardner, D Lawson, RP Wilson, JC Flagan, RC Seinfeld, JH Jonsson, HH VanReken, TM Varutbangkul, V Rissman, TA TI Evidence for the predominance of mid-tropospheric aerosols as subtropical anvil cloud nuclei SO SCIENCE LA English DT Article ID TROPICAL CUMULONIMBUS; CIRRUS CLOUDS; MODEL; SIZE; MICROPHYSICS; CONVECTION; POLLUTION; EVOLUTION; CLIMATE; RAIN AB NASA's recent Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment focused on anvil cirrus clouds, an important but poorly understood element of our climate system. The data obtained included the first comprehensive measurements of aerosols and cloud particles throughout the atmospheric column during the evolution of multiple deep convective storm systems. Coupling these new measurements with detailed cloud simulations that resolve the size distributions of aerosols and cloud particles, we found several lines of evidence indicating that most anvil crystals form on mid-tropospheric rather than boundary-layer aerosols. This result defies conventional wisdom and suggests that distant pollution sources may have a greater effect on anvil clouds than do local sources. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ N Dakota, Dept Atmospher Sci, Grand Forks, ND 58202 USA. Lawrence Livermore Natl Lab, Livermore, CA 94552 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Nacl Autonoma Mexico, Ctr Ciencias Atmosfera, Mexico City 04510, DF, Mexico. Stratton Pk Engn Co Inc, Boulder, CO 80301 USA. Univ Denver, Dept Engn, Denver, CO 80208 USA. CALTECH, Dept Chem & Chem Engn, Pasadena, CA 91125 USA. Ctr Interdisciplinary Remotely Piloted Aircraft S, Marina, CA 93933 USA. RP Fridlind, AM (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM ann.fridlind@nasa.gov RI Heymsfield, Andrew/E-7340-2011; Ackerman, Andrew/D-4433-2012; Fridlind, Ann/E-1495-2012 OI Ackerman, Andrew/0000-0003-0254-6253; NR 34 TC 72 Z9 78 U1 3 U2 9 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD APR 30 PY 2004 VL 304 IS 5671 BP 718 EP 722 DI 10.1126/science.1094947 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 816JD UT WOS:000221105300040 PM 15118158 ER PT J AU Jenet, FA Ransom, SM AF Jenet, FA Ransom, SM TI The geometry of the double-pulsar system J0737-3039 from systematic intensity variations SO NATURE LA English DT Article ID PRECESSION; B1913+16 AB Two pulsars (PSR J0737 - 3039A(1) and B-2) were recently discovered in highly relativistic orbits around one another. The system contains a rapidly rotating pulsar with a spin period of 22.7 ms and a slow companion with a spin period of 2.77 s, referred to here as 'A' and 'B', respectively. A unique property of the system is that the pulsed radio flux from B increases systematically by almost two orders of magnitude during two short portions of its orbit(2). Here we report a geometrical model of the system that simultaneously explains the intensity variations of B and provides constraints on the spin axis orientation and emission geometry of A. Our model assumes that B's pulsed radio flux increases when illuminated by emission from A. We predict that A's pulse profile will evolve considerably over the next several years owing to geodetic precession until it disappears entirely in 15 - 20 years. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada. MIT, Ctr Space Res, Cambridge, MA 02139 USA. RP Jenet, FA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM merlyn@alum.mit.edu OI Ransom, Scott/0000-0001-5799-9714 NR 14 TC 26 Z9 27 U1 0 U2 0 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 29 PY 2004 VL 428 IS 6986 BP 919 EP 921 DI 10.1038/nature02509 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 816AO UT WOS:000221083000033 PM 15118719 ER PT J AU Cede, A Luccini, E Nunez, L Piacentini, RD Blumthaler, M Herman, JR AF Cede, A Luccini, E Nunez, L Piacentini, RD Blumthaler, M Herman, JR TI TOMS-derived erythemal irradiance versus measurements at the stations of the Argentine UV Monitoring Network SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE erythemal irradiance; satellite-derived data; ground-based measurements ID SURFACE UV; TOTAL OZONE; SATELLITE ESTIMATION; ULTRAVIOLET-RADIATION; RETRIEVALS; REFLECTIVITY; CLIMATOLOGY; ALGORITHM; MODEL; NM AB [1] The major factors causing differences between satellite-derived and ground-based ultraviolet (UV) erythemal irradiances and doses are discussed. Measurements totaling more than 4700 days during 1997-1999 were obtained at 8 stations (22degreesS-64degreesS) of the Argentine UV Monitoring Network. The satellite retrieval uses radiative transfer calculations for cloud- and aerosol-free conditions multiplied by correction factors for clouds and aerosols. Key parameters are total ozone, cloud optical depth, and surface albedo derived from Total Ozone Mapping Spectrometer ( TOMS). When no aerosol correction is applied, systematic differences of satellite-derived erythemal irradiance relative to ground-based measurements amount to +1% at a tropical high-altitude Andean location, +10% at stations in the central Pampas, +5% at southern Patagonian sites, and -7% at the southernmost continental and Antarctic stations with varying snow cover. When an aerosol correction is applied by estimating "minimum'' and "maximum'' aerosol loading, the systematic differences are within +/-10% for all "snow-free'' stations. To reduce the differences at places with varying snow conditions, an "average surface-albedo climatology'' must be used instead the TOMS climatology of minimum albedo. Although the statistical uncertainty of the differences increases with TOMS reflectivity, the systematic difference is independent of TOMS reflectivity for most of the stations, so on average the comparison for cloudy situations is as good as for clear-sky conditions. The comparison for daily erythemal doses gives similar results with smaller statistical uncertainty. Measured uncertainties are in agreement with a theoretical analysis. For most locations, well-characterized ground-based instruments should agree with TOMS satellite estimations within 10% if aerosol corrections are known. C1 Sci Syst & Applicat Inc, Lanham, MD USA. Univ Nacl Rosario, CONICET, Inst Fis Rosario, Rosario, Argentina. Univ Nacl Rosario, Fac Ciencias Exactas Ingn & Agrimensura, Rosario, Argentina. Univ Innsbruck, Inst Med Phys, A-6020 Innsbruck, Austria. RP Cede, A (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM cede@gsfc.nasa.gov OI Herman, Jay/0000-0002-9146-1632 NR 27 TC 19 Z9 21 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 APR 27 PY 2004 VL 109 IS D8 AR D08109 DI 10.1029/2004JD004519 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 819OR UT WOS:000221325000007 ER PT J AU Popp, PJ Gao, RS Marcy, TP Fahey, DW Hudson, PK Thompson, TL Karcher, B Ridley, BA Weinheimer, AJ Knapp, DJ Montzka, DD Baumgardner, D Garrett, TJ Weinstock, EM Smith, JB Sayres, DS Pittman, JV Dhaniyala, S Bui, TP Mahoney, MJ AF Popp, PJ Gao, RS Marcy, TP Fahey, DW Hudson, PK Thompson, TL Karcher, B Ridley, BA Weinheimer, AJ Knapp, DJ Montzka, DD Baumgardner, D Garrett, TJ Weinstock, EM Smith, JB Sayres, DS Pittman, JV Dhaniyala, S Bui, TP Mahoney, MJ TI Nitric acid uptake on subtropical cirrus cloud particles (vol 109, art no D06302, 2004) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Correction C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO USA. Deutsch Zentrum Luft & Raumfahrt Oberpfaffenfofen, Inst Phys Atmosphare, Wessling, Germany. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Univ Nacl Autonoma Mexico, Ctr Ciencias Atmosfera, Mexico City, DF, Mexico. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. Harvard Univ, Atmospher Res Project, Cambridge, MA USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Popp, PJ (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. RI Gao, Ru-Shan/H-7455-2013; Karcher, Bernd/D-5325-2014; Fahey, David/G-4499-2013 OI Karcher, Bernd/0000-0003-0278-4980; Fahey, David/0000-0003-1720-0634 NR 1 TC 2 Z9 2 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 APR 27 PY 2004 VL 109 IS D8 AR D08306 DI 10.1029/2004JD004781 PG 1 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 819OR UT WOS:000221325000008 ER PT J AU Russell, PB Livingston, JM Dubovik, O Ramirez, SA Wang, J Redemann, J Schmid, B Box, M Holben, BN AF Russell, PB Livingston, JM Dubovik, O Ramirez, SA Wang, J Redemann, J Schmid, B Box, M Holben, BN TI Sunlight transmission through desert dust and marine aerosols: Diffuse light corrections to Sun photometry and pyrheliometry SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE Sun photometer; aerosol; diffuse ID OPTICAL-DEPTH SPECTRA; SAHARAN DUST; ACE-ASIA; COLUMN CLOSURE; WATER-VAPOR; TROPOSPHERIC AEROSOL; SIZE DISTRIBUTION; MINERAL AEROSOLS; SULFATE AEROSOL; SOLAR SPECTRUM AB [1] Desert dust and marine aerosols are receiving increased scientific attention because of their prevalence on intercontinental scales and their potentially large effects on Earth radiation, climate, other aerosols, clouds, and precipitation. The relatively large size of dust and marine aerosol particles produces scattering phase functions that are strongly forward peaked. Hence Sun photometry and pyrheliometry of these aerosols are more subject to diffuse light errors than is the case for smaller aerosols. We quantify these diffuse light effects for common Sun photometer and pyrheliometer fields of view (FOV), using data on dust and marine aerosols from ( 1) Aerosol Robotic Network (AERONET) measurements of sky radiance and solar beam transmission and ( 2) in situ measurements of aerosol layer size distribution and chemical composition. Accounting for particle nonsphericity is important when deriving dust size distribution from both AERONET and in situ aerodynamic measurements. We obtain correction factors that can be applied to Sun photometer or pyrheliometer results for aerosol optical depth (AOD) or direct beam transmission. The corrections are negligible (less than similar to1% of AOD) for Sun photometers with narrow FOV (half-angle eta < similar to 1 degrees), but they can be as large as 10% of AOD at 354 nm wavelength for Sun photometers with eta = 1.85 degrees. For pyrheliometers (which can have eta up to similar to 2.8 degrees), corrections can be as large as 16% at 354 nm. AOD correction factors are well correlated with AOD wavelength dependence (hence angstrom ngstrom exponent). We provide best fit equations for determining correction factors from angstrom ngstrom exponents of uncorrected AOD spectra, and we demonstrate their application to vertical profiles of multiwavelength AOD. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SRI Int, Menlo Pk, CA 94025 USA. NASA, Goddard Space Flight Ctr, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. Bay Area Environm Res Inst, Sonoma, CA USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ New S Wales, Sch Phys, Sydney, NSW, Australia. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Russell, PB (reprint author), NASA, Ames Res Ctr, MS 245-5, Moffett Field, CA 94035 USA. EM philip.b.russell@nasa.gov; jlivingston@mail.arc.nasa.gov; dubovik@aeronet.gsfc.nasa.gov; s.a.ramirez@mail.arc.nasa.gov; jian@bnl.gov; jredemann@mail.arc.nasa.gov; bschmid@mail.arc.nasa.gov; m.box@unsw.edu.au; brent@aeronet.gsfc.nasa.gov RI Dubovik, Oleg/A-8235-2009; Wang, Jian/G-9344-2011 OI Dubovik, Oleg/0000-0003-3482-6460; NR 49 TC 22 Z9 22 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 27 PY 2004 VL 109 IS D8 AR D08207 DI 10.1029/2003JD004292 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 819OR UT WOS:000221325000003 ER PT J AU Sun, CJ Walker, JP Houser, PR AF Sun, CJ Walker, JP Houser, PR TI A methodology for snow data assimilation in a land surface model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE snow assimilation; extended Kalman filter; GCM initialization ID CATCHMENT-BASED APPROACH; CIRCULATION MODEL; NORTHERN-HEMISPHERE; ALTIMETER DATA; FORECAST BIAS; KALMAN FILTER; SOIL-MOISTURE; CLIMATE MODEL; PART I; COVER AB [1] Snow cover has a large influence on heat fluxes between the land and atmosphere because of its high albedo and insulating thermal properties. Hence accurate snow representation in coupled land-ocean-atmosphere global climate models has the potential to greatly increase prediction accuracy. To this end, a one-dimensional extended Kalman filter analysis scheme has been developed to assimilate observed snow water equivalent into the NASA Seasonal-to-Interannual Prediction Project (NSIPP) catchment-based land surface model. This study presents the results from a set of data assimilation "twin'' experiments using an uncoupled version of the land surface model. First, "true'' snow states are generated by spinning-up the land surface model for 1987 using an observation-constrained version of the European Centre for Medium-Range Weather Forecasts (ECMWF) 15-year Re-Analysis (ERA-15) data set for atmospheric forcing. A degraded 1987 simulation was then made by initializing the model with no snow on 1 January 1987. A third simulation assimilated the synthetically generated snow water equivalent "observations'' from the true simulation into the degraded simulation once a day. This study illustrates that by assimilating snow water equivalent observations, which are readily available from remote sensing satellites, other state variables (i.e., snow depth and temperature) can be retrieved and effects of poor initial conditions removed. Runoff and atmospheric flux predictions are also improved. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD USA. Univ Melbourne, Dept Civil & Environm Engn, Parkville, Vic, Australia. RP Sun, CJ (reprint author), NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Code 900 3, Greenbelt, MD 20771 USA. EM csun@janus.gsfc.nasa.gov RI Sun, Chaojiao/A-9569-2011; Walker, Jeffrey/D-2624-2009; Houser, Paul/J-9515-2013 OI Sun, Chaojiao/0000-0002-7030-0485; Houser, Paul/0000-0002-2991-0441 NR 43 TC 42 Z9 43 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 27 PY 2004 VL 109 IS D8 AR D08108 DI 10.1029/2003JD003765 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 819OR UT WOS:000221325000002 ER PT J AU Milan, SE Cowley, SWH Lester, M Wright, DM Slavin, JA Fillingim, M Carlson, CW Singer, HJ AF Milan, SE Cowley, SWH Lester, M Wright, DM Slavin, JA Fillingim, M Carlson, CW Singer, HJ TI Response of the magnetotail to changes in the open flux content of the magnetosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE magnetosphere; magnetotail; solar-terrestrial coupling; substorms ID INTERPLANETARY MAGNETIC-FIELD; DISTANT MAGNETOTAIL; SOLAR-WIND; GEOMAGNETIC TAIL; TIME VARIATIONS; NEAR-EARTH; SUBSTORM; MAGNETOPAUSE; CONVECTION; BOUNDARY AB [1] We compare the open flux content of the magnetosphere, quantified by measurements of the size of the northern ionospheric polar cap, with the radius of the magnetotail at X approximate to - 25 R-E, deduced from observations made by the IMP-8 spacecraft. During an 8-hour period of observation we estimate that the proportion of terrestrial flux that is interconnected with the solar wind varies between 12 and 2.5%. This latter extreme, representing an almost closed magnetosphere, follows the incidence of a solar wind dynamic pressure step, the onset of a large substorm, and a 3-hour period of northward IMF. The deflated and compressed magnetotail is predicted to have a radius as small as 12 R-E at this time. The magnetotail does not reinflate to more typical dimensions until some time after a southward turning of the IMF, leading to accumulation of open flux through low latitude reconnection. We compare our observations with estimates of the shape of the magnetopause from an empirical model. We also present a simple model of the varying length of the magnetotail, based on upstream solar wind conditions, and observations of the size of the polar cap. C1 Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Space Environm Ctr, Boulder, CO 80303 USA. RP Milan, SE (reprint author), Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. EM steve.milan@ion.le.ac.uk; s.cowley@ion.le.ac.uk; m.lester@ion.le.ac.uk; d.wright@ion.le.ac.uk; jim.slavin@gsfc.nasa.gov; matt@ssl.berkeley.edu; cwc@ssl.berkeley.edu; howard.singer@noaa.gov RI Slavin, James/H-3170-2012 OI Slavin, James/0000-0002-9206-724X NR 37 TC 64 Z9 64 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 APR 24 PY 2004 VL 109 IS A4 AR A04220 DI 10.1029/2003JA010350 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 816CK UT WOS:000221087800005 ER PT J AU Black, GJ Campbell, DB Carter, LM Ostro, SJ AF Black, GJ Campbell, DB Carter, LM Ostro, SJ TI Radar detection of Iapetus SO SCIENCE LA English DT Article ID DARK SIDE; SPECTROPHOTOMETRY; SATELLITES C1 Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. Cornell Univ, Natl Astron & Ionosphere Ctr, Ithaca, NY 14853 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Black, GJ (reprint author), Univ Virginia, Dept Astron, POB 3818, Charlottesville, VA 22903 USA. EM gblack@virginia.edu RI Carter, Lynn/D-2937-2012 NR 13 TC 18 Z9 18 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD APR 23 PY 2004 VL 304 IS 5670 BP 553 EP 553 DI 10.1126/science.1096470 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 814LB UT WOS:000220975100038 PM 15105493 ER PT J AU Hakkinen, S Rhines, PB AF Hakkinen, S Rhines, PB TI Decline of subpolar North Atlantic circulation during the 1990s SO SCIENCE LA English DT Article ID DECADAL VARIABILITY; OCEAN; OSCILLATION; TOPEX/POSEIDON; TRANSPORT; MODEL; WATER; DEPTH; GYRE AB Observations of sea surface height reveal that substantial changes have occurred over the past decade in the mid- to high-latitude North Atlantic Ocean. TOPEX/Poseidon altimeter data show that subpolar sea surface height increased during the 1990s, and the geostrophic velocity derived from altimeter data exhibits declining subpolar gyre circulation. Combining the data from earlier satellites, we find that subpolar circulation may have been weaker in the late 1990s than in the late 1970s and 1980s. Direct current-meter observations in the boundary current of the Labrador Sea support the weakening circulation trend of the 1990s and, together with hydrographic data, show that the mid- to late 1990s decline extends deep in the water column. Analysis of the local surface forcing suggests that the 1990s buoyancy forcing has a dynamic effect consistent with altimetric and hydrographic observations: A weak thermohaline forcing allows the decay of the domed structure of subpolar isopycnals and weakening of circulation. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Washington, Seattle, WA 98195 USA. RP Hakkinen, S (reprint author), NASA, Goddard Space Flight Ctr, Code 971, Greenbelt, MD 20771 USA. EM sirpa.hakkinen@nasa.gov RI Hakkinen, Sirpa/E-1461-2012 NR 24 TC 315 Z9 323 U1 3 U2 51 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD APR 23 PY 2004 VL 304 IS 5670 BP 555 EP 559 DI 10.1126/science.1094917 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 814LB UT WOS:000220975100040 PM 15087505 ER PT J AU Bauschlicher, CW Lawson, JW Ricca, A Xue, YQ Ratner, MA AF Bauschlicher, CW Lawson, JW Ricca, A Xue, YQ Ratner, MA TI Current-voltage curves for molecular junctions: the effect of Cl substituents and basis set composition SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ELECTRONIC DEVICES; TRANSPORT; ATOMS; POTENTIALS; FORMALISM; EXCHANGE; ENERGY AB Current-voltage characteristics of gold-benzene-1,4-dithiol-gold junctions are calculated using a combined density functional theory/non-equilibrium Green's functions approach with local atomic basis sets. Improving the basis set with the addition of polarization or diffuse functions has some effect on the computed I-V curves, but even the small valence double zeta sets yield reasonable results. The results obtained using the hybrid B3LYP functional give slightly smaller conductance than those obtained using the pure BPW91 approach. Substituting Cl for H on the bridging molecule has only a small effect on the I-V curves. (C) 2004 Elsevier B.V. All rights reserved. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Space Technol Div, Moffett Field, CA 94035 USA. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. Northwestern Univ, Ctr Mat Res, Evanston, IL 60208 USA. RP Bauschlicher, CW (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Space Technol Div, Mail Stop 230-3, Moffett Field, CA 94035 USA. EM bauschli@pegasus.arc.nasa.gov NR 22 TC 29 Z9 29 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD APR 21 PY 2004 VL 388 IS 4-6 BP 427 EP 429 DI 10.1016/j.cplett.2004.03.038 PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 813VW UT WOS:000220935600037 ER PT J AU Llope, W Geurts, F Mitchell, JW Liu, Z Adams, N Eppley, G Keane, D Li, J Liu, F Mutchler, GS Nussbaum, T Bonner, B Sappenfield, P Zhang, B Zhang, WM AF Llope, W Geurts, F Mitchell, JW Liu, Z Adams, N Eppley, G Keane, D Li, J Liu, F Mutchler, GS Nussbaum, T Bonner, B Sappenfield, P Zhang, B Zhang, WM TI The TOFp/pVPD time-of-flight system for STAR SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE particle identification; time of flight; STAR ID SCINTILLATION-COUNTERS; LEADING-EDGE; DETECTOR; SPECTROMETER; RESOLUTION; SUBSYSTEM; TUBES AB A time-of-flight system was constructed for the STAR Experiment for the direct identification of hadrons produced in (197) An + (197) An collisions at RHIC. The system consists of two separate detector subsystems, one called the Pseudo Vertex Position Detector (pVPD, the "start" detector) and the other called the Time of Flight Patch (TOFp, the "stop" detector). Each detector is based on conventional scintillator/phototube technology and includes custom high-performance front-end electronics and a common CAMAC-based digitization and read-out. The design of the system and its performance during the 2001 RHIC run will be described. The start resolution attained by the pVPD was 24 ps, implying a pVPD single-detector resolution of 58 ps. The total time resolution of the system averaged over all detector channels was 87 ps, allowing direct pi/K/P discrimination for momenta up to similar to 1.8 GeV/c, and direct (pi + K)/p discrimination up to similar to 3 GeV/c. (C) 2004 Elsevier B.V. All rights reserved. C1 Rice Univ, TW Bonner Nucl Lab, Houston, TX 77005 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Huazhong Normal Univ, Dept Phys, Wuhan 430070, Peoples R China. Inst High Energy Phys, Beijing 100039, Peoples R China. Kent State Univ, Kent, OH 44242 USA. RP Llope, W (reprint author), Rice Univ, TW Bonner Nucl Lab, MS 315,6100 S Main St, Houston, TX 77005 USA. EM llope@physics.rice.edu NR 28 TC 40 Z9 40 U1 0 U2 0 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 APR 21 PY 2004 VL 522 IS 3 BP 252 EP 273 DI 10.1016/j.nima.2003.11.414 PG 22 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 816GL UT WOS:000221098300009 ER PT J AU Walther, JH Werder, T Jaffe, RL Gonnet, P Bergdorf, M Zimmerli, U Koumoutsakos, P AF Walther, JH Werder, T Jaffe, RL Gonnet, P Bergdorf, M Zimmerli, U Koumoutsakos, P TI Water-carbon interactions III: The influence of surface and fluid impurities SO PHYSICAL CHEMISTRY CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS SIMULATION; AQUEOUS NACL SOLUTION; ULTRAHIGH-VACUUM TECHNIQUES; SODIUM-CHLORIDE SOLUTIONS; ION-PAIRS; COMPUTER-SIMULATIONS; CONTACT ANGLES; HYDROGEN STORAGE; ATOMIC-HYDROGEN; MEAN FORCE AB Molecular dynamics. simulations are performed to study the influence of surface and fluid impurities on water-carbon interactions. In order to quantify these interactions we consider the canonical problem of wetting of a doped flat graphitic surface by a water system with impurities. As model fluid impurities we consider aqueous solutions of potassium-chloride with molar concentrations up to 1.8 M. Quantum chemistry calculations are performed to derive pair potentials for the ion-graphite interactions. The contact angle is found to decrease weakly with increasing ionic concentration, from 90degrees at 0 M to 81degrees at 1.8 M concentration. The influence of solid impurities is found to be more significant. Thus, 10, 15, and 20% coverages of chemisorbed hydrogen result in contact angles of 90degrees, 74degrees and 60degrees, respectively. C1 ETH, Inst Computat Sci, CH-8092 Zurich, Switzerland. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Walther, JH (reprint author), ETH, Inst Computat Sci, CH-8092 Zurich, Switzerland. EM walther@inf.ethz.ch; werder@inf.ethz.ch; rjaffe@mail.arc.nasa.gov; gonnetp@inf.ethz.ch; bergdorf@inf.ethz.ch; zimmerli@inf.ethz.ch; petros@inf.ethz.ch RI Gonnet, Pedro/A-6935-2008; Koumoutsakos, Petros/A-2846-2008; Walther, Jens/D-9549-2015 OI Gonnet, Pedro/0000-0003-4509-7291; Koumoutsakos, Petros/0000-0001-8337-2122; Walther, Jens/0000-0001-8100-9178 NR 74 TC 24 Z9 24 U1 0 U2 13 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 1463-9076 J9 PHYS CHEM CHEM PHYS JI Phys. Chem. Chem. Phys. PD APR 21 PY 2004 VL 6 IS 8 BP 1988 EP 1995 DI 10.1039/b312740k PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 821JB UT WOS:000221455200051 ER PT J AU Zhang, ZB Yang, P Kattawar, GW Tsay, SC Baum, BA Hu, YX Heymsfield, AJ Reichardt, J AF Zhang, ZB Yang, P Kattawar, GW Tsay, SC Baum, BA Hu, YX Heymsfield, AJ Reichardt, J TI Geometrical-optics solution to light scattering by droxtal ice crystals SO APPLIED OPTICS LA English DT Article ID SUPERCOOLED LIQUID WATER; DIFFERENCE TIME-DOMAIN; SINGLE-SCATTERING; CIRRUS CLOUDS; BIDIRECTIONAL REFLECTANCE; PHASE; DISTRIBUTIONS; SENSITIVITY; MATRIX; SHAPE AB We investigate the phase matrices of droxtals at wavelengths of 0.66 and 11 mum by using an improved geometrical-optics method. An efficient method is developed to specify the incident rays and the corresponding impinging points on the particle surface necessary to initialize the ray-tracing computations. At the 0.66-mum wavelength, the optical properties of droxtals are different from those of hexagonal ice crystals. At the 11-mum wavelength, the phase functions for droxtals are essentially featureless because of strong absorption within the particles, except for ripple structures that are caused by the phase interference of the diffracted wave. (C) 2004 Optical Society of America. 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 Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Deutsch Wetterdienst, Meteorol Observ, D-15848 Lindenberg, Tauche, Germany. RP Zhang, ZB (reprint author), Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. EM pyang@ariel.met.tamu.edu RI Zhang, Zhibo/D-1710-2010; Yang, Ping/B-4590-2011; Baum, Bryan/B-7670-2011; Heymsfield, Andrew/E-7340-2011; Tsay, Si-Chee/J-1147-2014; Hu, Yongxiang/K-4426-2012 OI Zhang, Zhibo/0000-0001-9491-1654; Baum, Bryan/0000-0002-7193-2767; NR 43 TC 45 Z9 46 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 APR 20 PY 2004 VL 43 IS 12 BP 2490 EP 2499 DI 10.1364/AO.43.002490 PG 10 WC Optics SC Optics GA 813BN UT WOS:000220882700014 PM 15119619 ER PT J AU Pounds, KA Reeves, JN Page, KL O'Brien, PT AF Pounds, KA Reeves, JN Page, KL O'Brien, PT TI An XMM-Newton observation of the Seyfert 1 galaxy 1H 0419-577 in an extreme low state SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (1H 0419-577, LB 1727); galaxies : Seyfert; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; VELOCITY IONIZED OUTFLOW; ALL-SKY SURVEY; X-RAY-SPECTRA; BLACK-HOLE; LINE; DISK; MCG-6-30-15; REFLECTION; MODELS AB Previous observations of the luminous Seyfert 1 galaxy 1H 0419-577 have found its X-ray spectrum to range from that of a typical Seyfert 1 galaxy with a 2-10 keV power-law index of Gamma similar to 1.9 to a much flatter power law of Gamma similar to 1.5 or less. We report here a new XMM-Newton observation that allows the low-state spectrum to be studied in much greater detail than hitherto. We find a very hard spectrum (Gamma similar to 1.0), which exhibits broad features that can be modeled with the addition of an extreme relativistic Fe K emission line or with partial covering of the underlying continuum by a substantial column density of near-neutral gas. Both the EPIC and Reflection Grating Spectrometer (RGS) data show evidence for strong line emission of O VII and O VIII requiring an extended region of low-density photoionized gas in 1H 0419-577. Comparison with an earlier XMM-Newton observation when 1H 0419-577 was "X-ray-bright" indicates that the dominant spectral variability occurs via a steep power-law component. C1 Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD USA. RP Pounds, KA (reprint author), Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. EM kap@star.le.ac.uk NR 36 TC 26 Z9 26 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2004 VL 605 IS 2 BP 670 EP 676 DI 10.1086/382678 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WL UT WOS:000220801900012 ER PT J AU Rubin, RH Ferland, GJ Chollet, EE Horstmeyer, R AF Rubin, RH Ferland, GJ Chollet, EE Horstmeyer, R TI C-12/C-13 ratio in planetary nebulae from the IUE archives SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic processes; ISM : abundances; planetary nebulae : general; planetary nebulae : individual (NGC 2440); stars : abundances; stars : AGB and post-AGB ID DEEP CIRCULATION; RED GIANTS; C-III; GASEOUS NEBULAE; CARBON STARS; MASS STARS; EXCITATION; TRANSITIONS; ABUNDANCES; EVOLUTION AB We investigated the abundance ratio of C-12/C-13 in planetary nebulae by examining emission lines arising from C III 2s2p P-3(2,1,0)o --> 2s(2) S-1(0). Spectra were retrieved from the International Ultraviolet Explorer archives, and multiple spectra of the same object were co-added to achieve improved signal-to-noise ratio. The C-13 hyperfine structure line at 1909.6 Angstrom was detected in NGC 2440. The C-12/C-13 ratio was found to be similar to 4.4 +/- 1.2. In all other objects, we provide an upper limit for the flux of the 1910 Angstrom line. For 23 of these sources, a lower limit for the C-12/C-13 ratio was established. The impact on our current understanding of stellar evolution is discussed. The resulting high-signal-to-noise ratio C III spectrum helps constrain the atomic physics of the line formation process. Some objects have the measured 1907/1909 Angstrom flux ratio outside the low - electron density theoretical limit for C-12. A mixture of C-13 with C-12 helps to close the gap somewhat. Nevertheless, some observed 1907/1909 Angstrom flux ratios still appear too high to conform to the currently predicted limits. It is shown that this limit, as well as the 1910/1909 Angstrom flux ratio, are predominantly influenced by using the standard partitioning among the collision strengths for the multiplet S-1(0) - P-3(J)o according to the statistical weights. A detailed calculation for the fine-structure collision strengths between these individual levels would be valuable. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Orion Enterprises, Moffett Field, CA 94035 USA. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. RP Rubin, RH (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM rubin@cygnus.arc.nasa.gov; gary@pa.uky.edu OI Ferland, Gary/0000-0003-4503-6333 NR 29 TC 19 Z9 19 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2004 VL 605 IS 2 BP 784 EP 792 DI 10.1086/382528 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WL UT WOS:000220801900022 ER PT J AU Lin, JR Zhang, SN Li, TP AF Lin, JR Zhang, SN Li, TP TI Gamma-ray bursts are produced predominately in the early universe SO ASTROPHYSICAL JOURNAL LA English DT Article DE early universe; gamma rays : bursts; stars : formation ID ENERGY RESERVOIR; TIME DILATION; LUMINOSITY; REDSHIFTS; EMISSION; DISCOVERY; EVOLUTION; GALAXIES; CATALOG; LINES AB It is known that some observed gamma-ray bursts (GRBs) are produced at cosmological distances and that the GRB production rate may follow the star formation rate. We model the BATSE-detected intensity distribution of long GRBs in order to determine their space density distribution and opening angle distribution. Our main results are: the lower and upper distance limits to the GRB production are z approximate to 0.24 and > 10, respectively; the GRB opening angle follows an exponential distribution and the mean opening angle is about 0.03 radians; and the peak luminosity appears to be a better standard candle than the total energy of a GRB. C1 Tsinghua Univ, Tsinghua Ctr Astrophys, Beijing 100084, Peoples R China. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. NASA, Space Sci Lab, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Chinese Acad Sci, Inst High Energy Phys, Beijing, Peoples R China. RP Zhang, SN (reprint author), Tsinghua Univ, Tsinghua Ctr Astrophys, Beijing 100084, Peoples R China. EM zhangsn@tsinghua.edu.cn NR 32 TC 21 Z9 21 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2004 VL 605 IS 2 BP 819 EP 822 DI 10.1086/382503 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WL UT WOS:000220801900025 ER PT J AU Cliver, EW Kahler, SW Reames, DV AF Cliver, EW Kahler, SW Reames, DV TI Coronal shocks and solar energetic proton events SO ASTROPHYSICAL JOURNAL LA English DT Article DE shock waves; Sun : corona; Sun : particle emission; Sun : radio radiation ID II RADIO-BURSTS; X-RAY EVENTS; MASS EJECTIONS; PARTICLE EVENTS; ELECTRON EVENTS; 1 AU; WIND SPACECRAFT; FLARE ELECTRONS; MAGNETIC-FIELD; ACCELERATION AB From 1996 July through 2001 June, less than half (43/98) of all favorably located (from solar western hemisphere sources) metric type II radio bursts were associated with solar energetic proton (SEP) events observed at Earth. When western hemisphere metric type IIs were accompanied by decametric-hectometric (DH; 1 - 14 MHz) type II emission (observed by Wind/WAVES) during this period, their association with similar to20 MeV SEP events (with peak fluxes greater than or equal to 10(-3) protons cm(-2) s(-1) sr(-1) MeV-1) was 90% (26/29), versus only 25% (17/69) for metric IIs without a DH counterpart. Overall, 82% (63%) of all SEP events with visible disk origins were associated with metric (DH) type II bursts, with the percentage associations increasing with SEP event size to 88% (96%) for similar to20 MeV SEP events with peak intensities of greater than or equal to10(-1) protons cm(-2) s(-1) sr(-1) MeV-1. Our results are consistent with the following possibilities (which are not mutually exclusive): (1) large similar to20 MeV SEP events result from strong shocks that are capable of persisting well beyond similar to3 R-. (the nominal 14 MHz plasma level); (2) shock acceleration is most efficient above similar to3 R-.; and (3) shocks that survive beyond similar to3 R-. are more likely to have broad longitudinal extents, enabling less well connected shocks to intercept open field lines connecting to Earth. C1 USAF, Space Vehicles Directorate, Res Lab, Hanscom AFB, MA 01731 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Cliver, EW (reprint author), USAF, Space Vehicles Directorate, Res Lab, Hanscom AFB, MA 01731 USA. EM edward.cliver@hanscom.af.mil; stephen.kahler@hanscom.af.mil; reames@milkyway.gsfc.nasa.gov NR 94 TC 103 Z9 106 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2004 VL 605 IS 2 BP 902 EP 910 DI 10.1086/382651 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WL UT WOS:000220801900035 ER PT J AU Phillips, KJH AF Phillips, KJH TI The solar flare 3.8-10 keV X-ray spectrum SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : flares; Sun : X-rays, gamma rays ID DIELECTRONIC SATELLITE SPECTRA; ELECTRON-IMPACT EXCITATION; INNER-SHELL TRANSITIONS; HELIUM-LIKE IONS; HIGHLY IONIZED IRON; RATE COEFFICIENTS; LINE EMISSION; FE-XXV; IONIZATION EQUILIBRIUM; PHOTOSPHERIC IRON AB The 3.8 - 10 keV solar flare spectrum includes lines of highly stripped Ca, Fe, and Ni ions, as well as a continuum steeply falling with energy. Groups of lines at similar to7 and similar to8 keV, observed during flares by the broadband RHESSI spectrometer and called here the Fe line and Fe/Ni line features, are formed mostly of Fe lines but with Ni lines contributing to the similar to 8 keV feature. Possible temperature indicators of these line features are discussed: the peak or centroid energies of the Fe line feature, the line ratio of the Fe line to the Fe/Ni line features, and the equivalent width of the Fe line feature. The equivalent width is by far the most sensitive to temperature. However, results will be confused if, as is commonly believed, the abundance of Fe varies from flare to flare, even during the course of a single flare. With temperature determined from the thermal continuum, the Fe line feature becomes a diagnostic of the Fe abundance in flare plasmas. These results are of interest for other hot plasmas in coronal ionization equilibrium such as stellar flare plasmas, hot gas in galaxies, and older supernova remnants. C1 NASA, Natl Res Council, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Phillips, KJH (reprint author), NASA, Natl Res Council, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. EM phillips@stars.gsfc.nasa.gov NR 62 TC 58 Z9 58 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2004 VL 605 IS 2 BP 921 EP 930 DI 10.1086/382523 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WL UT WOS:000220801900037 ER PT J AU Rots, AH Jahoda, K Lyne, AG AF Rots, AH Jahoda, K Lyne, AG TI Absolute timing of the Crab pulsar with the Rossi X-ray Timing Explorer SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : individual (Crab pulsar); X-rays : stars ID RADIO; EMISSION AB We have monitored the phase of the main X-ray pulse of the Crab pulsar with the Rossi X-Ray Timing Explorer (RXTE) for almost 8 years, since the start of the mission in 1996 January. The absolute time of RXTE's clock is sufficiently accurate to allow this phase to be compared directly with the radio profile. Our monitoring observations of the pulsar took place bi-weekly (during the periods when it was at least 30degrees from the Sun), and we correlated the data with radio timing ephemerides derived from observations made at Jodrell Bank. We have determined the phase of the X-ray main pulse for each observation with a typical error in the individual data points of 50 mus. The total ensemble is consistent with a phase that is constant over the monitoring period, with the X-ray pulse leading the radio pulse by 0.0102 +/- 0.0012 periods in phase, or 344 +/- 40 mus in time. The error estimate is dominated by a systematic error of 40 ms in the radio data, arising from uncertainties in the variable amount of pulse delay due to interstellar scattering and instrumental calibration. The statistical error is 0.00015 periods, or 5 mus. The separation of the main pulse and interpulse appears to be unchanging at timescales of a year or less, with an average value of 0.4001 +/- 0.0002 periods. There is no apparent variation in these values with energy over the 2-30 keV range. The lag between the radio and X-ray pulses may be constant in phase (i.e., rotational in nature) or constant in time (i.e., due to a path-length difference). We are not (yet) able to distinguish between these two interpretations. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Manchester, Dept Phys & Astron, Jodrell Bank, Macclesfield SK11 9DL, Cheshire, England. RP Rots, AH (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS 67, Cambridge, MA 02138 USA. EM arots@head.cfa.harvard.edu RI Jahoda, Keith/D-5616-2012; OI Rots, Arnold/0000-0003-2377-2356 NR 16 TC 50 Z9 50 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2004 VL 605 IS 2 BP L129 EP L132 DI 10.1086/420842 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WM UT WOS:000220802000011 ER PT J AU Watson, D Hjorth, J Levan, A Jakobsson, P O'Brien, PT Osborne, JP Pedersen, K Reeves, JN Tedds, JA Vaughan, SA Ward, MJ Willingale, R AF Watson, D Hjorth, J Levan, A Jakobsson, P O'Brien, PT Osborne, JP Pedersen, K Reeves, JN Tedds, JA Vaughan, SA Ward, MJ Willingale, R TI A very low luminosity X-ray flash: XMM-NEWTON observations of GRB 031203 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; supernovae : general; X-rays : general ID 25 APRIL 1998; OPTICAL AFTERGLOW; UNUSUAL SUPERNOVA; ENERGY RESERVOIR; GRB 990123; ERROR BOX; BURST; EMISSION; BEPPOSAX; GRB-030329 AB GRB 031203 was observed by XMM-Newton twice, first with an observation beginning 6 hr after the burst and again after 3 days. The afterglow had average 0.2-10.0 keV fluxes for the first and second observations of (4.2 +/- 0.1) x 10(-13) and (1.8 +/- 0.1) x 10-(13) ergs cm(-2) s(-1), respectively, decaying very slowly according to a power law with an index of -0.55 +/- 0.05. The prompt soft X-ray flux, inferred from a detection of the dust echo of the prompt emission, strongly implies that this burst is very soft and should be classified as an X-ray flash (XRF) and further, implies a steep temporal slope (less than or similar to - 1.7) between the prompt and afterglow phases or in the early afterglow, very different from the later afterglow decay slope. A power law (Gamma = 1.90 +/- 0.05) with absorption at a level consistent with the Galactic foreground absorption fits the afterglow spectrum well. A bright low- redshift (z = 0.105) galaxy lies within 0".5 of the X-ray position and is likely to be the gamma-ray burst (GRB) host. At this redshift, GRB 031203 is the closest GRB or XRF known after GRB 980425. It has a very low equivalent isotropic gamma-ray energy in the burst (similar to3 x 10(49) ergs) and X-ray luminosity in the afterglow (9 x 10(42) ergs s(-1) at 10 hr), 3-4 orders of magnitude less than typical bursts, though higher than either the faint XRF 020903 or GRB 980425. The rapid initial decline and subsequent very slow fading of the X-ray afterglow is also similar to that observed in GRB 980425, indicating that GRB 031203 may be representative of low-luminosity bursts. C1 Univ Copenhagen, Niels Bohr Inst, Astron Observ, DK-2100 Copenhagen O, Denmark. Univ Leicester, Dept Phys & Astron, Xray Astron Grp, Leicester LE1 7RH, Leics, England. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD USA. RP Watson, D (reprint author), Univ Copenhagen, Niels Bohr Inst, Astron Observ, Juliane Maries Vej 30, DK-2100 Copenhagen O, Denmark. EM darach@astro.ku.dk; jens@astro.ku.dk; anl@star.le.ac.uk; pallja@astro.ku.dk; pto@star.le.ac.uk; julo@star.le.ac.uk; kp@astro.ku.dk; jnr@milkyway.gsfc.nasa.gov; jat@star.le.ac.uk; sav2@star.le.ac.uk; mjw@star.le.ac.uk; rw@star.le.ac.uk RI Hjorth, Jens/M-5787-2014; Watson, Darach/E-4521-2015; Jakobsson, Pall/L-9950-2015; OI Hjorth, Jens/0000-0002-4571-2306; Watson, Darach/0000-0002-4465-8264; Jakobsson, Pall/0000-0002-9404-5650; Tedds, Jonathan/0000-0003-2829-4584 NR 50 TC 65 Z9 66 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2004 VL 605 IS 2 BP L101 EP L104 DI 10.1086/420844 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WM UT WOS:000220802000004 ER PT J AU Leventis, N Rawashdeh, AMM Elder, IA Yang, JH Dass, A Sotiriou-Leventis, C AF Leventis, N Rawashdeh, AMM Elder, IA Yang, JH Dass, A Sotiriou-Leventis, C TI Synthesis and characterization of Ru(II) tris(1,10-phenanthroline)-electron acceptor dyads incorporating the 4-benzoyl-N-methylpyridinium cation or N-benzyl-N '-methyl viologen. Improving the dynamic range, sensitivity, and response time of sol-gel-based optical oxygen sensors SO CHEMISTRY OF MATERIALS LA English DT Article ID FREE-ENERGY RELATIONSHIPS; RUTHENIUM(II) COMPLEXES; ELECTRON-TRANSFER; PHOTOPHYSICAL PROPERTIES; EXCITED-STATE; ARTIFICIAL PHOTOSYNTHESIS; QUENCHING BEHAVIOR; REDOX CHEMISTRY; BUILDING-BLOCKS; PROTON-TRANSFER AB The title compounds were synthesized by Sonogashira coupling reactions of appropriate Ru(II) complexes with the electron acceptors. Characterization was conducted in solution and in frozen matrixes. Finally, the title compounds were evaluated as dopants of sol-gel materials. It was found that the intramolecular quenching efficiency of 4-benzoyl-N-methylpyridinium cation in solution depends on the solvent: photoluminescence is quenched completely in CH3CN, but not in methanol or ethanol. On the other hand, intramolecular emission quenching by 4-benzyl-N-methyl viologen is complete in all solvents. The difference between the two quenchers is traced electrochemically to the solvation of the 4-benzoyl-N-methylpyridiniums by alcohol. In frozen matrixes or adsorbed on the surfaces of silica aerogel, both Ru(II) complex/electron acceptor dyads of this study are photoluminescent, and the absence of quenching has been traced to the environmental rigidity. When doped aerogels are cooled at 77 K, the emission intensity increases by similar to4x, and the spectra shift to the blue, analogous to what is observed with Ru(II) complexes in solutions undergoing fluid-to-rigid transition. However, in contrast to frozen solutions, the luminescent moieties in the bulk of aerogels kept at low temperatures are still accessible to gas-phase quenchers diffusing through the mesopores, leading to more sensitive platforms for sensors than other room-temperature configurations. Thus, the photoluminescence of our Ru(II) complex dyads adsorbed on aerogel is quenchable by O-2 both at room temperature and at 77 K. Furthermore, it was also found that O-2 modulates the photoluminescence of aerogels doped with 4-benzoyl-N-methylpyridinium -based dyads over a wider dynamic range compared with aerogels doped with either our viologen-based dyads or with Ru(II) tris(1,10-phenanthroline) itself. C1 NASA, Glenn Res Ctr, Div Mat, Polymers Branch, Cleveland, OH 44135 USA. Univ Missouri, Dept Chem, Rolla, MO 65409 USA. RP Leventis, N (reprint author), NASA, Glenn Res Ctr, Div Mat, Polymers Branch, 21000 Brookpk Rd,MS 49-1, Cleveland, OH 44135 USA. EM Nicholas.Leventis@gre.nasa.gov; cslevent@umr.edu RI Dass, Amal/A-2520-2011; Dass, Amala/H-4729-2012 OI Dass, Amala/0000-0001-6942-5451 NR 62 TC 43 Z9 43 U1 1 U2 30 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD APR 20 PY 2004 VL 16 IS 8 BP 1493 EP 1506 DI 10.1021/cm034999b PG 14 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 812QU UT WOS:000220854800018 ER PT J AU Knudsen, DJ Bock, BJJ Bounds, SR Burchill, JK Clemmons, JH Curtis, JD Eriksson, AI Koepke, ME Pfaff, RF Wallis, DD Whaley, N AF Knudsen, DJ Bock, BJJ Bounds, SR Burchill, JK Clemmons, JH Curtis, JD Eriksson, AI Koepke, ME Pfaff, RF Wallis, DD Whaley, N TI Lower-hybrid cavity density depletions as a result of transverse ion acceleration localized on the gyroradius scale SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE lower-hybrid cavities; density cavities; ion heating; lower-hybrid solitary structures ID SOLITARY STRUCTURES; WAVE COLLAPSE; MAGNETIZED PLASMAS; SOUNDING ROCKET; FREJA SATELLITE; IONOSPHERE; EIGENMODES; FIELD AB [1] We explore a mechanism by which density depletions associated with lower-hybrid cavities and similar structures are a direct consequence of ion trajectories resulting from transverse energization localized on scales comparable to the ion gyroradius. Specifically, a heating region localized to a flux tube having a diameter of the order of a few ambient thermal ion gyroradii will be depleted of ions because of heated-gyroradius-scale excursions of the ions away from the heating region. Cooler ions outside will have smaller average gyroradii and will be unable to compensate for the depletion inside the heating region. The outflux of energized ions from the heated region results in a density enhancement at its periphery. Motivated by space observations, we characterize density perturbations resulting from an idealized, cylindrically symmetric Gaussian temperature enhancement, using Monte Carlo simulations and an orbit-averaged density calculation. Our model generates density depletions of the order of 10% for a two-fold increase in T-i over the background value and 50% for a fifty-fold increase. In addition to density depletions the model predicts density-enhanced shoulders around cavity perimeters and shows how heated ion tails superimposed on cool ionospheric plasmas can be explained by hot, Maxwellian ions originating on nonlocal flux tubes. We present examples of shoulders observed by sounding rockets and by the Freja satellite. Finally, we use sounding rocket measurements to demonstrate that the distribution of cavity widths ( or chord lengths) is relatively narrow ( 16 +/- 10 m), with an average width that remains nearly unchanged even as plasma density varies over five orders of magnitude. This result is consistent with gyroradius being the key scaling parameter, although it does not rule out other scaling predictions that do not depend on plasma density. C1 Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Aerosp Corp, Los Angeles, CA 90009 USA. Swedish Inst Space Phys, SE-75121 Uppsala, Sweden. W Virginia Univ, Dept Phys, Morgantown, WV 26506 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Magnametrics, Ottawa, ON K1H 7A9, Canada. Univ Calgary, Dept Phys & Astron, Calgary, AB T2N 1N4, Canada. RP CNRS, CETP, Velizy Villacoublay, France. EM knudsen@phys.ucalgary.ca; bock@phys.ucalgary.ca; srb@gamma.physics.uiowa.edu; burchill@phys.ucalgary.ca; james.h.clemmons@aero.org; aie@irfu.se; mark.koepke@mail.wvu.edu; robert.f.pfaff@nasa.gov; wallis@sp-agency.ca RI Eriksson, Anders/C-2887-2009; Pfaff, Robert/F-5703-2012 OI Pfaff, Robert/0000-0002-4881-9715 NR 43 TC 14 Z9 14 U1 0 U2 3 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 APR 20 PY 2004 VL 109 IS A4 AR A04212 DI 10.1029/2003JA010089 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 816CH UT WOS:000221087500001 ER PT J AU Guo, SP Wu, F Albin, S Rogowski, RS AF Guo, SP Wu, F Albin, S Rogowski, RS TI Photonic band gap analysis using finite-difference frequency-domain method SO OPTICS EXPRESS LA English DT Article ID MAXWELLS EQUATIONS; CRYSTALS; MEDIA AB A finite-difference frequency-domain (FDFD) method is applied for photonic band gap calculations. The Maxwell's equations under generalized coordinates are solved for both orthogonal and non-orthogonal lattice geometries. Complete and accurate band gap information is obtained by using this FDFD approach. Numerical results for 2D TE/TM modes in square and triangular lattices are in excellent agreements with results from plane wave method (PWM). The accuracy, convergence and computation time of this method are also discussed. (C) 2004 Optical Society of America. C1 Old Dominion Univ, Dept Elect & Comp Engn, Photon Lab, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, Nondestruct Evaluat Sci Branch, Hampton, VA 23681 USA. RP Guo, SP (reprint author), Old Dominion Univ, Dept Elect & Comp Engn, Photon Lab, Norfolk, VA 23529 USA. EM sguo@odu.edu NR 18 TC 42 Z9 46 U1 1 U2 11 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD APR 19 PY 2004 VL 12 IS 8 BP 1741 EP 1746 DI 10.1364/OPEX.12.001741 PG 6 WC Optics SC Optics GA 813LH UT WOS:000220908100029 PM 19475000 ER PT J AU Duncan, BN Bey, I AF Duncan, BN Bey, I TI A modeling study of the export pathways of pollution from Europe: Seasonal and interannual variations (1987-1997) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE export pathways; Europe; pollution ID TROPICAL TROPOSPHERIC OZONE; CARBON-MONOXIDE; NORTH-ATLANTIC; UNITED-STATES; ASIAN EMISSIONS; AIR-POLLUTION; INTERCONTINENTAL TRANSPORT; TRANSATLANTIC TRANSPORT; BACKGROUND OZONE; SURFACE OZONE AB [1] We present a study of the export pathways of pollution from Europe from 1987 to 1997, using a three-dimensional model of chemistry and transport. The dominant export pathways in winter are advection to the (1) middle/high latitudes of the North Atlantic Ocean, (2) Russia and the Russian Arctic, and (3) middle/low latitudes of the North Atlantic Ocean from western Europe and from northern Africa via the Mediterranean Basin. In summer, export occurs by both advection and convection; advective transport occurs predominantly to Russia and the Mediterranean Basin/northern Africa. There are two major regions of convection in summer that loft European pollution into the free troposphere, one centered over Germany and the other over the Ural Mountains in Russia. Another region of lofting, not associated with moist convection, occurs in northwestern Africa by the Western Saharan Low. Summertime ozone in our model is enhanced by European pollution (similar to5 ppbv on average) in the middle troposphere near these three regions of lofting. European pollution causes summertime surface ozone levels in northern Africa and the Near East to exceed regularly the European Council's human health standard. The two dominant causes of interannual variation in European pollution export are variations in transport, especially associated with the North Atlantic Oscillation (NAO), and changes in anthropogenic emissions. The tropospheric burden of carbon monoxide (CO) from European sources varies by as much as +/-20% over both western Europe and the North Atlantic and +/-15% over the Arctic in winter because of interannual variations in transport. When the NAO is in the positive (negative) phase, the CO burden from European sources tends to be lower (higher) over the North Atlantic and higher (lower) over the Arctic. European emissions of CO and nitrogen oxides decrease by 36% and 20% over the study period, respectively, with a nearly linear concomitant decrease in the CO burden associated with European emissions. We find that it is necessary to consider both of these factors when interpreting trends in observed trace gas concentrations over Europe. C1 Ecole Polytech Fed Lausanne, Lab Modelisat Chim Atmospher, CH-1015 Lausanne, Switzerland. RP Univ Maryland Baltimore Cty, NASA, Goddard Space Flight Ctr, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. EM duncan@code916.gsfc.nasa.gov; isabelle.bey@epfl.ch RI Duncan, Bryan/A-5962-2011 NR 88 TC 80 Z9 79 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 17 PY 2004 VL 109 IS D8 AR D08301 DI 10.1029/2003JD004079 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 815YI UT WOS:000221077200002 ER PT J AU Wendisch, M Pilewskie, P Jakel, E Schmidt, S Pommier, J Howard, S Jonsson, HH Guan, H Schroder, M Mayer, B AF Wendisch, M Pilewskie, P Jakel, E Schmidt, S Pommier, J Howard, S Jonsson, HH Guan, H Schroder, M Mayer, B TI Airborne measurements of areal spectral surface albedo over different sea and land surfaces SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE areal spectral surface albedo; spectral radiative transfer; aerosol particles ID SOLAR RADIATIVE-TRANSFER; SCATTERING; ATMOSPHERE; ALGORITHM; IMPACT; SKY AB [1] Airborne measurements of the ratio of spectral upward and downward irradiances (so-called spectral albedo) are used to derive the areal spectral surface albedo in the wavelength range from 330 to 1670 nm. The data were collected over different sea and land surfaces in cloudless atmospheric conditions during three field campaigns. Measurements from the Albedometer (developed at IfT) and the NASA Solar Spectral Flux Radiometer (SSFR) are employed. Spectral radiative transfer calculations show that atmospheric scattering and absorption within the layer beneath the flight level considerably contribute to the airborne albedo measurements reported here, even for low flight altitudes (0.2-0.5 km). To remove this atmospheric masking, a nonlinear extrapolation of the airborne albedo measurements to the ground is performed. The nonlinearity is due to the vertically inhomogeneous distribution of the particle microphysical properties. This fact underlines the importance of aerosol profile measurements for the proper correction of atmospheric masking. Examples of the extrapolated areal spectral surface albedos are discussed in terms of their solar zenith angle dependence, their small-scale, and general variability. Finally, typical areal spectral surface albedos for different sea and land surfaces, as derived from the three measurement campaigns, are supplied in parameterized form for use in radiative transfer applications. C1 Leibniz Inst Tropospharenforsch IfT, D-04318 Leipzig, Germany. NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. Bay Area Environm Res Inst, Sonoma, CA 95476 USA. Ctr Interdisciplinary Remotely Piloted Aircraft S, Marina, CA 93933 USA. Free Univ Berlin, Inst Space Sci, D-1000 Berlin, Germany. Deutsch Zentrum Luft & Raumfahrt DLR, Inst Atmospher Phys, D-82234 Wessling, Germany. RP Wendisch, M (reprint author), Leibniz Inst Tropospharenforsch IfT, Permoserstr 15, D-04318 Leipzig, Germany. EM wendisch@tropos.de; peter.pilewskie-1@nasa.gov; jaekel@tropos.de; schmidt@tropos.de; jpommier@mail.arc.nasa.gov; howard@solat.arc.nasa.gov; hjonsson@nps.navy.mil; guan@clio.arc.nasa.gov; marc.schroeder@wew.fu-berlin.de; bernhard.mayer@dlr.de RI Mayer, Bernhard/B-3397-2011; Wendisch, Manfred/E-4175-2013; SCHMIDT, KONRAD SEBASTIAN/C-1258-2013 OI Mayer, Bernhard/0000-0002-3358-0190; Wendisch, Manfred/0000-0002-4652-5561; SCHMIDT, KONRAD SEBASTIAN/0000-0003-3899-228X NR 28 TC 37 Z9 37 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 APR 17 PY 2004 VL 109 IS D8 AR D08203 DI 10.1029/2003JD004392 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 815YI UT WOS:000221077200005 ER PT J AU Wagner, CT Lu, IY Hoffman, MH Sun, WQ Trent, JD Connor, J AF Wagner, CT Lu, IY Hoffman, MH Sun, WQ Trent, JD Connor, J TI T-complex polypeptide-1 interacts with the erythrocyte cytoskeleton in response to elevated temperatures SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID HEAT-SHOCK PROTEINS; GROUP-II CHAPERONIN; MOLECULAR CHAPERONES; CARBONIC-ANHYDRASE; IN-VIVO; SACCHAROMYCES-CEREVISIAE; EUKARYOTIC CHAPERONIN; MEMBRANE SKELETON; ESCHERICHIA-COLI; YEAST TCP1 AB Chaperonins are double ring complexes composed of highly conserved 60-kDa protein subunits that are divided into two subgroups. Group II chaperonins are found in archaea and the cytoplasm of eukarya and are believed to function like other chaperonins as part of a protein folding system. We report here that human erythrocytes contain the group II chaperonin T-complex polypeptide 1 (TCP-1) and that this complex translocates from the cytoplasm to the cytoskeleton in response to heat treatment in the absence of overt cell damage. Identification as TCP-1 was determined by immunodetection for TCP-1alpha and corroborated by mass spectroscopy peptide sequencing. Direct visualization by immunofluorescence confirmed peripherally localized TCP-1 in response to heat treatment. Temperatures ranging from 37-50degreesC were demonstrated to have distinct kinetic profiles of induced translocation. Heat-induced binding was shown by Triton shell analysis to be specifically associated with the cytoskeletal proteins. Furthermore, the binding was reversible following removal of the stimulatory condition. A stabilizing process is hypothesized based on the known interactions of chaperonins. C1 LifeCell Corp, Branchburg, NJ 08876 USA. NASA, Astrobiol & Technol Branch, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Wagner, CT (reprint author), LifeCell Corp, 1 Millennium Way, Branchburg, NJ 08876 USA. EM cwagner@lifecell.com NR 62 TC 5 Z9 5 U1 0 U2 0 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3996 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD APR 16 PY 2004 VL 279 IS 16 BP 16223 EP 16228 DI 10.1074/jbc.M310730200 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 811BR UT WOS:000220747900065 PM 14729905 ER PT J AU Minnis, P Gambheer, AV Doelling, DR AF Minnis, P Gambheer, AV Doelling, DR TI Azimuthal anisotropy of longwave and infrared window radiances from the Clouds and the Earth's Radiant Energy System on the Tropical Rainfall Measuring Mission and Terra satellites SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE infrared radiation; surface temperature; remote sensing ID TEMPERATURES; CERES AB [1] Shadowing by vegetation, landforms, or clouds can reduce the surface temperature relative to unshadowed portions of the same land area. This shading effect can cause azimuthal variation of the outgoing infrared radiance that is currently not taken into account in remote sensing and Earth radiation budget analyses. In this paper, multiangle longwave (LW) (5-200 mum) and window (WN) (8-12 mum) radiances taken by the Clouds and the Earth's Radiant Energy System (CERES) rotating azimuth plane scanner on the Tropical Rainfall Measuring Mission (TRMM) and Terra satellites are used to determine the azimuthal anisotropy of LW and WN fields over all solar zenith angles and surface types in clear and cloudy conditions. The azimuthal component of the anisotropy is isolated by constructing limb-darkening models for each category of surface type and topography in each solar zenith angle (SZA) bin. The viewing zenith angle dependence of WN and LW radiances in clear scenes depends on the SZA, possibly because of changes in the boundary layer temperature structure during the day. The observed mean radiances, in general, are greater when viewing the sunlit hemisphere (backscattering) than when viewing the shaded (forward scattering) hemisphere. This forward-back contrast increases with increasing terrain roughness and is stronger for surfaces with open vegetation such as shrubs and grass than for contiguous vegetation like forests. The anisotropy is less well defined for barren deserts. Maximum anisotropy occurs for SZAs between 48degrees and 70degrees. This paper provides the first evidence that clouds also induce longwave azimuthal anisotropy. Strong forward-back radiance contrast is evident for partly, mostly, and overcast scenes for SZA < 48 degrees. The contrast disappears for overcast scenes and decreases for partly and mostly cloudy scenes at higher SZAs. The TRMM sampling is limited and causes some biases at particular angle sets but overall provides a reasonable depiction of the anisotropy at all SZAs. Terra yields a more accurate anisotropy characterization but only for SZAs between 48 degrees and 70 degrees. A simple model constructed from the TRMM results for clear scenes reduces clear-sky temperature prediction RMS errors by 38% or more while minimizing the biases associated with azimuthal anisotropy. The model should yield similar or better reductions in the errors associated with retrievals of skin temperature or LW fluxes, especially those from geostationary satellites. In addition, future analyses of combined TRMM, Terra, and Aqua CERES data will likely provide more accurate correction models that could further reduce errors in surface skin temperature and radiative flux for both clear and cloudy scenes. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Analyt Serv & Mat Inc, Hampton, VA 23666 USA. RP Minnis, P (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM p.minnis@larc.nasa.gov; a.v.gambheer@larc.nasa.gov; d.r.doelling@larc.nasa.gov RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 19 TC 13 Z9 13 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 APR 16 PY 2004 VL 109 IS D8 AR D08202 DI 10.1029/2003JD004471 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 815YH UT WOS:000221077100003 ER PT J AU Mitchell, BM Meck, JV AF Mitchell, BM Meck, JV TI Short-duration spaceflight does not prolong QTc intervals in male astronauts SO AMERICAN JOURNAL OF CARDIOLOGY LA English DT Article AB Although ventricular dysrhythmias are not increased during, and QTc intervals are not prolonged after, short-duration (5 to 16 days) spaceflights, QTc intervals have not previously been reported during these shorter flights. Halter monitor recordings, obtained in 11 male astronauts who flew on shuttle missions ranging from 5 to 10 days, showed that QTc intervals did not change significantly 10 days before launch, on 2 separate days of spaceflight, and 2 days after landing. Taken together, these data and our previous report show that QTc interval prolongation occurs sometime between the 9th and 30th days of spaceflight. (C) 2004 by Excerpta Medical, Inc. C1 NASA, Lyndon B Johnson Space Ctr, Space Life Sci Res Labs, Human Adapt & Countermeasures Off, Houston, TX 77058 USA. Univ Space Res Assoc, Houston, TX USA. RP Meck, JV (reprint author), NASA, Lyndon B Johnson Space Ctr, Space Life Sci Res Labs, Human Adapt & Countermeasures Off, Houston, TX 77058 USA. EM jmeck@ems.jsc.nasa.gov NR 8 TC 4 Z9 4 U1 0 U2 1 PU EXCERPTA MEDICA INC PI NEW YORK PA 650 AVENUE OF THE AMERICAS, NEW YORK, NY 10011 USA SN 0002-9149 J9 AM J CARDIOL JI Am. J. Cardiol. PD APR 15 PY 2004 VL 93 IS 8 BP 1051 EP 1052 DI 10.1016/j.amjcard.2003.12.060 PG 2 WC Cardiac & Cardiovascular Systems SC Cardiovascular System & Cardiology GA 812ZH UT WOS:000220876900023 PM 15081456 ER PT J AU Huo, WM Tarnovsky, V Becker, K AF Huo, WM Tarnovsky, V Becker, K TI Electron impact ionization cross-sections of SF3 and SF5 SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE electron ionization; cross-sections; free radicals; plasma processing ID FREE-RADICALS; DISSOCIATIVE IONIZATION; WAVE-FUNCTIONS; BASIS-SETS; MOLECULES; ENERGY; MODEL AB We report experimental and theoretical studies of the total electron impact ionization cross-sections for the radicals SF3 and SF5. It is shown that for radicals with strongly polar fluoride bonds, the shielding of the attractive dipole interaction potential in the bonding region is important in a proper description of the collision process. The siBED model, which has incorporated the shielding factor, was found to provide cross-sections in agreement with recently re-analyzed experimental data for the species CFx, and NFx (x = 1-3), whereas the DM model and the BEB model, on the other hand, showed large discrepancies with experiment. These findings also hold for the two free radicals SF3 and SF5 studied here, providing further evidence on the importance of a proper shielding of the dipole potential. (C) 2004 Elsevier B.V. All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Stevens Inst Technol, Ctr Environm Syst, Hoboken, NJ 07030 USA. Stevens Inst Technol, Dept Phys & Engn Phys, Hoboken, NJ 07030 USA. RP Huo, WM (reprint author), NASA, Ames Res Ctr, Mail Stop T27B-1, Moffett Field, CA 94035 USA. EM whuo@mail.arc.nasa.gov NR 34 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD APR 15 PY 2004 VL 233 IS 1-3 BP 111 EP 116 DI 10.1016/j.ijms.2003.12.011 PG 6 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 819LR UT WOS:000221316900018 ER PT J AU Bauschlicher, CW AF Bauschlicher, CW TI What is the ground state of Ni(O-2)? SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID GAUSSIAN-BASIS SETS; TRANSITION-METAL ATOMS; COUPLED-CLUSTER THEORY; MOLECULAR CALCULATIONS; ELECTRON CORRELATION; WAVE-FUNCTIONS; ROW ATOMS; ENERGIES; APPROXIMATION; AFFINITIES AB The separation between the B-3(1) and (1)A(1) states of Ni(O-2) is computed using density functional theory (DFT), internally contracted multireference configuration interaction with the multireference analogue of the Davidson correction (IC-MRCI+Q), and coupled-cluster with single and double (and perturbative) triple excitations (CCSD(T)) approaches. Although IC-MRCI+Q and DFT both predict a B-3(1) ground state, the CCSD(T) predicts a (1)A(1) ground state. We suggest that the true separation lies between the IC-MRCI+Q and CCSD(T) values, and that the ground state is likely (1)A(1), despite the IC-MRCI+Q result. We also show that Ni(O-2)(-) has a quartet ground state and, therefore, the (1)A(1) state of Ni(O-2) is probably not observed in the anion photoelectron spectra. C1 NASA, Ames Res Ctr, Space Technol Div, Moffett Field, CA 94035 USA. RP Bauschlicher, CW (reprint author), NASA, Ames Res Ctr, Space Technol Div, Moffett Field, CA 94035 USA. EM bauschli@pegasus.are.nasa.gov NR 29 TC 10 Z9 10 U1 0 U2 1 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 APR 15 PY 2004 VL 108 IS 15 BP 2871 EP 2873 DI 10.1021/jp030960i PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 810SP UT WOS:000220724300006 ER PT J AU Miller, CE Francisco, JS AF Miller, CE Francisco, JS TI Proton affinity of peroxyacetic acid SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID QUADRATIC CONFIGURATION-INTERACTION; MOLECULAR-ORBITAL METHODS; GAS-PHASE BASICITIES; MP2 GRADIENT-METHOD; GAUSSIAN-TYPE BASIS; ORGANIC-MOLECULES; NITRATE; ENERGIES; EXTENSIONS AB The proton affinity of peroxyacetic acid has been studied using ab initio methods. The most stable peroxyacetic acid structure forms a nearly planar five-membered ring in which the carbonyl oxygen atom is hydrogen bonded to the acidic hydrogen atom. The rotational constants, dipole moments, and harmonic vibrational frequencies obtained for this structure are in excellent agreement with available experimental data. Calculations on the protonated peroxyacetic acid system identified low energy structures associated with protonation at each of the three chemically distinguishable oxygen atom sites. Protonation at the carbonyl oxygen site leads to the lowest energy protomer with an optimized structure that also contains a five-membered ring formed by intramolecular hydrogen bonding. The relative energies and proton affinities have been determined at the QCISD and QCISD(T) levels of theory. Additional calculations performed with the ab initio model chemistries CBS-4, CBS-Q, CBS-APNO, and G2(MP2) are in good agreement with the QCISD(T)/6-311 + G(2df,2p) proton affinity. The CBS-Q prediction for the proton affinity of peroxyacetic acid, PA(CBS-Q)(0K) = 775.9 kJ mol(-1), differs by only 2.5 kJ mol(-1) from the proton affinity recently calculated for peroxyacetyl nitrate, PA(CBS-Q)(0K) = -773.4 kJ mol(-1), and outside the error limits of the experimental measurement attributed to the proton affinity recently calculated for peroxyacetyl nitrate, -798 +/- 12 kJ mol(-1). C1 Haverford Coll, Dept Chem, Haverford, PA 19041 USA. Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. Purdue Univ, Dept Earth & Atmospher Sci, W Lafayette, IN 47907 USA. RP Miller, CE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 183-501, Pasadena, CA 91109 USA. EM charles.e.miller@jpl.nasa.gov; jfrancis@chem.purdue.edu NR 29 TC 6 Z9 6 U1 0 U2 4 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 APR 15 PY 2004 VL 108 IS 15 BP 2930 EP 2935 DI 10.1021/jp036748w PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 810SP UT WOS:000220724300013 ER PT J AU Moore, JM AF Moore, JM TI Mars - Blueberry fields for ever SO NATURE LA English DT Editorial Material ID CRYSTALLINE HEMATITE; SURFACE C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Moore, JM (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. EM jeff.moore@nasa.gov NR 12 TC 24 Z9 24 U1 0 U2 4 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 15 PY 2004 VL 428 IS 6984 BP 711 EP 712 DI 10.1038/428711a PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 812EW UT WOS:000220823800025 PM 15085119 ER PT J AU Abbott, B Abbott, R Adhikari, R Ageev, A Allen, B Amin, R Anderson, SB Anderson, WG Araya, M Armandula, H Asiri, F Aufmuth, P Aulbert, C Babak, S Balasubramanian, R Ballmer, S Barish, BC Barker, D Barker-Patton, C Barnes, M Barr, B Barton, MA Bayer, K Beausoleil, R Belczynski, K Bennett, R Berukoff, SJ Betzwieser, J Bhawal, B Bilenko, IA Billingsley, G Black, E Blackburn, K Bland-Weaver, B Bochner, B Bogue, L Bork, R Bose, S Brady, PR Braginsky, VB Brau, JE Brown, DA Brozek, S Bullington, A Buonanno, A Burgess, R Busby, D Butler, WE Byer, RL Cadonati, L Cagnoli, G Camp, JB Cantley, CA Cardenas, L Carter, K Casey, MM Castiglione, J Chandler, A Chapsky, J Charlton, P Chatterji, S Chen, Y Chickarmane, V Chin, D Christensen, N Churches, D Colacino, C Coldwell, R Coles, M Cook, D Corbitt, T Coyne, D Creighton, JDE Creighton, TD Crooks, DRM Csatorday, P Cusack, BJ Cutler, C D'Ambrosio, E Danzmann, K Davies, R Daw, E DeBra, D Delker, T DeSalvo, R Dhurandhar, S Diaz, M Ding, H Drever, RWP Dupuis, RJ Ebeling, C Edlund, J Ehrens, P Elliffe, EJ Etzel, T Evans, M Evans, T Fallnich, C Farnham, D Fejer, MM Fine, M Finn, LS Flanagan, E Freise, A Frey, R Fritschel, P Frolov, V Fyffe, M Ganezer, KS Giaime, JA Gillespie, A Goda, K Gonzalez, G Gossler, S Grandclement, P Grant, A Gray, C Gretarsson, AM Grimmett, D Grote, H Grunewald, S Guenther, M Gustafson, E Gustafson, R Hamilton, WO Hammond, M Hanson, J Hardham, C Harry, G Hartunian, A Heefner, J Hefetz, Y Heinzel, G Heng, IS Hennessy, M Hepler, N Heptonstall, A Heurs, M Hewitson, M Hindman, N Hoang, P Hough, J Hrynevych, M Hua, W Ingley, R Ito, M Itoh, Y Ivanov, A Jennrich, O Johnson, WW Johnston, W Jones, L Jungwirth, D Kalogera, V Katsavounidis, E Kawabe, K Kawamura, S Kells, W Kern, J Khan, A Killbourn, S Killow, CJ Kim, C King, C King, P Klimenko, S Kloevekorn, P Koranda, S Kotter, K Kovalik, J Kozak, D Krishnan, B Landry, M Langdale, J Lantz, B Lawrence, R Lazzarini, A Lei, M Leonhardt, V Leonor, I Libbrecht, K Lindquist, P Liu, S Logan, J Lormand, M Lubinski, M Luck, H Lyons, TT Machenschalk, B MacInnis, M Mageswaran, M Mailand, K Majid, W Malec, M Mann, F Marin, A Marka, S Maros, E Mason, J Mason, K Matherny, O Matone, L Mavalvala, N McCarthy, R McClelland, DE McHugh, M McNamara, P Mendell, G Meshkov, S Messenger, C Mitrofanov, VP Mitselmakher, G Mittleman, R Miyakawa, O Miyoki, S Mohanty, S Moreno, G Mossavi, K Mours, B Mueller, G Mukherjee, S Myers, J Nagano, S Nash, T Naundorf, H Nayak, R Newton, G Nocera, F Nutzman, P Olson, T O'Reilly, B Ottaway, DJ Ottewill, A Ouimette, D Overmier, H Owen, BJ Papa, MA Parameswariah, C Parameswariah, V Pedraza, M Penn, S Pitkin, M Plissi, M Pratt, M Quetschke, V Raab, F Radkins, H Rahkola, R Rakhmanov, M Rao, SR Redding, D Regehr, MW Regimbau, T Reilly, KT Reithmaier, K Reitze, DH Richman, S Riesen, R Riles, K Rizzi, A Robertson, DI Robertson, NA Robison, L Roddy, S Rollins, J Romano, JD Romie, J Rong, H Rose, D Rotthoff, E Rowan, S Rudiger, A Russell, P Ryan, K Salzman, I Sanders, GH Sannibale, V Sathyaprakash, B Saulson, PR Savage, R Sazonov, A Schilling, R Schlaufman, K Schmidt, V Schofield, R Schrempel, M Schutz, BF Schwinberg, P Scott, SM Searle, AC Sears, B Seel, S Sengupta, AS Shapiro, CA Shawhan, P Shoemaker, DH Shu, QZ Sibley, A Siemens, X Sievers, L Sigg, D Sintes, AM Skeldon, K Smith, JR Smith, M Smith, MR Sneddon, P Spero, R Stapfer, G Strain, KA Strom, D Stuver, A Summerscales, T Sumner, MC Sutton, PJ Sylvestre, J Takamori, A Tanner, DB Tariq, H Taylor, I Taylor, R Thorne, KS Tibbits, M Tilav, S Tinto, M Tokmakov, KV Torres, C Torrie, C Traeger, S Traylor, G Tyler, W Ugolini, D Vallisneri, M van Putten, M Vass, S Vecchio, A Vorvick, C Vyachanin, SP Wallace, L Walther, H Ward, H Ware, B Watts, K Webber, D Weidner, A Weiland, U Weinstein, A Weiss, R Welling, H Wen, L Wen, S Whelan, JT Whitcomb, SE Whiting, BF Willems, PA Williams, PR Williams, R Willke, B Wilson, A Winjum, BJ Winkler, W Wise, S Wiseman, AG Woan, G Wooley, R Worden, J Yakushin, I Yamamoto, H Yoshida, S Zawischa, I Zhang, L Zotov, N Zucker, M Zweizig, J AF Abbott, B Abbott, R Adhikari, R Ageev, A Allen, B Amin, R Anderson, SB Anderson, WG Araya, M Armandula, H Asiri, F Aufmuth, P Aulbert, C Babak, S Balasubramanian, R Ballmer, S Barish, BC Barker, D Barker-Patton, C Barnes, M Barr, B Barton, MA Bayer, K Beausoleil, R Belczynski, K Bennett, R Berukoff, SJ Betzwieser, J Bhawal, B Bilenko, IA Billingsley, G Black, E Blackburn, K Bland-Weaver, B Bochner, B Bogue, L Bork, R Bose, S Brady, PR Braginsky, VB Brau, JE Brown, DA Brozek, S Bullington, A Buonanno, A Burgess, R Busby, D Butler, WE Byer, RL Cadonati, L Cagnoli, G Camp, JB Cantley, CA Cardenas, L Carter, K Casey, MM Castiglione, J Chandler, A Chapsky, J Charlton, P Chatterji, S Chen, Y Chickarmane, V Chin, D Christensen, N Churches, D Colacino, C Coldwell, R Coles, M Cook, D Corbitt, T Coyne, D Creighton, JDE Creighton, TD Crooks, DRM Csatorday, P Cusack, BJ Cutler, C D'Ambrosio, E Danzmann, K Davies, R Daw, E DeBra, D Delker, T DeSalvo, R Dhurandhar, S Diaz, M Ding, H Drever, RWP Dupuis, RJ Ebeling, C Edlund, J Ehrens, P Elliffe, EJ Etzel, T Evans, M Evans, T Fallnich, C Farnham, D Fejer, MM Fine, M Finn, LS Flanagan, E Freise, A Frey, R Fritschel, P Frolov, V Fyffe, M Ganezer, KS Giaime, JA Gillespie, A Goda, K Gonzalez, G Gossler, S Grandclement, P Grant, A Gray, C Gretarsson, AM Grimmett, D Grote, H Grunewald, S Guenther, M Gustafson, E Gustafson, R Hamilton, WO Hammond, M Hanson, J Hardham, C Harry, G Hartunian, A Heefner, J Hefetz, Y Heinzel, G Heng, IS Hennessy, M Hepler, N Heptonstall, A Heurs, M Hewitson, M Hindman, N Hoang, P Hough, J Hrynevych, M Hua, W Ingley, R Ito, M Itoh, Y Ivanov, A Jennrich, O Johnson, WW Johnston, W Jones, L Jungwirth, D Kalogera, V Katsavounidis, E Kawabe, K Kawamura, S Kells, W Kern, J Khan, A Killbourn, S Killow, CJ Kim, C King, C King, P Klimenko, S Kloevekorn, P Koranda, S Kotter, K Kovalik, J Kozak, D Krishnan, B Landry, M Langdale, J Lantz, B Lawrence, R Lazzarini, A Lei, M Leonhardt, V Leonor, I Libbrecht, K Lindquist, P Liu, S Logan, J Lormand, M Lubinski, M Luck, H Lyons, TT Machenschalk, B MacInnis, M Mageswaran, M Mailand, K Majid, W Malec, M Mann, F Marin, A Marka, S Maros, E Mason, J Mason, K Matherny, O Matone, L Mavalvala, N McCarthy, R McClelland, DE McHugh, M McNamara, P Mendell, G Meshkov, S Messenger, C Mitrofanov, VP Mitselmakher, G Mittleman, R Miyakawa, O Miyoki, S Mohanty, S Moreno, G Mossavi, K Mours, B Mueller, G Mukherjee, S Myers, J Nagano, S Nash, T Naundorf, H Nayak, R Newton, G Nocera, F Nutzman, P Olson, T O'Reilly, B Ottaway, DJ Ottewill, A Ouimette, D Overmier, H Owen, BJ Papa, MA Parameswariah, C Parameswariah, V Pedraza, M Penn, S Pitkin, M Plissi, M Pratt, M Quetschke, V Raab, F Radkins, H Rahkola, R Rakhmanov, M Rao, SR Redding, D Regehr, MW Regimbau, T Reilly, KT Reithmaier, K Reitze, DH Richman, S Riesen, R Riles, K Rizzi, A Robertson, DI Robertson, NA Robison, L Roddy, S Rollins, J Romano, JD Romie, J Rong, H Rose, D Rotthoff, E Rowan, S Rudiger, A Russell, P Ryan, K Salzman, I Sanders, GH Sannibale, V Sathyaprakash, B Saulson, PR Savage, R Sazonov, A Schilling, R Schlaufman, K Schmidt, V Schofield, R Schrempel, M Schutz, BF Schwinberg, P Scott, SM Searle, AC Sears, B Seel, S Sengupta, AS Shapiro, CA Shawhan, P Shoemaker, DH Shu, QZ Sibley, A Siemens, X Sievers, L Sigg, D Sintes, AM Skeldon, K Smith, JR Smith, M Smith, MR Sneddon, P Spero, R Stapfer, G Strain, KA Strom, D Stuver, A Summerscales, T Sumner, MC Sutton, PJ Sylvestre, J Takamori, A Tanner, DB Tariq, H Taylor, I Taylor, R Thorne, KS Tibbits, M Tilav, S Tinto, M Tokmakov, KV Torres, C Torrie, C Traeger, S Traylor, G Tyler, W Ugolini, D Vallisneri, M van Putten, M Vass, S Vecchio, A Vorvick, C Vyachanin, SP Wallace, L Walther, H Ward, H Ware, B Watts, K Webber, D Weidner, A Weiland, U Weinstein, A Weiss, R Welling, H Wen, L Wen, S Whelan, JT Whitcomb, SE Whiting, BF Willems, PA Williams, PR Williams, R Willke, B Wilson, A Winjum, BJ Winkler, W Wise, S Wiseman, AG Woan, G Wooley, R Worden, J Yakushin, I Yamamoto, H Yoshida, S Zawischa, I Zhang, L Zotov, N Zucker, M Zweizig, J CA LIGO Sci Collaboration TI Setting upper limits on the strength of periodic gravitational waves from PSR J1939+2134 using the first science data from the GEO 600 and LIGO detectors SO PHYSICAL REVIEW D LA English DT Article ID ROTATING RELATIVISTIC STARS; ACCRETING NEUTRON-STARS; X-RAY BINARIES; MILLISECOND PULSARS; RADIATION; INTERFEROMETER; INSTABILITY; B1937+21; SEARCH AB Data collected by the GEO 600 and LIGO interferometric gravitational wave detectors during their first observational science run were searched for continuous gravitational waves from the pulsar J1939+2134 at twice its rotation frequency. Two independent analysis methods were used and are demonstrated in this paper: a frequency domain method and a time domain method. Both achieve consistent null results, placing new upper limits on the strength of the pulsar's gravitational wave emission. A model emission mechanism is used to interpret the limits as a constraint on the pulsar's equatorial ellipticity. C1 CALTECH, LIGO, Pasadena, CA 91125 USA. Max Planck Inst Gravitat Phys, Albert Einstein Inst, D-14476 Golm, Germany. Max Planck Inst Gravitat Phys, Albert Einstein Inst, D-30167 Hannover, Germany. Australian Natl Univ, Canberra, ACT 0200, Australia. CALTECH, Pasadena, CA 91125 USA. Calif State Univ Dominguez Hills, Carson, CA 90747 USA. CALTECH, CaRT, Pasadena, CA 91125 USA. Cardiff Univ, Cardiff CF2 3YB, S Glam, Wales. Carleton Coll, Northfield, MN 55057 USA. Cornell Univ, Ithaca, NY 14853 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Hobart & William Smith Coll, Geneva, NY 14456 USA. Interuniv Ctr Astron & Astrophys, Pune 411007, Maharashtra, India. MIT, LIGO, Cambridge, MA 02139 USA. Hanford Observ, LIGO, Richland, WA 99352 USA. Livingston Observ, LIGO, Livingston, LA 70754 USA. Louisiana State Univ, Baton Rouge, LA 70803 USA. Louisiana Tech Univ, Ruston, LA 71272 USA. Loyola Univ, New Orleans, LA 70118 USA. Max Planck Inst Quantum Opt, D-85748 Garching, Germany. Moscow MV Lomonosov State Univ, Moscow 119992, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Astron Observ Japan, Tokyo 1818588, Japan. Northwestern Univ, Evanston, IL 60208 USA. Salish Kootenai Coll, Pablo, MT 59855 USA. SE Louisiana Univ, Hammond, LA 70402 USA. Stanford Univ, Stanford, CA 94305 USA. Syracuse Univ, Syracuse, NY 13244 USA. Penn State Univ, University Pk, PA 16802 USA. Univ Texas, Brownsville, TX 78520 USA. Texas Southmost Coll, Brownsville, TX 78520 USA. Trinity Univ, San Antonio, TX 78212 USA. Leibniz Univ Hannover, D-30167 Hannover, Germany. Univ Illes Balears, E-07071 Palma de Mallorca, Spain. Univ Birmingham, Birmingham B15 2TT, W Midlands, England. Univ Florida, Gainesville, FL 32611 USA. Univ Glasgow, Glasgow G12 8QQ, Lanark, Scotland. Univ Michigan, Ann Arbor, MI 48109 USA. Univ Oregon, Eugene, OR 97403 USA. Univ Rochester, Rochester, NY 14627 USA. Univ Wisconsin, Milwaukee, WI 53201 USA. Washington State Univ, Pullman, WA 99164 USA. RP CALTECH, LIGO, Pasadena, CA 91125 USA. RI Frey, Raymond/E-2830-2016; Pitkin, Matthew/I-3802-2013; Vyatchanin, Sergey/J-2238-2012; Chen, Yanbei/A-2604-2013; Bilenko, Igor/D-5172-2012; Sylvestre, Julien/A-8610-2009; Casey, Morag/C-9703-2010; Raab, Frederick/E-2222-2011; Rowan, Sheila/E-3032-2010; Lueck, Harald/F-7100-2011; Freise, Andreas/F-8892-2011; Kawabe, Keita/G-9840-2011; Ottewill, Adrian/A-1838-2016; Sigg, Daniel/I-4308-2015; van Putten, Maurice/F-5237-2011; Beausoleil, Raymond/C-5076-2009; Allen, Bruce/K-2327-2012; McClelland, David/E-6765-2010; Vecchio, Alberto/F-8310-2015; Strain, Kenneth/D-5236-2011; Ottaway, David/J-5908-2015; Barker, David/A-5671-2013; Mitrofanov, Valery/D-8501-2012; Finn, Lee Samuel/A-3452-2009; Liu, Sheng/K-2815-2013; Schutz, Bernard/B-1504-2010; OI Frey, Raymond/0000-0003-0341-2636; Whelan, John/0000-0001-5710-6576; Stuver, Amber/0000-0003-0324-5735; O'Shaughnessy, Richard/0000-0001-5832-8517; Taylor, Ian/0000-0001-5040-0772; Zweizig, John/0000-0002-1521-3397; Aulbert, Carsten/0000-0002-1481-8319; Pitkin, Matthew/0000-0003-4548-526X; Sylvestre, Julien/0000-0001-8136-4348; Lueck, Harald/0000-0001-9350-4846; Ottewill, Adrian/0000-0003-3293-8450; Sigg, Daniel/0000-0003-4606-6526; Allen, Bruce/0000-0003-4285-6256; McClelland, David/0000-0001-6210-5842; Vecchio, Alberto/0000-0002-6254-1617; Strain, Kenneth/0000-0002-2066-5355; Finn, Lee Samuel/0000-0002-3937-0688; Heurs, Michele/0000-0002-5577-2273; Freise, Andreas/0000-0001-6586-9901; Tokmakov, Kirill/0000-0002-2808-6593; Whiting, Bernard F/0000-0002-8501-8669; Papa, M.Alessandra/0000-0002-1007-5298 NR 46 TC 163 Z9 163 U1 0 U2 9 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD APR 15 PY 2004 VL 69 IS 8 AR 082004 DI 10.1103/PhysRevD.69.082004 PG 16 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 818XI UT WOS:000221277400006 ER PT J AU Tinto, M Estabrook, FB Armstrong, JW AF Tinto, M Estabrook, FB Armstrong, JW TI Time delay interferometry with moving spacecraft arrays SO PHYSICAL REVIEW D LA English DT Article ID LISA AB Space-borne interferometric gravitational wave detectors, sensitive in the low-frequency (millihertz) band, will fly in the next decade. In these detectors the spacecraft-to-spacecraft light-travel-times will necessarily be unequal, time varying, and (due to aberration) have different time delays on up and down links. The reduction of data from moving interferometric laser arrays in solar orbit will in fact encounter nonsymmetric up- and down-link light time differences that are about 100 times larger than has previously been recognized. The time-delay interferometry (TDI) technique uses knowledge of these delays to cancel the otherwise dominant laser phase noise and yields a variety of data combinations sensitive to gravitational waves. Under the assumption that the (different) up- and down-link time delays are constant, we derive the TDI expressions for those combinations that rely only on four interspacecraft phase measurements. We then turn to the general problem that encompasses time dependence of the light-travel times along the laser links. By introducing a set of noncommuting time-delay operators, we show that there exists a quite general procedure for deriving generalized TDI combinations that account for the effects of time dependence of the arms. By applying our approach we are able to re-derive the "flex-free" expression for the unequal-arm Michelson combinations X-1, and obtain the generalized expressions for the TDI combinations called relay, beacon, monitor, and symmetric Sagnac. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Space Radiat Lab, Pasadena, CA 91109 USA. RP Tinto, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Massimo.Tinto@jpl.nasa.gov; Frank.B.Estabrook@jpl.nasa.gov; John.W.Armstrong@jpl.nasa.gov NR 17 TC 51 Z9 53 U1 0 U2 2 PU AMER 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 APR 15 PY 2004 VL 69 IS 8 AR 082001 DI 10.1103/PhysRevD.69.082001 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 818XI UT WOS:000221277400003 ER PT J AU Cota, GF Wang, H Comiso, JC AF Cota, GF Wang, H Comiso, JC TI Transformation of global satellite chlorophyll retrievals with a regionally tuned algorithm SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE algorithm; global satellite; chlorophyll ID SEAWIFS AB "Global" algorithms for satellite remote sensing do not always provide accurate retrievals in all areas of the ocean, particularly in coastal areas and high latitudes. Our current arctic algorithm shows that low chlorophyll concentrations ( similar to 0.6 mg m(-3)) are overestimated by the OC4V4 algorithm for Sea-viewing Wide Field-of-view Sensor (SeaWiFS), while higher concentrations common in blooms are underestimated almost twofold. Alternative algorithms or regionally tuned relationships can be used to produce more reliable chlorophyll retrievals; however, reprocessing of huge satellite data sets can be untenable. Several approaches were investigated to convert global products into regional values to improve accuracy while minimizing errors across the range of values. A simple, rapid transformation scheme employing linear interpolation circumvents reprocessing of entire data sets, but yields much more accurate regional values for the Arctic. (C) 2004 Elsevier Inc. All rights reserved. C1 Old Dominion Univ, Ctr Coastal Phys Oceanog, Norfolk, VA 23508 USA. NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. RP Cota, GF (reprint author), Old Dominion Univ, Ctr Coastal Phys Oceanog, 768 W 52nd St, Norfolk, VA 23508 USA. EM gcota@odu.edu NR 9 TC 33 Z9 33 U1 0 U2 5 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 APR 15 PY 2004 VL 90 IS 3 BP 373 EP 377 DI 10.1016/j.rse.2004.01.005 PG 5 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 819IO UT WOS:000221308800008 ER PT J AU Bhattacharya, P Bellon, P Averback, RS Hales, SJ AF Bhattacharya, P Bellon, P Averback, RS Hales, SJ TI Nanocrystalline TiAl powders synthesized by high-energy ball milling: effects of milling parameters on yield and contamination SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE intermetallics; nanostructures; mechanical alloying ID PROCESS-CONTROL AGENTS; THERMAL-STABILITY; CRYSTALLITE SIZE; AL POWDERS; ALLOYS AB High-energy ball milling was employed to produce nanocrystalline Ti-Al powders. As sticking of the powders can be sufficiently severe to result in a near zero yield, emphasis was placed on varying milling conditions so as to increase the yield, while avoiding contamination of the powders. The effects of milling parameters such as milling tools, initial state of the powders and addition of process control agents (PCA's) were investigated. Cyclohexane, stearic acid and titanium hydride were used as PCA's. Milling was conducted either in a Cr-steel vial with C-steel balls. or in a tungsten carbide (WC) vial with WC balls, using either elemental or pre-alloyed powders. Powder samples were characterized using X-ray diffraction, scanning and transmission electron microscopy. In the absence of PCA's mechanical alloying in a WC vial and attrition milling in a Cr-steel vial were shown to lead to satisfactory yields, about 65-80%, without inducing any significant contamination of the powders. The results suggest that sticking of the powders on to the milling tools is correlated with the phase evolution occurring in these powders during milling. (C) 2003 Elsevier B.V. All rights reserved. C1 Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA. Univ Illinois, Frederick Seitz Mat Res Lab, Urbana, IL 61801 USA. NASA, Langley Res Ctr, MS188A, Hampton, VA 23681 USA. RP Bellon, P (reprint author), Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA. EM bellon@uiuc.edu NR 25 TC 49 Z9 50 U1 1 U2 20 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD APR 14 PY 2004 VL 368 IS 1-2 BP 187 EP 196 DI 10.1016/j.jallcom.2003.08.079 PG 10 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 809JO UT WOS:000220633200031 ER PT J AU Giglio, L Kendall, JD AF Giglio, L Kendall, JD TI Commentary on "Improving the seasonal cycle and interannual variations of biomass burning aerosol sources" by Generoso et al. SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Editorial Material ID INFRARED DATA; TRMM VIRS AB In a recent published paper, Generoso et al. (2003) describe a method for improving the spatial and temporal distribution of pyrogenic aerosol emission inventories. In the course of their analysis, the authors note several significant discrepancies in the seasonality of burning as observed by the Visible and Infrared Scanner (VIRS) and four other biomass burning data sets derived from satellite observations. In this commentary we explain the source of these discrepancies and clarify the origin of the VIRS observations that were used by Generoso et al. C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. RP Giglio, L (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Code 923, Greenbelt, MD 20771 USA. EM giglio@hades.gsfc.nasa.gov NR 8 TC 5 Z9 5 U1 0 U2 1 PU EUROPEAN GEOPHYSICAL SOC PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD APR 13 PY 2004 VL 4 BP 585 EP 587 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 812MR UT WOS:000220844100001 ER PT J AU Herrmann, AD Patzkowsky, ME Pollard, D AF Herrmann, AD Patzkowsky, ME Pollard, D TI The impact of paleogeography, PCO2, poleward ocean heat transport and sea level change on global cooling during the Late Ordovician SO PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY LA English DT Article DE Late Ordovician; glaciation; atmospheric general circulation model; atmospheric pCO(2) ID CLIMATE MODEL GENESIS; TRANSFER SCHEME LSX; ATMOSPHERIC CO2; PHANEROZOIC TIME; NORTH-AMERICA; REVISED MODEL; LATE MIDDLE; GLACIATION; CANADA; OCEANOGRAPHY AB We performed sensitivity experiments with the global climate model GENESIS on two stages of the Upper Ordovician (Caradocian, similar to 454 Ma; Ashgillian, similar to 446 Ma) under a range of atmospheric pCO(2) values (8-18 X PAL; Pre-industrial Atmospheric Level), high and low sea level, and two values of poleward ocean heat transport in order to determine the importance of these variables on global cooling. We then coupled a three-dimensional ice sheet model to the global climate model in order to investigate the necessary boundary conditions for ice sheet formation. All simulations with a high sea level and normal heat transport remain free of ice sheets, even with PCO2 levels as low as 8 x PAL. In the Caradocian simulations, ice sheets form in three scenarios: (1) with PCO2 Of 8 X PAL and a low sea level and normal poleward ocean heat transport, (2) with pCO(2) of 8 x PAL and a high sea level and reduced (50% of normal) poleward ocean heat transport, and (3) with PCO2 of 15 x PAL and a low sea level and reduced poleward ocean heat transport. In the Ashgillian simulations, ice sheets form in only two scenarios: (1) with pCO(2) of 8 x PAL and a low sea level and normal poleward ocean heat transport, or (2) with pCO(2) of 8 x PAL and a high sea level and reduced poleward ocean heat transport. The ice sheets in the Ashgillian experiments are larger and thicker than the ice sheets in the Caradocian simulations because the southward movement of Gondwana increased land area in the higher southern latitudes where ice sheets could grow. The threshold for glaciation under Ashgillian paleogeography is 8 x PAL and either a low sea level (exposed shelves) or a reduced poleward ocean heat transport. While the paleogeographic evolution and a drop in pCO(2) during the Late Ordovician cooled the global climate, changes in additional factors were required to initiate ice sheet formation, such as a drop in sea level, a reduction in poleward ocean heat transport, or a combination of both. (C) 2004 Elsevier B.V. All rights reserved. C1 Penn State Univ, NASA, Astrobiol Inst, University Pk, PA 16802 USA. Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. Penn State Univ, EMS Environm Inst, University Pk, PA 16802 USA. RP George Washington Univ, Dept Earth & Environm Sci, Bell Hall B01C1, Washington, DC 20052 USA. EM achim@gwu.edu RI Herrmann, Achim/A-8441-2013 NR 62 TC 35 Z9 37 U1 0 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-0182 EI 1872-616X J9 PALAEOGEOGR PALAEOCL JI Paleogeogr. Paleoclimatol. Paleoecol. PD APR 13 PY 2004 VL 206 IS 1-2 BP 59 EP 74 DI 10.1016/j.palaeo.2003.12.019 PG 16 WC Geography, Physical; Geosciences, Multidisciplinary; Paleontology SC Physical Geography; Geology; Paleontology GA 811IB UT WOS:000220764500004 ER PT J AU Ng, HT Matthews, K Chen, YP Nguyen, P Li, J Han, J Meyyappan, M AF Ng, HT Matthews, K Chen, YP Nguyen, P Li, J Han, J Meyyappan, M TI Three-dimensional columnar optical nanostructures fabricated by using lithography-free templating approach SO APPLIED PHYSICS LETTERS LA English DT Article ID INTERCONNECTS; RESOLUTION; NANOWIRES; NANOTUBES AB Using a nanowire-based templating approach, lithography-free fabrication of three-dimensional circular optical nanostructures with a minimum physical size of 20 nm is demonstrated. Regular circular gratings with alternating transparent and opaque annular zones and having discrete nanometer length scale separations can be easily achieved. These columnar optical nanostructures could potentially be used for direct integration with other optical components. (C) 2004 American Institute of Physics. C1 NASA, Ctr Nanotechnol, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Ng, HT (reprint author), NASA, Ctr Nanotechnol, Ames Res Ctr, Moffett Field, CA 94035 USA. EM hng@mail.arc.nasa.gov RI Li, Jun/H-7771-2013 OI Li, Jun/0000-0002-3689-8946 NR 21 TC 3 Z9 3 U1 0 U2 12 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 12 PY 2004 VL 84 IS 15 BP 2898 EP 2900 DI 10.1063/1.1704858 PG 3 WC Physics, Applied SC Physics GA 810UB UT WOS:000220728100060 ER PT J AU Ziad, A Schock, M Chanan, GA Troy, M Dekany, R Lane, BF Borgnino, J Martin, F AF Ziad, A Schock, M Chanan, GA Troy, M Dekany, R Lane, BF Borgnino, J Martin, F TI Comparison of measurements of the outer scale of turbulence by three different techniques SO APPLIED OPTICS LA English DT Article ID PALOMAR TESTBED INTERFEROMETER; ADAPTIVE OPTICS; ATMOSPHERIC-TURBULENCE; PERFORMANCE; MONITOR AB We have made simultaneous and nearly simultaneous measurements of L-0, the outer scale of turbulence, at the Palomar Observatory by using three techniques: angle-of-arrival covariance measurements with the Generalized Seeing Monitor (GSM), differential-image-motion measurements with the adaptive-optics system on the Hale 5-m telescope, and fringe speed measurements with the Palomar Testbed Interferometer (PTI). The three techniques give consistent results, an outer scale of approximately 10-20 m, despite the fact that the spatial scales of the three instruments vary from 1 m for the GSM to 100 m for the PTI. (C) 2004 Optical Society of America. C1 Univ Nice, UMR Astrophys 6525, F-06108 Nice 2, France. CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA. RP Ziad, A (reprint author), Univ Nice, UMR Astrophys 6525, F-06108 Nice 2, France. EM aziz.ZIAD@unice.fr NR 32 TC 35 Z9 35 U1 1 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 APR 10 PY 2004 VL 43 IS 11 BP 2316 EP 2324 DI 10.1364/AO.43.002316 PG 9 WC Optics SC Optics GA 811GF UT WOS:000220759700015 PM 15098834 ER PT J AU Eriksen, HK Hansen, FK Banday, AJ Gorski, KM Lilje, PB AF Eriksen, HK Hansen, FK Banday, AJ Gorski, KM Lilje, PB TI Asymmetries in the cosmic microwave background anisotropy field SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; methods : statistical ID PROBE WMAP OBSERVATIONS; POWER SPECTRUM; MAPS AB We report on the results from two independent but complementary statistical analyses of the Wilkinson Microwave Anisotropy Probe (WMAP) first-year data, based on the power spectrum and N-point correlation functions. We focus on large and intermediate scales ( larger than about 3degrees) and compare the observed data against Monte Carlo ensembles with WMAP-like properties. In both analyses, we measure the amplitudes of the large-scale fluctuations on opposing hemispheres and study the ratio of the two amplitudes. The power-spectrum analysis shows that this ratio for WMAP, as measured along the axis of maximum asymmetry, is high at the 95%-99% level ( depending on the particular multipole range included). The axis of maximum asymmetry of the WMAP data is weakly dependent on the multipole range under consideration but tends to lie close to the ecliptic axis. In the N-point correlation-function analysis, we focus on the northern and southern hemispheres defined in ecliptic coordinates, and we find that the ratio of the large-scale fluctuation amplitudes is high at the 98% - 99% level. Furthermore, the results are stable with respect to choice of Galactic cut and also with respect to frequency band. A similar asymmetry is found in the COBE Differential Microwave Radiometer (DMR) map, and the axis of maximum asymmetry is close to the one found in the WMAP data. C1 Univ Oslo, Inst Theoret Astrophys, N-0315 Oslo, Norway. Univ Roma Tor Vergata, Dipartimento Fis, I-00133 Rome, Italy. Max Planck Inst Astrophys, D-85741 Garching, Germany. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Oslo, Ctr Math Applicat, N-0316 Oslo, Norway. Univ Warsaw Observ, PL-00478 Warsaw, Poland. RP Eriksen, HK (reprint author), Univ Oslo, Inst Theoret Astrophys, POB 1029 Blindern, N-0315 Oslo, Norway. EM h.k.k.eriksen@astro.uio.no; frode.hansen@roma2.infn.it; banday@mpa-garching.mpg.de; krzysztof.m.gorski@jpl.nasa.gov; per.lilje@astro.uio.no RI Lilje, Per/A-2699-2012; OI Lilje, Per/0000-0003-4324-7794 NR 22 TC 431 Z9 432 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2004 VL 605 IS 1 BP 14 EP 20 DI 10.1086/382267 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WJ UT WOS:000220801700003 ER PT J AU Rhodes, J Refregier, A Collins, NR Gardner, JP Groth, EJ Hill, RS AF Rhodes, J Refregier, A Collins, NR Gardner, JP Groth, EJ Hill, RS TI Measurement of cosmic shear with the space telescope imaging spectrograph SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; dark matter; gravitational lensing ID WEAK LENSING MEASUREMENTS; EMISSION-LINE GALAXIES; LARGE-SCALE STRUCTURE; STIS PARALLEL SURVEY; POWER SPECTRUM; PHOTOMETRY; SHAPELETS; FIELD AB Weak lensing by large-scale structure allows a direct measure of the dark matter distribution. We have used parallel images taken with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope to measure weak lensing, or cosmic shear. We measure the shapes of 26,036 galaxies in 1292 STIS fields and measure the shear variance at a scale of 0.'51. The charge transfer efficiency (CTE) of STIS has degraded over time and introduces a spurious ellipticity into galaxy shapes during the readout process. We correct for this effect as a function of signal-to-noise ratio and CCD position. We further show that the detected cosmic shear signal is nearly constant in time over the approximately 4 yr of observation. We detect cosmic shear at the 5.1 sigma level, and our measurement of the shear variance is consistent with theoretical predictions in a LambdaCDM universe. This provides a measure of the normalization of the mass power spectrum sigma(8) = (1.02 +/- 0.16)(0.3/Omega(m)) (0.46)(0.21/Gamma)(0.18). The 1 sigma error includes noise, cosmic variance, systematics, and the redshift uncertainty of the source galaxies. This is consistent with previous cosmic shear measurements, but tends to favor those with a high value of sigma(8). It is also consistent with the recent determination of sigma(8) from the Wilkinson Microwave Anisotropy Probe (WMAP) experiment. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. CALTECH, Pasadena, CA 91125 USA. CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. Inst Astron, Cambridge CB3 OHA, England. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Sci Syst & Applicat Inc, Greenbelt, MD USA. RP Rhodes, J (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. EM rhodes@astro.caltech.edu NR 35 TC 45 Z9 45 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2004 VL 605 IS 1 BP 29 EP 36 DI 10.1086/382181 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WJ UT WOS:000220801700005 ER PT J AU Gorjian, V Werner, MW Jarrett, TH Cole, DM Ressler, ME AF Gorjian, V Werner, MW Jarrett, TH Cole, DM Ressler, ME TI 10 micron imaging of Seyfert galaxies from the 12 micron sample SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : nuclei; galaxies : Seyfert; infrared : galaxies ID ACTIVE GALACTIC NUCLEI; INFRARED OBSERVATIONS; BRIGHT GALAXIES; UNIFIED MODEL; NGC 4051; EMISSION; VARIABILITY; PHOTOMETRY; CONTINUUM; NGC-1068 AB We present small-aperture (1."5) photometry and new high-resolution images at 10 mum (N band) for 87 Seyfert galaxies from the Extended 12 mum Sample drawn from the IRAS database. With this data we hope to test the predictions of the unified model for active galactic nuclei and to search for bright, extended circumnuclear 10 mum emission. We detected 62 Seyfert galaxies, 18 of which have no previously published small-aperture photometry. All the detected sources, both Seyfert 1's and Seyfert 2's, show a central point source. The 31 Seyfert 1's and 31 Seyfert 2's that we detected have similar luminosity distributions. Except for previously known bright extended 10 mum structure around Arp 220, NGC 1068, and NGC 7469, we see definitive evidence for bright extended emission around only one new object: Mrk 1239. Four other Seyfert 1' s and six other Seyfert 2' s show evidence of faint, low-level extended emission. One Seyfert 1 and two Seyfert 2' s show evidence of significantly increased flux over previously published small-aperture values. We also compared the N-band data with the J - K-s color that we derived from the Two Micron All Sky Survey (2MASS). There is a distinct trend of redder central bulge J - K-s colors corresponding to brighter absolute N-band magnitudes. In color-magnitude space there is a definite grouping of Seyfert 1' s and Seyfert 2' s, with two sets of outliers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Jet Prop Lab, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. RP Gorjian, V (reprint author), CALTECH, Jet Prop Lab, MS 169-327,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM varoujan.gorjian@jpl.nasa.gov; michael.w.werner@jpl.nasa.gov; jarrett@ipac.caltech.edu; david.m.cole@jpl.nasa.gov; michael.e.ressler@jpl.nasa.gov NR 45 TC 36 Z9 36 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2004 VL 605 IS 1 BP 156 EP 167 DI 10.1086/381791 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WJ UT WOS:000220801700014 ER PT J AU Plume, R Kaufman, MJ Neufeld, DA Snell, RL Hollenbach, DJ Goldsmith, PF Howe, J Bergin, EA Melnick, GJ Bensch, F AF Plume, R Kaufman, MJ Neufeld, DA Snell, RL Hollenbach, DJ Goldsmith, PF Howe, J Bergin, EA Melnick, GJ Bensch, F TI Water absorption from line-of-sight clouds toward W49A SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; ISM : abundances; ISM : clouds; ISM : individual (W49); ISM : molecules; stars : formation ID WAVE-ASTRONOMY-SATELLITE; H-II-REGIONS; LATITUDE TRANSLUCENT CLOUD; SPIRAL-ARM CLOUDS; DISSOCIATIVE RECOMBINATION; MOLECULAR CLOUD; BRANCHING RATIOS; H2O; EMISSION; ORION AB We have observed six clouds along the line of sight toward W49A using the Submillimeter Wave Astronomy Satellite and several ground-based observatories. The ortho-H2O 1(10) --> 1(01) and OH (1665 and 1667 MHz) transitions are observed in absorption, whereas the low-J CO, (CO)-C-13, and (CO)-O-18 lines, as well as the [C I] P-3(1)-P-3(0) transition, are seen in emission. The emission lines allow us to determine the gas density (n similar to 1500 - 3000 cm(-3)) and CO column densities [N(CO) similar to 7.9 x 10(15)-2.8 x 10(17) cm(-2)] using a standard large velocity gradient analysis. By using both the o-H-2 O-18 and o-H2O absorption lines, we are able to constrain the column-averaged o-H2O abundances in each line-of-sight cloud to within about an order of magnitude. Assuming the standard N(H-2)/N(CO) ratio of 10(4), we find N(o-H2O)/N(H-2) = 8.1 x 10(-8) to 4 x 10(-7) for three clouds with optically thin water lines. In three additional clouds, the H2O lines are saturated, so we have used observations of the (H2O)-O-18 ground-state transition to find upper limits to the water abundance of 8.2 x 10(-8) to 1.5 x 10(-6). We measure the OH abundance from the average of the 1665 and 1667 MHz observations and find N(OH)/N(H-2) = 2.3 x 10(-7) to 1.1 x 10(-6). The o-H2O and OH abundances are similar to those determined for line-of-sight water absorption features toward W51 and Sgr B2 but are higher than those seen from water emission lines in molecular clouds. However, the clouds toward W49 have lower ratios of OH relative to H2O column densities than are predicted by simple models, which assume that dissociative recombination is the primary formation pathway for OH and H2O. Building on the 2002 work of Neufeld and coworkers, we present photochemistry models including additional chemical effects, which can also explain the observed OH and H2O column densities, as well as the observed H2O/CO abundance ratios. C1 Univ Calgary, Dept Phys & Astron, Calgary, AB T2N 1N4, Canada. San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Cornell Univ, Dept Astron, Natl Astron & Ionosphere Ctr, Ithaca, NY 14853 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Plume, R (reprint author), Univ Calgary, Dept Phys & Astron, 2500 Univ Dr NW, Calgary, AB T2N 1N4, Canada. RI Goldsmith, Paul/H-3159-2016 NR 35 TC 35 Z9 35 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2004 VL 605 IS 1 BP 247 EP 258 DI 10.1086/382204 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WJ UT WOS:000220801700021 ER PT J AU Pravdo, SH Tsuboi, Y Maeda, Y AF Pravdo, SH Tsuboi, Y Maeda, Y TI X-rays from HH 80, HH 81, and the central region SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : Herbig-Haro objects; ISM : individual (HH 80, HH 81); X-rays : ISM ID HERBIG-HARO OBJECTS; THERMAL RADIO JET; ORION NEBULA; PROPER MOTIONS; GGD 27-IRS; HH 80-81; T-TAURI; EMISSION; REFLECTION; STARS AB We report detections of X-rays from HH 80 and HH 81 with the ACIS instrument on the Chandra X-Ray Observatory. These are among the most luminous Herbig-Haro ( HH) sources in the optical, and they are now the most luminous known in X-rays. These X-rays arise from the strong shocks that occur when the southern extension of this bipolar outflow slams into the ambient material. There is a one-to-one correspondence between regions of high X-ray emission and high Halpha emission. The X-ray luminosities of HH 80 and HH 81 are 4.5 and 4.3 x 10(31) ergs s(-1), respectively, assuming that the measured low-energy absorption is not in the sources. The measured temperature of the HH plasma is not as large as that expected from the maximum velocities seen in the extended tails of the optical emission lines. Rather, it is consistent with the similar to 10(6) K temperature of the "narrow'' core of the optical lines. There is no observed emission from HH 80 North, the northern extension of the bipolar flow, based on a measurement of lower sensitivity. We imaged the central region of the bipolar flow revealing a complex of X-ray sources, including one near but not coincident with the putative power source in the radio and infrared. This source, CXOPTM J181912.4 - 204733, has no counterparts at other wavelengths and is consistent in luminosity and spectrum with a massive star with A(V) similar to 90 mag. It may contribute significantly to the power input to the complex. Alternatively, this emission might be extended X-rays from outflows close to the power source. We detect 94 X-ray sources overall in this area of star formation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Chuo Univ, Fac Sci & Engn, Dept Phys, Bunkyo Ku, Tokyo 1128551, Japan. Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Dept High Energy Astrophys, Kanagawa 2298510, Japan. RP Pravdo, SH (reprint author), CALTECH, Jet Prop Lab, 306-431,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM spravdo@jpl.nasa.gov; tsuboi@phys.chuo-u.ac.jp; ymaeda@astro.isas.jaxa.jp NR 42 TC 30 Z9 30 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2004 VL 605 IS 1 BP 259 EP 271 DI 10.1086/382220 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WJ UT WOS:000220801700022 ER PT J AU Sano, T Inutsuka, S Turner, NJ Stone, JM AF Sano, T Inutsuka, S Turner, NJ Stone, JM TI Angular momentum transport by magnetohydrodynamic turbulence in accretion disks: Gas pressure dependence of the saturation level of the magnetorotational instability SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; diffusion; instabilities; MHD; turbulence ID LOCAL AXISYMMETRICAL SIMULATIONS; WEAKLY MAGNETIZED DISKS; 3-DIMENSIONAL SIMULATIONS; NONLINEAR EVOLUTION; OHMIC DISSIPATION; BLACK-HOLES; SHEAR-FLOW; HALL TERM; RECONNECTION; MECHANISM AB The saturation level of the magnetorotational instability (MRI) is investigated using three-dimensional MHD simulations. The shearing box approximation is adopted and the vertical component of gravity is ignored, so that the evolution of the MRI is followed in a small local part of the disk. We focus on the dependence of the saturation level of the stress on the gas pressure, which is a key assumption in the standard alpha disk model. From our numerical experiments we find that there is a weak power-law relation between the saturation level of the Maxwell stress and the gas pressure in the nonlinear regime; the higher the gas pressure, the larger the stress. Although the power-law index depends slightly on the initial field geometry, the relationship between stress and gas pressure is independent of the initial field strength and is unaffected by ohmic dissipation if the magnetic Reynolds number is at least 10. The relationship is the same in adiabatic calculations, where pressure increases over time, and nearly isothermal calculations, where pressure varies little with time. Over the entire region of parameter space explored, turbulence driven by the MRI has many characteristic ratios such as that of the Maxwell stress to the magnetic pressure. We also find that the amplitudes of the spatial fluctuations in density and the time variability in the stress are characterized by the ratio of magnetic pressure to gas pressure in the nonlinear regime. Our numerical results are qualitatively consistent with an idea that the saturation level of the MRI is determined by a balance between the growth of the MRI and the dissipation of the field through reconnection. The quantitative interpretation of the pressure-stress relation, however, may require advances in the theoretical understanding of nonsteady magnetic reconnection. C1 Univ Cambridge, Ctr Math Sci, Dept Appl Math & Theoret Phys, Cambridge CB3 0WA, England. Osaka Univ, Inst Laser Engn, Suita, Osaka 5650871, Japan. Kyoto Univ, Dept Phys, Kyoto 6068502, Japan. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. RP Univ Cambridge, Ctr Math Sci, Dept Appl Math & Theoret Phys, Wilberforce Rd, Cambridge CB3 0WA, England. EM sano@ile.osaka-u.ac.jp RI Sano, Takayoshi/E-7860-2010; OI Turner, Neal/0000-0001-8292-1943 NR 40 TC 159 Z9 159 U1 1 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 APR 10 PY 2004 VL 605 IS 1 BP 321 EP 339 DI 10.1086/382184 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WJ UT WOS:000220801700028 ER PT J AU Meier, DL AF Meier, DL TI Ohm's law in the fast lane: General relativistic charge dynamics SO ASTROPHYSICAL JOURNAL LA English DT Article DE black hole physics; gamma rays : bursts; MHD; relativity ID EXTRAGALACTIC JETS; BLACK-HOLE; SIMULATIONS; PLASMA AB Fully relativistic and causal equations for the flow of charge in curved spacetime are derived. It is believed that this is the first set of equations to be published that correctly describes the flow of charge, as well as the evolution of the electromagnetic field, in highly dynamical relativistic environments on timescales much shorter than the collapse time (GM / c(3)). The equations will therefore be important for correctly investigating problems such as the dynamical collapse of magnetized stellar cores to black holes and the production of jets. Both are potentially important problems in the study of gamma-ray burst engine models and in predicting the dynamical morphology of the collapse and the character of the gravitational waves generated. This system of equations, given the name of "charge dynamics,'' is analogous to those of hydrodynamics (which describe the flow of mass in spacetime rather than the flow of charge). The most important equation in the system is the relativistic generalized Ohm's law, which is used to compute time-dependent four-current. Unlike other equations for the current now in use, this one ensures that charge drift velocities remain less than the speed of light, takes into account the finite current rise time, is expressed in a covariant form, and is suitable for general relativistic computations in an arbitrary metric. It includes the standard known effects (Lorentz force, Hall effect, pressure effect, and resistivity) and reduces to known forms of Ohm's law in the appropriate limits. In addition, the plasma particles are allowed to have highly relativistic drift velocities, resulting in an implicit equation for the "current beaming factor'' gamma(q). It is proposed that, short of solving the multifluid plasma equations or the relativistic Boltzmann equation itself, these are the most general expressions for relativistic current flow in the one-fluid approximation, and they should be made part of the general set of equations that are solved in extreme black hole accretion and fully general numerical relativistic collapse simulations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Meier, DL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 19 TC 23 Z9 23 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 APR 10 PY 2004 VL 605 IS 1 BP 340 EP 349 DI 10.1086/382201 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WJ UT WOS:000220801700029 ER PT J AU Weisskopf, MC Wu, K Tennant, AF Swartz, DA Ghosh, KK AF Weisskopf, MC Wu, K Tennant, AF Swartz, DA Ghosh, KK TI On the nature of the bright short-period X-ray source in the Circinus galaxy field SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : eclipsing; black hole physics; galaxies : individual (Circinus); X-rays : binaries; X-rays : galaxies ID AM HERCULIS; BLACK-HOLES; CATACLYSMIC VARIABLES; RADIATIVE SHOCKS; CHANDRA; EMISSION; BINARIES; POPULATION; QUIESCENCE; CYGNUS-X-3 AB The spectrum and light curve of the bright X-ray source CG X-1 in the field of the Circinus galaxy are reexamined. Previous analyses have concluded that the source is an accreting black hole of mass greater than or similar to50 M., although it has been noted that the light curve resembles that of an AM Herculis system. Here we show that the short period and an assumed main-sequence companion constrain the mass of the companion to less than 1 M.. Furthermore, a possible eclipse seen during one of the Chandra observations and a subsequent XMM-Newton observation constrain the mass of the compact object to less than 60 M.. If such a system lies in the Circinus galaxy, then the accreting object must either radiate anisotropically or strongly violate the Eddington limit. Even if the emission is beamed, then the companion star that intercepts this flux during eclipse will be driven out of thermal equilibrium and evaporate within similar to10(3) yr. We find that the observations cannot rule out an AM Herculis system in the Milky Way and that such a system can account for the variations seen in the light curve. C1 NASA, Dept Space Sci, George C Marshall Space Flight Ctr, SD 50, Huntsville, AL 35812 USA. UCL, Mullard Space Sci Lab, Surrey RH5 6NT, England. NASA, USRA, George C Marshall Space Flight Ctr, SD 50, Huntsville, AL 35812 USA. RP NASA, Dept Space Sci, George C Marshall Space Flight Ctr, SD 50, Huntsville, AL 35812 USA. NR 38 TC 18 Z9 18 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2004 VL 605 IS 1 BP 360 EP 367 DI 10.1086/381307 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WJ UT WOS:000220801700031 ER PT J AU Smith, N Morse, JA Gull, TR Hillier, DJ Gehrz, RD Walborn, NR Bautista, M Collins, NR Corcoran, MF Damineli, A Hamann, F Hartman, H Johansson, S Stahl, O Weis, K AF Smith, N Morse, JA Gull, TR Hillier, DJ Gehrz, RD Walborn, NR Bautista, M Collins, NR Corcoran, MF Damineli, A Hamann, F Hartman, H Johansson, S Stahl, O Weis, K TI Kinematics and ultraviolet to infrared morphology of the inner homunculus of eta Carinae SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; stars : individual (eta Carinae); ultraviolet : stars ID HUBBLE-SPACE-TELESCOPE; LONG-PERIOD BINARY; X-RAY; PROPER MOTIONS; IMAGING POLARIMETRY; WEIGELT BLOBS; II EMISSION; OUTER SHELL; NEBULA; EJECTA AB We present the first ultraviolet and optical images of eta Car and its circumstellar Homunculus nebula, obtained with the Advanced Camera for Surveys/High Resolution Camera (ACS/HRC) on board the Hubble Space Telescope (HST). Compared to those at visual wavelengths, UV images reveal excess emission 0".1-0".6 from the central source along the minor axis that may emanate from the outer parts of eta Car's nonspherical stellar wind, which dominates the UV flux from eta Car. The UV emission fills the cavity inside a dust torus measured from infrared (IR) data; within 0".2 of the star the UV emission projects a morphology reminiscent of the IR torus, but it is a factor of 10 smaller. This "little torus'' seen in the UV may be related to the "Little Homunculus'' discovered recently, signifying recurrent mass ejections with the same geometry. Finally, we reexamine the kinematics of nebular condensations near the star (Weigelt objects C and D) in HST images and spectra obtained over the past decade. We measure heliocentric velocities slower than previous estimates, and from proper motions we derive an ejection date of 1908 +/- 12 yr, assuming linear motion. However, because of radiative acceleration, these objects may have been ejected earlier-perhaps during the 1890 outburst of eta Car. C1 Univ Colorado, Ctr Astrophys & Space Astron, UCB 389, Boulder, CO 80309 USA. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. NASA, Lab Astron & Space Sci, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Inst Venezolano Invest Cient, Ctr Fis, Caracas 1020A, Venezuela. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508090 Sao Paulo, Brazil. Univ Florida, Dept Astron, Gainesville, FL 32611 USA. Lund Univ, Lund Observ, SE-22100 Lund, Sweden. Univ Heidelberg, Landessternwarte Heidelberg Konigstuhl, D-69117 Heidelberg, Germany. Ruhr Univ Bochum, Inst Astron, D-44780 Bochum, Germany. RP Smith, N (reprint author), Univ Colorado, Ctr Astrophys & Space Astron, UCB 389, Boulder, CO 80309 USA. EM nathans@casa.colorado.edu RI Gull, Theodore/D-2753-2012; Damineli, Augusto/D-8210-2012; Hartman, Henrik/K-3113-2013 OI Gull, Theodore/0000-0002-6851-5380; Damineli, Augusto/0000-0002-7978-2994; NR 71 TC 51 Z9 51 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2004 VL 605 IS 1 BP 405 EP 424 DI 10.1086/382185 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WJ UT WOS:000220801700035 ER PT J AU Monnier, JD Millan-Gabet, R Tuthill, PG Traub, WA Carleton, NP du Foresto, VC Danchi, WC Lacasse, MG Morel, S Perrin, G Porro, IL Schloerb, FP Townes, CH AF Monnier, JD Millan-Gabet, R Tuthill, PG Traub, WA Carleton, NP du Foresto, VC Danchi, WC Lacasse, MG Morel, S Perrin, G Porro, IL Schloerb, FP Townes, CH TI High-resolution imaging of dust shells by using Keck aperture masking and the IOTA interferometer SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; instrumentation : interferometers; stars : AGB and post-AGB; stars : atmospheres; techniques : interferometric ID BISPECTRUM SPECKLE-INTERFEROMETRY; VY-CANIS-MAJORIS; HERBIG AE/BE STARS; BASE-LINE INTERFEROMETER; YOUNG STELLAR OBJECTS; M-GIANTS; RADIATIVE-TRANSFER; MIRA VARIABLES; PROPER MOTIONS; NML-CYGNI AB We present first results of an experiment to combine data from Keck aperture masking and the Infrared-Optical Telescope Array to image the circumstellar environments of evolved stars with similar to20 mas resolution. The unique combination of excellent Fourier coverage at short baselines and high-quality long-baseline fringe data allows us to determine the location and clumpiness of the innermost hot dust in the envelopes and to measure the diameters of the underlying stars themselves. We find evidence for large-scale inhomogeneities in some dust shells and also significant deviations from uniform brightness for the photospheres of the most evolved M stars. Deviations from spherically symmetric mass loss in the red supergiant NML Cyg could be related to recent evidence for dynamically important magnetic fields and/or stellar rotation. We point out that dust shell asymmetries, like those observed here, can qualitatively explain the difficulty recent workers have had in simultaneously fitting the broadband spectral energy distributions and high-resolution spatial information, without invoking unusual dust properties or multiple distinct shells (from hypothetical "superwinds''). This paper is the first to combine optical interferometry data from multiple facilities for imaging, and we discuss the challenges and potential for the future of this method, given current calibration and software limitations. C1 Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. CALTECH, Michelson Sci Ctr, Pasadena, CA 91125 USA. Univ Sydney, Dept Phys, Sydney, NSW 2006, Australia. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Observ Paris, F-92195 Meudon, France. NASA, Goddard Space Flight Ctr, Infrared Astrophys Branch, Greenbelt, MD 20771 USA. European So Observ, D-85748 Garching, Germany. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Univ Massachusetts, Dept Phys & Astron, Amherst, MA 01003 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP Univ Michigan, Dept Astron, 941 Dennison Bldg, Ann Arbor, MI 48109 USA. EM monnier@umich.edu OI Monnier, John D/0000-0002-3380-3307 NR 93 TC 89 Z9 89 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2004 VL 605 IS 1 BP 436 EP 461 DI 10.1086/382218 PN 1 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WJ UT WOS:000220801700037 ER PT J AU Wu, CS Reiner, MJ Yoon, PH Zheng, HN Wang, S AF Wu, CS Reiner, MJ Yoon, PH Zheng, HN Wang, S TI On low-frequency type III solar radio bursts observed in interplanetary space SO ASTROPHYSICAL JOURNAL LA English DT Article DE interplanetary medium; Sun : corona; Sun : radio radiation ID DIRECT AMPLIFICATION; HARMONIC EMISSION; ULYSSES OBSERVATIONS; MODEL INTERPRETATION; PLASMA FREQUENCY; ELECTRON-BEAMS; LANGMUIR-WAVES; LOW CORONA; WIND; GENERATION AB This article puts forth an alternative theory of interplanetary type III radio bursts, based on the cyclotron-maser instability. The model suggests that the radio emission is not generated in local interplanetary space but originates much closer to the corona. It postulates that the radiation remains trapped inside the density-depleted duct until it emerges out into free space at the end of the duct, which is located in the interplanetary space. With this model a number of outstanding problems associated with interplanetary type III bursts can be naturally resolved. Termination of type III bursts at low frequency can be explained by the fact that the ratio of plasma- to gyrofrequency, f(p) /f(g), in the source region exceeds the maximum allowable value for the maser instability. The low starting frequency can be explained by the fact that the parameter f(p) /f(g) in the source region falls below the minimum allowable value for the maser instability to operate. The rapid increase of temporal width of the dynamic spectrum near the termination frequency may be due to the low group speed associated with waves trapped inside the duct. C1 Univ Sci & Technol China, Dept Earth & Space Sci, Hefei 230026, Anhui, Peoples R China. Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. Catholic Univ Amer, Ctr Solar Phys & Space Weather, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wu, CS (reprint author), Univ Sci & Technol China, Dept Earth & Space Sci, Hefei 230026, Anhui, Peoples R China. RI Zheng, Huinan/A-1619-2010; Yoon, Peter/E-2395-2013 NR 38 TC 11 Z9 13 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2004 VL 605 IS 1 BP 503 EP 510 DI 10.1086/382144 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WJ UT WOS:000220801700042 ER PT J AU Yamauchi, Y Moore, RL Suess, ST Wang, H Sakurai, T AF Yamauchi, Y Moore, RL Suess, ST Wang, H Sakurai, T TI The magnetic structure of H alpha macrospicules in solar coronal holes SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : chromosphere; Sun : corona; Sun : magnetic fields ID X-RAY JETS; BRIGHT POINTS; QUIET SUN; ORIGIN; WIND; LIMB; ACCELERATION; RECONNECTION; NETWORK; FLARES AB Measurements by Ulysses in the high-speed polar solar wind have shown the wind to carry some fine-scale structures in which the magnetic field reverses direction by having a switchback fold in it. The lateral span of these magnetic switchbacks, translated back to the Sun, is of the scale of the lanes and cells of the magnetic network in which the open magnetic field of the polar coronal hole and polar solar wind are rooted. This suggests that the magnetic switchbacks might be formed from network-scale magnetic loops that erupt into the corona and then undergo reconnection with the open field. This possibility motivated us to undertake the study reported here of the structure of Halpha macrospicules observed at the limb in polar coronal holes, to determine whether a significant fraction of these eruptions appear to be erupting loops. From a search of the polar coronal holes in 6 days of image-processed full-disk Halpha movies from Big Bear Solar Observatory, we found a total of 35 macrospicules. Nearly all of these (32) were of one or the other of two different forms: 15 were in the form of an erupting loop, and 17 were in the form of a single-column spiked jet. The erupting-loop macrospicules are appropriate for producing the magnetic switchbacks in the polar wind. The spiked-jet macrospicules show the appropriate structure and evolution to be driven by reconnection between network-scale closed field (a network bipole) and the open field rooted against the closed field. This evidence for reconnection in a large fraction of our macrospicules (1) suggests that many spicules may be generated by similar but smaller reconnection events and (2) supports the view that coronal heating and solar wind acceleration in coronal holes and in quiet regions are driven by explosive reconnection events in the magnetic network. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. New Jersey Inst Technol, Big Bear Solar Observ, Big Bear City, CA 92314 USA. Natl Astron Observ Japan, Tokyo 1818588, Japan. RP NASA, George C Marshall Space Flight Ctr, Mail Code SD50, Huntsville, AL 35812 USA. EM Yohei.Yamauchi@msfc.nasa.gov; Ron.Moore@msfc.nasa.gov; Steven.T.Suess@nasa.gov; haimin@flare.njit.edu; sakurai@solar.mtk.nao.ac.jp NR 39 TC 21 Z9 21 U1 1 U2 7 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2004 VL 605 IS 1 BP 511 EP 520 DI 10.1086/381240 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WJ UT WOS:000220801700043 ER PT J AU Bonev, BP Penev, KM Sello, S AF Bonev, BP Penev, KM Sello, S TI Long-term solar variability and the solar cycle in the 21st century SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : activity ID PREDICTION; PERIOD; CALIBRATION; SUNSPOTS; FORECAST; MINIMUM AB We have examined the long-term trends in the solar variability that can be deduced from some indirect data and from optical records. We analyzed the radiocarbon measurements for the last 4500 years, based on dendrochronology, the Schove series for the last 1700 years, based on auroral records, and the Hoyt-Schatten series of group sunspot numbers. Focusing on periodicities near one and two centuries, which most likely have a solar origin, we conclude that the present epoch is at the onset of an upcoming local minimum in the long-term solar variability. There are some clues that the next minimum will be less deep than the Maunder minimum, but ultimately the relative depth between these two minima will be indicative of the amplitude change of the quasi two-century solar cycle. C1 Univ Toledo, Dept Phys & Astron, Ritter Astrophys Res Ctr, Toledo, OH 43606 USA. Bowling Green State Univ, Dept Phys & Astron, Bowling Green, OH 43403 USA. CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. Enel Res, Math & Phys Models, I-56122 Pisa, Italy. RP Bonev, BP (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 690, Greenbelt, MD 20771 USA. EM bbonev@lepvax.gsfc.nasa.gov; kpenev@cfa.harvard.edu; stefano.sello@enel.it OI Penev, Kaloyan/0000-0003-4464-1371 NR 37 TC 19 Z9 19 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2004 VL 605 IS 1 BP L81 EP L84 DI 10.1086/420695 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WK UT WOS:000220801800021 ER PT J AU Greenhill, LJ Gezari, DY Danchi, WC Najita, J Monnier, JD Tuthill, PG AF Greenhill, LJ Gezari, DY Danchi, WC Najita, J Monnier, JD Tuthill, PG TI High angular resolution mid-infrared imaging of young stars in Orion BN/KL SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; ISM : individual (Orion Kleinmann-Low); stars : formation; stars : pre-main-sequence ID MOLECULAR CLOUD; NEBULA CLUSTER; MASSIVE STARS; KL; ENVIRONMENT; EXTINCTION; REGION; IMAGES; IRC2 AB We present Keck Long Wavelength Spectrometer images of the Orion BN/KL star-forming region obtained in the first multiwavelength study to have 0."3 - 0."5 resolution from 4.7 to 22 mum. The young stellar objects designated infrared source n and radio source I are believed to dominate the BN/KL region. We have detected extended emission from a probable accretion disk around source n but infer a stellar luminosity on the order of only 2000 L,. Although source I is believed to be more luminous, we do not detect an infrared counterpart even at the longest wavelengths. However, we resolve the close-by infrared source, IRc2, into an arc of knots similar to10(3) AU long at all wavelengths. Although the physical relation of source I to IRc2 remains ambiguous, we suggest that these sources mark a high-density core (10(7) - 10(8) pc(-3) over similar to10(3) AU) within the larger BN/KL star-forming cluster. The high density may be a consequence of the core being young and heavily embedded. We suggest that the energetics of the BN/KL region may be dominated by this cluster core rather than one or two individual sources. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Opt Astron Observ, Tucson, AZ 85719 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. RP Greenhill, LJ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM greenhill@cfa.harvard.edu OI Monnier, John D/0000-0002-3380-3307 NR 34 TC 46 Z9 46 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2004 VL 605 IS 1 BP L57 EP L60 DI 10.1086/386544 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WK UT WOS:000220801800015 ER PT J AU Liang, MC Seager, S Parkinson, CD Lee, AYT Yung, YL AF Liang, MC Seager, S Parkinson, CD Lee, AYT Yung, YL TI On the insignificance of photochemical hydrocarbon aerosols in the atmospheres of close-in extrasolar giant planets SO ASTROPHYSICAL JOURNAL LA English DT Article DE planetary systems; radiative transfer; stars : atmospheres; stars : individual (HD 209458) ID HD 209458B; POLAR ATMOSPHERE; JOVIAN PLANETS; HAZE FORMATION; BROWN DWARFS; JUPITER; SPECTROPHOTOMETRY; HD-209458; SPECTRA; OXYGEN AB The close-in extrasolar giant planets (CEGPs) reside in irradiated environments much more intense than that of the giant planets in our solar system. The high UV irradiance strongly influences their photochemistry, and the general current view believed that this high UV flux will greatly enhance photochemical production of hydrocarbon aerosols. In this Letter, we investigate hydrocarbon aerosol formation in the atmospheres of CEGPs. We find that the abundances of hydrocarbons in the atmospheres of CEGPs are significantly less than that of Jupiter except for models in which the CH 4 abundance is unreasonably high ( as high as CO) for the hot ( effective temperatures greater than or similar to 1000 K) atmospheres. Moreover, the hydrocarbons will be condensed out to form aerosols only when the temperature-pressure profiles of the species intersect with the saturation profiles - a case almost certainly not realized in the hot CEGPs' atmospheres. Hence our models show that photochemical hydrocarbon aerosols are insignificant in the atmospheres of CEGPs. In contrast, Jupiter and Saturn have a much higher abundance of hydrocarbon aerosols in their atmospheres that are responsible for strong absorption shortward of 600 nm. Thus the insignificance of photochemical hydrocarbon aerosols in the atmospheres of CEGPs rules out one class of models with low albedos and featureless spectra shortward of 600 nm. C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NASA, Astrobiol Inst, Washington, DC USA. RP Liang, MC (reprint author), CALTECH, Div Geol & Planetary Sci, 1201 E Calif Blvd, Pasadena, CA 91125 USA. NR 33 TC 51 Z9 51 U1 2 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2004 VL 605 IS 1 BP L61 EP L64 DI 10.1086/392509 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 811WK UT WOS:000220801800016 ER PT J AU Wang, HP Tsai, JSH Yi, YI Shieh, LS AF Wang, HP Tsai, JSH Yi, YI Shieh, LS TI Lifted digital redesign of observer-based tracker for a sampled-data system SO INTERNATIONAL JOURNAL OF SYSTEMS SCIENCE LA English DT Article ID CONTROLLERS; DESIGN AB A lifted prediction-based digital redesign method to discretize an analogue tracker for a sampled-data systems is presented. The developed lifted digital redesign method is then used to construct a full/reduced-order digital observer. The developed lifted observer-based digital tracker improves the intersample behaviour of the digitally redesigned sampled-data systems. An illustrative example of a hybrid multivariable system demonstrates the effectiveness of the proposed method . C1 Natl Cheng Kung Univ, Control Syst Lab, Dept Elect Engn, Tainan 701, Taiwan. Boeing Co, NASA Syst, Houston, TX 77059 USA. Univ Houston, Dept Elect & Comp Engn, Houston, TX 77204 USA. RP Tsai, JSH (reprint author), Natl Cheng Kung Univ, Control Syst Lab, Dept Elect Engn, Tainan 701, Taiwan. EM shtsai@mail.ncku.edu.tw NR 15 TC 5 Z9 5 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0020-7721 J9 INT J SYST SCI JI Int. J. Syst. Sci. PD APR 10 PY 2004 VL 35 IS 4 BP 255 EP 271 DI 10.1080/00207720410001714815 PG 17 WC Automation & Control Systems; Computer Science, Theory & Methods; Operations Research & Management Science SC Automation & Control Systems; Computer Science; Operations Research & Management Science GA 831EY UT WOS:000222177800005 ER PT J AU Sutter, B Moore, JM Zent, AP AF Sutter, B Moore, JM Zent, AP TI Examining the sediments and soils of Gusev Crater with the Athena science payload SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Gusev Crater; Mars; sediments ID MARS PATHFINDER; MARTIAN SOIL; MAADIM-VALLIS; EXPERIMENTAL ABRASION; CHEMICAL-COMPOSITION; HYDROTHERMAL ORIGIN; TERRESTRIAL ANALOG; LANDING SITE; BASALT; SURFACE AB [1] Gusev Crater has been proposed to contain lacustrine and/or fluvial sediments; however, eolian or volcanic sediments, global dust, and locally produced soils may also be present. This work describes the use of the Athena instrument package to evaluate the environment in which sampled materials were deposited in Gusev Crater. Sedimentary or soil deposits can be sampled by examining materials that were ( 1) excavated by impact events, ( 2) revealed by wind deflation, or ( 3) exposed by spinning the rover wheels. Specific observations can be diagnostic of a depositional environment. For instance, Pancam images of thin ( e. g., 5 cm) planar layers of phyllosilicates and/or evaporites (as determined by Mini-TES) would suggest lacustrine sediments. Layered sediments ( e. g., trough cross bed) with rounded particles (> 4 mm) would suggest fluvial activity. Eolian sediments may have planar or cross-planar layers of well-sorted grains (similar to200 mum). Parallel bed deposits consisting of glass observable by Microscopic Imager would indicate volcanic ash. Soil bulk chemistry reported by Alpha Particle X-ray Spectrometer that is similar to the Viking and Mars Pathfinder soils would indicate global dust. Mini-TES should only detect primary mineralogies in physically weathered soils, whereas chemically weathered soils may contain carbonates, sulfates, and/or phyllosilicates. Although some characteristics are unique to a sediment or soil deposit, different deposit types can have similar characteristics ( e. g., planar layering). Determining the depositional history of material in Gusev will require the integration of measurements from several instruments and careful geologic reasoning by the investigators. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. EM bsutter@mail.arc.nasa.gov NR 97 TC 1 Z9 1 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 10 PY 2004 VL 109 IS E4 AR E04002 DI 10.1029/2003JE002157 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 813PK UT WOS:000220918800001 ER PT J AU Lohmann, D Mitchell, KE Houser, PR Wood, EF Schaake, JC Robock, A Cosgrove, BA Sheffield, J Duan, QY Luo, LF Higgins, RW Pinker, RT Tarpley, JD AF Lohmann, D Mitchell, KE Houser, PR Wood, EF Schaake, JC Robock, A Cosgrove, BA Sheffield, J Duan, QY Luo, LF Higgins, RW Pinker, RT Tarpley, JD TI Streamflow and water balance intercomparisons of four land surface models in the North American Land Data Assimilation System project SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE LDAS; streamflow; water balance ID RIVER-BASIN EXPERIMENT; SOUTHERN GREAT-PLAINS; PARAMETERIZATION SCHEMES; NLDAS PROJECT; PILPS 2(D); RUNOFF; PHASE; SOIL; SIMULATION; HYDROLOGY AB [1] This paper is part of a series of papers about the multi-institutional North American Land Data Assimilation System (NLDAS) project. It compares and evaluates streamflow and water balance results from four different land surface models (LSMs) within the continental United States. These LSMs have been run for the retrospective period from 1 October 1996 to 30 September 1999 forced by atmospheric observations from the Eta Data Assimilation System (EDAS) analysis, measured precipitation, and satellite-derived downward solar radiation. These model runs were performed on a common 1/8degrees latitude-longitude grid and used the same database for soil and vegetation classifications. We have evaluated these simulations using U.S. Geological Survey (USGS) measured daily streamflow data for 9 large major basins and 1145 small- to medium-sized basins from 23 km(2) to 10,000 km(2) distributed over the NLDAS domain. Model runoff was routed with a common distributed and a lumped optimized linear routing model. The diagnosis of the model water balance results demonstrates strengths and weaknesses in the models, our insufficient knowledge of ad hoc parameters used for the model runs, the interdependence of model structure and model physics, and the lack of good forcing data in parts of the United States, especially in regions with extended snow cover. Overall, the differences between the LSM water balance terms are of the same magnitude as the mean water balance terms themselves. The modeled mean annual runoff shows large regional differences by a factor of up to 4 between models. The corresponding difference in mean annual evapotranspiration is about a factor of 2. The analysis of runoff timing for the LSMs demonstrates the importance of correct snowmelt timing, where the resulting differences in streamflow timing can be up to four months. Runoff is underestimated by all LSMs in areas with significant snowfall. C1 Natl Weather Serv, Environm Modeling Ctr, Natl Ctr Environm Predict, NOAA, Camp Springs, MD 20746 USA. NASA, Sci Applicat Int Corp, Hydrol Sci Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Princeton Univ, Dept Civil & Environm Engn, Princeton, NJ 08544 USA. Natl Weather Serv, Off Hydrol Dev, NOAA, Silver Spring, MD 20910 USA. Rutgers State Univ, Dept Environm Sci, New Brunswick, NJ 08901 USA. Natl Weather Serv, Climate Predict Ctr, Natl Ctr Environm Predict, NOAA, Camp Springs, MD 20746 USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Camp Springs, MD 20746 USA. RP Lohmann, D (reprint author), Natl Weather Serv, Environm Modeling Ctr, Natl Ctr Environm Predict, NOAA, 5200 Auth Rd, Camp Springs, MD 20746 USA. EM dag.lohmann@noaa.gov; kenneth.mitchell@noaa.gov; paul.r.houser@nasa.gov; efwood@princeton.edu; john.schaake@noaa.gov; robock@envsci.rutgers.edu; brian.cosgrove@gsfc.nasa.gov; justin@princeton.edu; qingyun.duan@noaa.gov; lluo@princeton.edu; wayne.higgins@noaa.gov; pinker@atmos.umd.edu; dan.tarpley@noaa.gov RI Sheffield, Justin/A-6388-2008; Luo, Lifeng/C-8734-2009; Pinker, Rachel/F-6565-2010; Houser, Paul/J-9515-2013; Duan, Qingyun/C-7652-2011; Robock, Alan/B-6385-2016 OI Houser, Paul/0000-0002-2991-0441; Duan, Qingyun/0000-0001-9955-1512; NR 50 TC 88 Z9 88 U1 0 U2 18 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 9 PY 2004 VL 109 IS D7 AR D07S91 DI 10.1029/2003JD003517 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 813OP UT WOS:000220916700001 ER PT J AU McCarthy, MC Boering, KA Rahn, T Eiler, JM Rice, AL Tyler, DC Schauffler, S Atlas, E Johnson, DG AF McCarthy, MC Boering, KA Rahn, T Eiler, JM Rice, AL Tyler, DC Schauffler, S Atlas, E Johnson, DG TI The hydrogen isotopic composition of water vapor entering the stratosphere inferred from high-precision measurements of delta D-CH4 and delta D-H-2 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE hydrogen isotopic composition; water vapor; stratosphere; tropical troposphere layer ID TROPICAL TROPOPAUSE LAYER; INFRARED SOLAR SPECTRA; IN-SITU MEASUREMENTS; HORIZONTAL TRANSPORT; LINE POSITIONS; BALLOON-BORNE; POLAR VORTEX; CH4; METHANE; HDO AB [1] The hydrogen isotopic composition of water vapor entering the stratosphere provides an important constraint on the mechanisms for dehydration of air ascending through the tropical tropopause layer. We have inferred the annual mean hydrogen isotopic composition of water vapor entering the stratosphere (or deltaD-H2O0) for the mid to late 1990s based on high-precision measurements of the hydrogen isotopic compositions of stratospheric H-2 and CH4 from whole air samples collected on the NASA ER-2 aircraft between 1996 and 2000 and remote observations of deltaD-H2O from the FIRS-2 far infrared spectrometer. We calculate an annual mean value for deltaD-H2O0 of - 653 (+ 24/ - 25)parts per thousand relative to Vienna standard mean ocean water (VSMOW). Previous inferences from balloon-borne and spacecraft remote-sensing observations are similar to20parts per thousand lighter than the value from this analysis. We attribute the difference to an underestimation of deuterium in the molecular H-2 reservoir in earlier work. This precise and more accurate value for the annual mean deltaD-H2O0 will be useful as a 1990' s benchmark for detecting future changes in the details of the dehydration of air due to the impact of climate change on convection intensity, cloud microphysics, or tropical tropopause layer temperatures. In addition, we report a value for the total deuterium content in the three main stratospheric hydrogen reservoirs HDO, HD, and CH3D of 1.60 (+ 0.02/-0.03) ppbv. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Earth & Planetary Sci, Berkeley, CA 94720 USA. Lawrence Livermore Natl Lab, Div Earth Sci, Livermore, CA USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. NASA, Laser & Electroopt Branch, Langley Res Ctr, Hampton, VA 23681 USA. RP McCarthy, MC (reprint author), Sonoma Technol Inc, Petaluma, CA 94954 USA. EM boering@cchem.berkeley.edu; eiler@gps.caltech.edu; styler@uci.edu; eatlas@rsmas.miami.edu; david.g.johnson@nasa.gov RI McCarthy, Michael/E-5970-2010; Rahn, Thom/C-5211-2012; Atlas, Elliot/J-8171-2015 NR 58 TC 19 Z9 19 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 APR 9 PY 2004 VL 109 IS D7 AR D07304 DI 10.1029/2003JD004003 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 813OP UT WOS:000220916700005 ER PT J AU Mitchell, KE Lohmann, D Houser, PR Wood, EF Schaake, JC Robock, A Cosgrove, BA Sheffield, J Duan, QY Luo, LF Higgins, RW Pinker, RT Tarpley, JD Lettenmaier, DP Marshall, CH Entin, JK Pan, M Shi, W Koren, V Meng, J Ramsay, BH Bailey, AA AF Mitchell, KE Lohmann, D Houser, PR Wood, EF Schaake, JC Robock, A Cosgrove, BA Sheffield, J Duan, QY Luo, LF Higgins, RW Pinker, RT Tarpley, JD Lettenmaier, DP Marshall, CH Entin, JK Pan, M Shi, W Koren, V Meng, J Ramsay, BH Bailey, AA TI The multi-institution North American Land Data Assimilation System (NLDAS): Utilizing multiple GCIP products and partners in a continental distributed hydrological modeling system SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE land modeling; land data assimilation; surface energy budget ID SURFACE PARAMETERIZATION SCHEMES; RIVER-BASIN EXPERIMENT; SOUTHERN GREAT-PLAINS; MESOSCALE ETA-MODEL; FIFE DATA; PROJECT; WATER; PHASE; SNOW; PRECIPITATION AB [1] Results are presented from the multi-institution partnership to develop a real-time and retrospective North American Land Data Assimilation System (NLDAS). NLDAS consists of ( 1) four land models executing in parallel in uncoupled mode, ( 2) common hourly surface forcing, and ( 3) common streamflow routing: all using a 1/8degrees grid over the continental United States. The initiative is largely sponsored by the Global Energy and Water Cycle Experiment (GEWEX) Continental-Scale International Project ( GCIP). As the overview for nine NLDAS papers, this paper describes and evaluates the 3-year NLDAS execution of 1 October 1996 to 30 September 1999, a period rich in observations for validation. The validation emphasizes ( 1) the land states, fluxes, and input forcing of four land models, ( 2) the application of new GCIP-sponsored products, and ( 3) a multiscale approach. The validation includes ( 1) mesoscale observing networks of land surface forcing, fluxes, and states, ( 2) regional snowpack measurements, ( 3) daily streamflow measurements, and ( 4) satellite-based retrievals of snow cover, land surface skin temperature (LST), and surface insolation. The results show substantial intermodel differences in surface evaporation and runoff ( especially over nonsparse vegetation), soil moisture storage, snowpack, and LST. Owing to surprisingly large intermodel differences in aerodynamic conductance, intermodel differences in midday summer LST were unlike those expected from the intermodel differences in Bowen ratio. Last, anticipating future assimilation of LST, an NLDAS effort unique to this overview paper assesses geostationary-satellite-derived LST, determines the latter to be of good quality, and applies the latter to validate modeled LST. C1 Natl Weather Serv, Environm Modeling Ctr, Natl Ctr Environm Predict, NOAA, Camp Springs, MD 20746 USA. NASA, Hydrol Sci Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Data Assimilat Off, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Princeton Univ, Dept Civil & Environm Engn, Princeton, NJ 08544 USA. Natl Weather Serv, Off Hydrol Dev, NOAA, Silver Spring, MD 20910 USA. Rutgers State Univ, Dept Environm Sci, New Brunswick, NJ 08901 USA. Natl Weather Serv, Climate Predict Ctr, Natl Ctr Environm Predict, NOAA, Camp Springs, MD 20746 USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Camp Springs, MD 20746 USA. Univ Washington, Dept Civil & Environm Engn, Seattle, WA 98195 USA. RP Mitchell, KE (reprint author), Natl Weather Serv, Environm Modeling Ctr, Natl Ctr Environm Predict, NOAA, 5200 Auth Rd, Camp Springs, MD 20746 USA. EM kenneth.mitchell@noaa.gov; dag.lohmann@noaa.gov; paul.r.houser@nasa.gov; efwood@princeton.edu; john.schaake@noaa.gov; robock@envsci.rutgers.edu; brian.cosgrove@gsfc.nasa.gov; justin@princeton.edu; qingyun.duan@noaa.gov; lluo@princeton.edu; wayne.higgins@noaa.gov; pinker@atmos.umd.edu; dan.tarpley@noaa.gov; dennisl@u.washington.edu; curtis@atmos.colostate.edu; jared.entin@gsfc.nasa.gov; mpan@princeton.edu; wshi@ncep.noaa.gov; victor.koren@noaa.gov; jesse.meng@noaa.gov; bruce.r.ramsay@noaa.gov; baileya@comcast.net RI Sheffield, Justin/A-6388-2008; Luo, Lifeng/C-8734-2009; Pinker, Rachel/F-6565-2010; Pan, Ming/B-6841-2011; Shi, Wei/F-5625-2010; Houser, Paul/J-9515-2013; lettenmaier, dennis/F-8780-2011; Duan, Qingyun/C-7652-2011; Robock, Alan/B-6385-2016 OI Pan, Ming/0000-0003-3350-8719; Houser, Paul/0000-0002-2991-0441; lettenmaier, dennis/0000-0003-3317-1327; Duan, Qingyun/0000-0001-9955-1512; NR 66 TC 248 Z9 249 U1 4 U2 61 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 9 PY 2004 VL 109 IS D7 AR D07S90 DI 10.1029/2003JD003823 PG 32 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 813OP UT WOS:000220916700003 ER PT J AU Yang, JY Comiso, J Walsh, D Krishfield, R Honjo, S AF Yang, JY Comiso, J Walsh, D Krishfield, R Honjo, S TI Storm-driven mixing and potential impact on the Arctic Ocean SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE Arctic Ocean; mixing; storm; upper ocean ID SEA-ICE MOTION; NORTH-ATLANTIC OSCILLATION; LEVEL PRESSURE; TEMPERATURE; VARIABILITY; HALOCLINE; ANOMALIES; REGIMES; CLIMATE; LAYER AB [1] Observations of the ocean, atmosphere, and ice made by Ice-Ocean Environmental Buoys indicate that mixing events reaching the depth of the halocline have occurred in various regions in the Arctic Ocean. Our analysis suggests that these mixing events were mechanically forced by intense storms moving across the buoy sites. In this study, we analyzed these mixing events in the context of storm developments that occurred in the Beaufort Sea and in the general area just north of Fram Strait, two areas with quite different hydrographic structures. The Beaufort Sea is strongly influenced by inflow of Pacific water through Bering Strait, while the area north of Fram Strait is directly affected by the inflow of warm and salty North Atlantic water. Our analyses of the basin-wide evolution of the surface pressure and geostrophic wind fields indicate that the characteristics of the storms could be very different. The buoy-observed mixing occurred only in the spring and winter seasons when the stratification was relatively weak. This indicates the importance of stratification, although the mixing itself was mechanically driven. We also analyze the distribution of storms, both the long-term climatology and the patterns for each year in the past 2 decades. The frequency of storms is also shown to be correlated (but not strongly) to Arctic Oscillation indices. This study indicates that the formation of new ice that leads to brine rejection is unlikely the mechanism that results in the type of mixing that could overturn the halocline. On the other hand, synoptic-scale storms can force mixing deep enough to the halocline and thermocline layer. Despite a very stable stratification associated with the Arctic halocline, the warm subsurface thermocline water is not always insulated from the mixed layer. C1 Woods Hole Oceanog Inst, Dept Phys Oceanog, Woods Hole, MA 02543 USA. NASA, Lab Hydrospher Proc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Alaska, Int Arctic Res Ctr, Fairbanks, AK 99775 USA. Woods Hole Oceanog Inst, Dept Geol & Geophys, Woods Hole, MA 02543 USA. RP Yang, JY (reprint author), Woods Hole Oceanog Inst, Dept Phys Oceanog, Woods Hole, MA 02543 USA. EM jyang@whoi.edu NR 29 TC 26 Z9 26 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9275 EI 2169-9291 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD APR 9 PY 2004 VL 109 IS C4 AR C04008 DI 10.1029/2001JC001248 PG 18 WC Oceanography SC Oceanography GA 813OY UT WOS:000220917600001 ER PT J AU Taguchi, S Collier, MR Moore, TE Fok, MC Singer, HJ AF Taguchi, S Collier, MR Moore, TE Fok, MC Singer, HJ TI Response of neutral atom emissions in the low-latitude and high-latitude magnetosheath direction to the magnetopause motion under extreme solar wind conditions SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE cusp; neutral atoms; magnetopause; magnetosheath; solar wind; extreme conditions ID FIELD; SHAPE; PRESSURE; IMAGE; ENA AB [1] On 11 April 2001 the high velocity and density of the solar wind and the strong southward interplanetary magnetic field moved the dayside magnetopause inside of geosynchronous orbit. The Low Energy Neutral Atom (LENA) imager on the Imager for Magnetopause-to-Aurora Global Exploration ( IMAGE) spacecraft in the magnetosphere observed significant emission in the magnetosheath direction. The total neutral atom flux from the dayside region, ignoring the neutral solar wind flux directly from the Sun, shows a threefold enhancement, and each of the three increases is coincident with the occurrence of the magnetopause inside 6.6 R-E. Observations by LENA also show that emission in the direction of the low-latitude and high-latitude magnetosheath is modulated in such a manner that the sources shift earthward/sunward and equatorward/ poleward in the low-latitude and high-latitude sheath, respectively. A model based on the distributions of the sheath flux and of the number density of the hydrogen exosphere explains these characteristics as a result of the motion of the magnetopause having an indentation at the cusp, suggesting a means for monitoring the cusp motion using IMAGE/LENA. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. NOAA, Space Environm Ctr, Boulder, CO 80303 USA. RP Taguchi, S (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Code 692, Greenbelt, MD 20771 USA. EM taguchi@ice.uec.ac.jp; mcollier@pop600.gsfc.nasa.gov; thomas.e.moore@gsfc.nasa.gov; mei-ching.fok@gsfc.nasa.gov; hsinger@sec.noaa.gov RI Moore, Thomas/D-4675-2012; Fok, Mei-Ching/D-1626-2012; Collier, Michael/I-4864-2013 OI Moore, Thomas/0000-0002-3150-1137; Collier, Michael/0000-0001-9658-6605 NR 21 TC 14 Z9 14 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-SPACE JI J. Geophys. Res-Space Phys. PD APR 9 PY 2004 VL 109 IS A4 AR A04208 DI 10.1029/2003JA010147 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 813PT UT WOS:000220919700001 ER PT J AU Marcy, TP Fahey, DW Gao, RS Popp, PJ Richard, EC Thompson, TL Rosenlof, KH Ray, EA Salawitch, RJ Atherton, CS Bergmann, DJ Ridley, BA Weinheimer, AJ Loewenstein, M Weinstock, EM Mahoney, MJ AF Marcy, TP Fahey, DW Gao, RS Popp, PJ Richard, EC Thompson, TL Rosenlof, KH Ray, EA Salawitch, RJ Atherton, CS Bergmann, DJ Ridley, BA Weinheimer, AJ Loewenstein, M Weinstock, EM Mahoney, MJ TI Quantifying stratospheric ozone in the upper troposphere with in situ measurements of HCl SO SCIENCE LA English DT Article ID LOWERMOST STRATOSPHERE; TRACER CORRELATIONS; HYDROGEN-CHLORIDE; AIRCRAFT; EXCHANGE; ALTITUDE; BALLOON; ER-2; HNO3; NOY AB We have developed a chemical ionization mass spectrometry technique for precise in situ measurements of hydrochloric acid (HCl) from a high-altitude aircraft. In measurements at subtropical latitudes, minimum HCl values found in the upper troposphere ( UT) were often near or below the detection limit of the measurements (0.005 parts per billion by volume), indicating that background HCl values are much lower than a global mean estimate. However, significant abundances of HCl were observed in many UT air parcels, as a result of stratosphere-to-troposphere transport events. We developed a method for diagnosing the amount of stratospheric ozone in these UT parcels using the compact linear correlation of HCl with ozone found throughout the lower stratosphere (LS). Expanded use of this method will lead to improved quanti. cation of cross-tropopause transport events and validation of global chemical transport models. C1 NOAA, Aeron Lab, Boulder, CO 80305 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Lawrence Livermore Natl Lab, Div Atmospher Sci, Livermore, CA 94550 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Harvard Univ, Cambridge, MA 02138 USA. RP Marcy, TP (reprint author), NOAA, Aeron Lab, Boulder, CO 80305 USA. EM tmarcy@al.noaa.gov RI Salawitch, Ross/B-4605-2009; Bergmann, Daniel/F-9801-2011; Gao, Ru-Shan/H-7455-2013; Ray, Eric/D-5941-2013; Rosenlof, Karen/B-5652-2008; Fahey, David/G-4499-2013 OI Salawitch, Ross/0000-0001-8597-5832; Bergmann, Daniel/0000-0003-4357-6301; Ray, Eric/0000-0001-8727-9849; Rosenlof, Karen/0000-0002-0903-8270; Fahey, David/0000-0003-1720-0634 NR 36 TC 38 Z9 40 U1 1 U2 10 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD APR 9 PY 2004 VL 304 IS 5668 BP 261 EP 265 DI 10.1126/science.1093418 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 810QS UT WOS:000220719400038 PM 15073371 ER PT J AU Zhao, JJ Park, HK Han, J Lu, JP AF Zhao, JJ Park, HK Han, J Lu, JP TI Electronic properties of carbon nanotubes with covalent sidewall functionalization SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID BROKEN SYMMETRY; GLOW-DISCHARGE; FLUORINATION; ROPES; CONDUCTANCE; PSEUDOGAPS; ADSORPTION; HYDROGEN; DEFECTS; STATES AB We show that covalent sidewall functionalization of single-wall nanotubes leads to drastic changes of nanotube electronic states near the Fermi level. The sp(3) hybridization between the functional group and nanotube induces an impurity state near the Fermi level. The impurity state is found to be extended over a large distance (> 1 nm) even though the structural deformation is confined to the vicinity of the functionalizing site. Thus, dramatic changes in the conductive properties of the nanotube can be expected even if the concentration of functionalization molecules is small. This effect provides an effective pathway for band structure engineering, nanoelectronic device, and sensor applications through covalent sidewall functionalization. C1 Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. NASA, Ames Res Ctr, Eloret Corp, Santa Clara, CA 95051 USA. RP Lu, JP (reprint author), Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. EM jpl@physics.unc.edu RI Zhao, Jijun/I-6030-2015 NR 48 TC 197 Z9 199 U1 4 U2 37 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD APR 8 PY 2004 VL 108 IS 14 BP 4227 EP 4230 DI 10.1021/jp036814u PG 4 WC Chemistry, Physical SC Chemistry GA 809MH UT WOS:000220640300002 ER PT J AU Schmidt, GA Mann, ME AF Schmidt, GA Mann, ME TI Reply to comment on "Ground vs. surface air temperature trends: Implications for borehole surface temperature reconstructions'' by D. Chapman et al. SO GEOPHYSICAL RESEARCH LETTERS LA English DT Editorial Material C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Ctr Climate Syst Res, New York, NY 10025 USA. Univ Virginia, Dept Environm Sci, Charlottesville, VA 22902 USA. RP Schmidt, GA (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM gschmidt@giss.nasa.gov; mann@virginia.edu RI Schmidt, Gavin/D-4427-2012; Mann, Michael/B-8472-2017 OI Schmidt, Gavin/0000-0002-2258-0486; Mann, Michael/0000-0003-3067-296X NR 10 TC 19 Z9 19 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 7 PY 2004 VL 31 IS 7 AR L07206 DI 10.1029/2003GL019144 PG 2 WC Geosciences, Multidisciplinary SC Geology GA 813NY UT WOS:000220915000004 ER PT J AU Leventis, N Yang, JH Fabrizio, EF Rawashdeh, AMM Oh, WS Sotiriou-Leventis, C AF Leventis, N Yang, JH Fabrizio, EF Rawashdeh, AMM Oh, WS Sotiriou-Leventis, C TI Redox-active star molecules incorporating the 4-benzoylpyridinium cation: Implications for the charge transfer efficiency along branches vs across the perimeter in dendrimers SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ULTRAFAST CYCLIC VOLTAMMETRY; 2-ELECTRON; CORE C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Missouri, Dept Chem, Rolla, MO 65409 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. RP Leventis, N (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd MS 46-1, Cleveland, OH 44135 USA. EM Nicholas.Leventis@nasa.gov; cslevent@umr.edu NR 17 TC 16 Z9 16 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD APR 7 PY 2004 VL 126 IS 13 BP 4094 EP 4095 DI 10.1021/ja0390247 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 809LB UT WOS:000220637100022 PM 15053584 ER EF