FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Allen, DR Bevilacqua, RM Nedoluha, GE Randall, CE Manney, GL AF Allen, DR Bevilacqua, RM Nedoluha, GE Randall, CE Manney, GL TI Unusual stratospheric transport and mixing during the 2002 Antarctic winter SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OZONE HOLE; TROPOSPHERE AB Unusually large planetary wave activity in the 2002 Antarctic winter stratosphere weakened and warmed the polar vortex. Three minor warmings during August and early September preceded a late-September major warming when the middle stratospheric zonal winds reversed to easterly and the polar temperature increased by an additional 25 K. Polar Ozone and Aerosol Measurement (POAM III) ozone data at high southern latitudes show unusually large variability in 2002 compared to previous POAM III years (1998-2001). Analyses of air parcel transport indicate this variability is caused by large-scale isentropic transport. Diagnostics of transport and mixing show that during the major warming the lower stratospheric vortex remained intact, while the middle stratospheric vortex split into two pieces; one piece rapidly mixed with extravortex air, while the other returned to the pole as a much weaker and smaller vortex. C1 USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. New Mexico Highlands Univ, Dept Nat Sci, Las Vegas, NM 87701 USA. RP USN, Res Lab, Remote Sensing Div, 4555 Overlook Ave SW, Washington, DC 20375 USA. EM drallen@nrl.navy.mil; bevilacqua@nrl.navy.mil; nedoluha@nrl.navy.mil; randall@lasp.colorado.edu; manney@mls.jpl.nasa.gov RI Randall, Cora/L-8760-2014 OI Randall, Cora/0000-0002-4313-4397 NR 17 TC 76 Z9 76 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 17 PY 2003 VL 30 IS 12 AR 1599 DI 10.1029/2003GL017117 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 693WZ UT WOS:000183742500002 ER PT J AU Kaufmann, RK Zhou, L Tucker, CJ Slayback, D Shabanov, NV Myneni, RB AF Kaufmann, RK Zhou, L Tucker, CJ Slayback, D Shabanov, NV Myneni, RB TI Reply to comment by M. Lanfredi et al. to "Variations in northern vegetation activity inferred from satellite data of vegetation index during 1981 to 1999" by L. Zhou et al. SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Editorial Material DE NDVI; temperature; growing season; climate change ID RESPONSES; CLIMATE C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Syst Sci & Applicat Inc, Greenbelt, MD USA. RP Kaufmann, RK (reprint author), Boston Univ, Dept Geog, 675 Commonwealth Ave, Boston, MA 02215 USA. EM kaufmann@crsa.bu.edu; lmzhou@eas.gatech.edu; compton@kratmos.gsfc.nasa.gov; dan@manyu.gsfc; shabanov@crsa.bu.edu; rmyneni@crsa.bu.edu RI Slayback, Daniel/E-7465-2011; Myneni, Ranga/F-5129-2012 NR 12 TC 0 Z9 0 U1 1 U2 12 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 17 PY 2003 VL 108 IS D12 AR 4347 DI 10.1029/2002JD003287 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 693XR UT WOS:000183744100004 ER PT J AU Muller, D Mattis, I Wandinger, U Ansmann, A Althausen, D Dubovik, O Eckhardt, S Stohl, A AF Muller, D Mattis, I Wandinger, U Ansmann, A Althausen, D Dubovik, O Eckhardt, S Stohl, A TI Saharan dust over a central European EARLINET-AERONET site: Combined observations with Raman lidar and Sun photometer SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE microphysical properties; optical properties; Raman lidar; Saharan dust; Sun photometer ID TO-BACKSCATTER RATIO; AEROSOL OPTICAL-PROPERTIES; AIRBORNE MINERAL AEROSOLS; SKY RADIANCE MEASUREMENTS; LIGHT-SCATTERING; ATMOSPHERIC TURBIDITY; TROPOSPHERIC AEROSOL; SIZE DISTRIBUTION; ICE CRYSTALS; DESERT-DUST AB [1] Combined observations with an advanced aerosol water-vapor temperature Raman lidar and a Sun photometer are used for a detailed characterization of geometrical and optical properties of a continental-scale Saharan dust event observed over Leipzig ( 51.3 degreesN, 12.4 degreesE), Germany, from 13 to 15 October 2001. The Raman lidar is part of the European Aerosol Research Lidar Network (EARLINET). Automatic observations of aerosol optical depth and sky brightness are made with the Sun photometer in the framework of the worldwide operating Aerosol Robotic Network (AERONET). The dust plume reached a top height of 6000 m. Sun photometer and lidar observations showed a constant increase of columnar optical depth at 532 nm from 0.25 on 13 October 2001 to a maximum of similar to0.63 on 14 October 2001. According to observations with lidar, up to 90% of the optical depth at the wavelength of 532 nm was contributed by the dust layer above 1000-m height. Angstrom exponents from Sun photometer observations between 380 and 1020 nm were similar to0.45 at the beginning of the dust period, and dropped to minimum values of 0.14 during the peak of the dust outbreak. Vertically resolved Angstrom exponents derived from lidar profiles of the extinction coefficients at 355 and 532 nm showed a strong variability with values as low as -0.2 in the center of the dust plume. Below 1000-m height column-averaged Angstrom exponents strongly varied between 1.0 in the beginning of the dust period and 0.39 on 14 October 2001 when the dust penetrated into the boundary layer. Comparison of column-averaged optical depth and Angstrom exponents derived from lidar and Sun photometer observations showed excellent agreement. Particle depolarization ratios of up to 25% were derived from lidar observations at 532 nm. Scattering phase functions retrieved from Sun photometer observations indicated particles of nonspherical shape. This shape caused unusually large particle extinction-to-backscatter ( lidar) ratios at 532 nm in the range from 50 to 80 sr. There were substantial deviations of the lidar ratio at 532 nm derived from both measurement methods. They are explained by the effect of particle shape. C1 Inst Troposparenforsch, D-04318 Leipzig, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Tech Univ Munich, Lehrstuhl Bioklimatol & Immiss Forsch, D-85354 Freising Weihenstephan, Germany. RP Inst Troposparenforsch, Permoserstr 15, D-04318 Leipzig, Germany. EM detlef@tropos.de; ina@tropos.de; ulla@tropos.de; albert@tropos.de; dietrich@tropos.de; dubovik@aeronet.gsfc.nasa.gov; eckhardt@forst.tu-muenchen.de; as@forst.tu-muenchen.de RI Stohl, Andreas/A-7535-2008; Dubovik, Oleg/A-8235-2009; Wandinger, Ulla/E-3348-2014; MUELLER, DETLEF/F-1010-2015; Eckhardt, Sabine/I-4001-2012 OI Stohl, Andreas/0000-0002-2524-5755; Dubovik, Oleg/0000-0003-3482-6460; MUELLER, DETLEF/0000-0002-0203-7654; Eckhardt, Sabine/0000-0001-6958-5375 NR 77 TC 72 Z9 73 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 17 PY 2003 VL 108 IS D12 AR 4345 DI 10.1029/2002JD002918 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 693XR UT WOS:000183744100002 ER PT J AU Wang, Y AF Wang, Y TI Wavelength selection with coupled surface plasmon waves SO APPLIED PHYSICS LETTERS LA English DT Article ID POLARITONS AB A process by which optical wavelengths can be selected by changing coupling distance of two surface plasmon waves is reported. When two surface plasmon waves are excited at metal/air/metal interfaces, coupling of the two surface plasmon waves will only allow a range of certain wavelengths to transmit. This wavelength selection depends on thickness of the air gap, and it does not have repeated passbands at harmonics. This phenomenon can be used to build broad-range tunable filters and spectrometers. Experiment showed the peak transmission wavelength could be continuously tuned from 400 to 900 nm with different voltages. (C) 2003 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wang, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 27 Z9 29 U1 0 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 JUN 16 PY 2003 VL 82 IS 24 BP 4385 EP 4387 DI 10.1063/1.1582357 PG 3 WC Physics, Applied SC Physics GA 688ZQ UT WOS:000183467500058 ER PT J AU Vancil, BK Wintucky, EG AF Vancil, BK Wintucky, EG TI Miniature reservoir cathode - an update SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Vacuum Electron Sources Conference CY JUL 15-19, 2002 CL SARATOV, RUSSIA DE cathode; reservoir cathode; thermionic; dispenser cathode AB We report on recent work to produce a small, low power, low cost reservoir cathode capable of long life (more than 100,000 h) at high loading (>5 A/cm(2)). Our objective is a highly manufacturable, commercial device costing less than US$ 30. Small highly loaded cathodes are needed, especially for millimeter traveling wave tubes, where focusing becomes difficult when area convergence ratios are too high. We currently have three models ranging from 0.060 to 0.125 in. diameter. (C) 2003 Elsevier Science B.V. All rights reserved. C1 FDE Inc, Beaverton, OR 97007 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Vancil, BK (reprint author), FDE Inc, 21070 SW Tile Flat Rd, Beaverton, OR 97007 USA. NR 5 TC 1 Z9 2 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD JUN 15 PY 2003 VL 215 IS 1-4 BP 18 EP 24 DI 10.1016/S0169-4332(03)00319-2 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 697VG UT WOS:000183963500003 ER PT J AU Maslov, AV Citrin, DS AF Maslov, AV Citrin, DS TI Quantum-well optical modulator at terahertz frequencies SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SIDE-BAND GENERATION; ABSORPTION; FIELD AB We predict that strong modulation of the optical properties of quantum wells at terahertz frequencies is possible. In this regime, the coherent nonlinear mixing of the optical and the terahertz-modulation fields leads to strong modification of the frequency dependence of the modulation depth. (C) 2003 American Institute of Physics. C1 Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA. RP NASA, Ames Res Ctr, MS229-1, Moffett Field, CA 94035 USA. EM maslov@ece.gatech.edu; david.citrin@ece.gatech.edu RI Maslov, Alexey/E-5158-2011 OI Maslov, Alexey/0000-0002-7835-2474 NR 15 TC 10 Z9 10 U1 1 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 15 PY 2003 VL 93 IS 12 BP 10131 EP 10133 DI 10.1063/1.1574590 PG 3 WC Physics, Applied SC Physics GA 685XD UT WOS:000183288900113 ER PT J AU Schwenke, DW AF Schwenke, DW TI New rovibrational kinetic energy operators using polyspherical coordinates for polyatomic molecules SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SPHERICAL POLAR PARAMETRIZATION; N-ATOM PROBLEM; VECTOR PARAMETRIZATION; TRIATOMIC-MOLECULES; QUANTUM-MECHANICS; HAMILTONIANS; REPRESENTATIONS; TERMS; MOMENTUM; SYSTEMS AB We illustrate how one can easily derive kinetic energy operators for polyatomic molecules using polyspherical coordinates with very general choices for z- axis embeddings and angles used to specify relative orientations of internal vectors. Computer algebra is not required. (C) 2003 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Schwenke, DW (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RI schwenke, david/I-3564-2013 NR 30 TC 12 Z9 13 U1 0 U2 5 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 15 PY 2003 VL 118 IS 23 BP 10431 EP 10438 DI 10.1063/1.1574013 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 683AJ UT WOS:000183124300009 ER PT J AU Lutz, RR Gannod, GC AF Lutz, RR Gannod, GC TI Analysis of a software product line architecture: an experience report SO JOURNAL OF SYSTEMS AND SOFTWARE LA English DT Article AB This paper describes experiences with the architectural specification and tool-assisted architectural analysis of a mission-critical, high-performance software product line. The approach used defines a "good" product line architecture in terms of those quality attributes required by the particular product line under development. Architectures are analyzed against several criteria by both manual and tool-supported methods. The approach described in this paper provides a structured analysis of an existing product line architecture using (1) architecture recovery and specification, (2) architecture evaluation, and (3) model checking of behavior to determine the,level of robustness and fault tolerance at the architectural level that are required for all systems in the product line. Results of an application to a software product line of spaceborne telescopes are used to explain the approach and describe lessons learned. Published by Elsevier Science Inc. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Iowa State Univ, Dept Comp Sci, Ames, IA 50011 USA. Arizona State Univ, Dept Comp Sci & Engn, Tempe, AZ 85287 USA. RP Lutz, RR (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM rlutz@cs.iastate.edu; gannod@asu.edu NR 21 TC 8 Z9 9 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0164-1212 EI 1873-1228 J9 J SYST SOFTWARE JI J. Syst. Softw. PD JUN 15 PY 2003 VL 66 IS 3 BP 253 EP 267 DI 10.1016/S0164-1212(02)00081-X PG 15 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 690UL UT WOS:000183568400007 ER PT J AU Tinto, M Shaddock, DA Sylvestre, J Armstrong, JW AF Tinto, M Shaddock, DA Sylvestre, J Armstrong, JW TI Implementation of time-delay interferometry for LISA SO PHYSICAL REVIEW D LA English DT Article ID FREQUENCY STABILIZATION; PHASE AB We discuss the baseline optical configuration for the Laser Interferometer Space Antenna (LISA) mission, in which the lasers are not free-running, but rather one of them is used as the main frequency reference generator (the master) and the remaining five as slaves, these being phase-locked to the master (the master-slave configuration). Under the condition that the frequency fluctuations due to the optical transponders can be made negligible with respect to the secondary LISA noise sources (mainly proof-mass and shot noises), we show that the entire space of interferometric combinations LISA can generate when operated with six independent lasers (the one-way method) can also be constructed with the master-slave system design. The corresponding hardware trade-off analysis for these two optical designs is presented, which indicates that the two sets of systems needed for implementing the one-way method, and the master-slave configuration, are essentially identical. Either operational mode could therefore be implemented without major implications on the hardware configuration. We then derive the required accuracies of armlength knowledge, time synchronization of the onboard clocks, sampling times and time-shifts needed for effectively implementing time-delay interferometry for LISA. We find that an armlength accuracy of about 16 meters, a synchronization accuracy of about 50 ns, and the time jitter due to a presently existing space qualified clock will allow the suppression of the frequency fluctuations of the lasers below to the level identified by the secondary noise sources. A new procedure for sampling the data in such a way to avoid the problem of having time shifts that are not integer multiples of the sampling time is also introduced, addressing one of the concerns about the implementation of time-delay interferometry. C1 CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. CALTECH, LIGO Lab, Pasadena, CA 91125 USA. RP Tinto, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Sylvestre, Julien/A-8610-2009; Shaddock, Daniel/A-7534-2011 OI Sylvestre, Julien/0000-0001-8136-4348; Shaddock, Daniel/0000-0002-6885-3494 NR 21 TC 37 Z9 38 U1 0 U2 4 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 JUN 15 PY 2003 VL 67 IS 12 AR 122003 DI 10.1103/PhysRevD.67.122003 PG 17 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 699UX UT WOS:000184075300006 ER PT J AU Kustas, WP Norman, JM Anderson, MC French, AN AF Kustas, WP Norman, JM Anderson, MC French, AN TI Estimating subpixel surface temperatures and energy fluxes from the vegetation index-radiometric temperature relationship SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE subpixel surface temperature; vegetation index; radiometric surface ID REMOTELY-SENSED DATA; REGIONAL-SCALE; SOIL; MODEL; EVAPOTRANSPIRATION; GRASSLAND; COVER AB Routine (i.e., daily to weekly) monitoring of surface energy fluxes, particularly evapotranspiration (ET), using satellite observations of radiometric surface temperature has not been feasible at high pixel resolution (i.e., similar to 10(1)-10(2) m) because of the low frequency in satellite coverage over the region of interest (i.e., approximately every 2 weeks). Cloud cover further reduces the number of useable observations of surface conditions resulting in high-resolution satellite imagery of a region typically being available once a month, which is not very useful for routine ET monitoring. Radiometric surface temperature observations at similar to 1- to 5-km pixel resolution are available multiple times per day from several weather satellites. However, this spatial resolution is too coarse for estimating ET from individual agricultural fields or for defining variations in ET due to land cover changes. Satellite data in the visible and near-infrared wavelengths, used for computing vegetation indices, are available at resolutions an order of magnitude smaller than in the thermal-infrared, and hence provide higher resolution information on vegetation cover conditions. A number of studies have exploited the relationship between vegetation indices and radiometric surface temperature for estimating model parameters used in computing spatially distributed fluxes and available moisture. In this paper, the vegetation index - radiometric surface temperature relationship is utilized in a disaggregation procedure for estimating subpixel variation in surface temperature with aircraft imagery collected over the US Southern Great Plains. The disaggregated surface temperatures estimated by this procedure are compared to actual observations at this subpixel resolution. In addition, a remote sensing-based energy balance model is used to compare output using actual versus estimated surface temperatures over a range of pixel resolutions. From these comparisons, the utility of the surface temperature disaggregation technique appears to be most useful for estimating subpixel surface temperatures at resolutions corresponding to length scales defining agricultural field boundaries across the landscape. Published by Elsevier Science Inc. C1 USDA ARS, BARC W, Hydrol & Remote Sensing Lab, Beltsville, MD 20705 USA. Univ Wisconsin, Dept Soil Sci, Madison, WI 53706 USA. NASA, Hydrol Sci Branch, Greenbelt, MD USA. RP Kustas, WP (reprint author), USDA ARS, BARC W, Hydrol & Remote Sensing Lab, Bldg 007,Roo 104, Beltsville, MD 20705 USA. RI Anderson, Martha/C-1720-2015 OI Anderson, Martha/0000-0003-0748-5525 NR 26 TC 190 Z9 215 U1 9 U2 40 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JUN 15 PY 2003 VL 85 IS 4 BP 429 EP 440 DI 10.1016/S0034-4257(03)00036-1 PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 681TN UT WOS:000183051600004 ER PT J AU Hu, H Liu, WT AF Hu, H Liu, WT TI Oceanic thermal and biological responses to Santa Ana winds SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB [1] Ocean surface wind vectors with improved spatial resolutions were derived from the National Aeronautics and Space Administration's (NASA's) Quick Scatterometer (QuikSCAT) satellite. They allow us to examine the details and extent of oceanic influence of a Santa Ana event - a strong offshore and downslope wind in southern California that may spread wide fires, damage properties, and endanger aviation. The oceanic thermal and biological responses to the surface wind jets were observed with other spaceborne sensors. It is found that surface wind jets reduce sea surface temperatures and increase biological productivities. Spacebased measurements demonstrate the inadequacy of current operational numerical weather prediction (NWP) models to accurately and consistently predict the characteristics of Santa Ana winds over the coastal ocean. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hu, H (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-323, Pasadena, CA 91109 USA. NR 12 TC 21 Z9 21 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 14 PY 2003 VL 30 IS 11 AR 1596 DI 10.1029/2003GL017208 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 691VM UT WOS:000183626700004 ER PT J AU Lemon, C Toffoletto, F Hesse, M Birn, J AF Lemon, C Toffoletto, F Hesse, M Birn, J TI Computing magnetospheric force equilibria SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE magnetosphere; force; equilibrium; MHD; magnetohydrodynamics; Tsyganenko ID MAGNETIC-FIELD; CONVECTION MODEL; MAGNETOTAIL; PLASMA; CONFIGURATIONS; DIMENSIONS; STABILITY; BOUNDARY; URANUS; LAYER AB [1] We describe a method to compute three-dimensional force equilibria in the Earth's magnetosphere. The method is embodied in a code called the MagnetoFriction code which solves a set of ideal magnetohydrodynamic (MHD) equations that are modified to include a frictional dissipation term in the momentum equation. The friction takes the form of a force which is directed against the fluid motion and is therefore an energy sink. This allows the system to settle into a minimum energy equilibrium. A nonuniform cartesian grid is used along with initial conditions supplied by empirical magnetic field and pressure models. These initial conditions do not, in general, satisfy the force balance condition (J) over right arrow x (B) over right arrow = del(p), and the code must iterate until approximate force balance is achieved. Pressure and magnetic field solutions are presented for several different configurations of the magnetosphere. C1 Rice Univ, Dept Phys & Astron, Rice Space Inst, Houston, TX 77251 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Los Alamos Natl Lab, Space Plasma Phys Grp, Los Alamos, NM 87545 USA. RP Lemon, C (reprint author), Rice Univ, Dept Phys & Astron, Rice Space Inst, POB 1892, Houston, TX 77251 USA. EM colby@rice.edu; toffo@rice.edu RI Hesse, Michael/D-2031-2012 NR 32 TC 21 Z9 21 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUN 13 PY 2003 VL 108 IS A6 AR 1237 DI 10.1029/2002JA009702 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 691YE UT WOS:000183632900004 ER PT J AU Tromp, TK Shia, RL Allen, M Eiler, JM Yung, YL AF Tromp, TK Shia, RL Allen, M Eiler, JM Yung, YL TI Potential environmental impact of a hydrogen economy on the stratosphere SO SCIENCE LA English DT Article ID MOLECULAR-HYDROGEN; TROPOSPHERE; H-2 AB The widespread use of hydrogen fuel cells could have hitherto unknown environmental impacts due to unintended emissions of molecular hydrogen, including an increase in the abundance of water vapor in the stratosphere ( plausibly by as much as similar to1 part per million by volume). This would cause stratospheric cooling, enhancement of the heterogeneous chemistry that destroys ozone, an increase in noctilucent clouds, and changes in tropospheric chemistry and atmosphere-biosphere interactions. C1 CALTECH, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yung, YL (reprint author), CALTECH, 1200 E Calif Blvd, Pasadena, CA 91125 USA. EM yly@gps.caltech.edu NR 22 TC 150 Z9 156 U1 3 U2 28 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 13 PY 2003 VL 300 IS 5626 BP 1740 EP 1742 DI 10.1126/science.1085169 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 688WF UT WOS:000183459700049 PM 12805546 ER PT J AU Diab, RD Raghunandan, A Thompson, AM Thouret, V AF Diab, RD Raghunandan, A Thompson, AM Thouret, V TI Classification of tropospheric ozone profiles over Johannesburg based on mozaic aircraft data SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID AIRBORNE PROGRAM; SOUTHERN AFRICA; SATELLITE; ATMOSPHERE; CLIMATOLOGY; SAFARI-92; EMISSIONS; EXCHANGE; TROPICS; EVENTS AB Each ozone profile is a unique response to the photochemical and dynamic processes operating in the troposphere and hence is critical to our understanding of processes and their relative contributions to the tropospheric ozone budget. Traditionally, mean profiles, together with some measure of variability, averaged by season or year at a particular location have been presented as a climatology. However, the mean profile is difficult to interpret because of the counteracting influences present in the micro-structure. On the other hand, case study analysis, whilst revealing, only applies to isolated conditions. In a search for pattern and order within ozone profiles, a classification based on a cluster analysis technique has been applied in this study. Ozone profiles are grouped according to the magnitude and altitude of ozone concentration. This technique has been tested with 56 ozone profiles at Johannesburg, South Africa, recorded by aircraft as part of the MOZAIC (Measurement of Ozone and Water Vapor aboard Airbus In-service Aircraft) program. Six distinct groups of ozone profiles have been identified and their characteristics described. The widely recognized spring maximum in tropospheric ozone is identified through the classification, but a new summertime mid-tropospheric enhancement due to the penetration of tropical air masses from continental regions in central Africa has been identified. Back trajectory modeling is used to provide evidence of the different origins of ozone enhancements in each of the classes. Continental areas over central Africa are shown to be responsible for the low to mid-tropospheric enhancement in spring and the mid-tropospheric peak in summer, whereas the winter low-tropospheric enhancement is attributed to local sources. The dominance of westerly winds through the troposphere associated with the passage of a mid-latitude cyclone gives rise to reduced ozone values. C1 Univ KwaZulu Natal, ZA-4001 Durban, South Africa. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CNRS, Toulouse, France. RP Diab, RD (reprint author), Univ KwaZulu Natal, ZA-4001 Durban, South Africa. EM diab@nu.ac.za RI Thompson, Anne /C-3649-2014; OI Thompson, Anne /0000-0002-7829-0920; Diab, Roseanne/0000-0002-3564-8320 NR 32 TC 18 Z9 19 U1 0 U2 2 PU COPERNICUS GESELLSCHAFT MBH PI GOTTINGEN PA BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY SN 1680-7316 EI 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JUN 12 PY 2003 VL 3 BP 713 EP 723 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 688VL UT WOS:000183457600001 ER PT J AU Fung, SF Benson, RF Carpenter, DL Green, JL Jayanti, V Galkin, IA Reinisch, BW AF Fung, SF Benson, RF Carpenter, DL Green, JL Jayanti, V Galkin, IA Reinisch, BW TI Guided echoes in the magnetosphere: Observations by Radio Plasma Imager on IMAGE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID DUCTED WHISTLER PROPAGATION; TOPSIDE-SOUNDER; FIELD; DENSITY; IRREGULARITIES; IONIZATION; SATELLITE; BUBBLES; RPI AB [1] Long-range, discrete, radio echo traces observed in the magnetosphere by the Radio Plasma Imager (RPI) on IMAGE have been interpreted as signals guided along geomagnetic field lines. During IMAGE traversals of the plasmapause and near-equatorial plasmasphere, multiple echo traces, attributed to signals reflected successively between conjugate hemispheres, are often observed. Single traces seen far beyond the plasmapause at high latitudes are attributed to guided echoes from the local hemisphere in the polar region. Here the field lines are either (1) open, (2) closed but too long to be observed within the instrument listening time or (3) closed but not able to maintain the signal-guiding conditions across the equator to the conjugate hemisphere. In this letter we present examples of guided echoes producing both the single and multiple reflection traces observed by RPI at altitudes of a few Earth radii and discuss possible guiding mechanisms. C1 NASA, Goddard Space Flight Ctr, Raytheon Informat Technol Serv, Greenbelt, MD 20771 USA. Stanford Univ, Space Telecommun & Radiosci Lab, Stanford, CA 94305 USA. NASA, Goddard Space Flight Ctr, Raytheon Sci Serv, Greenbelt, MD 20771 USA. Univ Massachusetts, Ctr Atmospher Res, Lowell, MA 01854 USA. RP Fung, SF (reprint author), NASA, Goddard Space Flight Ctr, Raytheon Informat Technol Serv, Greenbelt, MD 20771 USA. RI Fung, Shing/F-5647-2012 NR 23 TC 23 Z9 23 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 12 PY 2003 VL 30 IS 11 AR 1589 DI 10.1029/2002GL016531 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 691VG UT WOS:000183626100003 ER PT J AU Gutsev, GL Bauschlicher, CW AF Gutsev, GL Bauschlicher, CW TI Chemical bonding, electron affinity, and ionization energies of the homonuclear 3d metal dimers SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Review ID COLLISION-INDUCED DISSOCIATION; DENSITY-FUNCTIONAL THEORY; GENERALIZED-GRADIENT APPROXIMATION; ION PHOTOELECTRON-SPECTROSCOPY; SMALL IRON CLUSTERS; BAND SYSTEM; GAS-PHASE; TRANSITION-METALS; EXCHANGE-ENERGY; RESONANCE RAMAN AB Electronic and geometrical structures of the homonuclear 3d metal dimers M(2) (from Sc(2) to Zn(2)) as well as their M(2)(-) anions and M(2)(+) cations are computed using density functional theory with six generalized gradient approximations for the exchange-correlation potential. The neutral ground states are assigned as follows: Sc(2) ((5)Sigma(u)(-)), Ti(2) ((3)Delta(g)), V(2) ((3)Sigma(g)(-)), Cr(2) ((1)Sigma(+)), Mn(2) ((11)Pi(u)), Fe(2) ((7)Delta(u)), Co(2) ((5)Delta(g)), Ni(2) ((3)Sigma(g)(-)), Cu(2) ((1)Sigma(g)(+)), and Zn(2) ((1)Sigma(g)(+)). The anions are assigned as follows: Sc(2)(-) ((4)Sigma(g)(-)), Ti(2)(-) ((4)Delta(u)), V(2)(-) ((4)Sigma(+)), Mn(2)(-) ((10)Sigma(g)(-)), Fe(2)(-) ((8)Delta(g)), Co(2)(-) ((6)Delta(u)), Ni(2)(-) ((4)Sigma(u)(-)), and Cu(2)(-) ((2)Sigma(u)(+)) (Zn(2)(-) is unbound). The cations ground states are: Sc(2)(+) ((4)Sigma(g)(-)), Ti(2)(+) ((2)Delta(g)), V(2)(+) ((4)Sigma(g)(-)), Cr(2)(+) ((2)Sigma(+)), Mn(2)(+) ((10)Pi(u)), Fe(2)(+) ((8)Delta(u)), Co(2)(+) ((6)Gamma(g)), Ni(2)(+) ((4)Delta(g)), Cu(2)(+) ((2)Sigma(g)(+)), and Zn(2)(+) ((2)Sigma(u)(+)). A natural bond (NBO) analysis is used to obtain the chemical bonding patterns in the neutral and charged dimers. The results of the NBO analysis allow us to explain the changes in the ground-state spin multiplicities and spatial symmetries when moving along the neutral and ionic series. Consistent changes in the chemical bonding patterns of the neutral and charged dimers lend further support to our assignment of the ground states in the M(2)(-) and M(2)(+) series. Our calculated adiabatic electron affinities and ionization energies are in good agreement with experiment. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Gutsev, GL (reprint author), ELORET Corp, Mail Stop 230-3, Sunnyvale, CA 94087 USA. EM ggutsev@mail.arc.nasa.gov NR 108 TC 154 Z9 154 U1 4 U2 40 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 12 PY 2003 VL 107 IS 23 BP 4755 EP 4767 DI 10.1021/jp030146v PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 687YB UT WOS:000183403600025 ER PT J AU Fueglistaler, S Buss, S Luo, BP Wernli, H Flentje, H Hostetler, CA Poole, LR Carslaw, KS Peter, T AF Fueglistaler, S Buss, S Luo, BP Wernli, H Flentje, H Hostetler, CA Poole, LR Carslaw, KS Peter, T TI Detailed modeling of mountain wave PSCs SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID POLAR STRATOSPHERIC CLOUDS; LARGE HNO3-CONTAINING PARTICLES; NITRIC-ACID TRIHYDRATE; ARCTIC STRATOSPHERE; LIDAR OBSERVATIONS; REFRACTIVE-INDEXES; LIQUID PARTICLES; ANTARCTIC OZONE; MOTHER CLOUDS; TEMPERATURES AB Polar stratospheric clouds (PSCs) play a key role in polar ozone depletion. In the Arctic, PSCs can occur on the mesoscale due to orographically induced gravity waves. Here we present a detailed study of a mountain wave PSC event on 25-27 January 2000 over Scandinavia. The mountain wave PSCs were intensively observed by in-situ and remote-sensing techniques during the second phase of the SOLVE/THESEO-2000 Arctic campaign. We use these excellent data of PSC observations on 3 successive days to analyze the PSCs and to perform a detailed comparison with modeled clouds. We simulated the 3-dimensional PSC structure on all 3 days with a mesoscale numerical weather prediction (NWP) model and a microphysical box model (using best available nucleation rates for ice and nitric acid trihydrate particles). We show that the combined mesoscale/microphysical model is capable of reproducing the PSC measurements within the uncertainty of data interpretation with respect to spatial dimensions, temporal development and microphysical properties, without manipulating temperatures or using other tuning parameters. In contrast, microphysical modeling based upon coarser scale global NWP data, e. g. current ECMWF analysis data, cannot reproduce observations, in particular the occurrence of ice and nitric acid trihydrate clouds. Combined mesoscale/microphysical modeling may be used for detailed a posteriori PSC analysis and for future Arctic campaign flight and mission planning. The fact that remote sensing alone cannot further constrain model results due to uncertainities in the interpretation of measurements, underlines the need for synchronous in-situ PSC observations in campaigns. C1 ETH, Zurich, Switzerland. DLR Oberpfaffenhofen, D-82230 Wessling, Germany. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Univ Leeds, Sch Environm, Leeds, W Yorkshire, England. RP ETH, Zurich, Switzerland. EM stefanf@atmos.umnw.ethz.ch RI Carslaw, Ken/C-8514-2009; Fueglistaler, Stephan/I-5803-2013 OI Carslaw, Ken/0000-0002-6800-154X; NR 44 TC 35 Z9 35 U1 1 U2 5 PU COPERNICUS GESELLSCHAFT MBH PI GOTTINGEN PA BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY SN 1680-7316 EI 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JUN 11 PY 2003 VL 3 BP 697 EP 712 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 688VH UT WOS:000183457300002 ER PT J AU Chickos, JS Wentz, AE Hillesheim-Cox, D Zehe, MJ AF Chickos, JS Wentz, AE Hillesheim-Cox, D Zehe, MJ TI Measurement of the vaporization enthalpy of complex mixtures by correlation-gas chromatography. The vaporization enthalpy of RJ-4, a high-energy-density rocket fuel at T=298.15 K SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID 298.15 K; HYDROCARBONS; SUBLIMATION AB The use of correlation-gas chromatography to measure the vaporization enthalpy {Delta(l)(g)H(m)(298.15 K)} of complex mixtures is demonstrated using RJ-4, a high-energy-density rocket fuel, as a test sample. RJ-4 consists of a complex mixture of exo- and endo-dimethyltetrahydrodicyclo-pentadienes. A value of 55.3 +/- 0.9 kJ.mol(-1) has been obtained for the mixture. Correlation-gas chromatography is applicable in obtaining the vaporization enthalpy of any complex mixture of materials that will pass through a gas chromatograph and for which vaporization enthalpies of suitable standards are available. Once the temperature dependence of each component is established, the results can be used to determine the vaporization enthalpy at any composition. C1 Univ Missouri, Dept Chem, St Louis, MO 63121 USA. NASA, John Glenn Res Ctr, Cleveland, OH 44135 USA. RP Chickos, JS (reprint author), Univ Missouri, Dept Chem, St Louis, MO 63121 USA. NR 10 TC 9 Z9 9 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD JUN 11 PY 2003 VL 42 IS 12 BP 2874 EP 2877 DI 10.1021/ie020920l PG 4 WC Engineering, Chemical SC Engineering GA 687GX UT WOS:000183369200044 ER PT J AU Sabra, BM Hamann, F Jannuzi, BT George, IM AF Sabra, BM Hamann, F Jannuzi, BT George, IM TI The nature of the ultraviolet/X-ray absorber in PG 2302+029 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; quasars : absorption lines; quasars : individual (PG2302+029); X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; ABSORPTION-LINE QUASAR; LOW-REDSHIFT; KEY PROJECT; LUMINOSITY; SPECTRUM; PHL-5200; SYSTEMS; SAMPLE; WINDS AB We present Chandra X-ray observations of the radio-quiet QSO PG 2302+029. This quasar has a rare system of ultra-high-velocity (-56,000 km s(-1)) UV absorption lines that form in an outflow from the active nucleus. The Chandra data indicate that soft X-ray absorption is also present. We perform a joint UV and X-ray analysis, using photoionization calculations, to determine the nature of the absorbing gas. The UV and X-ray data sets were not obtained simultaneously. Nonetheless, our analysis suggests that the X-ray absorption occurs at high velocities in the same general region as the UV absorber. There are not enough constraints to rule out multizone models. In fact, the distinct broad and narrow UV line profiles clearly indicate that multiple zones are present. Our preferred estimates of the ionization and total column density in the X-ray absorber (log U = 1.6, N-H = 1022: 4 cm(-2)) overpredict the O VI lambdalambda1032, 1038 absorption unless the X-ray absorber is also out. owing at similar to56,000 km s(-1), but they overpredict the Ne VIII lambdalambda770, 780 absorption at all velocities. If we assume that the X-ray-absorbing gas is out. owing at the same velocity as the UV-absorbing wind and that the wind is radiatively accelerated, then the outflow must be launched at a radius of less than or equal to10(15) cm from the central continuum source. The smallness of this radius casts doubts on the assumption of radiative acceleration. C1 Univ Florida, Dept Astron, Gainesville, FL 32611 USA. Natl Opt Astron Observ, Tucson, AZ 85719 USA. Univ Maryland Baltimore Cty, Joint Ctr Astrophys, Dept Phys, Baltimore, MD 21250 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Ohio Univ, Dept Phys & Astron, Athens, OH 45701 USA. RP Sabra, BM (reprint author), Univ Florida, Dept Astron, Gainesville, FL 32611 USA. NR 36 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 2003 VL 590 IS 1 BP 66 EP 72 DI 10.1086/375006 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 685TE UT WOS:000183278700008 ER PT J AU Reiner, MJ Vourlidas, A St Cyr, OC Burkepile, JT Howard, RA Kaiser, ML Prestage, NP Bougeret, JL AF Reiner, MJ Vourlidas, A St Cyr, OC Burkepile, JT Howard, RA Kaiser, ML Prestage, NP Bougeret, JL TI Constraints on coronal mass ejection dynamics from simultaneous radio and white-light observations SO ASTROPHYSICAL JOURNAL LA English DT Article DE solar-terrestrial relations; Sun : activity; Sun : corona; Sun : flares; Sun : radio radiation ID INTERPLANETARY SHOCKS; SOLAR CORONA; LASCO OBSERVATIONS; ELECTRON-DENSITY; WIND SPACECRAFT; EMISSIONS; ORIGIN; BURST; EARTH; MHZ AB Simultaneous radio and white-light observations are used to deduce information on the dynamics of two coronal mass ejection (CME) events that occurred about 2 hr apart on 2001 January 20 and that were associated with eruptions from the same active region on the Sun. The analysis combines both space-based and ground-based data. The radio data were obtained from the WAVES experiment on the Wind spacecraft and from the Culgoora radiospectrograph in Australia. The white-light data were from the LASCO experiment on SOHO and from the Mk4 coronameter at the Mauna Loa Solar Observatory. For these CME events we demonstrate that the frequency drift rate of the type II radio emissions, generated by the shocks driven by the white-light CMEs, are consistent with the plane-of-sky height-time measurements, provided that the propagation direction of the CMEs and their associated radio sources was along a radial line from the Sun at a solar longitude of similar toE50degrees. These results imply that the "true'' CME speeds were estimated to be similar to1.4 times higher than the measured plane-of-sky speeds and that the CMEs originated from solar eruptions centered near E50degrees. This CME origin is consistent with the known active region and. are site associated with these two CME events. Furthermore, we argue that the type II radio emissions generated by these CMEs must have originated in enhanced density regions of the corona. We investigate whether the type II radiation could have originated in one or more dense coronal streamers, whose densities were estimated from the polarization brightness measurements made by LASCO at that time. Finally, we use these radio and white-light observations to speculate about the dynamics and scales involved in the interaction between these two CMEs. C1 Catholic Univ Amer, Ctr Solar Phys & Space Weather, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. George Mason Univ, Inst Computat Sci, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. Culgoora Solar Observ, IPS Radio & Space Sci, Narrabri, NSW 2390, Australia. Observ Paris, Dept Rech Spatiale, F-92195 Meudon, France. RP Reiner, MJ (reprint author), Catholic Univ Amer, Ctr Solar Phys & Space Weather, Washington, DC 20064 USA. RI Vourlidas, Angelos/C-8231-2009 OI Vourlidas, Angelos/0000-0002-8164-5948 NR 40 TC 55 Z9 57 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 2003 VL 590 IS 1 BP 533 EP 546 DI 10.1086/374917 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 685TE UT WOS:000183278700048 ER PT J AU Burlaga, LF Wang, C Richardson, JD Ness, NF AF Burlaga, LF Wang, C Richardson, JD Ness, NF TI Evolution of magnetic fields in corotating interaction regions from 1 to 95 AU: Order to chaos SO ASTROPHYSICAL JOURNAL LA English DT Article DE interplanetary medium; MHD; solar wind; Sun : magnetic fields ID MERGED INTERACTION REGIONS; LARGE HELIOCENTRIC DISTANCES; LARGE-SCALE FLUCTUATIONS; COSMIC-RAY MODULATION; SOLAR-WIND STRUCTURES; OUTER HELIOSPHERE; VOYAGER-2 OBSERVATIONS; PRESSURE WAVES; PICKUP IONS; PIONEER-10 AB We discuss the large-scale heliospheric magnetic field strength fluctuations as a function of distance from the Sun during the declining phase of a solar cycle, based on a one-dimensional, MHD, three-fluid model with observations made at 1 AU during 1995 as input. We consider daily averages of the magnetic field strength, B, as a function of time for a approximate to1 year interval. The model predicts that B(t) is quasi-periodic, and that the amplitudes of fluctuations in B relative to the yearly average of B ([B]) are relatively large between 5 and 20 AU ("the corotating merged interaction region zone,'' or CMIR zone). The model predicts that the fluctuations are aperiodic and that their amplitudes are relatively small between 30 and 95 AU ( the "wave interaction region zone ''). It predicts a transition between these two zones at approximate to25 AU. These results are consistent with a conceptual model proposed by Burlaga in 1983 for the declining phase of the solar cycle. In the CMIR zone, neighboring CMIRs merge in a sequence of events that defines a topological tree. The model predicts the following statistical properties of the fluctuations in B/[B] for the declining phase of a solar cycle in the CMIR zone: ( 1) the power spectrum of B/[B] has a prominent peak at 26 days and a secondary peak at 13 days; ( 2) the distribution of B/[B] has no simple form; and ( 3) the standard deviation (SD) of B/[B] is relatively large and has a maximum of 1.2 at 10 AU. In the wave interaction zone, ( 1) the spectrum has no significant peak, and the power level at 26 days is an order of magnitude smaller than in the CMIR zone; ( 2) the distribution of B/[B] is approximately lognormal; and ( 3) the SD(B/[B]) is nearly constant, approximate to0.48. The SD(B/[B]) versus R shows that the transition between the CMIR and the wave interaction zones is at approximate to25 +/- 5 AU. The results of the model are consistent with the Voyager 1 (V1) observations near 15 and 55 AU during 1983 and 1994, respectively. During the declining phase of solar cycle 23, in approximate to2003 - 2005, Voyager 2 (V2) will move from 69 to 76 AU while V1 moves from 87 to 95 AU. The model makes the following predictions for the properties of B between 65 and 95 AU: ( 1) B( t) will be aperiodic, with relatively low amplitude fluctuations similar to those observed at 55 AU; ( 2) the power spectra will resemble those observed near 55 AU, and there will be little radial variation in the power at the solar rotation period, 26 days; ( 3) the distribution of B will be approximately lognormal; (4) the SD(B) of the daily averages of B will be approximate to0.48 [B]; and (5) the tail of the distribution of B will be exponential. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Chinese Acad Sci, Lab Space Weather, Beijing, Peoples R China. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. RP Burlaga, LF (reprint author), NASA, Goddard Space Flight Ctr, Code 692, Greenbelt, MD 20771 USA. NR 36 TC 21 Z9 21 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 2003 VL 590 IS 1 BP 554 EP 566 DI 10.1086/374926 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 685TE UT WOS:000183278700050 ER PT J AU Michael, BP Nuth, JA Lilleleht, LU AF Michael, BP Nuth, JA Lilleleht, LU TI Zinc crystal growth in microgravity SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; dust, extinction; meteors, meteoroids; methods : laboratory ID NUCLEATION; PARTICLES; SPECTROSCOPY; METEORITE AB We report one of the first direct measurements of the efficiency of vapor - to - crystalline-solid growth in a microgravity environment aboard NASA's Reduced Gravity Research Facility. Zinc vapor is produced from a heater in a vacuum chamber containing argon gas. Vapor-phase nucleation is induced by cooling as the vapor expands away from the heat source, and its onset is easily detected visually by the appearance of a cloud of solid, crystalline zinc particles. The size distribution of these particles is monitored in situ by photon correlation spectroscopy. Samples were also extracted from the vapor for later analysis by scanning electron microscopy. The initial, rapid increase in the particle size distribution as a function of time is used to calculate the sticking efficiency for zinc atoms at growing crystal sites. Only a few of every 105 zinc atoms that collide with the grain surfaces are incorporated into the growing crystals. If the large (> 10 mum) graphite or SiC grains extracted from meteorites grow with comparable efficiency, then such materials could not have formed on timescales compatible with circumstellar outflows. However, these grains could have formed in equilibrium in stellar atmospheres prior to the initiation of the outflow. C1 Catholic Univ Amer, Dept Chem, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Astrochem Branch, Greenbelt, MD 20771 USA. Univ Virginia, Dept Chem Engn, Charlottesville, VA 22904 USA. RP Catholic Univ Amer, Dept Chem, Washington, DC 20064 USA. RI Nuth, Joseph/E-7085-2012; Michael, Patrick/N-6948-2013 OI Michael, Patrick/0000-0002-4742-4543 NR 21 TC 12 Z9 12 U1 1 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2003 VL 590 IS 1 BP 579 EP 585 DI 10.1086/374918 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 685TE UT WOS:000183278700053 ER PT J AU Lefloch, B Cernicharo, J Cabrit, S Noriega-Crespo, A Moro-Martin, A Cesarsky, D AF Lefloch, B Cernicharo, J Cabrit, S Noriega-Crespo, A Moro-Martin, A Cesarsky, D TI Warm molecular hydrogen and ionized neon in the HH 2 outflow SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : Herbig-Haro objects; ISM : individual (HH 1-2); ISM : jets and outflows; ISM : molecules; stars : formation ID HERBIG-HARO OBJECT-1; PROPER MOTIONS; C-TYPE; EMISSION; SHOCKS; EXCITATION; COMPLEX; CLOUDS; LINES; FLOW AB We report on spectro-imaging observations of the Herbig-Haro 2 outflow with the ISOCAM camera on board the Infrared Space Observatory. The [Ne II] 12.81 mum and [Ne III] 15.55 mum lines are detected only toward the jet working surface (HH 2H), consistent with the high excitation of this knot in the optical range, while H-2 pure rotational emission is found all over the shocked region HH 2. The low-energy transition S(2) traces warm gas (T similar to 400 K) peaked toward knots E and F and extended ejecta (T similar to 250-380 K) with masses of a few times 10(-3) M. in the high-velocity CO outflow extending between the powering source and HH 2. Such emission M, could arise from low-velocity C-type shocks (v similar or equal to 10-15 km s(-1)). The higher transitions S(3)-S(7) trace the emission of hot shocked gas (T = 1000-1400 K) from individual optical knots in the HH 2 region. The ortho -to-para (OTP) ratio exhibits large spatial variations between 1.2 (knot E) and 2.5 (knot H), well below its value at LTE. The emission of the S(3) - S(7) lines is well accounted for by planar C-shock models with a typical velocity V-s = 20-30 km s(-1) propagating into a medium of density n(t) = 10(4)-10(5) cm(-3) with an initial OTP ratio close to 1 in the preshock gas. In the leading edge of the jet, where the geometry of the emission allows a simple modeling, a good agreement is found with velocities derived from the optical proper motions measured in the ionized gas. C1 Observ Grenoble, Astrophys Lab, F-38041 Grenoble 9, France. CSIC, Inst Estructura Mat, E-28006 Madrid, Spain. Observ Paris, LERMA, CNRS, UMR 8112, F-75014 Paris, France. CALTECH, Jet Prop Lab, SIRTF SCi Ctr, Pasadena, CA 91125 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. RP Lefloch, B (reprint author), Observ Grenoble, Astrophys Lab, 414 Rue Piscine,BP 53, F-38041 Grenoble 9, France. NR 22 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 JUN 10 PY 2003 VL 590 IS 1 BP L41 EP L44 DI 10.1086/376673 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 685TF UT WOS:000183278800011 ER PT J AU Sandell, G Wright, M Forster, JR AF Sandell, G Wright, M Forster, JR TI NGC 7538S - A high-mass protostar with a massive rotating disk SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; ISM : clouds; stars : formation; stars : pre-main-sequence; submillimeter ID NGC-7538 REGION; STAR-FORMATION; YOUNG STARS; ABUNDANCES; OUTFLOWS; MASERS AB We report the detection of a massive rotating disk around the high-mass Class 0 candidate NGC 7538S. The disk is well resolved with the Berkeley-Illinois-Maryland Association array (theta(A) = 3."7) in the 3.4 mm continuum and in (HCN)-C-13 J = 1 --> 0. It is seen nearly edge-on and has a size of similar to30,000 AU. A young, powerful outflow perpendicular to the rotating disk is mapped in SiO J = 2 --> 1 and HCO+ J = 1 --> 0. The dynamical age of the outflow is less than or equal to10,000 yr. The velocity gradient seen in (HCN)-C-13 is consistent with Keplerian rotation. Assuming that the gas is gravitationally bound, the mass of the central object is similar to40 M.. The mass of the continuum "disk" is greater than or equal to100 M. and has a luminosity of similar to10(4) L. (HCN)-C-13 gives a mass of similar to400 M. for the rotating disk and of similar to1000 M. for the extended (20") envelope. Our observations confirm that this is an extremely massive protostar, in its earliest stages. C1 NASA, Ames Res Ctr, Univ Space Res Assoc, Moffett Field, CA 94035 USA. Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. RP Sandell, G (reprint author), NASA, Ames Res Ctr, Univ Space Res Assoc, MS 144-2, Moffett Field, CA 94035 USA. NR 18 TC 43 Z9 43 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2003 VL 590 IS 1 BP L45 EP L48 DI 10.1086/376612 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 685TF UT WOS:000183278800012 ER PT J AU Bogner, J Matthews, E AF Bogner, J Matthews, E TI Global methane emissions from landfills: New methodology and annual estimates 1980-1996 SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article DE landfill; landfill gas; methane emissions; methanotrophy; methanogenesis ID ATMOSPHERIC METHANE; COVER SOIL; TEMPORAL VARIATIONS; GROWTH-RATE; OXIDATION; WETLANDS AB Significant interannual variations in the growth rate of atmospheric CH4 justify the development of an improved methodology for landfill emissions, the largest anthropogenic source in many developed countries. A major problem is that reliable solid waste data often do not exist, especially for developing countries where emissions are increasing. Here we develop and apply a new proxy method to reconstruct historical estimates for annual CH4 emissions for the period 1980-1996. Using composited solid waste data from 1975-1995, we developed linear regressions for waste generation per capita based on energy consumption per capita, a surrogate which reflects population and affluence, the major determinants of solid waste generation rates. Using total population (developed countries) or urban population (developing countries), annual landfill CH4 emissions were estimated using a modified Intergovernmental Panel on Climate Change (IPCC) methodology. Methane recovery was modeled by fitting historic data to time-dependent linear relationships. Two scenarios for global emissions using the surrogate were compared to two scenarios using an IPCC standard methodology. Results from all four scenarios range from 16 to 57 Tg CH4 yr(-1,) a similar range as previous estimates. We support the use of the lower energy surrogate scenario (A) with annual emissions of 16-20 Tg CH4 yr(-1), both positive and negative annual variations, and commercial recovery > 15% by 1996. The surrogate provides a reasonable methodology for a large number of countries where data do not exist, a consistent methodology for both developed and developing countries, and a procedure which facilitates annual updates using readily available data. C1 Landfills Inc, Wheaton, IL 60187 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Illinois, Dept Earth & Environm Sci, Chicago, IL USA. RP Bogner, J (reprint author), Landfills Inc, 1144 N President St, Wheaton, IL 60187 USA. NR 82 TC 66 Z9 67 U1 1 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD JUN 10 PY 2003 VL 17 IS 2 AR 1065 DI 10.1029/2002GB001913 PG 18 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 691VT UT WOS:000183627200001 ER PT J AU DeFelice, TP Lloyd, D Meyer, DJ Baltzer, TT Piraino, P AF DeFelice, TP Lloyd, D Meyer, DJ Baltzer, TT Piraino, P TI Water vapour correction of the daily 1 km AVHRR global land dataset: part I - validation and use of the Water Vapour input field SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID DATA SET AB An atmospheric correction algorithm developed for the 1 km Advanced Very High Resolution Radiometer (AVHRR) global land dataset was modified to include a near real-time total column water vapour data input field to account for the natural variability of atmospheric water vapour. The real-time data input field used for this study is the Television and Infrared Observational Satellite (TIROS) Operational Vertical Sounder (TOVS) Pathfinder A global total column water vapour dataset. It was validated prior to its use in the AVHRR atmospheric correction process using two North American AVHRR scenes, namely 13 June and 28 November 1996. The validation results are consistent with those reported by others and entail a comparison between TOVS, radiosonde, experimental sounding, microwave radiometer, and data from a hand-held sunphotometer. The use of this data layer as input to the AVHRR atmospheric correction process is discussed. C1 EROS Data Ctr, ITSS, RAYTHEON, Dept Sci, Sioux Falls, SD 57198 USA. EROS Data Ctr, ITSS, RAYTHEON, Software Engn Dept, Sioux Falls, SD 57198 USA. NASA, SAIC, GSC, GSFC, Greenbelt, MD USA. RP DeFelice, TP (reprint author), EROS Data Ctr, ITSS, RAYTHEON, Dept Sci, Sioux Falls, SD 57198 USA. NR 17 TC 11 Z9 11 U1 0 U2 1 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 JUN 10 PY 2003 VL 24 IS 11 BP 2365 EP 2375 DI 10.1080/0143116021000053283 PG 11 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 676MP UT WOS:000182756100011 ER PT J AU Panzarella, CH Kassemi, M AF Panzarella, CH Kassemi, M TI On the validity of purely thermodynamic descriptions of two-phase cryogenic fluid storage SO JOURNAL OF FLUID MECHANICS LA English DT Article AB This paper presents a comprehensive analysis of the transport processes that control the self-pressurization of a cryogenic storage tank in normal gravity. A lumped thermodynamic model of the vapour region is coupled with the Navier-Stokes and energy equations governing heat, mass and momentum transport in the liquid. These equations are discretized using a Galerkin finite-element method with implicit time integration. Three case studies are considered based on three different heating configurations imposed on the tank wall: liquid heating, vapour heating and uniform heating. For each case, the pressure and temperature rise in the vapour and the flow and temperature distributions in the liquid are determined. Results are compared to a lumped thermodynamic model of the entire tank. It is shown that the final rate of pressure rise is about the same in each case and close to that predicted by thermodynamics even though the actual pressures are different because of varying degrees of thermal stratification. Finally, a subcooled liquid jet is used to mix the liquid and limit the pressure rise. Even so, there is still some thermal stratification in the liquid, and as a result the final vapour pressure depends on the particular heat distribution. C1 Ohio Aerosp Inst, Cleveland, OH 44142 USA. NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. RP Panzarella, CH (reprint author), Ohio Aerosp Inst, Cleveland, OH 44142 USA. NR 30 TC 21 Z9 24 U1 0 U2 4 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH ST, NEW YORK, NY 10011-4221 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JUN 10 PY 2003 VL 484 BP 41 EP 68 DI 10.1017/S0022112003004002 PG 28 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 696AX UT WOS:000183863500002 ER PT J AU Bozzolo, G Garces, JE Demarco, G AF Bozzolo, G Garces, JE Demarco, G TI Atomistic modeling of Au deposition on a Cu substrate SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 7th International Conference on Nanometer-Scale Science and Technology (NANO-7)/21st European Conference on Surface Science (ECOSS-21) CY JUN 24-28, 2002 CL MALMO, SWEDEN SP Swedish Res Council, Danish Nat Sci Res Council, Lund Univ, City Malmo, Nobel Fdn, Swedish Fdn Strateg Res, Swedish Agcy Innovat Syst, Reg Skane, Knowledge Fdn, NKT, USN Off Res, Japan Soc Promot Sci, IST Nanoelect Network PHANTOMS, Amer Vacuum Soc, Int Union Vacuum Sci, Tech & Applicat, Swedish Soc Vacuum Sci, Lund Univ, Nanometer Consortium DE adatoms; alloys; computer simulations; copper; gold; semi-empirical methods and model calculations; single crystal surfaces; surface structure, morphology, roughness, and topography ID SCANNING-TUNNELING-MICROSCOPY; SURFACE ALLOY; CU(100); LEED AB The Bozzolo-Ferrante-Smith method for alloys is applied to the study of Au growth on Cu(100) and Cu(110). Atom-by-atom analysis of the energy contributions of each atom in the system explain the observed features, highlighting the influence of the low coverage regime in the resulting surface alloy. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. Ctr Atom Bariloche, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina. RP Bozzolo, G (reprint author), NASA, Glenn Res Ctr, Mail Stop 23-2, Cleveland, OH 44135 USA. NR 18 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUN 10 PY 2003 VL 532 BP 41 EP 46 DI 10.1016/S0039-6028(03)00103-1 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 693FG UT WOS:000183705900009 ER PT J AU Dickey, JO Marcus, SL de Viron, O AF Dickey, JO Marcus, SL de Viron, O TI Coherent interannual and decadal variations in the atmosphere-ocean system SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SEA-SURFACE TEMPERATURES; 1986-87 EL-NINO; ANGULAR-MOMENTUM; SOUTHERN-OSCILLATION; VARIABILITY; PACIFIC; MODEL; CLIMATE; ENSO; PROPAGATION AB [1] We investigate the source of poleward propagating atmospheric zonal wind anomalies, originating at the equator and penetrating to high latitudes in both hemispheres in conjunction with ENSO [Dickey et al., 1992], and report the discovery of similar variability on decadal and longer timescales. Since atmospheric dissipation times are generally on the order of a month or less, we examine the ocean as a "memory'' source for these globally coherent anomalies. This hypothesis is substantiated by the observation of complementary oscillation in the sea surface temperature (SST) field; further, we detect a robust decadal variability (similar to10-12 yrs) in both the SST and contemporaneous atmospheric angular momentum (AAM) series. Analyzing GISST SST data beginning in 1902, we confirm this decadal mode and find signatures of longer (multidecadal) SST variability centered in the equatorial and North Pacific. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Observ Royal Belgique, B-1180 Brussels, Belgium. RP Dickey, JO (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI de Viron, Olivier/N-6647-2014 OI de Viron, Olivier/0000-0003-3112-9686 NR 35 TC 9 Z9 9 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 7 PY 2003 VL 30 IS 11 AR 1573 DI 10.1029/2002GL016763 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 690NB UT WOS:000183554300002 ER PT J AU Gopalswamy, N AF Gopalswamy, N TI Solar and geospace connections of energetic particle events SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CORONAL MASS EJECTIONS; PROTON EVENTS; RADIO-BURSTS; ORIGIN; SHOCKS AB [1] A Coordinated Data Analysis Workshop (CDAW) was conducted recently to study the solar and geospace connections of large solar energetic particle (SEP) events of solar cycle 23 (up to the end of 2001). This paper summarizes the properties these events, the scientific issues discussed, and some of the results obtained during the workshop. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gopalswamy, N (reprint author), NASA, Goddard Space Flight Ctr, Code 695, Greenbelt, MD 20771 USA. RI Gopalswamy, Nat/D-3659-2012 NR 15 TC 33 Z9 33 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 7 PY 2003 VL 30 IS 12 AR 8013 DI 10.1029/2003GL017277 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 690NC UT WOS:000183554400001 ER PT J AU Slinker, SP Fedder, JA Sibeck, DG Lyon, JG Frank, LA Mukai, T AF Slinker, SP Fedder, JA Sibeck, DG Lyon, JG Frank, LA Mukai, T TI Simulation of magnetopause oscillations observed January 9, 1996 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID INTERPLANETARY MAGNETIC-FIELD; KELVIN-HELMHOLTZ INSTABILITY; LATITUDE BOUNDARY-LAYER; GEOTAIL; VORTICES; MAGNETOSPHERE; MAGNETOTAIL; CONVECTION; INTERVAL; FLOW AB [1] On January 9, 1996, the Geotail spacecraft was near the dusk flank of the magnetopause at 18 MLT. From 0100-0300 UT several short excursions out of the magnetosphere were observed. This time interval was simulated with a 3D MHD magnetosphere model using measured solar wind and IMF data. The simulation produced oscillations resembling those recorded in terms of amplitude and frequency. We describe the details and global nature of the oscillations from the simulation and discuss the most likely source: the Kelvin-Helmholtz instability. C1 USN, Res Lab, Div Plasma Phys, Washington, DC 20375 USA. George Mason Univ, Fairfax, VA 22030 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Dartmouth Coll, Dept Phys, Hanover, NH 03755 USA. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. RP Slinker, SP (reprint author), USN, Res Lab, Div Plasma Phys, Code 6794, Washington, DC 20375 USA. EM david.sibeck@gsfc.nasa.gov; lyon@tinman.dartmouth.edu; frank@iowasp.physics.uiowa.edu; mukai@stp.isas.ac.jp RI Sibeck, David/D-4424-2012 NR 22 TC 14 Z9 15 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 JUN 6 PY 2003 VL 30 IS 11 AR 1569 DI 10.1029/2003GL017063 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 690NA UT WOS:000183554200004 ER PT J AU Ciszak, EM Korotchkina, LG Dominiak, PM Sidhu, S Patel, MS AF Ciszak, EM Korotchkina, LG Dominiak, PM Sidhu, S Patel, MS TI Structural basis for flip-flop action of thiamin pyrophosphate-dependent enzymes revealed by human pyruvate dehydrogenase SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID CRYSTAL-STRUCTURE; BENZOYLFORMATE DECARBOXYLASE; MULTIENZYME COMPLEXES; ANGSTROM RESOLUTION; ESCHERICHIA-COLI; DIPHOSPHATE; MOTIF; SITES; TRANSKETOLASE; INTERMEDIATE AB The derivative of vitamin B1, thiamin pyrophosphate, is a cofactor of enzymes performing catalysis in pathways of energy production. In alpha(2)beta(2)-heterotetrameric human pyruvate dehydrogenase, this cofactor is used to cleave the C-alpha-C(=O) bond of pyruvate followed by reductive acetyl transfer to lipoyl-dihydrolipoamide acetyltransferase. The dynamic nonequivalence of two, otherwise chemically equivalent, catalytic sites has not yet been understood. To understand the mechanism of action of this enzyme, we determined the crystal structure of the holo-form of human pyruvate dehydrogenase at 1.95-Angstrom resolution. We propose a model for the flip-flop action of this enzyme through a concerted similar to2-Angstrom shuttle-like motion of its heterodimers. Similarity of thiamin pyrophosphate binding in human pyruvate dehydrogenase with functionally related enzymes suggests that this newly defined shuttle-like motion of domains is common to the family of thiamin pyrophosphate-dependent enzymes. C1 NASA, Marshall Space Flight Ctr, Biol & Phys Space Res Lab, Huntsville, AL 35812 USA. Univ Space Res Assoc, Huntsville, AL 35812 USA. SUNY Buffalo, Dept Biochem, Sch Med & Biomed Sci, Buffalo, NY 14214 USA. RP Ciszak, EM (reprint author), NASA, Marshall Space Flight Ctr, Biol & Phys Space Res Lab, Huntsville, AL 35812 USA. FU NIDDK NIH HHS [DK20478] NR 33 TC 73 Z9 82 U1 3 U2 10 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 JUN 6 PY 2003 VL 278 IS 23 BP 21240 EP 21246 DI 10.1074/jbc.M300339200 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 684WY UT WOS:000183230500102 PM 12651851 ER PT J AU Beiersdorfer, P Boyce, KR Brown, GV Chen, H Kahn, SM Kelley, RL May, M Olson, RE Porter, FS Stahle, CK Tillotson, WA AF Beiersdorfer, P Boyce, KR Brown, GV Chen, H Kahn, SM Kelley, RL May, M Olson, RE Porter, FS Stahle, CK Tillotson, WA TI Laboratory simulation of charge exchange-produced x-ray emission from comets SO SCIENCE LA English DT Article ID IONS; COLLISIONS AB In laboratory experiments using the engineering spare microcalorimeter detector from the ASTRO-E satellite mission, we recorded the x-ray emission of highly charged ions of carbon, nitrogen, and oxygen, which simulates charge exchange reactions between heavy ions in the solar wind and neutral gases in cometary comae. The spectra are complex and do not readily match predictions. We developed a charge exchange emission model that successfully reproduces the soft x-ray spectrum of comet Linear C/1999 S4, observed with the Chandra X-ray Observatory. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Columbia Univ, Dept Phys, New York, NY 10027 USA. Univ Missouri, Dept Phys, Rolla, MO 65409 USA. RP Beiersdorfer, P (reprint author), Lawrence Livermore Natl Lab, 7000 East Ave,L-260, Livermore, CA 94550 USA. RI Porter, Frederick/D-3501-2012; Kelley, Richard/K-4474-2012 OI Porter, Frederick/0000-0002-6374-1119; NR 22 TC 116 Z9 117 U1 0 U2 12 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 6 PY 2003 VL 300 IS 5625 BP 1558 EP 1559 DI 10.1126/science.1084373 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 686QU UT WOS:000183333100051 PM 12791989 ER PT J AU Nemani, RR Keeling, CD Hashimoto, H Jolly, WM Piper, SC Tucker, CJ Myneni, RB Running, SW AF Nemani, RR Keeling, CD Hashimoto, H Jolly, WM Piper, SC Tucker, CJ Myneni, RB Running, SW TI Climate-driven increases in global terrestrial net primary production from 1982 to 1999 SO SCIENCE LA English DT Article ID VARIABILITY; RESOLUTION; BUDGET; INDEX AB Recent climatic changes have enhanced plant growth in northern mid-latitudes and high latitudes. However, a comprehensive analysis of the impact of global climatic changes on vegetation productivity has not before been expressed in the context of variable limiting factors to plant growth. We present a global investigation of vegetation responses to climatic changes by analyzing 18 years (1982 to 1999) of both climatic data and satellite observations of vegetation activity. Our results indicate that global changes in climate have eased several critical climatic constraints to plant growth, such that net primary production increased 6% (3.4 petagrams of carbon over 18 years) globally. The largest increase was in tropical ecosystems. Amazon rain forests accounted for 42% of the global increase in net primary production, owing mainly to decreased cloud cover and the resulting increase in solar radiation. C1 Univ Montana, Sch Forestry, Missoula, MT 59801 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92037 USA. Univ Tokyo, Grad Sch Agr & Life Sci, Bunkyo Ku, Tokyo 113, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Boston Univ, Dept Geog, Boston, MA 02215 USA. RP Nemani, RR (reprint author), Univ Montana, Sch Forestry, Missoula, MT 59801 USA. RI Mitchard, Edward/C-6346-2009; Myneni, Ranga/F-5129-2012; zhong, honglin/C-2633-2012; Noojipady, Praveen/B-2511-2010 NR 30 TC 1271 Z9 1470 U1 62 U2 470 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 6 PY 2003 VL 300 IS 5625 BP 1560 EP 1563 DI 10.1126/science.1082750 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 686QU UT WOS:000183333100052 PM 12791990 ER PT J AU Eddy, WM Allman, M AF Eddy, WM Allman, M TI A comparison of RED's byte and packet modes SO COMPUTER NETWORKS LA English DT Article DE active queue management; RED; congestion control ID INTERNET AB Routers making use of random early detection (RED) queueing take action to notify sources of growing congestion levels in the network before their resources are exhausted. The RED system hinges on two calculations: tracking the average queue size and the probability that an incoming packet is marked for congestion. These two calculations can be done in terms of the number of packets arriving at the router or in terms of the size of those packets (in bytes). Intuitively, these calculation methods offer different costs and benefits to traffic. This paper quantitatively assesses the impact of using the different queueing and marking methods on the performance of traffic traversing a RED gateway. We show that in some cases the calculation method makes a difference in the performance of the system, while in other cases the choice has little impact. We also provide a framework for rating the RED variants in particular situations in an attempt to aid in the choice of variant to use in a specific situations. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, Glenn Res Ctr, BBN Technol, Cleveland, OH 44135 USA. Ohio Univ, Athens, OH 45701 USA. RP Allman, M (reprint author), NASA, Glenn Res Ctr, BBN Technol, Cleveland, OH 44135 USA. EM weddy@irg.cs.ohiou.edu; mallman@bbn.com NR 20 TC 6 Z9 7 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1389-1286 EI 1872-7069 J9 COMPUT NETW JI Comput. Netw. PD JUN 5 PY 2003 VL 42 IS 2 BP 261 EP 280 DI 10.1016/S1389-1286(03)00195-6 PG 20 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 679CD UT WOS:000182902700007 ER PT J AU Neumann, GA Abshire, JB Aharonson, O Garvin, JB Sun, X Zuber, MT AF Neumann, GA Abshire, JB Aharonson, O Garvin, JB Sun, X Zuber, MT TI Mars Orbiter Laser Altimeter pulse width measurements and footprint-scale roughness SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SLOPES AB [1] The Mars Orbiter Laser Altimeter (MOLA) measured the pulse width and energy of altimetric laser returns during the course of two Mars years of operations. As secondary science objectives, MOLA obtains the footprint-scale roughness and the bidirectional reflectivity of Mars. MOLA underwent extensive preflight calibration and pulse measurements were monitored continuously in flight, but anomalous values of roughness have been inferred. A calibration of pulse widths using inflight data yields a slope-corrected roughness over similar to75-m-diameter footprints that may be used for quantitative geomorphic surface characterization, required, for example, for landing site selection. The recalibration uses a total least-squares estimation of pulse characteristics that generalizes the method of Abshire et al. [2000]. This method, utilizing the timing at voltage threshold crossings and the area between crossings, accounts for observation errors and shows that surface roughness as small as 1 m can be resolved. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. NASA Headquarters, Washington, DC 20546 USA. RP Neumann, GA (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Bldg 33, Greenbelt, MD 20771 USA. RI Sun, Xiaoli/B-5120-2013; Abshire, James/I-2800-2013; Neumann, Gregory/I-5591-2013 OI Neumann, Gregory/0000-0003-0644-9944 NR 11 TC 43 Z9 44 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 5 PY 2003 VL 30 IS 11 AR 1561 DI 10.1029/2003GL017048 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 690MY UT WOS:000183554000005 ER PT J AU Montesi, LGJ Zuber, MT AF Montesi, LGJ Zuber, MT TI Clues to the lithospheric structure of Mars from wrinkle ridge sets and localization instability SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Review DE wrinkle ridges; faulting; Mars; heat flow; strength envelope ID ORBITER LASER ALTIMETER; CENTRAL INDIAN BASIN; BLIND THRUST FAULTS; NORTHERN LOWLANDS; COASTAL GEOMORPHOLOGY; PELAGIC SEDIMENTATION; CRUSTAL THICKNESS; THERMAL EVOLUTION; VALLES-MARINERIS; THARSIS PLATEAU AB [1] Wrinkle ridges are a manifestation of horizontal shortening in planetary lithospheres, for which deformation is localized on faults that underlie individual ridges. In ridged plains of Mars, such as Solis Planum or Lunae Planum, wrinkle ridges are spaced similar to40 km apart, whereas in the Martian northern lowlands, where ridges are identified only in Mars Observed Laser Altimeter (MOLA) altimetric data, the ridge spacing is at least similar to80 km. We attribute ridge spacing to an instability of the lithosphere under horizontal compression. The localization instability, which results in periodically spaced faults [Montesi and Zuber, 2003a], links the difference of ridge spacing in the northern lowlands and in the highland ridged plains to the difference of crustal thickness via the depth of the brittle-ductile transition (BDT). In Solis and Lunae Plana, where the crust is 50 to 60 km thick, the crust may be ductile at depth, limiting faulting to the BDT of crustal rocks. In the lowlands, the crust is only about 30 km thick and may be brittle throughout. Thus the depth of faulting may be controlled by the BDT of mantle rocks, which is roughly a factor of two deeper than that of crustal rocks. The geotherm can be identical in both regions, at 12 +/- 3 K. km(-1), although differences of a few K. km(-1) can be accommodated within this model. The heat flux implied by this geotherm is similar to the heat produced by radiogenic decay 3 Gyr ago. Our analysis provides a rheological explanation for the difference in spacing between ridges in the highlands and the lowlands, in contrast to the suggestion of Head et al. [2002], who proposed that alternating lowlands ridges are buried by sediments. In addition, finite element models that use the lithospheric structure deduced from ridge spacing show that modest gradients of crustal thickness or heat flux across a ridged plains favor the formation of faults dipping toward high-elevation areas, as may be the case in Solis Planum [Golombek et al., 2001]. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. NASA, Terr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Montesi, LGJ (reprint author), Woods Hole Oceanog Inst, Dept Geol & Geophys, MS 22, Woods Hole, MA 02543 USA. RI Montesi, Laurent/C-5216-2009 OI Montesi, Laurent/0000-0002-3519-1412 NR 136 TC 48 Z9 48 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUN 5 PY 2003 VL 108 IS E6 AR 5048 DI 10.1029/2002JE001974 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 690PB UT WOS:000183556600001 ER PT J AU Abbas, MM Craven, PD Spann, JF Witherow, WK West, EA Gallagher, DL Adrian, ML Fishman, GJ Tankosic, D LeClair, A Sheldon, R Thomas, E AF Abbas, MM Craven, PD Spann, JF Witherow, WK West, EA Gallagher, DL Adrian, ML Fishman, GJ Tankosic, D LeClair, A Sheldon, R Thomas, E TI Radiation pressure measurements on micron-size individual dust grains SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE cosmic dust; interstellar dust; radiation pressure measurements; electrodynamic for radiation pressure; measurements; radiation pressure measurements on individual dust grains ID LIGHT-SCATTERING; ELECTRODYNAMIC BALANCE; OPTICAL LEVITATION; DIELECTRIC SPHERES; MIE SCATTERING; COSMIC DUST; PARTICLES; RESONANCES; FORCES AB [ ] Measurements of electromagnetic radiation pressure have been made on individual silica (SiO(2)) particles levitated in an electrodynamic balance. These measurements were made by inserting single charged particles of known diameter in the 0.2- to 6.82-mum range and irradiating them from above with laser radiation focused to beam widths of -175 400 mm at ambient pressures -10(-3) - 10(-4) torr. The downward displacement of the particle due to the radiation force is balanced by the electrostatic force indicated by the compensating dc potential applied to the balance electrodes, providing a direct measure of the radiation force on the levitated particle. Theoretical calculations of the radiation pressure with a least-squares fit to the measured data yield the radiation pressure efficiencies of the particles, and comparisons with Mie scattering theory calculations provide the imaginary part of the refractive index of SiO2 and the corresponding extinction and scattering efficiencies. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, NSSTC, Huntsville, AL 35805 USA. Auburn Univ, Dept Phys, Auburn, AL 36849 USA. RP Abbas, MM (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM mian.abbas@msfc.nasa.gov; andre.leclair@msfc.nasa.gov; rob.sheldon@mail.nsstc.nasa.gov; etjr@physics.auburn.edu NR 30 TC 13 Z9 13 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUN 5 PY 2003 VL 108 IS A6 AR 1229 DI 10.1029/2002JA009744 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 690PJ UT WOS:000183557200002 ER PT J AU Minihan, TP Lei, S Sun, G Palazzolo, A Kascak, AF Calvert, T AF Minihan, TP Lei, S Sun, G Palazzolo, A Kascak, AF Calvert, T TI Large motion tracking control for thrust magnetic bearings with fuzzy logic, sliding mode, and direct linearization SO JOURNAL OF SOUND AND VIBRATION LA English DT Article ID FEEDBACK; SYSTEMS AB Conventional use of magnetic bearings relies on a zero reference to keep the rotor centered in the radial and axial axes. This paper compares different control methods developed for the alternate control task of tracking an axial dynamic target. Controllers based on fuzzy logic, sliding mode, and direct linearization were designed to meet this task. Performance criteria, such as maximum axial displacement, minimum phase lag and I-2 R power losses were compared for each controller. The large motion, tracking problem for a rotor has utility in applications where dynamic seal clearances are required. This has a variety of potential applications in turbo-machinery, such as active stall control. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Texas A&M Univ, Dept Mech Engn, College Stn, TX 77843 USA. NASA Glenn, USA, Cleveland, OH USA. USN, Ctr Surface Warfare, Carderock Div, Philadelphia, PA USA. RP Minihan, TP (reprint author), Texas A&M Univ, Dept Mech Engn, MS 3123, College Stn, TX 77843 USA. NR 14 TC 13 Z9 14 U1 0 U2 4 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD JUN 5 PY 2003 VL 263 IS 3 BP 549 EP 567 AR PII S0022-460X(02)01066-0 DI 10.1016/S0022-460X(02)01066-0 PG 19 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 684QV UT WOS:000183218800005 ER PT J AU Henderson, JM Hoffman, RN Leidner, SM Atlas, R Brin, E Ardizzone, JV AF Henderson, JM Hoffman, RN Leidner, SM Atlas, R Brin, E Ardizzone, JV TI A comparison of a two-dimensional variational analysis method and a median filter for NSCAT ambiguity removal SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE variational data assimilation; NSCAT scatterometer; wind ambiguity removal; improving NWP representation of marine cyclones ID WEATHER ANALYSIS; DIRECT MINIMIZATION; SCATTEROMETER DATA; TROPICAL PACIFIC; WINDS; ASSIMILATION; OCEAN; MODEL; ALGORITHM; PRODUCTS AB [1] The ocean surface vector wind can be measured from space by scatterometers. For a set of measurements observed from several viewing directions and collocated in space and time, there will usually exist two, three, or four consistent wind vectors. These multiple wind solutions are known as ambiguities. Ambiguity removal procedures select one ambiguity at each location. We compare results of two different ambiguity removal algorithms, the operational median filter (MF) used by the Jet Propulsion Laboratory (JPL) and a two-dimensional variational analysis method (2d-VAR). We applied 2d-VAR to the entire NASA Scatterometer (NSCAT) mission, orbit by orbit, using European Centre for Medium-Range Weather Forecasts (ECMWF) 10-m wind analyses as background fields. We also applied 2d-VAR to a 51-day subset of the NSCAT mission using National Centers for Environmental Prediction (NCEP) 1000-hPa wind analyses as background fields. This second data set uses the same background fields as the MF data set. When both methods use the same NCEP background fields as a starting point for ambiguity removal, agreement is very good: Approximately only 3% of the wind vector cells (WVCs) have different ambiguity selections; however, most of the WVCs with changes occur in coherent patches. Since at least one of the selections is in error, this implies that errors due to ambiguity selection are not isolated, but are horizontally correlated. When we examine ambiguity selection differences at synoptic scales, we often find that the 2d-VAR selections are more meteorologically reasonable and more consistent with cloud imagery. C1 Atmospher & Environm Res Inc, Lexington, MA 02421 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Gen Sci Corp, Beltsville, MD USA. RP Henderson, JM (reprint author), Atmospher & Environm Res Inc, 131 Hartwell Ave, Lexington, MA 02421 USA. RI Atlas, Robert/A-5963-2011 OI Atlas, Robert/0000-0002-0706-3560 NR 28 TC 7 Z9 8 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 4 PY 2003 VL 108 IS C6 AR 3176 DI 10.1029/2002JC001307 PG 13 WC Oceanography SC Oceanography GA 690NV UT WOS:000183556000003 ER PT J AU Shields, DW Bering, EA Alaniz, A Mason, SEM Guo, W Arnoldy, RL Engebretson, MJ Hughes, WJ Murr, DL Lanzerotti, LJ Maclennan, CG AF Shields, DW Bering, EA Alaniz, A Mason, SEM Guo, W Arnoldy, RL Engebretson, MJ Hughes, WJ Murr, DL Lanzerotti, LJ Maclennan, CG TI Multistation studies of the simultaneous occurrence rate of Pc 3 micropulsations and magnetic impulsive events SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE Pc3; TCV; traveling current vortices; micropulsations; magnetic impulsive events; ULF ID TRAVELING CONVECTION VORTICES; KELVIN-HELMHOLTZ INSTABILITY; SOLAR-WIND VELOCITY; INTERPLANETARY MEDIUM; EARTHS MAGNETOPAUSE; MAGNETOMETER ARRAY; HIGH-LATITUDES; FLUX-TRANSFER; PULSATIONS; SIGNATURES AB [1] This study reports simultaneous observations of two different phenomena whose sources may be either near the magnetopause or in the solar wind: Pc 3 micropulsations and high-latitude magnetic impulsive events (MIEs), whose best studied subset comprises traveling current vortices (TCVs). Isolated Pc 3 emissions that occurred simultaneously with MIE or TCV events and appeared to have the same horizontal speed as the TCVs have been reported. This observation suggests that these events were on the same geomagnetic field lines and may share a common source. The current study reports a search of existing databases for simultaneous Pc 3-MIE observations. The databases that were searched are the South Pole search coil magnetometer data during 1985-1986 and the Magnetometer Array for Cusp and Cleft Studies (MACCS) database from 1992 to 1993. The rate of occurrence of joint Pc 3 bursts and high-latitude impulsive events has been consistently found to be similar to70-90%, depending on the database. The rate of coincidence is so high that it suggests that search algorithms based on ground-based data that seek "clean'' MIE signals may be omitting some events owing to the presence of large-amplitude ULF emissions. A reverse search for candidate MIEs occurring during dayside Pc 3 bursts doubled the number of candidate MIEs in the database. The final results show that 91% of all MIEs were accompanied by Pc 3 emissions, and 43% of all 10-30 min bursts or banded enhancements in Pc 3 emission were accompanied by an MIE. A statistical analysis confirms that the correlation rates are statistically significant. The observed dependence of the properties of the MIE-concurrent Pc 3s on the solar wind and interplanetary magnetic field is consistent with previous studies of Pc 3s of solar wind origin. C1 Univ Houston, Dept Phys, Houston, TX 79204 USA. Univ Houston, Dept Elect & Comp Engn, Houston, TX USA. NASA, Adv Space Prop Lab, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ New Hampshire, Dept Phys, Durham, NH 03824 USA. Univ New Hampshire, Inst Earth Oceans & Space, Durham, NH 03824 USA. Augsburg Coll, Dept Phys, Minneapolis, MN 55454 USA. Boston Univ, Dept Astron, Boston, MA 02215 USA. Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. Bell Labs Lucent Technol, Murray Hill, NJ 07974 USA. RP Shields, DW (reprint author), Univ Houston, Dept Phys, 4800 Calhoun Blvd, Houston, TX 79204 USA. NR 45 TC 7 Z9 8 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 4 PY 2003 VL 108 IS A6 AR 1225 DI 10.1029/2002JA009397 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 690PH UT WOS:000183530500003 ER PT J AU Chylek, P Henderson, B Mishchenko, M AF Chylek, P Henderson, B Mishchenko, M TI Satellite based retrieval of aerosol optical thickness: The effect of sun and satellite geometry SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TROPOSPHERIC AEROSOL; CLIMATE; TARFOX; LAND; ATSR-2; OCEAN; POLARIZATION; ATMOSPHERES; REFLECTANCE; SCATTERING AB [1] The DOE research satellite instrument, the Multispectral Thermal Imager (MTI), has several spectral bands in the visible and near infrared part of the spectrum that can be used for AOD (Aerosol Optical Depth) retrieval. Small pixel size (5 m x 5 m in the visible and 20 m x 20 m in the infrared) eliminates most sub-pixel size cloud problems. We analyze 18 pairs of images, taken close to nadir and back along the track at a viewing angle around 60degrees, and compare results of a single view AOD retrieval algorithm with the AERONET measurements. We find that the single view AOD retrieval algorithm is more accurate at smaller scattering angles (at off-nadir view). The root mean square (RMS) error of the MTI AOD single view retrieval in this region is around 0.03 compared to 0.11 for larger scattering angles at near-nadir view. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Dalhousie Univ, Dept Phys & Atmospher Sci, Halifax, NS, Canada. New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. RP Los Alamos Natl Lab, Mail Stop D436, Los Alamos, NM 87545 USA. EM chylek@lanl.gov; henders@lanl.gov; crmim@giss.nasa.gov RI Mishchenko, Michael/D-4426-2012 NR 29 TC 13 Z9 13 U1 0 U2 2 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 3 PY 2003 VL 30 IS 11 AR 1553 DI 10.1029/2003GL016917 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 690MW UT WOS:000183553800004 ER PT J AU Shetter, RE Junkermann, W Swartz, WH Frost, GJ Crawford, JH Lefer, BL Barrick, JD Hall, SR Hofzumahaus, A Bais, A Calvert, JG Cantrell, CA Madronich, S Muller, M Kraus, A Monks, PS Edwards, GD McKenzie, R Johnston, P Schmitt, R Griffioen, E Krol, M Kylling, A Dickerson, RR Lloyd, SA Martin, T Gardiner, B Mayer, B Pfister, G Roth, EP Koepke, P Ruggaber, A Schwander, H van Weele, M AF Shetter, RE Junkermann, W Swartz, WH Frost, GJ Crawford, JH Lefer, BL Barrick, JD Hall, SR Hofzumahaus, A Bais, A Calvert, JG Cantrell, CA Madronich, S Muller, M Kraus, A Monks, PS Edwards, GD McKenzie, R Johnston, P Schmitt, R Griffioen, E Krol, M Kylling, A Dickerson, RR Lloyd, SA Martin, T Gardiner, B Mayer, B Pfister, G Roth, EP Koepke, P Ruggaber, A Schwander, H van Weele, M TI Photolysis frequency of NO2: Measurement and modeling during the International Photolysis Frequency Measurement and Modeling Intercomparison (IPMMI) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE photolysis; NO2 (nitrogen dioxide); radiative transfer; intercomparison ID ACTINIC FLUX SPECTRORADIOMETRY; ABSORPTION CROSS-SECTIONS; OBSERVATORY PHOTOCHEMISTRY EXPERIMENT; RATE COEFFICIENT; ATLANTIC-OCEAN; TEMPERATURE; ATMOSPHERE; PHOTODISSOCIATION; RADIATION; OZONE AB [1] The photolysis frequency of NO2, j(NO2), was determined by various instrumental techniques and calculated using a number of radiative transfer models for 4 days in June 1998 at the International Photolysis Frequency Measurement and Modeling Intercomparison (IPMMI) in Boulder, Colorado. Experimental techniques included filter radiometry, spectroradiometry, and chemical actinometry. Eight research groups participated using 14 different instruments to determine j( NO2). The blind intercomparison experimental results were submitted to the independent experimental referee and have been compared. Also submitted to the modeling referee were the results of NO2 photolysis frequency calculations for the same time period made by 13 groups who used 15 different radiative transfer models. These model results have been compared with each other and also with the experimental results. The model calculation of clear-sky j(NO2) values can yield accurate results, but the accuracy depends heavily on the accuracy of the molecular parameters used in these calculations. The instrumental measurements of j(NO2) agree to within the uncertainty of the individual instruments and indicate the stated uncertainties in the instruments or the uncertainties of the molecular parameters may be overestimated. This agreement improves somewhat with the use of more recent NO2 cross-section data reported in the literature. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80303 USA. Forschungszentrum Karlsruhe, Inst Meteorol & Klimaforsch, D-82467 Garmisch Partenkirchen, Germany. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Forschungszentrum Julich, Geosphare Inst Troposphare 2, Inst Chem & Dynam, D-52425 Julich, Germany. Aristotle Univ Thessaloniki, Lab Atmospher Phys, GR-54006 Thessaloniki, Greece. Univ Leicester, Leicester LE1 7RH, Leics, England. Natl Inst Water & Atmospher Res, Lauder 50061, New Zealand. Meteorol Consult GmbH, D-61479 Glashutten, Germany. Meteorol Serv Canada, Toronto, ON M3H 5T4, Canada. Inst Marine & Atmospher Res, NL-3508 TA Utrecht, Netherlands. Norwegian Inst Air Res, N-2027 Kjeller, Norway. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. Karl Franzens Univ Graz, Inst Geophys Astrophys & Meteorol, Graz, Austria. British Antarctic Survey, Cambridge CB3 0ET, England. Forschungszentrum Julich, Geosphare Inst Stratosphare 1, Inst Chem & Dynam, D-52425 Julich, Germany. Univ Munich, Inst Meteorol, D-80333 Munich, Germany. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. RP Shetter, RE (reprint author), Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80303 USA. EM junkermann@ifu.fhg.de; bill.swartz@jhuapl.edu; gfrost@al.noaa.gov; j.h.crawford@larc.nasa.gov; pfister@ucar.edu; halls@ucar.edu; sasha@acd.ucar.edu; abais@auth.gr; calvert@acd.ucar.edu; cantrell@ncar.ucar.edu; p.s.monks@le.ac.uk; r.mckenzie@niwa.co.nz; paul.c.johnston@asu.edu; erik@nimbus.yorku.ca; M.Krol@phys.uu.nl; arve.kylling@nilu.no; russ@atmos.umd.edu; Steven.Lloyd@jhuap1.edu; timothy.martin@gmx.de; brian.gardiner@bas.ac.uk; bernhard.mayer@dlr.de; pfister@ucar.edu; ggp@bimgs5.kfunigraz.ac.at; ruggaber@lrz.uni-muenchen.de; weelevm@knmi.nl RI Lefer, Barry/B-5417-2012; Pfister, Gabriele/A-9349-2008; Mayer, Bernhard/B-3397-2011; Krol, Maarten/B-3597-2010; Bais, Alkiviadis/D-2230-2009; Swartz, William/A-1965-2010; Hofzumahaus, Andreas/I-9420-2012; Junkermann, Wolfgang/A-7416-2013; Frost, Gregory/I-1958-2013; Crawford, James/L-6632-2013; Krol, Maarten/E-3414-2013; Garmisch-Pa, Ifu/H-9902-2014; Madronich, Sasha/D-3284-2015; Dickerson, Russell/F-2857-2010; Monks, Paul/H-6468-2016; Kylling, Arve/B-1137-2017 OI Lefer, Barry/0000-0001-9520-5495; Mayer, Bernhard/0000-0002-3358-0190; Bais, Alkiviadis/0000-0003-3899-2001; Swartz, William/0000-0002-9172-7189; Hofzumahaus, Andreas/0000-0003-2876-0880; Crawford, James/0000-0002-6982-0934; Madronich, Sasha/0000-0003-0983-1313; Dickerson, Russell/0000-0003-0206-3083; Monks, Paul/0000-0001-9984-4390; Kylling, Arve/0000-0003-1584-5033 NR 51 TC 33 Z9 34 U1 1 U2 13 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 3 PY 2003 VL 108 IS D16 AR 8544 DI 10.1029/2002JD002932 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 690NQ UT WOS:000183555600001 ER PT J AU Zhang, JL Thomas, DR Rothrock, DA Lindsay, RW Yu, Y Kwok, R AF Zhang, JL Thomas, DR Rothrock, DA Lindsay, RW Yu, Y Kwok, R TI Assimilation of ice motion observations and comparisons with submarine ice thickness data SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE sea ice modeling; data assimilation; optimal interpolation ID ARCTIC SEA-ICE; FRAM STRAIT; MODEL; OCEAN; DYNAMICS; DEFORMATION; OSCILLATION; BALANCE; IMAGERY; CLIMATE AB [1] Aided by submarine observations of ice thickness for model evaluation, we investigate the effects of assimilating buoy motion data and satellite SSM/I (85 Ghz) ice motion data on simulation of Arctic sea ice. The sea-ice model is a thickness and enthalpy distribution model and is coupled to an ocean model. Ice motion data are assimilated by means of optimal interpolation. Assimilating motion data, particularly from drifting buoys, significantly improves the modeled ice motion, reducing the error to 0.04 m s(-1) from 0.07 m s(-1) and increasing the correlation with observations to 0.90 from 0.66. Without data assimilation, the modeled ice moves too slowly with excessive stoppage. Assimilation leads to more robust ice motion with substantially reduced stoppage, which in turn leads to strengthened ice outflow at Fram Strait and enhanced ice deformation everywhere. Enhanced deformation doubles the production of ridged ice to an Arctic Ocean average of 0.77 m yr(-1), and raises the amount of ridged ice to half the total ice volume per unit area of 2.58 m. Assimilation also significantly alters the spatial distribution of ice mass and brings the modeled ice thickness into better agreement with the thickness observed in four recent submarine cruises, reducing the error to 0.66 m from 0.76 m, and increasing the correlation with observations to 0.65 from 0.45. Buoy data are most effective in reducing model errors because of their small measurement error. SSM/I data, because of their more complete spatial coverage, are helpful in regions with few buoys, particularly in coastal areas. Assimilating both SSM/I and buoy data combines their individual advantages and brings about the best overall model performance in simulating both ice motion and ice thickness. C1 Univ Washington, Coll Ocean & Fishery Sci, Appl Phys Lab, Polar Sci Ctr, Seattle, WA 98105 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zhang, JL (reprint author), Univ Washington, Coll Ocean & Fishery Sci, Appl Phys Lab, Polar Sci Ctr, Seattle, WA 98105 USA. RI Kwok, Ron/A-9762-2008; Lindsay, Ron/S-9083-2016 OI Kwok, Ron/0000-0003-4051-5896; NR 42 TC 29 Z9 29 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 3 PY 2003 VL 108 IS C6 AR 3170 DI 10.1029/2001JC001041 PG 18 WC Oceanography SC Oceanography GA 690NT UT WOS:000183555800001 ER PT J AU Koblinsky, CJ Hildebrand, P LeVine, D Pellerano, F Chao, Y Wilson, W Yueh, S Lagerloef, G AF Koblinsky, CJ Hildebrand, P LeVine, D Pellerano, F Chao, Y Wilson, W Yueh, S Lagerloef, G TI Sea surface salinity from space: Science goals and measurement approach SO RADIO SCIENCE LA English DT Article DE ocean salinity; sea surface salinity; passive microwave; microwave radiometers ID PACIFIC WARM POOL; OCEAN SALINITY; NORTH-ATLANTIC; L-BAND; TEMPERATURE AB [1] Aquarius is a NASA/Earth System Science Pathfinder (ESSP) mission that proposes to make the first-ever global measurements of sea surface salinity. These measurements will enable improved understanding of oceanic thermohaline circulation and of the changes in oceanic circulation that are related to seasonal to interannual climate variability. Aquarius science goals also address tropical ocean-climate feedbacks and freshwater budget components of the coupled ocean-atmosphere system. These oceanographic science requirements for Aquarius dictate measurements of global sea surface salinity that are accurate to 0.2-0.3 psu, as averaged monthly and over 100-200 km areas. Key aspects of the Aquarius salinity mission design include the instrument with its high-stability L-band radiometers, the precise calibration of the measurements, and the salinity retrieval algorithm. The Aquarius mission will meet the science needs by providing complete global coverage of ocean surface salinity, with an 8 day cycle of observations using a three beam, L-band radiometer/scatterometer flying in a 6 am/6 pm polar orbit. This conceptual design has been verified using observations from aircraft flight instruments. The radiometer design for the instrument and the needed precise calibration is based on proven, temperature-stabilized radiometer designs with internal references, plus vicarious calibration approaches developed in the course of previous space missions. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Earth & Space Res Inc, Seattle, WA USA. RP Koblinsky, CJ (reprint author), NASA, Goddard Space Flight Ctr, Code 975, Greenbelt, MD 20771 USA. NR 25 TC 43 Z9 45 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JUN 3 PY 2003 VL 38 IS 4 AR 8064 DI 10.1029/2001RS002584 PG 8 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 690PU UT WOS:000183558100001 ER PT J AU Roeber, D Achari, A Takai, T Okumura, Y Scott, DL AF Roeber, D Achari, A Takai, T Okumura, Y Scott, DL TI Crystallization and preliminary X-ray analysis of Der f 2, a potent allergen derived from the house dust mite (Dermatophagoides farinae) SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID HISTAMINE-RELEASING ACTIVITY; MOLECULAR REPLACEMENT; IGE-BINDING; DER-P-2; DER-F-2; MUTATION; F-2 AB Although a number of allergens have been identified and isolated, the underlying molecular basis for the potent immune response is poorly understood. House dust mites (Dermatophagoides sp.) are ubiquitous contributors to atopy in developed countries. The rhinitis, dermatitis and asthma associated with allergic reactions to these arthropods are frequently caused by relatively small (125-129 amino acids) mite proteins of unknown biological function. Der f 2, a major allergen from the mite D. farinae, has been recombinantly expressed, characterized and crystallized. The crystals belong to the tetragonal space group I4(1)22, with unit-cell parameters a = b = 95.2, c = 103.3 Angstrom. An essentially complete ( 97.2%) data set has been collected to 2.4 Angstrom at a synchrotron source. Attempts to solve the crystal structure of Der f 2 by molecular replacement using the NMR coordinates for either Der f 2 or Der p 2 ( the homologous protein from D. pteronyssinus) failed, but preliminary searches using the crystalline Der p 2 atomic coordinates appear to be promising. C1 Harvard Univ, Sch Med, Massachusetts Gen Hosp, Dept Med, Charlestown, MA 02129 USA. NASA, Struct Biol Lab, MSFC, Huntsville, AL 35812 USA. Asahi Brewery Co Ltd, Biosci Res & Dev Lab, Moriya, Ibaraki, Japan. Harvard Univ, Sch Med, Massachusetts Gen Hosp, Struct Biol Ctr, Charlestown, MA 02129 USA. RP Scott, DL (reprint author), Harvard Univ, Sch Med, Massachusetts Gen Hosp, Dept Med, 149 13th St, Charlestown, MA 02129 USA. RI Takai, Toshiro/K-5690-2013 NR 19 TC 4 Z9 4 U1 0 U2 1 PU BLACKWELL MUNKSGAARD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD JUN PY 2003 VL 59 BP 1046 EP 1048 DI 10.1107/S0907444903004438 PN 6 PG 3 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 681PC UT WOS:000183043700013 PM 12777769 ER PT J AU Wrotek, S Dybko, K Morawski, A Makosa, A Wosinski, T Figielski, T Tkaczyk, Z Lusakowska, E Story, T Sipatov, AY Szczerbakow, A Grasza, K Wrobel, J Palosz, W AF Wrotek, S Dybko, K Morawski, A Makosa, A Wosinski, T Figielski, T Tkaczyk, Z Lusakowska, E Story, T Sipatov, AY Szczerbakow, A Grasza, K Wrobel, J Palosz, W TI Vertical electron transport through PbS-EuS structures SO ACTA PHYSICA POLONICA A LA English DT Article; Proceedings Paper CT 32nd International School on the Physics of Semiconducting Compounds CY MAY 30-JUN 06, 2003 CL JASZOWIEC, POLAND ID MAGNETIC SEMICONDUCTORS; MULTILAYERS; GROWTH AB Temperature dependence of current-voltage I-V characteristics and resistivity is studied in ferromagnetic PbS-EuS semiconductor tunnel structures grown on n-PbS (100) substrates. For the structures with a single (2-4 nm thick) ferromagnetic EuS electron barrier we observe strongly non-linear I-V characteristics with an effective tunneling barrier height of 0.3-0.7 eV. The experimentally observed non-monotonic temperature dependence of the (normal to the plane of the structure) electrical resistance of these structures is discussed in terms of the electron tunneling mechanism taking into account the temperature dependent shift of the band offsets at the EuS-PbS heterointerface as well as the exchange splitting of the electronic states at the bottom of the conduction band of EuS. C1 Polish Acad Sci, Inst Phys, PL-02668 Warsaw, Poland. Natl Tech Univ KPI, UA-61002 Kharkov, Ukraine. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Wrotek, S (reprint author), Polish Acad Sci, Inst Phys, Al Lotnikow 32-46, PL-02668 Warsaw, Poland. RI Wosinski, Tadeusz/A-2020-2008; Wrobel, Jerzy/G-8042-2014; Dybko, Krzysztof/K-9400-2016; OI Dybko, Krzysztof/0000-0002-6795-1252; Sipatov, Alexander/0000-0002-2693-2135 NR 14 TC 1 Z9 1 U1 0 U2 0 PU POLISH ACAD SCIENCES INST PHYSICS PI WARSAW PA AL LOTNIKOW 32-46, 02-668 WARSAW, POLAND SN 0587-4246 J9 ACTA PHYS POL A JI Acta Phys. Pol. A PD JUN PY 2003 VL 103 IS 6 BP 629 EP 635 PG 7 WC Physics, Multidisciplinary SC Physics GA 709WH UT WOS:000184649200018 ER PT J AU Bushnell, DM AF Bushnell, DM TI The 'air side' of future warfare - military aeronautics SO AERONAUTICAL JOURNAL LA English DT Article AB The ongoing revolutions in information, biological, energetics and nano technologies are changing the nature and equipment of warfare. This is particularly true in military aeronautics. In the nearer term aircraft are becoming increasingly 'uninhabited' (UCAVs, UAVs etc.) enabled by the IT revolution, with multitudinous accompanying benefits in terms of affordability, survivability, redefinition of 'risk' and lethality. THE issue for such aircraft is enhanced persistence and increased range within the context of the overall system metrics. In the longer term the increasingly capable worldwide 'sensor web' will place at risk all air vehicles, in or out of theatre and whether or not they are 'stealthy'. This, combined with advanced conventional weapons, high energy density material powered EMP (electro-magnetic-pulse) weapons and affordable swarms of 'brilliant' munitions will probably require yet another re-definition of military aeronautics, perhaps as survivable (hardened) hypersonic, global range, boost-glide devices. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Bushnell, DM (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 0 TC 1 Z9 1 U1 1 U2 3 PU ROYAL AERONAUTICAL SOC PI LONDON PA 4 HAMILTON PL, LONDON W1J 7BQ, ENGLAND SN 0001-9240 J9 AERONAUT J JI Aeronaut. J. PD JUN PY 2003 VL 107 IS 1072 BP 301 EP + PG 6 WC Engineering, Aerospace SC Engineering GA 699UT UT WOS:000184074900003 ER PT J AU Gaines, DM Regli, WC AF Gaines, DM Regli, WC TI Special Issue: New artificial intelligence paradigms for manufacturing SO AI EDAM-ARTIFICIAL INTELLIGENCE FOR ENGINEERING DESIGN ANALYSIS AND MANUFACTURING LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Drexel Univ, Coll Engn, Dept Comp Sci, Philadelphia, PA 19104 USA. RP Gaines, DM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 126-347, Pasadena, CA 91109 USA. NR 0 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 0890-0604 J9 AI EDAM JI AI EDAM-Artif. Intell. Eng. Des. Anal. Manuf. PD JUN PY 2003 VL 17 IS 3 BP 171 EP 171 DI 10.1017/S089006043173015 PG 1 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Engineering, Multidisciplinary; Engineering, Manufacturing SC Computer Science; Engineering GA 758FV UT WOS:000187623900001 ER PT J AU Rogers, SE Suhs, NE Dietz, WE AF Rogers, SE Suhs, NE Dietz, WE TI PEGASUS 5: An automated preprocessor for overset-grid computational fluid dynamics SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 32nd Fluids Conference CY JUN 24-26, 2002 CL ST LOUIS, MISSOURI SP AIAA AB An all new, automated version of the PEGASUS software has been developed and tested. PEGASUS provides the hole-cutting and connectivity information between overlapping grids and is used as the final part of the grid-generation process for overset-grid computational fluid dynamics approaches. The new PEGASUS code (Version 5) has many new features: automated hole cutting, a projection scheme for fixing small discretization errors in overset surfaces, more efficient interpolation search methods using an alternating digital tree and a stencil-jumping scheme, hole-size optimization based on adding additional layers of fringe points, and an automatic restart capability. The new code has also been parallelized using the message-passing interface standard. The parallelization performance provides efficient speedup of the execution time by an order of magnitude, and up to a factor of 30 for very large problems. The results of two example cases are presented: a three-element high-lift airfoil and a complete Boeing 777-200 aircraft in a high-lift landing configuration. Comparisons of the computed flowfields for these test cases between the old and new versions of the PEGASUS codes show excellent agreement with each other and with experimental results. C1 NASA, Ames Res Ctr, Adv Supercomp Div, Moffett Field, CA 94035 USA. USA, Aviat & Missile Command, Aviat Engn Directorate, Aeromech Div, Redstone Arsenal, AL 35898 USA. Flow Anal Inc, Tullahoma, TN 37330 USA. RP Rogers, SE (reprint author), NASA, Ames Res Ctr, Adv Supercomp Div, Mail Stop T27B-1, Moffett Field, CA 94035 USA. NR 24 TC 35 Z9 42 U1 1 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD JUN PY 2003 VL 41 IS 6 BP 1037 EP 1045 DI 10.2514/2.2070 PG 9 WC Engineering, Aerospace SC Engineering GA 685EB UT WOS:000183246900006 ER PT J AU Garza, FR Zuckerwar, AJ Shams, QA Hopson, P AF Garza, FR Zuckerwar, AJ Shams, QA Hopson, P TI Wide-temperature electronically scanned pressure measurement module SO AIAA JOURNAL LA English DT Article AB Wide-temperature electronically scanned pressure (ESP) measurement modules have been developed for wind-tunnel applications for service over a wide temperature range [50degreesC (122degreesF) to -175degreesC (-283degreesF)]. These modules are designed to account for offset voltage drift, operate without thermal protection in cryogenic temperature environments, and maintain a stable calibration for months. Conventional ESP modules cannot operate in cryogenic environments without thermal protection, for example, a heater box, which reduces available space for module installation, demands labor-intensive and time-consuming installation, and requires heavy electrical wiring that can shunt the wind-tunnel force balance. To account for force-balance shunting, separate wind-tunnel tests must be conducted to collect pressure and force-balance measurements, which devour both time and money. Because of offset voltage drift, conventional modules also require frequent test interruptions for online calibration, which can consume as much as 15% of total test time. Wide-temperature ESP modules eliminate these shortcomings while providing total uncertainty in pressure measurement less than 0.1% of full-scale output. Design, fabrication, and calibration of these modules are described. Test results from data gathered using two 16-port wide-temperature modules in the National Transonic Facility wind tunnel at NASA Langley Research Center are also provided. C1 NASA, Langley Res Ctr, Adv Measurement & Diagnost Branch, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Elect Applicat Technol Branch, Hampton, VA 23681 USA. Swales Aerosp Inc, Hampton, VA 23681 USA. RP Garza, FR (reprint author), Swales Aerosp Inc, 1224T11 N Wright St, Hampton, VA 23681 USA. EM a.j.zuckerwar@larc.nasa.gov NR 5 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD JUN PY 2003 VL 41 IS 6 BP 1097 EP 1104 DI 10.2514/2.2050 PG 8 WC Engineering, Aerospace SC Engineering GA 685EB UT WOS:000183246900013 ER PT J AU Basu, S Waas, AM Ambur, DR AF Basu, S Waas, AM Ambur, DR TI Computational modeling of damage growth in composite laminates SO AIAA JOURNAL LA English DT Article ID COMPRESSIVE FAILURE; FIBER COMPOSITES; BEHAVIOR; PREDICTION AB A progressive damage growth model is developed for composite laminates under compression. The mechanics of damage initiation and growth in a single lamina is modeled in a two-dimensional plane stress setting, using a system of orthotropic nonlinear elastic relations and a set of internal state variables. The latter are associated with different damage mechanisms that are unique to a fiber-reinforced lamina. A thermodynamically consistent set of equations is developed for the evolution of damage growth. The formulation is numerically implemented using the commercially available finite element package ABAQUS. The present method is applied to analyze the problem of damage growth in a compressively loaded notched laminate. Predictions of the model compared against available experimental observations are promising. C1 Univ Michigan, Dept Aerosp Engn, Composite Struct Lab, Ann Arbor, MI 48109 USA. NASA, Langley Res Ctr, Mech & Durabil Branch, Hampton, VA 23681 USA. RP Basu, S (reprint author), Univ Michigan, Dept Aerosp Engn, Composite Struct Lab, Ann Arbor, MI 48109 USA. NR 19 TC 5 Z9 5 U1 0 U2 6 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD JUN PY 2003 VL 41 IS 6 BP 1158 EP 1166 DI 10.2514/2.2059 PG 9 WC Engineering, Aerospace SC Engineering GA 685EB UT WOS:000183246900021 ER PT J AU Centrella, JM AF Centrella, JM TI Resource letter: GrW-1: Gravitational waves SO AMERICAN JOURNAL OF PHYSICS LA English DT Article AB This Resource Letter provides a guide to the literature on the physics and astrophysics of gravitational waves. Journals, books, reports, archives, and websites are provided as basic resources and for current research frontiers in detectors, data analysis, and astrophysical source modeling. (C) 2003 American Association of Physics Teachers. [DOI: 10.1119/1.1543555]. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Centrella, JM (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU AMER ASSOC PHYSICS TEACHERS AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0002-9505 J9 AM J PHYS JI Am. J. Phys. PD JUN PY 2003 VL 71 IS 6 BP 520 EP 525 DI 10.1119/1.1543555 PG 6 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA 679WP UT WOS:000182945200003 ER PT J AU Venkatesan, MI Ruth, E Rao, PS Nath, BN Rao, BR AF Venkatesan, MI Ruth, E Rao, PS Nath, BN Rao, BR TI Hydrothermal petroleum in the sediments of the Andaman Backarc Basin, Indian Ocean SO APPLIED GEOCHEMISTRY LA English DT Article ID POLYCYCLIC AROMATIC-HYDROCARBONS; NORTHEAST PACIFIC-OCEAN; MARINE-SEDIMENTS; ORGANIC-MATTER; GUAYMAS BASIN; SEA SEDIMENTS; CRUDE OILS; GEOCHEMISTRY; CALIFORNIA; RIDGE AB Recent sediments of the Andaman Backare Basin, Indian Ocean, between the Andaman Nicobar islands and the Malay Peninsula have been analyzed for biomarker lipids. Three cores were selected: one each from the fault zone in a deep basin (a graben between two fault systems), another from a location adjacent to the fault, and the third from the topographic high in the rift valley. The molecular composition of the lipid classes (n-alkanes, isoprenoids, alkylbenzenes, alkylcyclohexanes, hopanoids, polycyclic aromatic hydrocarbons, steranes, alcohols, sterols and fatty acids) was examined by gas chromatography (GC) and GC/mass spectrometry to understand the nature and source of the hydrocarbons present and the processes of maturation of organic matter. The data show that the hydrocarbons are of hydrothermal origin, derived from thermal alteration of sedimentary organic matter, consisting of a mixture predominantly of marine-derived components with some terrestrial inputs. Normal alcohols and fatty acids also corroborate the distribution of n-alkanes. The distribution profiles and various parameters computed from the concentration of the target compounds suggest that oxidative reactions and microbial degradation in this environment are insignificant. Triterpane and PAH compositions indicate that the thermal maturity of the bitumen in the samples is comparable to or lower than that found at other hydrothermal regions such as the Northern Juan de Fuca Ridge, Guaymas Basin and Escanaba Trough. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. NASA, Astrobiol Inst, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Civil & Environm Engn, Los Angeles, CA 90095 USA. Natl Inst Oceanog, Panaji 403004, Goa, India. RP Venkatesan, MI (reprint author), Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. NR 56 TC 25 Z9 27 U1 1 U2 14 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0883-2927 J9 APPL GEOCHEM JI Appl. Geochem. PD JUN PY 2003 VL 18 IS 6 BP 845 EP 861 AR PII S0883-2927(02)00180-4 DI 10.1016/S0883-2927(02)00180-4 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 672KV UT WOS:000182520500005 ER PT J AU Swanson, TD Birur, GC AF Swanson, TD Birur, GC TI NASA thermal control technologies for robotic spacecraft SO APPLIED THERMAL ENGINEERING LA English DT Article; Proceedings Paper CT 12th International Heat Pipe Conference CY MAY 19-24, 2002 CL RUSSIA DE advanced thermal control; capillary pumped loops; loop heat pipes; variable emissivity surface; cryogenic; heat switches; thermal storage AB Technology development is inevitably a dynamic process-in search of an elusive goal. It is never truly clear whether the need for a particular technology drives its development, or the existence of a new capability initiates new applications. Technology development for the thermal control of spacecraft presents an excellent example of this situation. Nevertheless, it is imperative to have a basic plan to help guide and focus such an effort. Although this plan will be a living document that changes with time to reflect technological developments, perceived needs, perceived opportunities, and the ever-changing funding environment, it is still a very useful tool, This presentation. summarizes the current efforts at National Aeronautics, and Space Administration (NASA)/Goddard and NASA/JPL to develop new thermal control technology for future robotic-NASA missions. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Swanson, TD (reprint author), NASA, Goddard Space Flight Ctr, Code 540, Greenbelt, MD 20771 USA. NR 13 TC 69 Z9 83 U1 5 U2 22 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-4311 J9 APPL THERM ENG JI Appl. Therm. Eng. PD JUN PY 2003 VL 23 IS 9 BP 1055 EP 1065 DI 10.1016/S1359-4311(03)00036-X PG 11 WC Thermodynamics; Energy & Fuels; Engineering, Mechanical; Mechanics SC Thermodynamics; Energy & Fuels; Engineering; Mechanics GA 682GD UT WOS:000183082600002 ER PT J AU Grymes, R AF Grymes, R TI A tribute to the Columbia mission crew SO ASTROBIOLOGY LA English DT Editorial Material C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Grymes, R (reprint author), NASA, Ames Res Ctr, MS 240-1, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD SUM PY 2003 VL 3 IS 2 BP 217 EP 218 DI 10.1089/153110703769016280 PG 2 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 726FM UT WOS:000185588100001 PM 14577869 ER PT J AU Marais, DJD Allamandola, LJ Benner, SA Boss, AP Deamer, D Falkowski, PG Farmer, JD Hedges, SB Jakosky, BM Knoll, AH Liskowsky, DR Meadows, VS Meyer, MA Pilcher, CB Nealson, KH Spormann, AM Trent, JD Turner, WW Woolf, NJ Yorke, HW AF Marais, DJD Allamandola, LJ Benner, SA Boss, AP Deamer, D Falkowski, PG Farmer, JD Hedges, SB Jakosky, BM Knoll, AH Liskowsky, DR Meadows, VS Meyer, MA Pilcher, CB Nealson, KH Spormann, AM Trent, JD Turner, WW Woolf, NJ Yorke, HW TI The NASA astrobiology roadmap SO ASTROBIOLOGY LA English DT Article AB The NASA Astrobiology Roadmap provides guidance for research and technology development across the NASA enterprises that encompass the space, Earth, and biological sciences. The ongoing development of astrobiology roadmaps embodies the contributions of diverse scientists and technologists from government, universities, and private institutions. The Roadmap addresses three basic questions: How does life begin and evolve, does life exist elsewhere in the universe, and what is the future of life on Earth and beyond? Seven Science Goals outline the following key domains of investigation: understanding the nature and distribution of habitable environments in the universe, exploring for habitable environments and life in our own solar system, understanding the emergence of life, determining how early life on Earth interacted and evolved with its changing environment, understanding the evolutionary mechanisms and environmental limits of life, determining the principles that will shape life in the future, and recognizing signatures of life on other worlds and on early Earth. For each of these goals, Science Objectives outline more specific high-priority efforts for the next 3-5 years. These 18 objectives are being integrated with NASA strategic planning. C1 NASA, Ames Res Ctr, Space Sci Div, Moffett Field, CA 94035 USA. Univ Florida, Dept Chem, Gainesville, FL 32611 USA. Fdn Appl Mol Evolut, Gainesville, FL 32611 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. Univ Calif Santa Cruz, Dept Chem & Biochem, Santa Cruz, CA 95064 USA. Rutgers State Univ, Inst Marine & Coastal Sci, New Brunswick, NJ 08903 USA. Rutgers State Univ, Dept Geol, New Brunswick, NJ 08903 USA. Arizona State Univ, Dept Geol Sci, Tempe, AZ USA. Penn State Univ, Dept Biol, University Pk, PA 16802 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. Harvard Univ, Dept Organism & Evolutionary Biol, Cambridge, MA 02138 USA. NASA Headquarters, Washington, DC USA. CALTECH, SIRTF Sci Ctr, Pasadena, CA 91125 USA. CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. Univ So Calif, Dept Earth Sci, Los Angeles, CA USA. Stanford Univ, Dept Civil & Environm Engn, Stanford, CA 94305 USA. Univ Arizona, Dept Astron, Tucson, AZ USA. RP Marais, DJD (reprint author), NASA, Ames Res Ctr, Space Sci Div, Mail Stop 239-4, Moffett Field, CA 94035 USA. NR 0 TC 3 Z9 3 U1 2 U2 12 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD SUM PY 2003 VL 3 IS 2 BP 219 EP 235 PG 17 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 726FM UT WOS:000185588100002 ER PT J AU McKay, CP Friedmann, EI Frankel, RB Bazylinski, DA AF McKay, CP Friedmann, EI Frankel, RB Bazylinski, DA TI Magnetotactic bacteria on Earth and on Mars SO ASTROBIOLOGY LA English DT Review DE Mars; magnetite; ALH84001; life ID MARTIAN METEORITE ALH84001; SP STRAIN AMB-1; MAGNETITE CRYSTALS; MAGNETOSPIRILLUM-GRYPHISWALDENSE; BIOGENIC MAGNETITE; ALLAN-HILLS-84001; CARBONATES; PROTEIN; ORIGIN; MAGNETOFOSSILS AB Continued interest in the possibility of evidence for life in the ALH84001 Martian meteorite has focused on the magnetite crystals. This review is structured around three related questions: Is the magnetite in ALH84001 of biological or non-biological origin, or a mixture of both? Does magnetite on Earth provide insight to the plausibility of biogenic magnetite on Mars? Could magnetotaxis have developed on Mars? There are credible arguments for both the biological and non-biological origin of the magnetite in ALH84001, and we suggest that more studies of ALH84001, extensive laboratory simulations of non-biological magnetite formation, as well as further studies of magnetotactic bacteria on Earth will be required to further address this question. Magnetite grains produced by bacteria could provide one of the few inorganic traces of past bacterial life on Mars that could be recovered from surface soils and sediments. If there was biogenic magnetite on Mars in sufficient abundance to leave fossil remains in the volcanic rocks of ALH84001, then it is likely that better-preserved magnetite will be found in sedimentary deposits on Mars. Deposits in ancient lakebeds could contain well-preserved chains of magnetite clearly indicating a biogenic origin. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. California Polytech STate Univ San Luis Obispo, Dept Phys, San Luis Obispo, CA USA. Iowa State Univ, Dept Microbiol, Ames, IA USA. RP McKay, CP (reprint author), NASA, Ames Res Ctr, Div Space Sci, Code 245-3, Moffett Field, CA 94035 USA. NR 42 TC 13 Z9 17 U1 3 U2 14 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD SUM PY 2003 VL 3 IS 2 BP 263 EP 270 DI 10.1089/153110703769016361 PG 8 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 726FM UT WOS:000185588100008 PM 14577877 ER PT J AU Hill, HGM Nuth, JA AF Hill, HGM Nuth, JA TI The catalytic potential of cosmic dust: Implications for prebiotic chemistry in the solar nebula and other protoplanetary systems SO ASTROBIOLOGY LA English DT Article DE astrochemistry; origin of life; interstellar dust; catalysis; prebiotic molecules; Fischer-Tropsch synthesis; Haber-Bosch synthesis ID ORGANIC-MOLECULES; PRIMITIVE EARTH; COMETS; CO; ORIGIN; ATMOSPHERES; METEORITES; HYAKUTAKE; ANALOGS; SPECTRA AB The synthesis of important prebiotic molecules is fundamentally reliant on basic starting ingredients: water, organic species [e.g., methane (CH4)] and reduced nitrogen compounds [e.g., ammonia (NH3), methyl cyanide (CH3CN) etc.]. However, modern studies conclude that the primordial Earth's atmosphere was too rich in CO, CO2, and water to permit efficient synthesis of such reduced molecules as envisioned by the classic Miller-Urey experiment. Other proposed sources of terrestrial nitrogen reduction, like those within submarine vent systems, also seem to be inadequate sources of chemically reduced C-H-O-N compounds. Here, we demonstrate that nebular dust analogs have impressive catalytic properties for synthesizing prebiotic molecules. Using a catalyst analogous to nebular iron silicate condensate, at temperatures ranging from 500K to 900K, we catalyzed both the Fischer-Tropsch conversion of CO and H-2 to methane and water, and the corresponding Haber-Bosch synthesis of ammonia from N-2 and H-2. Remarkably, when CO, N-2, and H-2 were allowed to react simultaneously, these syntheses also yielded nitrogen-containing organics such as methyl amine (CH3NH2), acetonitrile (CH3CN), and N-methyl methylene imine (H3CNCH2). A fundamental consequence of this work for astrobiology is the potential for a natural chemical pathway to produce complex chemical building blocks of life throughout our own Solar System and beyond. C1 Int Space Univ, F-67400 Illkirch Graffenstaden, France. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD USA. RP Hill, HGM (reprint author), Int Space Univ, Strasbourg Cent Campus,Parc Innovat, F-67400 Illkirch Graffenstaden, France. RI Nuth, Joseph/E-7085-2012 NR 39 TC 42 Z9 44 U1 1 U2 19 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD SUM PY 2003 VL 3 IS 2 BP 291 EP 304 DI 10.1089/153110703769016389 PG 14 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 726FM UT WOS:000185588100010 PM 14577878 ER PT J AU McKay, CP Friedmann, EI Gomez-Silva, B Caceres-Villanueva, L Andersen, DT Landheim, R AF McKay, CP Friedmann, EI Gomez-Silva, B Caceres-Villanueva, L Andersen, DT Landheim, R TI Temperature and moisture conditions for life in the extreme arid region of the Atacama Desert: Four years of observations including the El Nino of 1997-1998 SO ASTROBIOLOGY LA English DT Article DE Atacama Desert; extreme environments; Mars; hypolithic cyanobacteria ID NORTHERN CHILE; NITRATE DEPOSITS; WATER-MOVEMENT; SURFACE ROCKS; LIQUID WATER; FIELD SOIL; ANTOFAGASTA; OSCILLATION; EVOLUTION; RECORD AB The Atacama along the Pacific Coast of Chile and Peru is one of the driest and possibly oldest deserts in the world. It represents an extreme habitat for life on Earth and is an analog for life in dry conditions on Mars. We report on four years (September 1994-October 1998) of climate and moisture data from the extreme and region of the Atacama. Our data are focused on understanding moisture sources and their role in creating suitable environments for photosynthetic microorganisms in the desert surface. The average air temperature was 16.5degreesC and 16.6degreesC in 1995 and 1996, respectively. The maximum air temperature recorded was 37.9degreesC, and the minimum was -5.7degreesC. Annual average sunlight was 336 and 335 W m(-2) in 1995 and 1996, respectively. Winds averaged a few meters per second, with strong fohn winds coming from the west exceeding 12 m s(-1). During our 4 years of observation there was only one significant rain event of 2.3 mm, which occurred near midnight local time. We suggest that this event was a rainout of a heavy fog. It is of interest that the strong El Nino of 1997-1998 brought heavy rainfall to the deserts of Peru, but did not bring significant rain to the central Atacama in Chile. Dew occurred at our station frequently following high nighttime relative humidity, but is not a significant source of moisture in, the soil or under stones. Groundwater also does not contribute to surface moisture. Only the one rain event of 2.3 mm resulted in liquid water in the soil and beneath stones for a total of only 65-85 h over 4 years. The paucity of liquid water under stones is consistent with the apparent absence of hypolithic (under-stone) cyanobacteria, the only known primary producers in such extreme deserts. C1 NASA, Ames Res Ctr, Space Sci Div, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. Univ Antofagasta, Dept Biomed, Antofagasta, Chile. Univ Antofagasta, Inst Desierto, Antofagasta, Chile. RP McKay, CP (reprint author), NASA, Ames Res Ctr, Space Sci Div, Moffett Field, CA 94035 USA. NR 30 TC 141 Z9 147 U1 4 U2 46 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD SUM PY 2003 VL 3 IS 2 BP 393 EP 406 DI 10.1089/153110703769016460 PG 14 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 726FM UT WOS:000185588100018 PM 14577886 ER PT J AU Stern, D Holden, B Stanford, SA Spinrad, H AF Stern, D Holden, B Stanford, SA Spinrad, H TI Confirmation of a radio-selected galaxy overdensity at z=1.11 SO ASTRONOMICAL JOURNAL LA English DT Article DE cosmology : observations; galaxies : active; galaxies : evolution; galaxies : individual (MG1 J044226+0202); X-rays ID INFRARED STANDARD STARS; DARK MATTER THEORY; 5 GHZ SURVEY; X-RAY; HIGH-REDSHIFT; CHANDRA OBSERVATIONS; ELLIPTIC GALAXIES; CLUSTER EVOLUTION; RICH CLUSTERS; DEEP SURVEY AB We report the discovery of a galaxy overdensity at z=1.11 associated with the z=1.110 high-redshift radio galaxy MG1 J04426+0202 (hereafter MG 0442+0202). The group, Cl 0442+0202, was found in a near-infrared survey of z>1 radio galaxies undertaken to identify spatially coincident regions with a high density of objects red in I-K' color, typical of z>1 elliptical galaxies. Spectroscopic observations from the Keck I telescope reveal five galaxies within 35" of MG 0442+0202 at 1.105x10(-16) ergs cm(-2) s(-1)]. One of these point sources is identified with a radio-quiet type II quasar at z=1.863, akin to sources recently reported in deep Chandra surveys. The limit on an extended hot intracluster medium in the Chandra data is S(1-6 keV)<1.9x10(-15) ergs cm(-2) s(-1) (3σ, 30&DPRIME; radius aperture). Though the X-ray observations do not confirm the existence of a massive bound cluster at z>1, the success of the optical/near-infrared targeting of early-type systems near the radio galaxy validates searches using radio galaxies as beacons for high-redshift large-scale structure. We interpret Cl 0442+0202 as a massive cluster in the process of formation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RP Stern, D (reprint author), CALTECH, Jet Prop Lab, MS 169-327,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 70 TC 24 Z9 24 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 2003 VL 125 IS 6 BP 2759 EP 2768 DI 10.1086/374229 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 684YM UT WOS:000183234100001 ER PT J AU Martel, AR Ford, HC Tran, HD Illingworth, GD Krist, JE White, RL Sparks, WB Gronwall, C Cross, NJG Hartig, GF Clampin, M Ardila, DR Bartko, F Benitez, N Blakeslee, JP Bouwens, RJ Broadhurst, TJ Brown, RA Burrows, CJ Cheng, ES Feldman, PD Franx, M Golimowski, DA Infante, L Kimble, RA Lesser, MP McCann, WJ Menanteau, F Meurer, GR Miley, GK Postman, M Rosati, P Sirianni, M Tsvetanov, ZI Zheng, W AF Martel, AR Ford, HC Tran, HD Illingworth, GD Krist, JE White, RL Sparks, WB Gronwall, C Cross, NJG Hartig, GF Clampin, M Ardila, DR Bartko, F Benitez, N Blakeslee, JP Bouwens, RJ Broadhurst, TJ Brown, RA Burrows, CJ Cheng, ES Feldman, PD Franx, M Golimowski, DA Infante, L Kimble, RA Lesser, MP McCann, WJ Menanteau, F Meurer, GR Miley, GK Postman, M Rosati, P Sirianni, M Tsvetanov, ZI Zheng, W TI Coronagraphic imaging of 3C 273 with the advanced camera for surveys SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : nuclei; quasars : general; quasars : individual (3C 273) ID HUBBLE-SPACE-TELESCOPE; NEARBY LUMINOUS QUASARS; REDSHIFT RADIO GALAXIES; DUST DISKS; 3C-273; JET; EMISSION; IMAGES; SPECTROSCOPY; ULTRAVIOLET AB The nearby and luminous QSO 3C 273 was imaged in 2002 July with the High Resolution Channel (HRC) of the Advanced Camera for Surveys (ACS) in coronagraphic mode in F475W (g), F606W (V), and F814W (I) as part of the Early Release Observations (ERO) program. After subtraction of the remaining PSF of the QSO, these images offer the most detailed view yet of the morphology and colors of the host galaxy of this QSO. We find that the central light distribution is elongated along the jet axis and its outer edge is delineated by an arc, centered on the jet at a radius of similar to2."6 from the QSO and bluer than the surrounding galaxy. This system is embedded in an extended galactic halo. Compared with early-type galaxies of similar redshifts and luminosities, the light distribution of 3C 273 is flatter in the core, likely from suppression by dust, but similar in the outer halo. The QSO is displaced from the isophotal center of the galaxy by similar to1."4. Previously known emission-line extensions are confirmed and new morphological features are identified, including a dramatic spiral-shaped plume, two faint. laments, a dust lane, and a knot along the jet axis. Part of the inner jet is unambiguously detected in all three bandpasses, and its morphology matches that of a MERLIN radio map. Different mechanisms that could explain the morphology of 3C 273 are considered, such as scattered QSO radiation, a face-on disk, and a merger event. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Bartko Sci & Technol, Mead, CO 80542 USA. Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Leiden Observ, NL-2300 RA Leiden, Netherlands. Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago 22, Chile. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. European So Observ, D-85748 Garching, Germany. RP Martel, AR (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. RI White, Richard/A-8143-2012; Clampin, mark/D-2738-2012; Kimble, Randy/D-5317-2012; OI Benitez, Narciso/0000-0002-0403-7455; Blakeslee, John/0000-0002-5213-3548 NR 40 TC 15 Z9 15 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 2003 VL 125 IS 6 BP 2964 EP 2974 DI 10.1086/375205 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 684YM UT WOS:000183234100014 ER PT J AU Miskey, CL Bruhweiler, FC AF Miskey, CL Bruhweiler, FC TI STIS spectral imagery of the ob stars in NGC 604. I. Description of the extraction technique for a crowded stellar field SO ASTRONOMICAL JOURNAL LA English DT Article DE instrumentation : high angular resolution; instrumentation : spectrographs; ISM : individual (NGC 604); techniques : image processing; techniques : spectroscopic AB We have developed a data reduction procedure to extract multiple spectra from a single two-dimensional Space Telescope Imaging Spectrograph (STIS) image of a crowded stellar field. This paper provides a description of our new technique, utilizing a STIS ultraviolet spectral image, acquired with the G140L grating and the 52" x 2" aperture, sampling a concentration of O and B stars in the central region of the NGC 604 starburst in M33. The software routines can disentangle and produce reliable ultraviolet spectra of stars with angular separations as small as 0."055. Use of the extraction slit, based on our model of the spectral cross-dispersion profile, generates spectra with slightly higher resolution than the STScI standard processing. Our results clearly show that the spectral imaging capability of STIS represents a powerful tool for studying luminous stars in the star-forming regions of the Local Group. C1 Catholic Univ Amer, Dept Phys, Inst Astrophys & Computat Sci, Washington, DC 20064 USA. RP Miskey, CL (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 9 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 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 2003 VL 125 IS 6 BP 3071 EP 3081 DI 10.1086/374987 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 684YM UT WOS:000183234100021 ER PT J AU Bruhweiler, FC Miskey, CL Neubig, MS AF Bruhweiler, FC Miskey, CL Neubig, MS TI STIS spectral imagery of the OB stars in NGC 604. II. The most luminous stars SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual (M33); ISM : individual (NGC 604); Local Group; stars : early-type; stars : fundamental parameters; stars : luminosity function, mass function ID LARGE-MAGELLANIC-CLOUD; INITIAL MASS FUNCTION; DISTANCE SCALE; B-STAR; REGIONS; M33; CLASSIFICATION; ATMOSPHERES; IONIZATION; POPULATION AB We present results using two-dimensional spectral imagery and photometry obtained with the HubbleSpace Telescope (HST) for the starburst H II region NGC 604, in the nearby galaxy M33. The spectral imagery was acquired with the Space Telescope Imaging Spectrograph (STIS) using the MAMA-G140L configuration, which provided wavelength coverage spanning 1170-1730 Angstrom. From a single 1720 s STIS exposure, we have extracted spectra for 49 stars and derived individual UV spectral types for 40 stars in the crowded 25" x 2" stellar field sampled by the STIS aperture. These stars represent a significant fraction of the young, luminous O and B stars in NGC 604. Three objects have pronounced He II lambda1640 emission, the signature of Wolf-Rayet (W-R) or luminous Of stars. By combining UV fluxes with HST WF/PC-1 and WFPC2 photometry at visible wavelengths, we derive the extinction curve for NGC 604. We use this extinction curve, together with the available accurate distance for M33, derived UV spectral types, and HST photometry, to determine positions of the luminous stars in the upper Hertzsprung-Russell diagram for NGC 604. The revision to the O star effective temperature scale by Martins et al., based on non-LTE, line-blanketed model atmospheres, is essential in obtaining reliable positions in the log L-*-log T-eff plane. These stars are quite young, with a characteristic age of similar to3 Myr. The spectra and photometry indicate that three objects are exceedingly luminous. Their inferred locations in the H-R diagram relative to theoretical evolutionary tracks indicate stellar masses greater than or equal to120 M-circle dot. High spatial resolution HST imagery provides no evidence of multiple stars composing these objects. Still, we cannot eliminate the possibility that these objects are not unresolved multiple stars of lower mass, possibly W-R stars. Simple tests demonstrate that the 10 most luminous stars predominantly determine the UV spectral features seen in the total light of NGC 604. We conclude that the interpretation of spectral fitting of more distant starburst galaxies, where individual stars are not resolved, must be done with extreme care. C1 Catholic Univ Amer, Dept Phys, Inst Astrophys & Computat Sci, Washington, DC 20064 USA. RP Bruhweiler, FC (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 45 TC 18 Z9 18 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 2003 VL 125 IS 6 BP 3082 EP 3096 DI 10.1086/374988 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 684YM UT WOS:000183234100022 ER PT J AU Tripp, TM Wakker, BP Jenkins, EB Bowers, CW Danks, AC Green, RF Heap, SR Joseph, CL Kaiser, ME Linsky, JL Woodgate, BE AF Tripp, TM Wakker, BP Jenkins, EB Bowers, CW Danks, AC Green, RF Heap, SR Joseph, CL Kaiser, ME Linsky, JL Woodgate, BE TI Complex C: A low-metallicity, high-velocity cloud plunging into the Milky Way SO ASTRONOMICAL JOURNAL LA English DT Review DE Galaxy : abundances; Galaxy : halo; ISM : abundances; ISM : clouds; quasars : individual (3C 351, H1821+643) ID TELESCOPE IMAGING SPECTROGRAPH; ABSORPTION PROFILE SPECTROGRAPH; GALACTIC CHEMICAL EVOLUTION; DARK-MATTER MINIHALOS; H-ALPHA EMISSION; MAGELLANIC STREAM; INTERSTELLAR-MEDIUM; SPACE-TELESCOPE; LOCAL GROUP; PHYSICAL CONDITIONS AB We present evidence that high-velocity cloud (HVC) complex C is a low-metallicity gas cloud that is plunging toward the disk and beginning to interact with the ambient gas that surrounds the Milky Way. This evidence begins with a new high-resolution (7 km s(-1) FWHM) echelle spectrum of 3C 351 obtained with the Space Telescope Imaging Spectrograph ( STIS). 3C 351 lies behind the low-latitude edge of complex C, and the new spectrum provides accurate measurements of O I, Si II, Al II, Fe II, and Si III absorption lines at the velocity of complex C; N I, S II, Si IV, and C IV are not detected at 3 sigma significance in complex C proper. However, Si IV and C IV as well as O I, Al II, Si II and Si III absorption lines are clearly present at somewhat higher velocities associated with a "high-velocity ridge'' (HVR) of 21 cm emission. This high-velocity ridge has a similar morphology to and is roughly centered on complex C proper. The similarities of the absorption-line ratios in the HVR and complex C suggest that these structures are intimately related. In complex C proper we find [O/H] = -0.76(-0.21+)(0.23) For other species the measured column densities indicate that ionization corrections are important. We use collisional and photoionization models to derive ionization corrections; in both models we find that the overall metallicity Z = 0.1 - 0.3 Z(.) in complex C proper, but nitrogen must be under-abundant. The iron abundance indicates that the complex C contains very little dust. The size and density implied by the ionization models indicate that the absorbing gas is not gravitationally confined. The gas could be pressure confined by an external medium, but alternatively we may be viewing the leading edge of the HVC, which is ablating and dissipating as it plunges into the Milky Way. O vi column densities observed with the Far Ultraviolet Spectroscopic Explorer ( FUSE) toward nine QSOs/AGNs behind complex C support this conclusion: N( O vi) is highest near 3C 351, and the O VI/ H I ratio increases substantially with decreasing latitude, suggesting that the lower latitude portion of the cloud is interacting more vigorously with the Galaxy. The other sight lines through complex C show some dispersion in metallicity, but, with the current uncertainties, the measurements are consistent with a constant metallicity throughout the HVC. However, all of the complex C sight lines require significant nitrogen underabundances. Finally, we compare the 3C 351 data with high-resolution STIS observations of the nearby QSO H1821+ 643 to search for evidence of out. owing Galactic fountain gas that could be mixing with complex C. We find that the intermediate-velocity gas detected toward 3C 351 and H1821+ 643 has a higher metallicity and may well be a fountain/chimney outflow from the Perseus spiral arm. However, the results for the higher velocity gas are inconclusive: the HVC detected toward H1821+ 643 near the velocity of complex C could have a similar metallicity to the 3C 351 gas or it could have a significantly higher Z, depending on the poorly constrained ionization correction. C1 Princeton Univ Observ, Princeton, NJ 08544 USA. Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08855 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Tripp, TM (reprint author), Princeton Univ Observ, Peyton Hall, Princeton, NJ 08544 USA. RI Woodgate, Bruce/D-2970-2012; Jenkins, Edward/P-5684-2014 OI Jenkins, Edward/0000-0003-1892-4423 NR 108 TC 100 Z9 100 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 2003 VL 125 IS 6 BP 3122 EP 3144 DI 10.1086/374995 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 684YM UT WOS:000183234100025 ER PT J AU Ishibashi, K Gull, TR Davidson, K Smith, N Lanz, T Lindler, D Feggans, K Verner, E Woodgate, BE Kimble, RA Bowers, CW Kraemer, S Heap, SR Danks, AC Maran, SP Joseph, CL Kaiser, ME Linsky, JL Roesler, F Weistrop, D AF Ishibashi, K Gull, TR Davidson, K Smith, N Lanz, T Lindler, D Feggans, K Verner, E Woodgate, BE Kimble, RA Bowers, CW Kraemer, S Heap, SR Danks, AC Maran, SP Joseph, CL Kaiser, ME Linsky, JL Roesler, F Weistrop, D TI Discovery of a little Homunculus within the Homunculus Nebula of eta Carinae SO ASTRONOMICAL JOURNAL LA English DT Article DE circumstellar matter; ISM : individual (Little Homunculus); ISM : jets and outflows; stars : individual (eta Carinae); stars : mass loss; stars : winds, outflows ID TELESCOPE IMAGING SPECTROGRAPH; BINARY HYPOTHESIS; EJECTA; VELOCITIES; MOTION; LINES AB We report long-slit spectroscopic mapping of the eta Carinae nebula obtained using the Space Telescope Imaging Spectrograph. The observations reveal the presence of a previously unknown bipolar emission nebula ( roughly +/-2" along its major axis) embedded within the well-known and larger Homunculus Nebula. A preliminary analysis suggests that this embedded nebula may have originated from a minor eruption event circa 1890, 50 years after the formation of the larger Homunculus. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Adv Comp Concepts Inc, Potomac, MD 20854 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. SGT Inc, Greenbelt, MD 20770 USA. NASA, Goddard Space Flight Ctr, Space Sci Directorate, Greenbelt, MD 20771 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Wisconsin, Dept Phys, Madison, WI 53711 USA. Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. RP Ishibashi, K (reprint author), MIT, Ctr Space Res, NE80-6011,77 Massachusetts Ave, Cambridge, MA 02139 USA. RI Gull, Theodore/D-2753-2012; Woodgate, Bruce/D-2970-2012 OI Gull, Theodore/0000-0002-6851-5380; NR 38 TC 75 Z9 75 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 2003 VL 125 IS 6 BP 3222 EP 3236 DI 10.1086/375306 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 684YM UT WOS:000183234100033 ER PT J AU Holmes, EK Butner, HM Fajardo-Acosta, SB Rebull, LM AF Holmes, EK Butner, HM Fajardo-Acosta, SB Rebull, LM TI A survey of nearby main-sequence stars for submillimeter emission SO ASTRONOMICAL JOURNAL LA English DT Article DE circumstellar matter; submillimeter radiation; surveys ID KUIPER-BELT; CIRCUMSTELLAR DISK; SOLAR-SYSTEM; DUST DISKS; CATALOG; EXCESS; CLOUD; DEBRIS; GAS; AGE AB We searched for submillimeter emission around 10 Vega-type stars and one Herbig Ae star with the four-color bolometer at 1300 mum and the 19 channel bolometer array at 870 mum using the Heinrich Hertz Telescope at the Submillimeter Telescope Observatory. All of our sources were undetected at 870 mum. In the case of HD 131156, we have a 3 sigma detection at 1300 mum. We report a flux of 6.25 +/- 1.88 mJy for the HD 131156 disk and a corresponding dust mass of 2.4 +/- 0.7 lunar masses. However, we did not detect HD 131156 at 870 mum, so we are cautious about the 1300 mum detection. We performed follow-up infrared observations of HD 131156 using MIRLIN at the Palomar 200 inch telescope, which resolved both components of the binary. The data are photospheric, implying that the system does not have a hot, inner dust component. We report submillimeter upper limits on fluxes for the remaining systems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Steward Observ, Submillimeter Telescope Observ, Tucson, AZ 85721 USA. CALTECH, SITF Sci Ctr, Pasadena, CA 91125 USA. RP CALTECH, Jet Prop Lab, MS 169-506,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM holmes@jpl.nasa.gov; hbutner@as.arizona.edu; fajardo@ipac.caltech.edu; rebull@ipac.caltech.edu OI Butner, Harold/0000-0003-4899-2064; Rebull, Luisa/0000-0001-6381-515X NR 40 TC 20 Z9 20 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 EI 1538-3881 J9 ASTRON J JI Astron. J. PD JUN PY 2003 VL 125 IS 6 BP 3334 EP 3343 DI 10.1086/375202 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 684YM UT WOS:000183234100041 ER PT J AU Chauvin, G Thomson, M Dumas, C Beuzit, JL Lowrance, P Fusco, T Lagrange, AM Zuckerman, B Mouillet, D AF Chauvin, G Thomson, M Dumas, C Beuzit, JL Lowrance, P Fusco, T Lagrange, AM Zuckerman, B Mouillet, D TI Adaptive optics imaging survey of the Tucana-Horologium association SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE instrumentation : adaptive optics; stars : imaging; stars : low-mass, brown dwarfs ID BROWN DWARF COMPANION; LOW-MASS STARS; DECONVOLUTION METHOD; EVOLUTIONARY MODELS; STELLAR FIELDS; PROPER MOTION; X-RAY; IMAGES; ASTROMETRY; PHOTOMETRY AB We present the results of an adaptive optics (AO) imaging survey of the common associations of Tucana and Horologium, carried out at the ESO 3.6 m telescope with the ADONIS/SHARPII system. Based on our observations of two dozen probable association members, HIP 1910 and HIP 108422 appear to have low-mass stellar companions, while HIP 6856 and GSC 8047-0232 have possible sub-stellar candidate companions. Astrometric measurements, performed in November 2000 and October 2001, indicate that HIP 1910 B likely is bound to its primary, but are inconclusive in the case of the candidate companion to HIP 6856. Additional observations are needed to confirm the HIP 6856 companionship as well as for HIP 108422 and GSC 8047-0232. C1 Observ Grenoble, Astrophys Lab, F-38041 St Martin Dheres, France. Univ London Imperial Coll Sci Technol & Med, London SW7 2AZ, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Off Natl Etud & Rech Aerosp, Dept Opt Theor & Appl, F-92322 Chatillon, France. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Observ Midi Pyrenees, Astrophys Lab, F-65008 Tarbes, France. RP Chauvin, G (reprint author), Observ Grenoble, Astrophys Lab, 414 Rue Piscine, F-38041 St Martin Dheres, France. NR 23 TC 36 Z9 36 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 2003 VL 404 IS 1 BP 157 EP 162 DI 10.1051/0004-6361:20030352 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 682FP UT WOS:000183081300018 ER PT J AU Masetti, N Palazzi, E Pian, E Simoncelli, A Hunt, LK Maiorano, E Levan, A Christensen, L Rol, E Savaglio, S Falomo, R Castro-Tirado, AJ Hjorth, J Delsanti, A Pannella, M Mohan, V Pandey, SB Sagar, R Amati, L Burud, I Ceron, JMC Frontera, F Fruchter, AS Fynbo, JPU Gorosabel, J Kaper, L Klose, S Kouveliotou, C Nicastro, L Pedersen, H Rhoads, J Salamanca, I Tanvir, N Vreeswijk, PM Wijers, RAMJ van den Heuvel, EPJ AF Masetti, N Palazzi, E Pian, E Simoncelli, A Hunt, LK Maiorano, E Levan, A Christensen, L Rol, E Savaglio, S Falomo, R Castro-Tirado, AJ Hjorth, J Delsanti, A Pannella, M Mohan, V Pandey, SB Sagar, R Amati, L Burud, I Ceron, JMC Frontera, F Fruchter, AS Fynbo, JPU Gorosabel, J Kaper, L Klose, S Kouveliotou, C Nicastro, L Pedersen, H Rhoads, J Salamanca, I Tanvir, N Vreeswijk, PM Wijers, RAMJ van den Heuvel, EPJ TI Optical and near-infrared observations of the GRB020405 afterglow SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma rays : bursts; radiation mechanisms : non-thermal; line : identification; cosmology : observations ID GAMMA-RAY BURST; SOUTHERN SPECTROPHOTOMETRIC STANDARDS; LIGHT CURVES; LINEAR-POLARIZATION; GRB AFTERGLOWS; DUST ECHOES; SN 2002AP; 1ST MONTH; SUPERNOVA; VARIABILITY AB We report on photometric, spectroscopic and polarimetric monitoring of the optical and near-infrared (NIR) afterglow of GRB020405. Ground-based optical observations, performed with 8 different telescopes, started about 1 day after the high-energy prompt event and spanned a period of similar to10 days; the addition of archival HST data extended the coverage up to similar to150 days after the GRB. We report the first detection of the afterglow in NIR bands. The detection of Balmer and oxygen emission lines in the optical spectrum of the host galaxy indicates that the GRB is located at redshift z = 0.691. Fe II and Mg II absorption systems are detected at z = 0.691 and at z = 0.472 in the afterglow optical spectrum. The latter system is likely caused by absorbing clouds in the galaxy complex located similar to2" southwest of the GRB020405 host. Hence, for the first time, the galaxy responsible for an intervening absorption line system in the spectrum of a GRB afterglow is spectroscopically identified. Optical and NIR photometry of the afterglow indicates that, between 1 and 10 days after the GRB, the decay in all bands is consistent with a single power law of index alpha = 1.54 +/- 0.06. The late-epoch VLT J-band and HST optical points lie above the extrapolation of this power law, so that a plateau ( or "bump") is apparent in the VRIJ light curves at 10-20 days after the GRB. The light curves at epochs later than day similar to20 after the GRB are consistent with a power-law decay with index alpha' = 1.85 +/- 0.15. While other authors have proposed to reproduce the bump with the template of the supernova ( SN) 1998bw, considered the prototypical "hypernova", we suggest that it can also be modeled with a SN having the same temporal profile as the other proposed hypernova SN2002ap, but 1.3 mag brighter at peak, and located at the GRB redshift. Alternatively, a shock re-energization may be responsible for the rebrightening. A single polarimetric R-band measurement shows that the afterglow is polarized, with P = 1.5 +/- 0.4% and polarization angle theta = 172degrees +/- 8degrees. Broad-band optical-NIR spectral flux distributions show, in the first days after the GRB, a change of slope across the J band which we interpret as due to the presence of the electron cooling frequency v(c). The analysis of the multiwavelength spectrum within the standard fireball model suggests that a population of relativistic electrons with index p similar to 2.7 produces the optical-NIR emission via synchrotron radiation in an adiabatically expanding blastwave, with negligible host galaxy extinction, and the X-rays via Inverse Compton scattering off lower-frequency afterglow photons. C1 CNR, Ist Astrofis Spaziale & Fis Cosm, Sez Bologna, I-40129 Bologna, Italy. Osserv Astron Trieste, INAF, I-34131 Trieste, Italy. Univ Bologna, Dipartimento Astron, I-40126 Bologna, Italy. CNR, Ist Radioastron, Sez Firenze, I-50125 Florence, Italy. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Inst Astrophys, D-14482 Potsdam, Germany. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Johns Hopkins Univ, Baltimore, MD 21218 USA. Osserv Astron Roma, INAF, I-00040 Monte Porzio Catone, Italy. Osserv Astron Padova, INAF, I-35122 Padua, Italy. CSIC, IAA, E-18080 Granada, Spain. Univ Copenhagen, Astron Observ, DK-2100 Copenhagen, Denmark. LESIA, Observ Paris Meudon, F-92195 Meudon, France. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. State Observ, Naini Tal 263129, Uttaranchal, India. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Real Inst & Observ Armada, Secc Astron, Cadiz 11110, Spain. Univ Ferrara, Dipartmento Fis, I-44100 Ferrara, Italy. Aarhus Univ, Dept Phys & Astron, DK-8000 Aarhus C, Denmark. Thuringer Landessternwarte Tautenburg, D-07778 Tautenburg, Germany. NASA, MSFC, Huntsville, AL 35812 USA. CNR, Ist Astrofis Spaziale & Fis Cosm, Sez Palermo, I-90146 Palermo, Italy. Univ Hertfordshire, Dept Phys Sci, Hatfield AL10 9AB, Herts, England. European So Observ, Santiago 19, Chile. RP Masetti, N (reprint author), CNR, Ist Astrofis Spaziale & Fis Cosm, Sez Bologna, Via Gobetti 101, I-40129 Bologna, Italy. EM masetti@bo.iasf.cnr.it RI Fynbo, Johan/L-8496-2014; Christensen, Lise/M-5301-2014; Hjorth, Jens/M-5787-2014; Nicastro, Luciano/F-5866-2015; Palazzi, Eliana/N-4746-2015; Amati, Lorenzo/N-5586-2015; OI Falomo, Renato/0000-0003-4137-6541; Fynbo, Johan/0000-0002-8149-8298; Christensen, Lise/0000-0001-8415-7547; Hjorth, Jens/0000-0002-4571-2306; Nicastro, Luciano/0000-0001-8534-6788; Amati, Lorenzo/0000-0001-5355-7388; Palazzi, Eliana/0000-0002-8691-7666; Wijers, Ralph/0000-0002-3101-1808; Castro-Tirado, A. J./0000-0003-2999-3563; Hunt, Leslie/0000-0001-9162-2371; Masetti, Nicola/0000-0001-9487-7740; Pian, Elena/0000-0001-8646-4858; Savaglio, Sandra/0000-0003-2354-3238 NR 94 TC 72 Z9 72 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 JUN PY 2003 VL 404 IS 2 BP 465 EP 481 DI 10.1051/0004-6361:20030491 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 685VA UT WOS:000183283300010 ER PT J AU Marsh, MS Walsh, RW De Moortel, I Ireland, J AF Marsh, MS Walsh, RW De Moortel, I Ireland, J TI Joint observations of propagating oscillations with SOHO/CDS and TRACE SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE Sun : corona; Sun : oscillations; Sun : transition region; Sun : UV radiation; waves ID LONGITUDINAL INTENSITY OSCILLATIONS; CORONAL LOOPS; MEASURED PARAMETERS; WAVELET ANALYSIS; REGION; SUNSPOTS; PLUMES AB Joint Observing Program (JOP) 83 Solar and Heliospheric Observatory/Coronal Diagnostic Spectrometer (SOHO/CDS) and Transition Region and Coronal Explorer (TRACE) data is analysed for evidence of propagating intensity oscillations along loop structures in the solar corona. A propagating intensity oscillation with a minimum estimated speed of 50-195 km s(-1) is observed within a TRACE 171 Angstrom coronal loop using a running difference method. Co-spatial and co-temporal CDS and TRACE observations of this loop are analysed using a wavelet analysis method. The TRACE data shows a propagating oscillation with a period of approximate to300 s. This period is also observed with CDS suggesting propagating oscillations at chromospheric, transition region and coronal temperatures in the He I, O V and Mg IX lines. C1 Univ Cent Lancashire, Ctr Astrophys, Preston PR1 2HE, Lancs, England. Univ St Andrews, Sch Math & Stat, St Andrews KY16 9SS, Fife, Scotland. NASA, L3 Commun EER Syst Inc, GSFC, Greenbelt, MD 20771 USA. RP Marsh, MS (reprint author), Univ Cent Lancashire, Ctr Astrophys, Preston PR1 2HE, Lancs, England. RI Marsh, Mike/I-3920-2012 OI Marsh, Mike/0000-0003-2765-0874 NR 17 TC 50 Z9 50 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 JUN PY 2003 VL 404 IS 2 BP L37 EP L41 DI 10.1051/0004-6361:20030709 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 685VA UT WOS:000183283300004 ER PT J AU Trottet, G Schwartz, RA Hurley, K McTiernan, JM Kane, SR Vilmer, N AF Trottet, G Schwartz, RA Hurley, K McTiernan, JM Kane, SR Vilmer, N TI Stereoscopic observations of the giant hard X-ray/gamma-ray solar flare on 1991 June 30 at 0255 UT SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE Sun : activity; Sun : flares; Sun : particle emission; Sun : X-rays, gamma-rays ID GAMMA-RAY; MAGNETIC RECONNECTION; ENERGY-RELEASE; ELECTRON; ACCELERATION; RADIO; CONFIGURATION; EMISSION; ULYSSES; CORONA AB The hard X-ray/gamma-ray (HXR/GR) impulsive burst on 1991 June 30 (similar to0255 UT) was associated with a flare which occured between 2degrees and 12degrees behind the east limb of the Sun. The partially occulted HXR/GR emission from this flare was detected at up to 100 MeV by three instruments on Earth-orbiting spacecraft: the Burst and Transient Source Experiment (BATSE) and the Energetic Gamma-Ray Experiment ( EGRET) on CGRO and by the Payload for High Energy Burst Spectroscopy (PHEBUS) on GRANAT. As seen from the two spacecraft in Earth orbit, the size of the burst corresponds to that of a moderate electron-dominated GR event (Dingus et al. 1994; Vilmer et al. 1999). However, this event is one of the giant flares reported by Kane et al. (1995). It was observed by the Solar X-ray/Cosmic Gamma-Ray Burst Experiment (GRB) on Ulysses, located 135degrees east of the Earth-Sun line. GRB measured the total >28 keV HXR emission from the flare. In this paper we combine HXR observations by GRB and BATSE in order to determine the time evolution of the power-law index gamma of the photon spectrum of the partially occulted HXR emission seen by BATSE and of the fraction R of the partially occulted to the total >28 keV emission. gamma decreased from similar to5.4 to similar to2.6 and R varied from similar to20% at the beginning of the event down to <1% at its maximum. These results indicate that the spatial distribution of the HXR sources was complex, and evolved in the course of the event. While the HXR emission detected by GRB was almost entirely produced at the footpoints of loops by thick-target interactions, a fraction of the HXR emission seen by BATSE likely originated in the unocculted, low density, portion of the HXR emitting loops. The data also show that a small fraction (&SIM;10%) of the HXR emission detected by BATSE in Earth orbit was radiated by a thick-target source on the visible disk. C1 Observ Paris, LESIA, Sect Meudon, F-92195 Meudon, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP Trottet, G (reprint author), Observ Paris, LESIA, Sect Meudon, F-92195 Meudon, France. NR 34 TC 2 Z9 2 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 2003 VL 403 IS 3 BP 1157 EP 1163 DI 10.1051/0004-6361:20030409 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 682FE UT WOS:000183080400039 ER PT J AU Palmeri, P Mendoza, C Kallman, TR Bautista, MA AF Palmeri, P Mendoza, C Kallman, TR Bautista, MA TI A complete set of radiative and Auger rates for K-vacancy states in Fe XVIII-Fe XXV SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE atomic data; atomic processes; X-rays : general ID DIELECTRONIC SATELLITE SPECTRA; R-MATRIX METHOD; CARBON ISOELECTRONIC SEQUENCE; AUTOIONIZATION RATES; ATOMIC DATA; GENERAL PROGRAM; IRON PROJECT; ELECTRON-SCATTERING; SHELL AUGER; IONS AB A complete set of level energies, wavelengths, A-values, and total and partial Auger rates have been computed for transitions involving the K-vacancy states within the n = 2 complex of Fe XVIII-Fe XXV. Three different standard numerical packages are used for this purpose, namely AUTOSTRUCTURE, the Breit-Pauli R-matrix suite (BPRM) and HFR, which allow reliable estimates of the physical effects involved and of the accuracy of the resulting data sets. The Breit interaction is taken into account because its contributions to the small A-values and partial Auger rates cannot be neglected with increasing electron occupancy. Semiempirical adjustments can also lead to large differences in both the radiative and Auger decay data of strongly mixed levels. Several experimental level energies and wavelengths are questioned, and significant discrepancies are found with previously computed decay rates that are attributed to numerical problems. The statistical accuracy of the present level energies and wavelengths is ranked at +/-3 eV and +/-2 mAngstrom, respectively, and that for A-values and partial Auger rates greater than 10(13) s(-1) at better than 20%. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Inst Venezolano Invest Cient, Ctr Fis, Caracas 1020A, Venezuela. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Kallman, TR (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 38 TC 46 Z9 46 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 JUN PY 2003 VL 403 IS 3 BP 1175 EP 1184 DI 10.1051/0004-6361:20030405 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 682FE UT WOS:000183080400041 ER PT J AU Blakeslee, JP Tsvetanov, ZI Riess, AG Ford, HC Illingworth, GD Magee, D Tonry, JL Benitez, N Clampin, M Hartig, GF Meurer, GR Sirianni, M Ardila, DR Bartko, F Bouwens, R Broadhurst, T Cross, N Feldman, PD Franx, M Golimowski, DA Gronwall, C Kimble, R Krist, J Martel, AR Menanteau, F Miley, G Postman, M Rosati, P Sparks, W Strolger, LG Tran, HD White, RL Zheng, W AF Blakeslee, JP Tsvetanov, ZI Riess, AG Ford, HC Illingworth, GD Magee, D Tonry, JL Benitez, N Clampin, M Hartig, GF Meurer, GR Sirianni, M Ardila, DR Bartko, F Bouwens, R Broadhurst, T Cross, N Feldman, PD Franx, M Golimowski, DA Gronwall, C Kimble, R Krist, J Martel, AR Menanteau, F Miley, G Postman, M Rosati, P Sparks, W Strolger, LG Tran, HD White, RL Zheng, W TI Discovery of two distant type Ia supernovae in the Hubble Deep Field-North with the Advanced Camera for Surveys SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; galaxies : high-redshift; supernovae : general supernovae : individual (SN 2002dc, SN 2002dd) ID FARTHEST KNOWN SUPERNOVA; HIGH-REDSHIFT SUPERNOVAE; ACCELERATING UNIVERSE; LIGHT CURVES; OPTICAL-SPECTRA; DATA REDUCTION; K-CORRECTIONS; DECELERATION; EXTINCTION; PHOTOMETRY AB We present observations of the first two supernovae discovered with the recently installed Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST). The supernovae were found in Wide Field Camera images of the Hubble Deep Field-North taken with the F775W, F850LP, and G800L optical elements as part of the ACS guaranteed time observation program. Spectra extracted from the ACS G800L grism exposures confirm that the objects are Type Ia supernovae (SNe Ia) at redshifts z = 0.47 and 0.95. Follow-up HST observations have been conducted with ACS in F775W and F850LP and with the Near-Infrared Camera and Multi-Object Spectrometer in the near-infrared F110W bandpass, yielding a total of nine flux measurements in the three bandpasses over a period of 50 days in the observed frame. We discuss many of the important issues in doing accurate photometry with the ACS. We analyze the multiband light curves using two different fitting methods to calibrate the supernova luminosities and place them on the SNe Ia Hubble diagram. The resulting distances are consistent with the redshift-distance relation of the accelerating universe model, although evolving intergalactic gray dust remains as a less likely possibility. The relative ease with which these SNe Ia were found, confirmed, and monitored demonstrates the potential ACS holds for revolutionizing the field of high-redshift SNe Ia and therefore of testing the accelerating universe cosmology and constraining the "epoch of deceleration." C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Bartko Sci & Technol, Mead, CO 80542 USA. Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. Leiden Observ, NL-2300 Leiden, Netherlands. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. European So Observ, D-85748 Garching, Germany. RP Blakeslee, JP (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RI Clampin, mark/D-2738-2012; OI Benitez, Narciso/0000-0002-0403-7455; Blakeslee, John/0000-0002-5213-3548 NR 58 TC 57 Z9 57 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 2003 VL 589 IS 2 BP 693 EP 703 DI 10.1086/374797 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 681NX UT WOS:000183043200003 ER PT J AU Price, PA Kulkarni, SR Berger, E Fox, DW Bloom, JS Djorgovski, SG Frail, DA Galama, TJ Harrison, FA McCarthy, P Reichart, DE Sari, R Yost, SA Jerjen, H Flint, K Phillips, A Warren, BE Axelrod, TS Chevalier, RA Holtzman, J Kimble, RA Schmidt, BP Wheeler, JC Frontera, F Costa, E Piro, L Hurley, K Cline, T Guidorzi, C Montanari, E Mazets, E Golenetskii, S Mitrofanov, I Anfimov, D Kozyrev, A Litvak, M Sanin, A Boynton, W Fellows, C Harshman, K Shinohara, C Gal-Yam, A Ofek, E Lipkin, Y AF Price, PA Kulkarni, SR Berger, E Fox, DW Bloom, JS Djorgovski, SG Frail, DA Galama, TJ Harrison, FA McCarthy, P Reichart, DE Sari, R Yost, SA Jerjen, H Flint, K Phillips, A Warren, BE Axelrod, TS Chevalier, RA Holtzman, J Kimble, RA Schmidt, BP Wheeler, JC Frontera, F Costa, E Piro, L Hurley, K Cline, T Guidorzi, C Montanari, E Mazets, E Golenetskii, S Mitrofanov, I Anfimov, D Kozyrev, A Litvak, M Sanin, A Boynton, W Fellows, C Harshman, K Shinohara, C Gal-Yam, A Ofek, E Lipkin, Y TI Discovery of GRB 020405 and its late red bump SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID GAMMA-RAY BURST; 25 APRIL 1998; HOST GALAXY; UNUSUAL SUPERNOVA; DUST ECHOES; ERROR BOX; AFTERGLOW; GRB-970228; CALIBRATION; PROGENITOR AB We present the discovery of GRB 020405 made with the Interplanetary Network (IPN). With a duration of 60 s, the burst appears to be a typical long-duration event. We observed the 75 arcmin(2) IPN error region with the Mount Stromlo Observatory's 50 inch robotic telescope and discovered a transient source that subsequently decayed and was also associated with a variable radio source. We identify this source as the afterglow of GRB 020405. Subsequent observations by other groups found varying polarized flux and established a redshift of 0.690 to the host galaxy. Motivated by the low redshift, we triggered observations with WFPC2 on board the Hubble Space Telescope (HST). Modeling the early ground-based data with a jet model, we find a clear red excess over the decaying optical light curves that is present between day 10 and day 141 (the last HST epoch). This bump has the spectral and temporal features expected of an underlying supernova (SN). In particular, the red color of the putative SN is similar to that of the SN associated with GRB 011121 at late time. Restricting the sample of GRBs to those with z < 0.7, a total of five bursts, red bumps at late times are found in GRB 970228, GRB 011121, and GRB 020405. It is possible that the simplest idea, namely, that all long-duration γ-ray bursts have underlying SNe with a modest dispersion in their properties (especially peak luminosity), is sufficient to explain the nondetections. C1 Mt Stromlo & Siding Spring Observ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia. CALTECH, Palomar Observ, Pasadena, CA 91125 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Carnegie Observ, Pasadena, CA 91101 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Board Studies Astron & Astrophys, Santa Cruz, CA 95064 USA. Univ New S Wales, Sch Phys, Sydney, NSW 2052, Australia. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. CNR, Ist Astrofis Spaziale & Fis Cosm, Area Tor Vergata, I-00133 Rome, Italy. Univ Ferrara, Dipartmento Fis, I-44100 Ferrara, Italy. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. Moscow Space Res Inst, Moscow 117810, Russia. Univ Arizona, Dept Planetary Sci, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Tel Aviv Univ, Wise Observ, IL-69978 Tel Aviv, Israel. RP Price, PA (reprint author), Mt Stromlo & Siding Spring Observ, Res Sch Astron & Astrophys, Via Cotter Rd, Weston, ACT 2611, Australia. RI Kimble, Randy/D-5317-2012; Galama, Titus/D-1429-2014; PIRO, LUIGI/E-4954-2013; Golenetskii, Sergey/B-3818-2015; OI Galama, Titus/0000-0002-1036-396X; PIRO, LUIGI/0000-0003-4159-3984; Costa, Enrico/0000-0003-4925-8523; Schmidt, Brian/0000-0001-6589-1287; Schmidt, Brian/0000-0002-8538-9195 NR 48 TC 68 Z9 69 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 2003 VL 589 IS 2 BP 838 EP 843 DI 10.1086/374730 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 681NX UT WOS:000183043200017 ER PT J AU Stothers, RB AF Stothers, RB TI Turbulent pressure in the envelopes of yellow hypergiants and luminous blue variables SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : mass loss; stars : oscillations; stars : variables : other; stars : Wolf-Rayet turbulence ID WOLF-RAYET STARS; MIXING-LENGTH THEORY; MASSIVE STARS; CONVECTION; SIMULATIONS; EVOLUTION; STABILITY; INSTABILITY; PREDICTIONS; METALLICITY AB The manner in which turbulence ( especially turbulent pressure) affects the structure and stability of luminous post-red-supergiant stars is critically evaluated by calculating both realistic and one-zone models of the convective envelopes. In these stars, the remnant outer envelope closely approaches the Eddington limit, with the result that the local gas densities are driven down. Such a tenuous environment promotes high turbulent velocities in the marginally convective layers of the outer envelope. In the hydrogen and helium convection zones, however, the velocities, even though high, fall well below sound velocity, and the temperature gradient there is essentially radiative, making both the turbulent pressure and the turbulent kinetic energy flux structurally unimportant. Instability is tested for by assuming that turbulence adapts either slowly or rapidly to small perturbations, depending on the magnitude of the turbulent velocity. Although the adiabatically stratified iron convection zone lies too deep below the surface to influence the formal dynamical stability or instability of the outer envelope, radiative instability in this zone is increased if supersonic turbulence occurs and generates energetic shocks or if convection is unable to transport all of the super-Eddington luminous flux. It is concluded that turbulent pressure has no significant effect on the formal dynamical instability of the outer envelope in yellow hypergiant stars and luminous blue variables (LBVs), but it may significantly ease the requirement for radiative instability in the brightest and hottest LBVs and in their close relatives, the hydrogen-poor WN stars. Since both dynamical instability and radiative instability lead to a strong dynamical outflow of matter, the unresolved complications arising from supersonic turbulence and from the consequent inapplicability of mixing-length theory render uncertain the predicted domains of instability for the brightest and hottest stars. C1 NASA, Goddard Space Flight Ctr, Inst Space Studies, New York, NY 10025 USA. RP Stothers, RB (reprint author), NASA, Goddard Space Flight Ctr, Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. NR 42 TC 10 Z9 10 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 2003 VL 589 IS 2 BP 960 EP 967 DI 10.1086/374713 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 681NX UT WOS:000183043200027 ER PT J AU Landi, E Bhatia, AK AF Landi, E Bhatia, AK TI Atomic data and emission-line intensities for Ca VII SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; plasmas; Sun : transition region ID CORONAL DIAGNOSTIC SPECTROMETER; EXTREME-ULTRAVIOLET SPECTRUM; OPTICALLY THIN PLASMAS; COLLISION STRENGTHS; RATE COEFFICIENTS; IONS; SOLAR; SI; WAVELENGTHS; TRANSITIONS AB In the present work we calculate energy levels, transition probabilities, and electron-ion collisional excitation rates for the 3s(2)3p(2), 3s3p(3), and 3s(2)3p(3)d configurations of the silicon-like ion Ca VII. The total number of intermediate coupling levels considered is 27. Collision strengths are calculated at seven incident electron energies: 8, 10, 15, 20, 30, 40, and 60 ryd, using the distorted-wave approximation and a five-configuration model. Excitation rate coefficients are calculated by assuming a Maxwellian distribution of velocities and are used to calculate level populations and line emissivities under the assumption of statistical equilibrium. Line intensity ratios are calculated and compared with observed values measured from SERTS and SOHO CDS spectra. The diagnostic potential of Ca VII is demonstrated, with particular emphasis on the possibility of measuring the Ne/Ca relative abundance through simultaneous observations of Ca VII and Ne vi lines. Ca VII proves to be an excellent tool for the study of the first ionization potential effect in the solar transition region. C1 USN, Res Lab, Washington, DC 20375 USA. Artep Inc, Columbia, MD 21044 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Landi, E (reprint author), USN, Res Lab, Code 7660,4555 Overlook Ave SW, Washington, DC 20375 USA. RI Landi, Enrico/H-4493-2011 NR 38 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 JUN 1 PY 2003 VL 589 IS 2 BP 1075 EP 1084 DI 10.1086/374686 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 681NX UT WOS:000183043200038 ER PT J AU Israel, GL Covino, S Perna, R Mignani, R Stella, L Campana, S Marconi, G Bono, G Mereghetti, S Motch, C Negueruela, I Oosterbroek, T Angelini, L AF Israel, GL Covino, S Perna, R Mignani, R Stella, L Campana, S Marconi, G Bono, G Mereghetti, S Motch, C Negueruela, I Oosterbroek, T Angelini, L TI The infrared counterpart to the anomalous X-ray pulsar 1RXS J170849-400910 SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; pulsars : general; pulsars : individual (1RXS J170849-400910); stars : neutron; X-rays : stars ID MAGNETIZED NEUTRON-STARS; FALLBACK DISKS; EXTINCTION; REPEATERS; EMISSION; BURSTS; MODEL; MASS AB We report the discovery of the likely IR counterpart to the anomalous X-ray pulsar (AXP) 1RXS J170849-400910 based on the Chandra High Resolution Camera (imaging detector) X-ray position and the deep optical/IR observations carried out from ESO telescopes and the Canada-France-Hawaii Telescope during 1999-2002. Within the narrow uncertainty region, we found two relatively faint (K' = 20.0 and K' = 17.53) IR objects. Based on their color and position in the J-K' versus J-H diagram, only the brighter object is consistent with the known IR properties of the counterparts to other AXPs. No variability was detected for this source, which is similar to what is observed in the case of 4U 0142+614. Like in other AXPs, we found that the IR flux of 1RXS J170849-400910 is higher than expected for a simple blackbody component extrapolated from the X-ray data. If confirmed, this object would be the fourth IR counterpart to a source of the AXP class and would make the IR excess a likely new characteristic of AXPs. C1 Osserv Astron Roma, INAF, I-00040 Rome, Italy. Osserv Astron Brera, INAF, I-23807 Merate, Lc, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. European So Observ, D-85748 Garching, Germany. European So Observ, Santiago 19, Chile. CNR, IASF, Sez Milano G Occhialini, I-20133 Milan, Italy. Observ Strasbourg, F-67000 Strasbourg, France. Univ Alicante, Dept Fis Ingn Sistemas & Teor Senales, E-03080 Alicante, Spain. European Space Agcy, European Space Res & Technol Ctr, Dept Astrophys, NL-2200 AG Noordwijk, Netherlands. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Israel, GL (reprint author), Osserv Astron Roma, INAF, Via Frascati 33, I-00040 Rome, Italy. RI Negueruela, Ignacio/L-5483-2014; OI Negueruela, Ignacio/0000-0003-1952-3680; MEREGHETTI, SANDRO/0000-0003-3259-7801; Israel, GianLuca/0000-0001-5480-6438; Covino, Stefano/0000-0001-9078-5507 NR 36 TC 44 Z9 44 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 2003 VL 589 IS 2 BP L93 EP L96 DI 10.1086/375832 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 681NZ UT WOS:000183043400009 ER PT J AU Phillips, KJH Sylwester, J Sylwester, B Landi, E AF Phillips, KJH Sylwester, J Sylwester, B Landi, E TI Solar flare abundances of potassium, argon, and sulphur SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : abundances; Sun : corona; Sun : flares; Sun : X-rays, gamma rays ID OPTICALLY THIN PLASMAS; ELEMENT ABUNDANCES; CORONAL ABUNDANCES; ATOMIC DATABASE; EMISSION-LINES; CHIANTI; SPECTRA; CALCIUM; SUN AB The absolute abundance of potassium has been determined for the first time from X-ray solar flare line and continuum spectra. The absolute and relative abundances of Ar and S have also been determined. Assuming that the flare plasma is coronal, and since potassium has the lowest first ionization potential (FIP) of any common element on the Sun, this determination is of importance in the continuing debate concerning the nature of the coronal/photospheric element abundance ratios, which are widely considered to depend on the FIP. The measurements were made with the RESIK crystal spectrometer on the Coronas-F spacecraft. A differential emission measure DEM proportional to exp (-betaT(e)) was found to be the most consistent with the data of three models considered. We find that the K/H abundance ratio is (3.7 +/- 1.0) x 10(-7), a factor of 3 times photospheric. Our measured values of the Ar/H ratio, (2.8 +/- 0.2) x 10(-6), and of the S/H ratio, (2.2 +/- 0.4) x 10(-5), are equal to previous coronal and photospheric determinations to within uncertainties. These measurements therefore fit a pattern in which low-FIP elements are enriched in the corona by a factor 3 and in which high-FIP elements (including S) have equal coronal and photospheric abundances. C1 NASA, Natl Res Council, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Polish Acad Sci, Space Res Ctr, PL-51622 Wroclaw, Poland. Artep Inc, Ellicott, MD 21042 USA. USN, EO Hulburt Ctr Space Res, Res Lab, Washington, DC 20375 USA. RP Phillips, KJH (reprint author), NASA, Natl Res Council, Goddard Space Flight Ctr, Code 682, Greenbelt, MD 20771 USA. RI Landi, Enrico/H-4493-2011 NR 18 TC 33 Z9 33 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 2003 VL 589 IS 2 BP L113 EP L116 DI 10.1086/375853 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 681NZ UT WOS:000183043400014 ER PT J AU Teplitz, HI Collins, NR Gardner, JP Hill, RS Heap, SR Lindler, DJ Rhodes, J Woodgate, BE AF Teplitz, HI Collins, NR Gardner, JP Hill, RS Heap, SR Lindler, DJ Rhodes, J Woodgate, BE TI Emission-line galaxies in the Space Telescope Imaging Spectrograph parallel survey. 1. Observations and data analysis SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE cosmology : observations; galaxies : evolution; galaxies : fundamental parameters ID REDSHIFT SURVEY; STAR-FORMATION; LUMINOSITY FUNCTION; DEEP FIELD; SPECTRA; POPULATION; ABUNDANCES; CATALOG; SAMPLE AB In the first 3 years of operation the Space Telescope Imaging Spectrograph (STIS) obtained slitless spectra of similar to2500 fields in parallel to prime Hubble Space Telescope (HST) observations as part of the STIS parallel survey (SPS). The archive contains similar to300 fields at high Galactic latitude (\b\>30degrees) with spectroscopic exposure times greater than 3000 s. This sample contains 219 fields (excluding special regions and requiring a consistent grating angle) observed between 1997 June 6 and 2000 September 21, with a total survey area of similar to160 arcmin(2). At this depth, the SPS detects an average of one emission-line galaxy per three fields. We present the analysis of these data and the identification of 131 low- to intermediate-red shift galaxies detected by optical emission lines. The sample contains 78 objects with emission lines that we infer to be redshifted [O II] lambda3727 emission at 0.43 C3O2). New IR spectra are reported for the 1 - 5 mum region, along with band strengths for the stronger features of carbon suboxide, carbonic acid, the ammonium and cyanate ions, polyoxymethylene, and ethylene glycol. These six materials are possible contributors to EKB surfaces, and will be of interest to observers and future missions. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Eckerd Coll, St Petersburg, FL 33733 USA. USN Acad, Annapolis, MD 21402 USA. RP Moore, MH (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM Marla.H.Moore@nasa.gov; hudsonrl@eckerd.edu; ferrante@usna.edu RI Hudson, Reggie/E-2335-2012 NR 42 TC 31 Z9 31 U1 1 U2 10 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PD JUN PY 2003 VL 92 IS 1-4 BP 291 EP 306 DI 10.1023/B:MOON.0000031946.53696.f6 PG 16 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 829OD UT WOS:000222057600026 ER PT J AU Cruikshank, DP Ore, CMD AF Cruikshank, DP Ore, CMD TI Spectral models of Kuiper Belt objects and Centaurs SO EARTH MOON AND PLANETS LA English DT Article ID CHARGED-PARTICLE IRRADIATION; OUTER SOLAR-SYSTEM; ESO LARGE PROGRAM; COMET HALE-BOPP; WATER ICE; REFLECTANCE SPECTROSCOPY; INFRARED PHOTOMETRY; OPTICAL-CONSTANTS; 5145 PHOLUS; X-RAY AB We present models of the spectral reflectances of groups of outer Solar System objects defined primarily by their colors in the spectral region 0.4 - 1.2 mum, and which have geometric albedo similar to0.04 at wavelength 0.55 mum. Our models of the groups with the strongest reflectance gradients ( reddest colors) use combinations of organic tholins. We test the hypothesis that metal-reddened igneous rock-forming minerals contribute to the red colors of Centaurs and KBOs by using the space-weathered lunar soil as one of the components of our models. We find that our models can admit the presence of moderate amounts of space-weathered (metal-reddened) minerals, but that they do not require this material to achieve the red colors of the reddest outer Solar System bodies. Our models with organic tholins are consistent with the results of other investigators. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Mountain View, CA USA. RP Cruikshank, DP (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 41 TC 17 Z9 17 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 2003 VL 92 IS 1-4 BP 315 EP 330 DI 10.1023/B:MOON.0000031948.39136.7d PG 16 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 829OD UT WOS:000222057600028 ER PT J AU Alcock, C Dave, R Giammarco, J Goldader, J Lehner, M King, SK Lee, T Wang, A Wang, SY Wen, CY Chen, WP Cook, K Marshall, S Porrata, R Byun, YI de Pater, I Rice, J Lissauer, J AF Alcock, C Dave, R Giammarco, J Goldader, J Lehner, M King, SK Lee, T Wang, A Wang, SY Wen, CY Chen, WP Cook, K Marshall, S Porrata, R Byun, YI de Pater, I Rice, J Lissauer, J TI TAOS: The Taiwanese-American Occultation Survey SO EARTH MOON AND PLANETS LA English DT Article ID KUIPER-BELT OBJECTS AB The Taiwanese - American Occultation Survey (TAOS) seeks to determine the number and size spectrum for small (similar to3 km) bodies in the Kuiper Belt. This will be accomplished by searching for the brief occultations of bright stars ( R similar to 14) by these objects. We have designed and built a special purpose photometric monitoring system for this purpose. TAOS comprises four 50 cm telescopes, each equipped with a 2048 x 2048 pixel CCD camera, in a compact array located in the central highlands of Taiwan. TAOS will monitor up to 3, 000 stars at 5 Hz. The system will go into scientific operation at the end of 2003. C1 Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. Acad Sinica, Inst Astron, Taipei 115, Taiwan. Acad Sinica, Inst Astrophys, Taipei 115, Taiwan. Natl Cent Univ, Dept Astron, Chungli 32054, Taiwan. Lawrence Livermore Natl Lab, Livermore, CA USA. Yonsei Univ Observ, Seoul, South Korea. Univ Calif Berkeley, Berkeley, CA 94720 USA. NASA, Ames Res Ctr, Mountain View, CA USA. RP Alcock, C (reprint author), Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. NR 7 TC 11 Z9 11 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PD JUN PY 2003 VL 92 IS 1-4 BP 459 EP 464 DI 10.1023/B:MOON.0000031960.82021.26 PG 6 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 829OD UT WOS:000222057600040 ER PT J AU Short, JW Rice, SD Heintz, RA Carls, MG Moles, A AF Short, JW Rice, SD Heintz, RA Carls, MG Moles, A TI Long-term effects of crude oil on developing fish: Lessons from the Exxon Valdez oil spill SO ENERGY SOURCES LA English DT Article DE crude oil; embryo toxicity; Exxon Valdez; fish habitat; polycyclic aromatic hydrocarbons; toxicity ID PRINCE-WILLIAM-SOUND; SALMON ONCORHYNCHUS-GORBUSCHA; COASTAL ENVIRONMENT; EXPOSURE; EMBRYOS; SENSITIVITY; SEDIMENTS; ALASKA; HYDROCARBONS; MORTALITY AB Habitat damage resulting from oil contamination is underestimated by acute toxicity assays. Nearshore substrates oiled by spills may become persistent pollution sources of toxic polycyclic aromatic hydrocarbons (PAH). Recent findings resulting from research following the Exxon Valdez oil spill include: ( 1) PAHs are released from oil films and droplets at progressively slower rates with an increasing molecular weight, leading to greater persistence of larger PAHs; ( 2) eggs from demersally-spawning fish species accumulate dissolved PAHs released from oiled substrates, even when the oil is heavily weathered; and (3) PAHs accumulated by embryos from aqueous concentrations of < 1 μg/L can lead to adverse sequelae appearing at random over the lifespan of an exposed cohort, probably as a result of damage during early embryogenesis. Polycyclic Aromatic Hydrocarbons (PAH) can be a slow-acting poison, and toxic effects may not manifest until long after exposure. These considerations have important policy implications regarding protection of fish natal and rearing habitats. C1 Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, NOAA, Juneau, AK USA. RP Moles, A (reprint author), 11305 Glacier Highway, Juneau, AK 99801 USA. NR 26 TC 31 Z9 31 U1 4 U2 44 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0090-8312 J9 ENERG SOURCE JI Energy Sources PD JUN PY 2003 VL 25 IS 6 BP 509 EP 517 DI 10.1080/00908310390195589 PG 9 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA 675DU UT WOS:000182678400003 ER PT J AU Dillon, JG Miller, SR Castenholz, RW AF Dillon, JG Miller, SR Castenholz, RW TI UV-acclimation responses in natural populations of cyanobacteria (Calothrix sp.) SO ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID ADAPTIVE PLASTICITY HYPOTHESIS; SOLAR ULTRAVIOLET-RADIATION; MICROSCALE ACCLIMATION; TROPICAL RHODOPHYTES; SHEATH PIGMENT; B RADIATION; ICE ALGAE; SCYTONEMIN; TERM; PHOTOACCLIMATION AB Phenotypic acclimation to changing conditions is typically thought to be beneficial to organisms in the environment. UV radiation is an important parameter affecting photosynthetic organisms in natural environments. We measured the response of photosynthetic carbon fixation in populations of cyanobacteria inhabiting a hot spring following acclimation to different UV treatments. These two very closely related populations of cyanobacteria, differing in their content of the extracellular UV-screening pigment scytonemin, were acclimated in situ under natural solar irradiance modified by filters that excluded both UVA/B, only UVB or transmitted both UVA/B. Cells from each preacclimation treatment were subsequently assayed for photosynthetic performance under all UV conditions (incubation treatment) giving a two-factor experimental design for each population. No acclimation filter treatment effects were observed even after two months under different acclimation treatments. This suggests that UV photoacclimation does not occur in either of these populations, regardless of the presence of scytonemin. By contrast, cells showed significant UV-inhibition during 1 h incubations under full sun. The population with high levels of scytonemin usually had lower rates of photosynthetic carbon fixation than the scytonemin-lacking population. However, the degree of UV inhibition, especially UVA inhibition, was higher for the cells without scytonemin pigment. These results suggest that closely related natural cyanobacterial populations respond differently to natural irradiance conditions and may be adopting different strategies of UV tolerance. C1 Univ Oregon, Dept Biol, NASA, Astrobiol Inst, Eugene, OR 97403 USA. Univ Washington, Dept Civil & Environm Engn, Seattle, WA 98195 USA. N Carolina State Univ, Dept Genet, Raleigh, NC 27695 USA. RP Castenholz, RW (reprint author), Univ Oregon, Dept Biol, NASA, Astrobiol Inst, Eugene, OR 97403 USA. NR 34 TC 18 Z9 18 U1 2 U2 10 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 1462-2912 J9 ENVIRON MICROBIOL JI Environ. Microbiol. PD JUN PY 2003 VL 5 IS 6 BP 473 EP 483 DI 10.1046/j.1462-2920.2003.00435.x PG 11 WC Microbiology SC Microbiology GA 680ZC UT WOS:000183009100004 PM 12755714 ER PT J AU Dillon, JG Castenholz, RW AF Dillon, JG Castenholz, RW TI The synthesis of the UV-screening pigment, scytonemin, and photosynthetic performance in isolates from closely related natural populations of cyanobacteria (Calothrix sp.) SO ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID SHEATH PIGMENT; RADIATION; CHROOCOCCIDIOPSIS AB Two populations of the cyanobacterium Calothrix sp. found in Yellowstone thermal spring outflows differ greatly in their contents of scytonemin, a UV-screening pigment, and in their photosynthetic carbon assimilation rates. Clonal isolates from both populations were used to investigate these phenotypic differences. Identical partial 16S rDNA sequences (similar to900 bp) suggest a very close relationship between the two Calothrix populations and indicate that environmental differences may, in part, explain the field observations. The effects of native spring water on scytonemin synthesis and photosynthesis were tested during experiments using plated cells. Results show differences in the spring water environment were at least partly responsible for the differences in scytonemin content observed in the field. Furthermore, spring water effects on photosynthetic performance suggest adaptation in these strains to their spring of origin. Controlled experiments performed using cultures grown in artificial liquid medium showed no significant difference in photosynthetic carbon uptake between strains. However, significant differences were detected in their ability to synthesize scytonemin indicating genetic differences between populations. These findings suggest that both genetic and environmental differences are responsible for the naturally occurring variation in scytonemin content and photosynthetic ability in these two closely related populations. C1 Univ Oregon, Dept Biol, Eugene, OR 97403 USA. Univ Washington, Dept Civil & Environm Engn, Seattle, WA 98195 USA. NASA, Astrobiol Inst, Eugene, OR 97403 USA. RP Castenholz, RW (reprint author), Univ Oregon, Dept Biol, Eugene, OR 97403 USA. NR 23 TC 24 Z9 26 U1 1 U2 6 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 1462-2912 J9 ENVIRON MICROBIOL JI Environ. Microbiol. PD JUN PY 2003 VL 5 IS 6 BP 484 EP 491 DI 10.1046/j.1462-2920.2003.00436.x PG 8 WC Microbiology SC Microbiology GA 680ZC UT WOS:000183009100005 PM 12755715 ER PT J AU Meise, CJ Stehlik, LL AF Meise, CJ Stehlik, LL TI Habitat use, temporal abundance variability, and diet of blue crabs from a New Jersey estuarine system SO ESTUARIES LA English DT Article ID CALLINECTES-SAPIDUS RATHBUN; DENSITY-DEPENDENT PREDATION; SOUTHERN NEW-JERSEY; TIDAL MARSH CREEK; CHESAPEAKE-BAY; POPULATION-DYNAMICS; BRACHYURAN MEGALOPAE; MUTUAL INTERFERENCE; NURSERY HABITATS; YOUNG JUVENILES AB In a long-term, spatially comprehensive beam trawl survey of the Navesink River-Sandy Hook Bay estuary, the blue crab Callinectes sapidus was one of the most abundant species. Seasonal changes in abundance were evident, with low abundances in summer followed by peak abundances in the fall, after juveniles recruited to the estuary. We saw no long-term trends in abundance during the 5 yr study. Location in the Navesink River or Sandy Hook Bay explained most of the variance in abundance within any one survey. In diet analyses, we found evidence of cannibalism in all seasons, but in the size range of crabs caught in this study (10-180 mm), we did not find a relationship between cannibalism and juvenile crab abundance. Within surveys, crabs divided into 20 mm size categories showed no size-related differences in location within the estuary or among 7 habitat types examined (algae bed, amphipod bed, beach, channel, marsh edge, mid-depth, and sandbar). Channels and sandbars tended to exhibit lower crab abundance than other habitats. Shallow habitats with and without cover were equally preferred by juvenile blue crabs, implying that the presence of structure was not critical. Spatial models of crab abundance (less than or equal to 80 mm carapace width) to environmental data were fit from several seasons of intensive sampling in the Navesink River-Sandy Hook Bay estuary between summer 1996 and spring 1998. These models indicated that fine-grained sediments, temperature, depth, and salinity were good indicators of crab abundance in spring, summer, and fall. Using these spatial models and environmental data collected in subsequent seasons (summer 1998-fall 1999), we were able to predict blue crab abundance in the river as evidenced by significant correlations between predicted and observed abundances. For the size range of crabs examined here, physical conditions may be as important as structural habitat types or cannibalism in determining habitat use in northerly estuaries. C1 US Dept Commerce, NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr,James J Howard Marie Sci Lab, Highlands, NJ 07732 USA. RP Meise, CJ (reprint author), US Dept Commerce, NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr,James J Howard Marie Sci Lab, Highlands, NJ 07732 USA. NR 76 TC 16 Z9 17 U1 1 U2 14 PU ESTUARINE RES FEDERATION PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 USA SN 0160-8347 J9 ESTUARIES JI Estuaries PD JUN PY 2003 VL 26 IS 3 BP 731 EP 745 DI 10.1007/BF02711984 PG 15 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 712NN UT WOS:000184803900010 ER PT J AU Driver, DM AF Driver, DM TI Application of oil-film interferometry skin-friction measurement to large wind tunnels SO EXPERIMENTS IN FLUIDS LA English DT Article AB The oil-film interferometry skin-friction technique is described and applied to flows in some of the NASA Ames large wind tunnel facilities. Various schemes for applying the technique are discussed. Results are shown for tests in several wind tunnels that illustrate the oil film's ability to measure a variety of flow features such as shock waves, separation, and three-dimensional flow. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Driver, DM (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 10 TC 17 Z9 21 U1 1 U2 9 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0723-4864 J9 EXP FLUIDS JI Exp. Fluids PD JUN PY 2003 VL 34 IS 6 BP 717 EP 725 DI 10.1007/s00348-003-0613-1 PG 9 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 698TT UT WOS:000184015400007 ER PT J AU Kazanas, D Nicolaidis, A AF Kazanas, D Nicolaidis, A TI Cosmic rays and large extra dimensions SO GENERAL RELATIVITY AND GRAVITATION LA English DT Letter DE graviton production; cosmic ray; Kaluza-Klein theory ID TEV; CONSTRAINTS; MILLIMETER; SPECTRUM AB We have proposed that the cosmic ray spectrum "knee", the steepening of the cosmic ray spectrum at energy E greater than or similar to T 10(15.5) eV, is due to "new physics", namely new interactions at TeV cm energies which produce particles undetected by the experimental apparatus. In this letter we examine specifically the possibility that this interaction is low scale gravity. We consider that the graviton propagates, besides the usual four dimensions, into an additional delta, compactified, large dimensions and we estimate the graviton production in pp collisions in the high energy approximation where graviton emission is factorized. We find that the cross section for graviton production rises as fast as (roots/M-f)(2+delta), where M-f is the fundamental scale of gravity in 4 + delta dimensions, and that the distribution of radiating a fraction y of the initial particle's energy into gravitational energy ( which goes undetected) behaves as deltay(delta-1). The missing energy leads to an underestimate of the true energy and generates a break in the inferred cosmic ray spectrum (the "knee"). By fitting the cosmic ray spectrum data we deduce that the favorite values for the parameters of the theory are M-f similar to 8 TeV and delta = 4. C1 NASA, LHEA, GSFC, Greenbelt, MD 20771 USA. Univ Thessaloniki, Dept Theoret Phys, GR-54006 Thessaloniki, Greece. RP Kazanas, D (reprint author), NASA, LHEA, GSFC, Code 661, Greenbelt, MD 20771 USA. NR 27 TC 32 Z9 33 U1 0 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0001-7701 J9 GEN RELAT GRAVIT JI Gen. Relativ. Gravit. PD JUN PY 2003 VL 35 IS 6 BP 1117 EP 1123 DI 10.1023/A:1024077103557 PG 7 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 685GA UT WOS:000183252200010 ER PT J AU Chabot, NL Agee, CB AF Chabot, NL Agee, CB TI Core formation in the Earth and Moon: New experimental constraints from V, Cr, and Mn SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID SILICATE PARTITION-COEFFICIENTS; DEEP MAGMA OCEAN; FE-NI-S; HIGH-PRESSURE; SIDEROPHILE ELEMENTS; GIANT IMPACT; MELT COMPOSITION; ACCRETING EARTH; OXYGEN FUGACITY; METALLIC LIQUID AB The mantles of the Earth and Moon are similarly depleted in V, Cr, and Mn relative to the concentrations of these elements in chondritic meteorites. The similar depletions have been used as evidence that the Moon inherited its mantle from the Earth after a giant impact event. We have conducted liquid metal-liquid silicate partitioning experiments for V, Cr, and Mn from 3 to 14 GPa and 1723 to 2573 K to understand the behavior of these elements during planetary core formation. Our experiments have included systematic studies of the effects of temperature, silicate composition, metallic S-content, metallic C-content, and pressure. Temperature has a significant effect on the partitioning of V, Cr, Mn, with all three elements increasing their partitioning into the metallic liquid with increasing temperature. In contrast, pressure is not observed to affect the partitioning behavior. The experimental results show the partitioning of Cr and Mn are hardly dependent on the silicate composition, whereas V partitions more strongly into depolymerized silicate melts. The addition of either S or C to the metallic liquid causes increased metal-silicate partition coefficients for all three elements. Parameterizing and applying the experimental data, we find that the Earth's mantle depletions of V, Cr, and possibly Mn can be explained by core formation in a high-temperature magma ocean under oxygen fugacity conditions about two log units below the iron-wustite buffer, though the depletion of Mn may be due entirely to its volatility. However, more oxidizing conditions proposed in recent core formation models for the Earth cannot account for any of the depletions. Additionally, because we observe no pressure effect on the partitioning behavior, the data do not require the mantle of the Moon to be derived from the Earth's mantle, although this is not ruled out. All that is required to create depletions of V, Cr, and Mn in a mantle is a planetary body that is hot enough and reducing enough during its core formation. Such conditions could have existed on the Moon-forming impactor. Copyright (C) 2003 Elsevier Science Ltd. C1 Case Western Reserve Univ, Dept Geol Sci, Cleveland, OH 44106 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Chabot, NL (reprint author), Case Western Reserve Univ, Dept Geol Sci, 112 A W Smith Bldg, Cleveland, OH 44106 USA. RI Chabot, Nancy/F-5384-2015 OI Chabot, Nancy/0000-0001-8628-3176 NR 51 TC 80 Z9 81 U1 1 U2 18 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 2003 VL 67 IS 11 BP 2077 EP 2091 DI 10.1016/S0016-7037(02)01272-3 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 679ZM UT WOS:000182951900009 ER PT J AU Thompson, CM Smith, JG Connell, JW AF Thompson, CM Smith, JG Connell, JW TI Polyimides prepared from 4,4 '-(2-diphenylphosphinyl-1,4-phenylenedioxy)diphthalic anhydride for potential space applications SO HIGH PERFORMANCE POLYMERS LA English DT Article DE polyimides; space durable polymers; atomic oxygen resistant polymers; 4,4 '-(2-diphenylphosphinyl-1,4-phenylenedioxy)diphthalic anhydride ID POLY(ARYLENE ETHER HETEROCYCLE)S; OXIDE-CONTAINING POLYIMIDES; OXYGEN PLASMA; FILMS AB As part of an ongoing materials development activity to produce high performance polymers that are space environmentally stable, phosphine oxide containing polyimides were prepared by reacting a novel aromatic dianhydride, 4,4-(2-diphenylphosphinyl-1,4-phenylenedioxy)diphthalic anhydride 3, with aromatic diamines. The dianhydride was prepared from 2,5-dihydroxyphenyldiphenylphosphine oxide in three steps in relatively good yield. In general, the polyimides exhibited physical and mechanical properties comparable to other wholly aromatic polyimides. Depending upon the diamine, nearly all of the polyimides formed near colorless to yellow films. The polyimides were amorphous and in most cases soluble in polar aprotic solvents. However, one polymer film prepared using 1,4-phenylenediamine exhibited some degree of ordering when prepared by chemical imidization. The chemistry, physical and mechanical properties of the polymers are discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Thompson, CM (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 16 TC 11 Z9 14 U1 2 U2 4 PU SAGE PUBLICATIONS LTD PI LONDON PA 6 BONHILL STREET, LONDON EC2A 4PU, ENGLAND SN 0954-0083 J9 HIGH PERFORM POLYM JI High Perform. Polym. PD JUN PY 2003 VL 15 IS 2 BP 181 EP 195 DI 10.1177/0954008303015002003 PG 15 WC Polymer Science SC Polymer Science GA 687RD UT WOS:000183389700003 ER PT J AU Hobbs, A Williamson, A AF Hobbs, A Williamson, A TI Associations between errors and contributing factors in aircraft maintenance SO HUMAN FACTORS LA English DT Article ID OCCUPATIONAL ACCIDENTS; CLASSIFICATION-SYSTEM; SAFETY; WORK; INVOLVEMENT; PERFORMANCE; VIOLATIONS; BEHAVIOR; OUTCOMES AB In recent years cognitive error models have provided insights into the unsafe acts that lead to many accidents in safety-critical environments. Most models of accident causation are based on the notion that human errors occur in the context of contributing factors. However, there is a lack of published information on possible links between specific errors and contributing factors. A total of 619 safety occurrences involving aircraft maintenance were reported using a self-completed questionnaire. Of these occurrences, 96% were related to the actions of maintenance personnel. The types of errors that were involved, and the contributing factors associated with those actions, were determined. Each type of error was associated with a particular set of contributing factors and with specific occurrence outcomes. Among the associations were links between memory lapses and fatigue and between rule violations and time pressure. Potential applications of this research include assisting with the design of accident prevention strategies, the estimation of human error probabilities, and the monitoring of organizational safety performance. C1 Australian Transport Safety Bur, Canberra, ACT, Australia. Injury Risk Management Res Ctr, Sydney, NSW, Australia. RP San Jose State Univ Fdn, NASA, Ames Res Ctr, Mail Stop 262-4, Moffett Field, CA 94035 USA. EM ahobbs@mail.arc.nasa.gov NR 64 TC 37 Z9 38 U1 4 U2 17 PU SAGE PUBLICATIONS INC PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 USA SN 0018-7208 EI 1547-8181 J9 HUM FACTORS JI Hum. Factors PD SUM PY 2003 VL 45 IS 2 BP 186 EP 201 DI 10.1518/hfes.45.2.186.27244 PG 16 WC Behavioral Sciences; Engineering, Industrial; Ergonomics; Psychology, Applied; Psychology SC Behavioral Sciences; Engineering; Psychology GA 718MY UT WOS:000185151600002 PM 14529193 ER PT J AU Zahnle, K Schenk, P Levison, H Dones, L AF Zahnle, K Schenk, P Levison, H Dones, L TI Cratering rates in the outer Solar System SO ICARUS LA English DT Article ID JUPITER-FAMILY COMETS; SHORT-PERIOD COMETS; KUIPER-BELT OBJECTS; SHOEMAKER-LEVY 9; SIZE DISTRIBUTION; ECLIPTIC COMETS; LONG-PERIOD; MAGNITUDE DISTRIBUTION; TROJAN ASTEROIDS; CARBON-MONOXIDE AB This paper is a compilation by table, graph, and equation of impact cratering rates from Jupiter to Pluto. We use several independent constraints on the number of ecliptic comets. Together they imply that the impact rate on Jupiter by 1.5-km-diameter comets is currently N(d > 1.5 km) = 0.005-(+0/006)(0.003) per annum. Other kinds of impactors are currently unimportant on most worlds at most sizes. The size-number distribution of impactors smaller than 20 km is inferred from size-number distributions of impact craters on Europa, Ganymede, and Triton; while the size-number distribution of impacting bodies larger than 50 km is equated to the size-number distribution of Kuiper Belt objects. The gap is bridged by interpolation. It is notable that small craters on Jupiter's moons indicate a pronounced paucity of small impactors, while small craters on Triton imply a collisional population rich in small bodies. However it is unclear whether the craters on Triton are of heliocentric or planetocentric origin. We therefore consider two cases for Saturn and beyond: a Case A in which the size-number distribution is like that inferred at Jupiter, and a Case B in which small objects obey a more nearly collisional distribution. Known craters on saturnian and uranian satellites are consistent with either case, although surface ages are much younger in Case B, especially at Saturn and Uranus. At Neptune and especially at Saturn our cratering rates are much higher than rates estimated by Shoemaker and colleagues, presumably because Shoemaker's estimates mostly predate discovery of the Kuiper Belt. We also estimate collisional disruption rates of moons and compare these to estimates in the literature. (C) 2003 Elsevier Science (USA). All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Lunar & Planetary Inst, Houston, TX 77058 USA. SW Res Inst, Boulder, CO 80302 USA. RP Zahnle, K (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. EM kzahnle@mail.arc.nasa.gov RI Levison, Harold/C-6061-2013 OI Levison, Harold/0000-0001-5847-8099 NR 99 TC 239 Z9 240 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 J9 ICARUS JI Icarus PD JUN PY 2003 VL 163 IS 2 BP 263 EP 289 DI 10.1016/S0019-1035(03)00048-4 PG 27 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 694VN UT WOS:000183796000001 ER PT J AU de Pater, I Butler, BJ Green, DA Strom, R Millan, R Klein, MJ Bird, MK Funke, O Neidhofer, J Maddalena, R Sault, RJ Kesteven, M Smits, DP Hunstead, R AF de Pater, I Butler, BJ Green, DA Strom, R Millan, R Klein, MJ Bird, MK Funke, O Neidhofer, J Maddalena, R Sault, RJ Kesteven, M Smits, DP Hunstead, R TI Jupiter's radio spectrum from 74 MHz up to 8 GHz SO ICARUS LA English DT Article DE Jupiter; magnetosphere; radio observations ID COMET-P SHOEMAKER-LEVY-9; ELECTRON-RADIATION BELT; LONG-TERM VARIATIONS; SYNCHROTRON-RADIATION; FLUX-DENSITY; ENERGETIC ELECTRONS; DIFFUSION-MODELS; EMISSION; CM; IMPACTS AB We carried out a brief campaign in September 1998 to determine Jupiter's radio spectrum at frequencies spanning a range from 74 MHz up to 8 GHz. Eleven different telescopes were used in this effort, each uniquely suited to observe at a particular frequency. We find that Jupiter's spectrum is basically flat shortwards of 1-2 GHz, and drops off steeply at frequencies greater than 2 GHz. We compared the 1998 spectrum with a spectrum (330 MHz-8 GHz) obtained in June 1994, and report a large difference in spectral shape, being most pronounced at the lowest frequencies. The difference seems to be linear with log(nu), with the largest deviations at the lowest frequencies (nu). We have compared our spectra with calculations of Jupiter's synchrotron radiation using several published models. The spectral shape is determined by the energy-dependent spatial distribution of the electrons in Jupiter's magnetic field, which in turn is determined by the detailed diffusion process across L-shells and in pitch angle, as well as energy-dependent particle losses. The spectral shape observed in September 1998 can be matched well if the electron energy spectrum at L = 6 is modeled by a double power law E-a (1 + (E/E-0))(-b), with a = 0.4, b = 3, E-0 = 100 MeV, and a lifetime against local losses To = 6 X 107 S. In June 1994 the observations can be matched equally well with two different sets of parameters: (1) a = 0.6, b = 3, E-0 = 100 MeV, tau(0) = 6 x 10(7) s, or (2) a = 0.4, b = 3, E-0 = 100 MeV, tau(0) = 8.6 x 10(6) s. We attribute the large variation in spectral shape between 1994 and 1998 to pitch angle scattering, coulomb scattering and/or energy degradation by dust in Jupiter's inner radiation belts. (C) 2003 Elsevier Science (USA). All rights reserved. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Earth & Planetary Sci, Berkeley, CA 94720 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Univ Cambridge, Cavendish Lab, Mullard Radio Astron Observ, Cambridge CB3 0HE, England. Univ Amsterdam, Inst Astron, Amsterdam, Netherlands. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Bonn, Inst Radioastron, D-53121 Bonn, Germany. Max Planck Inst Radioastron, D-53121 Bonn, Germany. Natl Radio Astron Observ, Green Bank, WV 24944 USA. CSIRO, Epping, NSW 2121, Australia. Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. RP de Pater, I (reprint author), Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA. RI Green, David/E-9609-2010 OI Green, David/0000-0003-3189-9998 NR 55 TC 24 Z9 24 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 2003 VL 163 IS 2 BP 434 EP 448 DI 10.1016/S0019-1035(03)00067-8 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 694VN UT WOS:000183796000012 ER PT J AU Rubincam, DP AF Rubincam, DP TI Polar wander on Triton and Pluto due to volatile migration SO ICARUS LA English DT Article ID GRAVITY MODEL; MARS; INSOLATION; OBLIQUITY; NEPTUNE; CYCLE; EARTH AB Polar wander may occur on Triton and Pluto because of volatile migration. Triton, with its low obliquity, can theoretically sublimate volatiles (mostly nitrogen) at the rate of similar to10(13) kg year(-1) from the equatorial regions and deposit them at the poles. Assuming Triton to be rigid on the sublimation timescale, after similar to10(5) years the polar caps would become large enough to cancel the rotational flattening, with a total mass equivalent to a global layer similar to120-250 m in depth. At this point the pole wanders about the tidal bulge axis, which is the line joining Triton and Neptune. Rotation about the bulge axis might be expected to disturb the leading side/trailing side cratering statistics. Because no such disturbance is observed, it may be that Triton's surface volatile inventory is too low to permit wander. On the other hand, its mantle viscosity might be low, so that any uncompensated cap load might be expected to wander toward the tidal bulge axis. In this case, the axis of wander passes through the equator from the leading side to the trailing side; rotation about this wander axis would not disturb the cratering statistics. Low-viscosity polar wander may explain the bright southern hemisphere: this is the pole which is wandering toward the sub-Neptune point. In any case the "permanent" polar caps may be geologically very young. Polar wander may possibly take place on Pluto, due to its obliquity oscillations and perihelion-pole geometry. However, Pluto is probably not experiencing any wander at present. The Sun has been shining strongly on the poles over the last half of the obliquity cycle, so that volatiles should migrate to the equator, stabilizing the planet against wander. Spacecraft missions to Triton and Pluto which measure the dynamical flattening could give information about the accumulation of volatiles at the poles. Such information is best obtained by measuring gravity and topography from orbiters, as was done for Mars with the highly successful Mars Global Surveyor. (C) 2003 Elsevier Science (USA). All rights reserved. C1 NASA, Goddard Space Flight Ctr, Geodynam Branch, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Rubincam, DP (reprint author), NASA, Goddard Space Flight Ctr, Geodynam Branch, Terr Phys Lab, Code 921,Bldg 33,Room G308, Greenbelt, MD 20771 USA. EM David.P.Rubincam@nasa.gov RI Rubincam, David/D-2918-2012 NR 39 TC 12 Z9 12 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 2003 VL 163 IS 2 BP 469 EP 478 DI 10.1016/S0019-1035(03)00080-0 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 694VN UT WOS:000183796000015 ER PT J AU Burleigh, S Hooke, A Torgerson, L Fall, K Cerf, V Durst, B Scott, K Weiss, H AF Burleigh, S Hooke, A Torgerson, L Fall, K Cerf, V Durst, B Scott, K Weiss, H TI Delay-tolerant networking: An approach to interplanetary Internet SO IEEE COMMUNICATIONS MAGAZINE LA English DT Article C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Intel Corp, Berkeley Res Ctr, Santa Clara, CA 95051 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Network Res Grp, Berkeley, CA 94720 USA. Mitre Corp, Informat Syst & Technol Div, Networking & Commun Engn Dept, Bedford, MA 01730 USA. Mitre Corp, Ctr Innovat Comp & Informat, Bedford, MA 01730 USA. Sparta Syst Inc, Laguna Hills, CA 92653 USA. RP Burleigh, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 372 Z9 410 U1 3 U2 17 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0163-6804 J9 IEEE COMMUN MAG JI IEEE Commun. Mag. PD JUN PY 2003 VL 41 IS 6 BP 128 EP 136 DI 10.1109/MCOM.2003.1204759 PG 9 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 684PY UT WOS:000183216800019 ER PT J AU Skalare, A McGrath, WR Bumble, B LeDuc, HG AF Skalare, A McGrath, WR Bumble, B LeDuc, HG TI Speed measurements of diffusion-cooled tantalum bolometers SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT Applied Superconductivity Conference CY AUG 04-09, 2002 CL HOUSTON, TEXAS SP Apple, Argonne Natl Lab, Florida State Univ, Ctr Adv Power Syst, Cingular Wireless, Council SuperCond Amer Competit, Hewlett Packard Co, Houston Adv Res Ctr, IEEE CSC Council Supercond, IISSC, Marimon, Naval Res Lab, Oak Ridge Natl Lab, Univ Houston, Texas Ctr Supercond & Adv Mat, US DOE, Div High Energy Phys, Univ Houston, Cullen Coll Engn, Univ Houston, Coll Nat Sci & Math, Univ Houston, Div Res, Wah Chang DE bolometer; mixer; superconductor; tantalum ID HOT-ELECTRON BOLOMETER; MIXERS; NOISE AB Thin tantalum films were deposited on silicon wafers using a niobium seed layer to promote alpha-phase growth. These films were patterned into submicrometer size diffusion-cooled bolometers with superconducting transition temperatures of up to 2.35 K and a transition width of about 200 mK. The thermal relaxation times of the devices were determined by measuring the device impedance as a function of frequency and by fitting a theoretical model to the data. Measured relaxation times at low bias voltages range from 0.75 GHz for a 400-nm long device to 6 GHz for a 100-nm device, excluding electrothermal feedback. This should allow sufficiently high instantaneous bandwidths. for most low-noise mixer applications in astrophysics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Skalare, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 2 Z9 2 U1 0 U2 3 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 2003 VL 13 IS 2 BP 160 EP 163 DI 10.1109/TASC.2003.813670 PN 1 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 702UB UT WOS:000184241700021 ER PT J AU Karasik, BS Delaet, B McGrath, WR Wei, J Gershenson, ME Sergeev, AV AF Karasik, BS Delaet, B McGrath, WR Wei, J Gershenson, ME Sergeev, AV TI Experimental study of superconducting hot-electron sensors for submm astronomy SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT Applied Superconductivity Conference CY AUG 04-09, 2002 CL HOUSTON, TEXAS SP Apple, Argonne Natl Lab, Florida State Univ, Ctr Adv Power Syst, Cingular Wireless, Council SuperCond Amer Competit, Hewlett Packard Co, Houston Adv Res Ctr, IEEE CSC Council Supercond, IISSC, Marimon, Naval Res Lab, Oak Ridge Natl Lab, Univ Houston, Texas Ctr Supercond & Adv Mat, US DOE, Div High Energy Phys, Univ Houston, Cullen Coll Engn, Univ Houston, Coll Nat Sci & Math, Univ Houston, Div Res, Wah Chang DE bolometers; electron-phonon coupling; photon counters; superconducting devices ID SINGLE-PHOTON DETECTOR; MIXER; BOLOMETER; RANGE AB Relaxation, noise, and spectral properties of micron-size hot-electron sensors made from thin Ti film are studied. Due to the small heat capacity of electrons, the devices are sensitive to single quanta of submm radiation. The sensors can be used for both hot-electron direct detectors (HEDD) and hot-electron photon-counters (HEPC) depending whether electron-phonon relaxation or electron outdiffusion is a dominating cooling mechanism. In an HEDD, the diffusion is blocked by Andreev contacts and the cooling rate is determined by the electron-phonon relaxation. The electron-phonon time in disordered films is long (tau(e-ph) approximate to 0.16 x T-4 mus) providing an NEP approximate to 10(-19) W/rootHz at 0.3 K and NEP approximate to 10(-20) W/rootHz at 0.1 K. The output noise in micron-size bridges follows the predictions of the hot-electron model. In the diffusion mode, the relaxation time of 3 ns has been measured in a 3 mum-long device. Smaller size HEPC's would be able to operate with the spectral resolution of 300 GHz at 0.3 K and 100 GHz at 0.1 K and with the photon counting rate in the GHz range. The spectral response of a prototype antenna-coupled Nb HEDD device has been measured and shown to be flat over the range 250-900 GHz. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Rutgers State Univ, Piscataway, NJ 08854 USA. Wayne State Univ, Detroit, MI 48202 USA. RP Karasik, BS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Wei, Jian/B-2137-2014; Karasik, Boris/C-5918-2011 OI Wei, Jian/0000-0002-8831-6418; NR 17 TC 13 Z9 13 U1 0 U2 5 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 2003 VL 13 IS 2 BP 188 EP 191 DI 10.1109/TASC.2003.813677 PN 1 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 702UB UT WOS:000184241700028 ER PT J AU Claycomb, JR Brazdeikis, A Le, M Yarbrough, RA Gogoshin, G Miller, JH AF Claycomb, JR Brazdeikis, A Le, M Yarbrough, RA Gogoshin, G Miller, JH TI Nondestructive testing of PEM fuel cells SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT Applied Superconductivity Conference CY AUG 04-09, 2002 CL HOUSTON, TEXAS SP Apple, Argonne Natl Lab, Florida State Univ, Ctr Adv Power Syst, Cingular Wireless, Council SuperCond Amer Competit, Hewlett Packard Co, Houston Adv Res Ctr, IEEE CSC Council Supercond, IISSC, Marimon, Naval Res Lab, Oak Ridge Natl Lab, Univ Houston, Texas Ctr Supercond & Adv Mat, US DOE, Div High Energy Phys, Univ Houston, Cullen Coll Engn, Univ Houston, Coll Nat Sci & Math, Univ Houston, Div Res, Wah Chang DE electrochemical noise; magnetic imaging; nondestructive testing; PEM fuel cells; SQUIDs ID SQUID MAGNETOMETRY AB We report on electric and magnetic Nondestructive Testing (NDT) of Proton Exchange Membrane (PEM) fuel cells. Fuel cells are electrochemical devices that convert hydrogen and oxygen gas into water, heat and useable electricity. Fuel cell membrane health can affect the cells overall performance and lifetime. We have explored several NDT techniques employing highly sensitive HTS and ITS SQUID and fluxgate magnetometers. Magnetic fields generated by electrochemical currents flowing in the fuel cell are studied in the spatial, time and frequency domain under various operating conditions. Frequency domain electric and magnetic signals are compared under extreme conditions and membrane failure. C1 Univ Houston, Dept Phys, Houston, TX 77204 USA. Univ Houston, TcSAM, Houston, TX 77204 USA. NASA, Lyndon B Johnson Space Ctr, Energy Syst Div, Houston, TX 77058 USA. RP Claycomb, JR (reprint author), Univ Houston, Dept Phys, Houston, TX 77204 USA. RI Brazdeikis, Audrius/H-3837-2015 OI Brazdeikis, Audrius/0000-0001-9536-1586 NR 6 TC 11 Z9 11 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 2003 VL 13 IS 2 BP 211 EP 214 DI 10.1109/TASC.2003.813687 PN 1 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 702UB UT WOS:000184241700034 ER PT J AU Tong, CYE Blundell, R Megerian, KG Stern, JA LeDuc, HG AF Tong, CYE Blundell, R Megerian, KG Stern, JA LeDuc, HG TI A 650 GHz fixed-tuned waveguide SIS distributed mixer with no integrated tuning circuit SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT Applied Superconductivity Conference CY AUG 04-09, 2002 CL HOUSTON, TEXAS SP Apple, Argonne Natl Lab, Florida State Univ, Ctr Adv Power Syst, Cingular Wireless, Council SuperCond Amer Competit, Hewlett Packard Co, Houston Adv Res Ctr, IEEE CSC Council Supercond, IISSC, Marimon, Naval Res Lab, Oak Ridge Natl Lab, Univ Houston, Texas Ctr Supercond & Adv Mat, US DOE, Div High Energy Phys, Univ Houston, Cullen Coll Engn, Univ Houston, Coll Nat Sci & Math, Univ Houston, Div Res, Wah Chang DE distributed mixing; integrated tuning network; resonant mixer; SIS devices ID LINE AB A Superconductor-Insulator-Superconductor (SIS) distributed mixer with no integrated tuning circuit has been designed for use in a fixed-tuned waveguide mixer block. This mixer employs two half-wave SIS resonators connected in series across the feed point of the waveguide circuit. By selecting appropriate dimensions for the resonators, we can obtain proper impedance matching over a reasonable input bandwidth. Since there is no lossy thin film microstrip line in front of the SIS junction, efficient power transfer from the waveguide feed to the mixer element can be achieved. A receiver noise temperature of 185 K at 650 GHz has been measured with a dual 0.33 x 16.8 mum SIS resonator. The noise temperature remains below 300 K over an input bandwidth of about 10%. This design can be used at much higher frequency where the loss of tuning circuit becomes significant. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tong, CYE (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Tong, Edward/0000-0002-7736-4203 NR 6 TC 5 Z9 5 U1 0 U2 1 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 2003 VL 13 IS 2 BP 680 EP 683 DI 10.1109/TASC.2003.813996 PN 1 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 702UB UT WOS:000184241700149 ER PT J AU Stevenson, TR Hsieh, WT Li, MJ Rhee, KW Schoelkopf, RJ Stahle, CM Teufel, JD AF Stevenson, TR Hsieh, WT Li, MJ Rhee, KW Schoelkopf, RJ Stahle, CM Teufel, JD TI Fabrication of tunnel junctions for direct detector arrays with single-electron transistor readout using electron-beam lithography SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT Applied Superconductivity Conference CY AUG 04-09, 2002 CL HOUSTON, TEXAS SP Apple, Argonne Natl Lab, Florida State Univ, Ctr Adv Power Syst, Cingular Wireless, Council SuperCond Amer Competit, Hewlett Packard Co, Houston Adv Res Ctr, IEEE CSC Council Supercond, IISSC, Marimon, Naval Res Lab, Oak Ridge Natl Lab, Univ Houston, Texas Ctr Supercond & Adv Mat, US DOE, Div High Energy Phys, Univ Houston, Cullen Coll Engn, Univ Houston, Coll Nat Sci & Math, Univ Houston, Div Res, Wah Chang DE deep ultraviolet; electron-beam lithography; PMMA/copolymer; single electron transistor; SQUID ID RESISTS AB This paper describes the fabrication of small aluminum tunnel junctions for applications in astronomy. Antenna-coupled superconducting tunnel junctions with integrated single-electron transistor readout have the potential for photon-counting sensitivity at sub-mm wavelengths. The junctions for the detector and single-electron transistor can be made with electron-beam lithography and a standard self-aligned double-angle deposition process. However, high yield and uniformity of the junctions is required for large-format detector arrays. This paper describes how measurement and modification of the sensitivity ratio in the resist bilayer was used to, greatly improve the reliability of forming devices with uniform, sub-micron size, low-leakage junctions. C1 NASA, Goddard Space Flight Ctr, Detector Syst Branch, Greenbelt, MD 20771 USA. Raytheon ITSS, Lanham, MD 20703 USA. USN, Res Lab, Washington, DC 20375 USA. Yale Univ, Dept Appl Phys, New Haven, CT 06520 USA. RP Stevenson, TR (reprint author), NASA, Goddard Space Flight Ctr, Detector Syst Branch, Code 553, Greenbelt, MD 20771 USA. RI Teufel, John/A-8898-2010; Schoelkopf, Robert/J-8178-2012 OI Teufel, John/0000-0002-1873-9941; NR 17 TC 1 Z9 1 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 2003 VL 13 IS 2 BP 1139 EP 1142 DI 10.1109/TASC.2003.814175 PN 1 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 702UB UT WOS:000184241700265 ER PT J AU Demko, JA Lue, JW Gouge, MJ Lindsay, D Roden, M Willen, D Daumling, M Fesmire, JE Augustynowicz, SD AF Demko, JA Lue, JW Gouge, MJ Lindsay, D Roden, M Willen, D Daumling, M Fesmire, JE Augustynowicz, SD TI Cryostat vacuum thermal considerations for HTS power transmission cable systems SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT Applied Superconductivity Conference CY AUG 04-09, 2002 CL HOUSTON, TEXAS SP Apple, Argonne Natl Lab, Florida State Univ, Ctr Adv Power Syst, Cingular Wireless, Council SuperCond Amer Competit, Hewlett Packard Co, Houston Adv Res Ctr, IEEE CSC Council Supercond, IISSC, Marimon, Naval Res Lab, Oak Ridge Natl Lab, Univ Houston, Texas Ctr Supercond & Adv Mat, US DOE, Div High Energy Phys, Univ Houston, Cullen Coll Engn, Univ Houston, Coll Nat Sci & Math, Univ Houston, Div Res, Wah Chang DE cryogenic; high-temperature superconductivity; power transmission lines ID LOSSES AB The use of high-temperature superconducting (HTS) materials for power transmission cable applications is being realized in several utility demonstration projects. Both room-temperature and cold-dielectric cable systems rely on a vacuum cryostat to keep the ambient thermal loads it a minimum. For long-term installations, operating 30 years or longer, the thermal-insulating vacuum pressure may increase in sections of a long length installation. Even if only a small section of the total length of the HTS cable system is affected, localized heating of the cable may reduce the performance of the HTS cable system. A study is presented of the effects of degraded vacuum levels on the operation of HTS cables for different cryogenic thermal insulation systems. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Southwire Co, Carrollton, GA 30119 USA. NASA, Kennedy Space Ctr, Cryogen Test Lab, Kennedy Space Ctr, FL 32899 USA. NASA, Kennedy Space Ctr, Dynacs Inc, Kennedy Space Ctr, FL 32899 USA. RP Demko, JA (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 6 TC 8 Z9 9 U1 0 U2 1 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 2003 VL 13 IS 2 BP 1930 EP 1933 DI 10.1109/TASC.2003.812956 PN 2 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 702UD UT WOS:000184241900177 ER PT J AU Wilson, TL AF Wilson, TL TI A high-temperature superconductor energy-momentum control system for small satellites SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT Applied Superconductivity Conference CY AUG 04-09, 2002 CL HOUSTON, TEXAS SP Apple, Argonne Natl Lab, Florida State Univ, Ctr Adv Power Syst, Cingular Wireless, Council SuperCond Amer Competit, Hewlett Packard Co, Houston Adv Res Ctr, IEEE CSC Council Supercond, IISSC, Marimon, Naval Res Lab, Oak Ridge Natl Lab, Univ Houston, Texas Ctr Supercond & Adv Mat, US DOE, Div High Energy Phys, Univ Houston, Cullen Coll Engn, Univ Houston, Coll Nat Sci & Math, Univ Houston, Div Res, Wah Chang DE attitude control; energy storage; magnetic bearings; momentum management ID BEARINGS AB A method for angular momentum management in flywheel energy storage systems that employ superconducting bearings for spacecraft attitude control is presented. Success with high-temperature superconductor momentum wheels as practical energy storage systems has led to increased interest in their dual function for providing electrical power as well as attitude control of small satellites. The physics of angular momentum management is used to quantify how superconductor magnetic bearing flywheels as electro-mechanical devices serve as both energy storage and angular momentum storage systems within an end-to-end architecture. The result is a compound energy-momentum attitude and electrical power control system for satellites. C1 NASA, Lyndon B Johnson Space Ctr, Space & Life Sci Directorate, Astromat Res & Explorat Sci Off, Houston, TX 77058 USA. RP Wilson, TL (reprint author), NASA, Lyndon B Johnson Space Ctr, Space & Life Sci Directorate, Astromat Res & Explorat Sci Off, Houston, TX 77058 USA. NR 15 TC 6 Z9 10 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 2003 VL 13 IS 2 BP 2287 EP 2290 DI 10.1109/TASC.2003.813078 PN 2 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 702UD UT WOS:000184241900264 ER PT J AU Soulen, RJ Claassen, JH Osofsky, MS Trotter, G Woods, GT Ovchinnikov, YN Kresen, V Tralshawala, N AF Soulen, RJ Claassen, JH Osofsky, MS Trotter, G Woods, GT Ovchinnikov, YN Kresen, V Tralshawala, N TI Characterization of the interface between a normal metal and a superconductor using magnetic screening SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT Applied Superconductivity Conference CY AUG 04-09, 2002 CL HOUSTON, TEXAS SP Apple, Argonne Natl Lab, Florida State Univ, Ctr Adv Power Syst, Cingular Wireless, Council SuperCond Amer Competit, Hewlett Packard Co, Houston Adv Res Ctr, IEEE CSC Council Supercond, IISSC, Marimon, Naval Res Lab, Oak Ridge Natl Lab, Univ Houston, Texas Ctr Supercond & Adv Mat, US DOE, Div High Energy Phys, Univ Houston, Cullen Coll Engn, Univ Houston, Coll Nat Sci & Math, Univ Houston, Div Res, Wah Chang DE interface; magnetic screening; proximity effect; superconductivity AB We have predicted the behavior of magnetic screening of N/I/S trilayers as a function of a single parameter W that parameterizes the discontinuity of the order parameter at the interface. We have compared these calculations with experimental measurements of the temperature (10 K to 1.5 K) dependence of the magnetic screening for several Nb/NbO/Al trilayers and excellent agreement between the predictions and measurements is observed. This agreement provides further understanding of the proximity effect when characterizing the N/S interface in many devices. C1 USN, Res Lab, Washington, DC 20375 USA. Natl Inst Stand & Technol, Opt Tech Div, Gaithersburg, MD 20899 USA. Russian Acad Sci, LD Landau Theoret Phys Inst, Moscow 117333, Russia. Lawrence Berkeley Lab, Berkeley, CA USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Soulen, RJ (reprint author), USN, Res Lab, Washington, DC 20375 USA. RI Osofsky, Michael/A-1050-2010 NR 7 TC 0 Z9 0 U1 0 U2 3 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 2003 VL 13 IS 2 BP 2838 EP 2841 DI 10.1109/TASC.2003.812024 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 702UH UT WOS:000184242400102 ER PT J AU Simon, MK AF Simon, MK TI Multiple-bit differential detection of offset QPSK SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article; Proceedings Paper CT IEEE International Conference on Communications (ICC) CY MAY 11-15, 2003 CL ANCHORAGE, ALASKA SP IEEE Commun Soc, AT&T Alascom, Hotel Captain Cook, GCI, New Horizons, PanAmSat, SES Americom, Tellabs, Univ Alaska Anchorage DE differential detection; error probability performance; offset quadrature phase-shift keying (QPSK) ID COMMUNICATION; DIVERSITY; BINARY; MPSK AB Analogous to multiple-symbol differential. detection of quadrature phase-shift keying (QPSK), a multiple-bit differential detection scheme is described for offset QPSK that also exhibits continuous improvement in performance with increasing observation interval. Being derived from maximum-likelihood considerations together with the representation of differentially encoded offset QPSK as a continuous phase modulation, the proposed scheme is purported to be the most power-efficient scheme for such a modulation and detection method. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Simon, MK (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 24 TC 19 Z9 20 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 JUN PY 2003 VL 51 IS 6 BP 1004 EP 1011 DI 10.1109/TCOMM.2003.813262 PG 8 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 697NC UT WOS:000183948500023 ER PT J AU Svizhenko, A Anantram, MP AF Svizhenko, A Anantram, MP TI Role of scattering in nanotransistors SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article DE contact resistance; FETs; leakage currents; modeling; molecular electronics; MOSFETs; nanotechnology; photons; physics; resistance; scattering; semiconductor device modeling; silicon ID RANGE COULOMB INTERACTIONS; SMALL SI DEVICES; SEMICONDUCTOR-DEVICES; ELECTRON-TRANSPORT; QUANTUM TRANSPORT; TRANSISTORS; MOSFET; REGIME AB We model the influence of scattering along the channel and extension regions of dual gate nanotransistors. It is found that the reduction in drain current due to scattering in the right half of the channel is comparable to the reduction in drain current due to scattering in the left half of the channel, when the channel length is comparable to the scattering length. This is in contrast to a popular belief that scattering in the source end of a nanotransistor is significantly more detrimental to the drive current than scattering elsewhere. As the channel length becomes much larger than the scattering length, scattering in the drain-end is less detrimental to the drive current than scattering near the source-end of the channel. Finally, we show that for nanotransistors, the classical picture of modeling the extension regions as simple series resistances is not valid. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Svizhenko, A (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 27 TC 132 Z9 135 U1 0 U2 7 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD JUN PY 2003 VL 50 IS 6 BP 1459 EP 1466 DI 10.1109/TED.2003.813503 PG 8 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 702XH UT WOS:000184249700005 ER PT J AU Pearlman, JS Crawford, M Jupp, DLB Ungar, S AF Pearlman, JS Crawford, M Jupp, DLB Ungar, S TI Foreword to the Earth Observing 1 - Special issue SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Editorial Material C1 Boeing Co, Seattle, WA 98124 USA. Univ Texas, Ctr Space Res, Austin, TX 78759 USA. CSIRO, Earth Observat Ctr, Canberra, ACT, Australia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pearlman, JS (reprint author), Boeing Co, Seattle, WA 98124 USA. OI Jupp, David/0000-0002-9467-1344 NR 0 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 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUN PY 2003 VL 41 IS 6 BP 1147 EP 1148 DI 10.1109/TGRS.2003.815898 PN 1 PG 2 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 711YM UT WOS:000184768700001 ER PT J AU Ungar, SG Pearlman, JS Mendenhall, JA Reuter, D AF Ungar, SG Pearlman, JS Mendenhall, JA Reuter, D TI Overview of the Earth Observing One (EO-1) mission SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE Advanced Land Imager (ALI); earth observing 1(EO-I); Hyperion; instruments; space systems ID RADIOMETRIC CALIBRATION AB The Earth Observing One (EO-1) satellite, a part of National Aeronautics and Space Administration's New Millennium Program, was developed to demonstrate new technologies and strategies for improved earth observations. It was launched from Vandenburg Air Force Base on November 21,2000. The EO-1 satellite contains three observing instruments supported by a variety of newly developed space technologies. The Advanced Land Imager (ALI) is a prototype for a new generation of Landsat-7 Thematic Mapper. The Hyperion Imaging Spectrometer is the first high spatial resolution imaging spectrometer to orbit the earth. The Linear Etalon Imaging Spectral Array (LEISA) Atmospheric Corrector (LAC) is a high spectral resolution wedge imaging spectrometer designed to measure atmospheric water vapor content. Instrument performances are validated and carefully monitored through a combination of radiometric calibration approaches: solar, lunar, stellar, earth (vicarious), and atmospheric observations complemented by onboard calibration lamps and extensive prelaunch calibration. Techniques for spectral calibration of space-based sensors have been tested and validated with Hyperion. ALI and Hyperion instrument performance continue to meet or exceed predictions well beyond the planned one-year program. This paper reviews the EO-I satellite system and pro-Odes details of the instruments and their performance as measured during the first year of operation. Calibration techniques and tradeoffs between alternative approaches are discussed. An overview of the science applications for instrument performance assessment is presented. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Boeing Co, Phantom Works, Adv Network Centr Operat, Seattle, WA 98124 USA. MIT, Lincoln Lab, Lexington, MA 02420 USA. RP Ungar, SG (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 21 TC 175 Z9 181 U1 4 U2 27 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 2003 VL 41 IS 6 BP 1149 EP 1159 DI 10.1109/TGRS.2003.815999 PN 1 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 711YM UT WOS:000184768700002 ER PT J AU Bindschadler, R Choi, H AF Bindschadler, R Choi, H TI Characterizing and correcting Hyperion detectors using ice-sheet images SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE calibration; hyperspectral; ice sheets; image sensors AB Two Hyperion images of the Greenland ice sheet are used to characterize errors in the visible near-infrared (VNIR) and shortwave infrared (SWIR) detector arrays of Hyperion. Spatial variability in detector output is seen in both arrays and, in both cases, is largest at the shorter wavelengths and decreases as wavelength increases. Standard deviations of the maximum variability are 40 digital numbers (DNs) for the VNIR array and 123 DNs for the SWIR array. Based on a single pair of images, temporal stability is nearly as large and exhibits the same spectral characteristics of large variability at shorter wavelengths and decreasing variability with increasing wavelength. The uniformity and stability of the ice-sheet surface enables a detailed characterization and emphasizes the utility of using ice sheets as targets to achieve on-orbit sensor characterization. C1 NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Lab Hydrosper Proc, Greenbelt, MD 20771 USA. Sci Applicat Int Corp, Beltsville, MD 20705 USA. RP Bindschadler, R (reprint author), NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Lab Hydrosper Proc, Greenbelt, MD 20771 USA. NR 6 TC 13 Z9 16 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUN PY 2003 VL 41 IS 6 BP 1189 EP 1193 DI 10.1109/TGRS.2003.813208 PN 1 PG 5 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 711YM UT WOS:000184768700006 ER PT J AU Green, RO Pavri, BE Chrien, TG AF Green, RO Pavri, BE Chrien, TG TI On-orbit radiometric and spectral calibration characteristics of EO-1 Hyperion derived with an underflight of AVIRIS and in situ measurements at Salar de Arizaro, Argentina SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE Airborne Visible/Infrared Imaging; Spectroradiometer(AVIRIS); calibration; cross-track; Hyperion; imaging spectroscopy; radiometric; spectral ID IMAGING SPECTROMETER AB A calibration experiment was orchestrated on February 7, 2001 at the Salar de Arizaro, Argentina to assess the on-orbit radiometric and spectral calibration of Hyperion. At this high-altitude homogeneous dry salt lakebed, Hyperion, Airborne Visible/Infrared Imaging Spectroradiometer (AVIRIS) and in situ measurements were acquired. At a designated calibration target on Salar de Arizaro, the radiance spectra measured by Hyperion and AVIRIS were compared. In the spectral range from 430-900 nm [visible near-infrared (VNIR)], the ratio of Hyperion over AVIRIS was 0.89, and in the 900 2390-nm [shortwave infrared (SWIR)] spectral range the ratio was 0.79. A comparison of the Hyperion radiance spectrum with a radiative-transfer-code-predicted spectrum for the calibration target showed similar results. These results in conjunction with prelaunch laboratory measurements, on-orbit lunar measurements, other on-orbit calibration experiment results, as well as comparison with Landsat-7, lead to an update of Hyperion radiometric calibration in,December 2001. The compromise update wag to increase the Hyperion radiometric calibration coefficients by 8% in the VNIR and 18% in the SWIR spectrometers. In addition to radiometric accuracy, the on-orbit radiometric precision of Hyperion was assessed at Salar de Arizaro. Noise-equivalent delta radiance was calculated from Hyperion dark signal data and found to be five to ten times higher in comparison to AVIRIS. Also, from a homogeneous portion of Salar de Arizaro the Hyperion SNR was estimated at 140 in the VNIR and 60 in the 2200-nm region of the SWIR spectral range. Cross-track radiometric response was assessed with the AVIRIS dataset that spanned the full Hyperion swath. Within the accuracy of the registration of the datasets, the Hyperion cross-track response was shown to be uniform. Hyperion spectral calibration was assessed with a spectral fitting algorithm using the high spectral resolution radiative transfer modeled spectra for Salar de Arizaro. In the VNIR spectrometer, at the 760-nm oxygen hand, the full cross-track spectral position and full-width at half-maximum (FWHM) of Hyperion were determined. In comparison to the laboratory calibration, spectral shifts ranging from +0.38 to +1.39 nm were derived depending on cross-track spectral position. The on-orbit-derived FWHM ranged from -0.28 to +0.71 nm with respect to the laboratory values. Cross-track spectral calibration was also derived at the 1140-nm water vapor and 2010-nm carbon dioxide absorption features in the SWIR spectrometer.. At 1140 nm, the on-orbit spectral calibration was shifted from +2.2 to +2.5 nm with respect to the laboratory. At 2010 nm, the on-orbit shift was from +3.0 to +3.5 nm compared to the laboratory calibration. These measurements, analyses, and results provide an on-orbit assessment as well as values for update of the Hyperion radiometric and spectral calibration. The calibration experiment at Salar de Arizaro demonstrates a suite of methodologies to assess imaging spectrometer spectral and radiometric characteristics on-orbit. This approach may also be used to monitor these characteristics through time. These Hyperion results further establish the importance of assessment and update of imaging spectrometer measurement characteristics in the operational environment. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Green, RO (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 33 TC 104 Z9 108 U1 1 U2 27 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 2003 VL 41 IS 6 BP 1194 EP 1203 DI 10.1109/TGRS.2003.813204 PN 1 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 711YM UT WOS:000184768700007 ER PT J AU Cairns, B Carlson, BE Ying, RX Lacis, AA Oinas, V AF Cairns, B Carlson, BE Ying, RX Lacis, AA Oinas, V TI Atmospheric correction and its application to an analysis of Hyperion data SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE Atmospheric correction; multiple scattering ID LOOKING IMAGING SPECTROMETERS; SOLAR-REFLECTED SPECTRUM; COLUMNAR WATER-VAPOR; MULTIPLE-SCATTERING; DIFFERENTIAL ABSORPTION; PLANETARY ATMOSPHERES; CORRECTION ALGORITHM; RADIATIVE-TRANSFER; OPTICAL DEPTH; AQUEOUS VAPOR AB In this paper, tradeoffs between speed and accuracy for the atmospheric correction of hyperspectral imagery are examined. Among the issues addressed are the use of scattering calculations on a sparse spectral grid and consequent accuracy and speed tradeoffs, methods for minimizing the required number of quadrature points in multiple-scattering calculations, effects of the vertical profiles of aerosols and absorbing gases on atmospheric correction, and efficient approaches for including the effects of sensor variability (or imperfections) on atmospheric correction. C1 Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. SGT Inc, New York, NY 10025 USA. RP Cairns, B (reprint author), Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA. EM bc25@columbia.edu; bcarlson@giss.nasa.gov; alacis@giss.nasa.gov; voinas@giss.nasa.gov RI Lacis, Andrew/D-4658-2012; Carlson, Barbara/D-8319-2012; OI Cairns, Brian/0000-0002-1980-1022 NR 69 TC 15 Z9 18 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUN PY 2003 VL 41 IS 6 BP 1232 EP 1245 DI 10.1109/TGRS.2003813134 PN 1 PG 14 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 711YM UT WOS:000184768700011 ER PT J AU Bindschadler, R AF Bindschadler, R TI Tracking subpixel-scale sastrugi with Advanced Land Imager SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE ice sheets; image sensors ID ICE-STREAM; VELOCITY; ANTARCTICA AB High radiometric resolution imagery from the Advanced Land Imager (ALI) can detect the spatial reflectance variations associated with sastrugi (snow dunes) on ice sheets. This is shown, in theory, by considering the appropriate SNR ratio of ALI as compared with eight-bit optical sensors and, in practice, with mutlitemporal ALI imagery. Comparison of ALI imagery spanning 7.5 months also shows that the reflectance pattern associated with sastrugi can persist over this interval offering the potential of their use for measuring ice sheet velocity in uncrevassed regions. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Bindschadler, R (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NR 7 TC 7 Z9 7 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 2003 VL 41 IS 6 BP 1373 EP 1377 DI 10.1109/TGRS.2003.812902 PN 1 PG 5 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 711YM UT WOS:000184768700025 ER PT J AU Lu, Z Fielding, E Patrick, MR Trautwein, CM AF Lu, Z Fielding, E Patrick, MR Trautwein, CM TI Estimating lava volume by precision combination of multiple baseline spaceborne and airborne interferometric synthetic aperture radar: The 1997 eruption of Okmok Volcano, Alaska SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE interferometry; remote sensing; surfaces; synthetic aperture radar; terrain mapping ID DIGITAL ELEVATION MODELS; EARTHS SURFACE; MOUNT-ETNA; DEFORMATION; GENERATION; MAGMA; MAPS AB Interferometric synthetic aperture radar (InSAR) techniques are used to calculate the volume of extrusion at Okmok volcano, Alaska by constructing precise digital elevation models (DEMS) that represent volcano topography before and after the 1997 eruption. The posteruption DEM is generated using airborne topographic synthetic aperture radar (TOPSAR) data where a three-dimensional affine transformation is used to account for the misalignments, between different DEM patches. The preeruption DEM is produced using repeat-pass European Remote Sensing satellite data; multiple interferograms are combined to reduce errors due to atmospheric variations, and deformation rates are estimated independently and removed from the interferograms used for DEM generation. The extrusive flow volume associated with the 1997 eruption of Okmok volcano is 0.154 +/- 0.025 km(3). The thickest portion is approximately 50 m, although field measurements of the flow margin's height do not exceed 20 m. The in situ measurements at lava edges are not representative of the total thickness, and precise DEM data are absolutely essential to calculate eruption volume based on lava thickness estimations. This study is an example that demonstrates how InSAR will play a significant role in studying volcanoes in remote areas. C1 US Geol Survey, EROS Data Ctr, Sioux Falls, SD 57198 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Alaska, Inst Geophys, Alaska Volcano Observ, Fairbanks, AK 99775 USA. RP Lu, Z (reprint author), US Geol Survey, EROS Data Ctr, Sioux Falls, SD 57198 USA. RI Fielding, Eric/A-1288-2007; OI Fielding, Eric/0000-0002-6648-8067; Patrick, Matthew/0000-0002-8042-6639 NR 41 TC 57 Z9 62 U1 2 U2 11 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUN PY 2003 VL 41 IS 6 BP 1428 EP 1436 DI 10.1109/TGRS.2003.811553 PN 1 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 711YM UT WOS:000184768700031 ER PT J AU Vaughan, TM Heetderks, WJ Trejo, LJ Rymer, WZ Weinrich, M Moore, MM Kubler, A Dobkin, BH Birbaumer, N Donchin, E Wolpaw, EW Wolpaw, JR AF Vaughan, TM Heetderks, WJ Trejo, LJ Rymer, WZ Weinrich, M Moore, MM Kubler, A Dobkin, BH Birbaumer, N Donchin, E Wolpaw, EW Wolpaw, JR TI Brain-computer interface technology: A review of the second international meeting SO IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING LA English DT Editorial Material DE terms-augmentative communication; brain-computer interface (BCI); electroencephalography (EEG); rehabilitation ID EVENT-RELATED POTENTIALS; MENTAL PROSTHESIS; COMMUNICATION; PATIENT; SIGNAL; CORTEX AB This paper summarizes the Brain-Computer Interfaces for Communication and Control, The Second International Meeting, held in Rensselaerville, NY, in June 2002. Sponsored by the National Institutes of Health and organized by the Wadsworth Center of the New York State Department of Health, the meeting addressed current work and future plans in brain-computer interface (BCI) research. Ninety-two researchers representing 38 different research groups from the United States, Canada, Europe, and China participated. The BCIs discussed at the meeting use electroencephalographic activity recorded from the scalp or single-neuron activity recorded within cortex to control cursor movement, select letters or icons, or operate neuroprostheses. The central element in each BCI is a translation algorithm that converts electrophysiological input from the user into output that controls external devices. BCI operation depends on effective interaction between two adaptive controllers, the user who encodes his or her commands in the electrophysiological input provided to the BCI, and the BCI that recognizes the commands contained in the input and expresses them in device control. Current BCIs have maximum information transfer rates of up to 25 b/min. Achievement of greater speed and accuracy requires improvements in signal acquisition and processing, in translation algorithms, and in user training. These improvements depend on interdisciplinary cooperation among neuroscientists, engineers computer programmers, psychologists, and rehabilitation specialists, and on adoption and widespread application of objective criteria for evaluating alternative methods. The practical use of BCI technology will be determined by the development of appropriate applications and identification of appropriate user groups, and will require careful attention to the needs and desires of individual users. C1 New York State Dept Hlth, Lab Nervous Syst Disorders, Wadsworth Ctr, Albany, NY 12201 USA. Natl Inst Nervous Syst Disorders, NIH, Bethesda, MD 20892 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Rehabil Inst Chicago, Chicago, IL 60611 USA. Northwestern Univ, Chicago, IL 60611 USA. NICHHD, Natl Ctr Med Rehabil Res, NIH, Bethesda, MD 20892 USA. Georgia State Univ, Atlanta, GA 30302 USA. Univ Tubingen, Inst Med Psychol & Behav Neurobiol, D-72074 Tubingen, Germany. Univ Calif Los Angeles, Dept Neurol, Los Angeles, CA 90095 USA. Univ S Florida, Dept Psychol, Tampa, FL 33620 USA. RP Vaughan, TM (reprint author), New York State Dept Hlth, Lab Nervous Syst Disorders, Wadsworth Ctr, Albany, NY 12201 USA. OI Kubler, Andrea/0000-0003-4876-0415 FU NICHD NIH HHS [HD41991-01] NR 54 TC 176 Z9 200 U1 4 U2 37 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1534-4320 J9 IEEE T NEUR SYS REH JI IEEE Trans. Neural Syst. Rehabil. Eng. PD JUN PY 2003 VL 11 IS 2 BP 94 EP 109 DI 10.1109/TNSRE.2003.814799 PG 16 WC Engineering, Biomedical; Rehabilitation SC Engineering; Rehabilitation GA 705EL UT WOS:000184382700001 PM 12899247 ER PT J AU Trejo, LJ Wheeler, KR Jorgensen, CC Rosipal, R Clanton, ST Matthews, B Hibbs, AD Matthews, R Krupka, M AF Trejo, LJ Wheeler, KR Jorgensen, CC Rosipal, R Clanton, ST Matthews, B Hibbs, AD Matthews, R Krupka, M TI Multimodal neuroelectric interface development SO IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING LA English DT Article; Proceedings Paper CT 2nd International Meeting on the Brain-Computer Interfaces for Communication and Control CY JUN, 2002 CL RENSSELAERVILLE, NY DE brain-computer interfaces (BCI); electroencephalogram (EEG); electric field sensors; electromyogram (EMG); neuroelectric interfaces ID BRAIN-COMPUTER INTERFACE; EEG; ENTROPY AB We are developing electromyographic and electroencephalographic methods, which draw control signals for human-computer interfaces from the human nervous system. We have made progress in four areas: 1) real-time pattern recognition algorithms for decoding sequences of forearm muscle activity associated with control gestures; 2) signal-processing strategies for computer interfaces using electroencephalogram (EEG) signals; 3) a flexible, computation, framework for neuroelectric interface research; and d) noncontact sensors, which measure electromyogram or EEG signals without resistive contact to the body. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. OEIC, Worthington, OH 43085 USA. Quantum Appl Sci & Res Inc, San Diego, CA 92121 USA. RP NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM ltrejo@mail.arc.nasa.gov; kwheeler@mail.arc.nasa.gov; cjorgensen@mail.arc.nasa.gov; rrosipal@mail.arc.nasa.gov; sclanton@oeic.net; binatthews@mail.arc.nasa.gov; andy@quasarusa.com; robm@quasarusa.com RI Rosipal, Roman/B-8060-2008 NR 24 TC 26 Z9 27 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1534-4320 EI 1558-0210 J9 IEEE T NEUR SYS REH JI IEEE Trans. Neural Syst. Rehabil. Eng. PD JUN PY 2003 VL 11 IS 2 BP 199 EP 204 DI 10.1109/TNSRE.2003.814426 PG 6 WC Engineering, Biomedical; Rehabilitation SC Engineering; Rehabilitation GA 705EL UT WOS:000184382700028 PM 12899274 ER PT J AU Oldham, TR Sexton, FW Srour, JR AF Oldham, TR Sexton, FW Srour, JR TI Introduction to the commemorative special issue SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Editorial Material C1 NASA, Goddard Space Flight Ctr, QSS Grp Inc, Greenbelt, MD 20771 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Northrop Grunmman Space Technol, Redondo Beach, CA 90278 USA. RP Oldham, TR (reprint author), NASA, Goddard Space Flight Ctr, QSS Grp Inc, Code 661, Greenbelt, MD 20771 USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 2003 VL 50 IS 3 BP 454 EP 456 DI 10.1109/TNS.2003.813138 PN 3 PG 3 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 697GG UT WOS:000183933600001 ER PT J AU Barth, JL Dyer, CS Stassinopoulos, EG AF Barth, JL Dyer, CS Stassinopoulos, EG TI Space, atmospheric, and terrestrial radiation environments SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article ID SINGLE EVENT UPSET; SOLAR PARTICLE EVENTS; GALACTIC COSMIC-RAYS; PROBABILITY MODEL; NEUTRON-FLUX; OCTOBER 1963; SOFT ERRORS; STATIC RAMS; MARCH 24; 1991 SSC AB The progress on developing models of the radiation environment since the 1960s is reviewed with emphasis on models that can be applied to predicting (he performance of microelectronics used in spacecraft and instruments. Space, atmospheric, and ground environments are included. It is shown that models must be adapted continually to account for increased understanding of the dynamics of the radiation environment and the changes in microelectronics technology. The IEEE Nuclear and Space Radiation Effects Conference is a vital forum to report model progress to the radiation effects research community. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. QinetiQ, Farnborough, Hants, England. RP Barth, JL (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 93 TC 114 Z9 118 U1 1 U2 11 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 2003 VL 50 IS 3 BP 466 EP 482 DI 10.1109/TNS.2003.813131 PN 3 PG 17 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 697GG UT WOS:000183933600003 ER PT J AU Oldham, TR McLean, FB AF Oldham, TR McLean, FB TI Total ionizing dose effects in MOS oxides and devices SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Review DE CMOS; ionizing radiation; microelectronics; MOS; radiation effects ID THERMALLY-STIMULATED-CURRENT; INTERFACE-STATE GENERATION; ELECTRON-SPIN-RESONANCE; INDUCED LEAKAGE CURRENT; THIN GATE OXIDES; POSTIRRADIATION ANNEALING RESPONSE; RADIATION-INDUCED CHARGE; TRAPPED POSITIVE CHARGE; SIMOX BURIED OXIDES; SINGLE HARD ERRORS AB This paper reviews the basic physical mechanisms of the interactions of ionizing radiation with MOS oxides, including charge generation, transport, trapping and detrapping, and interface trap formation. Device and circuit effects are also discussed briefly. C1 NASA, Goddard Space Flight Ctr, QSS Grp Inc, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, QSS Grp Inc, Code 661, Greenbelt, MD 20771 USA. EM toldham@pop500.gsfc.nasa.gov; fbarrymc@aol.com NR 155 TC 259 Z9 284 U1 3 U2 39 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9499 EI 1558-1578 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 2003 VL 50 IS 3 BP 483 EP 499 DI 10.1109/TNS.2003.812927 PN 3 PG 17 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 697GG UT WOS:000183933600004 ER PT J AU Reed, RA Kinnison, J Pickel, JC Buchner, S Marshall, PW Kniffin, S LaBel, KA AF Reed, RA Kinnison, J Pickel, JC Buchner, S Marshall, PW Kniffin, S LaBel, KA TI Single-event effects ground testing and on-orbit rate prediction methods: The past, present, and future SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article DE radiation effects in microelectronics; rate predictions; single-event effects (SEEs); space radiation; test facilities ID PICOSECOND PULSED-LASER; UPSET RATE CALCULATIONS; SEU RATE CALCULATION; INDUCED SOFT ERRORS; RAY-INDUCED ERRORS; CHARGE-COLLECTION; CROSS-SECTION; PROTON UPSET; INDUCED TRANSIENTS; OXIDE THICKNESS AB Over the past 27 years, or so, increased concern over single-event effects (SEEs) in spacecraft systems has resulted in research, development, and engineering activities centered around a better understanding of the space radiation environment, SEE predictive methods, ground test protocols, and test facility developments. This research has led to fairly well developed methods for assessing the impact of the space radiation environment on systems that contain SEE sensitive devices and the development of mitigation strategies either at the system or device level. However, as new technology has emerged, these ground test and predictive methods have certain short falls. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. PR&T Inc, Fallbrook, CA 92028 USA. Raytheon ITSS, Greenbelt, MD 20770 USA. RP Reed, RA (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 62 TC 26 Z9 27 U1 0 U2 12 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 2003 VL 50 IS 3 BP 622 EP 634 DI 10.1109/TNS.2003.813331 PN 3 PG 13 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 697GG UT WOS:000183933600012 ER PT J AU Srour, JR Marshall, CJ Marshall, PW AF Srour, JR Marshall, CJ Marshall, PW TI Review of displacement damage effects in silicon devices SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Review DE anneating; damage correlation; defects; displacement damage; nonionizing energy loss; radiation effects; semiconductors silicon; silicon devices ID NEUTRON-IRRADIATED SILICON; P-TYPE SILICON; N-TYPE SILICON; LIGHT-EMITTING-DIODES; TRANSISTOR CURRENT GAIN; 30-MEV ELECTRON DAMAGE; SHORT-TERM ANNEAL; 76 DEGREES K; ENERGY-DEPENDENCE; RADIATION-DAMAGE AB This paper provides a historical review of the literature on the effects of radiation-induced displacement damage in semiconductor materials and devices. Emphasis is placed on effects in technologically important bulk silicon and silicon devices. The primary goals are to provide a guide to displacement damage literature, to offer critical comments regarding that literature in an attempt to identify key findings, to describe how the understanding of displacement damage mechanisms and effects has evolved, and to note current trends. Selected tutorial elements are included as an aid to presenting the review information more clearly and to provide a frame of reference for the terminology used. The primary approach employed is to present information qualitatively while leaving quantitative details to the cited references. A bibliography of key displacement-damage information sources is also provided. C1 Northrop Grumman Space Technol, Redondo Beach, CA 90278 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Northrop Grumman Space Technol, Redondo Beach, CA 90278 USA. NR 175 TC 229 Z9 240 U1 5 U2 48 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9499 EI 1558-1578 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 2003 VL 50 IS 3 BP 653 EP 670 DI 10.1109/TNS.2003.813197 PN 3 PG 18 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 697GG UT WOS:000183933600014 ER PT J AU Pickel, JC Kalma, AH Hopkinson, GR Marshall, CJ AF Pickel, JC Kalma, AH Hopkinson, GR Marshall, CJ TI Radiation effects on photonic imagers - A historical perspective SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Review DE active pixel sensor (APS); charge-coupled device (CCD); displacement damage; IR detectors; photonic imagers; total dose ID CHARGE-COUPLED-DEVICES; FAST-NEUTRON IRRADIATION; ACTIVE PIXEL SENSOR; SILICON DEPLETION REGIONS; RANDOM TELEGRAPH SIGNALS; DARK CURRENT GENERATION; HUBBLE-SPACE-TELESCOPE; HGCDTE MIS CAPACITORS; P-CHANNEL CCDS; INFRARED DETECTORS AB Photonic imagers are being increasingly used in space systems, where they are exposed to the space radiation environment. Unique properties of these devices require special considerations for radiation effects. This paper summarizes the evolution of radiation effects understanding in infrared detector technology, charge coupled devices, and active pixel sensors. The paper provides a discussion of key radiation effects developments and a view of the future of the technologies from a radiation effects perspective. C1 PR&T Inc, Fallbrook, CA 92028 USA. Sci Applicat Int Corp, Albuquerque, NM 87106 USA. SIRA Electopt Ltd UK, Chislehurst, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pickel, JC (reprint author), PR&T Inc, Fallbrook, CA 92028 USA. NR 120 TC 49 Z9 57 U1 1 U2 15 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 2003 VL 50 IS 3 BP 671 EP 688 DI 10.1109/TNS.2003.813126 PN 3 PG 18 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 697GG UT WOS:000183933600015 ER PT J AU Johnston, AH AF Johnston, AH TI Radiation effects in light-emitting and laser diodes SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article DE laser diodes; light-emitting diodes (LEDs); optoelectronic devices; radiation effects ID QUANTUM-WELL LASERS/; PROTON DAMAGE; ENERGY-DEPENDENCE; DISPLACEMENT DAMAGE; GAMMA-IRRADIATION; SEMICONDUCTOR-LASERS; GALLIUM-ARSENIDE; GAAS LEDS; DEVICES; OPTOCOUPLERS AB This paper discusses radiation effects in light-emitting diodes (LEDs) and laser diodes in the visible and near infrared region. Although initial evaluations of radiation damage in these types of optical emitters were done more than 30 years ago, modern LEDs and laser diodes respond somewhat differently to radiation because of the many advances in fabrication and materials technology that have occurred during the last 30 years. Results from newer technologies are discussed, along with revised interpretations of older results in the literature. The dependence of damage on particle type and energy, which has been revised by more recent experimental work, is also discussed in the paper. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Johnston, AH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 73 TC 18 Z9 21 U1 0 U2 5 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 2003 VL 50 IS 3 BP 689 EP 703 DI 10.1109/TNS.2003.812926 PN 3 PG 15 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 697GG UT WOS:000183933600016 ER PT J AU Saripalli, S Montgomery, JF Sukhatme, GS AF Saripalli, S Montgomery, JF Sukhatme, GS TI Visually guided landing of an unmanned aerial vehicle SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Article; Proceedings Paper CT 19th IEEE International Conference on Robotics and Automation (ICRA) CY MAY 11-15, 2002 CL WASHINGTON, DC SP IEEE Robot & Automat Soc DE autonomous helicopter; autonomous landing; unmanned aerial vehicle; vision-based navigation AB We present the design and implementation of a real-time, vision-based landing algorithm for an autonomous helicopter. The landing algorithm is integrated with algorithms for visual acquisition of the target (a helipad) and navigation to the target, from an arbitrary initial position and orientation. We use vision for precise target detection and recognition, and a combination of vision and Global Positioning System for navigation. The helicopter updates its landing target parameters based on vision and uses an onboard behavior-based controller to follow a path to the landing site. We present significant results from flight trials in the field which demonstrate that our detection, recognition, and control algorithms are accurate, robust, and repeatable. C1 Univ So Calif, Ctr Robot & Embedded Syst, Robot Embedded Syst Lab, Los Angeles, CA 90089 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Univ So Calif, Ctr Robot & Embedded Syst, Robot Embedded Syst Lab, Los Angeles, CA 90089 USA. EM srik@robotics.usc.edu; monty@helios.jpl.nasa.gov; gaurav@robotics.usc.edu RI Saripalli, Srikanth/I-6295-2012 NR 25 TC 191 Z9 210 U1 10 U2 58 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1042-296X J9 IEEE T ROBOTIC AUTOM JI IEEE Trans. Robot. Autom. PD JUN PY 2003 VL 19 IS 3 BP 371 EP 380 DI 10.1109/TRA.2003.810239 PG 10 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA 691HP UT WOS:000183600300002 ER PT J AU Schnase, JL Cushing, J Frame, M Frondorf, A Landis, E Maier, D Silberschatz, A AF Schnase, JL Cushing, J Frame, M Frondorf, A Landis, E Maier, D Silberschatz, A TI Information technology challenges of biodiversity and ecosystems informatics SO INFORMATION SYSTEMS LA English DT Article DE biodiversity; ecosystems; informatics; ecological forecasting AB Computer scientists, biologists, and natural resource managers recently met to examine the prospects for advancing computer science and information technology research by focusing on the complex and often-unique challenges found in the biodiversity and ecosystem domain. The workshop and its final report reveal that the biodiversity and ecosystem sciences are fundamentally information sciences and often address problems having distinctive attributes of scale and socio-technical complexity. The paper provides an overview of the emerging field of biodiversity and ecosystem informatics and demonstrates how the demands of biodiversity and ecosystem research can advance our understanding and use of information technologies. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Earth & Space Data Comp Div, Greenbelt, MD 20771 USA. Evergreen State Coll, Olympia, WA 98505 USA. US Geol Survey, Reston, VA USA. Natl Resources Informat Management, Stillwater, MN 55082 USA. Oregon Grad Inst, Beaverton, OR 97006 USA. Bell Labs, Murray Hill, NJ 07974 USA. RP Schnase, JL (reprint author), NASA, Goddard Space Flight Ctr, Earth & Space Data Comp Div, Greenbelt, MD 20771 USA. OI Frame, Mike/0000-0001-9995-2172 NR 5 TC 12 Z9 12 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0306-4379 J9 INFORM SYST JI Inf. Syst. PD JUN PY 2003 VL 28 IS 4 BP 339 EP 345 AR PII S0306-4379(02)00070-4 DI 10.1016/S0306-4379(02)00070-4 PG 7 WC Computer Science, Information Systems SC Computer Science GA 676DT UT WOS:000182737100006 ER PT J AU Hochedez, JF Appourchaux, T Belsky, A Castex, MC Deneuville, A Dhez, P Fleck, B Hainaut, O Idir, M Kleider, JP Lemaire, P Monroy, E Munoz, E Muret, P Nesladek, M Omnes, F Pau, J Peacock, A Schuhle, U Van Hoof, C AF Hochedez, JF Appourchaux, T Belsky, A Castex, MC Deneuville, A Dhez, P Fleck, B Hainaut, O Idir, M Kleider, JP Lemaire, P Monroy, E Munoz, E Muret, P Nesladek, M Omnes, F Pau, J Peacock, A Schuhle, U Van Hoof, C TI Diamond imager and nitrides for UV observation of the sun SO JOURNAL DE PHYSIQUE IV LA French DT Article; Proceedings Paper CT 6th Meeting on Coherent Sources and Incoherent Sources of UV VUV and X CY JUN 11-14, 2002 CL OLERON, FRANCE ID SOLAR ORBITER; DETECTORS; PHYSICS C1 Observ Royal Belgique, Solar Phys Dept, B-1180 Brussels, Belgium. European Space Agcy, Estec, Solar Syst Div, Noordwijk, Netherlands. CELIA, Bordeaux, France. CNRS, LPL, Villetaneuse, France. CNRS, LEPES, Grenoble, France. LIXAM, Orsay, France. Goddard Space Flight Ctr, ESA, Solar Syst Div, Greenbelt, MD 20771 USA. IAS, Orsay, France. LURE SOLEIL, Orsay, France. LGEP, Gif Sur Yvette, France. CEA, Grenoble, France. DIE UPM, Madrid, Spain. IMO, Diepenbeek, Belgium. CHREA, Valbonne, France. MPAE, Katlenburg Lindau, Germany. IMEC, Louvain, Belgium. RP Hochedez, JF (reprint author), Observ Royal Belgique, Solar Phys Dept, Circular Ave 3, B-1180 Brussels, Belgium. RI Fleck, Bernhard/C-9520-2012; Monroy, Eva/D-9593-2011 OI Monroy, Eva/0000-0001-5481-3267 NR 8 TC 1 Z9 1 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD JUN PY 2003 VL 108 BP 227 EP 231 DI 10.1051/jp4:20030632 PG 5 WC Physics, Multidisciplinary SC Physics GA 706XT UT WOS:000184480900050 ER PT J AU Turner, DD Ackerman, SA Baum, BA Revercomb, HE Yang, P AF Turner, DD Ackerman, SA Baum, BA Revercomb, HE Yang, P TI Cloud phase determination using ground-based AERI observations at SHEBA SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID WATER-VAPOR; MU-M; RADIATIVE PROPERTIES; THERMODYNAMIC-PHASE; ATMOSPHERIC FLUXES; OPTICAL-CONSTANTS; LIGHT-SCATTERING; CLIMATE RESEARCH; COOLING RATES; ARCTIC-OCEAN AB A new technique for ascertaining the thermodynamic cloud phase from high-spectral-resolution ground-based infrared measurements made by the Atmospheric Emitted Radiance Interferometer (AERI) is presented. This technique takes advantage of the differences in the index of refraction of ice and water between 11 and 19 mum. The differences in the refractive indices translate into differences in cloud emissivity at the various wavelengths, which are used to determine whether clouds contain only ice particles or only water particles, or are mixed phase. Simulations demonstrate that the algorithm is able to ascertain correctly the cloud phase under most conditions, with the exceptions occurring when the optical depth of the cloud is dominated by liquid water (> 70%). Several examples from the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment are presented, to demonstrate the capability of the algorithm, in which a collocated polarization-sensitive lidar is used to provide insight to the true thermodynamic phase of the clouds. Statistical comparisons with this lidar during the SHEBA campaign demonstrate that the algorithm identifies the cloud as either an ice or mixed-phase cloud approximately 80% of time when a single-layer cloud with an average depolarization above 10% exists that is not opaque to the AERI. For single-layer clouds having depolarization of less than 10%, the algorithm identifies the cloud as a liquid water cloud over 50% of the time. This algorithm was applied to 7 months of data collected during SHEBA, and monthly statistics on the frequency of ice, water, and mixed-phase clouds are presented. C1 Univ Wisconsin, CIMSS, Madison, WI 53706 USA. Pacific NW Natl Lab, Richland, WA USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX USA. RP Turner, DD (reprint author), Univ Wisconsin, CIMSS, 1225 W Dayton St, Madison, WI 53706 USA. EM dturner@ssec.wisc.edu RI Yang, Ping/B-4590-2011; Baum, Bryan/B-7670-2011; Ackerman, Steven/G-1640-2011 OI Baum, Bryan/0000-0002-7193-2767; Ackerman, Steven/0000-0002-4476-0269 NR 40 TC 51 Z9 53 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 JUN PY 2003 VL 42 IS 6 BP 701 EP 715 DI 10.1175/1520-0450(2003)042<0701:CPDUGA>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 683LU UT WOS:000183151500004 ER PT J AU Durden, SL Im, E Haddad, ZS Li, L AF Durden, SL Im, E Haddad, ZS Li, L TI Comparison of TRMM precipitation radar and airborne radar data SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID SPACEBORNE RADAR; RAIN; ATTENUATION; ALGORITHMS; RETRIEVAL AB The first spaceborne weather radar is the precipitation radar (PR) on the Tropical Rainfall Measuring Mission (TRMM), which was launched in 1997. As part of the TRMM calibration and validation effort, an airborne rain-mapping radar (ARMAR) was used to make underflights of TRMM during the B portion of the Texas and Florida Underflights (TEFLUN-B) and the third Convection and Moisture Experiment (CAMEX-3) in 1998 and the Kwajalein Experiment (KWAJEX) in 1999. The TRMM PR and ARMAR both operate at 14 GHz, and both instruments use a downward-looking, cross-track scanning geometry, which allows direct comparison of data. Nearly simultaneous PR and ARMAR data were acquired in seven separate cases. These data are compared to examine the effects of larger resolution volume and lower sensitivity in the PR data relative to ARMAR. The PR and ARMAR data show similar structures, although the PR data tend to have lower maximum reflectivities and path attenuations because of nonuniform beam-filling effects. Nonuniform beam filling can also cause a bias in the observed path attenuation relative to that corresponding to the beam-averaged rain rate. The PR rain-type classification is usually consistent with the ARMAR data. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Durden, SL (reprint author), CALTECH, Jet Prop Lab, JPL 300-243,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 12 Z9 13 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 JUN PY 2003 VL 42 IS 6 BP 769 EP 774 DI 10.1175/1520-0450(2003)042<0769:COTPRA>2.0.CO;2 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 683LU UT WOS:000183151500008 ER PT J AU Strapp, JW Oldenburg, J Ide, R Lilie, L Bacic, S Vukovic, Z Oleskiw, M Miller, D Emery, E Leone, G AF Strapp, JW Oldenburg, J Ide, R Lilie, L Bacic, S Vukovic, Z Oleskiw, M Miller, D Emery, E Leone, G TI Wind tunnel measurements of the response of hot-wire liquid water content instruments to large droplets SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID OPTICAL ARRAY PROBE AB Wet wind tunnel tests were performed on more than 23 cloud liquid water content (LWC) probes and drop spectrometers at the NASA Icing Research Tunnel, with a main objective to characterize their response to large-droplet conditions. As a part of this study, the LWC and median volume diameter (MVD) reference values of the tunnel were examined, and accuracies were estimated and reported herein. Alternative MVDs were calculated from measurements conducted during the study. MVD accuracy was particularly difficult to estimate due to the lack of accepted standards, and MVD estimates were quite sensitive to the complement of instruments used to generate composite droplet spectra. Four hot-wire LWC probes were tested to characterize the LWC response as a function of cloud MVD. A response reduction was observed with increasing MVD for all three probes with cylindrical hot wires, most significant for the probe with the smallest wire diameter. The response of the Nevzorov total water content (TWC) probe, with its relatively large-diameter conical hot wire, did not roll off appreciably within the range of MVDs tested, although significantly larger inertial collision efficiency corrections were predicted for smaller droplets. The results corroborate previous studies that suggest re-entrainment of collected water likely creates a rolloff of the response of small-diameter cylindrical hot-wire probes, but also suggest that the aerodynamic design of the Nevzorov TWC probe inhibits re-entrainment by trapping droplets that enter its sample volume. C1 Meteorol Serv Canada, Cloud Phys Res Div, Downsview, ON M3H ST4, Canada. NASA, Glenn Res Ctr, Cleveland, OH USA. Natl Res Council Canada, Ottawa, ON, Canada. Ctr Italiano Ric Aerosp, Capua, Italy. RP Strapp, JW (reprint author), Meteorol Serv Canada, Cloud Phys Res Div, 4905 Dufferin St, Downsview, ON M3H ST4, Canada. NR 31 TC 23 Z9 26 U1 2 U2 9 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 2003 VL 20 IS 6 BP 791 EP 806 DI 10.1175/1520-0426(2003)020<0791:WTMOTR>2.0.CO;2 PG 16 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 682DU UT WOS:000183076700002 ER PT J AU Berbery, EH Fox-Rabinovitz, MS AF Berbery, EH Fox-Rabinovitz, MS TI Multiscale diagnosis of the North American monsoon system using a variable-resolution GCM SO JOURNAL OF CLIMATE LA English DT Article ID SOUTHWESTERN UNITED-STATES; GULF-OF-CALIFORNIA; SINGULAR-SPECTRUM ANALYSIS; SHALLOW-WATER EQUATIONS; MARITIME TROPICAL AIR; STRETCHED-GRID GCM; LOW-LEVEL JET; REGIONAL CLIMATE; GENERAL-CIRCULATION; MEXICAN MONSOON AB The onset and evolution of the North American monsoon system during the summer of 1993 were examined from regional to large scales using the National Aeronautics and Space Administration (NASA) Goddard Earth Observing System (GEOS) stretched-grid GCM. The model's grid spacing for the dynamical core ranges from 0.4degrees x 0.5degrees in latitude - longitude over the United States to about 2.5degrees x 3.5degrees at the antipode, and the physical package is solved on an intermediate 1degrees x 1degrees uniform grid. A diagnostic analysis of the monsoon's onset reveals the development of a positive potential temperature (theta) anomaly at the surface that favors a lower-level cyclonic circulation, while a negative potential vorticity (PV) anomaly below the tropopause induces an upper-level anticyclonic circulation. Ignoring diabatic effects, this pattern is consistent with the superimposition of idealized PV and theta anomalies as previously discussed in the literature. The inclusion of the smaller-scale features of the core monsoon in the model simulation helps represent the continental out-of-phase relationship between the monsoon and the southern Great Plains precipitation, giving additional support to earlier results that highlight the strong nature of the link. A pattern of increased precipitation over the core monsoon is consistently associated with increases of moisture flux convergence and ascending motions, and the development of upper-level wind divergence. On the other hand, the southern Great Plains have a simultaneous decrease of precipitation associated with a change from convergence to divergence of moisture flux, decreased ascending motions, and a development of upper-level wind convergence. The Gulf of California low-level jet (LLJ) was inspected with a multitaper method spectral analysis, showing significant peaks for both the diurnal cycle and synoptic-scale modes, the latter resulting from the recurrent passage of Gulf surges. Those modes were then separated with a singular spectrum analysis decomposition. Compared with the Great Plains LLJ, the Gulf of California LLJ has a weaker diurnal cycle amplitude and a smaller ratio of diurnal cycle to synoptic-scale amplitudes. Additionally, the 1993 southwestern U. S. monsoon was analyzed by constructing composites of surge and no-surge cases. Given the particular characteristics of 1993 that include the effect of Hurricane Hilary, the extension of these results to other years needs to be assessed. Surges are associated with a strong Gulf of California LLJ and increased moisture flux from the Gulf into Arizona, and they accounted for 80% - 100% of the simulated precipitation over Arizona, western New Mexico, and southern Utah. As distance from the Gulf is increased, there is a rapid decay of this percentage so that northern Utah and eastern New Mexico precipitation is almost unrelated to the surges. The results from this research show that the model's regional downscaling results in a realistic representation of the monsoon-related circulations at multiple scales. C1 Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. Univ Maryland, Earth Syst Sci Interact Ctr, College Pk, MD 20742 USA. NASA, Data Assimilat Off, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Berbery, EH (reprint author), Univ Maryland, Dept Meteorol, 3427 Comp & Space Sci Bldg, College Pk, MD 20742 USA. RI Berbery, Ernesto/F-4560-2010 OI Berbery, Ernesto/0000-0003-2587-3345 NR 69 TC 33 Z9 33 U1 1 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 JUN PY 2003 VL 16 IS 12 BP 1929 EP 1947 DI 10.1175/1520-0442(2003)016<1929:MDOTNA>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 688WK UT WOS:000183460100004 ER PT J AU Fairbridge, RW AF Fairbridge, RW TI Mesopotamia: Cradle of civilization SO JOURNAL OF COASTAL RESEARCH LA English DT Editorial Material C1 Columbia Univ, New York, NY 10027 USA. NASA, GISS, New York, NY USA. RP Fairbridge, RW (reprint author), Columbia Univ, New York, NY 10027 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU COASTAL EDUCATION & RESEARCH FOUNDATION PI LAWRENCE PA 810 EAST 10TH STREET, LAWRENCE, KS 66044 USA SN 0749-0208 J9 J COASTAL RES JI J. Coast. Res. PD SUM PY 2003 VL 19 IS 3 BP III EP IV PG 2 WC Environmental Sciences; Geography, Physical; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Physical Geography; Geology GA 712TU UT WOS:000184814000001 ER PT J AU Resnick, A AF Resnick, A TI Use of optical tweezers for colloid science SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE hard-sphere colloids; optical trapping; refractive index; microrheology ID FORCES; SCATTERING; SPHERE; DESIGN; BEAM; TRAP AB A space-borne optical tweezer apparatus for use with colloidal crystallization experiments has been characterized. The trapping force has been measured as a function of index mismatch between colloidal microspheres and the surrounding fluid and as a function of particle size. This work also presents a method to determine the refractive index of a colloidal microsphere, which is then used to calculate the applied trapping force for the case of an arbitrary background fluid. This is useful for work with dense colloidal suspensions when the usual (e.g., Stokes flow) trap force measurement methods do not apply, as well as microrheological studies of complex soft matter. (C) 2003 Elsevier Science (USA). All rights reserved. C1 NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. RP Resnick, A (reprint author), NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Mailstop 110-3,2100 Brookpk Rd, Cleveland, OH 44135 USA. NR 25 TC 17 Z9 17 U1 2 U2 6 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD JUN 1 PY 2003 VL 262 IS 1 BP 55 EP 59 DI 10.1016/S0021-9797(03)00193-0 PG 5 WC Chemistry, Physical SC Chemistry GA 682AY UT WOS:000183069100007 PM 16256580 ER PT J AU Simon, MK Wang, JB AF Simon, MK Wang, JB TI Noncoherent detection of orthogonal modulation combined with Alamouti space-time coding SO JOURNAL OF COMMUNICATIONS AND NETWORKS LA English DT Article DE digital communications; fading channels; noncoherent detection; space-time coding ID DIFFERENTIAL UNITARY SPACE; TRANSMIT DIVERSITY; CODES; COMMUNICATION; CONSTELLATIONS; CAPACITY; DESIGNS AB In this paper, we investigate the error probability performance of noncoherently detected orthogonal modulation combined with Alamouti space-time block coding. We find that there are two types of pair-wise error probabilities that characterize the performance. We employ methods that allow a direct evaluation of exact, closed-form expressions for these error probabilities. Theoretical as well as numerical results show that noncoherent orthogonal modulation combined with space-time block coding (STBC) achieves full spatial diversity. We derive an expression for approximate average bit error probability for M-ary orthogonal signaling that allows one to show the tradeoff between increased rate and performance degradation. C1 CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90024 USA. RP Simon, MK (reprint author), Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90024 USA. NR 26 TC 0 Z9 0 U1 0 U2 0 PU KOREAN INST COMMUNICATIONS SCIENCES (K I C S) PI SEOUL PA HYUNDAI KIRIM OFFICETEL 1504-6 SEOCHODONG 1330-18, SEOCHOKU, SEOUL 137-070, SOUTH KOREA SN 1229-2370 J9 J COMMUN NETW-S KOR JI J. Commun. Netw. PD JUN PY 2003 VL 5 IS 2 BP 124 EP 134 PG 11 WC Computer Science, Information Systems; Telecommunications SC Computer Science; Telecommunications GA 701XB UT WOS:000184193300005 ER PT J AU Lien, MC Schweickert, R Proctor, RW AF Lien, MC Schweickert, R Proctor, RW TI Task switching and response correspondence in the psychological refractory period paradigm SO JOURNAL OF EXPERIMENTAL PSYCHOLOGY-HUMAN PERCEPTION AND PERFORMANCE LA English DT Article ID SET RECONFIGURATION; OVERLAPPING TASKS; PERFORMANCE; STIMULUS; BOTTLENECK; REPETITION; ATTENTION; COSTS; MODEL AB Three experiments examined the effects of task switching and response correspondence in a psychological refractory period paradigm. A letter task (vowel-consonant) and a digit task (odd-even) were combined to form 4 possible dual-task pairs in each trial: letter-letter, letter-digit, digit-digit, and digit-letter. Foreknowledge of task transition (repeat or switch) and task identity (letter or digit) was varied across experiments: no foreknowledge in Experiment 1, partial foreknowledge (task transition only) in Experiment 2, and full foreknowledge in Experiment 3. For all experiments, the switch cost for Task 2 was additive with stimulus onset asynchrony, and the response-correspondence effect for Task 2 was numerically smaller in the switch condition than in the repeat condition. These outcomes suggest that reconfiguration for Task 2 takes place after the central processing of Task I and that the crosstalk correspondence effect is due to response activation by way of stimulus-response associations. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Purdue Univ, Dept Psychol Sci, W Lafayette, IN 47907 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 51 TC 48 Z9 48 U1 0 U2 5 PU AMER PSYCHOLOGICAL ASSOC PI WASHINGTON PA 750 FIRST ST NE, WASHINGTON, DC 20002-4242 USA SN 0096-1523 EI 1939-1277 J9 J EXP PSYCHOL HUMAN JI J. Exp. Psychol.-Hum. Percept. Perform. PD JUN PY 2003 VL 29 IS 3 BP 692 EP 712 DI 10.1037/0096-1523.29.3.692 PG 21 WC Psychology; Psychology, Experimental SC Psychology GA 691ET UT WOS:000183592500012 PM 12848334 ER PT J AU Van Heel, N Pettit, J Rice, BL Smith, SM AF Van Heel, N Pettit, J Rice, BL Smith, SM TI Meeting expanding needs for nutrient specificity: the NASA case study SO JOURNAL OF FOOD COMPOSITION AND ANALYSIS LA English DT Article DE nutrient database; chemically analyzed nutrients; dietary supplements; fortification ID DATABASE AB Food and nutrient databases are populated with data obtained from a variety of sources including USDA Reference Tables, scientific journals, food manufacturers and foreign food tables. The food and nutrient database maintained by the Nutrition Coordinating Center (NCC) at the University of Minnesota is continually updated with current nutrient data that are carefully evaluated for reliability and relevance before incorporation into the database; however, some values are obtained from calculations or from similar foods rather than from direct chemical analysis of specific foods. Precise nutrient values for specific foods are essential to the nutrition program at the National Aeronautics and Space Administration (NASA). Specific foods to be included in the menus of astronauts are chemically analyzed at the Johnson Space Center for selected nutrients. A request from NASA for a method to permit NASA nutritionists to enter chemically analyzed nutrient values for space flight food items into the Nutrition Data System for Research (NDS-R) software resulted in modifications of the database and interview system. The database was expanded by entering the nutrients of interest to NASA as though they were individual foods, thereby allowing entry of a "recipe" of nutrients that exactly match the Johnson Space Center chemical analysis of each specific flight food. Subsequent work by NCC resulted in further modifications to extend the method for related uses by other research studies. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Univ Minnesota, Nutr Coordinating Ctr, Minneapolis, MN 55454 USA. NASA, Johnson Space Ctr, Houston, TX 77058 USA. RP Van Heel, N (reprint author), Univ Minnesota, Nutr Coordinating Ctr, 1300 S 2nd St Suite 300, Minneapolis, MN 55454 USA. NR 6 TC 1 Z9 1 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 0889-1575 J9 J FOOD COMPOS ANAL JI J. Food Compos. Anal. PD JUN PY 2003 VL 16 IS 3 BP 299 EP 303 DI 10.1016/S0889-1575(03)00047-4 PG 5 WC Chemistry, Applied; Food Science & Technology SC Chemistry; Food Science & Technology GA 692NQ UT WOS:000183667500007 ER PT J AU Dansby, MY Bovell-Benjamin, AC AF Dansby, MY Bovell-Benjamin, AC TI Production and proximate composition of a hydroponic sweet potato flour during extended storage SO JOURNAL OF FOOD PROCESSING AND PRESERVATION LA English DT Article AB In developing countries, where limited transport infrastructure exists, processing the sweet potato (Ipomoea batatas (L.) Lam) into flour provides an alternative to the difficulties associated with storage and transport of the raw roots. The objectives of this study were: (1) to process hydroponic sweet potato roots into flour; and (2) to evaluate the nutritive composition and the color of the processed hydroponic sweet potato flour during storage. The TU-82-155 hydroponic sweet potatoes were processed into flour and stored for five months at room and refrigerated temperatures. The sweet potato flour contained 3.0%, 4.5%, 1.0%, 1.0%, 90.6% moisture, ash, fat, protein, and carbohydrate, respectively, with no significant changes during storage. The *L values for the sweet potato flour increased as storage time increased, but the *a and *b values decreased. Hydroponic sweet potato roots could be processed into flour and stored at 4C or 21C to 25C for five months without deterioration in quality. C1 Tuskegee Univ, Dept Food & Nutrit Sci, Ctr Food & Environm Syst Human Explorat Space, NASA, Tuskegee, AL 36088 USA. RP Bovell-Benjamin, AC (reprint author), Tuskegee Univ, Dept Food & Nutrit Sci, Ctr Food & Environm Syst Human Explorat Space, NASA, 300-A Campbell Hall, Tuskegee, AL 36088 USA. NR 25 TC 9 Z9 9 U1 3 U2 6 PU FOOD NUTRITION PRESS INC PI TRUMBULL PA 6527 MAIN ST, P O BOX 374, TRUMBULL, CT 06611 USA SN 0145-8892 J9 J FOOD PROCESS PRES JI J. Food Process Preserv. PD JUN PY 2003 VL 27 IS 2 BP 153 EP 164 DI 10.1111/j.1745-4549.2003.tb00508.x PG 12 WC Food Science & Technology SC Food Science & Technology GA 689VN UT WOS:000183513800006 ER PT J AU Bergen, KM Conard, SG Houghton, RA Kasischke, ES Kharuk, VI Krankina, ON Ranson, KJ Shugart, HH Sukhinin, AI Treyfeld, RF AF Bergen, KM Conard, SG Houghton, RA Kasischke, ES Kharuk, VI Krankina, ON Ranson, KJ Shugart, HH Sukhinin, AI Treyfeld, RF TI NASA and Russian scientists observe land-cover and land-use change and carbon in Russian forests SO JOURNAL OF FORESTRY LA English DT Article DE international forestry; remote sensing; Russia ID WESTERN SAYANI MOUNTAINS; SATELLITE DETECTION; SAR DATA; EMISSIONS; SIBERIA; SMOKE AB In 1997, several project teams of the NASA Land-Cover Land-Use Change Program began working with Russian organizations to try to quantify and understand the past, present, and future land-cover and land-use trends in Russian boreal forests. Selected results of completed and ongoing research projects are discussed in four categories: forest dynamics, fire and fire behavior, carbon budgets, and new remote sensing analysis methods. This research has helped pave the way for collaborations with international organizations and other networks, and collaborations at several scales are now making it possible for Russian and US scientists to work together to further our knowledge on the influence of land-cover and land-use change throughout the world. C1 Univ Michigan, Sch Nat Resources & Environm, Ann Arbor, MI 48109 USA. Univ Michigan, Ctr Russian & E European Studies, Ann Arbor, MI 48109 USA. US Forest Serv, USDA, Washington, DC 20250 USA. Woods Hole Res Ctr, Woods Hole, MA 02543 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. Sukachev Inst Forest, Krasnoyarsk, Russia. Oregon State Univ, Dept Forest Sci, Corvallis, OR 97331 USA. Goddard Space Flight Ctr, Greenbelt, MD USA. Univ Virginia, Charlottesville, VA 22903 USA. Sukachev Forest Res Inst, Remote Sensing Facil, Krasnoyarsk, Russia. NW State Forest Inventory Enterprise, St Petersburg, Russia. RP Bergen, KM (reprint author), Univ Michigan, Sch Nat Resources & Environm, 430 E Univ, Ann Arbor, MI 48109 USA. RI Ranson, Kenneth/G-2446-2012; Conard, Susan/H-8158-2013; Shugart, Herman/C-5156-2009 OI Ranson, Kenneth/0000-0003-3806-7270; NR 28 TC 5 Z9 5 U1 0 U2 4 PU SOC AMER FORESTERS PI BETHESDA PA 5400 GROSVENOR LANE, BETHESDA, MD 20814 USA SN 0022-1201 J9 J FOREST JI J. For. PD JUN PY 2003 VL 101 IS 4 BP 34 EP 41 PG 8 WC Forestry SC Forestry GA 683DP UT WOS:000183132700008 ER PT J AU Anderson, CJ Arritt, RW Takle, ES Pan, ZT Gutowski, WJ Otieno, FO da Silva, R Caya, D Christensen, JH Luthi, D Gaertner, MA Gallardo, C Giorgi, F Hong, SY Jones, C Juang, HMH Katzfey, JJ Lapenta, WM Laprise, R Larson, JW Liston, GE McGregor, JL Pielke, RA Roads, JO Taylor, JA AF Anderson, CJ Arritt, RW Takle, ES Pan, ZT Gutowski, WJ Otieno, FO da Silva, R Caya, D Christensen, JH Luthi, D Gaertner, MA Gallardo, C Giorgi, F Hong, SY Jones, C Juang, HMH Katzfey, JJ Lapenta, WM Laprise, R Larson, JW Liston, GE McGregor, JL Pielke, RA Roads, JO Taylor, JA TI Hydrological processes in regional climate model simulations of the central United States flood of June-July 1993 SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID LOW-LEVEL JET; WATER-VAPOR TRANSPORT; MESOSCALE CONVECTIVE COMPLEXES; BOUNDARY-LAYER; NORTH-AMERICA; GREAT-PLAINS; SPECTRAL MODEL; SURFACE EVAPORATION; SCALE ENVIRONMENT; LAND-SURFACE AB Thirteen regional climate model(RCM) simulations of June - July 1993 were compared with each other and observations. Water vapor conservation and precipitation characteristics in each RCM were examined for a 108 x 10degrees subregion of the upper Mississippi River basin, containing the region of maximum 60-day accumulated precipitation in all RCMs and station reports. All RCMs produced positive precipitation minus evapotranspiration ( P - E > 0), though most RCMs produced P - E below the observed range. RCM recycling ratios were within the range estimated from observations. No evidence of common errors of E was found. In contrast, common dry bias of P was found in the simulations. Daily cycles of terms in the water vapor conservation equation were qualitatively similar in most RCMs. Nocturnal maximums of P and C ( convergence) occurred in 9 of 13 RCMs, consistent with observations. Three of the four driest simulations failed to couple P and C overnight, producing afternoon maximum P. Further, dry simulations tended to produce a larger fraction of their 60-day accumulated precipitation from low 3-h totals. In station reports, accumulation from high ( low) 3-h totals had a nocturnal ( early morning) maximum. This time lag occurred, in part, because many mesoscale convective systems had reached peak intensity overnight and had declined in intensity by early morning. None of the RCMs contained such a time lag. It is recommended that short-period experiments be performed to examine the ability of RCMs to simulate mesoscale convective systems prior to generating long-period simulations for hydroclimatology. C1 Iowa State Univ, Dept Agron, Ames, IA 50011 USA. Iowa State Univ, Dept Geol & Atmospher Sci, Ames, IA 50011 USA. CSIRO, Aspendale, Vic, Australia. Danish Meteorol Inst, Copenhagen, Denmark. Natl Ctr Environm Predict, Camp Springs, MD USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Quebec, Dept Earth & Atmospher Sci, Montreal, PQ H3C 3P8, Canada. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Int Ctr Theoret Phys, Trieste, Italy. Swedish Meteorol & Hydrol Inst, Rossby Ctr, S-60176 Norrkoping, Sweden. ETH, Swiss Fed Inst Technol, Zurich, Switzerland. Univ Castilla La Mancha, Environm Sci Fac, Toledo, Spain. Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Duke Univ, Dept Civil & Environm Engn, Durham, NC 27706 USA. Yonsei Univ, Dept Atmospher Sci, Seoul 120749, South Korea. RP Anderson, CJ (reprint author), Iowa State Univ, Dept Agron, 3010 Agron Hall, Ames, IA 50011 USA. EM candersn@iastate.edu RI Pielke, Roger/A-5015-2009; Taylor, John/E-5894-2010; McGregor, John/C-6646-2012; Pan, Zaitao/D-7846-2012; Hong, Song-You/I-3824-2012; Katzfey, Jack/K-1231-2012; Giorgi, Filippo/C-3169-2013; Christensen, Jens/C-4162-2013; Ramos-da-Silva, Renato/I-4759-2012 OI Taylor, John/0000-0001-9003-4076; Katzfey, Jack/0000-0002-0604-8860; Christensen, Jens/0000-0002-9908-8203; NR 75 TC 39 Z9 40 U1 3 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PD JUN PY 2003 VL 4 IS 3 BP 584 EP 598 DI 10.1175/1525-7541(2003)004<0584:HPIRCM>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 684VM UT WOS:000183227300008 ER PT J AU Dholakia, GR Fan, W Koehne, J Han, J Meyyappan, M AF Dholakia, GR Fan, W Koehne, J Han, J Meyyappan, M TI Topography and transport properties of oligo(phenylene ethynylene) molecular wires studied by scanning tunneling microscopy SO JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY LA English DT Article DE oligo(phenylene ethynylene); molecular wire; self-assembly; STM; topography; transport properties ID SELF-ASSEMBLED MONOLAYERS; NEGATIVE DIFFERENTIAL RESISTANCE; ELECTRONIC DEVICE; OLIGOMERS; SURFACES; GOLD AB Conjugated phenylene(ethynylene) molecular wires are of interest as potential candidates for molecular electronic devices. Scanning tunneling microscopic study of the topography and current-voltage (I-V) characteristics of self-assembled monolayers of two types of molecular wires are presented here. The study shows that the topography and I-Vs, for small scan voltages, of the two wires are quite similar and that the electronic and structural changes introduced by the substitution of an electronegative N atom in the central phenyl ring of these wires does not significantly alter the self-assembly or the transport properties. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Dholakia, GR (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 16 TC 2 Z9 2 U1 0 U2 5 PU AMER SCIENTIFIC PUBLISHERS PI VALENCIA PA 26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA SN 1533-4880 J9 J NANOSCI NANOTECHNO JI J. Nanosci. Nanotechnol. PD JUN PY 2003 VL 3 IS 3 BP 231 EP 234 DI 10.1166/jnn.2003.188 PG 4 WC Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 716CR UT WOS:000185011700006 PM 14503407 ER PT J AU Vander Wal, RL Berger, GM Ticich, TM AF Vander Wal, RL Berger, GM Ticich, TM TI Carbon nanotube synthesis in a flame with independently prepared laser-ablated catalyst particles SO JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY LA English DT Article DE carbon nanotubes; flame; synthesis; catalysis; nanofibers ID DEPOSITION; HYDROGEN; NANOPARTICLES; NANOFIBERS AB Laser ablation flame. By prior synthesis of the metal nanoparticles, the effects of the reactive gases can be clearly separated from the pyrolysis chemistry of a solvent carrier, as when nebulized solutions are used. Moreover, varying reactivity issues associated with particle growth and size are bypassed. Our results show that Fe selectively reacts with CO to produce nanotubes, whereas Ni selectively reacts with C2H2 to produce nanofibers. These observations are interpreted through the donation and withdrawal of electron density between the adsorbate's molecular orbitals and surface atoms of the metal nanoparticle. The rate of reaction of Ni with only C2H2 is found to be greater than the rate with C2H2 and CO. This suggests that CO inhibits the Ni-catalyzed reaction. C1 NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. Centenary Coll Louisiana, Dept Chem, Shreveport, LA USA. RP Vander Wal, RL (reprint author), NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. NR 27 TC 6 Z9 6 U1 0 U2 5 PU AMER SCIENTIFIC PUBLISHERS PI STEVENSON RANCH PA 25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA SN 1533-4880 J9 J NANOSCI NANOTECHNO JI J. Nanosci. Nanotechnol. PD JUN PY 2003 VL 3 IS 3 BP 241 EP 245 DI 10.1166/jnn.2003.201 PG 5 WC Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 716CR UT WOS:000185011700008 PM 14503409 ER PT J AU Matsko, AB Savchenkov, AA Letargat, RJ Ilchenko, VS Maleki, L AF Matsko, AB Savchenkov, AA Letargat, RJ Ilchenko, VS Maleki, L TI On cavity modification of stimulated Raman scattering SO JOURNAL OF OPTICS B-QUANTUM AND SEMICLASSICAL OPTICS LA English DT Article DE cavity QED; whispering gallery modes; stimulated Raman scattering ID MICROMETER-SIZE DROPLETS; BEAM-SHAPE COEFFICIENTS; LORENZ-MIE THEORY; QUANTUM ELECTRODYNAMICS; LOCALIZED APPROXIMATION; RIGOROUS JUSTIFICATION; SPONTANEOUS EMISSION; MICROWAVE RECEIVER; OPTICAL FIBERS; AXIS BEAMS AB We study theoretically stimulated Raman scattering (SRS) in a nonlinear dielectric microcavity and compare SRS thresholds for the cavity and the bulk material it is made of. We show that cavity SRS enhancement results solely from the intensity build up in the cavity and from the differences of the SRS dynamics in free and confined space. There is no significant modification of the Raman gain due to cavity QED effects. We show that the SRS threshold depends significantly on the nature of the dominating cavity decay as well as on the coupling technique with the cavity used for SRS measurements. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Matsko, AB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Matsko, Andrey/A-1272-2007 NR 48 TC 25 Z9 26 U1 0 U2 7 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 2003 VL 5 IS 3 BP 272 EP 278 AR PII S1464-4266(03)57416-X DI 10.1088/1464-4266/5/3/312 PG 7 WC Optics; Physics, Applied SC Optics; Physics GA 699LY UT WOS:000184059400014 ER PT J AU Smart, MC Ratnakumar, BV Whitcanack, LD Chin, KB Surampudi, S Croft, H Tice, D Staniewicz, R AF Smart, MC Ratnakumar, BV Whitcanack, LD Chin, KB Surampudi, S Croft, H Tice, D Staniewicz, R TI Improved low-temperature performance of lithium-ion cells with quaternary carbonate-based electrolytes SO JOURNAL OF POWER SOURCES LA English DT Article; Proceedings Paper CT 11th International Meeting on Lithium Batteries CY JUN 24-28, 2002 CL MONTEREY, CALIFORNIA DE low-temperature performance; lithium-ion cells; carbonate-based electrolytes ID BATTERIES; MIXTURES AB in order to enable future missions involving the exploration of the surface of Mars with Landers, and Rovers, NASA desires long life, high energy density rechargeable batteries which can operate well at very low temperature (down to -40 degreesC). Lithium-ion technology has been identified as being the most promising chemistry, due to high gravimetric and volumetric energy densities, as well as, long life characteristics. However, the state-of-art (SOA) technology is not sufficient to meet the needs of many applications that require excellent low-temperature capabilities. To further improve this technology, work at JPL has been focused upon developing electrolytes that result in lithium-ion cells with wider temperature ranges of operation. These efforts have led to the identification of a number of ternary and quaternary, all carbonate-based electrolytes that have been demonstrated to result in improved low-temperature performance in experimental three-electrode MCMB-carbon/LiNi0.8Co0.2O2 cells. A number of electrochemical characterization techniques were performed on these cells (i.e. Tafel polarization measurements, linear polarization measurements, and electrochemical impedance spectroscopy (EIS)) to further enhance our understanding of the performance limitations at low temperature. The most promising electrolyte formulations, namely 1.0 M LiPF6 EC + DEC + DMC + EMC (1: 1: 1:2 v/v) and 1.0 M LiPF6 EC + DEC + DMC + EMC (1:1:1:3 v/v), were incorporated into SAFT prototype DD-size (9 Ah) lithium-ion cells for evaluation. A number of electrical tests were performed on these cells, including rate characterization as a function of temperature, cycle life characterization at different temperatures, as well as, many mission specific characterization tests to determine their viability to enable future missions to Mars. Excellent performance was observed with the prototype DD-size cells over a wide temperature range (-50 to 40 degreesC), with high specific energy being delivered at very low temperatures (i.e. over 95 Wh/kg being delivered at -40 degreesC using a C/10 discharge rate). (C) 2003 Elsevier Science B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. SAFT Amer Inc, Battery Res & Dev Facil, Cockeysville, MD 20130 USA. RP Smart, MC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 25 TC 63 Z9 74 U1 5 U2 51 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD JUN 1 PY 2003 VL 119 SI SI BP 349 EP 358 DI 10.1016/S0378-7753(03)00154-X PG 10 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 694XC UT WOS:000183799600067 ER PT J AU Smart, MC Ratnakumar, BV Ryan-Mowrey, VS Surampudi, S Prakash, GKS Hub, J Cheung, I AF Smart, MC Ratnakumar, BV Ryan-Mowrey, VS Surampudi, S Prakash, GKS Hub, J Cheung, I TI Improved performance of lithium-ion cells with the use of fluorinated carbonate-based electrolytes SO JOURNAL OF POWER SOURCES LA English DT Article; Proceedings Paper CT 11th International Meeting on Lithium Batteries CY JUN 24-28, 2002 CL MONTEREY, CALIFORNIA DE lithium-ion cells; fluorinated carbonate-based electrolytes; performance ID CHLOROETHYLENE CARBONATE; BATTERIES; SOLVENT; ANODE AB There has been increasing interest in developing lithium-ion electrolytes that possess enhanced safety characteristics, while still able to provide the desired stability and performance. Toward this end, our efforts have been focused on the development of lithium-ion electrolytes which contain partially and fully fluorinated carbonate solvents. The advantage of using such solvents is that they possess the requisite stability demonstrated by the hydrocarbon-based carbonates, while also possessing more desirable physical properties imparted by the presence of the fluorine substituents, such as lower melting points, increased stability toward oxidation, and favorable SEI film forming characteristics on carbon. Specifically, we have demonstrated the beneficial effect of electrolytes which contain the following fluorinated catbonate-based solvents: methyl-2,2,2-trifluoroethyl carbonate (MTFEC), ethyl-2,2,2-trifluoroethyl carbonate (ETFEC), propyl-2,2,2trifluoroethyl carbonate (PTFEC), methyl-2,2,2,2',2',2'-hexafluoro-i-propyl carbonate (MHFPC), ethyl-2,2,2,2',2',2'-hexafluoro-i-propyI carbonate (EHFPC), and di-2,2,2-trifluoroethyl carbonate (DTFEC). These solvents have been incorporated into multi-component ternary and quaternary carbonate-based electrolytes and evaluated in lithium-carbon and carbon-LiNi0.8Co0.2O2 cells (equipped with lithium reference electrodes). In addition to determining the charge/discharge behavior of these cells, a number of electrochemical techniques were employed (i.e. Tafel polarization measurements, linear polarization measurements, and electrochemical impedance spectroscopy (EIS)) to further characterize the performance of these electrolytes, including the SEI formation characteristics and lithium intercalation/deintercalation kinetics. (C) 2003 Elsevier Science B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ So Calif, Loker Hydrocarbon Res Inst, Los Angeles, CA USA. RP Smart, MC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 55 Z9 59 U1 5 U2 34 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD JUN 1 PY 2003 VL 119 SI SI BP 359 EP 367 DI 10.1016/S0378-7753(03)00266-0 PG 9 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 694XC UT WOS:000183799600068 ER PT J AU Ratnakumar, BV Smart, MC Kindler, A Frank, H Ewell, R Surampudi, S AF Ratnakumar, BV Smart, MC Kindler, A Frank, H Ewell, R Surampudi, S TI Lithium batteries for aerospace applications: 2003 Mars Exploration Rover SO JOURNAL OF POWER SOURCES LA English DT Article; Proceedings Paper CT 11th International Meeting on Lithium Batteries CY JUN 24-28, 2002 CL MONTEREY, CALIFORNIA DE Mars Exploration Rover; Martian rocks; Mars pathfinder ID ION BATTERIES; ELECTROLYTES; PERFORMANCE; NASA AB Future NASAs planetary exploration missions require batteries that can operate at extreme temperatures and deliver high specific energy and energy densities. Conventional aerospace rechargeable battery systems, such as Ni-Cd, Ni-H-2 and Ag-Zn, are inadequate to meet these demands. Lithium ion rechargeable batteries were therefore chosen as the baseline for these missions. The 2003 Mars Exploration Rover (MER) mission plans to deploy twin rovers onto Mars, with the objectives of understanding its geology, climate conditions and possibility of life on Mars. The spacecraft contain various batteries, i.e. primary batteries on the lander, thermal batteries on the back shell and rechargeable batteries on the Rovers. Significant among them are the Li ion rechargeable batteries, which are being utilized for the first time in a major NASA mission. The selection of the Li ion battery has been dictated by various factors, including mass and volume constraints, cycle life, and its ability to operate well at sub-zero temperatures (down to -30 degreesC), at moderate rates. This paper describes the selection criteria, design and performance of the three battery systems on 2003 MER mission. (C) 2003 Published by Elsevier Science B.V. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ratnakumar, BV (reprint author), CALTECH, Jet Prop Lab, M-S 277-207, Pasadena, CA 91109 USA. NR 13 TC 36 Z9 39 U1 1 U2 17 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD JUN 1 PY 2003 VL 119 SI SI BP 906 EP 910 DI 10.1016/S0378-7753(03)00220-9 PG 5 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 694XC UT WOS:000183799600169 ER PT J AU Hanner, MS AF Hanner, MS TI The scattering properties of cometary dust SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article; Proceedings Paper CT 6th International Conference on Electromagnetic and Light Scattering by Nonspherical Particles CY MAR 04-08, 2002 CL UNIV FLORIDA, GAINESVILLE, FL HO UNIV FLORIDA ID BOPP C/1995 O1; LIGHT-SCATTERING; HALE-BOPP; AGGREGATE PARTICLES; OPTICAL-PROPERTIES; PROGRA(2) EXPERIMENT; IMAGING POLARIMETRY; INTERSTELLAR DUST; WAVELENGTH; COMA AB The dust particles in different comets exhibit generally similar scattering properties. Polarization is characterized by a small negative branch at scattering angles theta > 160degrees and a maximum of 15-25% near 90degrees in red light. The material is, on average, very dark, with geometric albedo of 3-5% at visual to near-infrared wavelengths for comets within 2.5 AU of the sun. The scattering properties are consistent with a mixture of silicate and carbonaceous material, as measured by the Halley space probes. In comparing comets, there is a correlation of stronger polarization, redder polarimetric color, higher albedo, stronger infrared silicate emission, and higher infrared color temperature. Aggregate particles having constituent grain size parameters X greater than or equal to 1.5 show promise in matching the observed scattering properties. An enhancement in the abundance of small silicate grains with X similar to 1.5-2 at 0.5 mum wavelength may cause the higher polarization, higher albedo, and stronger silicate emission in comets such as Hale-Bopp. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Mail Stop 183-501, Pasadena, CA 91109 USA. EM msh@scn1.jpl.nasa.gov NR 43 TC 21 Z9 21 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 EI 1879-1352 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUN-SEP PY 2003 VL 79 SI SI BP 695 EP 705 AR PII S0022-4073(02)00315-1 DI 10.1016/S0022-4073(02)00315-1 PG 11 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 674QM UT WOS:000182647500014 ER PT J AU Hu, YX Yang, P Lin, B Gibson, G Hostetler, C AF Hu, YX Yang, P Lin, B Gibson, G Hostetler, C TI Discriminating between spherical and non-spherical scatterers with lidar using circular polarization: a theoretical study SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article; Proceedings Paper CT 6th International Conference on Electromagnetic and Light Scattering by Nonspherical Particles CY MAR 04-08, 2002 CL UNIV FLORIDA, GAINESVILLE, FL HO UNIV FLORIDA ID ICE CRYSTALS; LIGHT-SCATTERING; PHASE; DEPOLARIZATION; PARTICLES; RETURNS; CIRRUS; SHAPE AB For ground based observations, depolarization of lidar backscatter indicates that the scattering particles are non-spherical. This property provides a useful means to discriminate between ice particles (non-spherical) and water droplets (spherical) in clouds. However, for space based lidar measurements, backscatter from spherical water cloud particles is also depolarized due to multiple scattering. For the spaceborne lidar application, the discrimination between water and ice is not straightforward. An alternative method for water/ice discrimination that is less sensitive to multiple scattering is proposed in this study. The new approach is based on the differences in P-44 (an element of the scattering phase matrix) at 180degrees scattering angle between spherical and non-spherical particles. By transmitting a circularly polarized beam from the lidar and resolving the rotational sense of the polarization in the receiver, discrimination between spherical and non-spherical scatterers can be accomplished even when multiple scattering occurs. When the incident beam is left-hand-circularly polarized, the circular component of backscatter by a non-spherical particle is weak and possibly left-handed, whereas backscatter by a spherical particle is significantly right-hand-circularly polarized. Monte Carlo simulations with full Stokes vector parameterizations indicate that multiple scattering does not affect the rotational sense of the backscatter polarization, making robust discrimination between spheres and non-spheres possible with this new circular polarization approach. Published by Elsevier Science Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. RP NASA, Langley Res Ctr, MS 420, Hampton, VA 23681 USA. EM y.hu@larc.nasa.gov RI Yang, Ping/B-4590-2011; Hu, Yongxiang/K-4426-2012 NR 24 TC 21 Z9 22 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 EI 1879-1352 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUN-SEP PY 2003 VL 79 SI SI BP 757 EP 764 DI 10.1016/S0022-4073(02)00320-5 PG 8 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 674QM UT WOS:000182647500019 ER PT J AU Liu, L Mishchenko, MI Hovenier, JW Volten, H Munoz, O AF Liu, L Mishchenko, MI Hovenier, JW Volten, H Munoz, O TI Scattering matrix of quartz aerosols: comparison and synthesis of laboratory and Lorenz-Mie results SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article; Proceedings Paper CT 6th International Conference on Electromagnetic and Light Scattering by Nonspherical Particles CY MAR 04-08, 2002 CL UNIV FLORIDA, GAINESVILLE, FLORIDA HO UNIV FLORIDA DE electromagnetic scattering; nonspherical particles; polarization ID TROPOSPHERIC AEROSOLS; LIGHT-SCATTERING; POLYDISPERSE; PARTICLES; SPHEROIDS AB This paper compares and combines the results of laboratory measurements of the Stokes scattering matrix for nonspherical quartz aerosols at a visible wavelength in the scattering angle range 5-173degrees and the results of Lorenz-Mie computations for projected-area-equivalent spheres with the refractive index of quartz. A synthetic normalized phase function is constructed based on the laboratory data and the assumption that the diffraction forward-scattering peak is the same for spherical and nonspherical projected-area-equivalent particles. The experimental scattering matrix for the nonspherical quartz particles is poorly represented by the Lorenz-Mie results for most scattering angles. However, the asymmetry parameters for the synthetic phase function and for the equivalent spherical particles are similar. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Earth & Environm Sci, New York, NY 10025 USA. Free Univ Amsterdam, Dept Phys & Astron, NL-1081 HV Amsterdam, Netherlands. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. FOM, Inst Atom & Mol Phys, NL-1098 SJ Amsterdam, Netherlands. Inst Astrofis Andalucia, E-18080 Granada, Spain. RP Mishchenko, MI (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. RI Mishchenko, Michael/D-4426-2012; OI Munoz, Olga/0000-0002-5138-3932 NR 25 TC 44 Z9 45 U1 0 U2 4 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-SEP PY 2003 VL 79 SI SI BP 911 EP 920 DI 10.1016/S0022-4073(02)00328-X PG 10 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 674QM UT WOS:000182647500028 ER PT J AU Mishchenko, MI Geogdzhayev, IV Liu, L Ogren, JA Lacis, AA Rossow, WB Hovenier, JW Volten, H Munoz, O AF Mishchenko, MI Geogdzhayev, IV Liu, L Ogren, JA Lacis, AA Rossow, WB Hovenier, JW Volten, H Munoz, O TI Aerosol retrievals from AVHRR radiances: effects of particle nonsphericity and absorption and an updated long-term global climatology of aerosol properties SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article; Proceedings Paper CT 6th International Conference on Electromagnetic and Light Scattering by Nonspherical Particles CY MAR 04-08, 2002 CL UNIV FLORIDA, GAINESVILLE, FLORIDA HO UNIV FLORIDA DE atmospheric aerosols; nonspherical particles; remote sensing ID TROPOSPHERIC AEROSOLS; OPTICAL DEPTH; LIGHT-SCATTERING; OCEAN; CLOUDS; POLYDISPERSE; SENSITIVITY; INFORMATION; VALIDATION; ALGORITHM AB The paper describes and discusses long-term global retrievals of aerosol properties from channel-1 and -2 Advanced Very High-Resolution Radiometer (AVHRR) radiances. We reconfirm the previously reached conclusion that the nonsphericity of dust-like and dry sea salt aerosols can lead to very large errors in the retrieved optical thickness if one mistakenly applies the scattering model for spherical particles. Comparisons of single-scattering albedo and Angstrom exponent values retrieved from the AVHRR data and those measured in situ at Sable Island indicate that the currently adopted value 0.003 can be a reasonable choice for the imaginary part of the aerosol refractive index in the global satellite retrievals. Several unexpected features in the long-term satellite record indicate a serious problem with post-launch calibration of channel-2 radiances from the NOAA-11 spacecraft. We solve this problem by using a simple re-calibration procedure removing the observed artifacts and derive a global climatology of aerosol optical thickness and size over the oceans for the period extending from July 1983 to December 1999. The global monthly mean optical thickness and Angstrom exponent of tropospheric aerosols show no significant trends over the entire period and oscillate around the average values 0.145 and 0.75, respectively. The Northern Hemisphere mean optical thickness systematically exceeds that averaged over the Southern Hemisphere. The AVHRR retrieval results during the period affected by the Mt. Pinatubo eruption are consistent with the retrievals of the stratospheric aerosol optical thickness based on Stratospheric Aerosol and Gas Experiment data (SAGE). Time series of the aerosol optical thickness and Angstrom exponent derived for four separate geographic regions exhibit varying degrees of seasonal variability controlled by local meteorological events and/or anthropogenic activities. (C)2003 Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10025 USA. Columbia Univ, Dept Earth & Environm Sci, New York, NY 10025 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO USA. Free Univ Amsterdam, Dept Phys & Astron, NL-1081 HV Amsterdam, Netherlands. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. FOM, Inst Atom & Mol Phys, NL-1098 SJ Amsterdam, Netherlands. Inst Astrofis Andalucia, E-18080 Granada, Spain. RP Mishchenko, MI (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. RI Lacis, Andrew/D-4658-2012; Rossow, William/F-3138-2015; Mishchenko, Michael/D-4426-2012; Ogren, John/M-8255-2015; OI Ogren, John/0000-0002-7895-9583; Munoz, Olga/0000-0002-5138-3932 NR 40 TC 81 Z9 82 U1 0 U2 4 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-SEP PY 2003 VL 79 SI SI BP 953 EP 972 DI 10.1016/S0022-4073(02)00331-X PG 20 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 674QM UT WOS:000182647500031 ER PT J AU Yang, P Hu, YX Winker, DM Zhao, J Hostetler, CA Poole, L Baum, BA Mishchenko, MI Reichardt, J AF Yang, P Hu, YX Winker, DM Zhao, J Hostetler, CA Poole, L Baum, BA Mishchenko, MI Reichardt, J TI Enhanced lidar backscattering by quasi-horizontally oriented ice crystal plates in cirrus clouds SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article; Proceedings Paper CT 6th International Conference on Electromagnetic and Light Scattering by Nonspherical Particles CY MAR 04-08, 2002 CL UNIV FLORIDA, GAINESVILLE, FL HO UNIV FLORIDA DE lidar; backscattering; ice plates; cirrus clouds ID DIFFERENCE TIME-DOMAIN; OPTICAL-PROPERTIES; SINGLE-SCATTERING; LIGHT-SCATTERING; PARTICLES; MATRIX; PHASE; SPACE AB The backscattering of light by quasi-horizontally oriented hexagonal ice plates is investigated because of its pertinence to lidar measurements of cirrus clouds. For oriented ice crystals, the commonly used geometric optics ray-tracing method is not applicable to the computation of the scattered field in certain scattering directions, in particular, the backscattering direction, because of the singularity problem inherent to the ray-tracing technique. In this study, we solve for the electric field due to scattering by quasi-horizontally oriented ice plates using an approach based on the electromagnetic wave theory. We simplify the analysis by ignoring the effect of the plate's side faces on the internal field inside the particle. This is a reasonable approximation when the ratio of the particle diameter to its thickness is large. This approximation is also valid if the tilt of the particle's symmetric axis from zenith is small and the size parameter is large. The present numerical results indicate that very strong oscillations in the backscattering cross section occur with the variation of size parameter. Furthermore, the bulk backscattering intensity has been calculated by including the effect of a particle size distribution and the random tilt of particle symmetric axis within a small angular region, for example, 2degrees. A strong dependence is found between the lidar backscattering cross section and the degree of the random tilt of the particles. A combination of the present method with the T-matrix method, which works well for particles having small and moderate size parameters, may provide a more complete picture of the lidar backscattering by quasi-horizontally oriented ice plates. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Texas A&M Univ, Dept Math, College Stn, TX 77843 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Maryland Baltimore Cty, JCET, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Texas A&M Univ, Dept Atmospher Sci, TAMU 3150, College Stn, TX 77843 USA. EM pyang@ariel.met.tamu.edu RI Yang, Ping/B-4590-2011; Baum, Bryan/B-7670-2011; Hu, Yongxiang/K-4426-2012; Mishchenko, Michael/D-4426-2012 OI Baum, Bryan/0000-0002-7193-2767; NR 22 TC 13 Z9 13 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 EI 1879-1352 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUN-SEP PY 2003 VL 79 SI SI BP 1139 EP 1157 DI 10.1016/S0022-4073(02)00346-1 PG 19 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 674QM UT WOS:000182647500046 ER PT J AU Yang, P Baum, BA Heymsfield, AJ Hu, YX Huang, HL Tsay, SC Ackerman, S AF Yang, P Baum, BA Heymsfield, AJ Hu, YX Huang, HL Tsay, SC Ackerman, S TI Single-scattering properties of droxtals SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article; Proceedings Paper CT 6th International Conference on Electromagnetic and Light Scattering by Nonspherical Particles CY MAR 04-08, 2002 CL UNIV FLORIDA, GAINESVILLE, FLORIDA HO UNIV FLORIDA DE small ice crystals; droxtals; optical properties ID ICE CRYSTALS; BIDIRECTIONAL REFLECTANCE; LIGHT-SCATTERING; SENSITIVITY; PARTICLES; SHAPE AB Small ice crystals have been found to occur in high concentrations in polar stratospheric clouds and the upper portion of cirrus clouds, where temperatures are extremely low (often less than -50degreesC). The scattering properties of these small crystals are important to space-borne remote sensing, especially for the retrieval of cirrus properties using visible and near-infrared channels. Previous research has shown that the commonly used spherical and "quasi-spherical" approximations for these ice crystals can lead to significant errors in light scattering and radiative transfer calculations. We suggest that droxtals more accurately represent the shape of these small ice crystals. The single-scattering properties of ice droxtals have been computed at visible and infrared wavelengths using the finite-difference time domain method for size parameters smaller than 20. Further study of the optical properties of larger droxtals (size parameter greater than 20) will be carried out using an improved geometric optics method. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Natl Ctr Atmospher Res, Boulder, CO USA. Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Yang, P (reprint author), Texas A&M Univ, Dept Atmospher Sci, TAMU 3150, College Stn, TX 77843 USA. RI Yang, Ping/B-4590-2011; Baum, Bryan/B-7670-2011; Heymsfield, Andrew/E-7340-2011; Ackerman, Steven/G-1640-2011; Tsay, Si-Chee/J-1147-2014; Hu, Yongxiang/K-4426-2012 OI Baum, Bryan/0000-0002-7193-2767; Ackerman, Steven/0000-0002-4476-0269; NR 16 TC 78 Z9 82 U1 0 U2 3 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-SEP PY 2003 VL 79 SI SI BP 1159 EP 1169 DI 10.1016/S0022-4073(02)00347-3 PG 11 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 674QM UT WOS:000182647500047 ER PT J AU Yang, P Wei, HL Baum, BA Huang, HL Heymsfield, AJ Hu, YX Gao, BC Turner, DD AF Yang, P Wei, HL Baum, BA Huang, HL Heymsfield, AJ Hu, YX Gao, BC Turner, DD TI The spectral signature of mixed-phase clouds composed of non-spherical ice crystals and spherical liquid droplets in the terrestrial window region SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article; Proceedings Paper CT 6th International Conference on Electromagnetic and Light Scattering by Nonspherical Particles CY MAR 04-08, 2002 CL UNIV FLORIDA, GAINESVILLE, FLORIDA HO UNIV FLORIDA DE mixed-phase clouds; single-scattering parameters; infrared; high-resolution spectral signature ID RADIATIVE PROPERTIES; OPTICAL-PROPERTIES; CIRRUS CLOUDS; SCATTERING; ABSORPTION; MIDLATITUDE; ALGORITHM AB An outstanding problem facing the cloud modeling and remote sensing community is to improve satellite-derived cloud microphysical and macrophysical properties when a single cloud layer exists within a temperature range for which a combination of water and ice particles may be present. This is typically known as a "mixed-phase" cloud condition, and is prevalent when the cloud-top temperature lies between -40degreesC and 0degreesC. In this paper we report on a sensitivity study of the spectral signature of mixed-phase clouds in the infrared terrestrial window region (8-13 mum). Mixed clouds are assumed to be a vertically uniform cloud layer composed of a mixture of pristine hexagonal ice crystals and spherical water droplets. Unlike the conventional approach that derives the bulk scattering properties of mixed-phase clouds by a linear weighting of the contributions of ice and water components, the bulk single-scattering properties of mixed-phase clouds are formulated on the basis of fundamental physics. With the aid of a line-by-line radiative transfer model and a discrete ordinates radiative transfer (DISORT) computational program, we investigate the high-resolution spectral signature, expressed in terms of brightness temperature, of mixed-phase clouds with various effective sizes, ice fraction ratios, and optical thicknesses. Small particles are found to have a significant impact on the infrared spectral signature of mixed-phase clouds when the size discrepancy between the ice and water particles is large. Furthermore, the simulation results show that the infrared radiative spectrum associated with cirrus clouds can be quite different from their counterparts for cirrus clouds even if a small amount of water droplets exist in the mixed-phase cloud layer. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53706 USA. Natl Ctr Atmospher Res, Boulder, CO USA. USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. RP Yang, P (reprint author), Texas A&M Univ, Dept Atmospher Sci, TAMU 3150, College Stn, TX 77843 USA. RI Yang, Ping/B-4590-2011; Baum, Bryan/B-7670-2011; Heymsfield, Andrew/E-7340-2011; Hu, Yongxiang/K-4426-2012 OI Baum, Bryan/0000-0002-7193-2767; NR 35 TC 22 Z9 23 U1 0 U2 7 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-SEP PY 2003 VL 79 SI SI BP 1171 EP 1188 DI 10.1016/S0022-4073(02)00348-5 PG 18 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 674QM UT WOS:000182647500048 ER PT J AU Anderson, MS Gaimari, SD AF Anderson, MS Gaimari, SD TI Raman-atomic force microscopy of the ommatidial surfaces of Dipteran compound eyes SO JOURNAL OF STRUCTURAL BIOLOGY LA English DT Article DE AFM; brachycera; Diptera; nematocera; ommatidia; Raman; systematics ID SPECTROSCOPY; BRACHYCERA AB The ommatidial lens surfaces of the compound eyes in several species of flies (Insecta: Diptera) and a related order (Mecoptera) were analyzed using a recently developed Raman-atomic force microscope. We demonstrate in this work that the atomic force microscope (AFM) is a potentially useful instrument for gathering phylogenetic data and that the newly developed Raman-AFM may extend this application by revealing nanometer-scale surface chemistry. This is the first demonstration of apertureless near-field Raman spectroscopy on an intact biological surface. For Chrysopilus testaceipes Bigot (Rhagionidae), this reveals unique cerebral cortex-like surface ridges with periodic variation in height and surface chemistry. Most other Brachyceran flies, and the "Nematoceran" Sylvicola fenestralis (Scopoli) (Anisopodidae), displayed the same morphology, while other taxa displayed various other characteristics, such as a nodule-like (Tipula (Triplicitipula) sp. (Tipulidae)) or coalescing nodule-like (Tabanus punctifer Osten Sacken (Tabanidae)) morphology, a smooth morphology with distinct pits and grooves (Dilophus orbatus (Say) (Bibionidae)), or an entirely smooth surface (Bittacus chlorostigma MacLachlan (Mecoptera: Bittacidae)). The variation in submicrometer structure and surface chemistry provides a new information source of potential phylogenetic importance, suggesting the Raman-atomic force microscope could provide a new tool useful to systematic and evolutionary inquiry. (C) 2003 Elsevier Science (USA). All rights reserved. C1 CALTECH, Jet Prop Lab, Chem Anal & Mat Dev Grp, Pasadena, CA 91109 USA. Calif Dept Food & Agr, Plant Pest Diagnost Branch, Calif State Collect Arthropods, Sacramento, CA 95814 USA. RP Anderson, MS (reprint author), CALTECH, Jet Prop Lab, Chem Anal & Mat Dev Grp, 4800 Oak Grove Dr,MS 125-109, Pasadena, CA 91109 USA. NR 19 TC 24 Z9 24 U1 1 U2 9 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1047-8477 J9 J STRUCT BIOL JI J. Struct. Biol. PD JUN PY 2003 VL 142 IS 3 BP 364 EP 368 DI 10.1016/S1047-8477(03)00026-1 PG 5 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 689PK UT WOS:000183502000005 PM 12781663 ER PT J AU Norton, GV Novarini, JC AF Norton, GV Novarini, JC TI Including dispersion and attenuation directly in the time domain for wave propagation in isotropic media SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article; Proceedings Paper CT 143rd Annual Meeting of the Acoustical Society of America CY JUN 03-07, 2002 CL PITTSBURGH, PENNSYLVANIA SP Acoust Soc Amer ID SOUND; EQUATIONS; PHASE AB When sound propagates in a lossy fluid, causality dictates that in most cases the presence of attenuation is accompanied by dispersion. The ability to incorporate attenuation and its causal companion, dispersion, directly in the time domain has received little attention. Szabo [J. Acoust. Soc. Am. 96, 491-500 (1994)] showed that attenuation and dispersion in a linear medium can be accounted for in the linear wave equation by the inclusion of a causal convolutional propagation operator that includes both phenomena. Szabo's work was restricted to media with a power-law attenuation. Waters et al. [J. Acoust. Soc. Am 108, 2114-2119 (2000)] showed that Szabo's approach could be used in a broader class of media, Direct application of Szabo's formalism is still lacking. To evaluate the concept of the causal convolutional propagation operator as introduced by Szabo, the operator is applied to pulse propagation in an isotropic lossy medium directly in the time domain. The generalized linear wave equation containing the operator is solved via a finite-difference-time-domain scheme. Two functional forms for the attenuation often encountered in acoustics are examined. It is shown that the presence of the operator correctly incorporates both, attenuation and dispersion. (C) 2003 Acoustical Society of America. C1 USN, Res Lab, Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. Planning Syst Inc, Long Beach, MS 39560 USA. RP Norton, GV (reprint author), USN, Res Lab, Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. NR 14 TC 33 Z9 35 U1 0 U2 2 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 JUN PY 2003 VL 113 IS 6 BP 3024 EP 3031 DI 10.1121/1.1572143 PG 8 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 688RB UT WOS:000183448700010 PM 12822773 ER PT J AU Zuckerwar, AJ Kuhn, TR Serbyn, RM AF Zuckerwar, AJ Kuhn, TR Serbyn, RM TI Background noise in piezoresistive, electret condenser, and ceramic microphones SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article; Proceedings Paper CT 143rd Annual Meeting of the Acoustical Society of America CY JUN 03-07, 2002 CL PITTSBURGH, PENNSYLVANIA SP Acoust Soc Amer AB Background noise studies have been extended from air condenser microphones to piezoresistive, electret condenser, and ceramic microphones. Theoretical models of the respective noise sources within each microphone are developed and are used to derive analytical expressions for the noise power spectral density for each type. Several additional noise sources for the piezoresistive and electret microphones, beyond what had previously been considered, were applied to the models and were found to contribute significantly to the total noise, power spectral density. Experimental background noise measurements were taken using an upgraded acoustic isolation vessel and data acquisition system, and the results were compared to the theoretically obtained expressions. The models were found to yield power spectral densities consistent with the experimental results. The measurements reveal that the 1/f noise coefficient is strongly correlated with the diaphragm damping resistance, irrespective of the detection technology, i.e., air condenser, piezoresistive, etc. This conclusion has profound implications upon the expected 1/f noise component of micromachined (MEMS) microphones. (C) 2003 Acoustical Society of America. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Morgan State Univ, Dept Phys, Baltimore, MD 21251 USA. RP Zuckerwar, AJ (reprint author), NASA, Langley Res Ctr, Mail Stop 493, Hampton, VA 23681 USA. NR 11 TC 11 Z9 11 U1 0 U2 2 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 JUN PY 2003 VL 113 IS 6 BP 3179 EP 3187 DI 10.1121/1.1572147 PG 9 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 688RB UT WOS:000183448700027 PM 12822790 ER PT J AU Kirkpatrick, AW Hamilton, DR Nicolaou, S Sargsyan, AE Campbell, MR Feiveson, A Dulchavsky, SA Melton, S Beck, G Dawson, DL AF Kirkpatrick, AW Hamilton, DR Nicolaou, S Sargsyan, AE Campbell, MR Feiveson, A Dulchavsky, SA Melton, S Beck, G Dawson, DL TI Focused assessment with sonography for trauma in weightlessness: A feasibility study SO JOURNAL OF THE AMERICAN COLLEGE OF SURGEONS LA English DT Article; Proceedings Paper CT 74th Annual Scientific Meeting of the Aerospace-Medical-Society CY MAY, 2003 CL SAN ANTONIO, TEXAS SP Aerospace med Soc ID BLUNT ABDOMINAL-TRAUMA; SURGICAL INVESTIGATIONS; PHYSICAL-EXAMINATION; ENDOSCOPIC SURGERY; IN-SPACE; MICROGRAVITY; ULTRASOUND; ULTRASONOGRAPHY; INJURY; CARE AB BACKGROUND: The Focused Assessment with Sonography for Trauma (FAST) examines for fluid in gravitationally dependent regions. There is no prior experience with this technique in weightlessness, such as on the International Space Station, where sonography is currently the only diagnostic imaging tool. STUDY DESIGN: A ground-based (I g) porcine model for sonography was developed. We examined both the feasibility and the comparative performance of the FAST examination in parabolic flight. Sonographic detection and fluid behavior were evaluated in four animals during alternating weightlessness (0 g) and hypergravicy (1.8 g) periods. During flight, boluses of fluid were incrementally introduced into the peritoneal cavity. Standardized sonographic windows were recorded. Postflight, the video recordings were divided into 169 20-second segments for subsequent interpretation by 12 blinded ultrasonography experts. Reviewers first decided whether a video segment was of sufficient diagnostic quality to analyze (determinate). Determinate segments were then analyzed as containing or not containing fluid. A probit regression model compared the probability of a positive fluid diagnosis to actual fluid levels (0 to 500 mL) under both 0-g and 1.8-g conditions. RESULTS: The in-flight sonographers found real-time scanning and interpretation technically similar to that of terrestrial conditions, as long as restraint was maintained. On blinded review, 80% of the recorded ultrasound segments were considered determinate. The best sensitivity for diagnosis in 0 g was found to be from the subhepatic space, with probability of a positive fluid diagnosis ranging from 9% (no fluid) to 51% (500 mL fluid). CONCLUSIONS: The FAST examination is technically feasible in weightlessness, and merits operational consideration for clinical contingencies in space. (C) 2003 by the American College of Surgeons. C1 Foothills Med Ctr, Calgary, AB, Canada. Wyle Life Sci, Houston, TX USA. Vancouver Gen Hosp, Vancouver, BC, Canada. Natl Aeronaut & Space Adm, Space Life Sci Directorate, Houston, TX USA. Wayne State Univ, Detroit, MI USA. RP Kirkpatrick, AW (reprint author), 15 Coach Gate Way SW, Calgary, AB T3H 1L7, Canada. NR 51 TC 28 Z9 29 U1 0 U2 1 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 JUN PY 2003 VL 196 IS 6 BP 833 EP 844 DI 10.1016/S1072-7515(02)01906-3 PG 12 WC Surgery SC Surgery GA 685TV UT WOS:000183280100001 PM 12788418 ER PT J AU Kohel, JM Ramirez-Serrano, J Thompson, RJ Maleki, L AF Kohel, JM Ramirez-Serrano, J Thompson, RJ Maleki, L TI Generation of an intense cold-atom beam from a pyramidal magneto-optical trap: experiment and simulation SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID CESIUM ATOMS; SLOW ATOMS; VAPOR-CELL; FUNNEL; FORCE AB An intense cold-atom beam source based on a modified pyramidal magneto-optical trap has been developed and characterized. We have produced a slow beam of cold cesium atoms with a continuous flux of 2.2 X 10(9) atoms/s at a mean velocity of 15 m/s and with a divergence of 15 mrad. The corresponding radiant intensity is 1.2 X 10(13) atom s(-1) sr(-1). We have characterized the performance of our beam source over a range of operating conditions; and the measured values for atom flux, mean velocity, and divergence are in good agreement with results from detailed Monte Carlo numerical simulations. (C) 2003 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Dept Phys, Norman Bridge Lab, Pasadena, CA 91125 USA. RP Kohel, JM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Libbrecht, Kenneth/0000-0002-8744-3298 NR 19 TC 17 Z9 21 U1 1 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD JUN PY 2003 VL 20 IS 6 BP 1161 EP 1168 DI 10.1364/JOSAB.20.001161 PG 8 WC Optics SC Optics GA 687DQ UT WOS:000183361100001 ER PT J AU Barnes, NP Walsh, BM Filer, ED AF Barnes, NP Walsh, BM Filer, ED TI Ho : Ho upconversion: applications to Ho lasers SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID TM LASERS; YAG LASER; CRYSTALS; YLF AB Ho:Ho upconversion rates are predicted with a quantum-mechanical model and measured with a Q-switched Co:MgF2 laser to directly excite the Ho I-5(7) manifold. If Ho:Ho upconversion is low compared with spontaneous decay, Q-switched, Ho-only lasers can store energy efficiently over long time intervals. In this case, Ho-only lasers, when pumped by long-pulse-length Tm-only lasers, have great potential. Ho-only lasers have proven to be efficient, and, when long pump pulses are used, fewer laser diodes are required. To assess the Ho laser potential, Ho:Ho upconversion. parameters are calculated and measured for several Ho laser materials including Ho:YAG and Ho:YLF. The effects of both nonuniform pump energy deposition and diffusion of the excited Ho distribution are analyzed. (C) 2003 Optical Society of America. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Sci Applicat Int Corp, Hampton, VA 23680 USA. RP Barnes, NP (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 25 TC 45 Z9 46 U1 1 U2 16 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD JUN PY 2003 VL 20 IS 6 BP 1212 EP 1219 DI 10.1364/JOSAB.20.001212 PG 8 WC Optics SC Optics GA 687DQ UT WOS:000183361100007 ER PT J AU Ilchenko, VS Matsko, AB Savchenkov, AA Maleki, L AF Ilchenko, VS Matsko, AB Savchenkov, AA Maleki, L TI Low-threshold parametric nonlinear optics with quasi-phase-matched whispering-gallery modes SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID PERIODICALLY POLED LINBO3; MICROWAVE RECEIVER; LITHIUM-NIOBATE; MODULATOR; MICRODROPLETS; RESONANCES AB We propose to fabricate a toroidal dielectric cavity from a periodically poled chi((2)) nonlinear material (e.g., LiNbO3) to achieve efficient interaction among. high-Q whispering-gallery modes. We show that the periodic poling allows for suppression of both material and cavity dispersion. Such a cavity might be a basic element of a family of efficient nonlinear devices operating at a broad range of optical wavelengths. (C) 2003 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ilchenko, VS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Matsko, Andrey/A-1272-2007 NR 22 TC 44 Z9 44 U1 0 U2 9 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD JUN PY 2003 VL 20 IS 6 BP 1304 EP 1308 DI 10.1364/JOSAB.20.001304 PG 5 WC Optics SC Optics GA 687DQ UT WOS:000183361100018 ER PT J AU Kabir, HRH Al-Khaleefi, AM Diab, G AF Kabir, HRH Al-Khaleefi, AM Diab, G TI Application of Lagrange multiplier method to rectangular all-edge clamped plates SO KUWAIT JOURNAL OF SCIENCE & ENGINEERING LA English DT Article DE thin plate; Lagrange multiplier; clamped rectangular plates ID BOUNDARY CONSTRAINT; LAMINATION AB An analytical form of a solution to the boundary-value problem of thin all-edge clamped rectangular plates of an isotropic material subjected to a uniform gravity loading is presented. A generalized solution technique developed by Kabir and Chaudhuri (1992) is further advanced to a thin plate boundary-value problem to solve three highly coupled second-order partial differential equations with constant coefficients resulting from the application of the First Order Shear Deformation Theory. The solution functions are selected in such a way that they satisfy the clamped boundary conditions in a manner similar to the Navier method. The Lagrange Multiplier Method is applied to the First Order Shear Deformation-based formulation for all-edge clamped boundary conditions in obtaining a thin plate response. The numerical results presented include deflection and bending moment characteristics, and variations of these quantities with respect to various aspect ratios. The numerical results obtained from the present study are compared with the available classical thin plate results, First Order Shear Deformation Theory-based analytical and finite element results. The limitations of the Lagrange Multiplier Method to the present application are also discussed. C1 Kuwait Univ, Dept Civil Engn, Kuwait 13060, Kuwait. USA, NASA, Engn & Anal Div, Kennedy Space Ctr, FL USA. Gulf Int Inspect Co, Safat 13110, Kuwait. RP Al-Khaleefi, AM (reprint author), Kuwait Univ, Dept Civil Engn, POB 5969, Kuwait 13060, Kuwait. NR 16 TC 0 Z9 0 U1 0 U2 0 PU ACADEMIC PUBLICATION COUNCIL PI KHALDIYA PA PO BOX 17225, KHALDIYA 72453, KUWAIT SN 1024-8684 J9 KUWAIT J SCI ENG JI Kuwait J. Sci. Eng. PD JUN PY 2003 VL 30 IS 1 BP 153 EP 173 PG 21 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 700LD UT WOS:000184112700012 ER PT J AU Pensinger, JF Croonquist, AP Liu, FC Larson, ME Chui, TC AF Pensinger, JF Croonquist, AP Liu, FC Larson, ME Chui, TC TI An overview of the low temperature microgravity physics facility capabilities SO LOW TEMPERATURE PHYSICS LA English DT Article; Proceedings Paper CT 3rd International Workshop on Low-Temperature Physics in Microgravity Environment CY AUG 12-18, 2002 CL RUSSIAN ACAD SCI, CHERNOGOLOVKA RES CTR, CHERNOGOLOVKA, RUSSIA HO RUSSIAN ACAD SCI, CHERNOGOLOVKA RES CTR ID LAMBDA-POINT; HELIUM; HEAT AB The Low Temperature Microgravity Physics Facility currently in the design phase is a multiple user and multiple flight facility intended to provide a long duration low temperature environment onboard the International Space Station. The Facility will provide a unique platform for scientific investigations requiring both low temperature and microgravity conditions. It will be attached to the Japanese Experiment Module's Exposed Facility and can house two science instruments each flight. The Facility consists of a 180-liter superfluid helium dewar, a support enclosure, and control electronics. The facility will be launched full of cryogen, and retrieved after the cryogen is depleted. Industrial partners are responsible for building the reusable facility and standard parts of the instruments. Principal Investigators from universities and other institutions are contracted to develop major parts of the science instrument package. An overview of the detailed technical capabilities of the facility will be presented in this paper. (C) 2003 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Pensinger, JF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 1 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1063-777X J9 LOW TEMP PHYS+ JI Low Temp. Phys. PD JUN PY 2003 VL 29 IS 6 BP 461 EP 464 DI 10.1063/1.1542528 PG 4 WC Physics, Applied SC Physics GA 689HT UT WOS:000183486100003 ER PT J AU Strayer, DM Paik, HJ Moody, MV AF Strayer, DM Paik, HJ Moody, MV TI Short-range inverse-square law experiment in space SO LOW TEMPERATURE PHYSICS LA English DT Article; Proceedings Paper CT 3rd International Workshop on Low-Temperature Physics in Microgravity Environment CY AUG 12-18, 2002 CL RUSSIAN ACAD SCI, CHERNOGOLOVKA RES CTR, CHERNOGOLOVKA, RUSSIA HO RUSSIAN ACAD SCI, CHERNOGOLOVKA RES CTR ID GRAVITY; FORCES AB The objective of ISLES (inverse-square law experiment in space) is to perform a null test of Newton's law on the ISS with a resolution of one part in 10(5) at ranges from 100 mum to 1 mm. ISLES will be sensitive enough to detect axions with the strongest allowed coupling and to test the string-theory prediction with Rgreater than or equal to5 mum. To accomplish these goals on the rather noisy International Space Station, the experiment is set up to provide immunity from the vibrations and other common-mode accelerations. The measures to be applied for reducing the effects of disturbances will be described in this presentation. As designed, the experiment will be cooled to less than 2 K in NASA's low temperature facility the LTMPF, allowing superconducting magnetic levitation in microgravity to obtain very soft, low-loss suspension of the test masses. The low-damping magnetic levitation, combined with a low-noise SQUID, leads to extremely low intrinsic noise in the detector. To minimize Newtonian errors, ISLES employs a near-null source of gravity, a circular disk of large diameter-to-thickness ratio. Two test masses, also disk-shaped, are suspended on the two sides of the source mass at a distance of 100 mum to 1 mm. The signal is detected by a supercon-ducting differential accelerometer, making a highly sensitive sensor of the gravity force generated by the source mass. (C) 2003 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. RP Strayer, DM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 18 TC 0 Z9 0 U1 1 U2 3 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1063-777X J9 LOW TEMP PHYS+ JI Low Temp. Phys. PD JUN PY 2003 VL 29 IS 6 BP 472 EP 480 DI 10.1063/1.1542531 PG 9 WC Physics, Applied SC Physics GA 689HT UT WOS:000183486100006 ER PT J AU DellaCorte, C AF DellaCorte, C TI Coming soon to a mailbox near you SO LUBRICATION ENGINEERING LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Washington, DC 20546 USA. RP DellaCorte, C (reprint author), NASA, Glenn Res Ctr, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 2 U2 3 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD JUN PY 2003 VL 59 IS 6 BP 3 EP 3 PG 1 WC Engineering, Mechanical SC Engineering GA 698ZP UT WOS:000184031000001 ER PT J AU Marchetti, M Jones, WR Sicre, J AF Marchetti, M Jones, WR Sicre, J TI Relative lifetimes of MAPLUB (R) Greases for space applications (c) SO LUBRICATION ENGINEERING LA English DT Article DE aerospace tribology; grease; lubricant degradation; synthetic lubricants ID ROLLING-CONTACT TRIBOMETER; SPIRAL ORBIT TRIBOMETRY; VACUUM; PERFORMANCE AB A Spiral Orbit Tribometer was employed to evaluate the tribological behavior and relative lifetimes of several commercially available greases under ultrahigh vacuum. These greases are either based on a multiply alkylated cyclopentane oil, or a pefluoropolyalkylether oil, and a thickener made of polytetrafluoroethylene (PTFE) telomer. The multiply alkylated cyclopentane (MAC) greases yielded long lifetimes, while perfluoropolyalkylether (PFPE) greases yielded short lifetimes. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Ctr Natl Etud Spatiales, Dept Mecanismes, F-31055 Toulouse, France. RP Marchetti, M (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 23 TC 2 Z9 2 U1 1 U2 4 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD JUN PY 2003 VL 59 IS 6 BP 11 EP 15 PG 5 WC Engineering, Mechanical SC Engineering GA 698ZP UT WOS:000184031000003 ER PT J AU Donohue, MJ AF Donohue, MJ TI How multiagency partnerships can successfully address large-scale pollution problems: a Hawaii case study SO MARINE POLLUTION BULLETIN LA English DT Article DE Hawaii; management; NGOs; partnership ID ISLANDS AB Oceanic circulation patterns deposit significant amounts of marine pollution, including derelict fishing gear from North Pacific Ocean fisheries, in the Hawaiian Archipelago [Mar. Pollut. Bull. 42(12) (2001) 1301]. Management responsibility for these islands and their associated natural resources is shared by several government authorities. Non-governmental organizations (NGOs) and private industry also have interests in the archipelago. Since the marine debris problem in this region is too large for any single agency to manage, a multiagency marine debris working group (group) was established in 1998 to improve marine debris mitigation in Hawaii. To date, 16 federal, state, and local agencies, working with industry and NGOs, have removed 195 tons of derelict fishing gear from the Northwestern Hawaiian Islands. This review details the evolution of the partnership, notes its challenges and rewards, and advocates its continued use as an effective resource management tool. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 SW Fisheries Sci Ctr, Natl Marine Fisheries Serv, Honolulu Lab, Honolulu, HI 96822 USA. RP SW Fisheries Sci Ctr, Natl Marine Fisheries Serv, Honolulu Lab, 2570 Dole St, Honolulu, HI 96822 USA. EM mary.donohue@noaa.gov NR 5 TC 8 Z9 9 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0025-326X EI 1879-3363 J9 MAR POLLUT BULL JI Mar. Pollut. Bull. PD JUN PY 2003 VL 46 IS 6 BP 700 EP 702 DI 10.1016/S0025-326X(02)00256-4 PG 3 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 694AA UT WOS:000183749500014 PM 12787578 ER PT J AU Hazen, RM Sholl, DS AF Hazen, RM Sholl, DS TI Chiral selection on inorganic crystalline surfaces SO NATURE MATERIALS LA English DT Review ID DENSITY-FUNCTIONAL THEORY; RACEMIC AMINO-ACIDS; PLATINUM SURFACES; BIOMOLECULAR HOMOCHIRALITY; ENANTIOSPECIFIC ADSORPTION; HETEROGENEOUS CATALYSIS; METAL-SURFACES; ENANTIOSELECTIVE SYNTHESIS; ASYMMETRIC ADSORPTION; OPTICAL-ACTIVITY AB From synthetic drugs to biodegradable plastics to the origin of life, the chiral selection of molecules presents both daunting challenges and significant opportunities in materials science. Among the most promising, yet little explored, avenues for chiral molecular discrimination is adsorption on chiral crystalline surfaces periodic environments that can select, concentrate and possibly even organize molecules into polymers and other macromolecular structures. Here we review experimental and theoretical approaches to chiral selection on inorganic crystalline surfaces-research that is poised to open this new frontier in understanding and exploiting surface-molecule interactions. C1 Carnegie Inst Washington, Washington, DC 20015 USA. NASA, Astrobiol Inst, Washington, DC 20015 USA. Carnegie Mellon Univ, Dept Chem Engn, Pittsburgh, PA 15213 USA. RP Hazen, RM (reprint author), Carnegie Inst Washington, 5241 Broad Branch Rd NW, Washington, DC 20015 USA. EM r.hazen@gl.ciw.edu NR 101 TC 225 Z9 225 U1 8 U2 95 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 1476-1122 J9 NAT MATER JI Nat. Mater. PD JUN PY 2003 VL 2 IS 6 BP 367 EP 374 DI 10.1038/nmat879 PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 688CR UT WOS:000183415700010 PM 12776102 ER PT J AU Gaskin, JA Sharma, DP Ramsey, BD AF Gaskin, JA Sharma, DP Ramsey, BD TI Charge sharing and charge loss in a cadmium-zinc-telluride fine-pixel detector array SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 10th Symposium on Radiation Measurements and Applications CY MAY 21-23, 2002 CL ANN ARBOR, MICHIGAN DE cadmium-zinc-telluride; hard X-ray detector; HERO AB Because of its high atomic number, room temperature operation, low noise, and high spatial resolution a cadmium-zinc-telluride multi-pixel detector is ideal for hard X-ray astrophysical observation. As part of on-going research at MSFC to develop multi-pixel CdZnTe detectors for this purpose, we have measured charge sharing and charge loss for a 4 x 4 (750 mum pitch), 1 mm thick pixel array and modeled these results using a Monte-Carlo simulation. This model was then used to predict the amount of charge sharing for a much finer pixel array (with a 300 mum pitch). Future work will enable us to compare the simulated results for the finer array to measured values. (C) 2003 Published by Elsevier Science B.V. C1 Univ Alabama, Dept Phys, OB 330, Huntsville, AL 35899 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Gaskin, JA (reprint author), Univ Alabama, Dept Phys, OB 330, Huntsville, AL 35899 USA. NR 4 TC 5 Z9 5 U1 0 U2 6 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 JUN 1 PY 2003 VL 505 IS 1-2 BP 122 EP 125 DI 10.1016/S0168-9002(03)01033-7 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 693JJ UT WOS:000183713700030 ER PT J AU Koch, GJ AF Koch, GJ TI Automatic laser frequency locking to gas absorption lines SO OPTICAL ENGINEERING LA English DT Article DE frequency stabilization; modulation spectroscopy; lidar; differential absorption lidar ID MODULATION SPECTROSCOPY; WATER-VAPOR; STABILIZATION AB An electronic circuit is developed for automating the implementation of a laser frequency-locking technique based on wavelength modulation spectroscopy. The locking scheme uses a zero-crossing as a reference point to line center generated by a derivative-like error signal. Prior implementations have suffered from a limitation in that the zero-crossing must be manually distinguished from the zero signal encountered when the laser is tuned far from line center. This disadvantage is eliminated by developing a circuit that automatically searches the laser's tuning range for an absorption peak and then engages the frequency lock. Both solid state and diode lasers are locked to absorption lines of gases including water vapor and carbon dioxide, with a long-term stabilization to within a few percent of the absorption linewidth. (C) 2003 society of Photo-Optical Instrumentation Engineers. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Koch, GJ (reprint author), NASA, Langley Res Ctr, MS 468, Hampton, VA 23681 USA. NR 11 TC 11 Z9 11 U1 0 U2 5 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 2003 VL 42 IS 6 BP 1690 EP 1693 DI 10.1117/1.1572887 PG 4 WC Optics SC Optics GA 687JQ UT WOS:000183373500022 ER PT J AU Lay, OP Dubovitsky, S Peters, RD Burger, JP Ahn, SW Steier, WH Fetterman, HR Chang, Y AF Lay, OP Dubovitsky, S Peters, RD Burger, JP Ahn, SW Steier, WH Fetterman, HR Chang, Y TI MSTAR: a submicrometer, absolute metrology system SO OPTICS LETTERS LA English DT Article ID INTERFEROMETRY; RESOLUTION AB The Modulation Sideband Technology for Absolute Ranging (MSTAR) sensor permits absolute distance measurement with subnanometer accuracy, an improvement of 4 orders of magnitude over current techniques. The system uses fast phase modulators to resolve the integer cycle ambiguity of standard interferometers. The concept is described and demonstrated over target distances up to 1 in. The design can be extended to kilometer-scale separations. (C) 2003 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ So Calif, Dept Elect Engn, Los Angeles, CA 90089 USA. Pacific Wave Ind, Los Angeles, CA 90025 USA. RP Lay, OP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 50 Z9 50 U1 0 U2 6 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUN 1 PY 2003 VL 28 IS 11 BP 890 EP 892 DI 10.1364/OL.28.000890 PG 3 WC Optics SC Optics GA 679NA UT WOS:000182927700008 PM 12816236 ER PT J AU Siegert, J Gaarder, A Marcinkevicius, S Leon, R Chaparro, S Johnson, SR Sadofyev, Y Zhang, YH AF Siegert, J Gaarder, A Marcinkevicius, S Leon, R Chaparro, S Johnson, SR Sadofyev, Y Zhang, YH TI Photoexcited carrier dynamics in aligned InAs/GaAs quantum dots grown on strain-relaxed InGaAs layers SO PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES LA English DT Article DE quantum dots; dislocations; lateral alignment; time-resolved photoluminescence ID CAPTURE; GAAS; TEMPERATURE; RELAXATION; PHONON; PHOTOLUMINESCENCE; DISLOCATIONS; EPITAXY; WELLS AB Carrier dynamics in aligned InAs/GaAs quantum dots (QDs) grown on cross-batched patterns induced by metastable InxGa1-xAs layers have been studied by time-resolved photoluminescence. The low-temperature carrier lifetimes were found to be of the order of 100-200 ps and determined by carrier trapping and nonradiative recombination. Comparisons with control "nonaligned" InAs QDs show remarkable differences in dependence of peak PL intensities on excitation power, and in PL decay times dependences on both temperature and excitation intensities. Possible origin of traps, which determine the carrier lifetimes, is discussed. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Royal Inst Technol, IMIT Opt, Dept Microelect & Informat Technol, KTH Electrum 229, S-16440 Stockholm, Sweden. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Arizona State Univ, Ctr Solid State Elect Res, Tempe, AZ 85287 USA. Arizona State Univ, Dept Elect Engn, Tempe, AZ 85287 USA. RP Siegert, J (reprint author), Royal Inst Technol, IMIT Opt, Dept Microelect & Informat Technol, KTH Electrum 229, S-16440 Stockholm, Sweden. NR 24 TC 8 Z9 8 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-9477 J9 PHYSICA E JI Physica E PD JUN PY 2003 VL 18 IS 4 BP 541 EP 546 DI 10.1016/S1386-9477(03)00232-7 PG 6 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 695TK UT WOS:000183846300020 ER PT J AU Kulikov, I Zak, M AF Kulikov, I Zak, M TI Shock waves in a Bose-Einstein condensate SO PHYSICAL REVIEW A LA English DT Article ID COLLECTIVE EXCITATIONS; GROUND-STATE; GAS AB A theoretical possibility of shock wave formation in a high-density Bose-Einstein condensate with strong repulsive interaction is reported. A mechanism of transformation of sound waves into shock waves is described. The speed of shock waves as well as relationships between jumps of velocity and density at the front of the surface of discontinuity are derived. The theory is illustrated by the analytical solution for shock wave propagation in a dense condensate cloud. C1 CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, Pasadena, CA 91109 USA. RP Kulikov, I (reprint author), CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 18 TC 15 Z9 15 U1 0 U2 0 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 2003 VL 67 IS 6 AR 063605 DI 10.1103/PhysRevA.67.063605 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 696YM UT WOS:000183915200105 ER PT J AU Safaeinili, A Kofman, W Nouvel, JF Herique, A Jordan, RL AF Safaeinili, A Kofman, W Nouvel, JF Herique, A Jordan, RL TI Impact of Mars ionosphere on orbital radar sounder operation and data processing SO PLANETARY AND SPACE SCIENCE LA English DT Article DE Mars subsurface; radar sounding; Mars ionosphere; Faraday rotation; mars stratigraphy; radio wave propagation through ionosphere ID ATMOSPHERE AB Orbiting radar sounders may become the primary tools in global investigation of Mars subsurface. Orbital radar sounding of Mars is complicated by the presence of a significant ionosphere. The need to penetrate deep requires radar operation at a MHz frequency regime which makes ionospheric distortions unavoidable. This paper addresses the issues that a radar sounder will face when operating close to the ionosphere's plasma frequency. Although the results of this paper are general, the main focus is Mars Advance Radar for Subsurface and Ionospheric Sounding (MARSIS) that will arrive at Mars in early 2004 aboard the European Space Agency's Mars Express Spacecraft. This paper will quantify the impact of the ionosphere on the radar sounding operation and data processing and will provide potential schemes for correcting the ionospheric distortion. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Labs, Pasadena, CA 91109 USA. Univ Grenoble 1, Lab Planetol Grenoble, CNRS, Grenoble, France. RP Safaeinili, A (reprint author), CALTECH, Jet Prop Labs, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Kofman, Wlodek/C-4556-2008; Herique, Alain/E-7210-2017 OI Herique, Alain/0000-0003-3699-883X NR 10 TC 41 Z9 41 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JUN-JUL PY 2003 VL 51 IS 7-8 BP 505 EP 515 DI 10.1016/S0032-0633(03)00048-5 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 694CT UT WOS:000183756800005 ER PT J AU Feinberg, LR Peterson, WT AF Feinberg, LR Peterson, WT TI Variability in duration and intensity of euphausiid spawning off central Oregon, 1996-2001 SO PROGRESS IN OCEANOGRAPHY LA English DT Article; Proceedings Paper CT 10th Annual Meeting of the North-Pacific-Marine-Science-Organization (PICES) CY OCT, 2001 CL VICTORIA, CANADA SP N Pacific Marine Sci Org DE euphausiid spawning; Euphausia pacifica; Thysanoessa spinifera ID WARM OCEAN YEARS; POPULATION BIOLOGY; INTERANNUAL VARIATIONS; BARKLEY SOUND; PACIFICA; PRODUCTIVITY; OSCILLATION; CANADA AB We tracked the duration and intensity of the euphausiid spawning season through biweekly sampling along a transect off Newport, OR (latitude 44degrees40'N) over a six year period from 1996 to 2001. Our sampling consisted of vertical plankton tows, CTD casts, and collection of water for determination of chlorophyll a. Here, we report on data collected from two stations, 5 and 15 nautical miles (9.3 and 27.8 km) offshore. The density of euphausiid eggs in our samples was highly variable spatially and temporally; we saw the most striking differences in egg densities and length of the spawning season, when we compared spawning before and after 1999. This year corresponded to the time when the Pacific Decadal Oscillation switched from warm phase (pre-1999) to cool phase (1999-present). The years 1996 and 1997 were characterized by one large, late summer peak in egg density at our inshore station. 1998, an El Nino year, followed this pattern for our offshore station, but eggs were nearly absent at our inshore station. Starting in 1999, we saw multiple peaks in egg density and found that the spawning season extended from spring through early fall. For example, in spring (March-May) at the inshore station, the abundance of eggs increased from an average of 0.4 m(-3) (1996-1998) to 51.3 m(-3) (1999-2001), and for summer (July-September), 27.8 m(-3) to 132.6 m(-3) for the same time period. At the offshore station, egg abundances doubled over the same two time periods: 7 m(-3) versus 11 m(-3) (spring) and 55 m(-3) versus 186 m(-3) (summer). Peaks in egg densities were often associated with phytoplankton blooms, but not in a predictable way. Peaks in egg densities often followed cold-water upwelling events, especially at the inshore station. It is not yet clear whether this connection is due to changes in advection or changes in upwelling-induced productivity. (C) 2003 Elsevier Ltd. All rights reserved. C1 Oregon State Univ, Hatfield Marine Sci Ctr, Cooperat Inst Marine Resources Studies, Newport, OR 97365 USA. Natl Marine Fisheries Serv, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. RP Feinberg, LR (reprint author), Oregon State Univ, Hatfield Marine Sci Ctr, Cooperat Inst Marine Resources Studies, 2030 S Marine Sci Dr, Newport, OR 97365 USA. NR 29 TC 44 Z9 45 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0079-6611 J9 PROG OCEANOGR JI Prog. Oceanogr. PD JUN PY 2003 VL 57 IS 3-4 BP 363 EP 379 DI 10.1016/S0079-6611(03)00106-X PG 17 WC Oceanography SC Oceanography GA 724VJ UT WOS:000185507100009 ER PT J AU Johnson, C Holloway, CM AF Johnson, C Holloway, CM TI A survey of logic formalisms to support mishap analysis SO RELIABILITY ENGINEERING & SYSTEM SAFETY LA English DT Article DE mishap logics; causation; im plication; accident investigation; mishap investigation ID PETRI NETS; CONDITIONALS AB Mishap investigations provide important information about adverse events and near miss incidents. They are intended to help avoid any recurrence of previous failures. Over time, they can also yield statistical information about incident frequencies that helps to detect patterns of failure and can validate risk assessments. However, the increasing complexity of many safety critical systems is posing new challenges for mishap analysis. Similarly, the recognition that many failures have complex, systemic causes has helped to widen the scope of many mishap investigations. These two factors have combined to pose new challenges for the analysis of adverse events. A new generation of formal and semi-formal techniques have been proposed to help investigators address these problems. We introduce the term 'mishap logics' to collectively describe these notations that might be applied to support the analysis of mishaps. The proponents of these notations have argued that they can be used to formally prove that certain events created the necessary and sufficient causes for a mishap to occur. These proofs can be used to reduce the bias that is often perceived to effect the interpretation of adverse events. Others have argued that one cannot use logic formalisms to prove causes in the same way that one might prove propositions or theorems. Such mechanisms cannot accurately capture the wealth of inductive, deductive and statistical forms of inference that investigators must use in their analysis of adverse events. This paper provides an overview of these mishap logics. It also identifies several additional classes of logic that might also be used to support mishap analysis. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Univ Glasgow, Dept Comp Sci, Glasgow G12 8QQ, Lanark, Scotland. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Johnson, C (reprint author), Univ Glasgow, Dept Comp Sci, Glasgow G12 8QQ, Lanark, Scotland. NR 33 TC 14 Z9 15 U1 1 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0951-8320 J9 RELIAB ENG SYST SAFE JI Reliab. Eng. Syst. Saf. PD JUN PY 2003 VL 80 IS 3 BP 271 EP 291 DI 10.1016/S0951-8320(03)00053-X PG 21 WC Engineering, Industrial; Operations Research & Management Science SC Engineering; Operations Research & Management Science GA 672CX UT WOS:000182504400005 ER PT J AU Sheridan, P Henderson, C McMahan, G AF Sheridan, P Henderson, C McMahan, G TI Fauna of natural seagrass and transplanted Halodule wrightii (shoalgrass) beds in Galveston Bay, Texas SO RESTORATION ECOLOGY LA English DT Article DE seagrass; transplant; nekton; fishes; decapods; benthos; community structure; shoalgrass; Halodule wrightii; habitat restoration ID PRAWNS PENAEUS-ESCULENTUS; INDIAN RIVER LAGOON; FISH ASSEMBLAGES; LEAF DENSITY; MEADOWS; FLORIDA; RESTORATION; AUSTRALIA; CRUSTACEANS; ABUNDANCE AB We compared nekton and benthos densities and community compositions in a natural mixed seagrass bed dominated by Halodule wrightii (shoalgrass) with those found in three shoalgrass transplant sites and adjoining sand habitats in western Galveston Bay, Texas, U.S.A. Quantitative drop traps and cores were used to compare communities up to seven times over 36 months post-transplant where transplant beds survived. Total densities of fishes, decapods, annelids, benthic crustaceans, and most dominant species were significantly higher in natural seagrass than in transplanted shoalgrass or sand habitats during most sampling periods. On occasion, fish and decapod densities were significantly higher in transplanted shoalgrass than in adjoining sand habitats. No consistent faunal differences were found among transplant sites before two of three sites failed. Taxonomic comparison of community compositions indicated that nekton and benthos communities in natural seagrass beds were usually distinct from those in transplanted beds or sand habitats, which were similar. We conclude that reestablishing a shoalgrass bed that resembles a natural seagrass bed and its faunal communities in the Galveston Bay system will take longer than 3 years, provided that transplants persist. C1 Natl Marine Fisheries Serv, NOAA, SE Fisheries Sci Ctr, Fishery Ecol Branch, Galveston, TX 77551 USA. RP Sheridan, P (reprint author), Natl Marine Fisheries Serv, NOAA, SE Fisheries Sci Ctr, 3500 Delwood Beach Rd, Panama City, FL 32408 USA. EM pete.sheridan@noaa.gov NR 52 TC 9 Z9 9 U1 4 U2 15 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1061-2971 EI 1526-100X J9 RESTOR ECOL JI Restor. Ecol. PD JUN PY 2003 VL 11 IS 2 BP 139 EP 154 DI 10.1046/j.1526-100X.2003.00126.x PG 16 WC Ecology SC Environmental Sciences & Ecology GA 682EM UT WOS:000183078400003 ER PT J AU Liu, ZS Wu, D Zhang, KL Liu, JT Hair, JW She, CY AF Liu, ZS Wu, D Zhang, KL Liu, JT Hair, JW She, CY TI A mobile incoherent Mie-Rayleigh Doppler wind lidar with a single frequency and tunable operation of an injection Nd : YAG laser SO SCIENCE IN CHINA SERIES E-TECHNOLOGICAL SCIENCES LA English DT Article DE mobile Doppler wind lidar; iodine-vapor discriminator ID ATMOSPHERIC WIND; EDGE TECHNIQUE; RESOLUTION; FILTER AB A mobile incoherent Doppler lidar system has been experimentally demonstrated to be able to transmit reliable single frequency operation laser pulse, even after truck transit and in very high vibration environments. The linewidth of the injection-seeded pulse Nd:YAG laser can be measured by means of an I-2 molecular filter. And, lidar validation experiments demonstrated the feasibility and capability of measuring wind field by the Mie-Rayleigh Doppler wind lidar. The uncertainty of measured wind speed is 0.985m/s in the altitude range from 2 to 4 km. C1 Ocean Univ China, Minist Educ China, Key Lab Ocean Remote Sensing, Qingdao 266003, Peoples R China. NASA, Langley Res Ctr, Atmospher Sci, Hampton, VA 23681 USA. Colorado State Univ, Dept Phys, Ft Collins, CO 80523 USA. RP Wu, D (reprint author), Ocean Univ China, Minist Educ China, Key Lab Ocean Remote Sensing, Qingdao 266003, Peoples R China. EM dongwu@ouqd.edu.cn NR 14 TC 2 Z9 11 U1 6 U2 10 PU SCIENCE PRESS PI BEIJING PA 16 DONGHUANGCHENGGEN NORTH ST, BEIJING 100717, PEOPLES R CHINA SN 1006-9321 J9 SCI CHINA SER E JI Sci. China Ser. E-Technol. Sci. PD JUN PY 2003 VL 46 IS 3 BP 309 EP 317 DI 10.1360/03ye9034 PG 9 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 698FD UT WOS:000183986500010 ER PT J AU Li, Y Niu, GF Cressler, JD Patel, J Liu, ST Reed, RA Mojarradi, MM Blalock, BJ AF Li, Y Niu, GF Cressler, JD Patel, J Liu, ST Reed, RA Mojarradi, MM Blalock, BJ TI The operation of 0.35 mu m partially depleted SOICMOS technology in extreme environments SO SOLID-STATE ELECTRONICS LA English DT Article DE SOI; partially depleted; CMOS; low temperature electronics; high temperature electronics; radiation; impact ionization ID CMOS TECHNOLOGY AB We evaluate the usefulness of partially depleted Sol CMOS devices fabricated in a 0.35 mu-m, technology on UNI-BOND material for electronics applications requiring robust operation under extreme environment conditions consisting of low and/or high temperature, and under substantial radiation exposure. The threshold voltage, effective mobility, and the impact ionization parameters were determined across temperature for both the nFETs and the pFETs. The radiation response was characterized using threshold voltage shifts of both the front-gate and back-gate transistors. These results suggest that this 0.35 pm partially depleted Sol CMOS technology is suitable for operation across a wide range of extreme environment conditions consisting of. cryogenic temperatures down to 86 K, elevated temperatures up to 573 K, and under radiation exposure to 1.3 Mrad(Si) total dose. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Auburn Univ, Alabama Microelect Sci & Technol Ctr, Dept Elect & Comp Engn, Auburn, AL 36849 USA. Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Honeywell Solid State Elect Ctr, Plymouth, MN 55441 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Tennessee, Dept Elect & Comp Engn, Knoxville, TN 37996 USA. RP Li, Y (reprint author), Auburn Univ, Alabama Microelect Sci & Technol Ctr, Dept Elect & Comp Engn, 200 Broun Hall, Auburn, AL 36849 USA. NR 10 TC 9 Z9 9 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-1101 J9 SOLID STATE ELECTRON JI Solid-State Electron. PD JUN PY 2003 VL 47 IS 6 BP 1111 EP 1115 DI 10.1016/S0038-1101(02)00516-6 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 668EM UT WOS:000182277400027 ER PT J AU Turner, W Spector, S Gardiner, N Fladeland, M Sterling, E Steininger, M AF Turner, W Spector, S Gardiner, N Fladeland, M Sterling, E Steininger, M TI Remote sensing for biodiversity science and conservation SO TRENDS IN ECOLOGY & EVOLUTION LA English DT Review ID FOREST; LIDAR; FRAGMENTATION; DEFORESTATION; EXTINCTION; DIVERSITY; ECOSYSTEM; RICHNESS; PATTERNS; COVER AB Remote-sensing systems typically produce imagery that averages information over tens or even hundreds of square meters-far too coarse to detect most organisms-so the remote sensing of biodiversity would appear to be a fool's errand. However, advances in the spatial and spectral resolutions of sensors now available to ecologists are making the direct remote sensing of certain aspects of biodiversity increasingly feasible; for example, distinguishing species assemblages or even identifying species of individual trees. In cases where direct detection of individual organisms or assemblages is still beyond our grasp, indirect approaches offer valuable information about diversity patterns. Such approaches derive meaningful environmental parameters from biophysical characteristics that are revealed by remote sensing. C1 NASA, Off Earth Sci, Washington, DC 20546 USA. Amer Museum Nat Hist, Ctr Biodivers & Conservat, New York, NY 10024 USA. NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. Conservat Int, Ctr Appl Biodivers Sci, Washington, DC 20036 USA. RP Turner, W (reprint author), NASA, Off Earth Sci, Mail Code YS, Washington, DC 20546 USA. RI Beckley, Matthew/D-4547-2013 NR 38 TC 510 Z9 539 U1 28 U2 231 PU ELSEVIER SCIENCE LONDON PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0169-5347 J9 TRENDS ECOL EVOL JI Trends Ecol. Evol. PD JUN PY 2003 VL 18 IS 6 BP 306 EP 314 DI 10.1016/S0169-5347(03)00070-3 PG 9 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA 689WM UT WOS:000183516000013 ER PT J AU Kajander, EO Ciftcioglu, N Aho, K Garcia-Cuerpo, E AF Kajander, EO Ciftcioglu, N Aho, K Garcia-Cuerpo, E TI Characteristics of nanobacteria and their possible role in stone formation SO UROLOGICAL RESEARCH LA English DT Editorial Material DE nanobacteria; calcification; kidney stones; nephrolithiasis; nephrocalcinosis ID POLYCYSTIC KIDNEY-DISEASE; INHIBIT BONE-RESORPTION; CALCIUM UROLITHIASIS; RENAL-CALCULI; NEPHROLITHIASIS; CALCIFICATION; PROTEIN; LIGHT; MINERALIZATION; GROWTH AB Kidney stone formation is a multifactorial disease in which the defence mechanisms and risk factors are imbalanced in favour of stone formation. We have proposed a novel infectious agent, mineral forming nanobacteria (NB), to be active nidi that attach to, invade and damage the urinary epithelium of collecting ducts and papilla forming the calcium phosphate center(s) found in most kidney stones. Stone formation may proceed in urine supersaturated with calcium phosphate, calcium oxalate and uric acid/urate under the influence of crystallization promoters and inhibitors. Our hypothesis underlines the role of active nidi: even supersaturated urine requires nidi for crystallization to appear. C1 Univ Kuopio, Dept Biochem, FIN-70211 Kuopio, Finland. Nanobac Oy, Kuopio, Finland. NASA, Lyndon B Johnson Space Ctr, USRA, Houston, TX 77058 USA. Univ Alcala de Henares, Hosp Ramon y Cajal, Madrid, Spain. RP Kajander, EO (reprint author), Univ Kuopio, Dept Biochem, POB 1627, FIN-70211 Kuopio, Finland. EM olavi.kajander@uku.fi NR 52 TC 49 Z9 61 U1 1 U2 4 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0300-5623 J9 UROL RES JI Urol. Res. PD JUN PY 2003 VL 31 IS 2 BP 47 EP 54 DI 10.1007/s002440-003-0304-7 PG 8 WC Urology & Nephrology SC Urology & Nephrology GA 696NA UT WOS:000183891900001 PM 12669155 ER PT J AU Sheridan, P Hays, C AF Sheridan, P Hays, C TI Are mangroves nursery habitat for transient fishes and decapods? SO WETLANDS LA English DT Article DE mangroves nursery; fishes; decapods; habitat; estuary; coastal zone; conservation; meta-analysis ID TROPICAL AUSTRALIAN ESTUARY; JUVENILE BANANA PRAWNS; STABLE-ISOTOPE; SPECIES COMPOSITION; COMMUNITY STRUCTURE; PENAEID PRAWNS; NEARSHORE HABITATS; TEMPORAL PATTERNS; INSHORE WATERS; ROOKERY BAY AB The term nursery implies a special place for juvenile nekton (fishes and decapod crustaceans) where density, survival, and growth of juveniles and movement to adult habitat are enhanced over those in adjoining juvenile habitat types. We reviewed recent literature concerning these four topics and conducted meta-analyses for density and survival data. Most studies of mangroves as nurseries have addressed only occurrence or density of fishes or decapods, have not used quantitative sampling methods, and have not compared alternate habitats. Comparison of nekton densities among alternate habitats suggests that, at times, lower densities may be typical of mangroves when compared to seagrass, coral reef, marsh, and non-vegetated habitats. There is little direct consumption of mangrove detritus by nekton. C, N, and S isotope studies reveal little retention of mangrove production by higher consumers. Densities of prey for transient fishes and decapods may be greater within mangroves than elsewhere, but there has been no verification that food availability affects growth or survival. Experimental evidence indicates that mangrove roots and debris provide refuge for small nekton from predators, thus enhancing overall survival. There is no evidence that more individuals move to adult habitats from mangroves than from alternate inshore habitats. There is an obvious need to devise appropriate experiments to test the nursery functions of mangroves. Such data may then be one more reason to add support for mangrove conservation and preservation. C1 NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Galveston, TX 77551 USA. Univ Calif Santa Cruz, Dept Biol, Santa Cruz, CA 95064 USA. RP Sheridan, P (reprint author), NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, 3500 Delwood Beach Rd, Panama City, FL 32408 USA. EM pete.sheridan@noaa.gov NR 97 TC 91 Z9 98 U1 5 U2 37 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0277-5212 EI 1943-6246 J9 WETLANDS JI Wetlands PD JUN PY 2003 VL 23 IS 2 BP 449 EP 458 DI 10.1672/19-20 PG 10 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA 698UB UT WOS:000184016200019 ER PT J AU Burlaga, LF Wang, C Ness, NF AF Burlaga, LF Wang, C Ness, NF TI A model and observations of the multifractal spectrum of the heliospheric magnetic field strength fluctuations near 40 AU SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID COSMIC-RAY MODULATION; VOYAGER-2 OBSERVATIONS; SOLAR-WIND; TURBULENCE; FRACTALS AB The Voyager 1 (V1) observations of the magnetic field strength as a function of time during 1989, between 36.3 and 38.8 AU, have a multifractal structure in the range of scales from 2 to 32 days. We show that a 1-D multi-fluid MHD model with observations made at 1 AU during 1999 as input predicts the multifractal structure at 40 AU. The multifractal spectrum determined from the time series at 40 AU predicted by the model agrees with that observed by V1. The observed multifractal scaling symmetry can be explained by a deterministic model. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Chinese Acad Sci, Lab Space Weather, Beijing, Peoples R China. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. RP NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 692, Greenbelt, MD 20771 USA. EM Leonard.F.Burlaga@nasa.gov; cw@space.mit.edu; nfness@udel.edu NR 27 TC 19 Z9 19 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 MAY 31 PY 2003 VL 30 IS 10 AR 1543 DI 10.1029/2003GL016903 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 686CG UT WOS:000183302500004 ER PT J AU Zheng, YH Lynch, KA Boehm, M Goldstein, R Javadi, H Schuck, P Arnoldy, RL Kintner, PM AF Zheng, YH Lynch, KA Boehm, M Goldstein, R Javadi, H Schuck, P Arnoldy, RL Kintner, PM TI Multipoint measurements of field-aligned current density in the auroral zone SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE free-flying magnetometers; multipoint magnetic field measurements; spatial or temporal features; correlative wavelet analysis; magnetic field data reduction ID KINETIC ALFVEN WAVES; ELECTRIC-FIELDS; PLASMA SHEET; SPACECRAFT; ARC; REGION; POLAR AB [1] In this paper we present the analysis and interpretation of a multipoint observation of magnetic field structures at the poleward edge of a premidnight auroral arc by the Enstrophy sounding rocket mission. Four Free-Flying Magnetometers (FFMs) employing autonomous nanospacecraft technology were deployed from the main payload during the flight, and multipoint magnetic field measurements were made. Signatures consistent with both spatial and temporal interpretations were found to be present when large fluctuations in B were seen at the edge of an arc as the rocket flew into the polar cap. Reasons for the interpretation of spatial or temporal features are given and supported by a simple model of multiple payloads crossing through several moving current sheets and a study of the fine structure of this auroral event using multipoint, correlative wavelet analysis to find velocities of structures at different scale sizes. We show that the direct measurement method of current density using multipoint measurement of magnetic fields gives us a different current density than what would be inferred from a single-point measurement and that the multipoint measurement also provides an inherent check on the validity of the measurement through a calculation of the divergence of the measured B. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. Dartmouth Coll, Dept Phys & Astron, Wilder Lab, Hanover, NH 03755 USA. Lockheed Martin Adv Technol Ctr, Palo Alto, CA 94304 USA. SW Res Inst, San Antonio, TX 78238 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. USN, Res Lab, Washington, DC 20375 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Cornell Univ, Sch Elect & Comp Engn, Ithaca, NY 14853 USA. RP Zheng, YH (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. RI Zheng, Yihua/D-7368-2012 NR 29 TC 7 Z9 7 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 30 PY 2003 VL 108 IS A5 AR 1217 DI 10.1029/2002JA009450 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 686CZ UT WOS:000183304100001 ER PT J AU Wang, YJ Buermann, W Stenberg, P Smolander, H Hame, T Tian, YH Hu, JN Knyazikhin, Y Myneni, RB AF Wang, YJ Buermann, W Stenberg, P Smolander, H Hame, T Tian, YH Hu, JN Knyazikhin, Y Myneni, RB TI A new parameterization of canopy spectral response to incident solar radiation: case study with hyperspectral data from pine dominant forest SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE vegetation canopy; parameterization; spectra ID LEAF-AREA INDEX; PHOTOSYNTHETICALLY ACTIVE RADIATION; MULTIANGLE SATELLITE DATA; VEGETATION CANOPIES; INFORMATION-CONTENT; ATMOSPHERE; CLIMATE; TRANSMISSION; REFLECTION; ALGORITHM AB A small set of independent variables generally seems to suffice when attempting to describe the spectral response of a vegetation canopy to incident solar radiation. This set includes the soil reflectance, the single-scattering albedo, canopy transmittance, reflectance and interception, the portion of uncollided radiation in the total incident radiation, and portions of collided canopy transmittance and interception. All of these are measurable; they satisfy a simple system of equations and constitute a set that fully describes the law of energy conservation in vegetation canopies at any wavelength in the visible and near-infrared part of the solar spectrum. Further, the system of equations specifies the relationship between the optical properties at the leaf and the canopy scales. Thus, the information content of hyperspectral data can be fully exploited if these variables can be retrieved, for they can be more directly related to some of the physical properties of the canopy (e.g. leaf area index). This paper demonstrates this concept through retrievals of single-scattering albedo, canopy absorptance, portions of uncollided and collided canopy transmittance, and interception from hyperspectral data collected during a field campaign in Ruokolahti, Finland, June 14-21, 2000. The retrieved variables are then used to estimate canopy leaf area index, vegetation ground cover, and also the ratio of direct to total incident solar radiation at blue, green, red, and near-infrared spectral intervals. (C) 2003 Elsevier Science 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. VTT Automat, Remote Sensing Grp, FIN-02044 Espoo, Finland. RP Wang, YJ (reprint author), Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Rm 3-002,1450 S Rolling Rd, Baltimore, MD 21227 USA. EM yujie@umbc.edu RI Myneni, Ranga/F-5129-2012 NR 33 TC 33 Z9 33 U1 1 U2 9 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAY 30 PY 2003 VL 85 IS 3 BP 304 EP 315 DI 10.1016/S0034-4257(03)00009-9 PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 675UV UT WOS:000182715300005 ER PT J AU de Colstoun, ECB Story, MH Thompson, C Commisso, K Smith, TG Irons, JR AF de Colstoun, ECB Story, MH Thompson, C Commisso, K Smith, TG Irons, JR TI National Park vegetation mapping using multitemporal Landsat 7 data and a decision tree classifier SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE National Park; Landsat 7; decision trees ID REMOTELY-SENSED DATA; COVER CLASSIFICATION; SPATIAL-RESOLUTION; IMAGERY; ALGORITHMS; ACCURACY AB Decision tree classifiers have received much recent attention, particularly with regards to land cover classifications at continental to global scales. Despite their many benefits and general flexibility, the use of decision trees with high spatial resolution data has not yet been fully explored. In support of the National Park Service (NPS) Vegetation Mapping Program (VMP), we have examined the feasibility of using a commercially available decision tree classifier with multitemporal satellite data from the Enhanced Thematic Mapper-Plus (ETM+) instrument to map 11 land cover types at the Delaware Water Gap National Recreation Area near Milford, PA. Ensemble techniques such as boosting and consensus filtering of the training data were used to improve both the quality of the input training data as well as the final products. Using land cover classes as specified by the National Vegetation Classification Standard at the Formation level, the final land cover map has an overall accuracy of 82% (kappa = 0. 80) when tested against a validation data set acquired on the ground (n = 195). This same accuracy is 99.5% when considering only forest vs. nonforest classes. Usage of ETM+ scenes acquired at multiple dates improves the accuracy over the use of a single date, particularly for the different forest types. These results demonstrate the potential applicability and usability of such an approach to the entire National Park system, and to high spatial resolution land cover and forest mapping applications in general. (C) 2003 Elsevier Science Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. Natl Pk Serv, Nat Resource Informat Div, Denver, CO USA. Natl Pk Serv, Delaware Water Gap Natl Recreat Area, Milford, PA USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP de Colstoun, ECB (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Code 923, Greenbelt, MD 20771 USA. RI Irons, James/D-8535-2012 NR 27 TC 77 Z9 77 U1 1 U2 23 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 2003 VL 85 IS 3 BP 316 EP 327 DI 10.1016/S0034-4257(03)00010-5 PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 675UV UT WOS:000182715300006 ER PT J AU Stanescu, D Hussaini, MY Farassat, F AF Stanescu, D Hussaini, MY Farassat, F TI Aircraft engine noise scattering by fuselage and wings: a computational approach SO JOURNAL OF SOUND AND VIBRATION LA English DT Article ID DISCONTINUOUS GALERKIN METHOD; DUCTED FANS; RADIATION; SCHEMES AB The paper presents a time-domain method for computation of sound radiation from aircraft engine sources to the far field. The effects of non-uniform flow around the aircraft and scattering of sound by fuselage and wings are accounted for in the formulation. The approach is based on the discretization of the inviscid flow equations through a collocation form of the discontinuous Galerkin spectral element method. An isoparametric representation of the underlying geometry is used in order to take full advantage of the spectral accuracy of the method. Large-scale computations are made possible by a parallel implementation based on message passing. Results obtained for radiation from an axisymmetric nacelle alone are compared with those obtained when the same nacelle is installed in a generic configuration, with and without a wing. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Florida State Univ, Sch Computat Sci & Informat Technol, Tallahassee, FL 32306 USA. NASA, Langley Res Ctr, Hampton, VA 23669 USA. RP Stanescu, D (reprint author), Florida State Univ, Sch Computat Sci & Informat Technol, 400 DSL Bldg, Tallahassee, FL 32306 USA. NR 19 TC 11 Z9 11 U1 0 U2 4 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 29 PY 2003 VL 263 IS 2 BP 319 EP 333 AR PII S0022-460X(02)01126-4 DI 10.1016/S0022-460X(02)01126-4 PG 15 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 684FT UT WOS:000183195300005 ER PT J AU Bhatia, AK Drachman, RJ AF Bhatia, AK Drachman, RJ TI The mass polarization effect in He-like ions: first and second order SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID BOUND-STATE AB In a paper with a similar title, Yamanaka has calculated the mass polarization effect (to first order in mu/M) for several low-lying states of the two electron atoms and ions with atomic number Z from 2 to 10. Here we improve the previous results by using Hylleraas variational wavefunctions with up to 560 terms and extend the calculation to include some additional states and the Z = 1 ground state. In addition, we compute the second-order effect using the method of pseudostate summation. A nonperturbative method of computation is also discussed and used as a check. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 11 TC 5 Z9 5 U1 0 U2 1 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 28 PY 2003 VL 36 IS 10 BP 1957 EP 1962 AR PII S0953-4075(03)56982-6 DI 10.1088/0953-4075/36/10/306 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 693LV UT WOS:000183719800009 ER PT J AU Sato, M Hansen, J Koch, D Lacis, A Ruedy, R Dubovik, O Holben, B Chin, M Novakov, T AF Sato, M Hansen, J Koch, D Lacis, A Ruedy, R Dubovik, O Holben, B Chin, M Novakov, T TI Global atmospheric black carbon inferred from AERONET SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE aerosols; air pollution; climate change ID SINGLE-SCATTERING ALBEDO; OPTICAL-PROPERTIES; SULFATE AEROSOLS; LIGHT-ABSORPTION; VARIABILITY; SATELLITE; MODEL; DUST; SUN AB AERONET, a network of well calibrated sunphotometers, provides data on aerosol optical depth and absorption optical depth at >250 sites around the world. The spectral range of AERONET allows discrimination between constituents that absorb most strongly in the UV region, such as soil dust and organic carbon, and the more ubiquitously absorbing black carbon (BC). AERONET locations, primarily continental, are not representative of the global mean, but they can be used to calibrate global aerosol climatologies produced by tracer transport models. We find that the amount of BC in current climatologies must be increased by a factor of 2-4 to yield best agreement with AERONET, in the approximation in which BC is externally mixed with other aerosols. The inferred climate forcing by BC, regardless of whether it is internally or externally mixed, is approximate to1 W/m(2), most of which is probably anthropogenic. This positive forcing (warming) by BC must substantially counterbalance cooling by anthropogenic reflective aerosols. Thus, especially if reflective aerosols such as sulfates are reduced, it is important to reduce BC to minimize global warming. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Earth Inst, New York, NY 10025 USA. SGT Inc, New York, NY 10025 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Hansen, J (reprint author), NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RI Dubovik, Oleg/A-8235-2009; Lacis, Andrew/D-4658-2012; Chin, Mian/J-8354-2012 OI Dubovik, Oleg/0000-0003-3482-6460; NR 29 TC 136 Z9 144 U1 3 U2 23 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 27 PY 2003 VL 100 IS 11 BP 6319 EP 6324 DI 10.1073/pnas.0731897100 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 684DT UT WOS:000183190700008 PM 12746494 ER PT J AU Zhao, JJ Lu, JP Han, J Yang, CK AF Zhao, JJ Lu, JP Han, J Yang, CK TI Noncovalent functionalization of carbon nanotubes by aromatic organic molecules SO APPLIED PHYSICS LETTERS LA English DT Article ID GAS CORRELATION-ENERGY; ELECTRONIC-PROPERTIES; ADSORPTION; OXYGEN; IMMOBILIZATION; PHYSISORPTION; GRAPHITE; BUNDLES AB The interaction between carbon nanotubes and organic molecules including benzene (C6H6), cyclohexane (C6H12), and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ:C8N2O2Cl2) have been studied using first principles calculations. The equilibrium tube-molecule distance, adsorption energy, and charge transfer are obtained. The hybridization between the DDQ molecular level and nanotube valence bands transforms the semiconducting tube into a metallic one. Coupling of pi electrons between tubes and aromatic molecules are observed. Our results show that noncovalent functionalization of carbon nanotubes by aromatic molecules is an efficient way to control the electronic properties of carbon nanotubes. (C) 2003 American Institute of Physics. C1 Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. NASA, Ames Res Ctr, Eloret Corp, Moffett Field, CA 95051 USA. Chang Gung Univ, Ctr Gen Educ, Kueishan 333, Taiwan. RP Lu, JP (reprint author), Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. RI Zhao, Jijun/I-6030-2015 NR 23 TC 191 Z9 195 U1 2 U2 39 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 26 PY 2003 VL 82 IS 21 BP 3746 EP 3748 DI 10.1063/1.1577381 PG 3 WC Physics, Applied SC Physics GA 680TB UT WOS:000182993700054 ER PT J AU He, MQ Fahmi, MME Mohammad, SN Jacobs, RN Salamanca-Riba, L Felt, F Jah, M Sharma, A Lakins, D AF He, MQ Fahmi, MME Mohammad, SN Jacobs, RN Salamanca-Riba, L Felt, F Jah, M Sharma, A Lakins, D TI InAs nanowires and whiskers grown by reaction of indium with GaAs SO APPLIED PHYSICS LETTERS LA English DT Article ID GAN NANOWIRES; WIRES; DOTS; NH3 AB Free-standing InAs nanowires and whiskers were grown employing reaction of indium (In) liquid and vapor with GaAs substrate. The arsenic (As) atoms resulting from this reaction were transported by a flow of N-2 or NH3 to the growth location where they reacted with In to produce InAs nanowires and whiskers. Scanning electron microscopy, energy dispersive x-ray spectroscopy, and transmission electron microscopy of the products indicate that the diameter of the nanowires and whiskers ranges from 15 nm to 2 mum depending on the growth temperature, the composition is InAs, and the structure is zinc-blende crystal with [110] or [100] growth direction. The As source and growth mechanism were discussed. The method for synthesis involved no any template, catalyst, toxic As source, nor even lattice matched substrate. (C) 2003 American Institute of Physics. C1 Howard Univ, Mat Sci Res Ctr Excellence, Washington, DC 20059 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Component Technol & Radiat Effects Branch, Greenbelt, MD 20771 USA. RP Mohammad, SN (reprint author), Howard Univ, Mat Sci Res Ctr Excellence, Washington, DC 20059 USA. RI Salamanca-Riba, Lourdes/B-3785-2009 OI Salamanca-Riba, Lourdes/0000-0001-8155-6403 NR 15 TC 39 Z9 39 U1 0 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 26 PY 2003 VL 82 IS 21 BP 3749 EP 3751 DI 10.1063/1.1578519 PG 3 WC Physics, Applied SC Physics GA 680TB UT WOS:000182993700055 ER PT J AU Singh, RP Dey, S Holben, B AF Singh, RP Dey, S Holben, B TI Aerosol behaviour in Kanpur during Diwali festival SO CURRENT SCIENCE LA English DT Article C1 Indian Inst Technol, Dept Civil Engn, Kanpur 208016, Uttar Pradesh, India. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Singh, RP (reprint author), Indian Inst Technol, Dept Civil Engn, Kanpur 208016, Uttar Pradesh, India. NR 4 TC 9 Z9 9 U1 0 U2 4 PU CURRENT SCIENCE ASSN PI BANGALORE PA C V RAMAN AVENUE, PO BOX 8005, BANGALORE 560 080, INDIA SN 0011-3891 J9 CURR SCI INDIA JI Curr. Sci. PD MAY 25 PY 2003 VL 84 IS 10 BP 1302 EP 1304 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 689TT UT WOS:000183509600015 ER PT J AU Wu, XS Choudhari, M AF Wu, XS Choudhari, M TI Linear and nonlinear instabilities of a Blasius boundary layer perturbed by streamwise vortices. Part 2. Intermittent instability induced by long-wavelength Klebanoff modes SO JOURNAL OF FLUID MECHANICS LA English DT Article ID WIND-TUNNEL SCREENS; OBLIQUE WAVES; UPSTREAM FLOW; SHEAR LAYERS; TS-WAVES; TURBULENCE; DISTURBANCES; TRANSITION; EVOLUTION; STABILITY AB This paper presents theoretical results on the instability of a Blasius boundary layer perturbed by Klebanoff modes (i.e. the low-frequency streaks known to be induced by free-stream turbulence). Herein, the Klebanoff distortions are modelled as the signature of a three-dimensional convected gust that may be either isolated or periodic along the spanwise direction. Relatively weak Klebanoff fluctuations can produce O(1) changes to the near-wall curvature of the base flow profile and, hence, fundamentally alter the nature of its instability characteristics. The perturbed flow is shown to support instabilities that are predominantly inviscid and have significantly larger growth rates and characteristic frequencies than the Tollmien-Schlichting (T-S) modes of an unperturbed Blasius flow. The spanwise mode shape of instabilities in the perturbed flow is determined by the Schrodinger equation, with a potential function that corresponds to the skin friction perturbation due to the Klebanoff distortion. The growth rates of these modes are determined by the near-wall torsion of the perturbed flow. The unsteadiness of the Klebanoff distortion is shown to be a crucial element in determining the overall instability characteristics. A localized Klebanoff distortion supports both sinuous and varicose modes of instability, but the sinuous modes are generally more unstable than the varicose modes. Overall, the instability is intermittent in time and localized in space, being confined to certain parts of the modulation cycle and within a specific window(s) along the streamwise direction. In particular, the dominant sinuous modes appear only during the phase in which a low-speed streak dominates the Klebanoff distortion. A periodic distortion supports spatially quasi-periodic modes through a parametric resonance mechanism. The theoretically predicted instability modes share some key features with the unstable disturbances measured in recent experiments, such as the relatively high frequencies, growth rates that depend on the level of free-stream turbulence, small rate of spreading in the lateral direction and, above all, their intermittency in space and time. Non-equilibrium critical-layer theory is used to track a localized sinuous mode through two distinct stages of nonlinear evolution, which eventually terminates in a singularity that indicates the onset of fully nonlinear yet primarily inviscid disturbance dynamics. C1 Stanford Univ, Ctr Turbulence Res, Stanford, CA 94305 USA. Univ London Imperial Coll Sci Technol & Med, Dept Math, London SW7 2BZ, England. NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Hampton, VA 23681 USA. RP Wu, XS (reprint author), Stanford Univ, Ctr Turbulence Res, Stanford, CA 94305 USA. RI Choudhari, Meelan/F-6080-2017 OI Choudhari, Meelan/0000-0001-9120-7362 NR 44 TC 29 Z9 29 U1 0 U2 4 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH ST, NEW YORK, NY 10011-4221 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD MAY 25 PY 2003 VL 483 BP 249 EP 286 DI 10.1017/S0022112003004221 PG 38 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 696AW UT WOS:000183863400010 ER PT J AU Steiner, MB Eshet, Y Rampino, MR Schwindt, DM AF Steiner, MB Eshet, Y Rampino, MR Schwindt, DM TI Fungal abundance spike and the Permian-Triassic boundary in the Karoo Supergroup (South Africa) SO PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY LA English DT Article DE Permian-Triassic boundary; extinction; fungal spike; vertebrates; South Africa ID MASS EXTINCTION; CRISIS; BASIN; EVENT; STRATIGRAPHY; ENVIRONMENTS; MORPHOLOGY; COLLAPSE; PATTERN; CARBON AB The most severe mass extinction of marine species and terrestrial vertebrates and plants is associated with the Permian-Triassic boundary (similar to251 Ma). The extinction interval is also marked by the disappearance of most Late Permian gymnosperm palynomorphs at a layer containing solely the abundant remains of fungi. This 'fungal spike' apparently represents widespread devastation of arboreous vegetation. Stratigraphic and palynological study of the Carlton Heights section in the southern Karoo Basin of South Africa revealed a 1-m-thick fungal spike zone that occurs simultaneously with the last appearance of typically Late Permian gymnosperm pollen. The plant extinction and fungal spike zone are found above the last occurrence of Late Permian mammal-like reptiles of the Dicynodont Zone at other Karoo sections. Using the fungal event as a time line in marine and non-marine sections allows placement of the marine extinctions and the extinction of terrestrial plants and reptiles within a brief crisis interval of less than about 40 000 years at the end of the Permian. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NYU, Earth & Environm Sci Program, New York, NY 10003 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Wyoming, Dept Geol & Geophys, Laramie, WY 82071 USA. Geol Survey Israel, IL-95501 Jerusalem, Israel. Tel Hai Acad Coll, IL-12210 Tel Hai, Israel. RP Rampino, MR (reprint author), NYU, Earth & Environm Sci Program, New York, NY 10003 USA. NR 38 TC 58 Z9 64 U1 1 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-0182 J9 PALAEOGEOGR PALAEOCL JI Paleogeogr. Paleoclimatol. Paleoecol. PD MAY 25 PY 2003 VL 194 IS 4 BP 405 EP 414 DI 10.1016/S0031-0182(03)00230-X PG 10 WC Geography, Physical; Geosciences, Multidisciplinary; Paleontology SC Physical Geography; Geology; Paleontology GA 682HH UT WOS:000183085300004 ER PT J AU Cane, HV von Rosenvinge, TT Cohen, CMS Mewaldt, RA AF Cane, HV von Rosenvinge, TT Cohen, CMS Mewaldt, RA TI Two components in major solar particle events SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID INTERPLANETARY SHOCKS; ENERGETIC PARTICLES; ABUNDANCES; NUCLEON AB [1] A study has been made of 29 intense, solar particle events observed in the energy range 25-80 MeV/nuc near Earth in the years 1997 through 2001. It is found that the majority of the events (19/29) had Fe/O ratios that were reasonably constant with time and energy, and with values above coronal. These all originated on the Sun's western hemisphere and most had intensities that rose rapidly at the time of an associated flare (and coronal mass ejection). Interplanetary shocks observed near Earth had little effect on particle intensities during these events. The remaining 10 events had different intensity-time profiles and Fe/O ratios that varied with time and energy with event-averaged values at or below coronal. Most of these originated near central meridian and 6 had strong interplanetary shocks that were observed near Earth. There were four events with two peaks in the intensity-time profiles, the first near the time of the associated flare (with high Fe/O) and the other at shock passage (with a lower Fe/O) suggesting that solar particle events have two components. At high rigidities the first component (probably flare generated) usually dominates and interplanetary shock-accelerated particles (forming the second component) make a minor contribution except in the case of unusually fast shocks. C1 NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. RP Cane, HV (reprint author), NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM hilary.cane@utas.edu.au; tycho@milkyway.gsfc.nasa.gov; cohen@srl.calthech.edu; rmewaldt@srl.caltech.edu NR 17 TC 94 Z9 94 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 24 PY 2003 VL 30 IS 12 AR 8017 DI 10.1029/2002GL016580 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 683YE UT WOS:000183178000004 ER PT J AU Gopalswamy, N Yashiro, S Lara, A Kaiser, ML Thompson, BJ Gallagher, PT Howard, RA AF Gopalswamy, N Yashiro, S Lara, A Kaiser, ML Thompson, BJ Gallagher, PT Howard, RA TI Large solar energetic particle events of cycle 23: A global view SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CORONAL MASS EJECTIONS; RADIO AB [1] We report on a study of all the large solar energetic particle (SEP) events that occurred during the minimum to maximum interval of solar cycle 23. The main results are: 1. The occurrence rate of the SEP events, long-wavelength type II bursts and the fast and wide frontside western hemispheric CMEs is quite similar, consistent with the scenario that CME-driven shocks accelerate both protons and electrons; major flares have a much higher rate. 2. The SEP intensity is better correlated with the CME speed than with the X-ray flare class. 3. CMEs associated with high-intensity SEPs are about 4 times more likely to be preceded by wide CMEs from the same solar source region, suggesting the importance of the preconditioning of the eruption region. We use a specific event to demonstrate that preceding eruption from a nearby source can significantly affect the properties of SEPs and type II radio bursts. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Catholic Univ Amer, Dept Phys, Inst Astrophys & Computat Sci, Washington, DC 20064 USA. Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico. L3 Com Anal Corp, Greenbelt, MD USA. USN, Res Lab, Solar Phys Branch, Div Space Sci, Washington, DC 20375 USA. RP Gopalswamy, N (reprint author), NASA, Goddard Space Flight Ctr, Code 695, Greenbelt, MD 20771 USA. RI Gopalswamy, Nat/D-3659-2012; Thompson, Barbara/C-9429-2012; Gallagher, Peter/C-7717-2011 OI Gallagher, Peter/0000-0001-9745-0400 NR 9 TC 54 Z9 54 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 24 PY 2003 VL 30 IS 12 AR 8015 DI 10.1029/2002GL016435 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 683YE UT WOS:000183178000002 ER PT J AU Lara, A Gopalswamy, N Nunes, S Munoz, G Yashiro, S AF Lara, A Gopalswamy, N Nunes, S Munoz, G Yashiro, S TI A statistical study of CMEs associated with metric type II bursts SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CORONAL MASS EJECTIONS; WIND SPACECRAFT DATA; RADIO-BURSTS; INTERPLANETARY SHOCKS; SOLAR ERUPTIONS; ORIGIN; SIGNATURES; WAVE AB [1] We present a statistical study of the characteristics of CMEs which show temporal association with type II bursts in the metric domain but not in the decameter/hectometric (DH) domain. This study is based on a set of 80 metric (m) type II bursts associated with surface events in the solar western hemisphere. It was found that in general, the distribution of the widths and speeds of the CMEs associated with metric (but not DH) type II bursts are shifted towards higher values compared to those of all CMEs observed by LASCO in the 1996-2001 period. We also found that these distributions have lower values than the same distributions of the CMEs associated with DH type II bursts. In terms of energy, this means that the CMEs associated only with metric type II bursts are more energetic (wider and faster) than regular CMEs but less energetic than the CMEs associated with DH type II bursts. C1 Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Catholic Univ Amer, Washington, DC 20064 USA. RP Lara, A (reprint author), Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico. RI Gopalswamy, Nat/D-3659-2012 NR 21 TC 25 Z9 25 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 24 PY 2003 VL 30 IS 12 AR 8016 DI 10.1029/2002GL016481 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 683YE UT WOS:000183178000003 ER PT J AU MacDowall, RJ Lara, A Manoharan, PK Nitta, NV Rosas, AM Bougeret, JL AF MacDowall, RJ Lara, A Manoharan, PK Nitta, NV Rosas, AM Bougeret, JL TI Long-duration hectometric type III radio bursts and their association with solar energetic particle (SEP) events SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ACCELERATION; ELECTRONS; MHZ AB [1] It has recently been suggested by Cane et al. [2002] that a class of type III solar radio bursts, called type III-l, is reliably associated with intense solar energetic particle (SEP) events. They proposed that the causative electrons for these bursts are accelerated in regions of reconnecting magnetic field in the wakes of coronal mass ejections (CMEs). In this paper, we examine the durations, intensities, and other characteristics of such radio bursts in the hectometric frequency range and compare them to several groups of control events. We conclude that simple criteria, based on hectometric data alone, can identify the majority (similar to80%) of type III-l radio bursts, which are associated with >20 MeV SEP proton events, while excluding almost 100% of the control events. Detailed study of these type III-l bursts may play a significant role in a better understanding of the acceleration of SEPs and of the magnetic field evolution in the vicinity of CMEs. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico. Catholic Univ Amer, Washington, DC 20064 USA. Lockheed Martin ATC, Palo Alto, CA USA. Observ Paris, Meudon, France. RP MacDowall, RJ (reprint author), NASA, Goddard Space Flight Ctr, Code 695, Greenbelt, MD 20771 USA. RI MacDowall, Robert/D-2773-2012 NR 8 TC 16 Z9 16 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 24 PY 2003 VL 30 IS 12 AR 8018 DI 10.1029/2002GL016624 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 683YE UT WOS:000183178000005 ER PT J AU Richardson, IG Lawrence, GR Haggerty, DK Kucera, TA Szabo, A AF Richardson, IG Lawrence, GR Haggerty, DK Kucera, TA Szabo, A TI Are CME "interactions" really important for accelerating major solar energetic particle events? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CORONAL MASS EJECTIONS AB [1] Recent studies have proposed that the presence or absence of an "interaction'' with a preceding coronal mass ejection (CME) or other coronal structure within 50 R-s of the Sun discriminates large, fast CMEs associated with major solar energetic particle (SEP) events from those that are not. We conclude that there is no compelling evidence that, if such interactions take place, they play an important role in SEP acceleration. Reasons include: The reported statistical results are consistent with a chance association between interacting CMEs and SEP events; Energetic SEPs are detected at Earth typically before or around the time when the "primary'' CME enters the LASCO C2 field of view - interactions higher in the corona cannot play a role in acceleration of these particles; For similar to60% of major SEP events in 1997-2001, the preceding CME fades into the background corona or is relatively narrow (< 40&DEG;), suggesting any interaction will be weak; Radio signatures attributed to CME interaction occur after SEP acceleration has commenced. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Catholic Univ Amer, Washington, DC 20064 USA. RP Richardson, IG (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Kucera, Therese/C-9558-2012; OI Richardson, Ian/0000-0002-3855-3634 NR 17 TC 10 Z9 10 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 24 PY 2003 VL 30 IS 12 AR 8014 DI 10.1029/2002GL016424 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 683YE UT WOS:000183178000001 ER PT J AU Prigent, C Aires, F Rossow, WB AF Prigent, C Aires, F Rossow, WB TI Land surface skin temperatures from a combined analysis of microwave and infrared satellite observations for an all-weather evaluation of the differences between air and skin temperatures SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE biosphere/atmosphere interactions; land/atmosphere interactions; remote sensing ID POLAR ORBITING SATELLITES; LIQUID WATER PATH; DIURNAL CYCLE; SOIL-MOISTURE; THERMAL INERTIA; ENERGY BALANCE; SSM/I; EMISSIVITIES; CLIMATE; CLOUDS AB [1] A neural network inversion scheme including first guess information has been developed to retrieve surface temperature T-s, along with atmospheric water vapor, cloud liquid water, and surface emissivities over land from a combined analysis of Special Sensor Microwave/Imager (SSM/I) and International Satellite Cloud Climatology Project (ISCCP) data. In the absence of routine in situ surface skin measurements, retrieved T-s values are evaluated by comparison to the surface air temperature T-air measured by the meteorological station network. The T-s - T-air difference shows all the expected variations with solar flux, soil characteristics, and cloudiness. During daytime the T-s - T-air difference is driven by the solar insulation, with positive differences that increase with increasing solar flux. With decreasing soil and vegetation moisture the evaporation rate decreases, increasing the sensible heat flux, thus requiring larger T-s - T-air differences. Nighttime T-s - T-air differences are governed by the longwave radiation balance, with T-s usually closer or lower than T-air. The presence of clouds dampens all the difference. After suppression of the variability associated to the diurnal solar flux variations, the T-s and T-air data sets show very good agreement in their synoptic variations, even for cloudy cases, with no bias and a global rms difference of similar to2.9 K. This value is an upper limit of the retrieval rms because it includes errors in the in situ data as well as errors related to imperfect time and space collocations between the satellite and in situ measurements. C1 Observ Paris, CNRS, LERMA, F-75014 Paris, France. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Ecole Polytech, Meteorol Dynam Lab, Palaiseau, France. RP Prigent, C (reprint author), Observ Paris, CNRS, LERMA, 61 Ave Observ, F-75014 Paris, France. EM catherine.prigent@obspm.fr; faires@giss.nasa.gov; wrossow@giss.nasa.gov RI Rossow, William/F-3138-2015 NR 49 TC 38 Z9 40 U1 2 U2 17 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 24 PY 2003 VL 108 IS D10 AR 4310 DI 10.1029/2002JD002301 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 683YP UT WOS:000183178900001 ER PT J AU Dehant, V Feissel-Vernier, M de Viron, O Ma, C Yseboodt, M Bizouard, C AF Dehant, V Feissel-Vernier, M de Viron, O Ma, C Yseboodt, M Bizouard, C TI Remaining error sources in the nutation at the submilliarc second level SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE Earth rotation; nutation; VLBI ID BASE-LINE INTERFEROMETRY; INNER CORE DYNAMICS; RIGID-EARTH; ANGULAR-MOMENTUM; FORCED NUTATIONS; RADIO INTERFEROMETRY; TORQUE APPROACH; REFERENCE-FRAME; ROTATION; VARIABILITY AB [1] Earth's precession and nutations are mainly generated by the luni-solar tidal torque. Diurnal retrograde variations in the atmospheric and oceanic angular momenta in an Earth-fixed reference system induce some additional nutation motions. Observed precession and nutations are derived from very long baseline interferometry (VLBI) data, assuming that the direction of the observed quasars are fixed in space. In this study, we consider the effects of two possible causes for explaining discrepancies between the observed nutations and those modeled in MHB2000 (model adopted by the International Astronomical Union): (1) the time variations in the atmospheric (and potentially oceanic) forcing of the nutations, of the free core nutation (FCN), and of the free inner core nutation (FICN), and (2) the possible contamination of VLBI-derived nutation amplitudes by apparent changes in the directions of the extragalactic radio sources. The robustness of MHB2000 is tested by perturbing some of the parameters and assessing the validity of the resulting nutation amplitudes against realistic estimations. We show that even allowing for large discrepancies related to atmospheric forcing, the ranges of the possible changes in the FCN and FICN periods and damping factors are small. C1 Observ Royal Belgique, B-1180 Brussels, Belgium. Observ Paris, UMR 8630, Inst Geog Natl, LAREG, F-75014 Paris, France. Inst Geog Natl, Lab Rech Geodesdie, Marne L Vallee, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Dehant, V (reprint author), Observ Royal Belgique, Ave Circularize 3, B-1180 Brussels, Belgium. EM veronique.dehant@oma.be; feissel@esgn.ign.fr; o.deviron@oma.be; cma@virgo.gsfc.nasa.gov; m.yseboodt@oma.be RI Ma, Chopo/D-4751-2012; de Viron, Olivier/N-6647-2014 OI de Viron, Olivier/0000-0003-3112-9686 NR 40 TC 23 Z9 23 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAY 24 PY 2003 VL 108 IS B5 AR 2275 DI 10.1029/2002JB001763 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 683ZD UT WOS:000183180200004 ER PT J AU Grant, WB Browell, EV Butler, CF Gibson, SC Kooi, SA von der Gathen, P AF Grant, WB Browell, EV Butler, CF Gibson, SC Kooi, SA von der Gathen, P TI Estimation of Arctic polar vortex ozone loss during the winter of 1999-2000 using vortex-averaged airborne differential absorption lidar ozone measurements referenced to N2O isopleths SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE differential absorption lidar; ozone loss; Arctic vortex; electrochemical concentration cell (ECC) ozonesondes; SOLVE/THESEO ID OBSERVATIONAL EVIDENCE; DIAL MEASUREMENTS; DEPLETION; DENITRIFICATION; STRATOSPHERE; CAMPAIGN; DESCENT; RATES; AIR AB The NASA Langley UV differential absorption lidar (DIAL) system flew on the NASA DC-8 aircraft during the Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment/Third European Stratospheric Experiment on Ozone 2000 (SOLVE/THESEO 2000) mission from 30 November 1999 to 15 March 2000. The UV DIAL system measured ozone (O-3) profiles at altitudes from about 1 km above the aircraft up to about 26 km with a vertical resolution of 750 m and a horizontal resolution of 70 km below 19 km and 140 km above 19 km. In comparison with electrochemical concentration cell ozonesonde profiles, the UV DIAL O-3 measurements agreed to within 5% up to 20 km and 10% from 20 to 25 km. Ozone loss during the season was determined using the UV DIAL O-3 data along with air mass subsidence determined using N2O as a conservative tracer at five levels from 50 to 250 ppbv [Greenblatt et al., 2002]. O-3 mixing ratios were determined inside the polar vortex, away from the collar region along these five levels during the mission. The maximum O-3 loss determined from 30 November to 12 March was 1.55+/-0. 3 ppmv at the 440-450 K potential temperature (Theta) level, while the loss there between 20 January and 15 March was 1.3+/-0.3 ppmv. These results are comparable to many of the other reported losses for these periods, but lower than several. Some of the determinations of higher losses used a different method to determine descent during the season. These results indicate that a series of vertical profiles of O-3 that sample much of the vortex during the winter, along with determinations of the descent of air masses inside the vortex, can give a reasonable estimate of the O-3 changes during the season. C1 NASA, Sci Applicat Int Corp, Langley Res Ctr, Hampton, VA 23681 USA. Alfred Wegener Inst Polar & Marine Res, Res Unit Potsdam, D-14473 Potsdam, Germany. RP Grant, WB (reprint author), NASA, Sci Applicat Int Corp, Langley Res Ctr, MS 410A, Hampton, VA 23681 USA. EM william.b.grant@nasa.gov; edward.v.browell@nasa.gov; gathen@awi-potsdam.de RI von der Gathen, Peter/B-8515-2009; Grant, William/B-8311-2009 OI von der Gathen, Peter/0000-0001-7409-1556; Grant, William/0000-0002-1439-3285 NR 41 TC 3 Z9 3 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 23 PY 2003 VL 108 IS D10 AR 4309 DI 10.1029/2002JD002668 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 683YN UT WOS:000183178800001 ER PT J AU Benson, RF Osherovich, VA Fainberg, J Reinisch, BW AF Benson, RF Osherovich, VA Fainberg, J Reinisch, BW TI Classification of IMAGE/RPI-stimulated plasma resonances for the accurate determination of magnetospheric electron density and magnetic field values SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE magnetospheric electron density; magnetospheric magnetic field strength; sounder-stimulated plasma resonances; radio plasma imager (RPI); IMAGE satellite ID DURATION GYROHARMONIC RESONANCES; CYCLOTRON-HARMONIC WAVES; IO TORUS; RELAXATION SOUNDER; TOPSIDE SOUNDERS; RADIO EMISSIONS; PHYSICAL NATURE; IONOSPHERE; FREQUENCIES; TURBULENCE AB The Radio Plasma Imager (RPI) on the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) satellite stimulates short-range plasma-wave echoes and plasma emissions, both known as local plasma resonances, that are detected on plasmagrams (virtual range versus frequency presentations of the amplitude-modulated received signals). These resonances are used to provide the local electron density N-e and magnetic field strength \B\ that are required for accurate inversions of the RPI reflection traces into magnetospheric N-e profiles. Examples are presented that have been used for this purpose and also that yield N-e gradients within a single plasmagram in the vicinity of the plasmapause and accurate (near apogee) N-e measurements during the 31 March 2001 magnetic storm. The RPI-stimulated resonances are the magnetospheric analog of plasma resonances stimulated by ionospheric topside sounders at the harmonics of the electron cyclotron frequency f(ce), the electron plasma frequency f(pe), the upper-hybrid frequency f(uh) (where f(uh)(2)=f(pe)(2)+f(ce)(2)), between nf(ce) both above and below f(pe) known as Qn and Dn resonances, respectively, and also at other frequencies. While they are observed to have an inherent bandwidth of 300 Hz or less, the effective detection bandwidth for strong resonances is nearly 2 kHz. The Qn resonances are often observed with time durations exceeding the 178 ms limit of the RPI operating programs commonly used for resonance detection. The f(uh) resonance is also observed with a long time duration even when it is in the plasma domain where it is normally weaker, i.e., when f(uh)>2f(ce). A strong resonance at f(pe) is often but not always observed. In earlier investigations, the Dn resonances had been related to natural magnetospheric plasma-wave emissions and to sounder-stimulated plasma-wave emissions in Jupiter's Io plasma torus. The present RPI observations represent the first evidence for the stimulation of these resonances by a sounder deep in the terrestrial magnetosphere. These observations suggest the possible widespread occurrence of N-e field-aligned irregularities (FAI) or the ease of sounder-stimulated FAI based on one Dn generation mechanism involving eigen modes of cylindrical plasma oscillations which have been associated with FAI. The RPI observations provide additional support to earlier suggestions that the Qn and Dn resonances have components of natural origin. The capability of simultaneous reception on three mutually orthogonal dipole receiving antennas often aids in the identification of spectral features. The RPI capability to generate magnetospheric reflection traces, leading to well-defined wave cutoff frequencies at the satellite, provides independent Ne determinations and additional spectral-identification confidence. Combining these capabilities with new analysis techniques that produce three-antenna plasmagrams normalized by f(ce) and amplitude plots based on averages over different range-bin intervals, N-e and \B\ can often be accurately determined from the plasma-resonance spectra to within uncertainties of the order of 1% and 0.1%, respectively, when RPI sounds using frequency steps equal to the 300 Hz receiver bandwidth. Such accuracy in magnetospheric N-e determination, even when N-e similar to 1 cm(-3), is difficult to attain by other techniques. It can only be obtained by RPI with proper spectral-identification. For example, identification uncertainties between f(pe) and f(uh) can lead to 20% uncertainties in N-e; even larger uncertainties can result when the N-e determinations are based solely on the Qn resonances and f(ce) when non-Maxwellian electron velocity distributions are present. Except for such frequency deviations of the Qn resonances, the main controlling factor of the plasma-resonance spectra appears to be, as in the ionosphere, the plasma parameter f(pe)/f(ce). C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, EER Syst Inc, Greenbelt, MD 20771 USA. Univ Massachusetts Lowell, Ctr Atmospher Res, Environm Earth & Atmospher Sci Dept, Lowell, MA 01854 USA. RP Benson, RF (reprint author), NASA, Goddard Space Flight Ctr, Code 692, Greenbelt, MD 20771 USA. NR 75 TC 29 Z9 29 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 MAY 23 PY 2003 VL 108 IS A5 AR 1207 DI 10.1029/2002JA009589 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 683ZG UT WOS:000183180500002 ER PT J AU Daglis, IA Kozyra, JU Kamide, Y Vassiliadis, D Sharma, AS Liemohn, MW Gonzalez, WD Tsurutani, BT Lu, G AF Daglis, IA Kozyra, JU Kamide, Y Vassiliadis, D Sharma, AS Liemohn, MW Gonzalez, WD Tsurutani, BT Lu, G TI Intense space storms: Critical issues and open disputes SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE space storms; ring current; particle acceleration; energetic oxygen; storm recovery; storm-substorm relation ID MAGNETOSPHERIC ION COMPOSITION; AURORAL ELECTROJET INDEXES; RING CURRENT DEVELOPMENT; GEOMAGNETIC STORMS; SOLAR-WIND; MAGNETIC STORMS; GEOSYNCHRONOUS ORBIT; NEUTRAL ATOMS; SUBSTORM; PHASE AB This paper addresses the question of particular characteristics and causes of intense space storms. We focus on several unresolved issues, which are critical to storm research and often nourish open disputes: the extent of interplanetary driving, the role of substorms in storm dynamics through the acceleration of particles to ring current energies, the identity of the lead agent of fast ring current decay right after storm maximum and the cause of the two-phase recovery of intense storms, the global morphology of the storm-time ring current, and the predictability of intense storms. Space storm physics has been driven by several more or less successful paradigms during the four decades following the dawn of the space flight era. However, recent suggestions and conclusions resulting from a number of observational and modeling studies have brought significant constraints to several of these paradigms. Thus for example, interplanetary driving through southward oriented magnetic fields is not always by itself sufficient to drive intense space storms because it is conditioned by internal magnetospheric conditions, the MLT distribution of storm-time magnetic disturbances is often asymmetric during the storm main phase, and charge exchange is not the lead agent of ring current decay at all times. C1 Natl Observ Athens, Inst Space Applicat & Remote Sensing, Athens 15236, Greece. Univ Michigan, Space Phys Res Lab, Ann Arbor, MI 48109 USA. Nagoya Univ, Solar Terr Environm Lab, Toyokawa 442, Japan. NASA, Goddard Space Flight Ctr, USRA, Greenbelt, MD 20771 USA. Univ Maryland, College Pk, MD 20782 USA. Inst Pesquisas Espaciais, BR-12201970 Sao Paulo, Brazil. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. RP Daglis, IA (reprint author), Natl Observ Athens, Inst Space Applicat & Remote Sensing, Athens 15236, Greece. EM daglis@space.noa.gr; jukozyra@umich.edu; kamide@stelab.nagoya-u.ac.jp; vassi@electra.gsfc.nasa.gov; ssh@astro.umd.edu; liemohn@umich.edu; gonzalez@dge.inpe.br; btsurutani@jplsp.jpl.nasa.gov; ganglu@hao.ucar.edu RI Liemohn, Michael/H-8703-2012; Daglis, Ioannis/L-6100-2013; Lu, Gang/A-6669-2011 OI Liemohn, Michael/0000-0002-7039-2631; Daglis, Ioannis/0000-0002-0764-3442; NR 86 TC 69 Z9 69 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 23 PY 2003 VL 108 IS A5 AR 1208 DI 10.1029/2002JA009722 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 683ZG UT WOS:000183180500005 ER PT J AU Tsyganenko, NA Singer, HJ Kasper, JC AF Tsyganenko, NA Singer, HJ Kasper, JC TI Storm-time distortion of the inner magnetosphere: How severe can it get? SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE inner magnetosphere; space storms; geomagnetic field; empirical modeling; partial ring current; field line deformation ID DAWN-DUSK ASYMMETRY; MAGNETOPAUSE; MODEL AB First results are presented of an effort to model the storm-time distortion of the magnetic field in the inner magnetosphere using space magnetometer data. Strong geomagnetic storms are relatively rare events, represented by only a small fraction of the data used in the derivation of existing empirical geomagnetic field models. Hence using those models for the mapping of the storm-time magnetosphere is at most an extrapolation based on trends, obtained from quiet and moderately disturbed data. To overcome that limitation, a set of data was created, containing only clear-cut events with Dst less than or equal to -65 nT, with the goal to derive models of the inner and near geomagnetic field (R<15 R-E), representing strongly disturbed geomagnetic configurations and their evolution during the storm cycle. The final data set included about 143,000 records with 5-min average B-vectors, covering 37 major storms between 1996 and 2000. Most of the data came from GOES-8, -9, -10, Polar, and Geotail spacecraft, and two storms in February-March of 1998 were also partially covered by the data of Equator-S. In all cases, only those storms were selected for which concurrent solar wind and IMF data were available for the entire duration of the event. Interplanetary medium data were provided by Wind, ACE, and, to a lesser extent, by IMP 8 and Geotail. The inner magnetospheric field was represented using the newly developed T01 model [Tsyganenko, 2002a, 2002b], with a duskside partial ring current with variable amplitude and scale size, an essential part of the storm-time current system. The modeling revealed an enormous distortion and dawn-dusk asymmetry of the inner magnetosphere during the peak of the storm main phase, caused by the combined effect of the symmetric and partial ring currents, cross-tail current, and Birkeland currents. We found that during storms with Dst < -250 nT the tail-like deformation of the nightside field penetrates so close to Earth that the quasi-dipolar approximation breaks down at distances as small as 3-4 R-E. This finding yields a quantitative answer to the question of why the auroras expand to unusually low latitudes during extremely strong storms. It also may provide a natural explanation for the observed impulsive injections and energizations of charged particles on the innermost L-shells. Finally, it questions the validity of using the dipole or quasi-dipole approximation in numerical simulations of severe storms in the inner magnetosphere. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. NOAA, Space Environm Ctr, Boulder, CO 80305 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. RP Tsyganenko, NA (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Code 695, Greenbelt, MD 20771 USA. RI Kasper, Justin/D-1152-2010; Tsyganenko, Nikolai/J-7377-2012 OI Kasper, Justin/0000-0002-7077-930X; Tsyganenko, Nikolai/0000-0002-5938-1579 NR 14 TC 146 Z9 150 U1 1 U2 9 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 23 PY 2003 VL 108 IS A5 AR 1209 DI 10.1029/2002JA009808 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 683ZG UT WOS:000183180500008 ER PT J AU Ng, HT Li, J Smith, MK Nguyen, P Cassell, A Han, J Meyyappan, M AF Ng, HT Li, J Smith, MK Nguyen, P Cassell, A Han, J Meyyappan, M TI Growth of epitaxial nanowires at the junctions of nanowalls SO SCIENCE LA English DT Article C1 NASA, Ctr Nanotechnol, Ames Res Ctr, Moffett Field, CA 94035 USA. NASA, Eloret Corp, Ames Res Ctr, Moffett Field, CA 94035 USA. San Jose State Univ, Dept Chem Engn, San Jose, CA 95192 USA. RP Ng, HT (reprint author), NASA, Ctr Nanotechnol, Ames Res Ctr, Moffett Field, CA 94035 USA. RI Li, Jun/H-7771-2013 OI Li, Jun/0000-0002-3689-8946 NR 4 TC 357 Z9 362 U1 3 U2 46 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 23 PY 2003 VL 300 IS 5623 BP 1249 EP 1249 DI 10.1126/science.1082542 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 681NN UT WOS:000183042400036 PM 12764187 ER PT J AU Chisholm, MF Wang, YH Lupini, AR Eres, G Puretzky, AA Brinson, B Melechko, AV Geohegan, DB Cui, HT Johnson, MP Pennycook, SJ Lowndes, DH Arepalli, S Kittrell, C Sivaram, S Kim, M Lavin, G Kono, J Hauge, R Smalley, RE AF Chisholm, MF Wang, YH Lupini, AR Eres, G Puretzky, AA Brinson, B Melechko, AV Geohegan, DB Cui, HT Johnson, MP Pennycook, SJ Lowndes, DH Arepalli, S Kittrell, C Sivaram, S Kim, M Lavin, G Kono, J Hauge, R Smalley, RE TI Comment on "Single crystals of single-walled carbon nanotubes formed by self-assembly" SO SCIENCE LA English DT Editorial Material ID ENERGY-LOSS SPECTROSCOPY; TERNARY C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Rice Univ, Ctr Nanoscale Sci & Technol, Houston, TX 77005 USA. NASA, GB Tech, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Geohegan, DB (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. RI Melechko, Anatoli/B-8820-2008; Hauge, Robert/A-7008-2011; Arepalli, Sivaram/A-5372-2010; Puretzky, Alexander/B-5567-2016; Geohegan, David/D-3599-2013; Eres, Gyula/C-4656-2017 OI Hauge, Robert/0000-0002-3656-0152; Puretzky, Alexander/0000-0002-9996-4429; Geohegan, David/0000-0003-0273-3139; Eres, Gyula/0000-0003-2690-5214 NR 8 TC 1 Z9 1 U1 1 U2 14 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 23 PY 2003 VL 300 IS 5623 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 681NN UT WOS:000183042400024 ER PT J AU McComas, DJ Elliott, HA Schwadron, NA Gosling, JT Skoug, RM Goldstein, BE AF McComas, DJ Elliott, HA Schwadron, NA Gosling, JT Skoug, RM Goldstein, BE TI The three-dimensional solar wind around solar maximum SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CORONAL HOLES; ULYSSES; NORTHERN AB [1] Ulysses is now completing its second solar polar orbit, dropping back down in latitude as the Sun passes through its post-maximum phase of the solar cycle. A mid-sized circumpolar coronal hole that formed around solar maximum in the northern hemisphere has persisted and produced a highly inclined CIR, which was observed from similar to70degreesN down to similar to30degreesN. We find that the speed maxima in the high-speed streams follow the same slow drop in speed with decreasing latitude observed in the large polar coronal holes around solar minimum. These results suggest a solar wind acceleration effect that is related to heliolatitude or solar rotation. We also find that the solar wind dynamic pressure is significantly lower in the post-maximum phase of this solar cycle than during the previous one, indicating that while the heliosphere is larger than near solar minimum, it should be smaller than during or after the previous maximum. C1 SW Res Inst, Space Sci & Engn Div, San Antonio, TX 78228 USA. Los Alamos Natl Lab, Grp NIS1, Los Alamos, NM 87545 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP McComas, DJ (reprint author), SW Res Inst, Space Sci & Engn Div, PO Drawer 28510, San Antonio, TX 78228 USA. NR 18 TC 134 Z9 136 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 22 PY 2003 VL 30 IS 10 AR 1517 DI 10.1029/2003GL017136 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 683YA UT WOS:000183177600007 ER PT J AU Limpasuvan, V Wu, DL AF Limpasuvan, V Wu, DL TI Two-day wave observations of UARS Microwave Limb Sounder mesospheric water vapor and temperature SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE middle atmosphere dynamics; mesosphere water vapor; mesosphere temperature; two-day wave; mesospheric waves ID 2-DAY WAVE; QUASI-2-DAY WAVE; MIDDLE ATMOSPHERE; BAROCLINIC INSTABILITY; STRATOSPHERIC ANALYSES; SUMMER MESOSPHERE; GRAVITY-WAVES; DYNAMICS; STRATOPAUSE; MLS AB [1] A two-day wave disturbance is observed in the mesospheric temperature and water vapor on the basis of new version data from the Upper Atmosphere Research Satellite Microwave Limb Sounder. Using two data segments during the austral summers (January-February of 1992 and 1993) and the asynoptic mapping method, a strong wave signal is identified as having zonal wave number 3 and a westward period of about 2.1 days. The wave amplitudes are located near the core of the summer easterly jet with strongest wave amplitudes (as large as 11 K and 0.35 part per million by volume) near the mesopause. The temperature and water vapor wave strengths are highly correlated in time, but their peaks are almost longitudinally out of phase. Poleward heat flux associated with upward wave energy propagation in the Southern Hemisphere points to baroclinic instability as the cause for the wave appearance. A growing wave signature in water vapor is observed in regions of strong meridional gradient of water vapor. Near the mesopause, wave breaking is suggested as moist polar air is displaced into the much drier subtropics and wave amplitude decays. C1 Coastal Carolina Univ, Dept Chem & Phys, Conway, SC 29528 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Limpasuvan, V (reprint author), Coastal Carolina Univ, Dept Chem & Phys, POB 261954, Conway, SC 29528 USA. EM var@coastal.edu; dwu@mls.jpl.nasa.gov RI Limpasuvan, Varavut/K-6266-2013; Wu, Dong/D-5375-2012 NR 45 TC 26 Z9 26 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 22 PY 2003 VL 108 IS D10 AR 4307 DI 10.1029/2002JD002903 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 683YM UT WOS:000183178700003 ER PT J AU Wang, C Richardson, JD Burlaga, LF Ness, NF AF Wang, C Richardson, JD Burlaga, LF Ness, NF TI On radial heliospheric magnetic fields: Voyager 2 observation and model SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE interplanetary magnetic fields; solar wind plasma ID ULYSSES; 1-AU AB The heliospheric magnetic field (HMF) direction, on average, conforms well to the Parker spiral. However, numerous examples of events where the HMF is oriented in near-radial directions for many hours have been reported on the basis of observations inside 5 AU from spacecraft such as ISEE-3 and Ulysses. The magnetic field data observed by Voyager 2 from launch in 1977 through the end of 1982 (i.e., between 1 and similar to10 AU) were searched for all instances of radial fields with durations of 6 hours or more. Radial fields of significant durations at large distances are unusual as the Parker spiral is very tightly wound. The radial HMF events in the inner heliosphere typically occur at times when the solar wind speed is declining gradually, while they tend to be associated with steady wind speeds at distances beyond similar to6 AU. The durations of these events appear to be independent of distance and solar cycle, with an average duration of similar to11 hours. They generally are not associated with interplanetary coronal mass ejections (ICMEs). Possible generation mechanisms of the radial field events related to speed variations near the Sun are investigated by use of a MHD model. We find that a noticeable low-speed plateau of limited duration in solar wind speed near the Sun can produce radial field events having durations of the order of 10 hours in the heliosphere as observed by Voyager 2. C1 Chinese Acad Sci, Lab Space Weather, Beijing 100080, Peoples R China. MIT, Ctr Space Res, Cambridge, MA 02139 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. RP Wang, C (reprint author), Chinese Acad Sci, Lab Space Weather, POB 8701, Beijing 100080, Peoples R China. EM cw@spaceweather.ac.cn; jdr@space.mit.edu; Leonard.F.Burlaga@nasa.gov; nfness@udel.edu NR 27 TC 6 Z9 7 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 22 PY 2003 VL 108 IS A5 AR 1205 DI 10.1029/2002JA009809 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 683ZF UT WOS:000183180400002 ER PT J AU Cane, HV Erickson, WC AF Cane, HV Erickson, WC TI Energetic particle propagation in the inner heliosphere as deduced from low-frequency (< 100 kHz) observations of type III radio bursts SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE energetic particles; radio emissions; flares; energetic particle transport ID MODEL INTERPRETATION; MAGNETIC-FIELD; SOLAR-FLARES; COSMIC-RAY; WIND AB [1] Solar energetic particle (SEP) events are well-associated with solar flares. It is observed that the delay between the time of the flare and the first-arriving particles at a spacecraft increases with increasing difference between the flare longitude and the foot point of the field line on which the spacecraft is located. This difference we call the "connection angle'' and can be as large as similar to120degrees. Recently it has been found that all SEP events are preceded by type III radio bursts. These bursts are plasma emission caused by the propagation of 2-50 keV flare electrons through the solar corona and into the solar wind. The drift of these type III radio bursts to lower and lower frequencies enables the propagation of the flare electrons to be traced from the Sun to about 1 AU. We have made an extensive analysis of the type III bursts associated with >20 MeV proton events and find that, in most cases, the radio emission extends to the local plasma frequency when the energetic particles arrive within a few hours of the flare. We conclude that this emission at the lowest possible frequency is generated close to the spacecraft. We then use the time from when the burst started at the Sun to when it reached the local plasma frequency to infer the time it took the radio producing electrons to travel to the spacecraft. We find that these delay times are organized by the connection angle and correlate with the proton delay times. We also find that the differences between the radio delays at Wind and Ulysses are matched by differences in the relative arrival times of the energetic particles at the two spacecraft. The consistent timing between the relative arrival times of energetic electrons and protons and the start of the lowest frequency radio emissions suggests that the first arriving particles of both species are accelerated as part of the flare process and that they propagate to the spacecraft along trajectories similar to those of the lower-energy flare electrons. To be detected by observers at locations distant from the nominal field lines originating in the flaring regions the particles must undergo lateral transport. The continuity of the radio bursts suggests that the cross-field transport occurs in the interplanetary medium. C1 NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Bruny Isl Radio Spectrometer, Bruny Isl, Tas 7150, Australia. RP Cane, HV (reprint author), NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM hilary.cane@utas.edu.au; bill.erickson@utas.edu.au NR 28 TC 28 Z9 28 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 21 PY 2003 VL 108 IS A5 AR 1203 DI 10.1029/2002JA009488 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 683ZE UT WOS:000183180300003 ER PT J AU Barstow, MA Good, SA Holberg, JB Hubeny, I Bannister, NP Bruhweiler, FC Burleigh, MR Napiwotzki, R AF Barstow, MA Good, SA Holberg, JB Hubeny, I Bannister, NP Bruhweiler, FC Burleigh, MR Napiwotzki, R TI Heavy-element abundance patterns in hot DA white dwarfs SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE stars : abundances; white dwarfs; ultraviolet : stars ID ULTRAVIOLET EXPLORER SURVEY; MASS-DISTRIBUTION; GD 394; EQUILIBRIUM ABUNDANCES; RADIATIVE LEVITATION; LUMINOSITY FUNCTION; MODEL ATMOSPHERES; G191-B2B; STARS; HELIUM AB We present a series of systematic abundance measurements for 25 hot DA white dwarfs in the temperature range similar to20000-110000 K, based on far-ultraviolet spectroscopy with the Space Telescope Imaging Spectrograph (STIS)/Goddard High Resolution Spectrograph (GHRS) on-board Hubble Space Telescope , IUE and FUSE . Using our latest heavy-element blanketed non-local thermodynamic equilibrium (non-LTE) stellar atmosphere calculations we have addressed the heavy-element abundance patterns, making completely objective measurements of abundance values and upper limits using a chi(2) fitting technique to determine the uncertainties in the abundance measurements, which can be related to the formal upper limits in those stars where particular elements are not detected. We find that the presence or absence of heavy elements in the hot DA white dwarfs largely reflects what would be expected if radiative levitation is the supporting mechanism, although the measured abundances do not match the predicted values very well, as reported by other authors in the past. Almost all stars hotter than similar to50 000 K contain heavy elements. For most of these the spread in element abundances is quite narrow and similar to the abundances measured in G191-B2B. However, there is an unexplained dichotomy at lower temperatures with some stars having apparently pure H envelopes and others having detectable quantities of heavy elements. The heavy elements present in these cooler stars are often stratified, lying in the outermost layers of the envelope. A few strong temperature/evolutionary effects are seen in the abundance measurements. There is a decreasing Si abundance with temperature, the N abundance pattern splits into two groups at lower temperature and there is a sharp decline in Fe and Ni abundance to zero, below similar to50 000 K. When detected, the Fe and Ni abundances maintain an approximately constant ratio, close to the cosmic value of similar to20. For the hottest white dwarfs observed by STIS, the strongest determinant of abundance appears to be gravity. C1 Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20711 USA. Catholic Univ Amer, Dept Phys, IACS, Washington, DC 20064 USA. Dr Remeis Sternwarte, D-96049 Bamberg, Germany. RP Barstow, MA (reprint author), Univ Leicester, Dept Phys & Astron, Univ Rd, Leicester LE1 7RH, Leics, England. EM mab@star.le.ac.uk NR 71 TC 58 Z9 58 U1 0 U2 2 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 21 PY 2003 VL 341 IS 3 BP 870 EP 890 DI 10.1046/j.1365-8711.2003.06462.x PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 676ZR UT WOS:000182782900018 ER PT J AU Whiteman, DN AF Whiteman, DN TI Examination of the traditional Raman lidar technique. 1. Evaluating the temperature-dependent lidar equations SO APPLIED OPTICS LA English DT Article ID PHYSICAL PARTICLE PROPERTIES; AEROSOL EXTINCTION PROFILES; ELASTIC-BACKSCATTER LIDAR; TROPICAL INDIAN-OCEAN; WATER-VAPOR; RAYLEIGH-SCATTERING; CROSS-SECTIONS; OPTICAL-PROPERTIES; CIRRUS CLOUDS; ATMOSPHERE AB The essential information required for the analysis of Raman lidar water vapor and aerosol data acquired by use of a single laser wavelength is compiled here and in a companion paper [Appl. Opt. 42, 2593 (2003)]. Various details concerning the evaluation of the lidar equations when Raman scattering is measured are covered. These details include the influence of the temperature dependence of both pure rotational and vibrational-rotational Raman scattering on the lidar profile. The full temperature dependence of the Rayleigh-Mie and Raman lidar equations are evaluated by use of a new form of the lidar equation where all the temperature dependence is carried in a single term. The results indicate that, for the range of temperatures encountered in the troposphere, the magnitude of the temperature-dependent effect can reach 10% or more for narrowband Raman water-vapor measurements. Also, the calculation of atmospheric transmission, including the effects of depolarization, is examined carefully. Various formulations of Rayleigh cross-section determination commonly used in the lidar field are compared and reveal differences of as much as 5% among the formulations. The influence of multiple scattering on the measurement of aerosol extinction with the Raman lidar technique is considered, as Eire several photon pulse pileup-correction techniques. (C) 2003 Optical Society of America. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM david.n.whiteman@nasa.gov NR 75 TC 96 Z9 98 U1 0 U2 5 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAY 20 PY 2003 VL 42 IS 15 BP 2571 EP 2592 DI 10.1364/AO.42.002571 PG 22 WC Optics SC Optics GA 680KU UT WOS:000182977300001 PM 12776994 ER PT J AU Whiteman, DN AF Whiteman, DN TI Examination of the traditional Raman lidar technique. II. Evaluating the ratios for water vapor and aerosols SO APPLIED OPTICS LA English DT Article ID PHYSICAL PARTICLE PROPERTIES; TROPICAL INDIAN-OCEAN; CROSS-SECTIONS; TEMPERATURE; EXTINCTION; BACKSCATTER; ATMOSPHERE; CLOUDS; SYSTEM AB In a companion paper [Appl. Opt. 42, 2571 (2003)] the temperature dependence of Raman scattering and its influence on the Raman and Rayleigh-Mie lidar equations were examined. New forms of the lidar equation were developed to account for this temperature sensitivity. Here those results are used to derive the temperature-dependent forms of the equations for the water-vapor mixing ratio, the aerosol scattering ratio, the aerosol backscatter coefficient, and the extinction-to-backscatter ratio. The error equations are developed, the influence of differential transmission is studied, and several laser sources are considered in the analysis. The results indicate that the temperature functions become significant when narrowband detection is used. Errors of 5% and more can be introduced into the water-vapor mixing ratio calculation at high altitudes, and errors larger than 10% are possible for calculations of aerosol scattering ratio and thus of aerosol backscatter coefficient and of extinction-to-backscatter ratio. (C) 2003 Optical Society of America. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Whiteman, DN (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM david.n.whiteman@nasa.gov NR 42 TC 89 Z9 93 U1 0 U2 6 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 2003 VL 42 IS 15 BP 2593 EP 2608 DI 10.1364/AO.42.002593 PG 16 WC Optics SC Optics GA 680KU UT WOS:000182977300002 PM 12776995 ER PT J AU Lee, YK Yang, P Mishchenko, MI Baum, BA Hu, YX Huang, HL Wiscombe, WJ Baran, AJ AF Lee, YK Yang, P Mishchenko, MI Baum, BA Hu, YX Huang, HL Wiscombe, WJ Baran, AJ TI Use of circular cylinders as surrogates for hexagonal pristine ice crystals in scattering calculations at infrared wavelengths SO APPLIED OPTICS LA English DT Article ID DISCRETE-DIPOLE APPROXIMATION; SOLAR RADIATIVE PROPERTIES; DIFFERENCE TIME-DOMAIN; T-MATRIX METHOD; CIRRUS CLOUDS; LIGHT-SCATTERING; OPTICAL-PROPERTIES; SINGLE-SCATTERING; CLIMATE MODELS; ACCURATE PARAMETERIZATION AB We investigate the errors associated with the use of circular cylinders as surrogates for hexagonal columns in computing the optical properties of pristine ice crystals at infrared (8-12 mum) wavelengths. The equivalent circular cylinders are specified in terms of volume (V), projected area (A), and volume-to-area ratio that are equal to those of the hexagonal columns. We use the T-matrix method to compute the optical properties of the equivalent circular cylinders. We apply the finite-difference time-domain method to compute the optical properties of hexagonal ice columns smaller than 40 mum. For hexagonal columns larger than 40 mum we employ an improved geometric optics method and a stretched scattering potential technique developed in previous studies to calculate the phase function and the extinction (or absorption) efficiency, respectively. The differences between the results for circular cylinders and hexagonal columns are of the order of a few percent. Thus it is quite reasonable to use a circular cylinder geometry as a surrogate for pristine hexagonal ice columns for scattering calculations at infrared (8-12 mum) wavelengths. Although the pristine ice crystals can be approximated as circular cylinders in scattering calculations at infrared wavelengths, it is shown that optical properties of individual aggregates cannot be well approximated by those of individual finite columns or cylinders. (C) 2003 Optical Society of America. C1 Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. Met Off, Bracknell RG12 2SZ, Berks, England. RP Yang, P (reprint author), Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. EM pyang@ariel.met.tamu.edu RI Yang, Ping/B-4590-2011; Baum, Bryan/B-7670-2011; Wiscombe, Warren/D-4665-2012; Hu, Yongxiang/K-4426-2012; LEE, YONG-KEUN/A-1352-2015; Mishchenko, Michael/D-4426-2012 OI Baum, Bryan/0000-0002-7193-2767; Wiscombe, Warren/0000-0001-6844-9849; NR 62 TC 22 Z9 22 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 2003 VL 42 IS 15 BP 2653 EP 2664 DI 10.1364/AO.42.002653 PG 12 WC Optics SC Optics GA 680KU UT WOS:000182977300007 PM 12777000 ER PT J AU Hoge, FE Lyon, PE Swift, RN Yungel, JK Abbott, MR Letelier, RM Esaias, WE AF Hoge, FE Lyon, PE Swift, RN Yungel, JK Abbott, MR Letelier, RM Esaias, WE TI Validation of Terra-MODIS phytoplankton chlorophyll fluorescence line height. I. Initial airborne lidar results SO APPLIED OPTICS LA English DT Article ID INHERENT OPTICAL-PROPERTIES; DISSOLVED ORGANIC-MATTER; ABSORPTION-COEFFICIENT; IMAGING SPECTROMETER; SPATIAL VARIABILITY; OCEAN; RETRIEVAL; IMAGERY; MERIS AB The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra spacecraft contains spectral bands that allow retrieval of solar-induced phytoplankton chlorophyll fluorescence emission radiance. Concurrent airborne laser-induced (and water-Raman normalized) phytoplankton chlorophyll fluorescence data is used to successfully validate the MODIS chlorophyll fluorescence line height (FLH) retrievals within Gulf Stream, continental slope, shelf, and coastal waters of the Middle Atlantic Bight portion of the western North Atlantic Ocean for 11 March 2002. Over the entire similar to480-km flight line a correlation coefficient of r(2) = 0.85 results from regression of the airborne laser data against the MODIS FLH. It is also shown that the MODIS FLH product is not influenced by blue-absorbing chromophoric dissolved organic matter absorption. These regional results strongly suggest that the FLH methodology is equally valid within similar oceanic provinces of the global oceans. (C) 2003 Optical Society of America. C1 NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. EC&G Inc, Wallops Flight Facil, Wallops Isl, VA 23337 USA. Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20774 USA. RP Hoge, FE (reprint author), NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. EM hoge@osb.wff.nasa.gov RI Letelier, Ricardo/A-6953-2009 OI Letelier, Ricardo/0000-0003-3376-4026 NR 19 TC 21 Z9 27 U1 0 U2 10 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 2003 VL 42 IS 15 BP 2767 EP 2771 DI 10.1364/AO.42.002767 PG 5 WC Optics SC Optics GA 680KU UT WOS:000182977300022 PM 12777014 ER PT J AU Stapelfeldt, KR Menard, F Watson, AM Krist, JE Dougados, C Padgett, DL Brandner, W AF Stapelfeldt, KR Menard, F Watson, AM Krist, JE Dougados, C Padgett, DL Brandner, W TI Hubble Space Telescope WFPC2 imaging of the disk and jet of HV Tauri C SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : general; circumstellar matter; stars : individual (HV Tauri); stars : pre-main-sequence ID ON CIRCUMSTELLAR DISK; HERBIG-HARO FLOW; YOUNG STARS; INTERSTELLAR GRAINS; BINARY STARS; RADIO SURVEY; DARK CLOUD; LOW-MASS; HH 30; ACCRETION AB We have obtained Hubble Space Telescope (HST) WFPC2 images of the HV Tauri young triple system. The tertiary star appears as a compact bipolar nebula at visual wavelengths as already known in the near-infrared. New, deeper adaptive optics observations made at the Canada-France-Hawaii Telescope show no point source in the nebula to a limiting magnitude of K > 15. The results therefore confirm that HV Tau C is an optically thick circumstellar disk seen close to edge-on. Clear evidence for small, chromatic dust particles in the outer disk is provided by the color structure of the nebula: the thickness of the central dust lane shrinks by 30% between 0.55 and 2.2 mum. Bipolar jets extending 0."3-0."7 perpendicular to the dust lane are seen in HST narrowband [S II] and [O I] images. The continuum images are compared to multiple scattering models, with optimal density model parameters derived through chi(2) minimization. A disk density distribution provides a reasonable fit to the K-band image but is unable to reproduce the vertical extent of the nebula at I band without resorting to an unreasonably large scale height. Adding an envelope structure around the disk results in a much better fit to the HST image, and with a physically reasonable disk scale height. Our preferred model has a disk outer radius of 50 AU, inclination of 6degrees, and scale height of 6.5 AU at r = 50 AU. The thickness of the dark lane establishes a disk mass near 2 x 10(-3) M. (similar to2 M(Jup)) of dust and gas, if the dust grains have interstellar properties and remain fully mixed vertically. The envelope, with a much smaller mass similar to4 x 10(-5) M., would be very short-lived unless replenished by new material from the star or surrounding medium. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Observ Grenoble, Astrophys Lab, F-38041 Grenoble 9, France. Univ Nacl Autonoma Mexico, Astron Inst, Morelia 58089, Michoacan, Mexico. Space Telescope Sci Inst, Baltimore, MD 21218 USA. CALTECH, SIRTF Sci Ctr, Pasadena, CA 91125 USA. Max Planck Inst Astron, D-69117 Heidelberg, Germany. RP Stapelfeldt, KR (reprint author), CALTECH, Jet Prop Lab, Mail Stop 183-900,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM krs@exoplanet.jpl.nasa.gov RI Stapelfeldt, Karl/D-2721-2012 NR 47 TC 61 Z9 61 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 20 PY 2003 VL 589 IS 1 BP 410 EP 418 DI 10.1086/374374 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 679VW UT WOS:000182943500032 ER PT J AU Lehner, N Fullerton, AW Massa, D Sembach, KR Zsargo, J AF Lehner, N Fullerton, AW Massa, D Sembach, KR Zsargo, J TI Far Ultraviolet Spectroscopic Explorer snapshot survey of O vi variability in the winds of 66 OB-type stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE line : profiles; stars : early-type; stars : mass loss; stars : winds, outflows; ultraviolet : stars ID LARGE-MAGELLANIC-CLOUD; DRIVEN STELLAR WINDS; SPECTRAL CLASSIFICATIONS; B-SUPERGIANTS; X-RAYS; SPACE DISTRIBUTION; VELOCITIES; IONIZATION; ATLAS AB We have used the Far Ultraviolet Spectroscopic Explorer to conduct a snapshot survey of O VI variability in the winds of 66 OB-type stars in the Galaxy and the Magellanic Clouds. These time series consist of two or three observations separated by intervals ranging from a few days to several months. Although these time series provide the bare minimum of information required to detect variations, this survey demonstrates that the O VI doublet in the winds of OB-type stars is variable on various scales in both time and velocity. For spectral types from O3 to B1, 64% vary in time. At spectral types later than B1, no wind variability is observed. In view of the limitations of this survey, this fraction represents a lower limit on the true incidence of variability in the O VI wind lines, which is very common and probably ubiquitous. In contrast, for S IV and P V, only a small percentage of the whole sample shows wind variations, although this may be principally due to selection effects. The observed variations extend over several hundreds of kilometers per second of the wind pro. le and can be strong. The width over which the wind O VI profile varies is only weakly correlated with the terminal velocity (v(infinity)), but a significant correlation (close to a 1 : 1 relationship) is derived between the maximum velocity of the variation and v(infinity). High-velocity O VI wind absorption features (possibly related to the discrete absorption components seen in other wind lines) are also observed in 46% of the cases for spectral types from O3 to B0.5. These features are variable, but the nature of their propagation cannot be determined from this survey. If X-rays can produce sufficient O VI by Auger ionization of O VI and the X-rays originate from strong shocks in the wind, this study suggests that stronger shocks occur more frequently near v(infinity), causing an enhancement of O VI near v(infinity). C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 3P6, Canada. NASA, SGT Inc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Lehner, N (reprint author), Univ Wisconsin, Dept Astron, 475 N Charter St, Madison, WI 53706 USA. NR 53 TC 7 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 MAY 20 PY 2003 VL 589 IS 1 BP 526 EP 542 DI 10.1086/374550 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 679VW UT WOS:000182943500043 ER PT J AU Fortney, JJ Sudarsky, D Hubeny, I Cooper, CS Hubbard, WB Burrows, A Lunine, JI AF Fortney, JJ Sudarsky, D Hubeny, I Cooper, CS Hubbard, WB Burrows, A Lunine, JI TI On the indirect detection of sodium in the atmosphere of the planetary companion to HD 209458 SO ASTROPHYSICAL JOURNAL LA English DT Article DE planetary systems; radiative transfer; stars : individual ( HD 209458) ID EXTRASOLAR GIANT PLANETS; TRANSMISSION SPECTRA; TRANSITS; NM AB Using a self-consistent atmosphere code, we construct a new model of the atmosphere of the transiting extrasolar giant planet HD 209458b to investigate the disparity between the observed strength of the sodium absorption feature at 589 nm and the predictions of previous models. For the atmospheric temperature-pressure profile we derive, silicate and iron clouds reside at a pressure of several millibars in the planet's atmosphere. These clouds have significant vertical extent and optical depth because of our slant viewing geometry and lead to increased absorption in bands directly adjacent to the sodium line core. Using a non-LTE sodium ionization model that includes photoionization by stellar UV flux, collisional processes with H-2, and radiative recombination, we show that the ionization depth in the planet's atmosphere reaches similar to1/2 mbar at the day/night terminator. Ionization leads to a slight weakening of the sodium feature. We present our baseline model, including ionization and clouds, which falls near the observational error bars. The sensitivity of our conclusions to the derived atmospheric temperature-pressure profile is discussed. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Arizona, Dept Astron, Tucson, AZ 85721 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Opt Astron Observ, Tucson, AZ 85725 USA. RP Fortney, JJ (reprint author), Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. OI Fortney, Jonathan/0000-0002-9843-4354 NR 24 TC 79 Z9 79 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2003 VL 589 IS 1 BP 615 EP 622 DI 10.1086/374387 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 679VW UT WOS:000182943500048 ER PT J AU Whang, YC Burlaga, LF Wang, YM Sheeley, NR AF Whang, YC Burlaga, LF Wang, YM Sheeley, NR TI Solar wind speed and temperature outside 10 AU and the termination shock SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; shock waves; solar wind ID LOCAL INTERSTELLAR-MEDIUM; PRESSURE-BALANCED STRUCTURES; ANOMALOUS COSMIC-RAYS; PICKUP PROTONS; VOYAGER-2 OBSERVATIONS; OUTER HELIOSPHERE; NEUTRAL HYDROGEN; DISTANCE; MODEL; GAS AB In this paper we first present a series of pickup proton solar wind solutions following the fluid motion in the upwind direction to show that the wind speed V and temperature T, at a given r outside 10 AU, are primarily functions of the 1 AU wind speed V-0. This relationship is attributed to the accumulated effects of the pickup proton process on the heating and deceleration of the solar wind. Because pickup protons are expected to have similar effects on the solar wind at all latitudes in the upwind side of the heliosphere, in the second part of the paper, the two formulae V( r, V-0) and T( r, V-0) are extended to study the termination shock at 35degrees latitude. Wang and Sheeley have an empirical model for calculating the 1 AU wind speed V-0 from the observed photospheric field. We use the simulated wind speed V-0 to calculate V and T outside 60 AU following the fluid motion; then we can study the solar cycle variation of the termination shock. The shock location near 35degrees is unambiguously dependent on the solar cycle, with a period of approximately 1 solar cycle; the amplitude for variation of the shock location is greater than 50 AU. The new result supports the idea that the first encounter of Voyager 1 with the termination shock may occur during the declining phase of cycle 23. After the first encounter, the spacecraft will cross the shock two more times over a period of 8 years. C1 Catholic Univ Amer, Dept Mech Engn, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USN, EO Hulburt Ctr Space Res, Res Lab, Washington, DC 20375 USA. RP Whang, YC (reprint author), Catholic Univ Amer, Dept Mech Engn, Washington, DC 20064 USA. NR 42 TC 19 Z9 19 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2003 VL 589 IS 1 BP 635 EP 643 DI 10.1086/374595 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 679VW UT WOS:000182943500050 ER PT J AU Jones, HP Branston, DD Jones, PB Popescu, MD AF Jones, HP Branston, DD Jones, PB Popescu, MD TI Comparison of total solar irradiance with NASA/National Solar Observatory Spectromagnetograph data in solar cycles 22 and 23 SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : activity; Sun : magnetic fields ID SOLAR-CYCLE-22; VARIABILITY; DEPENDENCE; SPECTRUM; MODEL AB NASA/National Solar Observatory Spectromagnetograph (SPM) data are compared with spacecraft measurements of total solar irradiance (TSI) variations for 8 yr beginning with the declining phase of solar cycle 22 and extending into the maximum of cycle 23. Previously reported conclusions based on a similar comparison for a shorter time period appear to be robust: three factors (sunspots, strong unipolar regions, and strong mixed-polarity regions) describe most of the variation in the SPM record, but only the first two are associated with TSI. Additionally, the residuals of a linear multiple regression of TSI against SPM observations over the entire 8 yr period show an unexplained, increasing, linear time variation with a rate of about 0.05 W m(-2) yr(-1). Separate regressions for the periods before and after 1996 January 1 show no unexplained trends but differ substantially in regression parameters. This behavior may reflect a solar source of TSI variations beyond sunspots or uncompensated nonsolar effects in one or both of the TSI and SPM data sets. C1 NASA, Goddard Space Flight Ctr, Natl Solar Observ, Lab Astron & Solar Phys,SW Solar Stn, Tucson, AZ 85726 USA. Natl Solar Observ, Tucson, AZ 85726 USA. Univ Arizona, Ctr Informat & Comp Technol, Tucson, AZ 85721 USA. Romanian Acad, Astron Inst, RO-75212 Bucharest 28, Romania. RP Jones, HP (reprint author), NASA, Goddard Space Flight Ctr, Natl Solar Observ, Lab Astron & Solar Phys,SW Solar Stn, POB 26732, Tucson, AZ 85726 USA. NR 21 TC 11 Z9 11 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2003 VL 589 IS 1 BP 658 EP 664 DI 10.1086/374413 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 679VW UT WOS:000182943500052 ER PT J AU Hathaway, DH Nandy, D Wilson, RM Reichmann, EJ AF Hathaway, DH Nandy, D Wilson, RM Reichmann, EJ TI Evidence that a deep meridional flow sets the sunspot cycle period SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : activity; Sun : interior; Sun : magnetic fields ID SEATED GENERATING LAYER; TOROIDAL MAGNETIC-FIELD; MAIN-SEQUENCE STARS; SOLAR DYNAMO; DIFFERENTIAL ROTATION; CHROMOSPHERIC VARIATIONS; STOCHASTIC FLUCTUATIONS; MODEL; FLUX; SUN AB Sunspots appear on the Sun in two bands on either side of the equator that drift toward lower latitudes as each sunspot cycle progresses. We examine the drift of the centroid of the sunspot area toward the equator in each hemisphere from 1874 to 2002 and find that the drift rate slows as the centroid approaches the equator. We compare the drift rate at sunspot cycle maximum with the period of each cycle for each hemisphere and find a highly significant anticorrelation: hemispheres with faster drift rates have shorter periods. These observations are consistent with a meridional counter flow deep within the Sun as the primary driver of the migration toward the equator and the period associated with the sunspot cycle. We also find that the drift rate at maximum is significantly correlated with the amplitude of the following cycle, a prediction of dynamo models that employ a deep meridional flow toward the equator. Our results indicate an amplitude of about 1.2 m s(-1) for the meridional flow velocity at the base of the solar convection zone. C1 NASA, NSSTC, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. Montana State Univ, Dept Phys, Bozeman, MT 59717 USA. RP Hathaway, DH (reprint author), NASA, NSSTC, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. NR 43 TC 100 Z9 101 U1 1 U2 6 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2003 VL 589 IS 1 BP 665 EP 670 DI 10.1086/374393 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 679VW UT WOS:000182943500053 ER PT J AU Georganopoulos, M Kazanas, D AF Georganopoulos, M Kazanas, D TI Relativistic and slowing down: The flow in the hot spots of powerful radio galaxies and quasars SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; quasars : general; radiation mechanisms : nonthermal; X-rays : galaxies ID INVERSE COMPTON-SCATTERING; X-RAY-EMISSION; COMPLETE SAMPLE; CYGNUS-A; PICTOR-A; JETS; STATISTICS; SPECTRUM; HOTSPOTS; LINES AB Pairs of radio-emitting jets with lengths up to several hundred kiloparsecs emanate from the central region ( the "core") of radio-loud active galaxies. In the most powerful of them, these jets terminate in the "hot spots," compact high-brightness regions, where the jet flow collides with the intergalactic medium (IGM). Although it has long been established that in their inner (similar to1 pc) regions these jet flows are relativistic, it is still not clear if they remain so at their largest ( hundreds of kiloparsecs) scales. We argue that the X-ray, optical, and radio data of the hot spots, despite their at-first-sight disparate properties, can be unified in a scheme involving a relativistic flow upstream of the hot spot that decelerates to the subrelativistic speed of its inferred advance through the IGM and viewed at different angles to its direction of motion. This scheme, besides providing an account of the hot spot spectral properties with jet orientation, also suggests that the large-scale jets remain relativistic all the way to the hot spots. C1 NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Georganopoulos, M (reprint author), NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 31 TC 63 Z9 64 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 2003 VL 589 IS 1 BP L5 EP L8 DI 10.1086/375796 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 679WA UT WOS:000182943900002 ER PT J AU Teegarden, BJ Pravdo, SH Hicks, M Lawrence, K Shaklan, SB Covey, K Fraser, O Hawley, SL McGlynn, T Reid, IN AF Teegarden, BJ Pravdo, SH Hicks, M Lawrence, K Shaklan, SB Covey, K Fraser, O Hawley, SL McGlynn, T Reid, IN TI Discovery of a new nearby star SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : distances ID DWARFS AB We report the discovery of a nearby star with a very large proper motion of 5."05 +/- 0."03 yr(-1). The star is called SO 025300.5 +/- 165258 and referred to herein as a high proper motion star (HPMS). The discovery came as a result of a search of the SkyMorph database, a sensitive and persistent survey that is well suited for finding stars with high proper motions. There are currently only seven known stars with proper motions greater than 5" yr(-1). The spectrum and measured tangential velocity indicate that the HPMS is a main-sequence star with spectral type M6.5. Trigonometric and photometric parallaxes have been determined, yielding distance estimates of 2.4(-0.4)(+0.7) pc (lower limit) and 3.6 +/- 0.4 pc, respectively. If the former is correct, the HPMS ranks third in the list of nearest stellar systems. If the latter is correct, it is 17th. A more precise trigonometric parallax measurement is expected to be completed near the end of the year. C1 NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Teegarden, BJ (reprint author), NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. OI Covey, Kevin/0000-0001-6914-7797 NR 9 TC 45 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 MAY 20 PY 2003 VL 589 IS 1 BP L51 EP L53 DI 10.1086/375803 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 679WA UT WOS:000182943900013 ER PT J AU Walch, SP AF Walch, SP TI The bonding of N(2) to models of a (9,0) carbon nanotube and graphite SO CHEMICAL PHYSICS LETTERS LA English DT Article ID BASIS-SETS; HYDROGEN; BUNDLES AB We have studied the bonding of N(2) to a (9, 0) carbon nanotube using the MP2 and ONIOM methods with extended basis sets. We find a weak dispersion type bond with the N(2) similar to3.3 Angstrom away from the surface. Our best estimate of the binding energy, including the effect of expanding the high accuracy piece from ethylene to cluster A. is 1.88 kcal/mol for bonding in a twofold site and 1.97 kcal/mol for bonding in a sixfold site. We find N(2) is bound more strongly to a graphitic surface by similar to0.3 kcal/mol. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, ELORET, Moffett Field, CA 94035 USA. RP Walch, SP (reprint author), NASA, Ames Res Ctr, ELORET, Mail Stop 230-3, Moffett Field, CA 94035 USA. EM swalch@mail.arc.nasa.gov NR 15 TC 14 Z9 14 U1 0 U2 2 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 20 PY 2003 VL 373 IS 3-4 BP 422 EP 425 DI 10.1016/S0009-2614(03)00624-9 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 681BG UT WOS:000183016300029 ER PT J AU Wannebo, A Rosenzweig, C AF Wannebo, A Rosenzweig, C TI Remote sensing of US cornbelt areas sensitive to the El Nino-Southern Oscillation SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID DIFFERENCE VEGETATION INDEX; CLIMATIC INFORMATION; YIELD ASSESSMENT; NOAA AVHRR; NDVI; TEMPERATURE; AFRICA; PRECIPITATION; VARIABILITY; ENSO AB A 16-year time-series (1982-1997) of monthly maximum Normalized Difference Vegetation Index (NDVI) values derived from coarse-scale Advanced Very High Resolution Radiometer (AVHRR) satellite images was investigated for its application in identifying agricultural regions sensitive to El Nino-Southern Oscillation (ENSO) impacts. Cumulative NDVI values over the growing season were used to test the temporal and spatial sensitivity of rainfed agricultural regions in the US cornbelt to ENSO climate teleconnections. The correlation (R) between NDVI anomalies and yield anomalies aggregated to the Agricultural Statistics Division (ASD) level was 0.59 (significant at the 99% level). Sea surface temperatures (SSTs) from the NINO3 region (between +5.0degrees and -5.0degrees latitude and 90.0degrees and 180.0degrees west longitude in the Pacific Ocean), an indicator of the ENSO phenomenon, were significantly but weakly correlated with growing season NDVI anomalies, precipitation anomalies, and yield anomalies. Two classification schemes for El Nino, La Nina and Neutral years related to the crop growing season were applied-one based on simultaneous Pacific NINO3 SSTs (spring-summer), and one based on following winter Pacific NINO3 SSTs. The strongest differences in Vegetation Condition Index (VCI) spatial patterns among the three ENSO categories were found using the following winter SST classification. Classification of ENSO years is a key issue in analysing ENSO impacts on agriculture as represented by the NDVI, because the regularity of annual agricultural seasons is not synchronous with the quasi-regular Pacific SST cycles. C1 Goddard Inst Space Studies, New York, NY 10025 USA. RP Wannebo, A (reprint author), Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. NR 28 TC 12 Z9 12 U1 0 U2 4 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 2003 VL 24 IS 10 BP 2055 EP 2067 DI 10.1080/01431160210154786 PG 13 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 676MM UT WOS:000182755900005 ER PT J AU Liu, L Duraj, S Fanwick, PE Andras, MT Hepp, AF AF Liu, L Duraj, S Fanwick, PE Andras, MT Hepp, AF TI Substituted imidazole copper(II) complexes: The coordination polymer complex tetrakis N-methylimidazole copper(II) sulfate SO JOURNAL OF COORDINATION CHEMISTRY LA English DT Article DE copper; methylimidazole; imidazole; structure; synthesis ID CHROMOPHORES AB Treatment of copper(II) sulfate with four equivalents of N-methylimidazole in dry methanol leads to isolation of tetrakis-N-methylimidazole copper(II) sulfate, [Cu(NMeim)4](SO4). X-ray quality crystals of the complex were isolated by evaporation. The complex crystallizes in the Pi (No. 2) space group with a = 9.0754(6) Angstrom, b=9.9729(7)Angstrom, c=12.745(2)Angstrom, alpha=98.342(9)degrees, beta=95.367(9)degrees, gamma=114.153(5)degrees, Z=2, V(Angstrom(3))=1026.3(4), R = 0.031 and R-w = 0.038. C1 Cleveland State Univ, Dept Chem, Cleveland, OH 44115 USA. Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Hepp, AF (reprint author), Cleveland State Univ, Dept Chem, Cleveland, OH 44115 USA. NR 14 TC 0 Z9 0 U1 3 U2 5 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0095-8972 J9 J COORD CHEM JI J. Coord. Chem. PD MAY 20 PY 2003 VL 56 IS 8 BP 647 EP 653 DI 10.1080/0095897031000069058 PG 7 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 703PZ UT WOS:000184291300001 ER PT J AU Huang, C Zhang, QM Su, J AF Huang, C Zhang, QM Su, J TI High-dielectric-constant all-polymer percolative composites SO APPLIED PHYSICS LETTERS LA English DT Article ID POLY(VINYLIDENE FLUORIDE-TRIFLUOROETHYLENE) COPOLYMER; ELECTROMECHANICAL RESPONSE; ELECTRORHEOLOGICAL FLUIDS; ELECTROSTRICTION; CONDUCTIVITY; POLYANILINE; ELASTOMERS; TERPOLYMER; ACTUATORS; BEHAVIOR AB We report here an all-polymer high-dielectric (dielectric constant K>1000 at 1 kHz) percolative composite material, fabricated by a combination of conductive polyaniline particles (K>10(5)) within a poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) terpolymer matrix (K>50). These high-K polymer hybrid materials also exhibit high electromechanical responses. For example, 1.5% strain, which is proportional to the square of the field applied, can be induced by a field of 9.5 MV/m, an eightfold reduction in field applied compared with that in a fluoroterpolymer matrix. (C) 2003 American Institute of Physics. C1 Penn State Univ, Dept Elect Engn, University Pk, PA 16802 USA. Penn State Univ, Mat Res Inst, University Pk, PA 16802 USA. NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. RP Zhang, QM (reprint author), Penn State Univ, Dept Elect Engn, University Pk, PA 16802 USA. NR 25 TC 148 Z9 153 U1 9 U2 59 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 19 PY 2003 VL 82 IS 20 BP 3502 EP 3504 DI 10.1063/1.1575505 PG 3 WC Physics, Applied SC Physics GA 677TH UT WOS:000182823300042 ER PT J AU Takegawa, N Kondo, Y Ko, M Koike, M Kita, K Blake, DR Hu, W Scott, C Kawakami, S Miyazaki, Y Russell-Smith, J Ogawa, T AF Takegawa, N Kondo, Y Ko, M Koike, M Kita, K Blake, DR Hu, W Scott, C Kawakami, S Miyazaki, Y Russell-Smith, J Ogawa, T TI Photochemical production of O-3 in biomass burning plumes in the boundary layer over northern Australia SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TROPOSPHERIC OZONE; ATLANTIC AB [1] In situ aircraft measurements of ozone (O-3) and its precursors were made over northern Australia in August September 1999 during the Biomass Burning and Lightning Experiment Phase B (BIBLE-B). A clear positive correlation of O3 with carbon monoxide ( CO) was found in biomass burning plumes in the boundary layer (<3 km). The Delta O-3/Delta CO ratio ( linear regression slope of O-3-CO correlation) is found to be 0.12 ppbv/ppbv, which is comparable to the ratio of 0.15 ppbv/ppbv observed at 0 4 km over the Amazon and Africa in previous studies. The net flux of O-3 exported from northern Australia during BIBLE-B is estimated to be 0.3 Gmol O-3/day. In the biomass burning region, large enhancements of O-3 were coincident with the locations of biomass burning hot spots, suggesting that major O-3 production occurred near fires ( horizontal scale < 50 km). C1 Univ Tokyo, Adv Sci & Technol Res Ctr, Meguro Ku, Tokyo 1538904, Japan. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Tokyo, Grad Sch Sci, Dept Earth & Planetary Sci, Bunkyo Ku, Tokyo 1130033, Japan. Ibaraki Univ, Grad Sch Sci, Dept Environm Sci, Ibaraki 3108512, Japan. Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. Dept Environm Qual, Richmond, VA 23219 USA. Atmospher & Environm Res Inc, Lexington, MA 02421 USA. Natl Space Dev Agcy Japan, Earth Observat Res Ctr, Tokyo, Japan. Bushfire Council No Terr, Darwin, NT, Australia. RP Takegawa, N (reprint author), Univ Tokyo, Adv Sci & Technol Res Ctr, Meguro Ku, 4-6-1 Komaba, Tokyo 1538904, Japan. EM takegawa@atmos.rcast.u-tokyo.ac.jp RI Koike, Makoto/F-4366-2011; Kondo, Yutaka/D-1459-2012; Miyazaki, Yuzo/C-6920-2010; Ko, Malcolm/D-5898-2015 NR 18 TC 15 Z9 15 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 17 PY 2003 VL 30 IS 10 AR 1500 DI 10.1029/2003GL017017 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 682QJ UT WOS:000183102800001 ER PT J AU Greeley, R Balme, MR Iversen, JD Metzger, S Mickelson, R Phoreman, J White, B AF Greeley, R Balme, MR Iversen, JD Metzger, S Mickelson, R Phoreman, J White, B TI Martian dust devils: Laboratory simulations of particle threshold SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID MARS ORBITER CAMERA; GLOBAL SURVEYOR; SALTATION THRESHOLD; PATHFINDER MISSION; WINDBLOWN DUST; LANDING SITE; ATMOSPHERE; SURFACE; FEATURES; VORTICES AB [1] An apparatus has been fabricated to simulate terrestrial and Martian dust devils. Comparisons of surface pressure profiles through the vortex core generated in the apparatus with both those in natural dust devils on Earth and those inferred for Mars are similar and are consistent with theoretical Rankine vortex models. Experiments to determine particle threshold under Earth ambient atmospheric pressures show that sand (particles > 60 mum in diameter) threshold is analogous to normal boundary-layer shear, in which the rotating winds of the vortex generate surface shear and hence lift. Lowerpressure experiments down to -65 mbar follow this trend for sand-sized particles. However, smaller particles (i. e., dust) and all particles at very low pressures (-10-60 mbar) appear to be subjected to an additional lift function interpreted to result from the strong decrease in atmospheric pressure centered beneath the vortex core. Initial results suggest that the wind speeds required for the entrainment of grains -2 mum in diameter (i. e., Martian dust sizes) are about half those required for entrainment by boundary layer winds on both Earth and Mars. C1 Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. Iowa State Univ, Dept Aerosp Engn & Engn Mech, Iowa City, IA 50011 USA. Univ Nevada, Dept Geol Sci, Reno, NV 89557 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Davis, Dept Mech & Aerosp Engn, Davis, CA 95616 USA. RP Greeley, R (reprint author), Arizona State Univ, Dept Geol Sci, Box 871404, Tempe, AZ 85287 USA. NR 77 TC 81 Z9 82 U1 2 U2 11 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 17 PY 2003 VL 108 IS E5 AR 5041 DI 10.1029/2002JE001987 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 682TA UT WOS:000183107400002 ER PT J AU Sanchez, BV Rowlands, DD Haberle, RM Schaeffer, J AF Sanchez, BV Rowlands, DD Haberle, RM Schaeffer, J TI Atmospheric rotational effects on Mars based on the NASA Ames general circulation model SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID MARTIAN ATMOSPHERE; GRAVITY-FIELD AB [1] Atmospheric rotational effects on Mars are computed and analyzed. Both axial (DeltaLOD) and equatorial effects (polar motion) are evaluated. Surface values of stress and pressure from the NASA Ames general circulation model are used as inputs to compute the topographic, stress, and gravitational torques. Time series for the ice caps moments of inertia and the axial component of atmospheric angular momentum provide inputs for a separate computation of axial effects. Stress torque dominates the torque budget. This is different from the results obtained from Earth atmospheric models, in which pressure effects are paramount. Axial torque and ice caps yield annual and semiannual DeltaLOD amplitudes of 0.747 and 0.121 ms, respectively. Torque-induced polar motion reaches a maximum of 16.26 mm in the second half of the Martian northern hemisphere winter. Changes in LOD using the angular momentum approach are 0.187 and 0.136 ms for the annual and semiannual harmonics. The expected precision of the planned NetLander Ionospheric and Geodesic Experiment (NEIGE) should detect the main harmonics in the DeltaLOD time series. Annual and semiannual polar motion harmonics induced by atmospheric torque are below the level of NEIGE detectability. C1 NASA, Space Geodesy Branch, Terr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Div Space Sci, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Sanchez, BV (reprint author), NASA, Space Geodesy Branch, Terr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Sanchez, Braulio/I-5952-2013; Rowlands, David/D-2751-2012 NR 20 TC 9 Z9 9 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 17 PY 2003 VL 108 IS E5 AR 5040 DI 10.1029/2002JE001984 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 682TA UT WOS:000183107400001 ER PT J AU Kelton, KF Lee, GW Gangopadhyay, AK Hyers, RW Rathz, TJ Rogers, JR Robinson, MB Robinson, DS AF Kelton, KF Lee, GW Gangopadhyay, AK Hyers, RW Rathz, TJ Rogers, JR Robinson, MB Robinson, DS TI First x-ray scattering studies on electrostatically levitated metallic liquids: Demonstrated influence of local icosahedral order on the nucleation barrier SO PHYSICAL REVIEW LETTERS LA English DT Article ID CRYSTAL-FORMING ALLOYS; SHORT-RANGE ORDER; ORIENTATIONAL ORDER; MELTS; SOLIDIFICATION; SYMMETRY; GLASSES AB To explain the unusual stability of undercooled liquids against crystallization, Frank hypothesized that the local structures of undercooled liquids contain a significant degree of icosahedral short-range order, which is incompatible with long-range periodicity. We present here the first direct experimental demonstration of Frank's complete hypothesis, showing a correlation between the nucleation barrier and a growing icosahedral short-range order with decreasing temperature in a Ti39.5Zr39.5Ni21 liquid. A new experimental facility, BESL (Beamline Electrostatic Levitation), was developed to enable the synchrotron x-ray structural studies on deeply undercooled, reactive liquids. C1 Washington Univ, Dept Phys, St Louis, MO 63130 USA. Univ Massachusetts, Amherst, MA 01003 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. US DOE, Ames Lab, Ames, IA 50011 USA. RP Kelton, KF (reprint author), Washington Univ, Dept Phys, St Louis, MO 63130 USA. RI Hyers, Robert/G-3755-2010 NR 22 TC 336 Z9 343 U1 8 U2 68 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 16 PY 2003 VL 90 IS 19 AR 195504 DI 10.1103/PhysRevLett.90.195504 PG 4 WC Physics, Multidisciplinary SC Physics GA 679NG UT WOS:000182928300024 PM 12785956 ER PT J AU Bolen, SM Chandrasekar, V AF Bolen, SM Chandrasekar, V TI Quantitative estimation of Tropical Rainfall Mapping Mission precipitation radar signals from ground-based polarimetric radar observations SO RADIO SCIENCE LA English DT Article DE TRMM; precipitation; polarimetric; radar; attenuation ID SIZE DISTRIBUTION; SHAPE; SPECTRA AB The Tropical Rainfall Mapping Mission (TRMM) is the first mission dedicated to measuring rainfall from space using radar. The precipitation radar ( PR) is one of several instruments aboard the TRMM satellite that is operating in a nearly circular orbit with nominal altitude of 350 km, inclination of 35degrees, and period of 91.5 min. The PR is a single-frequency K-u-band instrument that is designed to yield information about the vertical storm structure so as to gain insight into the intensity and distribution of rainfall. Attenuation effects on PR measurements, however, can be significant and as high as 10-15 dB. This can seriously impair the accuracy of rain rate retrieval algorithms derived from PR signal returns. Quantitative estimation of PR attenuation is made along the PR beam via ground-based polarimetric observations to validate attenuation correction procedures used by the PR. The reflectivity (Z(h)) at horizontal polarization and specific differential phase (K-dp) are found along the beam from S-band ground radar measurements, and theoretical modeling is used to determine the expected specific attenuation (k) along the space-Earth path at K-u-band frequency from these measurements. A theoretical k-K-dp relationship is determined for rain when K(dp)greater than or equal to0.5degrees/km, and a power law relationship, k=a Z(h)(b), is determined for light rain and other types of hydrometers encountered along the path. After alignment and resolution volume matching is made between ground and PR measurements, the two-way path-integrated attenuation ( PIA) is calculated along the PR propagation path by integrating the specific attenuation along the path. The PR reflectivity derived after removing the PIA is also compared against ground radar observations. C1 NASA, Lyndon B Johnson Space Ctr, Avion Syst Div, Houston, TX 77056 USA. Colorado State Univ, Ft Collins, CO 80525 USA. RP Bolen, SM (reprint author), NASA, Lyndon B Johnson Space Ctr, Avion Syst Div, Houston, TX 77056 USA. EM sbolen@ems.jsc.nasa.gov; chandra@engr.colostate.edu NR 27 TC 5 Z9 5 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 EI 1944-799X J9 RADIO SCI JI Radio Sci. PD MAY 16 PY 2003 VL 38 IS 3 AR 8056 DI 10.1029/2002RS002625 PG 12 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 682UC UT WOS:000183109900001 ER PT J AU Bennett, VC Horan, MF Brandon, AD Neal, CR AF Bennett, VC Horan, MF Brandon, AD Neal, CR TI Highly siderophile elements in the Earth and meteorites: A volume in honor of John Morgan SO CHEMICAL GEOLOGY LA English DT Editorial Material ID UPPER-MANTLE; OSMIUM; SYSTEMATICS; RHENIUM C1 Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT, Australia. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Notre Dame, Dept Civil Engn & Geol Sci, Notre Dame, IN 46556 USA. RP Bennett, VC (reprint author), Australian Natl Univ, Res Sch Earth Sci, GPO Box 4, Canberra, ACT, Australia. NR 17 TC 1 Z9 1 U1 0 U2 0 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 15 PY 2003 VL 196 IS 1-4 BP 1 EP 3 DI 10.1016/S0009-2541(02)00403-5 PG 3 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 671HA UT WOS:000182458200001 ER PT J AU Jones, JH Neal, CR Ely, JC AF Jones, JH Neal, CR Ely, JC TI Signatures of the highly siderophile elements in the SNC meteorites and Mars: a review and petrologic synthesis SO CHEMICAL GEOLOGY LA English DT Article DE SNC meteorites; siderophile elements; Os isotopes; core formation; mars geochemistry ID PLATINUM-GROUP ELEMENTS; PLASMA-MASS SPECTROMETRY; SHERGOTTITE PARENT BODY; RE-OS ISOTOPE; MARTIAN METEORITES; EARLY DIFFERENTIATION; CORE FORMATION; UPPER-MANTLE; RB-SR; FRACTIONATION AB We have evaluated the highly siderophile element (HSE) signatures of the martian (SNC) meteorites using new and literature data. These Ir and Os concentrations correlate with the Mg# [molar Mg/(Mg + Fe)], Cr and Ni, suggesting that olivine or chromite acts as a host for compatible siderophiles. Our analysis agrees with others who have suggested that the martian mantle has chondritic relative abundances of siderophiles. We also agree that, unlike the Sr and Nd isotopic systems, there is no evidence from Os isotopes for crustal assimilation. Comparisons of the siderophile element ratios of ALH 84001 to younger SNCs give no indication of a change in the martian siderophile element pattern over time. (C) 2002 Published by Elsevier Science B.V. C1 NASA, JSC, Houston, TX 77058 USA. Univ Notre Dame, Dept Civil Engn & Geol Sci, Notre Dame, IN 46556 USA. RP Jones, JH (reprint author), NASA, JSC, Mail Code SR, Houston, TX 77058 USA. NR 57 TC 27 Z9 27 U1 0 U2 4 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 15 PY 2003 VL 196 IS 1-4 BP 21 EP 41 DI 10.1016/S0009-2541(02)00404-7 PG 21 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 671HA UT WOS:000182458200003 ER PT J AU Hash, D Bose, D Govindan, TR Meyyappan, M AF Hash, D Bose, D Govindan, TR Meyyappan, M TI Simulation of the dc plasma in carbon nanotube growth SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; ASSISTED DIAMOND GROWTH; GLASS SUBSTRATE; COUPLED PLASMA; GRAPHITIC NANOFIBERS; PATTERNED GROWTH; CONTINUUM MODEL; LOW-TEMPERATURE; HIPCO PROCESS; GAS-MIXTURES AB A model for the dc plasma used in carbon nanotube growth is presented, and one-dimensional simulations of an acetylene/ammonia/argon system are performed. The effect of dc bias is illustrated by examining electron temperature, electron and ion densities, and neutral densities. Introducing a tungsten filament in the dc plasma, as in hot filament chemical vapor deposition with plasma assistance, shows negligible influence on the system characteristics. (C) 2003 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Eloret Corp, Moffett Field, CA USA. RP Hash, D (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 65 TC 50 Z9 53 U1 3 U2 8 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 2003 VL 93 IS 10 BP 6284 EP 6290 DI 10.1063/1.1568155 PN 1 PG 7 WC Physics, Applied SC Physics GA 677CQ UT WOS:000182789700067 ER PT J AU Ruzmaikin, A Lawrence, J Cadavid, C AF Ruzmaikin, A Lawrence, J Cadavid, C TI A simple model of stratospheric dynamics including solar variability SO JOURNAL OF CLIMATE LA English DT Article ID INTERANNUAL VARIABILITY; NORTHERN-HEMISPHERE; ARCTIC OSCILLATION; VACILLATION MODEL; CIRCULATION; CLIMATE AB A simple dynamic model, truncated from the stratospheric wave - zonal flow interaction Holton and Mass model, is introduced and studied. This model consists of three ordinary differential equations controlled by two parameters: the initial amplitude of planetary waves and the vertical gradient of the zonal wind. The changes associated with seasonal variations and with the solar variability are introduced as periodic modulations of the zonal wind gradient. The major climatic response to these changes is seen through modulation of the number of cold and warm winters. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Calif State Univ Northridge, Dept Phys & Astron, Northridge, CA 91330 USA. RP Ruzmaikin, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 28 TC 11 Z9 11 U1 0 U2 0 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 15 PY 2003 VL 16 IS 10 BP 1593 EP 1600 DI 10.1175/1520-0442-16.10.1593 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 675MQ UT WOS:000182699500013 ER PT J AU Wilson, DJ Western, AW Grayson, RB Berg, AA Lear, MS Rodell, M Famiglietti, JS Woods, RA McMahon, TA AF Wilson, DJ Western, AW Grayson, RB Berg, AA Lear, MS Rodell, M Famiglietti, JS Woods, RA McMahon, TA TI Spatial distribution of soil moisture over 6 and 30 cm depth, Mahurangi river catchment, New Zealand SO JOURNAL OF HYDROLOGY LA English DT Article DE soil moisture; spatial patterns; correlation ID WATER-CONTENT; PROFILE RETRIEVAL; ASSIMILATION; PATTERNS; VARIABILITY; TARRAWARRA; SCALE AB Ground-based measurement of the spatial distribution of soil moisture can be difficult because sampling is essentially made at a point and the choice of both sample depth and sample spacing affects the interpretation of the measurements. Hydrological interest has generally been in soil moisture of the root zone. Microwave Remote Sensing methods are now available that allow the interpretation of spatial distributions of soil moisture, however, their signals respond to moisture in the upper few centimetres of soil. These instruments are still being developed, but one of the questions surrounding their application is how to interpret the surface moisture in a hydrological context. In this study we compare measurements of soil moisture in 0-30 cm of soil with those in 0-6 cm to examine how representative this surface measure is with regard to the root zone. Detailed spatial measurements of soil moisture were conducted at three pasture sites in the 50 km(2) Mahurangi River catchment of northern New Zealand as part of a comprehensive hydrology project; MARVEX (MAhurangi River Variability EXperiment). In three field sites, on each of three occasions, field measurements were made using both 30 and 6 cm dielectric-based instruments. Spatial grids of several hundred moisture measurements were collected over 0-30 cm and compared with those collected simultaneously over 0-6 cm. Results indicate that temporal and spatial issues interfere with correlation of the two sets of series. Rapid wetting of 0-6 cm compared with 0-30 cm is seen following storm activity. Some evidence of the decoupling of moisture content response is also evident when sites are measured on days following a storm. Rapid, but not unrealistic, response to intense rainfall was also observed. Implications are that detailed and accurate knowledge of local soil conditions and a sound model of soil water redistribution are required before surface soil moisture measurements can be used to infer root zone behaviour. Such knowledge was not available in this study, from either published data or field observation. In this study, without suitable a priori knowledge, soil property information was found via calibration. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Univ Melbourne, Ctr Environm Appl Hydrol, Melbourne, Vic 3010, Australia. Univ Melbourne, Cooperat Res Ctr Catchment Hydrol, Dept Civil & Environm Engn, Melbourne, Vic 3010, Australia. Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA. Univ Texas, Dept Geol Sci, Austin, TX 78712 USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. NIWA Res, Christchurch 8004, New Zealand. RP Wilson, DJ (reprint author), Univ Melbourne, Ctr Environm Appl Hydrol, Melbourne, Vic 3010, Australia. RI Western, Andrew/G-1730-2011; Rodell, Matthew/E-4946-2012; Woods, Ross/C-6696-2013 OI Western, Andrew/0000-0003-4982-146X; Rodell, Matthew/0000-0003-0106-7437; Woods, Ross/0000-0002-5732-5979 NR 34 TC 58 Z9 63 U1 7 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD MAY 15 PY 2003 VL 276 IS 1-4 BP 254 EP 274 DI 10.1016/S0022-1694(03)00060-X PG 21 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA 689BF UT WOS:000183471200018 ER PT J AU Ling, PD Lednicky, JA Keitel, WA Poston, DG White, ZS Peng, RS Liu, ZS Mehta, SK Pierson, DL Rooney, CM Vilchez, RA Smith, EO Butel, JS AF Ling, PD Lednicky, JA Keitel, WA Poston, DG White, ZS Peng, RS Liu, ZS Mehta, SK Pierson, DL Rooney, CM Vilchez, RA Smith, EO Butel, JS TI The dynamics of herpesvirus and polyomavirus reactivation and shedding in healthy adults: A 14-month longitudinal study SO JOURNAL OF INFECTIOUS DISEASES LA English DT Article ID EPSTEIN-BARR-VIRUS; PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY; PERIPHERAL-BLOOD LEUKOCYTES; REAL-TIME PCR; JC-VIRUS; BK-VIRUS; IMMUNOCOMPETENT INDIVIDUALS; TRANSPLANT RECIPIENTS; REGULATORY REGIONS; COMPLETE GENOMES AB Humans are infected with viruses that establish long-term persistent infections. To address whether immunocompetent individuals control virus reactivation globally or independently and to identify patterns of sporadic reactivation, we monitored herpesviruses and polyomaviruses in 30 adults, over 14 months. Epstein-Barr virus ( EBV) DNA was quantitated in saliva and peripheral blood mononuclear cells (PBMCs), cytomegalovirus (CMV) was assayed in urine, and JC virus (JCV) and BK virus (BKV) DNAs were assayed in urine and PBMCs. All individuals shed EBV in saliva, whereas 67% had greater than or equal to1 blood sample positive for EBV. Levels of EBV varied widely. CMV shedding occurred infrequently but occurred more commonly in younger individuals (P < .03). JCV and BKV virurias were 46.7% and 0%, respectively. JCV shedding was age dependent and occurred commonly in individuals >= 40 years old (P < .03). Seasonal variation was observed in shedding of EBV and JCV, but there was no correlation among shedding of EBV, CMV, and JCV (P > .50). Thus, adults independently control persistent viruses, which display discordant, sporadic reactivations. C1 Baylor Coll Med, Dept Mol Virol & Microbiol, Houston, TX 77030 USA. Baylor Coll Med, Dept Med, Houston, TX 77030 USA. Baylor Coll Med, Dept Pediat, Houston, TX 77030 USA. Baylor Coll Med, Ctr Cell & Gene Therapy, Houston, TX 77030 USA. Enterprise Advisory Serv Inc, Houston, TX USA. NASA, Life Sci Res Labs, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Baylor Coll Med, Dept Mol Virol & Microbiol, Mail Stop BCM-385,1 Baylor Plaza, Houston, TX 77030 USA. EM jbutel@bcm.tmc.edu NR 56 TC 95 Z9 100 U1 1 U2 2 PU OXFORD UNIV PRESS INC PI CARY PA JOURNALS DEPT, 2001 EVANS RD, CARY, NC 27513 USA SN 0022-1899 EI 1537-6613 J9 J INFECT DIS JI J. Infect. Dis. PD MAY 15 PY 2003 VL 187 IS 10 BP 1571 EP 1580 DI 10.1086/374739 PG 10 WC Immunology; Infectious Diseases; Microbiology SC Immunology; Infectious Diseases; Microbiology GA 673HA UT WOS:000182573600008 PM 12721937 ER PT J AU Halasinski, TM Weisman, JL Ruiterkamp, R Lee, TJ Salama, F Head-Gordon, M AF Halasinski, TM Weisman, JL Ruiterkamp, R Lee, TJ Salama, F Head-Gordon, M TI Electronic absorption spectra of neutral perylene (C20H12), terrylene (C30H16), and quaterrylene (C40H20) and their positive and negative ions: Ne matrix-isolation spectroscopy and time-dependent density functional theory calculations SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID POLYCYCLIC AROMATIC HYDROCARBON; DIFFUSE INTERSTELLAR BANDS; CATIONS; AR; APPROXIMATION; FLUORESCENCE; NAPHTHALENE AB We present an experimental and theoretical study of an interesting series of polycyclic aromatic hydrocarbons, the oligorylenes. The absorption spectra of perylene, terrylene, and quaterrylene in neutral, cationic, and anionic charge states are obtained by matrix-isolation spectroscopy in Ne. The experimental spectra are dominated by a bright state that red shifts with growing molecular size. Excitation energies and state symmetry assignments for this state are obtained by calculations using time-dependent density functional theory methods. These calculations also provide additional information and insight into the trends in oscillator strength and excitation energy for the bright states: in particular, the oscillator strength per unit mass of carbon increases along the series. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Leiden Observ, Raymond & Beverly Sackler Lab, NL-2300 RA Leiden, Netherlands. NASA, Ames Res Ctr, Adv Supercomp Div, Moffett Field, CA 94035 USA. RP Salama, F (reprint author), NASA, Ames Res Ctr, Div Space Sci, Mail Stop 245-6, Moffett Field, CA 94035 USA. RI Lee, Timothy/K-2838-2012; Salama, Farid/A-8787-2009 OI Salama, Farid/0000-0002-6064-4401 NR 26 TC 102 Z9 103 U1 1 U2 33 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 15 PY 2003 VL 107 IS 19 BP 3660 EP 3669 DI 10.1021/jp027394w PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 678YH UT WOS:000182893900011 ER PT J AU Cardelino, BH Moore, CE Cardelino, CA McCall, SD Frazier, DO Bachmann, KJ AF Cardelino, BH Moore, CE Cardelino, CA McCall, SD Frazier, DO Bachmann, KJ TI Semiclassical calculation of reaction rate constants for homolytical dissociation reactions of interest in organometallic vapor-phase epitaxy (OMVPE) SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID METHYL RADICAL RECOMBINATION; HIGH-PRESSURE RANGE; TRANSITION-STATES; DECOMPOSITION; PYROLYSIS; TRIMETHYLINDIUM; DEPOSITION; LOOSENESS; ENERGIES; GALLIUM AB A procedure for calculating homolytic dissociation rate constants is reported for modeling organometallic vapor-phase epitaxy (OMVPE) of III-V compounds for all pressure regimes. Reaction rate constants were predicted following a semiclassical approach based on quantum mechanical calculations and transition-state theory. The critical configuration was determined using linear interpolations for the geometry of the intermediate structures, Morse potentials for the intermediate electronic energies, and Hase's relationship for the vibrational frequencies that become annihilated. Low-pressure rate constants were calculated from Rice-Ramsperger-Kassel-Marcus (RRKM) theory following the Troe approach. The calculations were compared with experimental values for the dissociation of one methyl radical from the closed-shell molecules Al(CH3)(3), Ga(CH3)(3), and In(CH3)(3) and the radical molecules Ga(CH3)(2) and In(CH3) and for the dissociation of one hydrogen atom from NH3, PH3, and AsH3. A simplified system of reactions for the homolytic dissociation of In(CH3)(3) was modeled in an OMV reactor designed for the pressure range 10(-2) to 10(2) atm using computational fluid dynamics coupled with chemical kinetics. The steady-state simulations were carried out at 1000 K and at N-2 pressures of 1 and 20 atm. C1 Spelman Coll, Dept Chem, Atlanta, GA 30314 USA. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA. RP Spelman Coll, Dept Chem, Box 238, Atlanta, GA 30314 USA. EM cardelino@spelman.edu NR 42 TC 13 Z9 13 U1 2 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 15 PY 2003 VL 107 IS 19 BP 3708 EP 3718 DI 10.1021/jp026289j PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 678YH UT WOS:000182893900018 ER PT J AU Giver, LP Brown, LR Chackerian, C Freedman, RS AF Giver, LP Brown, LR Chackerian, C Freedman, RS TI The rovibrational intensities of five absorption bands of (CO2)-C-12-O-16 between 5218 and 5349 cm(-)1 SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE carbon dioxide; absorption bands; intensities; near IR ID DIRECT NUMERICAL DIAGONALIZATION; ENERGY-LEVELS; CARBON-DIOXIDE; CO2; FREQUENCY; DATABASE; EDITION; REGION AB Absolute line intensities, band intensities, and Herman-Wallis parameters were measured for the (01(1)2)(I)<--(00(0)0) perpendicular band of (CO2)-C-12-O-16 centered at 5315 cm(-1), along with the three nearby associated hot bands: (10(0)2)(II)<-- (01(1)0)(I) at 5248 cm(-1), (02(2)2)(I)<--(01(1)0)(I) at 5291 cm(-1), and (10(0)2)(I)<--(01(1)0)(I) at 5349 cm(-1). The nearby parallel hot band (30(0)1)(I)<--(10(0)0)(II) at 5218 cm(-1) was also included in this study. The rotationless band intensities at 296 K are, respectively, [GRAPHICS] (C) 2003 Elsevier Science Ltd. All rights reserved. C1 NASA, Ames Res Ctr, Atmospher Res Branch, Moffett Field, CA 94035 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. SETI Inst, Mountain View, CA 94043 USA. Space Phys Res Inst, Sunnyvale, CA 94087 USA. RP Giver, LP (reprint author), NASA, Ames Res Ctr, Atmospher Res Branch, N 245-4, Moffett Field, CA 94035 USA. EM lgiver@mail.arc.nasa.gov NR 19 TC 11 Z9 12 U1 0 U2 3 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 2003 VL 78 IS 3-4 BP 417 EP 436 AR PII S0022-4073(02)00277-7 DI 10.1016/S0022-4073(02)00277-7 PG 20 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 658JZ UT WOS:000181719000012 ER PT J AU Wang, MH AF Wang, MH TI An efficient method for multiple radiative transfer computations and the lookup table generation SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article AB An efficient method for the multiple radiative-transfer computations is proposed. The method is based on the fact that, in the radiative-transfer computation, most of the CPU time is used in the numerical integration for the Fourier components of the scattering phase function. With the new method, the lookup tables, which are usually needed to convert the spaceborne and the airborne sensor-measured signals to the desired physical and optical quantities, can be generated efficiently. We use the ocean color remote sensor Sea-viewing Wide Field-of-view Sensor as an example to show that, with the new approach, the CPU time can be reduced significantly for the generation of the lookup tables. The new scheme is useful and effective for the multiple radiative-transfer computations. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Univ Maryland Baltimore Cty, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wang, MH (reprint author), Univ Maryland Baltimore Cty, NASA, Goddard Space Flight Ctr, Code 970-2, Greenbelt, MD 20771 USA. EM wang@simbios.gsfc.nasa.gov RI Wang, Menghua/F-5631-2010 OI Wang, Menghua/0000-0001-7019-3125 NR 7 TC 9 Z9 9 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD MAY 15 PY 2003 VL 78 IS 3-4 BP 471 EP 480 AR PII S0022-4073(02)00278-9 DI 10.1016/S0022-4073(02)00278-9 PG 10 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 658JZ UT WOS:000181719000016 ER PT J AU Poyneer, LA Troy, M Macintosh, B Gavel, DT AF Poyneer, LA Troy, M Macintosh, B Gavel, DT TI Experimental validation of Fourier-transform wave-front reconstruction at the Palomar Observatory SO OPTICS LETTERS LA English DT Article AB Wave-front reconstruction with use of the Fourier transform has been validated through theory and simulation. This method provides a dramatic reduction in computational costs for large adaptive (AO) systems. Because such a reconstructor can be expressed as a matrix, it can be used as an alternative in a matrix-based AO control system. This was done with the Palomar Observatory AO system on the 200-in. Hale telescope. Results of these tests indicate that Fourier-transform wave-front, reconstruction works in a real system. For both bright and dim stars, a Hudgin-geometry Fourier-transform method produced performance comparable to that of the Palomar Adaptive Optics least squares. The Fried-geometry method had a noticeable Strehl ratio performance degradation of 0.043 in the K band (165-nm rms wave-front error added in quadrature) on a dim star. (C) 2003 Optical Society of America. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Poyneer, LA (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Tippie, Abbie/A-1106-2007 NR 7 TC 21 Z9 21 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD MAY 15 PY 2003 VL 28 IS 10 BP 798 EP 800 DI 10.1364/OL.28.000798 PG 3 WC Optics SC Optics GA 674JW UT WOS:000182634500012 PM 12779150 ER PT J AU Buonanno, A Chen, YB Vallisneri, M AF Buonanno, A Chen, YB Vallisneri, M TI Detecting gravitational waves from precessing binaries of spinning compact objects: Adiabatic limit SO PHYSICAL REVIEW D LA English DT Article ID POST-NEWTONIAN ORDER; BLACK-HOLE COALESCENCES; COALESCING BINARIES; 2ND-POST-NEWTONIAN ORDER; LASER-INTERFEROMETER; INSPIRALING BINARIES; SEARCH TEMPLATES; ENERGY-LOSS; RADIATION; SYSTEMS AB Black-hole (BH) binaries with single-BH masses m=(5-20)M, moving on quasicircular orbits, are among the most promising sources for first-generation ground-based gravitational-wave (GW) detectors. Until now, the development of data-analysis techniques to detect GWs from these sources has been focused mostly on nonspinning BHs. The data-analysis problem for the spinning case is complicated by the necessity to model the precession-induced modulations of the GW signal, and by the large number of parameters needed to characterize the system, including the initial directions of the spins, and the position and orientation of the binary with respect to the GW detector. In this paper we consider binaries of maximally spinning BHs, and we work in the adiabatic-inspiral regime to build families of modulated detection templates that (i) are functions of very few physical and phenomenological parameters, (ii) model remarkably well the dynamical and precessional effects on the GW signal, with fitting factors on average greater than or similar to0.97, (iii) but, however, might require increasing the detection thresholds, offsetting at least partially the gains in the fitting factors. Our detection-template families are quite promising also for the case of neutron-star-black-hole binaries, with fitting factors on average approximate to0.93. For these binaries we also suggest (but do not test) a further template family, which would produce essentially exact waveforms written directly in terms of the physical spin parameters. C1 Inst Astrophys Paris, GReCO, FRE 2435, CNRS, F-75014 Paris, France. CALTECH, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Inst Astrophys Paris, GReCO, FRE 2435, CNRS, 98bis Blvd Arago, F-75014 Paris, France. RI Chen, Yanbei/A-2604-2013 NR 64 TC 205 Z9 204 U1 0 U2 2 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 15 PY 2003 VL 67 IS 10 AR 104025 DI 10.1103/PhysRevD.67.104025 PG 31 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 687LB UT WOS:000183377200068 ER PT J AU Phillips, NG Hu, BL AF Phillips, NG Hu, BL TI Noise kernel and the stress energy bitensor of quantum fields in hot flat space and the Schwarzschild black hole under the Gaussian approximation SO PHYSICAL REVIEW D LA English DT Article ID EINSTEIN-LANGEVIN EQUATION; QUANTIZED SCALAR FIELDS; EARLY UNIVERSE; SEMICLASSICAL GRAVITY; BACK-REACTION; STOCHASTIC SPACETIMES; HORIZON FLUCTUATIONS; GRAVITATIONAL-FIELD; PARTICLE-PRODUCTION; CURVED SPACETIME AB We continue our investigation of the properties of the noise kernel in curved spacetimes [N. G. Phillips and B. L. Hu, Phys. Rev. D 63, 104001 (2001)] by working out explicit examples by means of the modified point-separation scheme and the Gaussian approximation for the Green functions in the manner of Bekenstein, Parker, and Page [J. D. Bekenstein and L. Parker, Phys. Rev. D 23, 2850 (1981); D. N. Page, ibid. 25, 1499 (1982)]. In the first part we consider the class of optical spacetimes. As a first example we derive the regularized noise kernel for a thermal field in flat space. It is useful for black hole nucleation considerations. In the second example of an optical-Schwarzschild spacetime we obtain after this procedure a finite expression for the noise kernel at the horizon. In the second part we consider the noise kernel for a scalar field in the Schwarzschild black hole. Knowledge of the noise kernel is essential for studying issues related to black hole horizon fluctuations and Hawking radiation back reaction. Much of the work in this part is to determine how the divergent piece conformally transforms under the point-separation scheme. For the Schwarzschild metric we find that the fluctuations of the stress tensor of the Hawking flux in the far field region checks with the analytic results given by Campos and Hu earlier [A. Campos and B. L. Hu, Phys. Rev. D 58, 125021 (1998); Int. J. Theor. Phys. 38, 1253 (1999)]. We also verify Page's result for the stress tensor, which, though used often, still lacks a rigorous proof, since in his original work the direct use of the conformal transformation was circumvented. We find that the noise kernel at the Schwarzschild horizon is finite. This dispels speculations in some recent papers that the black hole fluctuations diverge at the horizon. However, as already manifest in the optical case, the Gaussian approximated Green function which works surprisingly well for the stress tensor at the Schwarzschild horizon produces significant error in the noise kernel evaluated there. We check this using the trace anomaly expression and identify the failure as occurring at the fourth covariant derivative order. C1 NASA, SSAI, Astron & Solar Phys Lab, GSFC, Greenbelt, MD 20771 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. RP NASA, SSAI, Astron & Solar Phys Lab, GSFC, Code 685, Greenbelt, MD 20771 USA. EM Nicholas.G.Phillips@gsfc.nasa.gov; hub@physics.umd.edu NR 83 TC 17 Z9 17 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 15 PY 2003 VL 67 IS 10 AR 104002 DI 10.1103/PhysRevD.67.104002 PG 26 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 687LB UT WOS:000183377200045 ER PT J AU Burrage, DM Heron, ML Hacker, JM Miller, JL Stieglitz, TC Steinberg, CR Prytz, A AF Burrage, DM Heron, ML Hacker, JM Miller, JL Stieglitz, TC Steinberg, CR Prytz, A TI Structure and influence of tropical river plumes in the Great Barrier Reef: application and performance of an airborne sea surface salinity mapping system SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE Great Barrier Reef; sea surface salinity mapping system; scanning low frequency microwave radiometer ID WATERS; OCEAN AB Input of freshwater from rivers is a critical consideration in the study and management of coral and seagrass ecosystems in tropical regions. Low salinity water can transport natural and manmade river-borne contaminants into the sea, and can directly stress marine ecosystems that are adapted to higher salinity levels. An efficient method of mapping surface salinity distribution over large ocean areas is required to address such environmental issues. We describe here an investigation of the utility of airborne remote sensing of sea surface salinity using an L-band passive microwave radiometer. The study combined aircraft overflights of the scanning low frequency microwave radiometer (SLFMR) with shipboard and in situ instrument deployments to map surface and subsurface salinity distributions, respectively, in the Great Barrier Reef Lagoon. The goals of the investigation were (a) to assess the performance of the airborne salinity mapper; (b) to use the maps and in situ data to develop an integrated description of the structure and zone of influence of a river plume under prevailing monsoon weather conditions; and (c) to determine the extent to which the sea surface salinity distribution expressed the subsurface structure. The SLFMR was found to have sufficient precision (1 psu) and accuracy ( similar to 3 psu) to provide a useful description of plumes emanating from estuaries of moderate discharge levels with a salinity range of 16 to 32 psu in the open sea. The aircraft surveys provided a means of rapidly assessing the spatial extent of the surface salinity distribution of the plume, while in situ data revealed subsurface structure detail and provided essential validation data for the SLFMR. The combined approach allowed us to efficiently determine the structure and zone of influence of the plume, and demonstrated the utility of sea surface salinity remote sensing for studying coastal circulation in tropical seas. (C) 2003 Published by Elsevier Science Inc. C1 Univ So Mississippi, Dept Marine Sci, Stennis Space Ctr, Hattiesburg, MS 39529 USA. Australian Inst Marine Sci, Townsville, Qld 4810, Australia. James Cook Univ N Queensland, Sch Math & Phys Sci, Townsville, Qld 4811, Australia. Flinders Univ S Australia, Airborne Res Australia, Adelaide, SA 5106, Australia. RP Univ So Mississippi, Dept Marine Sci, Stennis Space Ctr, 1020 Balch Blvd, Hattiesburg, MS 39529 USA. EM Derek.Burrage@usm.edu NR 32 TC 23 Z9 24 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 EI 1879-0704 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAY 15 PY 2003 VL 85 IS 2 BP 204 EP 220 DI 10.1016/S0034-4257(02)00206-7 PG 17 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 668LF UT WOS:000182291900006 ER PT J AU Ecker, AJ Maislin, G Bersamira, C Price, NJ Powell, JV Rogers, NL Mallis, MM Dinges, DF AF Ecker, AJ Maislin, G Bersamira, C Price, NJ Powell, JV Rogers, NL Mallis, MM Dinges, DF TI Correlation between PERCLOS (percentage of eyelid closure) and auditory vigilance lapses during 42 hours of sustained wakefulness SO SLEEP LA English DT Meeting Abstract CT 17th Annual Meeting of the Associated-Professional-Sleep-Societies CY JUN 03-08, 2003 CL CHICAGO, ILLINOIS SP Assoc Prof Sleep Soc C1 Univ Penn, Dept Psychiat, Philadelphia, PA 19104 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RI Rogers, Naomi/G-3538-2013 OI Rogers, Naomi/0000-0002-0536-9814 NR 0 TC 2 Z9 2 U1 0 U2 0 PU AMER ACADEMY SLEEP MEDICINE PI WESTCHESTER PA ONE WESTBROOK CORPORATE CENTER STE 920, WESTCHESTER, IL 60154 USA SN 0161-8105 J9 SLEEP JI Sleep PD MAY 15 PY 2003 VL 26 BP A206 EP A206 PG 1 WC Clinical Neurology; Neurosciences SC Neurosciences & Neurology GA 677ZY UT WOS:000182841100513 ER PT J AU Mallis, MM Oyung, RL Reduta, DD AF Mallis, MM Oyung, RL Reduta, DD TI Morningness-eveningness assessed in commercial aviators SO SLEEP LA English DT Meeting Abstract CT 17th Annual Meeting of the Associated-Professional-Sleep-Societies CY JUN 03-08, 2003 CL CHICAGO, ILLINOIS SP Assoc Prof Sleep Soc C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. San Jose State Univ, San Jose, CA 95192 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER ACADEMY SLEEP MEDICINE PI WESTCHESTER PA ONE WESTBROOK CORPORATE CENTER STE 920, WESTCHESTER, IL 60154 USA SN 0161-8105 J9 SLEEP JI Sleep PD MAY 15 PY 2003 VL 26 BP A112 EP A112 PG 1 WC Clinical Neurology; Neurosciences SC Neurosciences & Neurology GA 677ZY UT WOS:000182841100277 ER PT J AU Oyung, RL Mallis, MM AF Oyung, RL Mallis, MM TI Recovery sleep in flight crew spanning 30 days of flight activity SO SLEEP LA English DT Meeting Abstract CT 17th Annual Meeting of the Associated-Professional-Sleep-Societies CY JUN 03-08, 2003 CL CHICAGO, ILLINOIS SP Assoc Prof Sleep Soc C1 San Jose State Univ, San Jose, CA 95192 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER ACADEMY SLEEP MEDICINE PI WESTCHESTER PA ONE WESTBROOK CORPORATE CENTER STE 920, WESTCHESTER, IL 60154 USA SN 0161-8105 J9 SLEEP JI Sleep PD MAY 15 PY 2003 VL 26 BP A207 EP A207 PG 1 WC Clinical Neurology; Neurosciences SC Neurosciences & Neurology GA 677ZY UT WOS:000182841100515 ER PT J AU Price, NJ Maislin, G Powell, JW Ecker, AJ Szuba, MP Mallis, MM Dinges, DF AF Price, NJ Maislin, G Powell, JW Ecker, AJ Szuba, MP Mallis, MM Dinges, DF TI Unobtrusive detection of drowsiness-induced PVT lapses using infrared retinal reflectance of slow eyelid closures SO SLEEP LA English DT Meeting Abstract CT 17th Annual Meeting of the Associated-Professional-Sleep-Societies CY JUN 03-08, 2003 CL CHICAGO, ILLINOIS SP Assoc Prof Sleep Soc C1 Univ Penn, Dept Psychiat, Philadelphia, PA 19104 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 6 Z9 6 U1 0 U2 0 PU AMER ACADEMY SLEEP MEDICINE PI WESTCHESTER PA ONE WESTBROOK CORPORATE CENTER STE 920, WESTCHESTER, IL 60154 USA SN 0161-8105 J9 SLEEP JI Sleep PD MAY 15 PY 2003 VL 26 BP A177 EP A177 PG 1 WC Clinical Neurology; Neurosciences SC Neurosciences & Neurology GA 677ZY UT WOS:000182841100441 ER PT J AU Lundgren, P Berardino, P Coltelli, M Fornaro, G Lanari, R Puglisi, G Sansosti, E Tesauro, M AF Lundgren, P Berardino, P Coltelli, M Fornaro, G Lanari, R Puglisi, G Sansosti, E Tesauro, M TI Coupled magma chamber inflation and sector collapse slip observed with synthetic aperture radar interferometry on Mt. Etna volcano SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE Etna; volcano; deformation; radar; interferometry ID MOUNT-ETNA; SURFACE DEFORMATION; GROUND DEFORMATION; KILAUEA VOLCANO; SAR INTERFEROMETRY; RAPID DEFORMATION; PERNICANA FAULT; HALF-SPACE; TOPOGRAPHY; INTERFEROGRAMS AB Volcanoes deform dynamically due to changes in both their magmatic system and instability of their edifice. Mt. Etna features vigorous and almost continuous eruptive activity from its summit craters and periodic flank eruptions. Even though its shape is that of a large stratovolcano, its structure features two rift systems and a flank collapse structure similar to Hawaiian shield volcanoes. We analyze European remote sensing (ERS) satellite differential interferometric synthetic aperture radar (InSAR) data (1993-1996) for Mt. Etna spanning its quiescence from 1993 through the initiation of renewed eruptive activity in late 1995. We use synthetic aperture radar (SAR) data from both ascending and descending ERS satellite tracks. Comparison of independent interferograms covering the first 2 years of the inflationary period shows a pattern consistent with inflation of the volcano. Calculation of the tropospheric path delay based on meteorological data does not change this interpretation. Interferograms from late summer 1995-1996 show no significant deformation. Joint inversion of interferograms from ascending and descending satellite tracks require both inflation from a spheroidal magmatic source located beneath the summit at 5 km below sea level, and displacement of the east flank of Etna along a basal decollement. Both sources of deformation were contemporaneous within the resolution of our data and suggest that inflation of the central magma chamber acted to trigger slip of Etna's eastern flank. These results demonstrate that flank instability and recharge of a volcano's magma system must both be considered toward understanding how volcanoes work and in their hazard evaluation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CNR, IREA, I-80124 Naples, Italy. Ist Nazl Geofis & Vulcanol, I-95123 Catania, Italy. RP Lundgren, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-233, Pasadena, CA 91109 USA. EM paul@weed.jpl.nasa.gov RI Sansosti, Eugenio/F-7297-2011; Puglisi, Giuseppe/J-9015-2015; Coltelli, Mauro/F-1676-2015 OI Sansosti, Eugenio/0000-0002-5051-4056; Puglisi, Giuseppe/0000-0003-4503-5808; Coltelli, Mauro/0000-0001-7868-3946 NR 49 TC 62 Z9 63 U1 0 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAY 14 PY 2003 VL 108 IS B5 AR 2247 DI 10.1029/2001JB000657 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 682TD UT WOS:000183107700001 ER PT J AU Wang, HQ Richardson, MI Wilson, RJ Ingersoll, AP Toigo, AD Zurek, RW AF Wang, HQ Richardson, MI Wilson, RJ Ingersoll, AP Toigo, AD Zurek, RW TI Cyclones, tides, and the origin of a cross-equatorial dust storm on Mars SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GENERAL-CIRCULATION MODEL; HEMISPHERE; SIMULATION; DYNAMICS; EDDIES AB [1] We investigate the triggering mechanism of a cross-equatorial dust storm observed by Mars Global Surveyor in 1999. This storm, which had a significant impact on global mean temperatures, was seen in visible and infrared data to commence with the transport of linear dust fronts from the northern high latitudes into the southern tropics. However, other similar transport events observed in northern fall and winter did not lead to large dust storms. Based on off-line Lagrangian particle transport analysis using a high resolution Mars general circulation model, we propose a simple explanation for the diurnal, seasonal and interannual variability of this type of frontal activity, and of the resulting dust storms, that highlights the cooperative interaction between northern hemisphere fronts associated with low pressure cyclones and tidally-modified return branch of the Hadley circulation. C1 CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wang, HQ (reprint author), CALTECH, Dept Geol & Planetary Sci, MC 150-21, Pasadena, CA 91125 USA. NR 19 TC 44 Z9 44 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 13 PY 2003 VL 30 IS 9 AR 1488 DI 10.1029/2002GL016828 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 682PE UT WOS:000183100100003 ER PT J AU Chandra, S Ziemke, JR Martin, RV AF Chandra, S Ziemke, JR Martin, RV TI Tropospheric ozone at tropical and middle latitudes derived from TOMS/MLS residual: Comparison with a global model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE biomass burning; tropospheric ozone; stratospheric ozone; El Nino; global circulation model; tropopause ID SOUTH-ATLANTIC-OCEAN; 1997-1998 EL-NINO; STRATOSPHERIC OZONE; UNITED-STATES; COLUMN OZONE; WATER-VAPOR; 3-D MODELS; PACIFIC; CHEMISTRY; POLLUTION AB The tropospheric ozone residual method is used to derive zonal maps of tropospheric column ozone using concurrent measurements of total column ozone from Nimbus 7 and Earth Probe (EP) Total Ozone Mapping Spectrometer (TOMS) and stratospheric column ozone from the Microwave Limb Sounder (MLS) instrument on the Upper Atmosphere Research Satellite (UARS). Our study shows that the zonal variability in TOMS total column ozone at tropical and subtropical latitudes is mostly of tropospheric origin. The seasonal and zonal variability in tropospheric column ozone (TCO), derived from the TOMS/MLS residual, is consistent with that derived from the convective cloud differential method and ozonesonde measurements in regions where these data overlap. A comparison of TCO derived from the TOMS/MLS residual and a global three-dimensional model of tropospheric chemistry (GEOS-CHEM) for 1996-1997 shows good agreement in the tropics south of the equator. Both the model and observations show similar zonal and seasonal characteristics including an enhancement of TCO in the Indonesian region associated with the 1997 El Nino. Both show the decline of the wave-1 pattern from the tropics to the extratropics as lightning activity and the Walker circulation decline. Both show enhanced ozone in the downwelling branches of the Hadley Circulation near +/-30degrees. Model and observational differences increase with latitude during winter and spring. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Harvard Univ, Harvard Smithsonian Ctr Astrophys, Div Engn & Appl Sci, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. RP NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA. EM chandra@chapman.gsfc.nasa.gov; ziemke@jwocky.gsfc.nasa.gov; rvmartin@fas.harvard.edu RI Martin, Randall/A-2051-2008; Martin, Randall/C-1205-2014; Chem, GEOS/C-5595-2014 OI Martin, Randall/0000-0003-2632-8402; NR 57 TC 34 Z9 34 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 13 PY 2003 VL 108 IS D9 AR 4291 DI 10.1029/2002JD002912 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 682QN UT WOS:000183103300009 ER PT J AU King, MD Platnick, S Moeller, CC Revercomb, HE Chu, DA AF King, MD Platnick, S Moeller, CC Revercomb, HE Chu, DA TI Remote sensing of smoke, land, and clouds from the NASA ER-2 during SAFARI 2000 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE SAFARI 2000; airborne measurements; remote sensing; Terra; satellite measurements; aerosol optical properties ID IMAGING SPECTRORADIOMETER; INSTRUMENT DESCRIPTION; AEROSOL; CAMPAIGN; AERONET; MISR; SKY AB [1] The NASA ER-2 aircraft was deployed to southern Africa between 13 August and 25 September 2000 as part of the Southern African Regional Science Initiative ( SAFARI) 2000. This aircraft carried a sophisticated array of multispectral scanners, multiangle spectroradiometers, a monostatic lidar, a gas correlation radiometer, upward and downward spectral flux radiometers, and two metric mapping cameras. These observations were obtained over a 3200 x 2800 km region of savanna, woody savanna, open shrubland, and grassland ecosystems throughout southern Africa and were quite often coordinated with overflights by NASA's Terra and Landsat 7 satellites. The primary purpose of this high-altitude observing platform was to obtain independent observations of smoke, clouds, and land surfaces that could be used to check the validity of various remote sensing measurements derived by Earth-orbiting satellites. These include such things as the accuracy of the Moderate Resolution Imaging Spectroradiometer ( MODIS) cloud mask for distinguishing clouds and heavy aerosol from land and ocean surfaces and Terra analyses of cloud optical and microphysical properties, aerosol properties, leaf area index, vegetation index, fire occurrence, carbon monoxide, and surface radiation budget. In addition to coordination with Terra and Landsat 7 satellites, numerous flights were conducted over surface AERONET sites, flux towers in South Africa, Botswana, and Zambia, and in situ aircraft from the University of Washington, South Africa, and the United Kingdom. As a result of this experiment, the MODIS cloud mask was shown to distinguish clouds, cloud shadows, and fires over land ecosystems of southern Africa with a high degree of accuracy. In addition, data acquired from the ER-2 show the vertical distribution and stratification of aerosol layers over the subcontinent and make the first observations of a "blue spike'' spectral emission signature associated with air heated by fire advecting over a cooler land surface. C1 NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Wisconsin, Ctr Space Sci & Engn, Madison, WI 53706 USA. Sci Syst & Applicat Inc, Seabrook, MD USA. RP King, MD (reprint author), NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Code 900, Greenbelt, MD 20771 USA. EM michael.d.king@nasa.gov; steven.platnick@nasa.gov; chris.moeller@ssec.wisc.edu; hankr@ssec.wisc.edu; achu@climate.gsfc.nasa.gov RI King, Michael/C-7153-2011; Platnick, Steven/J-9982-2014 OI King, Michael/0000-0003-2645-7298; Platnick, Steven/0000-0003-3964-3567 NR 28 TC 14 Z9 14 U1 1 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 MAY 13 PY 2003 VL 108 IS D13 AR 8502 DI 10.1029/2002JD003207 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 682RD UT WOS:000183105100001 ER PT J AU Hudait, MK Lin, Y Wilt, DM Speck, JS Tivarus, CA Heller, ER Pelz, JP Ringel, SA AF Hudait, MK Lin, Y Wilt, DM Speck, JS Tivarus, CA Heller, ER Pelz, JP Ringel, SA TI High-quality InAsyP1-y step-graded buffer by molecular-beam epitaxy SO APPLIED PHYSICS LETTERS LA English DT Article ID THREADING DISLOCATION DENSITIES; INTERCONNECTED MODULES; HIGH-PERFORMANCE; QUANTUM-WELLS; LAYERS; SI; SURFACES AB Relaxed, high-quality, compositionally step-graded InAsyP1-y layers with an As composition of y=0.4, corresponding to a lattice mismatch of similar to1.3% were grown on InP substrates using solid-source molecular-beam epitaxy. Each layer was found to be nearly fully relaxed observed by triple axis x-ray diffraction, and plan-view transmission electron microscopy revealed an average threading dislocations of 4x10(6) cm(-2) within the InAs0.4P0.6 cap layer. Extremely ordered crosshatch morphology was observed with very low surface roughness (3.16 nm) compared to cation-based In0.7Al0.3As/InxAl1-xAs/InP graded buffers (10.53 nm) with similar mismatch and span of lattice constants on InP. The results show that InAsyP1-y graded buffers on InP are promising candidates as virtual substrates for infrared and high-speed metamorphic III-V devices. (C) 2003 American Institute of Physics. C1 Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Calif Santa Barbara, Dept Mat Sci, Santa Barbara, CA 93106 USA. Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. RP Ringel, SA (reprint author), Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. RI Speck, James/H-5646-2011 NR 14 TC 30 Z9 30 U1 1 U2 5 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 12 PY 2003 VL 82 IS 19 BP 3212 EP 3214 DI 10.1063/1.1572476 PG 3 WC Physics, Applied SC Physics GA 675VV UT WOS:000182717900023 ER PT J AU Turyshev, SG Andersson, BG AF Turyshev, SG Andersson, BG TI The 550-au Mission: a critical discussion SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Editorial Material DE gravitation; gravitational lensing; space vehicles : instruments; telescopes; astrometry; Sun : general ID HIGH-RESOLUTION AB We have studied the science rationale, goals and requirements for a mission aimed at using the gravitational lensing from the Sun as a way of achieving high angular resolution and high signal amplification. We find that such a mission concept is compromised by several practical problems. Most severe are the effects due to the plasma in the solar atmosphere which cause refraction and scattering of the propagating rays. These effects either limit the frequencies that can be observed to those above similar to1 THz, or they move the optical point outwards beyond the vacuum value of greater than or equal to550 au. (Thus for observing frequency of 300 GHz the optical point is moved outwards to similar to 680 au.) Density fluctuations in the inner solar atmosphere will further cause random pathlength differences for different rays. The corrections for the radiation from the Sun itself will also be a major challenge at any wavelength used, but could be mitigated with coronographic techniques. Given reasonable constraints on the spacecraft (particularly in terms of size and propulsion), source selection as well as severe navigational constraints further add to the difficulties for a potential mission. Nevertheless, unbiased surveys of small-scale structure on the sky at short wavelengths might be the most promising application of such a mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Turyshev, SG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 5 Z9 5 U1 2 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 MAY 11 PY 2003 VL 341 IS 2 BP 577 EP 582 DI 10.1046/j.1365-8711.2003.06428.x PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 674TE UT WOS:000182651400016 ER PT J AU Prentice, AJR Dyt, CP AF Prentice, AJR Dyt, CP TI A numerical simulation of supersonic turbulent convection relating to the formation of the Solar system SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE convection; turbulence; Sun : atmospheric motions; Solar system : formation ID BULK CHEMICAL-COMPOSITION; FLUX-CORRECTED TRANSPORT; COMPRESSIBLE CONVECTION; DEEP ATMOSPHERE; ORIGIN; EVOLUTION; GANYMEDE AB A flux-corrected transport scheme due to Zalesak is used to carry out a numerical simulation of thermal convection in a two-dimensional layer of ideal, diatomic gas, which is heated from below and stratified gravitationally across many pressure scaleheights. The purpose of this calculation is to mimic the physical conditions in the outer layers of the protosolar cloud (PSC) from which the Solar system formed. The temperature T-0 at the top boundary (z = 0) and the dimensionless temperature gradient theta= (d /T (0) )partial derivativeT /partial derivativez at the base of the layer of thickness d are kept fixed, with theta= 10. The initial atmosphere is uniformly superadiabatic, having polytropic index m (in) = 1. Because the Reynolds number of the real atmosphere is so large, a subgrid-scale (SGS) turbulence approximation due to Smagorinsky is used to model the influence of motions with length-scale less than the computational grid size. The flow soon evolves to a network of giant convective cells, which span the whole layer. At cell boundaries the downflows are spatially concentrated and rapid while the upflows are broad and sluggish. The peak downflow Mach number is at depth z = 0.55d. The descent of the cold gas eliminates much of the initial superadiabatic structure of the atmosphere for z greater than or similar to 0.1d, thereby reducing the long-term mean temperature gradient and causing a net shift of mass towards the base. In the top 10 per cent of depth, SGS modelling causes to increase sharply. A steep density inversion occurs with the long-term mean density at the top boundary rising to 3.5 times the initial density rho(0) there. This result gives new credibility to the modern Laplacian theory (MLT) of Solar system origin. Here a postulated 35-fold density increase at the surface of the PSC causes the shedding of discrete gas rings at the observed mean orbital spacings of the planets. Even so, further numerical simulations, corresponding to higher values of theta, which may yield values and , are required before the MLT can be considered to be valid. C1 CSIRO, Div Petr Resources, Kensington, WA 6151, Australia. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CSIRO, Div Petr Resources, Box 28M, Kensington, WA 6151, Australia. EM andrew.prentice@sci.monash.edu.au; chris.dyt@csiro.au NR 40 TC 5 Z9 5 U1 0 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0035-8711 EI 1365-2966 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 11 PY 2003 VL 341 IS 2 BP 644 EP 656 DI 10.1046/j.1365-8711.2003.06454.x PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 674TE UT WOS:000182651400023 ER PT J AU Piner, BG Unwin, SC Wehrle, AE Zook, AC Urry, CM Gilmore, DM AF Piner, BG Unwin, SC Wehrle, AE Zook, AC Urry, CM Gilmore, DM TI The speed and orientation of the parsec-scale jet in 3C 279 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : jets; quasars : individual (3C 279); radiation mechanisms : nonthermal; radio continuum : galaxies ID EXTRAGALACTIC RADIO-SOURCES; ACTIVE GALACTIC NUCLEI; BASE-LINE INTERFEROMETRY; FLUX-DENSITY VARIATIONS; BL-LACERTAE OBJECTS; GAMMA-RAY SOURCES; QUASAR 3C 345; X-RAY; BRIGHTNESS TEMPERATURE; MULTIWAVELENGTH OBSERVATIONS AB A high degree of relativistic beaming is inferred for the jets of blazars on the basis of several lines of evidence, but the intrinsic speed and angle of the jet to the line of sight for individual sources are difficult to measure. We have calculated inverse Compton Doppler factors for 3C 279 using the collection of VLBI data (including high-resolution space VLBI data at low frequencies) recently published by us (as Wehrle et al. and Piner et al.) and the collection of multiwavelength spectra recently published by Hartman et al. From the Doppler factor and superluminal apparent speed, we then calculate the Lorentz factor and angle to the line of sight of the parsec-scale relativistic jet. We follow the method previously used by Unwin et al. for 3C 345 to model the jet components as homogeneous spheres and the VLBI core as an unresolved inhomogeneous conical jet, using Konigl's formalism. The conical jet model can be made to match both the observed X-ray emission and the VLBI properties of the core with a suitable choice of Doppler factor, implying that the core makes a significant contribution to the X-ray emission, in contrast to the situation for 3C 345, where the jet components dominated the X-ray emission. The parameters of the Konigl models indicate that the jet is particle dominated at the radii that produce significant emission (from similar to5 to 20 pc from the apex of the jet for most models) and is not in equipartition. At the inner radius of the Konigl jet the magnetic field is of order 0.1 G and the relativistic-particle number density is of order 10 cm(-3). The kinetic energy flux in the jet is of order 10(46) (1+k) ergs s(-1), where k is the ratio of proton to electron energy, which implies a mass accretion rate of order 0.1(1+k)/eta M-circle dot yr(-1), where eta is the efficiency of conversion of mass to kinetic energy. When all components are included in the calculation, then on average the core produces about half of the X-rays, with the other half being split between the long-lived component C4 and the brightest inner-jet component. We calculate an average speed and angle to the line of sight for the region of the jet interior to 1 mas of v=0.992c (gamma=8) and theta=4degrees and an average speed and angle to the line of sight for C4 (at rapproximate to3 mas) of v=0.997c (gamma=13) and theta=2degrees. These values imply average Doppler factors of delta=12 for the inner jet and delta=21 for C4. C1 Whittier Coll, Dept Phys & Astron, Whittier, CA 90608 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Interferometry Sci Ctr, Pasadena, CA 91109 USA. Pomona Coll, Dept Phys & Astron, Claremont, CA 91711 USA. Yale Univ, Dept Phys, New Haven, CT 06520 USA. Space Telescope Sci Inst, Sci Comp & Res Support Div, Baltimore, MD 21218 USA. RP Whittier Coll, Dept Phys & Astron, 13406 E Philadelphia St, Whittier, CA 90608 USA. EM gpiner@whittier.edu; stephen.c.unwin@jpl.nasa.gov; ann.e.wehrle@jpl.nasa.gov; azook@pomona.edu; meg.urry@yale.edu; dgilmore@stsci.edu RI Urry, Claudia/G-7381-2011 OI Urry, Claudia/0000-0002-0745-9792 NR 55 TC 20 Z9 21 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 10 PY 2003 VL 588 IS 2 BP 716 EP 730 DI 10.1086/374212 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 680RV UT WOS:000182991900007 ER PT J AU Holt, SS Schlegel, EM Hwang, U Petre, R AF Holt, SS Schlegel, EM Hwang, U Petre, R TI Chandra observation of the X-ray source population of NGC 6946 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 6946); X-rays : binaries; X-rays : galaxies; X-rays : general ID SPIRAL GALAXY NGC-6946; ULTRALUMINOUS SUPERNOVA REMNANT; POINT SOURCES; LUMINOSITY; COMPLEX; STARBURST; M101; BAR; M31 AB We present the results of a study of discrete X-ray sources in NGC 6946 using a deep Chandra ACIS observation. Based on the slope of the log N-log S distribution and the general correlation of sources with the spiral arms, we infer that the overall discrete source sample in NGC 6946 is dominated by high-mass X-ray binaries, in contrast to the source distributions in M31 and the Milky Way. This is consistent with the higher star formation rate in NGC 6946 than in those galaxies. We find that the strong X-ray sources in the region of the galactic center do not correlate in detail with images of the region in the near-IR, although one of them may be coincident with the galactic center. The noncentral ultraluminous X-ray source in NGC 6946, previously identified with a supernova remnant, has an X-ray spectrum and luminosity that is inconsistent with either a traditional pulsar wind nebula or a blast wave remnant. C1 Franklin W Olin Coll Engn, Needham, MA 02492 USA. Harvard Smithsonian Ctr Astrophys, Smithsonian Astrophys Observ, Harvard Coll Observ, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Holt, SS (reprint author), Franklin W Olin Coll Engn, 1735 Great Plain Ave, Needham, MA 02492 USA. NR 33 TC 29 Z9 29 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 2003 VL 588 IS 2 BP 792 EP 800 DI 10.1086/374311 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 680RV UT WOS:000182991900013 ER PT J AU Padoan, P Goodman, AA Juvela, M AF Padoan, P Goodman, AA Juvela, M TI The spectral correlation function of molecular clouds: A statistical test for theoretical models SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : individual (Perseus, Rosette Molecular Complex, Taurus Molecular Cloud); ISM : kinematics and dynamics; radio lines : ISM; turbulence ID LTE RADIATIVE-TRANSFER; STAR-FORMING REGIONS; VELOCITY-FIELD STATISTICS; LARGE-MAGELLANIC-CLOUD; SMALL-SCALE STRUCTURE; INTERSTELLAR CLOUDS; ROTATIONAL-EXCITATION; COLUMN DENSITIES; TURBULENT CLOUDS; TAURUS AB We compute the spectral correlation function (SCF) of (CO)-C-13 J=1-0 maps of molecular cloud complexes. The SCF is a power law over approximately an order of magnitude in spatial separation in every map. The power-law slope of the SCF, alpha, its normalization, S-0(1 pc), and the spectral line width averaged over the whole map, sigma(v), are computed for all the observational maps. The values of alpha, S-0(1 pc), and sigma(v) are combined to obtain empirical correlations to be used as tests for theoretical models of molecular clouds. Synthetic spectral maps are computed from different theoretical models, including solutions of the magnetohydrodynamic (MHD) equations with different values of the rms Mach number of the flow and stochastic models with different power spectra of the velocity field. In order to compute the radiative transfer from the MHD models, it is necessary to assign the models a physical scale and a physical density. When these assignments are made according to Larson-type relations, the best fit to the observational correlations is obtained. Unphysical stochastic models are instead ruled out by the empirical correlations. MHD models with equipartition of magnetic and kinetic energy of turbulence do not reproduce the observational data when their average magnetic field is oriented approximately parallel to the line of sight. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Univ, Dept Astron, Cambridge, MA 02138 USA. Univ Helsinki, Univ Helsinki Observ, SF-00014 Helsinki, Finland. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 169-506, Pasadena, CA 91109 USA. EM padoan@jpl.nasa.gov RI Juvela, Mika/H-6131-2011; Goodman, Alyssa/A-6007-2010; OI Juvela, Mika/0000-0002-5809-4834; Goodman, Alyssa/0000-0003-1312-0477; Padoan, Paolo/0000-0002-5055-5800 NR 56 TC 26 Z9 27 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 10 PY 2003 VL 588 IS 2 BP 881 EP 893 DI 10.1086/374240 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 680RV UT WOS:000182991900021 ER PT J AU Band, DL AF Band, DL TI Comparison of the gamma-ray burst sensitivity of different detectors SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID BATSE AB Gamma-ray burst detectors are sensitive at different energies, complicating the comparison of the burst populations that they detect. Instrument teams often report their detector sensitivities in their instruments' energy band. I propose that sensitivities be reported as the threshold peak photon flux F-T over the 1-1000 keV energy band for a specific spectral shape. The primary spectral parameter is E-p, the energy of the maximum E-2 N(E) proportional to nuf(nu). Thus, F-T versus E-p is a useful description of a detector's sensitivity. I find that Swift will be marginally more sensitive than BATSE for E-p > 100 keV but significantly more sensitive for E-p < 100 keV. Because of its low energy sensitivity, the FREGATE on HETE-2 is surprisingly sensitive below E-p = 100 keV. Both the WFC on BeppoSAX and the WXM on HETE-2 are/were sensitive for low E-p. As expected, the GBM on GLAST will be less sensitive than BATSE, while EXIST will be significantly more sensitive than Swift. The BeppoSAX GRBM was less sensitive that the WFC, particularly at low E-p. C1 NASA, Goddard Space Flight Ctr, Gamma Ray Large Area Space Telescope SSC, Greenbelt, MD 20771 USA. RP Univ Maryland, Dept Phys, Joint Ctr Astrophys, 1000 Hilltop Circle, Baltimore, MD 21250 USA. EM dband@lheapop.gsfc.nasa.gov NR 18 TC 87 Z9 87 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 10 PY 2003 VL 588 IS 2 BP 945 EP 951 DI 10.1086/374242 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 680RV UT WOS:000182991900026 ER PT J AU Roberts, MSE Tam, CR Kaspi, VM Lyutikov, M Vasisht, G Pivovaroff, M Gotthelf, EV Kawai, N AF Roberts, MSE Tam, CR Kaspi, VM Lyutikov, M Vasisht, G Pivovaroff, M Gotthelf, EV Kawai, N TI The pulsar wind nebula in G11.2-0.3 SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : general; pulsars : individual (AX J1811.5-1926); stars : neutron; supernovae : individual (G11.2-0.3); X-rays : general ID SUPERNOVA REMNANT G11.2-0.3; X-RAY OBSERVATIONS; MAGNETIC-FIELD; CRAB-NEBULA; RADIO; LUMINOSITY; EVOLUTION; PARTICLES; MODEL; ASCA AB We present an X-ray and radio study of the wind nebula surrounding the central pulsar PSR J1811-1925 in the supernova remnant G11.2-0.3. Using high-resolution data obtained with the Chandra X-Ray Observatory and with the VLA radio telescope, we show the X-ray and radio emission is asymmetric around the pulsar, despite the latter's central position in the very circular shell. The new X-ray data allow us to separate the synchrotron emission of the pulsar wind nebula from the surrounding thermal emission and that from the pulsar itself. On the basis of X-ray data from two epochs, we observe temporal variation of the location of X-ray hot spots near the pulsar, indicating relativistic motion. We compare thermal emission observed within the shell, which may be associated with the forward shock of the pulsar wind nebula, to thermal emission from a nearby portion of the remnant shell, the temperature of which implies an expansion velocity consistent with the identification of the remnant with the historical event of 386 A.D. The measured X-ray and radio spectral indices of the nebula synchrotron emission are found to be consistent with a single synchrotron cooling break. The magnetic field implied by the break frequency is anomalously large, given the apparent size and age of the nebula, if a spherical morphology is assumed but is consistent with a bipolar morphology. C1 McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Tokyo Inst Technol, Dept Phys, Meguro Ku, Tokyo 1528551, Japan. RP Roberts, MSE (reprint author), MIT, Dept Phys, Cambridge, MA 02139 USA. RI Pivovaroff, Michael/M-7998-2014; OI Pivovaroff, Michael/0000-0001-6780-6816; Roberts, Mallory/0000-0002-9396-9720 NR 30 TC 47 Z9 48 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 2003 VL 588 IS 2 BP 992 EP 1002 DI 10.1086/374266 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 680RV UT WOS:000182991900030 ER PT J AU Hillier, DJ Lanz, T Heap, SR Hubeny, I Smith, LJ Evans, CJ Lennon, DJ Bouret, JC AF Hillier, DJ Lanz, T Heap, SR Hubeny, I Smith, LJ Evans, CJ Lennon, DJ Bouret, JC TI A tale of two stars: The extreme O7 Iaf+ supergiant AV 83 and the OC7.5 III((f)) star AV 69 SO ASTROPHYSICAL JOURNAL LA English DT Article DE Magellanic Clouds; stars : abundances; stars : atmospheres; stars : individual (AV 69, AV 83); ultraviolet : stars ID RADIATION-DRIVEN WINDS; ULTRAVIOLET-SPECTROSCOPIC-EXPLORER; HOT LUMINOUS STARS; WOLF-RAYET STARS; INCLUDING SPHERICAL EXTENSION; SMALL-MAGELLANIC-CLOUD; PURE ABSORPTION-MODEL; MASS-LOSS RATES; ATOMIC DATA; STELLAR WINDS AB We present a detailed study of AV 83, an O7 Iaf+ supergiant, and AV 69 [ OC7.5 III((f))] in the SMC. The stars have similar effective temperatures and luminosities but show very different wind signatures. For our study we have used the non-LTE line-blanketed atmosphere code developed by Hillier and Miller, which explicitly allows for line blanketing by C, N, O, S, Ar, Ne, Fe, and other elements. Our study finds that AV 83 has an effective temperature of approximately 33,000 K and log g approximate to 3.25. It has an extended photosphere as a result of a "low'' effective surface gravity and a much denser wind than main-sequence O stars. We can match the spectrum only by using a slow velocity law with beta approximate to 2, a value that is much larger than the values of around 1 predicted by standard radiation wind theory. Further, we show that the Halpha emission pro. le in AV 83 is sensitive to the adopted surface gravity. To fit the spectrum of AV 83, we have considered conventional models in which the wind is smooth and alternate models in which the winds are highly clumped. Both types of winds yield a satisfactory fit to the majority of lines in the observed spectrum; however, strong UV photospheric lines and the P V resonance transitions favor a clumped wind. If clumping is important, it must begin at relatively low velocities (i.e., 30 km s(-1), not 300 km s(-1)). In the smooth wind, the line force is too small to drive the wind. In the clumped wind, the line force is generally sufficient to drive the wind, although there are still some discrepancies around the sonic point. In AV 83, the N abundance is substantially enhanced relative to normal SMC abundances, while both C and O are SMC-like, consistent with the presence of internally processed CNO material at the stellar surface. The N III lambda4640 multiplet, which is known to be produced by dielectronic recombination, is well reproduced by the models. These lines, and the adjacent C III lambda4649 multiplet, show a significant sensitivity to surface gravity, as well as the usual sensitivity to abundance and effective temperature. Incoherent electron scattering, occurring within the photosphere, can explain the broad wings seen on these lines. We have modeled the Fe spectrum (Fe IV-Fe VI) in the UV in both AV 83 and AV 69. For stars with an effective temperature around 33,000 K, the Fe IV-to-Fe v line ratios form a useful effective temperature diagnostic and give results consistent with those found from optical and UV line diagnostics. The derived iron abundance, which is sensitive to the adopted microturbulent velocity, is 0.2-0.4 times the solar iron abundance in AV 83, while 0.2 solar gives a good fit for AV 69. The wind of AV 69 is substantially less dense than that of AV 83. Because of the lack of suitable diagnostics, it is impossible to constrain the mass-loss rate and velocity law independently. Its spectrum indicates that it has a similar effective temperature to AV 83 (T-eff approximate to 34; 000 K), a substantially higher gravity (log g = 3.5) than AV 83, and a CNO abundance pattern that has not been influenced by internal CNO processing. We show that the N/C abundance ratio is substantially below solar, in agreement with SMC nebular and stellar abundance studies. The differences between the spectra of AV 83 and AV 69, and between the derived masses and surface abundances, are striking. We have examined possible causes, and only one seems consistent with the observations and our current understanding of massive star evolution. AV 83 was most likely a fast rotator that experienced rotatio The presence of enhanced N but almost normal C and O abundances is a direct indication of rotationally induced mixing. On the other hand, AV 69 is a slow rotator. As part of our analyses, we have systematically examined the influence of the H/He abundance ratio, the mass-loss rate, the velocity law, the Fe abundance, microturbulence, and clumping on the theoretical spectrum. We illustrate which lines provide useful diagnostics and highlight some of the difficulties associated with spectroscopic analyses of O stars. The spectrum of AV 83 shows the presence of photospheric absorption lines, the presence of lines formed at the base of the wind, and numerous wind lines. Since these lines sample the photosphere and the entire wind, extreme O If supergiants, such as AV 83, are ideal candidates to probe conditions in stellar winds and hence further our knowledge of O star winds. C1 Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. UCL, Dept Phys & Astron, London WC1E 6BT, England. Isaac Newton Grp Telescopes, Santa Cruz De La Palma 38700, Spain. Astrophys Lab, Marseille, France. RP Univ Pittsburgh, Dept Phys & Astron, 3941 Ohara St, Pittsburgh, PA 15260 USA. RI heap, sara/E-2237-2012 NR 94 TC 138 Z9 139 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 2003 VL 588 IS 2 BP 1039 EP 1063 DI 10.1086/374329 PN 1 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 680RV UT WOS:000182991900034 ER PT J AU Sudarsky, D Burrows, A Hubeny, I AF Sudarsky, D Burrows, A Hubeny, I TI Theoretical spectra and atmospheres of extrasolar giant planets SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : general; molecular processes; planetary systems; planets and satellites : general; radiative transfer; stars : low-mass, brown dwarfs ID MASS DWARF STARS; BROWN DWARF; KECK INTERFEROMETER; OPTICAL-PROPERTIES; M4 DWARF; CHEMISTRY; JUPITER; ABUNDANCES; ACETYLENE; COMPANION AB We present a comprehensive theory of the spectra and atmospheres of irradiated extrasolar giant planets. We explore the dependences on stellar type, orbital distance, cloud characteristics, planet mass, and surface gravity. Phase-averaged spectra for specific known extrasolar giant planets that span a wide range of the relevant parameters are calculated, plotted, and discussed. The connection between atmospheric composition and emergent spectrum is explored in detail. Furthermore, we calculate the effect of stellar insolation on brown dwarfs. We review a variety of representative observational techniques and programs for their potential for direct detection, in light of our theoretical expectations, and we calculate planet-to-star flux ratios as a function of wavelength. Our results suggest which spectral features are most diagnostic of giant planet atmospheres and reveal the best bands in which to image planets of whatever physical and orbital characteristics. C1 Univ Arizona, Dept Astron, Tucson, AZ 85721 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. RP Univ Arizona, Dept Astron, Tucson, AZ 85721 USA. NR 94 TC 187 Z9 188 U1 1 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2003 VL 588 IS 2 BP 1121 EP 1148 DI 10.1086/374331 PN 1 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 680RV UT WOS:000182991900040 ER PT J AU Jin, LH So, RM Gatski, TB AF Jin, LH So, RM Gatski, TB TI Equilibrium states of turbulent homogeneous buoyant flows SO JOURNAL OF FLUID MECHANICS LA English DT Article ID REYNOLDS-STRESS CLOSURES; STABLY STRATIFIED MEDIUM; HEAT-TRANSFER MODEL; SHEAR-FLOW; SCALAR FLUX; NUMERICAL SIMULATIONS; TEMPERATURE-GRADIENT; CHANNEL FLOW; EVOLUTION; PREDICTION AB The equilibrium states of homogeneous turbulent buoyant flows are investigated through a fixed-point analysis of the evolution equations for the Reynolds stress anisotropy tensor and the scaled heat flux vector. The mean velocity and thermal fields are assumed to be two-dimensional. Scalar invariants formed from the Reynolds stress anisotropy tensor, the scaled heat flux vector, and the strain rate and rotation rate tensors are governed by a closed set of algebraic equations derived for the stress anisotropy and scaled heat flux under a (weak) equilibrium assumption. Six equilibrium state variables are identified for the buoyant case and contrasted with the corresponding two state variables obtained for the non-buoyant homogeneous turbulence case. These results, while dependent on the functional forms of the models for the pressure-strain rate correlation tensor and the pressure-scalar-gradient correlation and viscous dissipation vector, can be used as in the non-buoyant case to either calibrate new closure models or validate the performance of existing models. In addition, since the analysis only involves the turbulent time scales (both velocity and thermal) and their ratio, the results of the analysis are independent of the specific models for the dissipation rates of the turbulent kinetic energy and the temperature variance. The analytical results are compared with model predictions as well as recent direct numerical simulation (DNS) data for buoyant shear flows. Good agreement with DNS data is obtained. C1 Tsing Hua Univ, Dept Engn Mech, Beijing 100084, Peoples R China. Hong Kong Polytech Univ, Dept Mech Engn, Kowloon, Hong Kong, Peoples R China. NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Hampton, VA 23681 USA. RP Jin, LH (reprint author), Tsing Hua Univ, Dept Engn Mech, Beijing 100084, Peoples R China. NR 46 TC 20 Z9 21 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH ST, NEW YORK, NY 10011-4221 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD MAY 10 PY 2003 VL 482 BP 207 EP 233 DI 10.1017/S002211200300404X PG 27 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 689VT UT WOS:000183514200009 ER PT J AU Juarez, MD Nilsson, M AF Juarez, MD Nilsson, M TI On the detection of water vapor profiles and thin moisture layers from atmospheric radio occultations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE GPS radio; occultations; temperature profiles; water vapor profiles; remote sensing; retrieval techniques; 1Dvar ID METEOROLOGY; CLIMATE AB [1] GPS radio occultations provide high-resolution vertical profiles of the atmospheric refraction index that can be used to extract vertical profiles of tropospheric moisture content. A physical method to extract water abundances from refraction index profiles without using ancillary data or model input is described. The ability to capture sharp water structures in the upper troposphere is illustrated by comparisons with current approaches, individual radiosonde measurements, and statistics against global circulation analyses from the National Centers for Environmental Prediction and European Centre for Medium-Range Weather Forecasts. It is shown that thin layers of significant moisture variability can be detected and that atmospheric water profiles can be retrieved even in cases where the ancillary data are not optimal. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Chalmers Univ Technol, Dept Radio & Space Sci, Onsala Space Observ, SE-43992 Onsala, Sweden. RP Juarez, MD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM mtj@jpl.nasa.gov; f96mani@dd.chalmers.se NR 16 TC 0 Z9 0 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 MAY 9 PY 2003 VL 109 IS D9 AR 4276 DI 10.1029/2002JD002880 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 678PD UT WOS:000182874900002 ER PT J AU Beacom, JF Bell, NF Hooper, D Pakvasa, S Weiler, TJ AF Beacom, JF Bell, NF Hooper, D Pakvasa, S Weiler, TJ TI Decay of high-energy astrophysical neutrinos SO PHYSICAL REVIEW LETTERS LA English DT Article ID OSCILLATIONS; CONSTRAINTS; MODEL AB Existing limits on the nonradiative decay of one neutrino to another plus a massless particle (e.g., a singlet Majoron) are very weak. The best limits on the lifetime to mass ratio come from solar neutrino observations and are tau/mgreater than or similar to10(-4) s/eV for the relevant mass eigenstate(s). For lifetimes even several orders of magnitude longer, high-energy neutrinos from distant astrophysical sources would decay. This would strongly alter the flavor ratios from the phi(nu e):phi(nu mu):phi(nu tau)=1:1:1 expected from oscillations alone and should be readily visible in the near future in detectors such as IceCube. C1 Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Univ Hawaii, Dept Phys & Astron, Honolulu, HI 96822 USA. KEK, Theory Grp, Tsukuba, Ibaraki 3050801, Japan. Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. RP Beacom, JF (reprint author), Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, POB 500, Batavia, IL 60510 USA. EM beacom@fnal.gov; nfb@fnal.gov; hooper@pheno.physics.wisc.edu; pakvasa@phys.hawaii.edu; tom.weiler@vanderbilt.edu OI Beacom, John/0000-0002-0005-2631 NR 30 TC 121 Z9 121 U1 0 U2 0 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 MAY 9 PY 2003 VL 90 IS 18 AR 181301 DI 10.1103/PhysRevLett.90.181301 PG 4 WC Physics, Multidisciplinary SC Physics GA 677TP UT WOS:000182823900005 PM 12785996 ER PT J AU Weinreb, S AF Weinreb, S TI Communication from space: Radio and optical SO SCIENCE LA English DT Letter C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Weinreb, S (reprint author), CALTECH, Jet Prop Lab, MS 168-214,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 2 Z9 2 U1 0 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 9 PY 2003 VL 300 IS 5621 BP 901 EP 902 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 675WD UT WOS:000182719800023 PM 12738834 ER PT J AU Joughin, I Padman, L AF Joughin, I Padman, L TI Melting and freezing beneath Filchner-Ronne Ice Shelf, Antarctica SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MASS-BALANCE; OCEAN; CIRCULATION; WATER; MODEL AB [1] We use remote-sensing data sets to evaluate the spatial distribution of melt beneath the Filchner-Ronne Ice Shelf (FRIS). The net melt rate of 83.4 +/- 24.8 Gtons/yr is 2.5-5 times lower than previous glaciological estimates, but is similar to existing oceanographic estimates. The spatial distribution, however, differs significantly from standard conceptual and numerical models in which most melt occurs along the grounding lines. Our results suggest most grounding-line melt is refrozen, while the dominant Ice Shelf Water (ISW) source is melting near the ice shelf front, probably associated with tidal action. This suggests that changes in ice shelf extent can impact ISW production rates in the Weddell Sea. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Earth & Space Res, Seattle, WA 98102 USA. RP Joughin, I (reprint author), CALTECH, Jet Prop Lab, M-S 300-235,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Joughin, Ian/A-2998-2008 OI Joughin, Ian/0000-0001-6229-679X NR 23 TC 87 Z9 88 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 8 PY 2003 VL 30 IS 9 AR 1477 DI 10.1029/2003GL016941 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 678NM UT WOS:000182873400005 ER PT J AU Treuhaft, RN Asner, GP Law, BE AF Treuhaft, RN Asner, GP Law, BE TI Structure-based forest biomass from fusion of radar and hyperspectral observations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID INTERFEROMETRIC RADAR; SAR; BACKSCATTER; TOPOGRAPHY; OREGON; LIDAR; INDEX; BAND AB [1] Forest biomass was estimated from the remotely sensed profiles of leaf area density. Biomass estimated from forest structure profiles may be more accurate than that determined from microwave power or optical radiance measurements. Multialtitude, airborne, C-band, radar interferometry produced relative density profiles, which were normalized by leaf area indices from airborne hyperspectral optical imagery, yielding the forest canopy leaf area density for 11 structurally diverse stands in Central Oregon. Fits of field biomass measurements to model functions of remotely sensed leaf area density produced agreement between the field and remotely sensed biomasses at the level of 25 tons/ha, or 16% of the average stand biomass. The errors in the field and remote sensing observations indicated that this level of agreement was significant with greater than 99.5% confidence. These results suggest that further demonstrations may lead to a set of model functions that enable global, structure-based biomass remote sensing. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Stanford Univ, Dept Global Ecol, Carnegie Inst Washington, Stanford, CA 94305 USA. Oregon State Univ, Coll Forestry, Corvallis, OR 97331 USA. RP Treuhaft, RN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS138-212, Pasadena, CA 91109 USA. RI Asner, Gregory/G-9268-2013; OI Asner, Gregory/0000-0001-7893-6421; Law, Beverly/0000-0002-1605-1203 NR 21 TC 25 Z9 28 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 8 PY 2003 VL 30 IS 9 AR 1472 DI 10.1029/2002GL016857 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 678NM UT WOS:000182873400004 ER PT J AU Kaufmann, M Gusev, OA Grossmann, KU Martin-Torres, FJ Marsh, DR Kutepov, AA AF Kaufmann, M Gusev, OA Grossmann, KU Martin-Torres, FJ Marsh, DR Kutepov, AA TI Satellite observations of daytime and nighttime ozone in the mesosphere and lower thermosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE mesosphere; ozone; CRISTA; lower thermosphere; ROSE; non-LTE ID NONLOCAL THERMODYNAMIC-EQUILIBRIUM; CRYOGENIC INFRARED SPECTROMETERS; TERRESTRIAL MIDDLE ATMOSPHERE; DOUBLE-RESONANCE MEASUREMENTS; ACCELERATED LAMBDA ITERATION; 9.6 MU-M; ATOMIC OXYGEN; HIGH-LATITUDE; DIURNAL VARIABILITY; UPPER-STRATOSPHERE AB [1] The global distribution of mesospheric and lower thermospheric ozone 9.6 mum infrared emissions was measured by the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) experiment during two Space Shuttle missions in November 1994 and August 1997. The radiances measured by CRISTA have been inverted to O-3 number densities in the 50-95 km range by using a nonlocal thermodynamic equilibrium model. A detailed sensitivity study of retrieved O-3 number densities has been carried out. The ozone abundance profiles show volume mixing ratios of 1-2 ppmv at the stratopause, 0.5 ppmv or less around 80 km, and typically 1 ppmv during daytime and 10 ppmv during nighttime at the secondary maximum. The agreement with other experiments is typically better than 25%. The global distribution of upper mesospheric ozone shows significant latitudinal gradients and an enhancement in the equatorial upper mesosphere. At the polar night terminator a third ozone maximum is observed. Three-dimensional model results indicate that the latitudinal gradients are significantly influenced by solar tides. C1 Univ Wuppertal, Dept Phys, D-42281 Wuppertal, Germany. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ Munich, Max Planck Inst Extraterr Phys, Inst Astron & Astrophys, D-81679 Munich, Germany. RP Kaufmann, M (reprint author), Forschungszentrum Julich, ICGI, Postfach 1913, D-52425 Julich, Germany. EM kaufmann@uni-wuppertal.de; oleg@crista.uni-wuppertal.de; gross@wpos2.physik.uni-wuppertal.de; f.martin-torres@larc.nasa.gov; marsh@ucar.edu; aak@usm.uni-muenchen.de RI Marsh, Daniel/A-8406-2008; Kaufmann, Martin/A-3905-2013; Martin-Torres, Francisco Javier/G-6329-2015 OI Marsh, Daniel/0000-0001-6699-494X; Martin-Torres, Francisco Javier/0000-0001-6479-2236 NR 76 TC 40 Z9 41 U1 1 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 MAY 7 PY 2003 VL 108 IS D9 AR 4272 DI 10.1029/2002JD002800 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 678PC UT WOS:000182874800002 ER PT J AU Dworkin, JP Lazcano, A Miller, SL AF Dworkin, JP Lazcano, A Miller, SL TI The roads to and from the RNA world SO JOURNAL OF THEORETICAL BIOLOGY LA English DT Article DE pre-RNA world; RNA world; ribose; deoxyribose; prebiotic evolution ID PREBIOTIC SYNTHESIS; NUCLEIC-ACIDS; RIBONUCLEOTIDE REDUCTASES; MOLECULAR EVOLUTION; PURINE NUCLEOSIDES; GENETIC APPARATUS; STRUCTURAL BASIS; DNA ENZYMES; ORIGIN; LIFE AB The historical existence of the RNA world, in which early life used RNA for both genetic information and catalytic ability, is widely accepted. However, there has been little discussion of whether protein synthesis arose before DNA or what preceded the RNA world (i.e. the pre-RNA world). We outline arguments of what route life may have taken out of the RNA world: whether DNA or protein followed. Metabolic arguments favor the possibility that RNA genomes preceded the use of DNA as the informational macromolecule. However, the opposite can also be argued based on the enhanced stability, reactivity, and solubility of 2-deoxyribose as compared to ribose. The possibility that DNA may have come before RNA is discussed, although it is a less parsimonious explanation than DNA following RNA. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Nacl Autonoma Mexico, Fac Ciencias, Mexico City 04510, DF, Mexico. Univ Calif San Diego, Dept Chem & Biochem, La Jolla, CA 92093 USA. RP Lazcano, A (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. EM jason.dworkin@nasa.gov; alar@hp.fciencias.unam.mx; smiller@ucsd.edu RI Dworkin, Jason/C-9417-2012 OI Dworkin, Jason/0000-0002-3961-8997 NR 98 TC 67 Z9 72 U1 6 U2 37 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-5193 J9 J THEOR BIOL JI J. Theor. Biol. PD MAY 7 PY 2003 VL 222 IS 1 BP 127 EP 134 DI 10.1016/S0022-5193(03)00020-1 PG 8 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA 678XX UT WOS:000182892900010 PM 12699739 ER PT J AU Bauschlicher, CW Ricca, A Mingo, N Lawson, J AF Bauschlicher, CW Ricca, A Mingo, N Lawson, J TI On the current flow for benzene-1,4-dithiol between two Au contacts SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ELECTRON-TRANSPORT; SINGLE MOLECULES AB The current flow for a benzene-1,4-dithiol molecule between two Au contacts is computed. For most configurations considered, the computed current is an order of magnitude larger than experiment, as found by other groups. When the benzene-1,4-dithiol is bonded to the top of an fee cluster of Au atoms, the current flow is significantly reduced, bringing it into better agreement with experiment. This represents an alternative to the previously proposed two molecule mechanism, as explanation of the experimental results. (C) 2003 Elsevier Science B.V. All rights reserved. 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, Mail Stop 230-3, Moffett Field, CA 94035 USA. EM bauschli@pegasus.arc.nasa.gov NR 17 TC 17 Z9 17 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 EI 1873-4448 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 6 PY 2003 VL 372 IS 5-6 BP 723 EP 727 DI 10.1016/S0009-2614(03)00486-X PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 677EZ UT WOS:000182795100018 ER PT J AU Ricca, A Bauschlicher, CW AF Ricca, A Bauschlicher, CW TI Interaction of a conjugated phenylene ethynylene trimer with a Au(111) surface SO CHEMICAL PHYSICS LETTERS LA English DT Article ID MONOLAYERS AB The interaction of 4-[4'-(phenylethynyl)-phenylethynyl]-benzenethiols (PPBSH) with Au(1 11) surfaces has been studied using density functional theory and a cluster model. For PPBSH perpendicular to the surface, the threefold hollow is the most favorable site, but the energy difference between this and the least favorable site is only about 9 kcal/mol. The most stable form of PPBSH on the surface is bent, therefore, PPBSH should only be perpendicular to the surface at higher coverages. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, Space Technol Div, Moffett Field, CA 94035 USA. RP Ricca, A (reprint author), NASA, Ames Res Ctr, Space Technol Div, Mail Stop 230-3, Moffett Field, CA 94035 USA. NR 12 TC 12 Z9 12 U1 0 U2 0 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 6 PY 2003 VL 372 IS 5-6 BP 873 EP 877 DI 10.1016/S0009-2614(03)00514-1 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 677EZ UT WOS:000182795100044 ER PT J AU Sukhotin, M Brown, ER Gossard, AC Driscoll, D Hanson, M Maker, P Muller, R AF Sukhotin, M Brown, ER Gossard, AC Driscoll, D Hanson, M Maker, P Muller, R TI Photomixing and photoconductor measurements on ErAs/InGaAs at 1.55 mu m SO APPLIED PHYSICS LETTERS LA English DT Article ID INGAAS; GAAS AB We report here the fabrication and demonstration of the photomixers made from In0.53Ga0.47As epitaxial material lattice-matched to InP. The material consists of layers of ErAs nanoparticles separated by InGaAs and compensated with Be to reduce the photocarrier lifetime to picosecond levels and to increase the resistivity to similar to100 Omega cm. Interdigitated-electrode and planar-antenna structures were fabricated by e-beam lithography and tested for dc electrical characteristics, 1.55-mum optical responsivity, and difference-frequency photomixing. The measured responsivity of 8 mA/W and photomixer output of >0.1 muW beyond 100 GHz are already comparable to GaAs photomixers and suggest that coherent THz generation is now feasible using the abundant 1.55-mum-semiconductor-laser and optical-fiber technologies. (C) 2003 American Institute of Physics. C1 Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA. Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sukhotin, M (reprint author), Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA. NR 10 TC 56 Z9 57 U1 5 U2 7 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 5 PY 2003 VL 82 IS 18 BP 3116 EP 3118 DI 10.1063/1.1567459 PG 3 WC Physics, Applied SC Physics GA 673FR UT WOS:000182570000060 ER PT J AU Watanabe, K Hartmann, DH Leising, MD The, LS AF Watanabe, K Hartmann, DH Leising, MD The, LS TI Constraining the cosmic star formation rate with the MeV background SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 7th International Symposium on Nuclei in the Cosmos (NIC7) CY JUL 08-12, 2002 CL FUJI, JAPAN SP Todai Int Symp, Univ Tokyo, Int Symp Minist Educ, Culture, Sports, Sci & Technol, Commemorat Assoc Japan World Exposit 1970, Japan Soc Promot Sci, Inoue Fdn Sci, Kajima Fdn, Natl Astron Observ Japan ID GALAXIES; UNIVERSE; HISTORY AB The Cosmic Gamma-ray Background (CGB) in the, MeV regime has been measured with several space missions. The origin of the CGB in this energy regime is believed to be dominated by gamma-rays from Type la supernovae. We calculate the CGB spectrum within the framework of FRW cosmology as a function of the cosmic star formation rate, SFR(z) [10]. Several estimates of the SFR(z) have been reported since the pioneering work of Madau et al. [5]. Here we discuss observational constraints on SFR(z) derived from models of the CGB. In particular, we consider the SFR obtained from Gamma-Ray Burst observations [6], which increases dramatically with redshift beyond z similar to 1 in contrast to most estimates which saturate or show a mild increase with redshift. Gamma-ray bursts may be the most powerful tracers of star formation in the early universe and thus provide signposts of the initial epoch of element synthesis. The star formation rate implied by GRB statistics results in a gamma-ray background that matches the observations more closely than that inferred from other tracers of star formation. This may provide some support for the GRB/SFR-paradigm, which in turn promises a powerful diagnostic of star formation, and thus cosmic chemical evolution, from the era of Population III stars to the present. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. RP NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM watanabe@lheapop.gsfc.nasa.gov NR 13 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 EI 1873-1554 J9 NUCL PHYS A JI Nucl. Phys. A PD MAY 5 PY 2003 VL 718 BP 425C EP 427C DI 10.1016/S0375-9474(03)00821-2 PG 3 WC Physics, Nuclear SC Physics GA 668VR UT WOS:000182314300072 ER PT J AU Emardson, TR Simons, M Webb, FH AF Emardson, TR Simons, M Webb, FH TI Neutral atmospheric delay in interferometric synthetic aperture radar applications: Statistical description and mitigation SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE radar interferometry; troposphere; InSAR; crustal deformation ID WATER-VAPOR; PRECIPITABLE WATER; TROPOSPHERE; DEFORMATION; SURFACE AB Variations in the refractive index of the atmosphere cause variations in satellite-based interferometric synthetic aperture radar (InSAR) observations. We can mitigate tropospheric effects by averaging N-independent interferograms. Because the neutral atmosphere is uncorrelated at timescales longer than 1 day, using this technique statistically reduces the variance, sigma(2), of the noise by a factor of N. Using zenith neutral atmospheric delays from Global Positioning System (GPS) data from the Southern California Integrated GPS Network, we find that the average variance depends on the distance between observations, L, and height difference, H, as sigma=c L-alpha+kH with estimated values for c, alpha, and k of about 2.5, 0.5, and 4.8, respectively, where sigma is in mm and L and H are in km. We expect that the value of alpha is largely site-independent but the value of c will depend on the water vapor variability of the area of interest. This model is valid over a range of L between approximately 10 and 800 km. Height differences between 0 and 3 km have been used in this analysis. For distances of 100 and 10 km with negligible height differences, sigma is estimated to be approximately 25 and 8 mm, respectively. For a given orbit revisit time and image archive duration, we calculate the number and duration (assumed constant) of interferograms required to achieve a desired sensitivity to deformation rate at a given length scale. Assuming neutral atmosphere is the dominant source of noise, a 30degrees look angle, and an image revisit time of 7 days, detection of a deformation rate of 1 mm yr(-1) over distances of 10 km requires about 2.2 years of continuous observations. Given our results, we suggest a data covariance structure to use when using InSAR data to constrain geophysical models. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Seismol Lab, Pasadena, CA 91125 USA. RP Emardson, TR (reprint author), CALTECH, Jet Prop Lab, MS 238-600,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM ragne_emardson@space.se; simons@caltech.edu; fhw@jpl.nasa.gov NR 22 TC 66 Z9 74 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAY 3 PY 2003 VL 108 IS B5 AR 2231 DI 10.1029/2002JB001781 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 760VJ UT WOS:000187855700001 ER PT J AU Herbert, F Schneider, NM Hendrix, AR Bagenal, F AF Herbert, F Schneider, NM Hendrix, AR Bagenal, F TI Hubble Space Telescope observations of sulfur ions in the Io plasma torus: New constraints on the plasma distribution SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE Io plasma torus; composition; HST observations; structure; electron temperature; ribbon ID JOVIAN MAGNETOSPHERE; VOYAGER-1 ENCOUNTER; ATOMIC DATABASE; EMISSION-LINES; IONIZED SULFUR; TEMPERATURE; SPECTRUM; JUPITER; DENSITY; MODEL AB During the Io plasma torus crossings by the Galileo spacecraft in late 1999 and early 2000 we observed the dawn ansa of the torus using the Hubble Space Telescope (HST). Here we analyze 74 FUV HST/Space Telescope Imaging Spectrograph observations (1150 less than or equal to lambda less than or equal to 1720 Angstrom) of the dawn ansa of the Io plasma torus made during Galileo's C23, I24, and I27 torus passages. These data include spectral scans at various System III longitudes plus two undispersed images of S(++) 1720 Angstrom emission. Because of simultaneous observations by other instruments, the full value of these data will be developed by joint analysis, but here we present our results for their independent value. The S(++) images show that the "ribbon'' feature seen at visible wavelengths in ground-based observations is also clearly present in the FUV. The spectral scans were fitted using a simple plasma emission model integrated along the line of sight in order to invert the line-of-sight density superposition under the assumption of local azimuthal symmetry. Fits to the S(+) 1256 Angstrom, S(++) 1199Angstrom, and S(+++) 1410 Angstrom emissions reveal that the S(++) and S(+++) densities peak similar to0.2 R(J) farther from Jupiter than does the S(+) density. Moreover, the S(++) vertical distribution is 25% more extended than that of S(+), indicating that the field-aligned S(++) kinetic temperature T(parallel to) is similar to50% higher. It also appears that the S(+) abundance dropped by at least a factor of 2 between the September-October 1999 and February 2000 epochs, while the other two sulfur ion abundances remained unchanged. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Colorado, Lab Astrophys & Space Phys, Boulder, CO 80309 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Herbert, F (reprint author), Univ Arizona, Lunar & Planetary Lab W, 901 Gould Simpson Bldg,1040 E 4th St, Tucson, AZ 85721 USA. EM herbert@vega.LPL.arizona.edu; nick.schneider@lasp.colorado.edu; amanda.hendrix@jpl.nasa.gov; bagenal@dosxx.colorado.edu NR 35 TC 6 Z9 6 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 3 PY 2003 VL 108 IS A5 BP 1 EP 14 AR 1167 DI 10.1029/2002JA009510 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 760VL UT WOS:000187855900001 ER PT J AU Mariano, AJ Chin, TM Ozgokmen, TM AF Mariano, AJ Chin, TM Ozgokmen, TM TI Stochastic boundary conditions for coastal flow modeling SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SEPARATION; VORTICITY; CURRENTS AB [1] Recent high-resolution radar data of surface velocity between the Florida Current and the coast allow us for the first time to deduce coastal boundary conditions for ocean models based on observations. A stochastic model is found to be a better choice for simulating properties of the observed vorticity than a model with deterministic boundary conditions. A stochastic model parameterizing boundary conditions is developed and embedded in a simple quasigeostrophic ocean model. Comparison of numerical simulations of western boundary flow with stochastic boundary conditions against simulations with traditional no-slip and free-slip conditions reveals significant differences in the formation of coherent mesoscale structures and the energetics of the western boundary current. Coherent structures such as dipoles and submesoscale vortices can be generated using stochastic boundary conditions. The boundary current variability becomes more energetic and "episodic'' than quasi-periodic circulation features in the simulations using the conventional boundary conditions. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Mariano, AJ (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. NR 11 TC 7 Z9 7 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 2 PY 2003 VL 30 IS 9 AR 1457 DI 10.1029/2003GL016972 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 678GN UT WOS:000182858300007 ER PT J AU Douglass, AR Schoeberl, MR Rood, RB Pawson, S AF Douglass, AR Schoeberl, MR Rood, RB Pawson, S TI Evaluation of transport in the lower tropical stratosphere in a global chemistry and transport model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE stratospheric transport; tropical barrier; age-of-air ID HALOGEN OCCULTATION EXPERIMENT; DATA ASSIMILATION; OZONE DEPLETION; CHLORINE ACTIVATION; 3-DIMENSIONAL MODEL; FORECAST BIAS; EARLY WINTER; AIRCRAFT; SIMULATION; SENSITIVITY AB [1] Off-line chemistry and transport models (CTMs) use meteorological information from a general circulation model (GCM) or from a data assimilation system (DAS) to calculate the evolution of stratospheric constituents. Here constituent fields from two CTM simulations are compared with each other and with observations from satellite, aircraft, and sondes to judge the realism of the tropical transport. One simulation uses winds from a GCM and the second uses winds from a DAS that has the same GCM at its core. A simulation using the GCM fields reproduces many observed features for O-3, CH4, and the age of air. The same comparisons for a simulation using DAS fields show rapid upward tropical transport and excessive mixing between the tropics and middle latitudes. The assimilation system changes the temperature and wind fields to produce consistency between a GCM forecast and observations, behaving like an additional forcing has been added to the equations of motion and possibly leading to the unrealistic transport produced by the DAS fields. These comparisons highlight aspects of the transport in the lower tropical stratosphere, and suggest that while a CTM driven by DAS fields provides good short-term simulations when event-by-event comparisons with observations are desired, a CTM driven by GCM fields may be more appropriate for long-term calculations such as required to assess the impact of changes in stratospheric composition. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RP Douglass, AR (reprint author), NASA, Goddard Space Flight Ctr, Code 916,Bldg 33,Room E323, Greenbelt, MD 20771 USA. EM Anne.R.Douglass@nasa.gov; Mark.R.Schoeberl@nasa.gov; Richard.B.Rood@nasa.gov; spawson@dao.gsfc.nasa.gov RI Douglass, Anne/D-4655-2012; Rood, Richard/C-5611-2008; Pawson, Steven/I-1865-2014 OI Rood, Richard/0000-0002-2310-4262; Pawson, Steven/0000-0003-0200-717X NR 63 TC 60 Z9 60 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 2 PY 2003 VL 108 IS D9 AR 4259 DI 10.1029/2002JD002696 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 678HL UT WOS:000182861100004 ER PT J AU Waugh, DW Hall, TM Haine, TWN AF Waugh, DW Hall, TM Haine, TWN TI Relationships among tracer ages SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE ocean tracers; ocean transport; tracer ages; transit time distributions ID EASTERN NORTH-ATLANTIC; DEEP-WATER RENEWAL; CARBON-TETRACHLORIDE; SULFUR-HEXAFLUORIDE; OCEAN VENTILATION; TRANSIENT TRACERS; ANTHROPOGENIC CO2; WEDDELL SEA; CHLOROFLUOROCARBONS; DISTRIBUTIONS AB [1] Measurements of chemical tracers whose spatial gradients are primarily due to the time dependence of sources and/or sinks are often used to define "tracer ages'' in an effort to diagnose transport. However, a major problem with interpreting these tracer ages is that different tracers can yield different ages, and at present, it is not clear what aspects of the transport are measured by the different tracers. We use the concept of a distribution of transit times to compare the timescales derived from different tracers, including CFCs, tritium-helium, and radioactive tracers. By performing a systematic study over a range of transit time distributions we examine under what conditions two tracers yield similar or different ages. It is shown that there can be significant differences in tracer ages and that in general, tracer ages are not fundamental timescales of the flow. Furthermore, even if ages from two tracers are similar these ages can be very different from the mean ( ideal) age or the age of a third tracer. It is also shown that significant temporal variations in tracer ages can occur for steady transport and that these changes are of similar magnitude to the changes in CFC and tritium-helium ages observed in the North Atlantic and North Pacific over the 1980s and 1990s. Accounting for the changes in tracer ages caused by steady transport is necessary before attributing changes in tracer ages to changes in transport. The possibility of using the differences in ages from different tracers to infer information about the transit time distribution is also examined. It is shown that two tracer ages can constrain the first two moments ( mean age and width) of the distribution, but how tightly these are constrained depends on the tracers used, the certainty of the age calculations, and the flow characteristics. C1 Johns Hopkins Univ, Dept Earth & Planetary Sci, Baltimore, MD 21218 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Waugh, DW (reprint author), Johns Hopkins Univ, Dept Earth & Planetary Sci, Baltimore, MD 21218 USA. RI Waugh, Darryn/K-3688-2016 OI Waugh, Darryn/0000-0001-7692-2798 NR 47 TC 92 Z9 93 U1 0 U2 19 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAY 2 PY 2003 VL 108 IS C5 AR 3138 DI 10.1029/2002JC001325 PG 16 WC Oceanography SC Oceanography GA 678JB UT WOS:000182862800003 ER PT J AU Esper, J Neeck, S Slavin, JA Leitner, J Wiscombe, W Bauer, FH AF Esper, J Neeck, S Slavin, JA Leitner, J Wiscombe, W Bauer, FH TI Nano/micro satellite constellations for Earth and Space Science SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 3rd IAA International Symposium on Small Satellites for Earth Observation CY APR 02-06, 2001 CL BERLIN, GERMANY SP IAA AB Spacecraft constellations are becoming a reality for NASA's Earth and Space science, with the first steps already under way in building the infrastructure and knowledge base required for their implementation. In this paper we provide updated information on nano/micro satellite constellation missions either within NASA's strategic plan or in the proposal stages. We will also present two examples of New Millennium Program technology missions that are today finding the solutions required to enable the constellations of the near and far-term future. Finally we will show what is being done in the area of Guidance, Navigation, and Control to facilitate the interconnectivity of constellations to act as single systems. (C) 2003 Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Esper, J (reprint author), Swales Aerosp, 5050 Powder Mill Rd, Beltsville, MD 20705 USA. RI Slavin, James/H-3170-2012; Wiscombe, Warren/D-4665-2012 OI Slavin, James/0000-0002-9206-724X; Wiscombe, Warren/0000-0001-6844-9849 NR 13 TC 13 Z9 14 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAY-JUN PY 2003 VL 52 IS 9-12 BP 785 EP 791 DI 10.1016/S0094-5765(03)00054-7 PG 7 WC Engineering, Aerospace SC Engineering GA 678GK UT WOS:000182858000017 ER PT J AU Alkalai, L AF Alkalai, L TI An overview of flight computer technologies for future NASA space exploration missions SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 3rd IAA International Symposium on Small Satellites for Earth Observation CY APR 02-06, 2001 CL BERLIN, GERMANY SP IAA C1 CALTECH, Jet Prop Lab, Ctr Integrated Space Microsyst, Pasadena, CA 91125 USA. RP Alkalai, L (reprint author), CALTECH, Jet Prop Lab, Ctr Integrated Space Microsyst, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 5 TC 1 Z9 3 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 MAY-JUN PY 2003 VL 52 IS 9-12 BP 857 EP + DI 10.1016/S0094-5765(03)00066-3 PG 11 WC Engineering, Aerospace SC Engineering GA 678GK UT WOS:000182858000027 ER PT J AU Deutsch, LJ AF Deutsch, LJ TI Inserting new technology into small missions SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 3rd IAA International Symposium on Small Satellites for Earth Observation CY APR 02-06, 2001 CL BERLIN, GERMANY SP IAA AB Part of what makes small missions small is that they have less money. Executing missions at low cost implies extensive use of cost sharing with other missions or use of existing solutions. However, in order to create many small missions, new technology must be developed, applied, and assimilated. These statements seem to contradict one another. Luckily, there are methods for creating new technology and inserting it into faster-better-cheaper (FBC) missions. NASA has invested in many processes for technology development and infusion. Each of these has had successes and has also uncovered areas for improvement. Understanding the technology lifecycle and how capabilities progress within it is critical to maintaining strong and successful technology development programs. (C) 2003 Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Technol Integrat Program Off, Pasadena, CA 91125 USA. RP Deutsch, LJ (reprint author), CALTECH, Jet Prop Lab, Technol Integrat Program Off, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 8 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 MAY-JUN PY 2003 VL 52 IS 9-12 BP 869 EP 873 DI 10.1016/S0094-5765(03)00067-5 PG 5 WC Engineering, Aerospace SC Engineering GA 678GK UT WOS:000182858000028 ER PT J AU Mueller, J Marrese, C Polk, J Yang, EH Green, A White, V Bame, D Chakraborty, I Vargo, S Reinicke, R AF Mueller, J Marrese, C Polk, J Yang, EH Green, A White, V Bame, D Chakraborty, I Vargo, S Reinicke, R TI An overview of MEMS-based micropropulsion developments at JPL SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 3rd IAA International Symposium on Small Satellites for Earth Observation CY APR 02-06, 2001 CL BERLIN, GERMANY SP IAA ID OPTIONS AB Development of MEMS (Microelectromechanical Systems) micropropulsion at the Jet Propulsion Laboratory (JPL) is reviewed. This includes a vapofizing liquid micro-thruster for ruicrospacecraft attitude control. a micro-ion engine for microspacecraft primary propulsion or large spacecraft fine attitude control, as well as several valve studies. including a solenoid valve studied in collaboration with Moog Space Products Division, and a piezoelectric micro-valve. The solenoid valve features much faster actuation (as little as 1.5 ms to open) than commercially available MEMS valves and showed no detectable leak (< 10(-4) sccs GN(2)) even after 1 million cycles. The solenoid valve weighs 7 gram and is about 1 cm(3). A micro-isolation valve, aimed at sealing propulsion systems at zero leak rates, was able to show burst pressures as high as 3,000 psi even though entirely machined from silicon and Pyrex. It could be actuated with energies as little as 0.1 mJ. (C) 2003 Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Moog Inc, Space Prod Div, Mission Viejo, CA 92691 USA. RP Mueller, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Yang, Eui-Hyeok/0000-0003-4893-1691 NR 15 TC 18 Z9 19 U1 1 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAY-JUN PY 2003 VL 52 IS 9-12 BP 881 EP 895 DI 10.1016/S0094-5765(03)00069-9 PG 15 WC Engineering, Aerospace SC Engineering GA 678GK UT WOS:000182858000030 ER PT J AU Merlin, PW AF Merlin, PW TI SR-71 Blackbird SO ADVANCED MATERIALS & PROCESSES LA English DT Article C1 Analyt Serv & Mat Inc, Dryden Flight Res Ctr, NASA, Edwards AFB, CA USA. RP Merlin, PW (reprint author), Analyt Serv & Mat Inc, Dryden Flight Res Ctr, NASA, Edwards AFB, CA USA. NR 0 TC 0 Z9 0 U1 2 U2 11 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 0882-7958 J9 ADV MATER PROCESS JI Adv. Mater. Process. PD MAY PY 2003 VL 161 IS 5 BP 27 EP 29 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA 677YE UT WOS:000182836300004 ER PT J AU Chandrasekhara, MS Wilder, MC AF Chandrasekhara, MS Wilder, MC TI Heat-flux gauge studies of compressible dynamic stall SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 40th AIAA Aerospace Sciences and Exhibit Conferene CY JAN 14-18, 2002 CL RENO, NEVADA SP Amer Inst Aeronaut & Astronaut ID AIRFOIL; FLOWFIELD AB Compressible dynamic stall was studied using 148 closely spaced heat-flux gauges distributed over the surface of an oscillating, 15.24-cm chord NACA 0012 airfoil. The study has revealed the various surface flow features of compressible dynamic stall. These include the rapid movement of the transition onset point over the airfoil upper surface on the upstroke with increasing angle of attack, the signature of the convecting dynamic-stall vortex, and the relaminarization of the reattaching shear layer on the downstroke. The imprint of a leading-edge shock has been captured for the first time in the surface flow signature. Even though compressible dynamic stall can originate from several causes depending upon flow conditions, the study led to the conclusion that a deterministic precursor of dynamic-stall onset is a sharp rise in the surface shear stress in the leading-edge adverse pressure gradient region, which is a common and singular How feature at all conditions tested. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. USN, Postgrad Sch, Monterey, CA 93943 USA. RP Chandrasekhara, MS (reprint author), NASA, Ames Res Ctr, MS 260-1, Moffett Field, CA 94035 USA. NR 13 TC 6 Z9 6 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 2003 VL 41 IS 5 BP 757 EP 762 DI 10.2514/2.2019 PG 6 WC Engineering, Aerospace SC Engineering GA 678LW UT WOS:000182869500001 ER PT J AU Caraballo, E Samimy, M Scott, J Narayanan, S DeBonis, J AF Caraballo, E Samimy, M Scott, J Narayanan, S DeBonis, J TI Application of proper orthogonal decomposition to a supersonic axisymmetric jet SO AIAA JOURNAL LA English DT Article ID COHERENT STRUCTURES; MIXING LAYER; PART 1; TURBULENCE; DYNAMICS; VELOCITY; FLOWS; FIELD AB Results are presented from the application of the snapshot proper orthogonal decomposition (POD) method to a spatiotemporal flowfield generated from large eddy simulations (LES) of a Mach 1.4 ideally expanded jet. This is part of ongoing research in the development and use of the POD method in conjunction with advanced laser-based optical measurements in high-speed flows. The POD application goal is twofold: to extract dynamically significant information on the large-scale coherent structures in a high-speed jet and to facilitate low-dimensional modeling of the jet. It was found that the spatial eigenmodes obtained using weakly correlated snapshots, but spanning tens of convective timescale and uncorrelated snapshots, are similar. It was also found that a short-duration temporally resolved LES data (simulating data obtainable from pulse burst laser-based measurements) could be used to calculate the time evolution coefficients of the eigenmodes. The use of a few modes (namely, 12) was sufficient for a reasonable reconstruction of the spatiotemporal flowfield. The use of POD with a vector norm instead of a scalar norm did reduce the energy captured in the first few modes and also changed their rank order, but did not substantially alter the reconstructed flow. In the early jet development region, the first and dominant mode was found to be axisymmetric, followed by either another axisymmetric or asymmetric (probably helical) mode, whereas higher modes in this region and all of the modes farther downstream were more complex and three-dimensional. The POD modes and their temporal coefficients obtained at various streamwise locations suggest that the large-scale jet structures undergo a process of disorganization near the end of potential core, followed by reorganization farther downstream. C1 Ohio State Univ, Gas Dynam & Turbulence Lab, Dept Mech Engn, Columbus, OH 43210 USA. Ohio State Univ, Aerosp & Aviat Dept, Columbus, OH 43210 USA. United Technol Res Ctr, Dept Syst, E Hartford, CT 06108 USA. NASA, John H Glenn Res Ctr Lewis Field, Nozzle Branch, Cleveland, OH 44135 USA. RP Caraballo, E (reprint author), Ohio State Univ, Gas Dynam & Turbulence Lab, Dept Mech Engn, Columbus, OH 43210 USA. NR 34 TC 9 Z9 9 U1 0 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 2003 VL 41 IS 5 BP 866 EP 877 DI 10.2514/2.2022 PG 12 WC Engineering, Aerospace SC Engineering GA 678LW UT WOS:000182869500012 ER PT J AU Liu, TS AF Liu, TS TI Pressure-correction method for low-speed pressure-sensitive paint measurements SO AIAA JOURNAL LA English DT Article AB An iterative pressure-correction method is developed that can be used to recover the incompressible pressure-coefficient distribution from pressure-sensitive Paint (PSP) results obtained at two suitably higher subsonic Mach numbers. The pressure-correction method provides an alternative approach to overcome the well-known difficulty of using PSP in low-speed,flows. For validation, this method is applied to flows over a circular cylinder, sphere, prolate spheroid, transonic body, and delta wing. Limitations and uncertainty of the pressure-correction method are discussed. C1 NASA, Langley Res Ctr, Model Syst Branch, Hampton, VA 23681 USA. RP Liu, TS (reprint author), NASA, Langley Res Ctr, Model Syst Branch, Mail Stop 238, Hampton, VA 23681 USA. NR 15 TC 3 Z9 3 U1 1 U2 6 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 2003 VL 41 IS 5 BP 906 EP 911 DI 10.2514/2.2026 PG 6 WC Engineering, Aerospace SC Engineering GA 678LW UT WOS:000182869500016 ER PT J AU Raju, IS Phillips, DR AF Raju, IS Phillips, DR TI Local coordinate approach in meshless local Petrov-Galerkin method for beam problems SO AIAA JOURNAL LA English DT Article C1 NASA, Langley Res Ctr, Struct & Mat Competency, Hampton, VA 23681 USA. George Washington Univ, Joint Inst Advancement Flight Sci, Hampton, VA 23681 USA. RP Raju, IS (reprint author), NASA, Langley Res Ctr, Struct & Mat Competency, Mail Stop 240, Hampton, VA 23681 USA. NR 8 TC 3 Z9 3 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 2003 VL 41 IS 5 BP 975 EP 978 DI 10.2514/2.2037 PG 4 WC Engineering, Aerospace SC Engineering GA 678LW UT WOS:000182869500026 ER PT J AU Dhillon, A Teske, A Dillon, J Stahl, DA Sogin, ML AF Dhillon, A Teske, A Dillon, J Stahl, DA Sogin, ML TI Molecular characterization of sulfate-reducing bacteria in the Guaymas Basin SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID SULFITE REDUCTASE GENES; HYDROTHERMAL VENT SITE; MICROBIAL DIVERSITY; ANAEROBIC OXIDATION; METHANE OXIDATION; MARINE SEDIMENT; SP-NOV; CALIFORNIA; GULF; MAT AB The Guaymas Basin (Gulf of California) is a hydrothermal vent site where thermal alteration of deposited planktonic and terrestrial organic matter forms petroliferous material which supports diverse sulfate-reducing bacteria. We explored the phylogenetic and functional diversity of the sulfate-reducing bacteria by characterizing PCR-amplified dissimilatory sulfite reductase (dsrAB) and 16S rRNA genes from the upper 4 cm of the Guaymas sediment. The dsrAB sequences revealed that there was a major clade closely related to the acetate-oxidizing delta-proteobacterial genus Desulfobacter and a clade of novel, deeply branching dsr sequences related to environmental dsr sequences from marine sediments in Aarhus Bay and Kysing Fjord (Denmark). Other dsr clones were affiliated with gram-positive thermophilic sulfate reducers (genus Desulfotomaculum) and the delta-proteobacterial species Desulforhabdus amnigena and Thermodesulforhabdus norvegica. Phylogenetic analysis of 16S rRNAs from the same environmental samples resulted in identification of four clones affiliated with Desulfobacterium niacini, a member of the acetate-oxidizing, nutritionally versatile genus Desulfobacterium, and one clone related to Desulfobacula toluolica and Desulfotignum balticum. Other bacterial 16S rRNA bacterial phylotypes were represented by non-sulfate reducers and uncultured lineages with unknown physiology, like OP9, OP8, as well as a group with no clear affiliation. In summary, analyses of both 16S rRNA and dsrAB clone libraries resulted in identification of members of the Desulfobacteriales in the Guaymas sediments. In addition, the dsrAB sequencing approach revealed a novel group of sulfate-reducing prokaryotes that could not be identified by 16S rRNA sequencing. C1 NASA, Biol Marine Lab, Josephine Bay Paul Ctr Comparat Mol Biol & Evolut, Astrobiol Inst, Woods Hole, MA 02543 USA. Woods Hole Oceanog Inst, Dept Biol, Woods Hole, MA 02543 USA. Univ Washington, Dept Civil & Environm Engn, Seattle, WA 98195 USA. RP Sogin, ML (reprint author), NASA, Biol Marine Lab, Josephine Bay Paul Ctr Comparat Mol Biol & Evolut, Astrobiol Inst, 7 MBL St, Woods Hole, MA 02543 USA. NR 51 TC 195 Z9 200 U1 2 U2 37 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 2003 VL 69 IS 5 BP 2765 EP 2772 DI 10.1128/AEM.69.5.2765-2772.2003 PG 8 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 677LD UT WOS:000182808300042 PM 12732547 ER PT J AU Saltikov, CW Cifuentes, A Venkateswaran, K Newman, DK AF Saltikov, CW Cifuentes, A Venkateswaran, K Newman, DK TI The ars detoxification system is advantageous but not required for As(V) respiration by the genetically tractable Shewanella species strain ANA-3 SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID BACTERIAL DISSIMILATORY REDUCTION; CHROMOSOMAL ARSENIC RESISTANCE; ESCHERICHIA-COLI; SP. NOV.; DESULFOTOMACULUM-AURIPIGMENTUM; CHRYSIOGENES-ARSENATIS; RESPIRING BACTERIUM; MONO LAKE; PUTREFACIENS; OXIDATION AB Arsenate [As(V); HAsO42-] respiration by bacteria is poorly understood at the molecular level largely due to a paucity of genetically tractable organisms with this metabolic capability. We report here the isolation of a new As(V)-respiring strain (ANA-3) that is phyllogenetically related to members of the genus Shewanella and that also provides a useful model system with which to explore the molecular basis of As(V) respiration. This gram-negative strain stoichiometrically couples the oxidation of lactate to acetate with the reduction of As(V) to arsenite [As(III); HAsO2]. The generation time and lactate molar growth yield (Y-lactate) are 2.8 h and 10.0 g of cells mol of lactate(-1), respectively, when it is grown anaerobically on lactate and As(V). ANA-3 uses a wide variety of terminal electron acceptors, including oxygen, soluble ferric iron, oxides of iron and manganese, nitrate, fumarate, the humic acid functional analog 2,6-anthraquinone disulfonate, and thiosulfate. ANA-3 also reduces As(V) to As(III) in the presence of oxygen and resists high concentrations of As(III) (up to 10 mM) when grown under either aerobic or anaerobic conditions. ANA-3 possesses an ars operon (arsDABC) that allows it to resist high levels of As (111); this operon also confers resistance to the As-sensitive strains Shewanella oneidensis MR-1 and Escherichia coli AW3110. When the gene encoding the As(111) efflux pump, arsB, is inactivated in ANA-3 by a polar mutation that also eliminates the expression of arsC, which encodes an As(V) reductase, the resulting As(Ill)-sensitive strain still respires As(V); however, the generation time and the Y-lactate value are two- and threefold lower, respectively, than those of the wild type. These results suggest that ArsB and ArsC may be useful for As(V)-respiring bacteria in environments where As concentrations are high, but that neither is required for respiration. C1 CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. Jet Prop Lab, Planetary Protect Technol, Pasadena, CA 91109 USA. RP Newman, DK (reprint author), CALTECH, Dept Geol & Planetary Sci, Mailstop 100-23, Pasadena, CA 91125 USA. NR 60 TC 93 Z9 100 U1 2 U2 31 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 2003 VL 69 IS 5 BP 2800 EP 2809 DI 10.1128/AEM.69.5.2800-2809.2003 PG 10 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 677LD UT WOS:000182808300046 PM 12732551 ER PT J AU Londry, KL Marais, DJD AF Londry, KL Marais, DJD TI Stable carbon isotope fractionation by sulfate-reducing bacteria SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID MONOXIDE DEHYDROGENASE PATHWAY; CITRIC-ACID CYCLE; DESULFOBACTERIUM-AUTOTROPHICUM; ACETATE OXIDATION; ENZYMES; CO2; ACETOXIDANS; EVOLUTION; RATIOS; MARINE AB Biogeochemical transformations occurring in the anoxic zones of stratified sedimentary microbial communities can profoundly influence the isotopic and organic signatures preserved in the fossil record. Accordingly, we have determined carbon isotope discrimination that is associated with both heterotrophic and lithotrophic growth of pure cultures of sulfate-reducing bacteria (SRB). For heterotrophic-growth experiments, substrate consumption was monitored to completion. Sealed vessels containing SRB cultures were harvested at different time intervals, and delta(13)C values were determined for gaseous CO2, organic substrates, and products such as biomass. For three of the four SRB, carbon isotope effects between the substrates, acetate or lactate and CO2, and the cell biomass were small, ranging from 0 to 2parts per thousand. However, for Desulfotomaculum acetoxidans, the carbon incorporated into biomass was isotopically heavier than the available substrates by 8 to 9parts per thousand. SRB grown lithoautotrophically consumed less than 3% of the available CO2 and exhibited substantial discrimination (calculated as isotope fractionation factors [alpha]), as follows: for Desulfobacterium autotrophicum, alpha values ranged from 1.0100 to 1.0123; for Desulfobacter hydrogenophilus, the alpha value was 0.0138, and for Desulfotomaculum acetoxidans, the alpha value was 1.0310. Mixotrophic growth of Desulfovibrio desulfuricans on acetate and CO2 resulted in biomass with a delta(13)C composition intermediate to that of the substrates. The extent of fractionation depended on which enzymatic pathways were used, the direction in which the pathways operated, and the growth rate, but fractionation was not dependent on the growth phase. To the extent that environmental conditions affect the availability of organic substrates (e.g., acetate) and reducing power (e.g., H-2), ecological forces can also influence carbon isotope discrimination by SRB. C1 NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. RP Londry, KL (reprint author), Univ Manitoba, Dept Microbiol, Winnipeg, MB R3T 2N2, Canada. NR 28 TC 63 Z9 66 U1 2 U2 21 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 2003 VL 69 IS 5 BP 2942 EP 2949 DI 10.1128/AEM.69.5.2942-2949.2003 PG 8 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 677LD UT WOS:000182808300065 PM 12732570 ER PT J AU Lien, MC Remington, RW AF Lien, MC Remington, RW TI The limits of attention: Temporal constraints in human information processing. SO APPLIED COGNITIVE PSYCHOLOGY LA English DT Book Review C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Lien, MC (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 1 TC 0 Z9 0 U1 0 U2 2 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0888-4080 J9 APPL COGNITIVE PSYCH JI Appl. Cogn. Psychol. PD MAY PY 2003 VL 17 IS 4 BP 495 EP 496 DI 10.1002/acp.884 PG 2 WC Psychology, Experimental SC Psychology GA 676RK UT WOS:000182765900007 ER PT J AU Evans, AS Becklin, EE Scoville, NZ Neugebauer, G Soifer, BT Matthews, K Ressler, M Werner, M Rieke, M AF Evans, AS Becklin, EE Scoville, NZ Neugebauer, G Soifer, BT Matthews, K Ressler, M Werner, M Rieke, M TI The compact nucleus of the deep silicate absorption galaxy NGC 4418 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 4418) ID LUMINOUS INFRARED GALAXIES; IRAS GALAXIES; NGC-4418; MICRONS; SAMPLE AB High-resolution Hubble Space Telescope (HST) near-infrared and Keck mid-infrared images of the heavily extinguished infrared-luminous galaxy NGC 4418 are presented. These data make it possible to observe the imbedded near-infrared structure on scales of 10-20 pc and to constrain the size of the mid-infrared-emitting region. The 1.1-2.2 mum data of NGC 4418 show no clear evidence of nuclear star clusters or of a reddened active galactic nucleus. Instead, the nucleus of the galaxy consists of a similar to100-200 pc linear structure with fainter structures extending radially outward. The near-infrared colors of the linear feature are consistent with a 10-300 Myr starburst suffering moderate levels (a few magnitudes) of visual extinction. At 7.9-24.5 mum NGC 4418 has estimated size upper limits in the range of 30-80 pc. These dimensions are consistent with the highest-resolution radio observations obtained to date of NGC 4418, as well as the size of 50-70 pc expected for a blackbody with a temperature derived from the 25, 60, and 100 mum flux densities of the galaxy. Further, a spectral energy distribution constructed from the multiwavelength mid-infrared observations shows the strong silicate absorption feature at 10 mum, consistent with previous mid-infrared observations of NGC 4418. An infrared surface brightness of similar to2.1 x 10(13) L-. kpc(-2) is derived for NGC 4418. Such a value, though consistent with the surface brightness of warm ultraluminous infrared galaxies [L-IR(8-1000 mum) greater than or equal to 10(12) L-.], such as IRAS 05189-2524 and IRAS 08572+3915, is not large enough to distinguish NGC 4418 as a galaxy powered by an active galactic nucleus, as opposed to a lower surface brightness starburst. C1 SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. CALTECH, Palomar Observ, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Evans, AS (reprint author), SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. NR 27 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 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2003 VL 125 IS 5 BP 2341 EP 2347 DI 10.1086/374234 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 669VU UT WOS:000182371800005 ER PT J AU Miller, NA Owen, FN Hill, J AF Miller, NA Owen, FN Hill, J TI A comprehensive radio and optical study of Abell 2256: Activity from an infalling group SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : clusters : individual (Abell 2256); galaxies : evolution; radio continuum ID EMISSION-LINE SPECTRA; X-RAY; STAR-FORMATION; CLUSTER ABELL-2256; RICH CLUSTERS; COMA CLUSTER; GALAXIES; SAMPLE; CLASSIFICATION; SUBSTRUCTURE AB Abell 2256 is a nearby (z approximate to 0.06), rich cluster of galaxies with fascinating observed properties across a range of wavelengths. Long believed to represent a cluster merger, recent X-ray and optical results have suggested that in addition to the primary cluster and subcluster there is evidence for a third, poorer system. We present wide-field high-sensitivity 1.4 GHz VLA radio observations of Abell 2256 in conjunction with optical imaging and additional spectroscopy. Over 40 cluster radio galaxies are identified, with optical spectroscopy indicating the emission source ( star formation or active galactic nucleus) for most of them. While the overall fraction of galaxies exhibiting radio emission is consistent with a large sample of other nearby clusters, we find an increase in the activity level of galaxies belonging to the third system (hereafter "the Group''). Specifically, the Group has relatively more star formation than both the primary cluster and main subcluster. The position of the Group is also coincident with the observed cluster radio relic. We suggest that the Group recently (similar to0.3 Gyr) merged with the primary cluster and that this merger, not the ongoing merger of the primary and the main subcluster, might be responsible for many of the unusual radio properties of Abell 2256. Furthermore, the greater star formation activity of the Group suggests that the infall of groups is an important driver of galaxy evolution in clusters. C1 NASA, Goddard Space Flight Ctr, UV Opt Branch, Greenbelt, MD 20771 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Univ Arizona, Large Binocular Telescope Observ, Tucson, AZ 85721 USA. RP Miller, NA (reprint author), NASA, Goddard Space Flight Ctr, UV Opt Branch, Code 681, Greenbelt, MD 20771 USA. NR 58 TC 25 Z9 25 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 2003 VL 125 IS 5 BP 2393 EP 2410 DI 10.1086/374628 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 669VU UT WOS:000182371800009 ER PT J AU Condon, JJ Cotton, WD Yin, QF Shupe, DL Storrie-Lombardi, LJ Helou, G Soifer, BT Werner, MW AF Condon, JJ Cotton, WD Yin, QF Shupe, DL Storrie-Lombardi, LJ Helou, G Soifer, BT Werner, MW TI The SIRTF first-look survey. I. VLA image and source catalog SO ASTRONOMICAL JOURNAL LA English DT Article DE catalogs; galaxies : active; galaxies : starburst; infrared radiation; radio continuum; surveys AB The First-Look Survey (FLS) of the Space Infrared Telescope Facility (SIRTF) will cover about 5 deg(2) centered on J2000.0 alpha = 17(h)18(m), delta = + 59degrees30' in order to characterize the extragalactic infrared sky 2 orders of magnitude deeper than the IRAS survey. We expect that most of the FLS far-infrared (lambda = 160, 70, and 24 mum) sources will be star-forming galaxies obeying the very tight far-infrared/radio correlation and will be continuum radio sources with flux densities S greater than or similar to 100 muJy at nu = 1.4 GHz. Conversely, radio sources stronger than 100 muJy are usually powered by star-forming galaxies, plus some active galactic nuclei, and most should be detectable by the SIRTF FLS. Thus, a sensitive radio survey can be used to select and identify most of the SIRTF FLS source population before launch. We used the B configuration of the VLA to make an image of the FLS area at nu = 1.4 GHz with sigma approximate to 23 muJy beam(-1) rms fluctuations, theta = 5."0 resolution, and sigma(alpha) approximate to sigma(delta) less than or similar to0."5 rms uncertainties in right ascension and declination. The resulting radio image and catalog of 3565 radio components with peak flux densities S-p greater than or equal to 5sigma = 115 muJy beam(-1) have been released via the Web to expedite follow-up optical identification and spectroscopy. C1 Natl Radio Astron Observ, Charlottesville, VA 22903 USA. CALTECH, SIRTF Sci Ctr, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Condon, JJ (reprint author), Natl Radio Astron Observ, 520 Edgemont Rd, Charlottesville, VA 22903 USA. NR 9 TC 78 Z9 78 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 2003 VL 125 IS 5 BP 2411 EP 2426 DI 10.1086/374633 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 669VU UT WOS:000182371800010 ER PT J AU Miller, NA Owen, FN AF Miller, NA Owen, FN TI Abell 2255: Increased star formation and AGN activity in a cluster-cluster merger SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : clusters : individual (Abell 2255); galaxies : evolution; radio continuum ID 20-CM VLA SURVEY; COMA CLUSTER; GIANT GALAXIES; DISTANT CLUSTERS; SKY SURVEY; RADIO; EVOLUTION; POPULATIONS; EMISSION; SAMPLE AB Deep VLA 1.4 GHz radio continuum imaging of Abell 2255 is presented. This cluster is among the better nearby candidates for rich cluster-cluster merger systems, with evidence including an elongated X-ray morphology, the presence of a radio halo, and substructure present in its galaxy distribution. Our radio observations reach an rms sensitivity of similar to40 muJy beam(-1), enabling us to detect (at 5 sigma) star formation rates as low as 1.4 M-. yr(-1) from the center of the cluster out to a radial distance of 3 h(75)(-1) Mpc. The radio data are complemented by optical imaging and a large spectroscopic database, allowing us to separate all galaxies with M-Rc less than or equal to - 20 into cluster members and foreground/background galaxies. The spectra are also used to associate the galaxies' radio emission with either star formation or active galactic nuclei (AGNs). We compare the resulting cluster radio galaxy population with those of 19 other nearby Abell clusters and find strong evidence for an increase in the frequency of radio galaxies in Abell 2255. This increase is seen in two separate types of galaxies: powerful radio AGNs and optically faint star-forming galaxies. The optical spectra of the latter often indicate current or recent starbursts, and these galaxies appear to be distributed along an axis perpendicular to the probable merger axis. We assess these factors in light of models of galaxy evolution and suggest that the cluster-cluster merger is responsible for triggering galaxy activity in Abell 2255. C1 NASA, Goddard Space Flight Ctr, UV Opt Branch, Greenbelt, MD 20771 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. RP Miller, NA (reprint author), NASA, Goddard Space Flight Ctr, UV Opt Branch, Code 681, Greenbelt, MD 20771 USA. NR 74 TC 54 Z9 55 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 2003 VL 125 IS 5 BP 2427 EP 2446 DI 10.1086/374767 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 669VU UT WOS:000182371800011 ER PT J AU Stephens, AW Frogel, JA DePoy, DL Freedman, W Gallart, C Jablonka, P Renzini, A Rich, RM Davies, R AF Stephens, AW Frogel, JA DePoy, DL Freedman, W Gallart, C Jablonka, P Renzini, A Rich, RM Davies, R TI The stellar content of the bulge of M31 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual (M31=NGC 224) ID GIANT BRANCH STARS; LUMINOSITY FUNCTION; GALACTIC BULGE; BAADES WINDOW; GLOBULAR-CLUSTERS; FIELDS; METALLICITY; POPULATION; GALAXIES; HALO AB We analyze the stellar populations present in M31 by using nine sets of adjacent Hubble Space Telescope NICMOS camera 1 and 2 fields with galactocentric distances ranging from 2' to 20'. These infrared observations provide some of the highest spatial resolution measurements of M31 to date; our data place tight constraints on the maximum luminosities of stars in the bulge of M31. The tip of the red giant branch is clearly visible at M-bol similar to -3.8, and the tip of the asymptotic giant branch (AGB) extends to M-bol similar to -5. This AGB peak luminosity is significantly fainter than previously claimed; through direct comparisons and simulations we show that previous measurements were affected by image blending. We do observe field-to-field variations in the luminosity functions, but simulations show that these differences can be produced by blending in the higher surface brightness fields. We conclude that the red giant branch of the bulge of M31 is not measurably different from that of the bulge of the Milky Way. We also find an unusually high number of bright bluish stars (7.3 arcmin(-2)), which appear to be Galactic foreground stars. C1 Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago 22, Chile. Princeton Univ Observ, Princeton, NJ 08544 USA. NASA Headquarters, Off Space Sci, Washington, DC 20546 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Carnegie Observ, Pasadena, CA 91101 USA. Inst Astrofis Canarias, E-38200 San Cristobal la Laguna, Spain. Observ Paris, F-92195 Meudon, France. European So Observ, D-85748 Garching, Germany. Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA. Univ Durham, Dept Phys, Durham DH1 3LE, England. RP Stephens, AW (reprint author), Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Casilla 306, Santiago 22, Chile. NR 34 TC 41 Z9 41 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 2003 VL 125 IS 5 BP 2473 EP 2493 DI 10.1086/374570 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 669VU UT WOS:000182371800014 ER PT J AU Beichman, CA Cutri, R Jarrett, T Stiening, R Skrutskie, M AF Beichman, CA Cutri, R Jarrett, T Stiening, R Skrutskie, M TI A deep 2MASS survey of the Lockman Hole SO ASTRONOMICAL JOURNAL LA English DT Article DE infrared radiation; quasars : general; stars : low-mass, brown dwarfs; surveys ID PROTOTYPE SURVEY; GALAXY COUNTS; DISTRIBUTIONS; REDSHIFT; CATALOG; QUASAR; DWARFS; MAPS AB We have carried out a survey of the Lockman Hole covering over 24 deg(2) using the Two Micron All Sky Survey (2MASS) observing system in a special mode that reaches roughly 1 mag deeper than the nominal 2MASS survey. The resultant point-source catalog reaches to approximately (J, H, K-s) < ( 17.8, 16.5, 16.0) mag with completeness and reliability in excess of 90%-95% at the faintest levels. These data will be useful in identifying sources in SIRTF surveys of this area. We have cataloged 69,115 objects, almost twice as many as in the nominal 2MASS survey of this region. The sample includes a large number of potential new active galaxies, as well as a T dwarf candidate. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM chas@pop.jpl.nasa.gov NR 34 TC 16 Z9 16 U1 0 U2 1 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 MAY PY 2003 VL 125 IS 5 BP 2521 EP 2530 DI 10.1086/374770 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 669VU UT WOS:000182371800017 ER PT J AU Rebull, LM Cole, DM Stapelfeldt, KR Werner, MW AF Rebull, LM Cole, DM Stapelfeldt, KR Werner, MW TI High-resolution mid-infrared observations of very young stellar objects in NGC 1333 SO ASTRONOMICAL JOURNAL LA English DT Article DE open clusters and associations : individual (NGC 1333); stars : formation; stars : pre-main-sequence ID HERBIG-HARO OBJECTS; IR IMAGING PHOTOMETRY; MOLECULAR CLOUD; NGC-1333 IRAS-4; STARS; ASSOCIATIONS; VARIABILITY; POPULATION; NEBULA; REGION AB We observed 22 young stellar objects in the region of NGC 1333 by using the mid-infrared camera MIRLIN. NGC 1333 (in the Perseus OB2 molecular cloud complex) is a relatively well studied region, but not at high spatial resolution in the mid-infrared. MIRLIN's 0."5 spatial resolution allows us to look for source extension and multiplicity and to place new constraints on spectral energy distributions. We report here new detections of eight objects at mid-IR wavelengths. We find one object, SVS 12, that may be extended or multiple, and we confirm multiplicity in SVS 16. We find a new companion to ASR 107. We are able to classify six objects as Class I, flat spectrum, or II, place strong classification constraints on two objects, and more loosely restrict the classification of eight more objects. These observations will aid in interpretation of planned SIRTF observations of this cluster. C1 CALTECH, SIRTF Sci Ctr, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Natl Res Council, Resident Res Associate, Pasadena, CA 91109 USA. RP Rebull, LM (reprint author), CALTECH, SIRTF Sci Ctr, 220-6,1200 E Calif Blvd, Pasadena, CA 91125 USA. RI Stapelfeldt, Karl/D-2721-2012; OI Rebull, Luisa/0000-0001-6381-515X NR 40 TC 7 Z9 7 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 2003 VL 125 IS 5 BP 2568 EP 2583 DI 10.1086/374769 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 669VU UT WOS:000182371800022 ER PT J AU Pritzl, BJ Smith, HA Catelan, M Sweigart, AV AF Pritzl, BJ Smith, HA Catelan, M Sweigart, AV TI Variable stars in the unusual, metal-rich, globular cluster NGC 6441 (vol 122, pg 2600, 2001) SO ASTRONOMICAL JOURNAL LA English DT Correction C1 Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pritzl, BJ (reprint author), Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. NR 1 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 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2003 VL 125 IS 5 BP 2750 EP 2750 DI 10.1086/374634 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 669VU UT WOS:000182371800036 ER PT J AU Pritzl, BJ Smith, HA Catelan, M Sweigart, AV AF Pritzl, BJ Smith, HA Catelan, M Sweigart, AV TI Variable stars in the unusual, metal-rich globular cluster NGC 6388 (vol 124, pg 949, 2002) SO ASTRONOMICAL JOURNAL LA English DT Correction C1 Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago, Chile. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pritzl, BJ (reprint author), Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. NR 1 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 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2003 VL 125 IS 5 BP 2752 EP 2752 DI 10.1086/374787 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 669VU UT WOS:000182371800038 ER PT J AU Bautista, MA Mendoza, C Kallman, TR Palmeri, P AF Bautista, MA Mendoza, C Kallman, TR Palmeri, P TI Atomic data for the K-vacancy states of Fe XXIV SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE atomic data; atomic processes; line : formation; X-rays : general ID DIELECTRONIC SATELLITE SPECTRA; HIGH-RESOLUTION MEASUREMENTS; INNER-SHELL TRANSITIONS; R-MATRIX APPROACH; LI-LIKE IONS; CROSS-SECTIONS; ISOELECTRONIC SEQUENCE; COLLISION STRENGTHS; ELECTRON-SCATTERING; MULTIPLE IONIZATION AB As part of a project to compute atomic data for the spectral modeling of iron K lines, we report calculations and comparisons of atomic data for K-vacancy states in Fe XXIV. The data sets include: (i) energy levels, line wavelengths, radiative and Auger rates; (ii) inner-shell electron impact excitation rates and (iii) fine structure inner-shell photoabsorption cross sections. The calculations of energy levels and radiative and Auger rates have involved a detailed study of orbital representations, core relaxation, configuration interaction, relativistic corrections, cancellation effects and semi-empirical corrections. It is shown that a formal treatment of the Breit interaction is essential to render the important magnetic correlations that take part in the decay pathways of this ion. As a result, the accuracy of the present A-values is estimated at 10% while that of the Auger rates at 15%. The calculations of collisional excitation and photoabsorption cross sections take into account the effects of radiation and spectator Auger dampings. In collisional excitation, these effects cause significant attenuation of resonances leading to a good agreement with a simpler method where resonances are excluded. In photoabsorption, resonances converging to the K thresholds display symmetric profiles of constant width that causes edge smearing. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Inst Venezolano Invest Cient, Ctr Fis, A-1020 Vienna, Austria. RP Kallman, TR (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 61 TC 41 Z9 41 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 2003 VL 403 IS 1 BP 339 EP 355 DI 10.1051/0004-6361:20030367 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 673CC UT WOS:000182561100036 ER PT J AU Reeves, JN Watson, D Osborne, JP Pounds, KA O'Brien, PT AF Reeves, JN Watson, D Osborne, JP Pounds, KA O'Brien, PT TI Soft X-ray emission lines in the afterglow spectrum of GRB 011211: A detailed XMM-Newton analysis SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma rays : bursts; supernovae : general; X-rays : general ID PARAMETER-ESTIMATION; LIKELIHOOD RATIO; BURSTS; GRB-990705; ASTRONOMY; EJECTA; EDGE AB We report on an XMM-Newton observation of the X-ray afterglow of the Gamma Ray Burst GRB 011211, originally detected by Beppo-SAX on 11th December 2001. The early afterglow spectrum obtained by XMM-Newton, observed 11 hours after the initial burst, appeared to reveal decaying H-like Kalpha emission lines of Mg, Si, S, Ar and Ca, arising in enriched material with an outflow velocity of order 0.1c (Reeves et al. 2002). This was attributed to matter ejected from a massive stellar progenitor occurring shortly before the burst itself. Here, we present a detailed re-analysis of the XMM-Newton EPIC observations of GRB 011211. In particular, we show that the detection of the soft X-ray line emission appears robust, regardless of detector background, calibration, spectral binning, or the spectral model that is assumed. We demonstrate that thermal emission, from an optically thin plasma, is the most plausible model that can account for the soft X-ray emission, which appears to be the case for at least two burst afterglow spectra observed by XMM-Newton. The X-ray spectrum of GRB 011211 appears to evolve with time after the first 10 ks of the XMM-Newton observation as the Si and S emission lines are only detected during the first 10 ks of observation. The observations suggest that thermal emission is present during the early afterglow spectrum, whilst a power-law component dominates the latter stages. Finally we estimate the mass of the ejected material in GRB 011211 to be of the order 4-20 solar masses. C1 Univ Leicester, Dept Phys & Astron, Xray & Observat Astron Grp, Leicester LE1 7RH, Leics, England. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. RP Univ Leicester, Dept Phys & Astron, Xray & Observat Astron Grp, Univ Rd, Leicester LE1 7RH, Leics, England. EM wat@star.le.ac.uk RI Watson, Darach/E-4521-2015 OI Watson, Darach/0000-0002-4465-8264 NR 36 TC 43 Z9 43 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2003 VL 403 IS 2 BP 463 EP 472 DI 10.1051/0004-6361:20030204 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 675DY UT WOS:000182678800012 ER PT J AU Dahlem, M Ehle, M Jansen, F Heckman, TM Weaver, KA Strickland, DK AF Dahlem, M Ehle, M Jansen, F Heckman, TM Weaver, KA Strickland, DK TI The quest for hot gas in the halo of NGC1511 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : individual : NGC1511; galaxies : general; galaxies : ISM; galaxies : starburst ID XMM-NEWTON OBSERVATIONS; ROSAT PSPC OBSERVATIONS; NEARBY SPIRAL GALAXIES; X-RAY MINISURVEY; EDGE-ON; STARBURST GALAXIES; GASEOUS HALOS; EMISSION; SUPERWINDS; NGC-253 AB XMM-Newton observations of the starburst galaxy NGC 1511 reveal the presence of a previously unknown extended hot gaseous phase of its ISM, which partly extends out of the disk plane. The emission distribution is asymmetric, being brightest in the eastern half of the galaxy, where also radio continuum observations suggest the highest level of star formation. Spectral analysis of the integral 0.2-12 keV X-ray emission from NGC1511 indicates a complex emission composition. A model comprising a power law plus thermal plasma component, both absorbed by foreground gas, cannot explain all details of the observed spectrum, requiring a third spectral component to be added. This component can be a second thermal plasma, but other spectral models can be fitted as well. Its X-ray properties characterize NGC 1511 as a starburst galaxy. The X-ray-to-infrared luminosity ratio is consistent with this result. Together with the X-ray data, XMM-Newton obtained UV images of NGC 1511, tracing massive stars heating the ambient gas, which is then seen in Halpha emission. UV, Halpha and near-infrared imagery suggest that NGC 1511 is disturbed, most likely by its two small companions, NGC 1511a and NGC 1511b. C1 European So Observ, Santiago 19, Chile. XMM Newton Sci Operat Ctr, Madrid 28080, Spain. European Space Agcy, ESTEC, Res & Sci Support Dept, Sci Operat & Data Syst Div, NL-2200 AG Noordwijk, Netherlands. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Paul Wild Observ, Australia Telescope Natl Facil, Locked Bag 194, Narrabri, NSW 2390, Australia. EM Michael.Dahlem@csiro.au NR 35 TC 10 Z9 10 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2003 VL 403 IS 2 BP 547 EP 553 DI 10.1051/0004-6361:20030381 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 675DY UT WOS:000182678800020 ER PT J AU Spoon, HWW Moorwood, AFM Pontoppidan, KM Cami, J Kregel, M Lutz, D Tielens, AGGM AF Spoon, HWW Moorwood, AFM Pontoppidan, KM Cami, J Kregel, M Lutz, D Tielens, AGGM TI Detection of strongly processed ice in the central starburst of NGC 4945? SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : individual : NGC4945; galaxies : ISM; galaxies : nuclei; galaxies : starburst; infrared : galaxies ID MICRON KECK/NIRSPEC SPECTRA; LINE-OF-SIGHT; HIGH-RESOLUTION; GALAXY NGC-4945; GALACTIC-CENTER; INFRARED-SPECTROSCOPY; ABSORPTION FEATURES; INTERSTELLAR ICES; SEYFERT ACTIVITY; GRAIN MANTLES AB The composition of ice grains provides an important tool for the study of the molecular environment of star forming regions. Using ISAAC at the VLT to obtain spectra around 4.65 mum we have detected for the first time "XCN" and CO ice in an extragalactic environment: the nuclear region of the nearby dusty starburst/AGN galaxy NGC4945. The profile of the solid CO band reveals the importance of thermal processing of the ice while the prominence of the XCN band attests to the importance of energetic processing of the ice by FUV radiation and/or energetic particles. In analogy to the processing of ices by embedded protostars in our Galaxy, we attribute the processing of the ices in the center of NGC4945 to ongoing massive star formation. Our M-band spectrum also shows strong HI Pfbeta and H-2 0-0 S( 9) line emission and gas phase CO absorption lines. The HI, H2, PAH, gas phase CO and the ices seem to be embedded in a rotating molecular disk which is undergoing vigorous star formation. Recently, strong OCN- absorption has been detected in the spectrum of the Galactic center star GC: IRS 19. The most likely environment for the OCN- absorption is the strongly UV-exposed GC molecular ring. The presence of processed ice in the center of NGC4945 and our Galactic center leads us to believe that processed ice may be a common characteristic of dense molecular material in star forming galactic nuclei. C1 Univ Groningen, Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. European So Observ, D-85748 Garching, Germany. Leiden Observ, NL-2300 RA Leiden, Netherlands. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. SRON, NL-9700 AV Groningen, Netherlands. RP Spoon, HWW (reprint author), Univ Groningen, Kapteyn Astron Inst, POB 800, NL-9700 AV Groningen, Netherlands. EM spoon@astro.rug.nl NR 44 TC 31 Z9 31 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 2003 VL 402 IS 2 BP 499 EP 507 DI 10.1051/0004-6361:20030290 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 667HD UT WOS:000182224500012 ER PT J AU Feng, H Chen, Y Zhang, SN Lu, FJ Li, TP AF Feng, H Chen, Y Zhang, SN Lu, FJ Li, TP TI Improving the spatial resolution of XMM-Newton EPIC images by direct demodulation technique SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE techniques : high angular resolution; techniques : image processing AB We have applied the direct demodulation technique to XMM-Newton EPIC images to achieve a higher spatial resolution; the restored images are compared with Chandra images. With the improved images we can extract spectra of fine structures in XMM-Newton data. C1 Tsing Hua Univ, Dept Engn Phys, Beijing 100084, Peoples R China. CAS, Inst High Energy Phys, Lab Particle Astrophys, Beijing 100039, Peoples R China. Tsing Hua Univ, Dept Phys, Beijing 100084, Peoples R China. Tsing Hua Univ, Ctr Astrophys, Beijing 100084, Peoples R China. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Feng, H (reprint author), Tsing Hua Univ, Dept Engn Phys, Beijing 100084, Peoples R China. NR 14 TC 5 Z9 5 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 2003 VL 402 IS 3 BP 1151 EP 1155 DI 10.1051/0004-6361:20030324 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 671EH UT WOS:000182452000041 ER PT J AU Frisk, U Hagstrom, M Ala-Laurinaho, J Andersson, S Berges, JC Chabaud, JP Dahlgren, M Emrich, A Floren, G Florin, G Fredrixon, M Gaier, T Haas, R Hirvonen, T Hjalmarsson, A Jakobsson, B Jukkala, P Kildal, PS Kollberg, E Lassing, J Lecacheux, A Lehikoinen, P Lehto, A Mallat, J Marty, C Michet, D Narbonne, J Nexon, M Olberg, M Olofsson, AOH Olofsson, G Origne, A Petersson, M Piirone, P Pouliquen, D Ristorcelli, I Rosolen, C Rouaix, G Raisanen, AV Serra, G Sjoberg, F Stenmark, L Torchinsky, S Tuovinen, J Ullberg, C Vinterhav, E Wadefalk, N Zirath, H Zimmermann, P Zimmermann, R AF Frisk, U Hagstrom, M Ala-Laurinaho, J Andersson, S Berges, JC Chabaud, JP Dahlgren, M Emrich, A Floren, G Florin, G Fredrixon, M Gaier, T Haas, R Hirvonen, T Hjalmarsson, A Jakobsson, B Jukkala, P Kildal, PS Kollberg, E Lassing, J Lecacheux, A Lehikoinen, P Lehto, A Mallat, J Marty, C Michet, D Narbonne, J Nexon, M Olberg, M Olofsson, AOH Olofsson, G Origne, A Petersson, M Piirone, P Pouliquen, D Ristorcelli, I Rosolen, C Rouaix, G Raisanen, AV Serra, G Sjoberg, F Stenmark, L Torchinsky, S Tuovinen, J Ullberg, C Vinterhav, E Wadefalk, N Zirath, H Zimmermann, P Zimmermann, R TI The Odin satellite - I. Radiometer design and test SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE space vehicles; space vehicles : instruments; telescopes; techniques : spectroscopic ID SPACE APPLICATION; 119 GHZ; SPECTROMETERS; MILLIMETER; ASTRONOMY AB The Sub-millimetre and Millimetre Radiometer (SMR) is the main instrument on the Swedish, Canadian, Finnish and French spacecraft Odin. It consists of a 1.1 metre diameter telescope with four tuneable heterodyne receivers covering the ranges 486-504 GHz and 541-581 GHz, and one fixed at 118.75 GHz together with backends that provide spectral resolution from 150 kHz to 1 MHz. This Letter describes the Odin radiometer, its operation and performance with the data processing and calibration described in Paper II. C1 Swedish Space Corp, S-17104 Solna, Sweden. Chalmers Univ Technol, Onsala Space Observ, S-43992 Onsala, Sweden. Helsinki Univ Technol, Radio Lab, Espoo 02015, Finland. Omnisys Instruments, S-42130 Gothenburg, Sweden. CNRS, LAM, Observ Astron Marseille Provence, F-13376 Marseille 12, France. CNRS, Ctr Etud Spatiale Rayonnements, F-31028 Toulouse, France. SCFAB, Stockholm Observ, S-10691 Stockholm, Sweden. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. TRW Co Inc, Redondo Beach, CA 90278 USA. Ylinen Elect Ltd, Kauniainen 02700, Finland. Chalmers Univ Technol, S-41296 Gothenburg, Sweden. Observ Paris, Dept ARPEGES, F-92195 Meudon, France. Saab Ericsson Space, S-40515 Gothenburg, Sweden. ACR, S-61900 Trosa, Sweden. Canadian Space Agcy, Ottawa, ON K1L 8E3, Canada. Radiometer Phys, D-5309 Meckenheim, Germany. RP Frisk, U (reprint author), Swedish Space Corp, Box 4207, S-17104 Solna, Sweden. RI Raisanen, Antti/G-2405-2013; Ala-Laurinaho, Juha/M-4538-2016 NR 21 TC 91 Z9 92 U1 0 U2 9 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 2003 VL 402 IS 3 BP L27 EP L34 DI 10.1051/0004-6361:20030335 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 671EH UT WOS:000182452000002 ER PT J AU Abazajian, KN AF Abazajian, KN TI Telling three from four neutrinos with cosmology SO ASTROPARTICLE PHYSICS LA English DT Article ID BIG-BANG NUCLEOSYNTHESIS; HYDROGEN ABUNDANCE RATIO; DEUTERIUM ABUNDANCE; EARLY UNIVERSE; PRIMORDIAL ABUNDANCE; STERILE NEUTRINOS; FLAVOR OSCILLATIONS; ANTIMATTER DOMAINS; BARYON DENSITY; QSO AB New results, namely the independent determination of the deuterium abundance in several quasar absorption systems, and the complementary determination of the cosmological baryon density by observations of anisotropies in the cosmic microwave background (CMB), allow for a reevaluation of the constraints on the relativistic particle content of the Universe at primordial nucleosynthesis. Expressed in terms of the neutrino energy density, we find 1.7 < N-v < 3.5 (95% CL). In particular, we show that phenomenological four neutrino models including a sterile state (not participating in SU(2)(L) x U(1)(Y) interactions) unavoidably thermalize a fourth neutrino, and are highly disfavored in the standard minimal model of primordial nucleosynthesis, if the systematic uncertainty in the primordial helium abundance is small. We describe plausible extensions of the minimal model which evade this constraint. (C) 2002 Elsevier Science B.V. All rights reserved. C1 NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Abazajian, KN (reprint author), NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. EM aba@fnal.gov NR 97 TC 44 Z9 44 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-6505 EI 1873-2852 J9 ASTROPART PHYS JI Astropart Phys. PD MAY PY 2003 VL 19 IS 2 BP 303 EP 312 DI 10.1016/S0927-6505(02)00204-9 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 665JH UT WOS:000182116100010 ER PT J AU Lu, NY Helou, G Werner, MW Dinerstein, HL Dale, DA Silbermann, NA Malhotra, S Beichman, CA Jarrett, TH AF Lu, NY Helou, G Werner, MW Dinerstein, HL Dale, DA Silbermann, NA Malhotra, S Beichman, CA Jarrett, TH TI Infrared emission of normal galaxies from 2.5 to 12 micron: Infrared Space Observatory spectra, near-infrared continuum, and mid-infrared emission features SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; galaxies : ISM; infrared : galaxies; infrared : ISM; ISM : lines and bands ID POLYCYCLIC AROMATIC-HYDROCARBONS; COMPOSITE STELLAR-SYSTEMS; VISUAL REFLECTION NEBULAE; H-II REGIONS; INTERSTELLAR-MEDIUM; MIDINFRARED SPECTRA; UIR BANDS; MU-M; ELLIPTIC GALAXIES; JHK OBSERVATIONS AB We present ISOPHOT spectra of the regions 2.5-4.9 mum and 5.8-11.6 mum for a sample of 45 disk galaxies from the US Infrared Space Observatory Key Project on Normal Galaxies. The galaxies were selected to span the range in global properties of normal, star-forming disk galaxies in the local universe. The spectra can be decomposed into three spectral components: ( 1) continuum emission from stellar photospheres, which dominates the near-infrared (NIR; 2.5-4.9 mum) spectral region; ( 2) a weak NIR excess continuum, which has a color temperature of similar to10(3) K, carries a luminosity of a few percent of the total far-infrared (FIR) dust luminosity L-FIR and most likely arises from the interstellar medium ( ISM); and ( 3) the well-known broad emission features at 6.2, 7.7, 8.6, and 11.3 mum, which are generally attributed to aromatic carbon particles. These aromatic features in emission (AFEs) dominate the mid-infrared (MIR; 5.8-11.6 mum) part of the spectrum and resemble the so-called type A spectra observed in many nonstellar sources and the diffuse ISM in our own Galaxy. The few notable exceptions include NGC 4418, where a dust continuum replaces the AFEs in MIR, and NGC 1569, where the AFEs are weak and the strongest emission feature is [ S IV] 10.51 mum. The relative strengths of the AFEs vary by 15%-25% among the galaxies. However, little correlation is seen between these variations and either IRAS 60 mum/100 mum flux density ratio R(60/100) or the FIR/blue luminosity ratio L-FIR/L-B, two widely used indicators of the current star formation activity, suggesting that the observed variations are not a consequence of the radiation field differences among the galaxies. We demonstrate that the NIR excess continuum and AFE emission are correlated, suggesting that they are produced by similar mechanisms and similar ( or the same) material. On the other hand, as the current star formation activity increases, the overall strengths of the AFEs and the NIR excess continuum drop significantly with respect to that of the FIR emission from large dust grains. In particular, the summed luminosity of the AFEs falls from similar to0.2 L-FIR for the most "IR-quiescent'' galaxies to similar to0.1 L-FIR for the most "IR-active'' galaxies. This is likely a consequence of the preferential destruction in intense radiation fields of the small carriers responsible for the NIR/AFE emission. C1 CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP CALTECH, Ctr Infrared Proc & Anal, MS 100-22, Pasadena, CA 91125 USA. EM lu@ipac.caltech.edu; gxh@ipac.caltech.edu; mwerner@sirtfweb.jpl.nasa.gov; harriet@astro.as.utexas.edu; ddale@uwyo.edu; nancys@ipac.caltech.edu; san@tarkus.pha.jhu.edu; chas@mail1.jpl.nasa.gov; jarrett@ipac.caltech.edu NR 94 TC 131 Z9 131 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2003 VL 588 IS 1 BP 199 EP 217 DI 10.1086/374043 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 671EF UT WOS:000182451800017 ER PT J AU Kuntz, KD Snowden, SL Pence, WD Mukai, K AF Kuntz, KD Snowden, SL Pence, WD Mukai, K TI Diffuse X-ray emission from M101 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : halos; galaxies : individual (M101, NGC 5457); galaxies : ISM; X-rays : diffuse background; X-rays : galaxies; X-rays : ISM ID H-II-REGIONS; RADIO-CONTINUUM EMISSION; ON SPIRAL GALAXIES; SUPERNOVA-REMNANTS; THIN PLASMAS; MILKY-WAY; MASS; ABUNDANCE; DISK; KINEMATICS AB The total 0.45-1.0 keV luminosity of M101 is 3.2 x 10(39) ergs s(-1), of which 2.3 x 10(39) ergs s(-1) is due to diffuse emission. (Chandra observes only similar to60% of the diffuse emission observed by ROSAT because of its superior point-source detection.) Of the diffuse emission seen by Chandra, no more than 6% can be due to luminous unresolved point sources, such as X-ray binaries, and similar to10% is likely due to dwarf stars. The diffuse emission traces the spiral arms and is roughly correlated with the Halpha and far-UV emission. The radial distribution closely follows the optical profile. The bulk of the diffuse emission is characterized by a two-thermal component spectrum with kT = 0.20 and 0.75 keV, and the ratio of the emission measures of the two components is roughly constant as a function of both radius and surface brightness. The softer component has a sufficiently large covering factor that the bulk of the emission is likely extraplanar. We find no evidence of an extended axisymmetric X-ray halo, suggesting that any such halo has a strength much smaller than current predictions. C1 Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kuntz, KD (reprint author), NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. RI Snowden, Steven/D-5292-2012 NR 77 TC 28 Z9 28 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2003 VL 588 IS 1 BP 264 EP 280 DI 10.1086/373947 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 671EF UT WOS:000182451800021 ER PT J AU Hollis, JM Pedelty, JA Snyder, LE Jewell, PR Lovas, FJ Palmer, P Liu, SY AF Hollis, JM Pedelty, JA Snyder, LE Jewell, PR Lovas, FJ Palmer, P Liu, SY TI A sensitive very large array search for small-scale glycine emission toward OMC-1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : abundances; ISM : clouds; ISM : individual (OMC-1) ISM : molecules; radio lines : ISM ID INTERSTELLAR ICE ANALOGS; AMINO-ACIDS; ORION-KL; MILLIMETER-WAVE; FORMIC-ACID; ACETIC-ACID; SPECTRUM; CORES AB We have conducted a deep Q-band (lambda similar to 7 mm) search with the Very Large Array (VLA) toward OMC-1 for the lowest energy conformation ( conformer I) of glycine (NH2CH2COOH) in four rotational transitions: 6(15)-5(14), 6(24)-5(23), 7(17)-6(16), and 7(07)-6(06). Our VLA observations sample the smallest scale structures to date in the search for glycine toward OMC-1. No glycine emission features were detected. Thus, if glycine exists in OMC-1, it is below our detection limit, or it is more spatially extended than other large molecules in this source, or it is primarily in its high-energy form (conformer II). Our VLA glycine fractional abundance limits in OMC-1 are comparable to those determined from previous IRAM 30 m measurements-somewhat better or worse depending on the specific source model-and the entire similar to1' primary beam of the VLA was searched while sensitive to an areal spatial scale similar to150 times smaller than the 24" beam of the IRAM single-element telescope. In the course of this work, we detected and imaged the 4(14)-3(13) A and E transitions of methyl formate (HCOOCH3) and also the 2(02)-1(01) transition of formic acid (HCOOH). Since formic acid is a possible precursor to glycine, our glycine limits and formic acid results provide a constraint on this potential formation chemistry route for glycine in OMC-1. C1 NASA, Goddard Space Flight Ctr, Earth & Space Data Comp Div, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Natl Radio Astron Observ, Green Bank, WV 24944 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. CALTECH, Dept Astron, Pasadena, CA 91125 USA. RP Hollis, JM (reprint author), NASA, Goddard Space Flight Ctr, Earth & Space Data Comp Div, Code 930, Greenbelt, MD 20771 USA. NR 35 TC 43 Z9 43 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2003 VL 588 IS 1 BP 353 EP 359 DI 10.1086/373945 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 671EF UT WOS:000182451800029 ER PT J AU Wolf, S Padgett, DL Stapelfeldt, KR AF Wolf, S Padgett, DL Stapelfeldt, KR TI The circumstellar disk of the Butterfly star in Taurus SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; circumstellar matter; radiative transfer; scattering; stars : individual ( IRAS 04302+2247); stars : pre-main-sequence ID YOUNG STELLAR OBJECTS; SPECTRAL ENERGY-DISTRIBUTIONS; MONTE-CARLO METHOD; SIZE DISTRIBUTION; IMAGING POLARIMETRY; MOLECULAR CLOUDS; DUST PARTICLES; GRAINS; EVOLUTION; ACCRETION AB We present a model of the circumstellar environment of the so-called Butterfly star in Taurus (IRAS 04302+2247). The appearance of this young stellar object is dominated by a large circumstellar disk seen edge-on and the light-scattering lobes above the disk. Our model is based on multiwavelength continuum observations: (1) millimeter maps and (2) high-resolution near-infrared images obtained with Hubble Space Telescope/NICMOS. The advantage of the combination of both observations is that they trace (1) different regions of the system and (2) different physical processes. On the one hand, the millimeter observations are sensitive to the long-wavelength radiation being reemitted from the dust in the central parts close to the midplane of the circumstellar disk. Thus, the geometry and small-scale density distribution of the disk has been studied. Furthermore, in contrast to the pure flux measurement, the resolved 1.3 mm image allows us to discriminate between different disk models with a similar far-infrared/millimeter spectral energy distribution and therefore to disentangle the disk geometry much more precisely. On the other hand, the near-infrared observations trace the envelope structure and dust properties in the envelope and the disk surface. We find disk and envelope parameters that are comparable with those of the circumstellar environment of other young stellar objects. A main result is that the dust properties must be different in the circumstellar disk and in the envelope: while a grain size distribution with grain radii up to 100 mum is required to reproduce the millimeter observations of the disk, the envelope is dominated by smaller grains similar to those of the interstellar medium. Alternatives to this grain growth scenario in the circumstellar disk are discussed in brief as well. C1 CALTECH, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wolf, S (reprint author), CALTECH, 1200 E Calif Blvd,Mail Code 220-6, Pasadena, CA 91125 USA. RI Stapelfeldt, Karl/D-2721-2012 NR 64 TC 97 Z9 98 U1 0 U2 27 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 2003 VL 588 IS 1 BP 373 EP 386 DI 10.1086/374041 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 671EF UT WOS:000182451800031 ER PT J AU Muslimov, AG Harding, AK AF Muslimov, AG Harding, AK TI Extended acceleration in slot gaps and pulsar high-energy emission 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; RADIATION PAIR FRONTS; POLAR CAPS; ENERGETICS; CASCADES; SPECTRUM AB We revise the physics of primary electron acceleration in the "slot gap" (SG) above the pulsar polar caps (PCs), a regime originally proposed by Arons & Scharlemann in their electrodynamic model of pulsar PCs. We employ the standard definition of the SG as a pair-free space between the last open field lines and the boundary of the pair plasma column that is expected to develop above the bulk of the PC. The rationale for our revision is that the proper treatment of primary acceleration within the pulsar SGs should take into account the effect of the narrow geometry of the gap on the electrodynamics within the gap and also include the effect of inertial frame dragging on the particle acceleration. We show that the accelerating electric field within the gap, being significantly boosted by the effect of frame dragging, becomes reduced because of the gap geometry by a factor proportional to the square of the SG width. The combination of the effects of frame dragging and geometrical screening in the gap region naturally gives rise to a regime of extended acceleration, which is not limited to "favorably curved" field lines as in earlier models, and the possibility of multiple-pair production by curvature photons at very high altitudes, up to several stellar radii. We present our estimates of the characteristic SG thickness across the PC, energetics of primaries accelerated within the gap, high-energy bolometric luminosities emitted from the high altitudes in the gaps, and maximum heating luminosities produced by positrons returning from the elevated pair fronts. The estimated theoretical high-energy luminosities are in good agreement with the corresponding empirical relationships for gamma-ray pulsars. We illustrate the results of our modeling of the pair cascades and gamma-ray emission from the high altitudes in the SG for the Crab pulsar. The combination of the frame-dragging field and high-altitude SG emission enables both acceleration at the smaller inclination angles and a larger emission beam, both necessary to produce widely spaced double-peaked profiles. 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 27 TC 127 Z9 129 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 2003 VL 588 IS 1 BP 430 EP 440 DI 10.1086/368162 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 671EF UT WOS:000182451800036 ER PT J AU Brittain, SD Rettig, TW Simon, T Kulesa, C DiSanti, MA Dello Russo, N AF Brittain, SD Rettig, TW Simon, T Kulesa, C DiSanti, MA Dello Russo, N TI CO emission from disks around AB Aurigae and HD 141569: Implications for disk structure and planet formation timescales SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; ISM : molecules; planetary systems : protoplanetary disks ID HERBIG AE/BE STARS; SPECTRAL ENERGY-DISTRIBUTIONS; INTERMEDIATE-MASS STARS; MAIN-SEQUENCE STARS; PASSIVE T-TAURI; YOUNG STARS; CARBON-MONOXIDE; HIGH-RESOLUTION; CIRCUMSTELLAR DISKS; INFRARED-EMISSION AB We present a comparison of CO fundamental rovibrational lines (observed in the M band near 4.7 mum) from the inner circumstellar disks around the Herbig AeBe stars AB Aur and HD 141569. The CO spatial profiles and temperatures constrain the location of the gas for both stars to a distance of less than 50 AU. The CO emission from the disk of the similar to4 Myr star AB Aur shows at least two temperature components, the inner disk at a rotational temperature of 1540 +/- 80 K and the outer disk at 70 +/- 10 K. The hot gas is located near the hot bright inner rim of the disk and the cold gas is located in the outer disk from 8-50 AU. The relative intensities of low-J lines suggest that the cold gas is optically thick. The excitation of CO in both temperature regimes is dominated by infrared fluorescence (resonant scattering). In the more evolved disk around HD 141569, the CO is excited by UV fluorescence. The relative intensity of the CO emission lines implies a rotational temperature of 190 +/- 30 K. The resulting column density is similar to10(11) cm-2, indicating approximately 10(19) g of CO. The observed line profiles indicate that the inner disk has been cleared of CO gas by stellar radiation out to a minimum of 17 AU. The residual mass of CO suggests that the inner disk of HD 141569 is not in an active phase of planet building but it does not rule out the possibility that giant planet building has previously occurred. C1 Univ Notre Dame, Ctr Astrophys, Notre Dame, IN 46556 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. RP Brittain, SD (reprint author), Univ Notre Dame, Ctr Astrophys, Notre Dame, IN 46556 USA. RI Brittain, Sean/K-9001-2012; Dello Russo, Neil/G-2727-2015 OI Brittain, Sean/0000-0001-5638-1330; Dello Russo, Neil/0000-0002-8379-7304 NR 52 TC 88 Z9 88 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 MAY 1 PY 2003 VL 588 IS 1 BP 535 EP 544 DI 10.1086/373987 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 671EF UT WOS:000182451800044 ER PT J AU Gallagher, PT Lawrence, GR Dennis, BR AF Gallagher, PT Lawrence, GR Dennis, BR TI Rapid acceleration of a coronal mass ejection in the low corona and implications for propagation SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona; Sun : coronal mass ejections (CMEs); Sun : flares ID MAGNETIC-FLUX ROPES; SOLAR; FLARES AB A high-velocity coronal mass ejection (CME) associated with the 2002 April 21 X1.5 flare is studied using a unique set of observations from the Transition Region and Coronal Explorer ( TRACE), the Ultraviolet Coronagraph Spectrometer (UVCS), and the Large Angle and Spectroscopic Coronagraph (LASCO). The event is first observed as a rapid rise in GOES X-rays, followed by two simultaneous brightenings that appear to be connected by an ascending looplike feature. While expanding, the appearance of the feature remains remarkably constant as it passes through the TRACE 195 Angstrom passband and LASCO fields of view, allowing its height-time behavior to be accurately determined. The acceleration is consistent with an exponential rise with an e-folding time of similar to138 s and peaks at similar to1500 m s(-2) when the leading edge is at similar to1.7 R., from Sun center. The acceleration subsequently falls off with an e-folding time of over 1000 s. At distances beyond similar to3.4 R., the height-time profile is approximately linear with a constant velocity of similar to2500 km s(-1). These results are briefly discussed in light of recent kinematic models of CMEs. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Gallagher, PT (reprint author), L3 Commun EER Syst Inc, 3750 Centerview Dr, Chantilly, VA 20151 USA. RI Dennis, Brian/C-9511-2012; Gallagher, Peter/C-7717-2011 OI Gallagher, Peter/0000-0001-9745-0400 NR 19 TC 107 Z9 108 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2003 VL 588 IS 1 BP L53 EP L56 DI 10.1086/375504 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 671EG UT WOS:000182451900014 ER PT J AU Wakker, BP Savage, BD Sembach, KR Richter, P Meade, M Jenkins, EB Shull, JM Ake, TB Blair, WP Dixon, WV Friedman, SD Green, JC Green, RF Kruk, JW Moos, HW Murphy, EM Oegerle, WR Sahnow, DJ Sonneborn, G Wilkinson, E York, DG AF Wakker, BP Savage, BD Sembach, KR Richter, P Meade, M Jenkins, EB Shull, JM Ake, TB Blair, WP Dixon, WV Friedman, SD Green, JC Green, RF Kruk, JW Moos, HW Murphy, EM Oegerle, WR Sahnow, DJ Sonneborn, G Wilkinson, E York, DG TI The Far Ultraviolet Spectroscopic Explorer survey of O VI absorption in and near the Galaxy SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE Galaxy : halo; ISM : structure; ultraviolet : ISM ID HIGH-VELOCITY CLOUDS; HUBBLE-SPACE-TELESCOPE; INTERSTELLAR ABSORPTION; MOLECULAR-HYDROGEN; MAGELLANIC STREAM; FUSE OBSERVATIONS; GALACTIC HALO; BAND SYSTEM; LINES; GAS AB We present Far Ultraviolet Spectroscopic Explorer (FUSE) observations of the O vi lambdalambda1031.926, 1037.617 absorption lines associated with gas in and near the MilkyWay, as detected in the spectra of a sample of 100 extragalactic targets and two distant halo stars. We combine data from several FUSE Science Team programs with guest observer data that were public before 2002 May 1. The sight lines cover most of the sky above Galactic latitude |b| > 25degrees - at lower latitude the ultraviolet extinction is usually too large for extragalactic observations. We describe the details of the calibration, alignment in velocity, continuum fitting, and manner in which several contaminants were removed - Galactic H-2, absorption intrinsic to the background target and intergalactic Ly beta lines. This decontamination was done very carefully, and in several sight lines very subtle problems were found. We searched for O vi absorption in the velocity range -1200 to 1200 km s(-1). With a few exceptions, we only. nd O vi in the velocity range - 400 to 400 km s(-1); the exceptions may be intergalactic O vi. In this paper we analyze the O vi associated with the Milky Way ( and possibly with the Local Group). We discuss the separation of the observed O vi absorption into components associated with the MilkyWay halo and components at high velocity, which are probably located in the neighborhood of the Milky Way. We describe the measurements of equivalent width and column density, and we analyze the different contributions to the errors. We conclude that low-velocity Galactic O vi absorption occurs along all sight lines - the few nondetections only occur in noisy spectra. We further show that high-velocity O vi is very common, having equivalent width > 65 mAngstrom in 50% of the sight lines and equivalent width > 30 mAngstrom in 70% of the high-quality sight lines. The central velocities of high-velocity O vi components range from |(v)(LSR)| = 100 to 330 km s(-1); there is no correlation between velocity and absorption strength. We discuss the possibilities for studying O vi absorption associated with Local Group galaxies and conclude that O vi is probably detected in M31 and M33. We limit the extent of an O vi halo around M33 to be < 100 kpc [at a 3 σ detection limit of log N(O vi) - 14.0]. Using the measured column densities, we present 50 km s(-1) wide O vi channel maps. These show evidence for the imprint of Galactic rotation. They also highlight two known H I high-velocity clouds ( complex C and the Magellanic Stream). The channel maps further show that O vi at velocities < - 200 km s(-1) occurs along all sight lines in the region l = 20degrees-150degrees, b < - 30&DEG;, while O vi at velocities > 200 km s(-1) occurs along all sight lines in the region l = 180degrees- 300degrees, b > 20degrees. C1 Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Osserv Astrofis Arcetri, I-50125 Florence, Italy. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Comp Sci Corp, Sci Programs, Lanham, MD 20706 USA. Univ Colorado, Ctr Astrophys & Space Astron, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. RP Wakker, BP (reprint author), Univ Wisconsin, Dept Astron, 475 N Charter St, Madison, WI 53706 USA. RI Oegerle, William/C-9070-2012; Sonneborn, George/D-5255-2012; Kruk, Jeffrey/G-4047-2012; Jenkins, Edward/P-5684-2014 OI Jenkins, Edward/0000-0003-1892-4423 NR 62 TC 138 Z9 139 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 2003 VL 146 IS 1 BP 1 EP 123 DI 10.1086/346230 PG 123 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 670JR UT WOS:000182404600001 ER PT J AU Savage, BD Sembach, KR Wakker, BP Richter, P Meade, M Jenkins, EB Shull, JM Moos, HW Sonneborn, G AF Savage, BD Sembach, KR Wakker, BP Richter, P Meade, M Jenkins, EB Shull, JM Moos, HW Sonneborn, G TI Distribution and kinematics of O VI in the Galactic halo SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE Galaxy : halo; ISM : abundances; ISM : clouds; ultraviolet : ISM ID SPECTROSCOPIC-EXPLORER OBSERVATIONS; FAR-ULTRAVIOLET SPECTROSCOPY; IONIZED INTERSTELLAR GAS; INTERMEDIATE-VELOCITY GAS; SMALL-MAGELLANIC-CLOUD; PG 1159 STARS; ABSORPTION-LINES; CORONAL GAS; H-I; SUPERNOVA-REMNANTS AB Far-Ultraviolet Spectroscopic Explorer ( FUSE) spectra of 100 extragalactic objects and two distant halo stars are analyzed to obtain measures of O VI lambdalambda1031.93, 1037.62 absorption along paths through the Milky Way thick disk/halo. Strong O VI absorption over the velocity range from -100 to 100 km s(-1) reveals a wide-spread but highly irregular distribution of O VI, implying the existence of substantial amounts of hot gas with T similar to 3 x 10(5) K in the Milky Way thick disk/halo. The integrated column density, log [N(O VI) cm(-2)], ranges from 13.85 to 14.78 with an average value of 14.38 and a standard deviation of 0.18. Large irregularities in the gas distribution are found to be similar over angular scales extending from <1 degrees to 180 degrees, implying a considerable amount of small- and large-scale structure in the absorbing gas. The overall distribution of O vi is not well described by a symmetrical plane-parallel layer of patchy O VI absorption. The simplest departure from such a model that provides a reasonable fit to the observations is a plane-parallel patchy absorbing layer with an average O VI midplane density of n(0)(O VI) = 1.7 x 10(-8) cm(-3), a scale height of similar to 2.3 kpc, and a similar to 0.25 dex excess of O VI in the northern Galactic polar region. The distribution of O VI over the sky is poorly correlated with other tracers of gas in the halo, including low- and intermediate-velocity H I, H alpha emission from the warm ionized gas at similar to 10(4) K, and hot X-ray-emitting gas at similar to 10(6) K. The O vi has an average velocity dispersion, b approximate to 60 km s(-1), and standard deviation of 15 km s(-1). Thermal broadening alone cannot explain the large observed pro. le widths. The average O VI absorption velocities toward high-latitude objects (\b\ > 45degrees) range from -46 to 82 km s(-1), with a high-latitude sample average of 0 km s(-1) and a standard deviation of 21 km s(-1). High positive velocity O VI absorbing wings extending from similar to100 to similar to250 km s(-1) observed along 21 lines of sight may be tracing the flow of O VI into the halo. A combination of models involving the radiative cooling of hot fountain gas, the cooling of supernova bubbles in the halo, and the turbulent mixing of warm and hot halo gases is required to explain the presence of O VI and other highly ionized atoms found in the halo. The preferential venting of hot gas from local bubbles and superbubbles into the northern Galactic polar region may explain the enhancement of O VI in the north. If a fountain flow dominates, a mass flow rate of approximately 1.4 M. yr(-1) of cooling hot gas to each side of the Galactic plane with an average density of 10(-3) cm(-3) is required to explain the average value of log [N(O VI) sin \b\] observed in the southern Galactic hemisphere. Such a flow rate is comparable to that estimated for the Galactic intermediate-velocity clouds. C1 Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. Univ Colorado, Ctr Astrophys & Space Astron, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Savage, BD (reprint author), Univ Wisconsin, Dept Astron, 475 N Charter St, Madison, WI 53706 USA. RI Sonneborn, George/D-5255-2012; Jenkins, Edward/P-5684-2014 OI Jenkins, Edward/0000-0003-1892-4423 NR 99 TC 160 Z9 161 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 2003 VL 146 IS 1 BP 125 EP 164 DI 10.1086/346229 PG 40 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 670JR UT WOS:000182404600002 ER PT J AU Sembach, KR Wakker, BP Savage, BD Richter, P Meade, M Shull, JM Jenkins, EB Sonneborn, G Moos, HW AF Sembach, KR Wakker, BP Savage, BD Richter, P Meade, M Shull, JM Jenkins, EB Sonneborn, G Moos, HW TI Highly ionized high-velocity gas in the vicinity of the Galaxy SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Review DE Galaxy : halo; intergalactic medium; ISM : clouds; ISM : evolution; ISM : kinematics and dynamics; ultraviolet : ISM ID ULTRAVIOLET-SPECTROSCOPIC-EXPLORER; SMALL-MAGELLANIC-CLOUD; H-ALPHA-EMISSION; ABSORPTION-LINE SYSTEMS; ON-ORBIT PERFORMANCE; N-BODY SIMULATIONS; GALACTIC HALO; INTERSTELLAR-MEDIUM; LOCAL GROUP; INTERGALACTIC MEDIUM AB We report the results of a FUSE study of high-velocity O VI absorption along complete sight lines through the Galactic halo in directions toward 100 extragalactic objects and two halo stars. The high-velocity O VI traces a variety of phenomena, including tidal interactions with the Magellanic Clouds, accretion of gas, out. owing material from the Galactic disk, warm/hot gas interactions in a highly extended Galactic corona, and intergalactic gas in the Local Group. We identify 84 high-velocity O VI features at greater than or equal to3 sigma confidence at velocities of -500 < v(LSR) < +500 km s(-1). The 84 O VI features have velocity centroids ranging from -372 less than or similar to (v) over bar (LSR) less than or similar to -90 km s(-1) to +93 less than or similar to (v) over bar (LSR) less than or similar to 385 km s(-1), line widths b similar to 16-72 km s(-1) with an average of [b] = 40 +/- 13 km s(-1), and an average O VI column density [log N] = 13.95 +/- 0.34 with a median value of 13.97. Values of b greater than the 17.6 km s(-1) thermal width expected for O VI at T similar to 3 x 10(5) K indicate that additional nonthermal broadening mechanisms are common. The O VI lambda1031.926 absorption is detected at greater than or equal to3 sigma confidence along 59 of the 102 sight lines surveyed. The high-velocity O VI detections indicate that similar to60% of the sky (and perhaps as much as similar to85%, depending on data quality considerations) is covered by high-velocity H(+) associated with the O VI. We find that N(H(+)) greater than or similar to 10(18) cm(-2) if the high-velocity hot gas has a metallicity similar to that of the Magellanic Stream; this detection rate is considerably higher than that of high-velocity warm H I traced through its 21 cm emission at a comparable column density level. Some of the high-velocity O VI is associated with known H I structures (the Magellanic Stream, Complex A, Complex C, the Outer Spiral Arm, and several discrete H I HVCs). Some of the high-velocity O VI features have no counterpart in H I 21 cm emission, including discrete absorption features and positive velocity absorption wings extending from similar to100 to similar to300 km s(-1) that blend with lower velocity absorption produced by the Galactic thick disk/halo. The discrete features may typify clouds located in the Local Group, while the O VI absorption wings may be tidal debris or material expelled from the Galactic disk. Most of the O VI features have velocities incompatible with those of the Galactic halo, even if the halo has decoupled from the underlying Galactic disk. The reduction in the dispersion about the mean of the high-velocity O VI centroids when the velocities are converted from the LSR to the GSR and LGSR reference frames is necessary (but not conclusive) evidence that some of the clouds are located outside the Galaxy. Most of the O VI cannot be produced by photoionization, even if the gas is irradiated by extragalactic ultraviolet background radiation. Several observational quantities indicate that collisions in hot gas are the primary ionization mechanism responsible for the production of the O VI. These include the ratios of O VI column densities to those of other highly ionized species (C IV, N V) and the strong correlation between N(O VI) and O VI line width. Consideration of the possible sources of collisional ionization favors production of some of the O VI at the boundaries between cool/warm clouds of gas and a highly extended (R greater than or similar to 70 kpc), hot (T > 10(6) K), low-density (n less than or similar to 10(-4) -10(-5) cm(-3)) Galactic corona or Local Group medium. The existence of a hot, highly extended Galactic corona or Local Group medium and the prevalence of high-velocity O VI are consistent with predictions of current galaxy formation scenarios. Distinguishing between the various phenomena producing high-velocity O VI in and near the Galaxy will require continuing studies of the distances, kinematics, elemental abundances, and physical states of the different types of high-velocity O VI found in this study. Descriptions of galaxy evolution will need to account for the highly ionized gas, and future X-ray studies of hot gas in the Local Group will need to consider carefully the relationship of the X-ray absorption/emission to the complex high-velocity absorption observed in O VI. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Univ Colorado, Ctr Astrophys & Space Astron, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Sembach, KR (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. EM sembach@stsci.edu RI Sonneborn, George/D-5255-2012; Jenkins, Edward/P-5684-2014 OI Jenkins, Edward/0000-0003-1892-4423 NR 151 TC 339 Z9 341 U1 0 U2 1 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 MAY PY 2003 VL 146 IS 1 BP 165 EP 208 DI 10.1086/346231 PG 44 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 670JR UT WOS:000182404600003 ER PT J AU Bell, N Heard, DE Pilling, MJ Tomlin, AS AF Bell, N Heard, DE Pilling, MJ Tomlin, AS TI Atmospheric lifetime as a probe of radical chemistry in the boundary layer SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE photochemistry; hydrogen oxides; chemical lifetimes; perturbation analysis; eigenmodes ID OH PHOTOCHEMISTRY EXPERIMENT; TROPOSPHERIC OH; TIME SCALES; HO2; COLORADO AB Determination of the atmospheric lifetime of radical species provides a potentially powerful method to resolve discrepancies between their modelled and measured concentrations. Theoretical perturbation analysis is employed to investigate the relationship between atmospheric lifetime (tau) and decay time (lambda(-1)) following concentration perturbation for OH and HO2 using a model system with constrained NOx. It is shown that feedback from HO2 to OH can lead to a non-equivalence of (tau) and (lambda(-1)), depending on the size of the feedback term and the difference in the atmospheric lifetimes of the coupled species. The ideas are applied and extended in a discussion of atmospheric field data from the EASE96 campaign at a remote coastal site. Dynamic information about the relaxation modes and species couplings, available from the eigenvector elements, is investigated for the systems studied. In general, the results suggest that the assignment of a specific decay time to OH is feasible for background boundary layer tropospheric conditions. However, complex couplings between peroxy species lead to non-separable time scales for these species. The relevance of results for the development of a field instrument to measure OH lifetime is discussed. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Univ Leeds, Sch Med, Leeds LS2 9JT, W Yorkshire, England. Univ Leeds, Dept Fuel & Energy, Leeds LS2 9JT, W Yorkshire, England. RP Bell, N (reprint author), Columbia Univ, NASA, Goddard Inst Space Studies, New York, NY 10027 USA. RI Unger, Nadine/M-9360-2015; OI Heard, Dwayne/0000-0002-0357-6238 NR 34 TC 6 Z9 6 U1 0 U2 9 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 MAY PY 2003 VL 37 IS 16 BP 2193 EP 2205 DI 10.1016/S1352-2310(03)00157-2 PG 13 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 676XY UT WOS:000182778900003 ER PT J AU Kraft, NO Lyons, TJ Binder, H AF Kraft, NO Lyons, TJ Binder, H TI Intercultural crew issues in long-duration spaceflight SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Editorial Material DE long-duration spaceflight; missions; mission control; culture ID SPACE MISSIONS AB Before long-duration flights with international crews can be safely undertaken, potential interpersonal difficulties will need to be addressed. Crew performance breakdown has been recognized by the American Institute of Medicine, in scientific literature, and in popular culture. However, few studies of human interaction and performance in confined, isolated environments exist, and the data pertaining to those studies are mostly anecdotal. Many incidents involving crew interpersonal dynamics, those among flight crews, as well as between flight crews and ground controllers, are reported only in non-peer reviewed books and newspapers. Consequently, due to this lack of concrete knowledge, the selection of astronauts and cosmonauts has focused on individual rather than group selection. Additional selection criteria such as interpersonal and communication competence, along with intercultural training, will have a decisive impact on future mission success. Furthermore, industrial psychological research has demonstrated the ability to select a group based on compatibility. With all this in mind, it is essential to conduct further research on heterogeneous, multi-national crews including selection and training for long-duration space missions. C1 NASA, Ames Res Ctr, Human Factors Res & Technol Div, Moffett Field, CA 94035 USA. Asian Off Aerosp Res & Dev, Tokyo, Japan. RP Kraft, NO (reprint author), NASA, Ames Res Ctr, Human Factors Res & Technol Div, Mail Stop 262-4, Moffett Field, CA 94035 USA. NR 24 TC 9 Z9 9 U1 0 U2 2 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 2003 VL 74 IS 5 BP 575 EP 578 PG 4 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 673YH UT WOS:000182608300014 PM 12751589 ER PT J AU Mogul, R Bol'shakov, AA Chan, SL Stevens, RM Khare, BN Meyyappan, M Trent, JD AF Mogul, R Bol'shakov, AA Chan, SL Stevens, RM Khare, BN Meyyappan, M Trent, JD TI Impact of low-temperature plasmas on Deinococcus radiodurans and biomolecules SO BIOTECHNOLOGY PROGRESS LA English DT Article ID GLOW-DISCHARGE PLASMA; THERMAL STERILIZATION; RADIATION-RESISTANCE; GAMMA-IRRADIATION; MEDICAL DEVICES; DNA; INACTIVATION; DISINFECTION; DEGRADATION; SENSITIVITY AB The effects of cold plasma on Deinococcus radiodurans, plasmid DNA, and model proteins were assessed using microbiological, spectrometric, and biochemical techniques. In low power O-2 plasma (similar to25 W, similar to45 mTorr, 90 min), D. radiodurans, a radiation-resistant bacterium, showed a 99.999% reduction in bioburden. In higher power O-2 plasma (100 W and 500 mTorr), the reduction rate increased about 10-fold and observation by atomic force microscopy showed significant damage to the cell. Damage to cellular lipids, proteins, and chromosome was indicated by losses of infrared spectroscopic peaks at 2930, 1651, 1538, and 1245 cm(-1), respectively. In vitro experiments show that O-2 plasmas induce DNA strand scissions and cross-linking as well as reduction of enzyme activity. The observed degradation and removal of biomolecules was power-dependent. Exposures to 200 W at 500 mTorr removed biomolecules to below detection limits in 60 s. Emission spectroscopy indicated that D. radiodurans cells were volatilized into CO2, CO, N-2, and H2O, confirming that these plasmas were removing complex biological matter from surfaces. A CO2 plasma was not as effective as the O-2 plasma, indicating the importance of plasma composition and the dominant role of chemical degradation. Together, these findings have implications for NASA planetary protection schemes and for the contamination of Mars. C1 NASA, Ames Res Ctr, Plasma Res Grp, Astrobiol Technol Branch, Moffett Field, CA 94035 USA. Eloret Corp, Sunnyvale, CA 94087 USA. SETI Inst, Mountain View, CA 94043 USA. RP Trent, JD (reprint author), NASA, Ames Res Ctr, Plasma Res Grp, Astrobiol Technol Branch, Moffett Field, CA 94035 USA. RI Bol'shakov, Alexander/A-9258-2015 OI Bol'shakov, Alexander/0000-0002-6034-7079 NR 39 TC 50 Z9 51 U1 2 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 8756-7938 J9 BIOTECHNOL PROGR JI Biotechnol. Prog. PD MAY-JUN PY 2003 VL 19 IS 3 BP 776 EP 783 DI 10.1021/bp025665e PG 8 WC Biotechnology & Applied Microbiology; Food Science & Technology SC Biotechnology & Applied Microbiology; Food Science & Technology GA 740QN UT WOS:000186413200013 PM 12790638 ER PT J AU Gutsev, GL Andrews, L Bauschlicher, CW AF Gutsev, GL Andrews, L Bauschlicher, CW TI 3d-metal monocarbonyls MCO, MCO+, and MCO- (M = Sc to Cu): comparative bond strengths and catalytic ability to produce CO2 in reactions with CO SO CHEMICAL PHYSICS LA English DT Article ID WALLED CARBON NANOTUBES; DENSITY-FUNCTIONAL CALCULATIONS; COLLISION-INDUCED DISSOCIATION; TRANSITION-METAL ATOMS; COUPLED-CLUSTER THEORY; GAUSSIAN-BASIS SETS; MATRIX INFRARED-SPECTRA; ABLATED IRON ATOMS; WAVE-FUNCTIONS; SOLID ARGON AB The electronic and geometrical structures of 3d-metal monocarbonyls MCO (M = Sc to Cu), the MCO- anions and MCOdivided by cations are computed using the density functional theory with generalized gradient approximation for the exchange-correlation potential. Our calculated adiabatic electron affinities and ionization potentials are in good agreement with experiment. Using the results of our previous computations on the MC, MC-, and MC+ series, we estimated the energies required for the Boudouard disproportionation reactions MCO0,-,+ + CO --> MC0,-,+ + CO2. Among the neutrals, this reaction is endothermic by 1.30 eV for Mn, while Fe is found to be the second best atom, with the reaction being endothermic by 1.59 eV. These are substantially reduced with respect to the gas phase Boudouard reaction CO + CO --> C + CO2, which is endothermic by 5.65 eV. Several of the anions have disproportionation energies similar to the neutrals, while cations are found to be less favorable than the neutrals. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, ELORET Corp, Moffett Field, CA 94035 USA. Univ Virginia, Dept Chem, Charlottesville, VA 22901 USA. NASA, Ames Res Ctr, Space Technol Div, Moffett Field, CA 94035 USA. RP Gutsev, GL (reprint author), NASA, Ames Res Ctr, ELORET Corp, Mail Stop 230-3, Moffett Field, CA 94035 USA. EM ggutsev@mail.arc.nasa.gov NR 96 TC 23 Z9 23 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD MAY 1 PY 2003 VL 290 IS 1 BP 47 EP 58 DI 10.1016/S0301-0104(03)00097-1 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 674LB UT WOS:000182637300005 ER PT J AU Armstrong, JW Estabrook, FB Tinto, M AF Armstrong, JW Estabrook, FB Tinto, M TI Time delay interferometry SO CLASSICAL AND QUANTUM GRAVITY LA English DT Article; Proceedings Paper CT 4th International LISA Symposium CY JUL 19-24, 2002 CL PENN STATE UNIV, UNIVERSITY PK, PENNSYLVANIA HO PENN STATE UNIV ID SENSITIVITY; LISA AB Time delay interferometry (TDI) is a method for cancelling the dominant LISA instrumental noise-laser phase fluctuations-by appropriately time-shifting and adding frequency or phase data taken on optical links connecting pairs of optical benches. Here we review the principles of TDI and discuss some applications for LISA, including realistic simulations of system noise. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Armstrong, JW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 7 Z9 7 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0264-9381 J9 CLASSICAL QUANT GRAV JI Class. Quantum Gravity PD MAY PY 2003 VL 20 IS 10 BP S283 EP S289 AR PII S0264-9381(03)55733-1 DI 10.1088/0264-9381/20/10/331 PG 7 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 693HE UT WOS:000183710500032 ER PT J AU Baker, J AF Baker, J TI Modelling binary black-hole coalescence SO CLASSICAL AND QUANTUM GRAVITY LA English DT Article; Proceedings Paper CT 4th International LISA Symposium CY JUL 19-24, 2002 CL PENN STATE UNIV, UNIVERSITY PK, PENNSYLVANIA HO PENN STATE UNIV ID MERGER HISTORY; INITIAL DATA AB The final burst of radiation from the coalescence of two supermassive black holes produces extraordinary gravitational wave luminosity making these events visible to LISA even out to large redshift. Interpreting such observations will require detailed theoretical models, based on general relativity. The effort to construct these models is just beginning to produce results. I describe the Lazarus approach to modelling these radiation bursts, and present recent results which indicate that the system loses, in the last few wave cycles, about 3% of its mass-energy as strongly polarized gravitational radiation. C1 NASA, Goddard Space Flight Ctr, Lab High Energy Astrophys, Greenbelt, MD 20771 USA. RP Baker, J (reprint author), NASA, Goddard Space Flight Ctr, Lab High Energy Astrophys, Greenbelt, MD 20771 USA. NR 18 TC 0 Z9 0 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0264-9381 J9 CLASSICAL QUANT GRAV JI Class. Quantum Gravity PD MAY PY 2003 VL 20 IS 10 BP S201 EP S208 AR PII S0264-9381(03)57404-4 DI 10.1088/0264-9381/20/10/323 PG 8 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 693HE UT WOS:000183710500024 ER PT J AU Maghami, PG Hyde, TT AF Maghami, PG Hyde, TT TI Laser interferometer space antenna dynamics and controls model SO CLASSICAL AND QUANTUM GRAVITY LA English DT Article; Proceedings Paper CT 4th International LISA Symposium CY JUL 19-24, 2002 CL PENN STATE UNIV, UNIVERSITY PK, PENNSYLVANIA HO PENN STATE UNIV AB A 19 degree-of-freedom (DOF) dynamics and controls model of a laser interferometer space antenna (LISA) spacecraft has been developed. This model is used to evaluate the feasibility of the dynamic pointing and positioning requirements of a typical LISA spacecraft. These requirements must be met for LISA to be able to successfully detect gravitational waves in the frequency band of interest (0.1-100 mHz). The 19-DOF model includes all rigid-body degrees of freedom. A number of disturbance sources, both internal and external, are included. Preliminary designs for the four control systems that comprise the LISA disturbance reduction system (DRS) have been completed and are included in the model. Simulation studies are performed to demonstrate that the LISA pointing and positioning requirements are feasible and can be met. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Maghami, PG (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 5 TC 8 Z9 8 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0264-9381 J9 CLASSICAL QUANT GRAV JI Class. Quantum Gravity PD MAY PY 2003 VL 20 IS 10 BP S273 EP S282 AR PII S0264-9381(03)55725-2 DI 10.1088/0264-9381/20/10/330 PG 10 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 693HE UT WOS:000183710500031 ER PT J AU Merkowitz, SM AF Merkowitz, SM TI The LISA integrated model SO CLASSICAL AND QUANTUM GRAVITY LA English DT Article; Proceedings Paper CT 4th International LISA Symposium CY JUL 19-24, 2002 CL PENN STATE UNIV, UNIVERSITY PK, PA HO PENN STATE UNIV AB LISA has unique needs that argue for an aggressive modelling effort. These models ultimately need to forecast and interrelate the behaviour of the science input, structure, optics, control systems and many other factors that affect the performance of the flight hardware. In addition, many components of these integrated models will also be used separately for the evaluation and investigation of design choices, technology development, and integration and test. This paper presents an overview of the LISA integrated modelling effort. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Merkowitz, SM (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Merkowitz, Stephen/D-6680-2012 OI Merkowitz, Stephen/0000-0002-0412-4209 NR 5 TC 7 Z9 7 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0264-9381 EI 1361-6382 J9 CLASSICAL QUANT GRAV JI Class. Quantum Gravity PD MAY PY 2003 VL 20 IS 10 BP S255 EP S260 AR PII S0264-9381(03)55506-X DI 10.1088/0264-9381/20/10/328 PG 6 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 693HE UT WOS:000183710500029 ER PT J AU Pollack, SE Jennrich, O Stebbins, RT Bender, P AF Pollack, SE Jennrich, O Stebbins, RT Bender, P TI Status of LISA phase measurement work in the US SO CLASSICAL AND QUANTUM GRAVITY LA English DT Article; Proceedings Paper CT 4th International LISA Symposium CY JUL 19-24, 2002 CL PENN STATE UNIV, UNIVERSITY PK, PENNSYLVANIA HO PENN STATE UNIV AB Currently there are two implementations for LISA phase measurement being investigated in the United States. In this paper, we present the current status of one of these implementations, the so-called zero-crossing approach or stopwatch method. This method uses a technique of counting and timing to make phase measurements. Herein we present a description of the status of an experiment which produces an optical LISA-like fringe which we use to test our phase meter. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. ESTEC, Noordwijk, Netherlands. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pollack, SE (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Stebbins, Robin/G-5009-2013 NR 4 TC 5 Z9 5 U1 1 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0264-9381 J9 CLASSICAL QUANT GRAV JI Class. Quantum Gravity PD MAY PY 2003 VL 20 IS 10 BP S193 EP S199 AR PII S0264-9381(03)55680-5 DI 10.1088/0264-9381/20/10/322 PG 7 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 693HE UT WOS:000183710500023 ER PT J AU Schumaker, BL AF Schumaker, BL TI Disturbance reduction requirements for LISA SO CLASSICAL AND QUANTUM GRAVITY LA English DT Article; Proceedings Paper CT 4th International LISA Symposium CY JUL 19-24, 2002 CL PENN STATE UNIV, UNIVERSITY PK, PA HO PENN STATE UNIV ID MISSION; SENSOR AB An overview is given of the sources and magnitudes of acceleration disturbances to the LISA proof masses (PMs). They are classified according to their sources as environmental noise, PM position sensor back-action, control-loop noise and PM-spacecraft (SC) stiffness. A general control model is used to establish relations among the noise sources, sensor errors and control-loop elements. Quantitative estimates are derived for the noise sources, and minimum requirements are inferred for sensor resolution and SC drag-free control-loop gain that are consistent both with the baseline in-band LISA budget for total acceleration noise and a possible extension to lower frequencies. For brevity, explicit expressions for each noise source are provided in tables, together with quantitative estimates for indicated parameter values. Additional tables list assumed parameter definitions and values; acceleration-noise goals and estimated totals; and minimum requirements for sensor resolution and SC control-loop gain, for frequencies ranging from 3 mHz down to 5 x 10(-6) Hz. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Schumaker, BL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Bonny.L.Schumaker@jpl.nasa.gov NR 29 TC 43 Z9 48 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0264-9381 J9 CLASSICAL QUANT GRAV JI Class. Quantum Gravity PD MAY PY 2003 VL 20 IS 10 BP S239 EP S253 AR PII S0264-9381(03)57312-9 DI 10.1088/0264-9381/20/10/327 PG 15 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 693HE UT WOS:000183710500028 ER PT J AU Waluschka, E AF Waluschka, E TI LISA optics model SO CLASSICAL AND QUANTUM GRAVITY LA English DT Article; Proceedings Paper CT 4th International LISA Symposium CY JUL 19-24, 2002 CL PENN STATE UNIV, UNIVERSITY PK, PENNSYLVANIA HO PENN STATE UNIV AB The LISA experiment has six telescopes, in three spacecrafts, in separate orbits about the sun. There is a continuous laser link between all the spacecrafts. The use of standard optical design and analysis of computer codes is not possible because of the large, 5 million km, distances between the spacecrafts, the fact that the spacecrafts are in separate orbits and the need for subpicometre accuracies. A description of the approach used to model the optics in the spacecraft in orbit is presented and use of this model in acquisition and control strategies is briefly discussed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Waluschka, E (reprint author), NASA, Goddard Space Flight Ctr, Code 551, Greenbelt, MD 20771 USA. NR 9 TC 0 Z9 0 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0264-9381 J9 CLASSICAL QUANT GRAV JI Class. Quantum Gravity PD MAY PY 2003 VL 20 IS 10 BP S171 EP S179 AR PII S0264-9381(03)55296-0 DI 10.1088/0264-9381/20/10/320 PG 9 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 693HE UT WOS:000183710500021 ER PT J AU Williams, R Berriman, B Deelman, E Good, J Jacob, J Kesselman, C Lonsdale, C Oliver, S Prince, TA AF Williams, R Berriman, B Deelman, E Good, J Jacob, J Kesselman, C Lonsdale, C Oliver, S Prince, TA TI Multi-wavelength image space: another grid-enabled science SO CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE LA English DT Article DE astronomy; mosaicking; computational grid; montage AB We describe how the Grid enables new research possibilities in astronomy through multi-wavelength images. To see sky images in the same pixel space, they must be projected to that space, a computer-intensive process. There is thus a virtual data space induced that is defined by an image and the applied projection. This virtual data can be created and replicated with Planners and Replica catalog technology developed under the GriPhyN project. We plan to deploy our system (MONTAGE) on the U.S. Teragrid. Grid computing is also needed for ingesting data-computing background correction on each image-which forms a separate virtual data space. Multi-wavelength images can be used for pushing source detection and statistics by an order of magnitude from current techniques; for optimization of multi-wavelength image registration for detection and characterization of extended sources; and for detection of new classes of essentially multi-wavelength astronomical phenomena. The paper discusses both the Grid architecture and the scientific goals. Copyright (C) 2003 John Wiley Sons, Ltd. C1 CALTECH, Ctr Adv Comp Res, Pasadena, CA 91125 USA. CALTECH, Infrared Proc & Anal Ctr, Pasadena, CA 91125 USA. Univ So Calif, Inst Informat Sci, Marina Del Rey, CA 90292 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Sussex, Ctr Astron, Brighton BN1 9R, E Sussex, England. RP Williams, R (reprint author), CALTECH, Ctr Adv Comp Res, 158-79, Pasadena, CA 91125 USA. OI Kesselman, Carl/0000-0003-0917-1562 NR 14 TC 1 Z9 1 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1532-0626 J9 CONCURR COMP-PRACT E JI Concurr. Comput.-Pract. Exp. PD MAY PY 2003 VL 15 IS 6 BP 539 EP 549 DI 10.1002/cpe.715 PG 11 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 673UX UT WOS:000182599600001 ER PT J AU Timofeeva, TV Kuhn, GH Nesterov, VV Nesterov, VN Frazier, DO Penn, BG Antipin, MY AF Timofeeva, TV Kuhn, GH Nesterov, VV Nesterov, VN Frazier, DO Penn, BG Antipin, MY TI Cocrystal of 1,1-dicyano-2-(4-hydroxyphenyl)-ethene with L-proline and induced conformational polymorphism of 1,1-dicyano-2-(4-hydroxy-3-methoxyphenyl)-ethene SO CRYSTAL GROWTH & DESIGN LA English DT Article ID MOLECULAR MECHANICS CALCULATIONS; NONLINEAR-OPTICAL PROPERTIES; PERFECT POLAR ALIGNMENT; CRYSTAL-STRUCTURES; DICYANOVINYLBENZENE; DERIVATIVES; CHROMOPHORES; MONOHYDRATE AB Crystallization of 1,1-dicyano-2-(4-hydroxyphenyl)-ethene (I) and 1,1-dicyano-2-(4-hydroxy-3-methoxyphenyl)-ethene (II) with L-proline (III) and L-tartaric acid (IV) was carried out. Compound I formed cocrystals with L-proline I.III. However, cocrystallization of II was unsuccessful; instead in the presence of III or IV formation of two conformational polymorphs IIa and IIb was observed. In cocrystals I.III, hydrogen bonded chains of proline molecules with molecules of I attached to them were found. Similar synthons were found in the literature in other proline-containing crystals, and we believe that it is possible to use these acentric supramolecular associates in crystal engineering of nonlinear optical materials. Possible reasons for the formation of two conformational polymorphs of compound II are discussed based on the results of X-ray analysis, molecular and crystal structure energy calculations, and thermal behavior of compound II. C1 New Mexico Highlands Univ, Dept Chem, Las Vegas, NM 87701 USA. Russian Acad Sci, Inst Organoelement Cpds, Moscow, Russia. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Timofeeva, TV (reprint author), New Mexico Highlands Univ, Dept Chem, Las Vegas, NM 87701 USA. NR 24 TC 31 Z9 31 U1 4 U2 14 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 2003 VL 3 IS 3 BP 383 EP 391 DI 10.1021/cg0200513 PG 9 WC Chemistry, Multidisciplinary; Crystallography; Materials Science, Multidisciplinary SC Chemistry; Crystallography; Materials Science GA 680NP UT WOS:000182984500014 ER PT J AU Hshieh, FY Hirsch, DB Beeson, HD AF Hshieh, FY Hirsch, DB Beeson, HD TI Ignition and combustion of low-density polyimide foam SO FIRE AND MATERIALS LA English DT Article DE polyimide foam; smoldering combustion; cone calorimeter AB The ignition, flaming and smoldering combustion of low-density polyimide foam have been studied using a cone calorimeter. Low-density polyimide foam exhibits a high ignition resistance. The minimum heat flux for the ignition of flaming combustion ranges from 48 to 54 kW/m(2). This minimum heat flux also indicates the heat flux for transition from smoldering to flaming combustion. The flaming combustion results show that the heat release rate of low-density polyimide foam is very low even at a high incident heat flux of 75 kW/m(2). The smoldering combustion results show that the smoldering of low-density polyimide foam becomes significant when the incident heat flux is greater than 30 kW/m(2). The smoldering combustion of low-density polyimide foam cannot be self-sustaining when the external heat source is removed. Copyright (C) 2003 John Wiley Sons, Ltd. C1 Honeywell Technol Solut Inc, Las Cruces, NM 88004 USA. NASA, Lyndon B Johnson Space Ctr, Honeywell Technol Solut Inc, White Sands Test Facil, Houston, TX 77058 USA. RP Hshieh, FY (reprint author), Honeywell Technol Solut Inc, POB 20, Las Cruces, NM 88004 USA. NR 11 TC 14 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 0308-0501 J9 FIRE MATER JI Fire Mater. PD MAY-JUN PY 2003 VL 27 IS 3 BP 119 EP 130 DI 10.1002/fam.820 PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA 706GE UT WOS:000184444900002 ER PT J AU Mittlefehldt, DW Lindstrom, MM AF Mittlefehldt, DW Lindstrom, MM TI Geochemistry of eucrites: Genesis of basaltic eucrites, and Hf and Ta as petrogenetic indicators for altered antarctic eucrites SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID DIOGENITE PARENT BODY; ORTHO-PYROXENE; CORE FORMATION; ELEMENT CHEMISTRY; ACHONDRITES; METEORITES; VESTA; CRYSTALLIZATION; METAMORPHISM; PETROLOGY AB We performed instrumental neutron activation analysis on a large suite of antarctic and nonantarctic eucrites, including unbrecciated, brecciated, and polymict eucrites and cumulate and noncumulate eucrites. We evaluate the use of Hf and Ta, two highly incompatible elements, as sensitive indicators of partial melting or fractional crystallization processes. Comparison with rare earth element (REE) data from nonantarctic and antarctic eucrites shows that Hf and Ta are unaffected by the terrestrial alteration that has modified the REE contents and patterns of some antarctic eucrites. The major host phases for Hf and Ta-zircon, baddeleyite, ilmenite, and titanite-are much less susceptible to terrestrial alteration than the phosphate hosts of REEs. The host phases for Hf and Ta are minor or trace phases, so sample heterogeneity is a serious concern for obtaining representative compositions. The trace lithophile and siderophile element contents of noncumulate eucrites do not allow for a single, simple model for the petrogenesis of the howardite-eucrite-diogenite suite. Fractional crystallization models cannot reproduce the compositional relationship between eucrites of the main group-Nuevo Laredo trend and those of the Stannern trend. Equilibrium crystallization models cannot explain the trace element diversity observed among diogenites. Partial melting models cannot explain the W variations among eucrites, unless source regions had different metal contents. We suggest that slight variations in oxygen fugacity of eucrite source regions during partial melting can explain the W variations without requiring different metal contents. This hypothesis may fail to account for eucrite Co contents, however. Copyright (C) 2003 Elsevier Science Ltd. C1 NASA, Lyndon B Johnson Space Ctr, SR, Houston, TX 77058 USA. RP Mittlefehldt, DW (reprint author), NASA, Lyndon B Johnson Space Ctr, SR, Houston, TX 77058 USA. NR 91 TC 50 Z9 50 U1 4 U2 19 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2003 VL 67 IS 10 BP 1911 EP 1934 DI 10.1016/S0016-7037(02)01411-4 PG 24 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 678TC UT WOS:000182881700011 ER PT J AU Golombek, MP Grant, JA Parker, TJ Crisp, JA Squyres, SW AF Golombek, MP Grant, JA Parker, TJ Crisp, JA Squyres, SW TI Landing the Mars Exploration Rovers SO GEOTIMES LA English DT Article C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Natl Air Space Museum Washington, Ctr Earth & Planetary Studies, Smithsonian Inst, Washington, DC USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. RP Golombek, MP (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RI Crisp, Joy/H-8287-2016 OI Crisp, Joy/0000-0002-3202-4416 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER GEOLOGICAL INST PI ALEXANDRIA PA 4220 KING ST, ALEXANDRIA, VA 22302-1507 USA SN 0016-8556 J9 GEOTIMES JI Geotimes PD MAY PY 2003 VL 48 IS 5 BP 18 EP 23 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 779WY UT WOS:000189326000015 ER PT J AU Baliunas, S Donahue, R Rampino, MR Gaffey, MJ Shelton, JC Mohanty, S AF Baliunas, S Donahue, R Rampino, MR Gaffey, MJ Shelton, JC Mohanty, S TI Multispectral analysis of Asteroid 3 Juno taken with the 100-inch telescope at Mount Wilson Observatory SO ICARUS LA English DT Article AB High-resolution multispectral images of main-belt asteroid 3 Juno were taken at visible and near-IR wavelengths with the 100-inch telescope at Mount Wilson Observatory equipped with an adaptive optics system. The images show spectral features that may represent a large relatively recent impact that deeply excavated the coarse-grained olivine-pyroxene-rich crust of the asteroid. (C) 2003 Elsevier Science (USA). All rights reserved. C1 NYU, Earth & Environm Sci Program, New York, NY 10003 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ N Dakota, Dept Space Studies, Grand Forks, ND 58202 USA. Mt Wilson Inst, Pasadena, CA 91106 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RP Rampino, MR (reprint author), NYU, Earth & Environm Sci Program, 100 Washington Sq E Room 1009, New York, NY 10003 USA. NR 18 TC 8 Z9 8 U1 3 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 J9 ICARUS JI Icarus PD MAY PY 2003 VL 163 IS 1 BP 135 EP 141 DI 10.1016/S0019-1035(03)00049-6 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 681VN UT WOS:000183056400009 ER PT J AU Lamy, P Biesecker, DA Groussin, O AF Lamy, P Biesecker, DA Groussin, O TI SOHO/ILASCO observation of an outburst of Comet 2P/Encke at its 2000 perihelion passage SO ICARUS LA English DT Article DE comets; 2P/Encke; nucleus; photometry ID NUCLEUS; ASYMMETRY; SOLAR; SWAN; SOHO AB Comet 2P/Encke was observed with the SOHO/LASCO C2 and C3 coronagraphs over a time interval of 11 days, starting 4 days before its September 2000 perihelion passage and through several broadband visible filters. The lightcurve reveals an outburst which started 4.9 days after perihelion, with the brightness of the coma increasing by 1.5 mag in just a few hours and progressively decreasing thereafter, probably going back to its original state in about 9 days. The color information indicates that an approximately solar color continuum was detected, implying that the observed signals were dominated by solar light scattered off submillimetric dust grains. We propose that the rapid migration of the subsolar point over the southern hemisphere during the perihelion passage activates one or several new active regions enriched in submillimetric grains, with the observed outburst corresponding to the initial blow-off of their mantle. This scenario is consistent with other observations and implies that the south polar region of the nucleus of 2P/Encke has very distinct properties. (C) 2003 Elsevier Science (USA). All rights reserved. C1 CNRS, Astron Spatiale Lab, F-13376 Marseille 12, France. NASA, Goddard Space Flight Ctr, L3 Com Analyt Corp, Greenbelt, MD 20771 USA. RP Lamy, P (reprint author), CNRS, Astron Spatiale Lab, BP8, F-13376 Marseille 12, France. NR 22 TC 9 Z9 9 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 2003 VL 163 IS 1 BP 142 EP 149 DI 10.1016/S0019-1035(03)00040-X PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 681VN UT WOS:000183056400010 ER PT J AU Chanover, NJ Anderson, CM McKay, CP Rannou, P Glenar, DA Hillman, JJ Blass, WE AF Chanover, NJ Anderson, CM McKay, CP Rannou, P Glenar, DA Hillman, JJ Blass, WE TI Probing Titan's lower atmosphere with acousto-optic tuning SO ICARUS LA English DT Article DE Titan; atmospheres; structure; radiative transfer; instrumentation ID ADAPTIVE OPTICS; AGGREGATE PARTICLES; AEROSOLS; SURFACE; CLOUDS; TROPOSPHERE; METHANE; IMAGES; HST; WAVELENGTH AB Narrow-band images of Titan were obtained in November 1999 with the NASA/GSFC- built acousto-optic imaging spectrometer (AIms) camera. This instrument utilizes a tunable filter element that was used within the 500- to 1050-nm range, coupled to a CCD camera system. The images were taken with the Mount Wilson 2.54-m (100 in.) Hooker telescope, which is equipped with a natural guide star adaptive optics system. We observed Titan at 830 and 890 nm and at a series of wavelengths across the 940-nm window in Titan's atmosphere where the methane opacity is relatively low. We determined the absolute reflectivity (I/F) of Titan and fit the values at 940 nm to a Minnaert function at Titan's equator and at -30degrees latitude (closer to the subsolar point) and obtained average values for the Minnaert limb-darkening slope, k, of 0.661 +/- 0.007 and 0.775 +/- 0.018, respectively. Comparison with models suggests that the equatorial value of k is consistent with rain removal of haze in the lower atmosphere. The higher value of k at -30degrees is consistent with the southern hemisphere being brighter than the equator. However, the fits are not unique. The data and models at 890 are consistent with no limb brightening or darkening at this wavelength either at the equator or at -30degrees. (C) 2003 Elsevier Science (USA). All rights reserved. C1 New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Univ Paris 06, Serv Aeron, F-75252 Paris, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. RP Chanover, NJ (reprint author), New Mexico State Univ, Dept Astron, Box 30001-Dept 4500, Las Cruces, NM 88003 USA. RI Blass, William/A-2792-2008; Anderson, Carrie/C-8097-2012; RANNOU, Pascal/I-9059-2012 NR 47 TC 22 Z9 22 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 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2003 VL 163 IS 1 BP 150 EP 163 DI 10.1016/S0019-1035(03)00075-7 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 681VN UT WOS:000183056400011 ER PT J AU Mosqueira, I Estrada, PR AF Mosqueira, I Estrada, PR TI Formation of the regular satellites of giant planets in an extended gaseous nebula I: subnebula model and accretion of satellites SO ICARUS LA English DT Review DE Galilean satellites; gas dynamics; formation of satellites; protoplanetary disks ID PRIMORDIAL SOLAR NEBULA; ANGULAR-MOMENTUM TRANSPORT; ROSSBY-WAVE INSTABILITY; PROTOSTELLAR DISKS; GAS DRAG; PROTOPLANETARY DISKS; GALILEAN SATELLITES; NUMERICAL-MODELS; DENSITY WAVES; EVOLUTION AB We model the subnebulae of Jupiter and Saturn wherein satellite accretion took place. We expect each giant planet subnebula to be composed of an optically thick (given gaseous opacity) inner region inside of the planet's centrifugal radius (where the specific angular momentum of the collapsing giant planet gaseous envelope achieves centrifugal balance, located at r(C)(J) similar to 15R(J) for Jupiter and r(C)(S) similar to 22R(S) for Saturn) and an optically thin, extended outer disk out to a fraction of the planet's Roche-lobe (RH), which we choose to be similar toR(H)/5 (located at similar to150 R-J near the inner irregular satellites for Jupiter, and similar to200 R-S near Phoebe for Saturn). This places Titan and Ganymede in the inner disk, Callisto and Iapetus in the outer disk, and Hyperion in the transition region. The inner disk is the leftover of the gas accreted by the protoplanet. The outer disk may result from the nebula gas flowing into the protoplanet during the time of giant planet gap-opening (or cessation of gas accretion). For the sake of specificity, we use a solar composition "minimum mass" model to constrain the gas densities of the inner and outer disks of Jupiter and Saturn (and also Uranus). Our model has Ganymede at a subnebula temperature of similar to250 K and Titan at similar to100 K. The outer disks of Jupiter and Saturn have constant temperatures of 130 and 90 K, respectively. Our model has Callisto forming in a time scale similar to10(6) years, Iapetus in 10(6)-10(7) years, Ganymede in 10(3)-10(4) years, and Titan in 10(4)-10(5) years. Callisto takes much longer to form than Ganymede because it draws materials from the extended, low density portion of the disk; its accretion time scale is set by the inward drift times of satellitesimals with sizes 300-500 km from distances similar to100R(J). This accretion history may be consistent with a partially differentiated Callisto with a similar to300-km clean ice outer shell overlying a mixed ice and rock-metal interior as suggested by Anderson et al. (2001), which may explain the Ganymede-Callisto dichotomy without resorting to fine-tuning poorly known model parameters. It is also possible that particulate matter coupled to the high specific angular momentum gas flowing through the gap after giant planet gap-opening, capture of heliocentric planetesimals by the extended gas disk, or ablation of planetesimals passing through the disk contributes to the solid content of the disk and lengthens the time scale for Callisto's formation. Furthermore, this model has Hyperion forming just outside Saturn's centrifugal radius, captured into resonance by proto-Titan in the presence of a strong gas density gradient as proposed by Lee and Peale (2000). While Titan may have taken significantly longer to form than Ganymede, it still formed fast enough that we would expect it to be fully differentiated. In this sense, it is more like Ganymede than like Callisto (Saturn's analog of Callisto, we expect, is Iapetus). An alternative starved disk model whose satellite accretion time scale for all the regular satellites is set by the feeding of planetesimals or gas from the planet's Roche-lobe after gap-opening is likely to imply a long accretion time scale for Titan with small quantities of NH3 present, leading to a partially differentiated (Callisto-like) Titan. ne Cassini mission may resolve this issue conclusively. We briefly discuss the retention of elements more volatile than H2O as well as other issues that may help to test our model. (C) 2003 Elsevier Science (USA). All rights reserved. C1 NASA Ames, SETI Inst, Stanford, CA 94305 USA. Cornell Univ, Dept Astron, Ithaca, NY 14850 USA. RP Mosqueira, I (reprint author), NASA Ames, SETI Inst, Mail Stop 245-3, Stanford, CA 94305 USA. NR 127 TC 106 Z9 108 U1 0 U2 5 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2003 VL 163 IS 1 BP 198 EP 231 DI 10.1016/S0019-1035(03)00076-9 PG 34 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 681VN UT WOS:000183056400015 ER PT J AU Mosqueira, I Estrada, PR AF Mosqueira, I Estrada, PR TI Formation of the regular satellites of giant planets in an extended gaseous nebula II: satellite migration and survival SO ICARUS LA English DT Article DE Galilean satellites; gas dynamics; formation of satellites; protoplanetary disks ID SOLAR NEBULA; LINDBLAD RESONANCES; 3-DIMENSIONAL WAVES; ORBITAL MIGRATION; ACCRETION DISKS; PROPAGATION; EVOLUTION; PROTOPLANETS; EXCITATION; TORQUES AB For a satellite to survive in the disk the time scale of satellite migration must be longer than the time scale for gas dissipation. For large satellites (similar to1000 km) migration is dominated by the gas tidal torque. We consider the possibility that the redistribution of gas in the disk due to the tidal torque of a satellite with mass larger than the inviscid critical mass causes the satellite to stall and open a gap (W.R. Ward, 1997, Icarus 26, 261-281). We adapt the inviscid critical mass criterion to include gas drag, and m-dependent nonlocal deposition of angular momentum. We find that such a model holds promise of explaining the survival of satellites in the subnebula, the mass versus distance relationship apparent in the saturnian and uranian satellite systems, the concentration of mass in Titan, and the observation that the satellites of Jupiter get rockier closer to the planet whereas those of Saturn become increasingly icy. It is also possible that either weak turbulence (close to the planet) or gap-opening satellite tidal torque removes gas on a similar time scale (10(4)-10(5) years) as the orbital decay time of midsized (200-700 km) regular satellites forming in the inner disk (inside the centrifugal radius (I. Mosqueira and P.R. Estrada, 2003, Ikarus, this issue)). We argue that Saturn's satellite system bridges the gap between those of Jupiter and Uranus by combining the formation of a Galilean-sized satellite in a gas optically thick subnebula with a strong temperature gradient, and the formation of smaller satellites, closer to the planet, in a disk with gas optical depth less than or equal to1, and a weak temperature gradient. Using an optically thick inner disk (given gaseous opacity), and an extended, quiescent, optically thin outer disk, we show that there are regions of the disk of small net tidal torque (even zero) where satellites (Iapetus-sized or larger) may stall far from the planet. For our model these outer regions of small net tidal torque correspond roughly to the locations of Callisto and Iapetus. Though the precise location depends on the (unknown) size of the transition region between the inner and outer disks, the result that Saturn's is found much farther out (at similar to3r(c)(S), where r(c)(S) is Saturn's centrifugal radius) than Jupiter's (at similar to 2r(c)(J), where r(c)(J) is Jupiter's centrifugal radius) is mostly due to Saturn's less massive outer disk and larger Hill radius. However, despite the large separation between Ganymede and Callisto and Titan and Iapetus, the long formation and migration time scales for Callisto and Iapetus (I. Mosqueira and P.R. Estrada, 2003, Icarus, this issue) makes it possible (depending on the details of the damping of acoustic waves) that the tidal torque of Ganymede and Titan clears the gas disk out to their location, thus stranding Callisto and Iapetus far from the planet. Either way, our model provides an explanation for the presence of regular satellites outside the centrifugal radii of Jupiter and Saturn, and the absence of such a satellite for Uranus. (C) 2003 Elsevier Science (USA). All rights reserved. C1 NASA Ames, SETI Inst, Stanford, CA 94305 USA. Cornell Univ, Dept Astron, Ithaca, NY 14850 USA. RP Mosqueira, I (reprint author), NASA Ames, SETI Inst, Mail Stop 245-3, Stanford, CA 94305 USA. NR 35 TC 55 Z9 57 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 2003 VL 163 IS 1 BP 232 EP 255 DI 10.1016/S0019-1035(03)00077-0 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 681VN UT WOS:000183056400016 ER PT J AU Sromovsky, LA Fry, PM Limaye, SS Baines, KH AF Sromovsky, LA Fry, PM Limaye, SS Baines, KH TI The nature of Neptune's increasing brightness: evidence for a seasonal response SO ICARUS LA English DT Article DE Neptune; Neptune, atmosphere; meteorology; atmospheres, dynamics ID COORDINATED 1996 HST; ATMOSPHERIC CIRCULATION AB Hubble Space Telescope (HST) observations in August 2002 show that Neptune's disk-averaged reflectivity increased significantly since 1996, by 3.2 +/- 0.3% at 467 nm, 5.6 +/- 0.6% at 673 nm, and 40 +/- 4% in the 850-1000 nm band, which mainly results from dramatic brightness increases in restricted latitude bands. When 467-nm HST observations from 1994 to 2002 are added to the 472-nm ground-based results of Lockwood and Thompson (2002, Icarus 56, 37-51), the combined disk-averaged variation from 1972 to 2002 is consistent with a simple seasonal model having a hemispheric response delay relative to solar forcing of similar to30 years (similar to73% of a full season). (C) 2003 Elsevier Science (USA). All rights reserved. C1 Univ Wisconsin, Ctr Space Sci & Engn, Madison, WI 53706 USA. Jet Prop Lab, Pasadena, CA 91109 USA. RP Sromovsky, LA (reprint author), Univ Wisconsin, Ctr Space Sci & Engn, 1225 W Dayton St, Madison, WI 53706 USA. EM larry.sromovsky@ssec.wisc.edu NR 20 TC 16 Z9 16 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 2003 VL 163 IS 1 BP 256 EP 261 DI 10.1016/S0019-1035(03)00069-1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 681VN UT WOS:000183056400017 ER PT J AU Piprek, J Ning, CZ Wunsche, HJ Yu, SF AF Piprek, J Ning, CZ Wunsche, HJ Yu, SF TI Introduction to the issue on optoelectronic device simulation SO IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS LA English DT Editorial Material C1 Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Inst Phys, D-12489 Berlin, Germany. Nanyang Technol Univ, Sch Elect & Elect Engn, Singapore 639798, Singapore. RP Piprek, J (reprint author), Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA. RI Piprek, Joachim/A-7627-2012 OI Piprek, Joachim/0000-0002-4002-1629 NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1077-260X J9 IEEE J SEL TOP QUANT JI IEEE J. Sel. Top. Quantum Electron. PD MAY-JUN PY 2003 VL 9 IS 3 BP 685 EP 687 DI 10.1109/JSTQE.2003.821632 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 750LW UT WOS:000186993000001 ER PT J AU Wood, WA Kleb, WL AF Wood, WA Kleb, WL TI Exploring XP for scientific research SO IEEE SOFTWARE LA English DT Article AB Can we successfully apply XP in a scientific research context? A pilot project at the NASA Langley Research Center tested XP's applicability in this context. Because the cultural environment at a government research center differs from the customer-centric business view, eight of XP's 12 practices seemed incompatible with the existing research culture. Despite initial awkwardness, the authors determined that XP can function in situations for which it appears to be ill suited. C1 NASA, Aerothermodynam Branch, Langley Res Ctr, Hampton, VA 23665 USA. RP Wood, WA (reprint author), NASA, Aerothermodynam Branch, Langley Res Ctr, Hampton, VA 23665 USA. NR 7 TC 36 Z9 36 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0740-7459 J9 IEEE SOFTWARE JI IEEE Softw. PD MAY-JUN PY 2003 VL 20 IS 3 BP 30 EP + DI 10.1109/MS.2003.1196317 PG 8 WC Computer Science, Software Engineering SC Computer Science GA 670UK UT WOS:000182427400022 ER PT J AU Turmon, M Granat, R Katz, DS Lou, JZ AF Turmon, M Granat, R Katz, DS Lou, JZ TI Tests and tolerances for high-performance software-implemented fault detection SO IEEE TRANSACTIONS ON COMPUTERS LA English DT Article DE algorithm-based fault tolerance; result checking; error analysis; aerospace; parallel numerical algorithms AB We describe and test a software approach to fault detection in common numerical algorithms. Such result checking or algorithm-based fault tolerance (ABFT) methods may be used, for example, to overcome single-event upsets in computational hardware or to detect errors in complex, high-efficiency implementations of the algorithms. Following earlier work, we use checksum methods to validate results returned by a numerical subroutine operating subject to unpredictable errors in data. We consider common matrix and Fourier algorithms which return results satisfying a necessary condition having a linear form; the checksum tests compliance with this condition. We discuss the theory and practice of setting numerical tolerances to separate errors caused by a fault from those inherent in finite-precision floating-point calculations. We concentrate on comprehensively defining and evaluating tests having various accuracy/computational burden tradeoffs, and we emphasize average-case algorithm behavior rather than using worst-case upper bounds on error. C1 Jet Prop Lab, Data Understanding Syst Grp, Pasadena, CA 91109 USA. Jet Prop Lab, Parallel Applicat Technol Grp, Pasadena, CA 91109 USA. RP Turmon, M (reprint author), Jet Prop Lab, Data Understanding Syst Grp, M-S 126-347,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM michael.turmon@jpl.nasa.gov; robert.granat@jpl.nasa.gov; Daniel.S.Katz@jpl.nasa.gov; john.z.lou@jpl.nasa.gov OI Katz, Daniel S./0000-0001-5934-7525 NR 18 TC 7 Z9 7 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 0018-9340 EI 1557-9956 J9 IEEE T COMPUT JI IEEE Trans. Comput. PD MAY PY 2003 VL 52 IS 5 BP 579 EP 591 DI 10.1109/TC.2003.1197125 PG 13 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 672LJ UT WOS:000182521800004 ER PT J AU Liu, J Kuga, Y Ishimaru, A Pi, XQ Freeman, A AF Liu, J Kuga, Y Ishimaru, A Pi, XQ Freeman, A TI Ionospheric effects on SAR imaging: A numerical study SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE ionospheric electromagnetic propagation; remote sensing; synthetic aperture radar (SAR) AB There has been an increasing interest in the use of spaceborne very high frequency ultra high frequency (VHF-UHF) synthetic aperture radar (SAR) for measuring forest biomass and for detecting underground facilities. The propagation characteristics of the low-frequency electromagnetic wave are severely affected by the ionosphere. Recently, Faraday rotation effects and SAR image degradation have been studied using an analytical model and a homogeneous ionosphere. In this paper, a numerical model is developed to investigate the SAR image degradation caused by an inhomogeneous ionosphere. Both horizontal and vertical structures of the ionosphere are considered in this model. Three different cases are studied. The first is a vertically homogenous ionosphere, where the simulation condition is the same as in the analytical study by Ishimaru and others. The second is a vertical profile, which is introduced using the Chapman formula. The ray-bending effect is added for the ionosphere with a layered structure. Finally, both the vertical profile in electron density and the horizontal gradient in total electron content are considered in the simulation. Simulation results show good agreement with the theoretical analysis under the same conditions of the ionosphere. When both horizontal and vertical structures and the inhomogeneity of the ionosphere are considered in the model, the simulation result shows further image degradation and shift caused by the ray-bending effect. The simulation results also show the strong frequency dependence of the SAR image resolution. C1 Univ Washington, Dept Elect Engn, Seattle, WA 98195 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liu, J (reprint author), Univ Washington, Dept Elect Engn, Seattle, WA 98195 USA. NR 11 TC 48 Z9 59 U1 1 U2 6 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 2003 VL 41 IS 5 BP 939 EP 947 DI 10.1109/TGRS.2003.811813 PN 1 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 692PT UT WOS:000183670000001 ER PT J AU Gloersen, P Huang, N AF Gloersen, P Huang, N TI Comparison of interannual intrinsic modes in hemispheric sea ice covers and other geophysical parameters SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE geophysical measurements; microwave measurements; remote sensing; sea; sea ice ID TERRESTRIAL FREE OSCILLATIONS; ANTARCTIC CIRCUMPOLAR WAVE; TAPER SPECTRAL-ANALYSIS; TIME-SERIES; HILBERT SPECTRUM; TEMPERATURE; SEASONALITY; PRESSURE; BEHAVIOR; EXTENTS AB Recent papers have described 18-year trends and interannual oscillations in the Arctic and Antarctic sea ice extents, areas, and enclosed open water areas based on newly formulated 18.2-year ice concentration time series. They were obtained by fine-tuning the sea ice algorithm tie points individually for each of the four sensors used to acquire the data. In this paper, these analyses are extended to an examination of the intrinsic modes of these time series, obtained by means of empirical mode decomposition, which handles both nonstationary and nonlinear data as found in these time series, unlike filtering techniques based on Fourier analysis. Our analysis centers on periodicities greater than one year. Quasi-biennial and quasi-quadrennial oscillations similar to those observed earlier with a multitaper-filtered Fourier analysis technique were also observed here. The intrinsic modes described here feature frequency as well as amplitude modulation within their respective frequency bands. The slowest varying mode in the Antarctic sea ice cover has slightly less than a full period during this 18.2-year time period, but the change in sign of its curvature hints at a modal period of about 19 years, with important implications for the trend analyses published earlier. C1 NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. RP Gloersen, P (reprint author), NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. NR 36 TC 38 Z9 51 U1 2 U2 8 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 2003 VL 41 IS 5 BP 1062 EP 1074 DI 10.1109/TGRS.2003.811814 PN 1 PG 13 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 692PT UT WOS:000183670000014 ER PT J AU Ansar, A Daniilidis, K AF Ansar, A Daniilidis, K TI Linear pose estimation from points or lines SO IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE LA English DT Article DE pose estimation; exterior orientation; absolute orientation; camera localization ID CLOSED-FORM SOLUTION; ORIENTATION; IMAGES AB Estimation of camera pose from an image of n points or lines with known correspondence is a thoroughly studied problem in computer vision. Most solutions are iterative and depend on nonlinear optimization of some geometric constraint, either on the world coordinates or on the projections to the image plane. For real-time applications, we are interested in linear or closed-form solutions free of initialization. We present a general framework which allows for a novel set of linear solutions to the pose estimation problem for both n points and n lines. We then analyze the sensitivity of our solutions to image noise and show that the sensitivity analysis can be used as a conservative predictor of error for our algorithms. We present a number of simulations which compare our results to two other recent linear algorithms, as well as to iterative approaches. We conclude with tests on real imagery in an augmented reality setup. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Penn, GRASP Lab, Philadelphia, PA 19104 USA. RP Ansar, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 28 TC 168 Z9 197 U1 0 U2 20 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0162-8828 J9 IEEE T PATTERN ANAL JI IEEE Trans. Pattern Anal. Mach. Intell. PD MAY PY 2003 VL 25 IS 5 BP 578 EP 589 DI 10.1109/TPAMI.2003.1195992 PG 12 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 669FY UT WOS:000182342300004 ER PT J AU Iannello, C Luo, SG Batarseh, I AF Iannello, C Luo, SG Batarseh, I TI Small-signal and transient analysis of a full-bridge, zero-current-switched PWM converter using an average model SO IEEE TRANSACTIONS ON POWER ELECTRONICS LA English DT Article DE FB-ZVS converter; high voltage; PSPICE; PWM; steady-state analysis; switched-circuit simulation; ZCS ID CONDUCTION MODE AB This paper presents a detailed small-signal and transient analysis of a full bridge zero-current-switched (FB-ZCS) PWM converter designed for high voltage, high power applications using an average model. The development shows the model follows directly from the converter's steady-state analysis and is produced by inspection of the converter's instantaneous waveforms. The method used in model development can be extended to other topologies that are not easily modeled by conventional methods. The derived model is implemented in a PSPICE subcircuit and used to produce the small-signal and transient characteristics of the converter. Results obtained in the analysis of the high voltage and high power design example are validated by comparison to the actual, switched-circuit simulations. C1 NASA, Shuttle Elect Power Syst Grp, Kennedy Space Ctr, FL 32899 USA. Univ Cent Florida, Dept Elect & Comp Engn, Orlando, FL 32816 USA. Artesyn Technol, Boca Raton, FL 33432 USA. RP Iannello, C (reprint author), NASA, Shuttle Elect Power Syst Grp, Kennedy Space Ctr, FL 32899 USA. EM batarseh@mail.ucf.edu NR 13 TC 16 Z9 18 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0885-8993 J9 IEEE T POWER ELECTR JI IEEE Trans. Power Electron. PD MAY PY 2003 VL 18 IS 3 BP 793 EP 801 DI 10.1109/TPEL.2003.810847 PG 9 WC Engineering, Electrical & Electronic SC Engineering GA 677ZV UT WOS:000182840700010 ER PT J AU Hoover, RB Pikuta, EV Bej, AK Marsic, D Whitman, WB Tang, J Krader, P AF Hoover, RB Pikuta, EV Bej, AK Marsic, D Whitman, WB Tang, J Krader, P TI Spirochaeta americana sp nov., a new haloalkallphilic, obligately anaerobic spirochaete isolated from soda Mono Lake in California SO INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY LA English DT Article ID SP-N; THERMOPHILIC BACTERIUM; RENATURATION RATES; BAJACALIFORNIENSIS; PHYSIOLOGY; PROTEIN; SPRINGS; DNA AB A novel, obligately anaerobic, mesophilic, haloalkaliphilic spirochaete, strain ASpG1(T), was isolated from sediments of the alkaline, hypersaline Mono Lake in California, USA. Cells of the Gram-negative strain were motile and spirochaete-shaped with sizes of 0.2-0.22 x 8-18 mum. Growth of the strain was observed between 10 and 44 degreesC (optimum 37 degreesC), in 2-12 % (w/v) NaCl (optimum 3 % NaCl) and between pH 8 and 10.5 (optimum pH 9.5). The novel strain was strictly alkaliphilic, required high concentrations of carbonates in the medium and was capable of utilizing D-glucose, fructose, maltose, sucrose, starch and D-mannitol. End products of glucose fermentation were H-2, acetate, ethanol and formate. Strain ASpG1(T) was resistant to kanamycin and rifampicin, but sensitive to gentamicin, tetracycline and chloramphenicol. The G + C content of its DNA was 58.5 mol%. DNA-DNA hybridization analysis of strain ASpG1(T) with its most closely related species, Spirochaeta alkalica Z-7491(T), revealed a hybridization value of only 48.7%. On the basis of its physiological and molecular properties, strain ASpG1(T) appears to represent a novel species of the genus Spirochaeta, for which the name Spirochaeta americana is proposed (type strain ASpG1(T) = ATCC BAA-392(T) = DSM 14872(T)). C1 NASA NSSTC, Huntsville, AL 35805 USA. Univ Alabama, Dept Biol, Birmingham, AL 35294 USA. Univ Alabama, Struct Biol Lab, Huntsville, AL 35899 USA. Univ Georgia, Dept Microbiol, Athens, GA 30602 USA. Amer Type Culture Collect, Manassas, VA USA. RP Hoover, RB (reprint author), NASA NSSTC, SD-50,320 Sparkman Dr, Huntsville, AL 35805 USA. RI Marsic, Damien/A-1087-2009 OI Marsic, Damien/0000-0003-0847-8095 NR 39 TC 46 Z9 47 U1 0 U2 4 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 2003 VL 53 BP 815 EP 821 DI 10.1099/ijs.0.02535-0 PN 3 PG 7 WC Microbiology SC Microbiology GA 685MQ UT WOS:000183268200027 PM 12807206 ER PT J AU Takai, K Kobayashi, H Nealson, KH Horikoshi, K AF Takai, K Kobayashi, H Nealson, KH Horikoshi, K TI Sulfurihydrogenibium subterraneum gen. nov., sp nov., from a subsurface hot aquifer SO INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY LA English DT Article ID HYDROGEN-OXIDIZING BACTERIUM; YELLOWSTONE-NATIONAL-PARK; HYDROTHERMAL VENTS; MICROBIAL MATS; DIVERSITY; COMMUNITY; AQUIFICALES; ACIDOPHILUS; SPRINGS; GROWTH AB A polyphasic taxonomic study was performed on a novel facultatively anaerobic, hydrogen- or sulfur/thiosulfate-oxidizing, thermophilic chemolithoautotroph recently isolated from subsurface hot aquifer water in a Japanese gold mine. The cells were straight to slightly curved rods, with a single polar flagellum. Growth was observed at 40-70 degreesC (optimum 60-65 degreesC 80 min doubling time) and at pH 6.4-8.8 (optimum pH 7.5). The isolate was unable to use complex organic compounds, carbohydrates, amino acids or organic acids as sole energy and carbon sources. The G + C content of the genomic DNA was 31.3 mol%. Phylogenetic analysis based on 16S rDNA sequences indicated that the isolate was closely related to an uncultivated group of micro-organisms within the order Aquificales obtained from Icelandic and Japanese hot spring microbial mats, but distantly related to previously identified genera of the Aquificales such as Persephonella, Aquifex and Hydrogenobacter. The name Sulfurihydrogenibium subterraneum gen. nov., sp. nov. is proposed for this novel species; the type strain is HGMK1(T) (=JCM 11477(T) = ATCC BAA-562(T) = DSM 15120(T)). C1 Japan Marine Sci & Technol Ctr, Subground Animalcule Retrieval SUGAR Project, Yokosuka, Kanagawa 2370061, Japan. Japan Marine Sci & Technol Ctr, DEEPSTAR Grp, Frontier Res Syst Extremopilles, Yokosuka, Kanagawa 2370061, Japan. Univ So Calif, Dept Earth Sci, Los Angeles, CA 90089 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Takai, K (reprint author), Japan Marine Sci & Technol Ctr, Subground Animalcule Retrieval SUGAR Project, 2-15 Natsushima Cho, Yokosuka, Kanagawa 2370061, Japan. EM kent@jamstec.go.jp NR 25 TC 55 Z9 57 U1 0 U2 5 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 2003 VL 53 BP 823 EP 827 DI 10.1099/ijs.0.02506-0 PN 3 PG 5 WC Microbiology SC Microbiology GA 685MQ UT WOS:000183268200028 PM 12807207 ER PT J AU Takai, K Kobayashi, H Nealson, KH Horikoshi, K AF Takai, K Kobayashi, H Nealson, KH Horikoshi, K TI Deferribacter desulfuricans sp nov., a novel sulfur-, nitrate- and arsenate-reducing thermophile isolated from a deep-sea hydrothermal vent SO INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY LA English DT Article ID HYPERTHERMOPHILIC ARCHAEON; PETROLEUM RESERVOIRS; OIL-RESERVOIR; GEN. NOV.; BACTERIUM; ARCHAEBACTERIUM; MICROORGANISMS; HYBRIDIZATION; CULTURE; CHIMNEY AB A novel anaerobic, heterotrophic thermophile was isolated from a deep-sea hydrothermal vent chimney at the Suiyo Seamount in the lzu-Bonin Arc, Japan. The cells were bent, flexible rods, with a single polar flagellum. Growth was observed between 40 and 70 degreesC (optimum temperature: 60-65 degreesC; doubling time, 40 min) and between pH 5.0 and 7.5 (optimum PH 6.5). The isolate was a strictly anaerobic heterotroph capable of using complex organic compounds (yeast extract, tryptone, peptone, casein and Casamino acids), ethanol and various organic acids as energy and carbon sources. Hydrogen could serve as a supplementary energy source. Elemental sulfur (SO), nitrate or arsenate was required for growth as an electron acceptor. The G + C content of the genomic DNA was 38.6 mol%. Phylogenetic analysis based on 16S rDNA sequences indicated that isolate SSM1(T) is closely related to Deferribacter thermophilus BMA(T) (98.1 %). However, the novel isolate could be clearly differentiated from D. thermophilus BMA T on the basis of its physiological and genetic properties. The name Deferribacter desulfuricans sp. nov. (type strain SSM1(T)= JCM 11476(T) = DSM 14783(T)) is proposed. C1 Japan Marine Sci & Technol Ctr, Subground Animalcule Retrieval SUGAR Project, Yokosuka, Kanagawa 2370061, Japan. Japan Marine Sci & Technol Ctr, DEEP STAR Grp, Yokosuka, Kanagawa 2370061, Japan. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Takai, K (reprint author), Japan Marine Sci & Technol Ctr, Subground Animalcule Retrieval SUGAR Project, 2-15 Natsushima Cho, Yokosuka, Kanagawa 2370061, Japan. EM kent@jamstec.go.jp NR 40 TC 63 Z9 66 U1 1 U2 17 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 2003 VL 53 BP 839 EP 846 DI 10.1099/ijs.0.02479-0 PN 3 PG 8 WC Microbiology SC Microbiology GA 685MQ UT WOS:000183268200031 PM 12807210 ER PT J AU Ansari, RR Manuel, FK Suh, KI King, JF Messer, RK Moret, F AF Ansari, RR Manuel, FK Suh, KI King, JF Messer, RK Moret, F TI Choroidal blood flow measurements in zero gravity (space-like) environment using laser-Doppler flowmetry SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract CT Annual Meeting of the Association-for-Research-in-Vision-and-Ophthalmology CY MAY, 2003 CL FT LAUDERDALE, FLORIDA SP Assoc Res Vis & Ophthalmol C1 NASA, Glenn Res Ctr, Cleveland, OH USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NASA, OAI, Glenn Res Ctr, Cleveland, OH USA. NASA, QSS, Glenn Res Ctr, Cleveland, OH USA. NASA, NCMR, Glenn Res Ctr, Cleveland, OH USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASSOC RESEARCH VISION OPHTHALMOLOGY INC PI ROCKVILLE PA 12300 TWINBROOK PARKWAY, ROCKVILLE, MD 20852-1606 USA SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAY PY 2003 VL 44 SU 1 MA 960 BP U263 EP U263 PG 1 WC Ophthalmology SC Ophthalmology GA 709CH UT WOS:000184606800936 ER PT J AU Clark, JI King, JF Seeberger, TM Ansari, RR AF Clark, JI King, JF Seeberger, TM Ansari, RR TI Non-invasive DLS detects the earliest stages of cataract and inhibition of lens opacification by pantethine in vivo SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract CT Annual Meeting of the Association-for-Research-in-Vision-and-Ophthalmology CY MAY 04, 2003 CL FT LAUDERDALE, FLORIDA SP Assoc Res Vis & Ophthalmol C1 Univ Washington, Sch Med, Seattle, WA USA. NASA, Glenn Res Ctr, Cleveland, OH USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASSOC RESEARCH VISION OPHTHALMOLOGY INC PI ROCKVILLE PA 12300 TWINBROOK PARKWAY, ROCKVILLE, MD 20852-1606 USA SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAY PY 2003 VL 44 SU 2 MA 3482 BP U259 EP U259 PG 1 WC Ophthalmology SC Ophthalmology GA 709CK UT WOS:000184607000944 ER PT J AU Fink, W Sadun, AA Clark, JB AF Fink, W Sadun, AA Clark, JB TI Worldwide accessible comprehensive visual field test & diagnosis system SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract CT Annual Meeting of the Association-for-Research-in-Vision-and-Ophthalmology CY MAY, 2003 CL FT LAUDERDALE, FLORIDA SP Assoc Res Vis & Ophthalmol C1 Univ So Calif, Keck Sch Med, Doheny Eye Inst, Los Angeles, CA 90089 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASSOC RESEARCH VISION OPHTHALMOLOGY INC PI ROCKVILLE PA 12300 TWINBROOK PARKWAY, ROCKVILLE, MD 20852-1606 USA SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAY PY 2003 VL 44 SU 1 MA 55 BP U7 EP U7 PG 1 WC Ophthalmology SC Ophthalmology GA 709CH UT WOS:000184606800029 ER PT J AU Leng, T Huie, P Bilbao, KV Blumenkranz, MS Loftus, DJ Fishman, HA AF Leng, T Huie, P Bilbao, KV Blumenkranz, MS Loftus, DJ Fishman, HA TI Carbon nanotube bucky paper as an artificial support membrane and Bruch's membrane patch in subretinal RPE and IPE transplantation SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract CT Annual Meeting of the Association-for-Research-in-Vision-and-Ophthalmology CY MAY, 2003 CL FT LAUDERDALE, FLORIDA SP Assoc Res Vis & Ophthalmol C1 Stanford Univ, Stanford, CA 94305 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 5 Z9 5 U1 0 U2 3 PU ASSOC RESEARCH VISION OPHTHALMOLOGY INC PI ROCKVILLE PA 12300 TWINBROOK PARKWAY, ROCKVILLE, MD 20852-1606 USA SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAY PY 2003 VL 44 SU 1 MA 481 BP U97 EP U97 PG 1 WC Ophthalmology SC Ophthalmology GA 709CH UT WOS:000184606800457 ER PT J AU Wang, K Loftus, D Leng, T Harris, JS Fishman, H AF Wang, K Loftus, D Leng, T Harris, JS Fishman, H TI Carbon nanotubes as microelectrodes for a retinal prosthesis SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract CT Annual Meeting of the Association-for-Research-in-Vision-and-Ophthalmology CY MAY 04, 2003 CL FT LAUDERDALE, FLORIDA SP Assoc Res Vis & Ophthalmol C1 Stanford Univ, Stanford, CA 94305 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 3 Z9 3 U1 0 U2 1 PU ASSOC RESEARCH VISION OPHTHALMOLOGY INC PI ROCKVILLE PA 12300 TWINBROOK PARKWAY, ROCKVILLE, MD 20852-1606 USA SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAY PY 2003 VL 44 SU 2 MA 5054 BP U702 EP U702 PG 1 WC Ophthalmology SC Ophthalmology GA 709CK UT WOS:000184607002513 ER PT J AU Greenblatt, D Wygnanski, I AF Greenblatt, D Wygnanski, I TI Effect of leading-edge curvature on airfoil separation control SO JOURNAL OF AIRCRAFT LA English DT Article ID DYNAMIC STALL CONTROL; PERIODIC EXCITATION; OSCILLATORY CONTROL; FLOW AB Separation control on NACA 0012 and NACA 0015 airfoils was compared under incompressible conditions, using leading-edge periodic excitation, in order to assess the effect of leading-edge curvature. Both lift and moment coefficients were considered to compare and analyse control effectiveness. In contrast to the relatively mild NACA 0015 trailing-edge stall, NACA 0012 stall was dominated by a leading-edge bubble-bursting mechanism that gave rise to alternating intervals of partial attachment and separation, but with no regular frequency. Low-amplitude excitation downstream of the bubble enhanced poststall lift and significantly attenuated the associated unsteadiness. In general, larger momentum coefficients were required for NACA 0012 separation control due to the large centrifugal acceleration of the flow around the leading edge. Because of the different stalling characteristics, relatively high- and low-excitation frequencies were effective for the NACA 0012 and NACA 0015 airfoils, respectively. However, the combination of high-excitation amplitudes with relatively low frequencies was effective on the NACA 0012, and this was believed to be associated with the large harmonic content of the evolving perturbations. C1 Tel Aviv Univ, Dept Fluid Mech & Heat Transfer, IL-69978 Tel Aviv, Israel. Univ Arizona, Tucson, AZ 85721 USA. RP Greenblatt, D (reprint author), NASA, Langley Res Ctr, Flow Phys & Control Branch, Mail Stop 170,1 E Reid St, Hampton, VA 23681 USA. NR 31 TC 21 Z9 21 U1 2 U2 11 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 2003 VL 40 IS 3 BP 473 EP 481 DI 10.2514/2.3142 PG 9 WC Engineering, Aerospace SC Engineering GA 689BR UT WOS:000183472200007 ER PT J AU Newman, JC Whitfield, DL Anderson, WK AF Newman, JC Whitfield, DL Anderson, WK TI Step-size independent approach for multidisciplinary sensitivity analysis SO JOURNAL OF AIRCRAFT LA English DT Article ID UNSTRUCTURED GRIDS; AERODYNAMIC DESIGN; COMPLEX-VARIABLES; TURBULENT FLOWS; OPTIMIZATION; DERIVATIVES; ALGORITHM; EQUATIONS AB A multidisciplinary sensitivity analysis technique based on a complex Taylor series expansion method is implemented. This technique is shown to be independent of step-size selection as it pertains to cancellation errors. The primary focus of this research is to validate a new aero-structural analysis and sensitivity analysis procedure. This validation consists of comparing computed and experimental data obtained for an aeroelastic research wing. Because the aero-structural analysis procedure has the complex variable modifications already included into the software, sensitivity derivatives are automatically computed. Other than for design purposes, sensitivity derivatives can be used for predicting the solution at nearby conditions. The use of sensitivity derivatives for predicting the aero-structural characteristics of this configuration is demonstrated and compared with experimental measurements. C1 Mississippi State Univ, Dept Aerosp Engn, Mississippi State, MS 39762 USA. Univ Tennessee, Chattanooga, TN 37403 USA. NASA, Langley Res Ctr, Aerodynam & Acoust Methods Branch, Hampton, VA 23681 USA. RP Newman, JC (reprint author), Mississippi State Univ, Dept Aerosp Engn, Mississippi State, MS 39762 USA. NR 60 TC 18 Z9 18 U1 1 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 2003 VL 40 IS 3 BP 566 EP 573 PG 8 WC Engineering, Aerospace SC Engineering GA 689BR UT WOS:000183472200018 ER PT J AU Feltz, WF Smith, WL Howell, HB Knuteson, RO Woolf, H Revercomb, HE AF Feltz, WF Smith, WL Howell, HB Knuteson, RO Woolf, H Revercomb, HE TI Near-continuous profiling of temperature, moisture, and atmospheric stability using the atmospheric emitted radiance interferometer (AERI) SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID SEA-SURFACE TEMPERATURE; WATER-VAPOR; CLOUD; THUNDERSTORM; RETRIEVAL; ACCURACY AB The Department of Energy Atmospheric Radiation Measurement Program (ARM) has funded the development and installation of five ground-based atmospheric emitted radiance interferometer (AERI) systems at the Southern Great Plains (SGP) site. The purpose of this paper is to provide an overview of the AERI instrument, improvement of the AERI temperature and moisture retrieval technique, new profiling utility, and validation of high-temporal-resolution AERI-derived stability indices important for convective nowcasting. AERI systems have been built at the University of Wisconsin-Madison, Madison, Wisconsin, and deployed in the Oklahoma-Kansas area collocated with National Oceanic and Atmospheric Administration 404-MHz wind profilers at Lamont, Vici, Purcell, and Morris, Oklahoma, and Hillsboro, Kansas. The AERI systems produce absolutely calibrated atmospheric infrared emitted radiances at one-wavenumber resolution from 3 to 20 mum at less than 10-min temporal resolution. The instruments are robust, are automated in the field, and are monitored via the Internet in near-real time. The infrared radiances measured by the AERI systems contain meteorological information about the vertical structure of temperature and water vapor in the planetary boundary layer (PBL; 0-3 km). A mature temperature and water vapor retrieval algorithm has been developed over a 10-yr period that provides vertical profiles at less than 10-min temporal resolution to 3 km in the PBL. A statistical retrieval is combined with the hourly Geostationary Operational Environmental Satellite (GOES) sounder water vapor or Rapid Update Cycle, version 2, numerical weather prediction (NWP) model profiles to provide a nominal hybrid first guess of temperature and moisture to the AERI physical retrieval algorithm. The hourly satellite or NWP data provide a best estimate of the atmospheric state in the upper PBL; the AERI radiances provide the mesoscale temperature and moisture profile correction in the PBL to the large-scale GOES and NWP model profiles at high temporal resolution. The retrieval product has been named AERIplus because the first guess used for the mathematical physical inversion uses an optimal combination of statistical climatological, satellite, and numerical model data to provide a best estimate of the atmospheric state. The AERI physical retrieval algorithm adjusts the boundary layer temperature and moisture structure provided by the hybrid first guess to fit the observed AERI downwelling radiance measurement. This provides a calculated AERI temperature and moisture profile using AERI-observed radiances "plus" the best-known atmospheric state above the boundary layer using NWP or satellite data. AERIplus retrieval accuracy for temperature has been determined to be better than 1 K, and water vapor retrieval accuracy is approximately 5% in absolute water vapor when compared with well-calibrated radiosondes from the surface to an altitude of 3 km. Because AERI can monitor the thermodynamics where the atmosphere usually changes most rapidly, atmospheric stability tendency information is readily available from the system. High-temporal-resolution retrieval of convective available potential energy, convective inhibition, and PBL equivalent potential temperature theta(e) are provided in near-real time from all five AERI systems at the ARM SGP site, offering a unique look at the atmospheric state. This new source of meteorological data has shown excellent skill in detecting rapid synoptic and mesoscale meteorological changes within clear atmospheric conditions. This method has utility in nowcasting temperature inversion strength and destabilization caused by theta(e) advection. This high-temporal-resolution monitoring of rapid atmospheric destabilization is especially important for nowcasting severe convection. C1 Univ Wisconsin, Ctr Space Sci & Engn, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53715 USA. NASA, Div Atmospher Sci, Langley Res Ctr, Hampton, VA USA. RP Feltz, WF (reprint author), Univ Wisconsin, Ctr Space Sci & Engn, Cooperat Inst Meteorol Satellite Studies, 1225 W Dayton St,Rm 239, Madison, WI 53715 USA. NR 34 TC 72 Z9 72 U1 0 U2 10 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 2003 VL 42 IS 5 BP 584 EP 597 DI 10.1175/1520-0450(2003)042<0584:NPOTMA>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 671EK UT WOS:000182452200003 ER PT J AU Datta, S Jones, WL Roy, B Tokay, A AF Datta, S Jones, WL Roy, B Tokay, A TI Spatial variability of surface rainfall as observed from TRMM field campaign data SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID RADAR; VALIDATION AB The spatial variability of surface rainfall over 5- and 30-day time periods is observed, and it is found that the spatial decorrelation length of precipitation is comparable to the size of a single surface gauge network. The observed variability is found to affect radar-derived precipitation estimation, particularly if it is based on calibration using rain gauges. The radar subgrid-scale variability is also observed using some redundant and finer-scale gauge networks deployed during the Tropical Rainfall Measuring Mission ( TRMM) ground-validation field campaigns. Based upon statistical analysis and a point-based decision-making system, a best-suited spatial temporal filtering technique is suggested and, when applied to match radar data with any other surface observation, is found to reduce bias. C1 Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. Univ Cent Florida, Sch Elect Engn & Comp Sci, Orlando, FL 32816 USA. Sci Syst & Applicat Inc, Seabrook, MD USA. NASA, Mesoscale Proc Branch, Goddard Space Flight Ctr, Greenbelt, MD USA. RP Datta, S (reprint author), Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, ACIV Wing A,Rm 114,1000 Hilltop Circle, Baltimore, MD 21250 USA. NR 17 TC 18 Z9 18 U1 0 U2 2 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 2003 VL 42 IS 5 BP 598 EP 610 DI 10.1175/1520-0450(2003)042<0598:SVOSRA>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 671EK UT WOS:000182452200004 ER PT J AU Cruden, BA Rao, MVVS Sharma, SP Meyyappan, M AF Cruden, BA Rao, MVVS Sharma, SP Meyyappan, M TI Fourier-transform infrared and optical emission spectroscopy of CF4/O-2/Ar mixtures in an inductively coupled plasma SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID LASER-INDUCED FLUORESCENCE; NEUTRAL GAS TEMPERATURE; RADIO-FREQUENCY DISCHARGES; ABSORPTION-SPECTROSCOPY; ION ENERGY; REFERENCE CELL; CF4/O2 PLASMA; DENSITIES; ACTINOMETRY; DIAGNOSTICS AB Characterization of CF4/O-2/Ar inductively coupled plasmas by Fourier-transform infrared (FTIR) spectroscopy and optical emission spectroscopy (OES) in a Gaseous Electronics Conference reference cell has been carried out. Characterization was performed at three mixture compositions (80/10/10, 60/20/20, and 40/30/30), powers of 200 and 300 W and pressures between 10 and 50 mTorr. Quantitative estimates of CF4, CO, COF2, and SiF4 etch products are made via FTIR, while the OES combined with actinometry allows for qualitative characterization of conversion of CF4 to atomic C, CF, and C-2, and molecular oxygen to atomic oxygen. Qualitative measurements of F density and etch products Si and SiF are also made by OES. Results are explained by a combination of electron-impact dissociation and recombination processes. In the absence of significant capacitive coupling, etch species are believed to be formed primarily by window interactions with atomic F. Rotational temperatures are estimated by both FTIR and analysis of emission spectra. The FTIR technique tends to estimate temperatures several hundred K lower than OES data due to the absorption of colder gas species outside of the plasma. (C) 2003 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Eloret Corp, Moffett Field, CA 94035 USA. RP Cruden, BA (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 57 TC 15 Z9 15 U1 1 U2 28 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 2003 VL 93 IS 9 BP 5053 EP 5062 DI 10.1063/1.1563819 PG 10 WC Physics, Applied SC Physics GA 668MA UT WOS:000182296700013 ER PT J AU Hoffman, RN Leidner, SM Henderson, JM Atlas, R Ardizzone, JV Bloom, SC AF Hoffman, RN Leidner, SM Henderson, JM Atlas, R Ardizzone, JV Bloom, SC TI A two-dimensional variational analysis method for NSCAT ambiguity removal: Methodology, sensitivity, and tuning SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID SCATTEROMETER DATA; DIRECT-MINIMIZATION; SPACEBORNE SCATTEROMETER; OBJECTIVE ANALYSIS; DATA ASSIMILATION; MODEL FUNCTION; WIND VELOCITY; OCEAN; PARAMETERS; FORECAST AB In this study, a two-dimensional variational analysis method (2DVAR) is applied to select a wind solution from NASA Scatterometer (NSCAT) ambiguous winds. A 2DVAR method determines a "best'' gridded surface wind analysis by minimizing a cost function. The cost function measures the misfit to the observations, the background, and the filtering and dynamical constraints. The ambiguity closest in direction to the minimizing analysis is selected. The 2DVAR method, sensitivity, and numerical behavior are described. 2DVAR is used with both NSCAT ambiguities and NSCAT backscatter values. Results are roughly comparable. When the background field is poor, 2DVAR ambiguity removal often selects low probability ambiguities. To avoid this behavior, an initial 2DVAR analysis, using only the two most likely ambiguities, provides the first guess for an analysis using all the ambiguities or the backscatter data. 2DVAR and median filter-selected ambiguities usually agree. Both methods require horizontal consistency, so disagreements occur in clumps, or as linear features. In these cases, 2DVAR ambiguities are often more meteorologically reasonable and more consistent with satellite imagery. C1 Atmospher & Environm Res Inc, Lexington, MA 02421 USA. NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. Sci Applicat Int Corp, Beltsville, MD USA. RP Atmospher & Environm Res Inc, 131 Hartwell Ave, Lexington, MA 02421 USA. EM rhoffman@aer.com RI Atlas, Robert/A-5963-2011 OI Atlas, Robert/0000-0002-0706-3560 NR 62 TC 19 Z9 19 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 EI 1520-0426 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD MAY PY 2003 VL 20 IS 5 BP 585 EP 605 DI 10.1175/1520-0426(2003)20<585:ATDVAM>2.0.CO;2 PG 21 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 671EJ UT WOS:000182452100001 ER PT J AU Bolen, SM Chandrasekar, V AF Bolen, SM Chandrasekar, V TI Methodology for aligning and comparing spaceborne radar and ground-based radar observations SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article AB Direct intercomparisons between space- and ground-based radar measurements can be a challenging task. Differences in viewing aspects between space and earth observations, propagation paths, frequencies, resolution volume size, and time synchronization mismatch between space- and ground-based observations can contribute to direct point-by-point intercomparison errors. This problem is further complicated by geometric distortions induced upon the space- based observations caused by the movements and attitude perturbations of the spacecraft itself. A method to align measurements between these two systems is presented. The method makes use of variable resolution volume matching between the two systems and presents a technique to minimize the effects of potential geometric distortion in space radar observations relative to ground measurements. Applications of the method are shown that make a comparison between the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) reflectivity measurements and ground radar. C1 Colorado State Univ, Ft Collins, CO 80523 USA. RP Bolen, SM (reprint author), NASA, JSC, MC EV41,2101 NASA Rd 1, Houston, TX 77058 USA. NR 8 TC 27 Z9 28 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 2003 VL 20 IS 5 BP 647 EP 659 DI 10.1175/1520-0426(2003)20<647:MFAACS>2.0.CO;2 PG 13 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 671EJ UT WOS:000182452100005 ER PT J AU Knobelspiesse, KD Pietras, C Fargion, GS AF Knobelspiesse, KD Pietras, C Fargion, GS TI Sun-pointing-error correction for sea deployment of the MICROTOPS II handheld sun photometer SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID AEROSOL AB Handheld sun photometers, such as the MICROTOPS II (manufactured by Solar Light, Inc.), provide a simple and inexpensive way to measure in situ aerosol optical thickness (AOT), ozone content, and water vapor. Handheld sun photometers require that the user manually point the instrument at the sun. Unstable platforms, such as a ship at sea, can make this difficult. A poorly pointed instrument mistakenly records less than the full direct solar radiance, so the computed AOT is much higher than reality. The NASA Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project has been collecting maritime AOT data since 1997. As the dataset grew, a bias of the MICROTOPS II data with respect to other instrument data was noticed. This bias was attributed to the MICROTOPS II measurement protocol, which is intended for land-based measurements and does not remove pointing errors when used at sea. Based upon suggestions in previous literature, two steps were taken to reduce pointing errors. First, the measurement protocol was changed to keep the maximum (rather than average) voltage of a sequence of measurements. Once on shore, a second screening algorithm was utilized to iteratively reject outliers that represent sun-pointing errors. Several versions of this method were tested on a recent California Cooperative Oceanic Fisheries Investigations (CalCOFI) cruise, and were compared to concurrent measurements using the manufacturer-supplied protocol. Finally, a separate postprocessing algorithm was created for data previously gathered with the manufacturer-supplied protocol, based on statistics calculated by the instrument at the time of capture. C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, SIMBIOS Project, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Sci Applicat Int Corp, SIMBIOS Project, Greenbelt, MD 20771 USA. RP Knobelspiesse, KD (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, SIMBIOS Project, Code 970-2, Greenbelt, MD 20771 USA. RI Knobelspiesse, Kirk/S-5902-2016 OI Knobelspiesse, Kirk/0000-0001-5986-1751 NR 10 TC 18 Z9 19 U1 4 U2 5 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 2003 VL 20 IS 5 BP 767 EP 771 DI 10.1175/1520-0426(2003)20<767:SPECFS>2.0.CO;2 PG 5 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 671EJ UT WOS:000182452100016 ER PT J AU Mayr, HG Mengel, JG Drob, DP Porter, HS Chan, KL AF Mayr, HG Mengel, JG Drob, DP Porter, HS Chan, KL TI Modeling studies with QBO: I. Quasi-decadal oscillation SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article DE decadel oscillation; quasi biennial oscillation; middle atmosphere dynamics; gravity waves; atmospheric model ID DOPPLER-SPREAD PARAMETERIZATION; GENERAL-CIRCULATION MODEL; WAVE MOMENTUM DEPOSITION; BIENNIAL OSCILLATION; GRAVITY-WAVE; MIDDLE ATMOSPHERE; SEMIANNUAL OSCILLATION; EQUATORIAL OSCILLATIONS; INTERANNUAL VARIABILITY; ZONAL WIND AB Quasi-decadal oscillations (QDO) have been observed in the stratosphere and have been linked to the quasi-biennial oscillation (QBO) in the zonal circulation and to the 11-year solar activity cycle. With the use of a 2D version of our numerical spectral model that incorporates Hines' Doppler spread parameterization for gravity waves (GW), we demonstrate that beat periods between 9 and 11 years can be generated by the QBO as it interacts through GW filtering with the annual oscillation (AO) or semi-annual oscillation (SAO). Results are discussed from model runs covering up to 50 years, and our analyses lead to the following conclusions. A QDO is generated in the zonal circulation of the upper mesosphere. The largest signature of the QDO, however, appears in the form of amplitude modulations of the QBO, AO and SAO, and these extend into the lower stratosphere. The downward control that characterizes the QBO apparently comes into play, and the longer time constants for diffusion and radiative loss at lower altitudes facilitate the QDO response. Although excited by the QBO, which is confined to low latitudes, the QDO is shown to extend to high latitudes. The effect is particularly large for a QBO with period around 33 months (near the upper limit of observations), which interacts with the SAO to produce a hemispherically symmetric QDO. (The same dynamical condition also holds for a 28-month QBO.) Our analysis indicates that the QDO is transferred to high latitudes by the meridional circulation, which prominently exhibits this periodicity particularly in the amplitude modulation of the AO. (C) 2003 Elsevier Ltd. All rights reserved. C1 Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. USN, Res Lab, Washington, DC 20375 USA. Furman Univ, Greenville, SC 29613 USA. Univ Sci & Technol, Hong Kong, Hong Kong, Peoples R China. RP Mayr, HG (reprint author), Goddard Space Flight Ctr, MC 910-4, Greenbelt, MD 20771 USA. RI Drob, Douglas/G-4061-2014; OI Drob, Douglas/0000-0002-2045-7740; Chan, Kwing/0000-0002-6428-1812 NR 47 TC 12 Z9 12 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD MAY PY 2003 VL 65 IS 8 BP 887 EP 899 DI 10.1016/S1364-6826(03)00110-X PG 13 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 704QV UT WOS:000184352100001 ER PT J AU Mayr, HG Mengel, JG Drob, DP Chan, KL Porter, HS AF Mayr, HG Mengel, JG Drob, DP Chan, KL Porter, HS TI Modeling studies with QBO: II. Solar cycle effect SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article DE solar cycle effect; quasi biennial oscillation; middle atmosphere dynamics; gravity waves; atmospheric model ID QUASI-BIENNIAL OSCILLATION; DOPPLER-SPREAD PARAMETERIZATION; GENERAL-CIRCULATION MODEL; WAVE MOMENTUM DEPOSITION; MIDDLE ATMOSPHERE; GRAVITY-WAVE; SEMIANNUAL OSCILLATION; EQUATORIAL OSCILLATIONS; INTERANNUAL VARIABILITY; ZONAL WIND AB Solar cycle activity effects (SCAE) in the lower and middle atmosphere, reported in several studies, are difficult to explain on the basis of the small changes in solar radiation that accompany the 11-year cycle. It is therefore natural to speculate that dynamical processes may come into play to produce a leverage. Such a leverage may be provided by the quasi-biennial oscillation (QBO) in the zonal circulation of the stratosphere, which has been linked to solar activity variations (e.g., Labitzke (J. Meteorol. Soc. Jpn. 60 (1982) 124; Geophys. Res. Lett. 14 (1987) 135); Labitzke and Van Loon (J. Atm. Terr. Phys. 50 (1988) 197; J. Atm. Terr. Phys. 54 (1992) 1453)). Driven primarily by wave mean flow interaction, the QBO period and its amplitude are variable but are also strongly influenced by the seasonal cycle in the solar radiation. This influence extends to low altitudes and is referred to as "downward control". Small changes in the solar radiative forcing may produce small changes in the period and phase of the QBO, but these in turn may produce measurable differences in the wind field. Thus, the QBO may be an amplifier of solar activity variations and a natural conduit of these variations to lower altitudes. To test this hypothesis, we conducted experiments with a 2D version of our numerical spectral model that incorporates Hines' Doppler spread parameterization for small-scale gravity waves (GW). Solar cycle radiance variations (SCRV) are accounted for by changing the radiative heating rate on a logarithmic scale from 0.1% at the surface to 1% at 50 km to 10% at 100 km. With and without SCRV, but with the same GW flux, we then conduct numerical experiments to evaluate the magnitude of the SCAE in the zonal circulation. The numerical results show that, under certain conditions, the SCAE is significant and can extend to lower altitudes where the SCRV is small. For a modeled QBO period of 30 months, we find that the seasonal cycle in the solar forcing acts as a strong pacemaker to lock up the phase and period of the QBO. The SCAE then shows up primarily as a distinct but relatively weak amplitude modulation. But with a different QBO period between 30 and 34 (or < 30, presumably) months, the seasonal phase lock is weak. Solar flux variations in the seasonal cycle then cause variations in the QBO period and phase. These amplify the SCAE to produce relatively large variations in the wind field. The SCAE in this case extends to mid-latitudes. (C) 2003 Elsevier Ltd. All rights reserved. C1 Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. USN, Res Lab, Washington, DC 20375 USA. Univ Sci & Tech Lille Flandres Artois, Hong Kong, Hong Kong, Peoples R China. Furman Univ, Greenville, SC 29613 USA. RP Mayr, HG (reprint author), Goddard Space Flight Ctr, MC 910-4, Greenbelt, MD 20771 USA. RI Drob, Douglas/G-4061-2014; OI Drob, Douglas/0000-0002-2045-7740; Chan, Kwing/0000-0002-6428-1812 NR 49 TC 11 Z9 11 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD MAY PY 2003 VL 65 IS 8 BP 901 EP 916 DI 10.1016/S1364-6826(03)00111-1 PG 16 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 704QV UT WOS:000184352100002 ER PT J AU Biennier, L Salama, F Allamandola, LJ Scherer, JJ AF Biennier, L Salama, F Allamandola, LJ Scherer, JJ TI Pulsed discharge nozzle cavity ringdown spectroscopy of cold polycyclic aromatic hydrocarbon ions SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DIFFUSE INTERSTELLAR BANDS; ELECTRONIC ABSORPTION-SPECTROSCOPY; ASTROPHYSICAL IMPLICATIONS; PENNING IONIZATION; NAPHTHALENE CATION; GAS-PHASE; CARRIERS; RADICALS; CLUSTERS; SPECTRA AB The gas-phase electronic absorption spectra of the naphthalene (C10H8+) and acenaphthene (C12H10+) cations have been measured in the visible range in a free jet planar expansion in an attempt to collect data in an astrophysically relevant environment. The direct absorption spectra of two out of four bands measured of the gas-phase cold naphthalene cation along with the gas-phase vibronic absorption spectrum of the cold acenaphthene cation are reported for the first time. Direct absorption spectra of their van der Waals complexes with argon are also reported for the first time. The study has been carried out using the ultrasensitive and versatile technique of cavity ringdown spectroscopy (CRDS) coupled to a pulsed discharge slit nozzle (PDN). The new PDN-CRDS set up is described and its characteristics are evaluated. The direct-absorption spectra of the polycyclic aromatic hydrocarbon (PAH) ions are discussed and compared to the gas-phase and solid-phase data available in the literature. The analysis of the results show that cold, free flying PAH ions are generated in the argon discharge primarily through soft Penning ionization. This enables the intrinsic band profiles to be measured, a key requirement for astrophysical applications. (C) 2003 American Institute of Physics. C1 NASA, Ames Res Ctr, Space Sci Div, Moffett Field, CA 94035 USA. Los Gatos Res, Mountain View, CA 94041 USA. RP Biennier, L (reprint author), NASA, Ames Res Ctr, Space Sci Div, MS 245-6, Moffett Field, CA 94035 USA. EM lbiennier@mail.arc.nasa.gov RI Salama, Farid/A-8787-2009; Biennier, Ludovic/O-1618-2014 OI Salama, Farid/0000-0002-6064-4401; NR 40 TC 93 Z9 93 U1 2 U2 19 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 2003 VL 118 IS 17 BP 7863 EP 7872 DI 10.1063/1.1564044 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 668DY UT WOS:000182276100017 ER PT J AU Swiney, KM Shirley, TC Taggart, SJ O'Clair, CE AF Swiney, KM Shirley, TC Taggart, SJ O'Clair, CE TI Dungeness crab, Cancer magister, do not extrude eggs annually in southeastern Alaska: An in situ study SO JOURNAL OF CRUSTACEAN BIOLOGY LA English DT Article ID PACIFIC EDIBLE CRAB; SEASONAL MOVEMENTS; BEHAVIOR; DANA; ESTUARY; GROWTH; MALES AB The reproductive biology of female Dungeness crabs was studied with crab-pot and dive-transect sampling in five bays within or near Glacier Bay National Park and Preserve, southeastern Alaska, in April and September yearly from 1992 to 1998. A large percentage of nonovigerous, mature females was found in April, a time when females were expected to be brooding eggs that hatch in May and June. Our study examined differences between ovigerous and nonovigerous females collected in April and September samples to corroborate our previous laboratory study in which we found nonannual egg extrusion among Dungeness crabs. Seasonal differences in the catches of ovigerous and nonovigerous females, crab sizes, shell condition, and appendage injury were examined. Additionally, all crabs collected from two bays were tagged beginning in the fall of 1995; tagging was conducted twice annually. Our pot and dive data indicate that females, particularly larger ones, do not extrude eggs annually. Larger females have lower molting probabilities, which limits mating potential and increases reliance on stored sperm. The tagging study confirmed that at least some females do not extrude eggs in one year and then extrude eggs at a later time without molting, thus skipping at least one reproductive season. A reproductive cycle of Dungeness crabs in Alaska is introduced which includes earlier egg extrusion by larger females and nonannual egg extrusion. C1 Univ Alaska, Sch Fisheries & Ocean Sci, Juneau Ctr Fisheries & Ocean Sci, Juneau, AK 99801 USA. Glacier Bay Field Stn, Alaska Sci Ctr, US Geol Survey, Douglas, AK 99824 USA. Auke Bay Lab, Natl Marine Fisheries Serv, Juneau, AK 99801 USA. RP Swiney, KM (reprint author), Kodiak Fisheries Res Ctr, Natl Marine Fisheries Serv, 301 Res Court, Kodiak, AK 99615 USA. EM Katherine.Swiney@noaa.gov; Tom.Shirley@uaf.edu; Jim_Taggart@usgs.gov; cnroclair@rockisland.com NR 29 TC 9 Z9 9 U1 0 U2 5 PU CRUSTACEAN SOC PI SAN ANTONIO PA 840 EAST MULBERRY, SAN ANTONIO, TX 78212 USA SN 0278-0372 J9 J CRUSTACEAN BIOL JI J. Crustac. Biol. PD MAY PY 2003 VL 23 IS 2 BP 280 EP 288 DI 10.1651/0278-0372(2003)023[0280:DCCMDN]2.0.CO;2 PG 9 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 679PQ UT WOS:000182931500005 ER PT J AU Olson, KR Dewar, H Graham, JB Brill, RW AF Olson, KR Dewar, H Graham, JB Brill, RW TI Vascular anatomy of the gills in a high energy demand teleost, the skipjack tuna (Katsuwonus pelamis) SO JOURNAL OF EXPERIMENTAL ZOOLOGY PART A-COMPARATIVE EXPERIMENTAL BIOLOGY LA English DT Article ID ACCESSORY RESPIRATORY ORGANS; SECONDARY CIRCULATION; FISH GILL; MORPHOLOGY; MICROCIRCULATION; ORGANIZATION; CATFISH; FILAMENT; PRESSURE AB Tunas (family: Scombridae, Tribe: Thunnini) exhibit anatomical, physiological, and biochemical adaptations that dramatically increase the ability of their cardiorespiratory systems to transfer oxygen from the water to the tissues. In the present study the vascular anatomy of the skipjack tuna, Katsuwonus pelamis, gill was examined by light and scanning electron microscopic analysis of methyl methacrylate vascular corrosion replicas prepared under physiological pressure. The gill filament contains three distinct blood pathways, respiratory, interlamellar, and nutrient. The respiratory, or arterio-arterial (AA) pathway, is the site of gas exchange and consists of the afferent and efferent filamental arteries (AFA and EFA) and arterioles (ALA and ELA) and the lamellae. Each ALA in the basal filament supplies ten or more lamellae and they anastomose with their neighbor to form a continuous vascular arcade. Four modifications in the lamellar circulation appear to enhance gas exchange efficiency. 1) The ALA deliver blood directly to the outer margin of the lamellae where unstirred boundary layer effects are predicted to be minimal and water PO2 highest. 2) Pillar cells are closely aligned along the outer boundary of the inlet side and the inner boundary of the outlet side of the lamellae to form multiple distributing and receiving blood channels. 3) Elsewhere in the lamella, pillar cells are aligned to form diagonal channels that direct blood from the outer to the inner lamellar margins, thereby reducing vascular resistance. 4) The lamellar sinusoid is especially widened near the efferent end to augment oxygen saturation of blood flowing through the inner margin. These adaptations, plus the presence of a bow-shaped interlamellar septum, and a thinned filament core appear to decrease gill vascular resistance and maximize gas-exchange efficiency. The interlamellar (IL) and nutrient systems originate from post-lamellar vessels and are arterio-venous (AV) pathways. IL vessels form an extensive ladder-like lattice on both sides of the filamental. cartilage and are supplied in part by narrow-bore vessels from the medial wall of the EFA. Their function is unknown. Nutrient vessels are formed from the confluence of a myriad of tortuous, narrow-bore vessels arising from the basal region of the EFA and from efferent branchial arteries. They re-enter the filament and eventually drain into the IL system or filamental veins. As these AV pathways are retained despite considerable reduction in filamental tissue, it is evident that they are integral components of other non-respiratory homeostatic activities of the gill. (C) 2003 Wiley-Liss, Inc. C1 Univ Notre Dame, Indiana Univ, Sch Med, S Bend Ctr Med Educ, Notre Dame, IN 46556 USA. Pfleger Inst Environm Res, Oceanside, CA 92054 USA. Univ Calif San Diego, Scripps Inst Oceanog, Ctr Marine Biotechnol, La Jolla, CA 92093 USA. Univ Calif San Diego, Scripps Inst Oceanog, Biomed & Marine Biol Res Div, La Jolla, CA 92093 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu, HI 96822 USA. RP Olson, KR (reprint author), Univ Notre Dame, Indiana Univ, Sch Med, S Bend Ctr Med Educ, B-19 Haggar Hall, Notre Dame, IN 46556 USA. NR 31 TC 10 Z9 10 U1 1 U2 15 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0022-104X J9 J EXP ZOOL PART A JI J. Exp. Zool. Part A PD MAY 1 PY 2003 VL 297A IS 1 BP 17 EP 31 DI 10.1002/jez.a.10262 PG 15 WC Zoology SC Zoology GA 674GK UT WOS:000182628900002 PM 12911110 ER PT J AU Fischer, B Schumann, J AF Fischer, B Schumann, J TI AutoBayes: a system for generating data analysis programs from statistical models SO JOURNAL OF FUNCTIONAL PROGRAMMING LA English DT Article; Proceedings Paper CT International Workshop on Semantics, Applications, and Implementation of Program Generation CY SEP 20, 2000 CL MONTREAL, CANADA SP ACM, SIGPLAN AB Data analysis is an important scientific task which is required whenever information needs to be extracted from raw data. Statistical approaches to data analysis, which use methods from probability theory and numerical analysis, are well-founded but difficult to implement: the development of a statistical data analysis program for any given application is time-consuming and requires substantial knowledge and experience in several areas. In this paper, we describe AUTOBAYEs, a program synthesis system for the generation of data analysis programs from statistical models. A statistical model specifies the properties for each problem variable (i.e. observation or parameter) and its dependencies in the form of a probability distribution. It is a fully declarative problem description, similar in spirit to a set of differential equations. From such a model, AUTOBAYES generates optimized and fully commented C/C++ code which can be linked dynamically into the Matlab and Octave environments. Code is produced by a schema-guided deductive synthesis process. A schema consists of a code template and applicability constraints which are checked against the model during synthesis using theorem proving technology. AUTOBAYEs augments schema-guided synthesis by symbolic-algebraic computation and can thus derive closed form solutions for many problems. It is well-suited for tasks like estimating best-fitting model parameters for the given data. Here, we describe AUTOBAYES'S system architecture, in particular the schema-guided synthesis kernel. Its capabilities are illustrated by a number of advanced textbook examples and benchmarks. C1 NASA, RIACS, Moffett Field, CA 94035 USA. RP NASA, RIACS, Moffett Field, CA 94035 USA. EM fisch@email.arc.nasa.gov; schumann@email.arc.nasa.gov NR 35 TC 40 Z9 40 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0956-7968 EI 1469-7653 J9 J FUNCT PROGRAM JI J. Funct. Program PD MAY PY 2003 VL 13 BP 483 EP 508 DI 10.1017/S0956796802004562 PN 3 PG 26 WC Computer Science, Software Engineering SC Computer Science GA 689BA UT WOS:000183470700003 ER PT J AU Grasby, SE Allen, CC Longazo, TG Lisle, JT Griffin, DW Beauchamp, B AF Grasby, SE Allen, CC Longazo, TG Lisle, JT Griffin, DW Beauchamp, B TI Biogeochemical sulphur cycle in an extreme environment - life beneath a high arctic glacier, Nunavut, Canada SO JOURNAL OF GEOCHEMICAL EXPLORATION LA English DT Article; Proceedings Paper CT GEOFLUIDS IV Meeting CY MAY 12-16, 2003 CL UTRECHT, NETHERLANDS DE sulfur springs; subglacial; bacteria; arctic ID ROCK AB Unique springs discharge from the surface of a high arctic glacier, releasing H2S, and depositing native sulphur, gypsum, and calcite. A rare CaCO3 polymorph, vaterite, is also observed. Physical and chemical conditions of the spring water and surrounding environment, as well as mineralogical and isotopic signatures, argue for biologically mediated redox reactions controlling sulfur. Cell counts and DNA analyses, confirm bacteria are present in the spring system. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Nat Resources Canada, Geol Survey Canada, Calgary, AB T2L 2A7, Canada. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Hernandez Engn, Houston, TX 77058 USA. US Geol Survey, Ctr Coastal & Watershed Res, St Petersburg, FL 33701 USA. RP Grasby, SE (reprint author), Nat Resources Canada, Geol Survey Canada, 3303 33rd St NW, Calgary, AB T2L 2A7, Canada. OI Grasby, Stephen/0000-0002-3910-4443 NR 12 TC 4 Z9 4 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-6742 J9 J GEOCHEM EXPLOR JI J. Geochem. Explor. PD MAY PY 2003 VL 78-9 SI SI BP 71 EP 74 DI 10.1016/S0375-6742(03)00026-8 PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 673LQ UT WOS:000182582800014 ER PT J AU Paielli, RA AF Paielli, RA TI Modeling maneuver dynamics in air traffic conflict resolution SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID FREE-FLIGHT AB Much of the previous literature on conflict resolution is based on instantaneous maneuver models, in which speed and/or heading change dynamics are unmodeled. The effects of the actual maneuver dynamics on the resulting minimum separation are analyzed, and a simple numerical algorithm is presented to compensate for those effects. The focus is on level flight in the horizontal plane. Speed changes are modeled as periods of constant along-track acceleration or deceleration, and heading changes are modeled as steady turns of constant rate and radius. These simple kinematic (constrained point-mass) models improve on the resolution accuracy that results from modeling speed and heading changes as instantaneous, but they yield much simpler solutions than general point-mass dynamic models. The accuracy improvement is minor for most heading-change maneuvers, but it is substantial for most speed-change maneuvers. An important operational benefit of the algorithm is that it detects immediately if a conflict is too close to be resolved by a particular maneuver. A method is also outlined for determining the optimal combination of speed and heading change to resolve conflicts. With minor adaptation, the algorithms can also make use of an existing conflict probability estimation algorithm to determine maneuvers for strategic conflict probability reduction. C1 NASA, Ames Res Ctr, Aviat Syst Div, Moffett Field, CA 94035 USA. RP Paielli, RA (reprint author), NASA, Ames Res Ctr, Aviat Syst Div, AFC 210-10, Moffett Field, CA 94035 USA. NR 8 TC 19 Z9 19 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAY-JUN PY 2003 VL 26 IS 3 BP 407 EP 415 DI 10.2514/2.5078 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 677UB UT WOS:000182825100003 ER PT J AU Das, T Mukherjee, R Cameron, J AF Das, T Mukherjee, R Cameron, J TI Optimal trajectory planning for hot-air balloons in linear wind fields SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB The altitude of hot-air balloons is controlled by heating the air trapped inside the balloon and allowing the air to cool naturally. Apart from controlling the altitude, it is desirable-to utilize the wind field to position the balloon at a target location while minimizing fuel consumption. This can be posed as an optimal control problem with free end states, where the heat input to the system is the control variable. The problem is intractable because of the switching nature of the heat input and highly nonlinear state equations derived from the thermodynamic model of the balloon. In this paper we address the optimal control problem within a space of a few kilometers where we assume the wind fields to be known and linear. We simplify the dynamic model of the balloon and obtain optimal trajectories to the target location by solving a two-point boundary-value problem. By refining the simplified dynamic model, the accuracy of the optimal trajectories are improved to match well with trajectories obtained using the nonlinear model. Our approach based on simplification of the balloon dynamic model enables us to solve the intractable nonlinear optimal control problem and provides insight into the optimal trajectories, such as number of switchings of input and loss of accuracy for specific wind profiles. Except for these specific wind profiles, our approach yields accurate trajectories for the balloon and provides a solution to an important problem that has not been adequately addressed in the literature. C1 Michigan State Univ, Dept Mech Engn, E Lansing, MI 48824 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Das, T (reprint author), Michigan State Univ, Dept Mech Engn, 2555 Engn Bldg, E Lansing, MI 48824 USA. RI Mukherjee, Ranjan/A-7518-2009 NR 12 TC 9 Z9 12 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAY-JUN PY 2003 VL 26 IS 3 BP 416 EP 424 DI 10.2514/2.5079 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 677UB UT WOS:000182825100004 ER PT J AU Singh, SN Brenner, M AF Singh, SN Brenner, M TI Modular adaptive control of a nonlinear aeroelastic system SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID OUTPUT-FEEDBACK CONTROL; WIND-TUNNEL MODEL; FLUTTER SUPPRESSION; ACTIVE CONTROL; STABILIZATION; SECTION AB The paper treats the question of adaptive control of prototypical aeroelastic wing sections with structural nonlinearity. The chosen dynamic model describes the nonlinear plunge and pitch motion of a wing. The model has both the plunge and pitch structural nonlinearities, and a single control surface is used for the purpose of control. It is assumed that only the sign of the coefficient of the control input and the lower bound on its absolute value are known, and the remaining parameters of the model are completely unknown. Modular adaptive control systems based on estimation-based design are derived for the control of the pitch angle and the plunge displacement. Unlike the direct adaptive controllers available in the literature, an input-to-state stabilizing control law is used herein. This control law accomplishes input-to-state stability with respect to parameter estimation error treated as a disturbance input. The control system includes a passive identifier (an observer and an adaptation law) for the parameter estimation. In the closed-loop system asymptotic stabilization of the plunge and pitch motion is accomplished. Simulation results are presented to show that the modular adaptive control systems accomplish flutter suppression in spite of the large uncertainties in the system. Simulation results also show that the closed-loop system without parameter adaptation fails to suppress flutter, but the input-to-state-stabilizing controller is effective in keeping the pitch and plunge responses bounded. C1 NASA, Dryden Flight Res Ctr, Aerostruct Branch, Edwards AFB, CA 93523 USA. Univ Nevada, Dept Elect & Comp Engn, Las Vegas, NV 89154 USA. RP Singh, SN (reprint author), Univ Nevada, Dept Elect & Comp Engn, Las Vegas, NV 89154 USA. NR 28 TC 12 Z9 12 U1 0 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAY-JUN PY 2003 VL 26 IS 3 BP 443 EP 451 DI 10.2514/2.5082 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 677UB UT WOS:000182825100007 ER PT J AU Yeh, NC Chen, CT Vasquez, RP Jung, CU Lee, SI Yoshida, K Tajima, S AF Yeh, NC Chen, CT Vasquez, RP Jung, CU Lee, SI Yoshida, K Tajima, S TI Scanning Tunneling spectroscopic studies of the pairing state of cuprate superconductors SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on Physics and Chemistry of Molecular and Oxide Superconductors (MOS2002) CY AUG 13-18, 2002 CL HSINCHU, TAIWAN ID HIGH-TEMPERATURE SUPERCONDUCTORS; INFINITE-LAYER CUPRATE; D-WAVE SUPERCONDUCTORS; T-C SUPERCONDUCTORS; UNDERDOPED BI2SR2CACU2O8+DELTA; QUANTUM CRITICALITY; SINGLE-CRYSTALS; SYMMETRY; IMPURITY; SPECTRA AB Quasiparticle tunneling spectra of both hole-doped (p-type) and electron-doped (n-type) cuprates are studied using a low-temperature scanning tunneling microscope. The results reveal that neither the pairing symmetry nor the pseudogap phenomenon is universal among all cuprates, and that the response of n-type cuprates to quantum impurities is drastically different from that of the p-type cuprates. The only ubiquitous features among all cuprates appear to be the strong electronic correlation and the nearest-neighbor antiferromagnetic Cu2+-Cu2+ coupling in the CuO2 planes. C1 CALTECH, Dept Phys, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Pohang Univ Sci & Technol, Dept Phys, Pohang 790784, South Korea. Int Supercond Technol Ctr, Supercond Res Lab, Koto Ku, Tokyo 135, Japan. RP CALTECH, Dept Phys, Pasadena, CA 91125 USA. NR 48 TC 8 Z9 8 U1 0 U2 0 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 EI 1573-7357 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD MAY PY 2003 VL 131 IS 3-4 BP 435 EP 444 DI 10.1023/A:1022934832360 PG 10 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 659GB UT WOS:000181768000042 ER PT J AU Hudson, ST Zoladz, TF Dorney, DJ AF Hudson, ST Zoladz, TF Dorney, DJ TI Rocket engine turbine blade surface pressure distributions: Experiment and computations SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB Understanding the unsteady aspects of turbine rotor flowfields is critical to successful future turbine designs. A technology program was conducted at NASA Marshall Space Flight Center to increase the understanding of unsteady environments for rocket engine turbines. The experimental program involved instrumenting turbine rotor blades with miniature surface-mounted high-frequency response pressure transducers. The turbine model was then tested to measure the unsteady pressures on the rotor blades. The data obtained from the experimental program are unique in two respects. First, much more unsteady data were obtained (several minutes per set point) than have been possible in the past. Also, an extensive steady performance database existed for the turbine model. This allowed an evaluation of the effect of the onblade instrumentation on the turbine's performance. A three-dimensional unsteady Navier-Stokes analysis was also used to predict blindly the unsteady flowfield in the turbine at the design operating conditions and at +15 deg relative incidence to the first-stage rotor. The predicted time-averaged and unsteady pressure distributions show good agreement with the experimental data. This unique data set, the lessons learned for acquiring this type of data, and the improvements made to the data analysis and prediction tools are contributing significantly to current space launch initiative turbine airflow test and blade surface pressure prediction efforts. C1 Mississippi State Univ, Dept Mech Engn, Mississippi State, MS 39762 USA. NASA, George C Marshall Space Flight Ctr, Space Transportat Directorate, Huntsville, AL 35812 USA. RP Hudson, ST (reprint author), Mississippi State Univ, Dept Mech Engn, Mississippi State, MS 39762 USA. NR 17 TC 0 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 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2003 VL 19 IS 3 BP 364 EP 373 DI 10.2514/2.6140 PG 10 WC Engineering, Aerospace SC Engineering GA 681KZ UT WOS:000183036500005 ER PT J AU Domonkos, MT Patterson, MJ Gallimore, AD AF Domonkos, MT Patterson, MJ Gallimore, AD TI Low-current, xenon orificed hollow cathode performance for in-space applications SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB An experimental investigation of the operating characteristics of 3.2-mm-diam orificed hollow cathodes was conducted to examine low-current and low How-rate operation. Cathode power for self-sustaining keeper operation was minimized with an orifice aspect ratio of approximately one or through the use of an enclosed keeper. For spot-mode emission cathode flow-rate requirements were proportional to orifice diameter and the inverse of the orifice length. The minimum power consumption in diode mode was 10 W, and the minimum mass flow rate required for spot-mode emission was approximately 0.08 mg/s. Cathode temperature profiles were obtained using an imaging radiometer, and conduction was found to be the dominant heat-transfer mechanism from the cathode tube. Orifice plate temperatures were found to be weakly dependent upon the flow rate and strongly dependent upon the current. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Michigan, Plasmadynam & Elect Prop Lab, Ann Arbor, MI 48109 USA. RP Domonkos, MT (reprint author), NASA, Glenn Res Ctr, Mail Stop 301-3,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 21 TC 7 Z9 7 U1 1 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 2003 VL 19 IS 3 BP 438 EP 443 DI 10.2514/2.6127 PG 6 WC Engineering, Aerospace SC Engineering GA 681KZ UT WOS:000183036500013 ER PT J AU Sims, JD Coleman, HW AF Sims, JD Coleman, HW TI Hysteresis effects on thrust measurement and its uncertainty SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB The work detailed herein describes a combination of experiments and numerical analysis meant to explore potential causes of both errors and hysteresis in a thrust measurement system and how they affect data reduction and uncertainty estimation. An uncertainty estimate of average hybrid motor thrust is also demonstrated. There were two major conclusions of this effort. First, hysteresis evident in a hybrid rocket motor test stand was eliminated through proper motor and thrust measurement system alignment. Second, Monte Carlo simulations showed that not including an elemental uncertainty contribution for hysteresis in an otherwise rigorous uncertainty propagation is a valid engineering approximation, when the experimental result is the average of data containing small (percentagewise) fluctuations. C1 NASA, George C Marshall Space Flight Ctr, Space Transportat Directorate, Huntsville, AL 35812 USA. Univ Alabama, Dept Mech & Aerosp Engn, Prop Res Ctr, Huntsville, AL 35899 USA. RP Sims, JD (reprint author), NASA, George C Marshall Space Flight Ctr, Space Transportat Directorate, Huntsville, AL 35812 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2003 VL 19 IS 3 BP 506 EP 513 DI 10.2514/2.6135 PG 8 WC Engineering, Aerospace SC Engineering GA 681KZ UT WOS:000183036500020 ER PT J AU Shippony, Z Read, WG AF Shippony, Z Read, WG TI A correction to a highly accurate Voigt function algorithm (vol 78, pg 255, 2003) SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Correction C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Read, WG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 7 Z9 7 U1 0 U2 5 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 1 PY 2003 VL 78 IS 2 BP 255 EP 255 AR PII S0022-4073(02)00169-3 DI 10.1016/S0022-4073(02)00169-3 PG 1 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 655KN UT WOS:000181551200014 ER PT J AU Butler, JJ Brown, SW Saunders, RD Johnson, BC Biggar, SF Zalewski, EF Markham, BL Gracey, PN Young, JB Barnes, RA AF Butler, JJ Brown, SW Saunders, RD Johnson, BC Biggar, SF Zalewski, EF Markham, BL Gracey, PN Young, JB Barnes, RA TI Radiometric measurement comparison on the integrating sphere source used to calibrate the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE calibration; Earth Observing System (EOS); integrating sphere; Mderate Rsolution Imaging Spectroradiometer (MODIS); Landsat 7 Enhanced Thematic Mapper Plus (ETM plus ); remote sensing; spectral radiometry; transfer radiometers ID SPACEBORNE THERMAL EMISSION; REFLECTION RADIOMETER; INSTRUMENT; ASTER AB As part of a continuing effort to validate the radiometric scales assigned to integrating sphere sources used in the calibration of Earth Observing System (EOS) instruments, a radiometric measurement comparison was held in May 1998 at Raytheon/Santa Barbara Remote Sensing (SBRS). This comparison was conducted in support of the calibration of the Moderate Resolution Imaging Spectroradiometer ( MODIS) and the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) instruments. The radiometric scale assigned to the Spherical Integrating Source (SIS100) by SBRS was validated through a comparison with radiometric measurements made by a number of stable, well-characterized transfer radiometers from the National Institute of Standards and Technology (NIST), the National Aeronautics and Space Administration's Goddard Space Flight Center (NASA's GSFC), and the University of Arizona Optical Sciences Center (UA). The measured radiances from the radiometers differed by +/- 3 % in the visible to near infrared when compared to the SBRS calibration of the sphere, and the overall agreement was within the combined uncertainties of the individual measurements. In general, the transfer radiometers gave higher values than the SBRS calibration in the near infrared and lower values in the blue. The measurements of the radiometers differed by +/- 4 % from 800 nm to 1800 nm compared to the SBRS calibration of the sphere, and the overall agreement was within the combined uncertainties of the individual measurements for wavelengths less than 2200 nm. The results of the radiometric measurement comparison presented here supplement the results of previous measurement comparisons on the integrating sphere sources used to calibrate the Multi-angle Imaging SpectroRadiometer (MISR) at NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) at NEC Corporation, Yokohama, Japan. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Arizona, Remote Sensing Grp, Ctr Opt Sci, Tucson, AZ 85721 USA. Raytheon Santa Barbara Remote Sensing, Goleta, CA 93117 USA. Sci Applicat Int Corp, Beltsville, MD 20705 USA. RP Butler, JJ (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. EM James.J.Butler@nasa.gov; steven.brown@nist.gov; robert.saunders@nist.gov; cjohnson@nist.gov RI Markham, Brian/M-4842-2013; Butler, James/D-4188-2013 OI Markham, Brian/0000-0002-9612-8169; NR 24 TC 22 Z9 22 U1 0 U2 7 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD MAY-JUN PY 2003 VL 108 IS 3 BP 199 EP 228 DI 10.6028/jres.108.020 PG 30 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 699AU UT WOS:000184034400004 PM 27413606 ER PT J AU Gnoffo, PA AF Gnoffo, PA TI Computational aerothermodynamics in aeroassist applications SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA 15th Computational Fluid Dynamics Conference CY JUN 11-14, 2001 CL ANAHEIM, CALIFORNIA SP AIAA ID SCHEMES AB Aeroassisted planetary entry uses atmospheric drag to decelerate spacecraft from superorbital to orbital or suborbital velocities. Numerical simulation of flowfields surrounding these spacecraft during hypersonic atmospheric entry is required to define aerothermal loads. The severe compression in the shock layer in front of the vehicle and subsequent, rapid expansion into the wake are characterized by high-temperature, thermochemical nonequilibrium processes. Implicit algorithms required for efficient, stable computation of the governing equations involving disparate timescales of convection, diffusion, chemical reactions, and thermal relaxation are discussed. Robust point-implicit strategies are utilized in the initialization phase; less robust, but more efficient line-implicit strategies are applied in the endgame. Applications to ballutes (balloonlike decelerators) in the atmospheres of Venus, Mars, Titan, Saturn, and Neptune and a Mars Sample Return Orbiter are featured. Examples are discussed where time-accurate simulation is required to achieve a steady-state solution. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Gnoffo, PA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 25 TC 5 Z9 6 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 2003 VL 40 IS 3 BP 305 EP 312 DI 10.2514/2.3957 PG 8 WC Engineering, Aerospace SC Engineering GA 687FN UT WOS:000183365800001 ER PT J AU Johnson, WR Longuski, JM Lyons, DT AF Johnson, WR Longuski, JM Lyons, DT TI Pitch control during autonomous aerobraking for near-term Mars exploration SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AAS/AIAA Astrodynamics Specialists Conference CY JUL 30-AUG 02, 2001 CL QUEBEC CITY, CANADA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID GLOBAL SURVEYOR; DESIGN AB Conventional aerobraking requires propellant to dump the spacecraft's angular momentum and to maintain attitude control during the atmospheric flythrough. We consider how reaction wheels can be used to control the spacecraft's pitch during each atmospheric flythrough and to reduce angular momentum simultaneously. Control laws are developed for minimum onboard instrumentation (where the only state information are the angular rates of the spacecraft and the reaction wheels) to compensate for large variations in entry time and atmospheric density. Simulations indicate that pitch attitude and angular momentum can be controlled with reaction wheels alone, thus saving precious propellant while significantly increasing the timing margin for sequencing. C1 Purdue Univ, Sch Aeronaut & Astronaut, W Lafayette, IN 47907 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Johnson, WR (reprint author), Purdue Univ, Sch Aeronaut & Astronaut, W Lafayette, IN 47907 USA. NR 14 TC 4 Z9 5 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 2003 VL 40 IS 3 BP 371 EP 379 DI 10.2514/2.3972 PG 9 WC Engineering, Aerospace SC Engineering GA 687FN UT WOS:000183365800008 ER PT J AU Loncar, M Scherer, A Qiu, YM AF Loncar, M Scherer, A Qiu, YM TI Nanocavity lasers detect chemicals SO LASER FOCUS WORLD LA English DT Article ID 2-DIMENSIONAL PHOTONIC CRYSTAL; MODE; SLAB AB Photonic-crystal lasers have been developed that permit the introduction of analyte within the peak of the optical field of the lasing mode. These nanocavity lasers can be operated in different ambient organic solutions, performing spectroscopic tests on femtoliter volumes of analyte. C1 CALTECH, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Loncar, M (reprint author), CALTECH, 1200 E Calif Blvd, Pasadena, CA 91125 USA. EM etcher@caltech.edu NR 9 TC 0 Z9 0 U1 0 U2 0 PU PENNWELL PUBL CO PI NASHUA PA 98 SPIT BROOK RD, NASHUA, NH 03062-2801 USA SN 1043-8092 J9 LASER FOCUS WORLD JI Laser Focus World PD MAY PY 2003 VL 39 IS 5 BP 89 EP 91 PG 3 WC Optics SC Optics GA 685CX UT WOS:000183244200035 ER PT J AU DellaCorte, C AF DellaCorte, C TI Competition promotes consumer value SO LUBRICATION ENGINEERING LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Washington, DC 20546 USA. RP DellaCorte, C (reprint author), NASA, Glenn Res Ctr, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 2 U2 3 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD MAY PY 2003 VL 59 IS 5 BP 3 EP 3 PG 1 WC Engineering, Mechanical SC Engineering GA 688AN UT WOS:000183410100001 ER PT J AU Martin, RE Gyekenyesi, AL Shepard, SM AF Martin, RE Gyekenyesi, AL Shepard, SM TI Interpreting the results of pulsed thermography data SO MATERIALS EVALUATION LA English DT Article DE pulsed thermography; ceramic composites; nondestructive testing AB Pulsed thermography is a powerful method for the nondestructive testing (NDT) of composite materials since it provides a large field means for detecting subsurface material discontinuities and material variations. The main difficulty in the use of this technique, however, is the processing and interpretation of the acquired thermal image data. This paper examines three methods for processing pulsed thermography results concerning a composite plate with material inserts that simulate delamination type discontinuities. Using the same temporal data set, a specimen is analyzed utilizing peak contrast, peak slope and a newly developed thermal image reconstruction technique. Comparisons are made on a composite panel with differing discontinuity sizes and depths. In addition, results are compared to images gathered using through transmission ultrasonics and microfocus radiography. With subjective manipulation, pulsed thermography was able to show the discontinuities more clearly than either the ultrasonic or radiographic techniques. A discussion of this subjectivity and future directions for automation are provided in an effort to better understand the potential of the method. C1 Cleveland State Univ, NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. OAI, NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Thermal Wave Imaging, Ferndale, MI 48220 USA. RP Martin, RE (reprint author), Cleveland State Univ, NASA, Glenn Res Ctr, 21000 Brookpk Rd,MS 6-1, Cleveland, OH 44135 USA. NR 7 TC 30 Z9 30 U1 1 U2 8 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 USA SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD MAY PY 2003 VL 61 IS 5 BP 611 EP 616 PG 6 WC Materials Science, Characterization & Testing SC Materials Science GA 675DM UT WOS:000182677800008 ER PT J AU Bogard, DD Garrison, DH AF Bogard, DD Garrison, DH TI Ar-39-Ar-40 ages of eucrites and thermal history of asteroid 4 Vesta SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID HED PARENT BODY; PIPLIA-KALAN; SOLAR-SYSTEM; BASALTIC ACHONDRITES; NONCUMULATE EUCRITE; IBITIRA EUCRITE; LUNAR CATACLYSM; NOBLE-GASES; METEORITES; IMPACT AB Eucrite meteorites are igneous rocks that derived from a large asteroid, probably 4 Vesta. Past studies have shown that after most eucrites formed, they underwent metamorphism in temperatures up to greater than or equal to800degreesC. Much later, many were brecciated and heated by large impacts into the parent body surface. The less common basaltic, unbrecciated eucrites also formed near the surface but, presumably, escaped later brecciation, while the cumulate eucrites formed at depths where metamorphism may have persisted for a considerable period. To further understand the complex HED parent body thermal history, we determined new Ar-39-Ar-40 ages for 9 eucrites classified as basaltic but unbrecciated, 6 eucrites classified as cumulate, and several basaltic-brecciated eucrites. Precise Ar-Ar ages of 2 cumulate eucrites (Moama and EET 87520) and 4 unbrecciated eucrites give a tight cluster at 4.48 +/- 0.02 Gyr (not including any uncertainties in the flux monitor age). Ar-Ar ages of 6 additional unbrecciated eucrites are consistent with this age within their relatively larger age uncertainties. By contrast, available literature data on Pb-Pb isochron ages of 4 cumulate eucrites and 1 unbrecciated eucrite vary over 4.4-4.515 Gyr, and Sm-147-Nd-143 isochron ages of 4 cumulate and 3 unbrecciated eucrites vary over 4.41-4.55 Gyr. Similar Ar-Ar ages for cumulate and unbrecciated eucrites imply that cumulate eucrites do not have a younger formation age than basaltic eucrites, as was previously proposed. We suggest that these cumulate and unbrecciated eucrites resided at a depth where parent body temperatures were sufficiently high to cause the K-Ar and some other chronometers to remain as open diffusion systems. From the strong clustering of Ar-Ar ages at similar to4.48 Gyr, we propose that these meteorites were excavated from depth in a single large impact event similar to4.48 Gyr ago, which quickly cooled the samples and started the K-Ar chronometer. A large (similar to460 km) crater postulated to exist on Vesta may be the source of these eucrites and of many smaller asteroids thought to be spectrally or physically associated with Vesta. Some Pb-Pb and Sm-Nd ages of cumulate and unbrecciated eucrites are consistent with the Ar-Ar age of 4.48 Gyr, and the few older Pb-Pb and Sm-Nd ages may reflect an isotopic closure before the large cratering event. One cumulate eucrite gives an Ar-Ar age of 4.25 Gyr; 3 additional cumulate eucrites give Ar-Ar ages of 3.4-3.7 Gyr; and 2 unbrecciated eucrites give Ar-Ar ages of similar to3.55 Gyr. We attribute these younger ages to a later impact heating. Furthermore, the Ar-Ar impact-reset ages of several brecciated eucrites and eucritic clasts in howardites fall within the range of 3.5-4.1 Gyr. Among these, Piplia Kalan, the first eucrite to show evidence for extinct Al-26, was strongly impact heated similar to3.5 Gyr ago. When these data are combined with eucrite Ar-Ar ages in the literature, they confirm that several large impact heating events occurred on Vesta between similar to4.1-3.4 Gyr ago. The onset of major impact heating may have occurred at similar times for both Vesta and the moon, but impact heating appears to have persisted for a somewhat later time on Vesta. C1 NASA, Johnson Space Ctr, SR, Astromat Res, Houston, TX 77058 USA. Lockheed Martin Corp, Houston, TX 77058 USA. RP Bogard, DD (reprint author), NASA, Johnson Space Ctr, SR, Astromat Res, Houston, TX 77058 USA. NR 92 TC 67 Z9 67 U1 0 U2 12 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 2003 VL 38 IS 5 BP 669 EP 710 PG 42 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 721WW UT WOS:000185342300002 ER PT J AU Ghosh, A Weidenschilling, SJ McSween, HY AF Ghosh, A Weidenschilling, SJ McSween, HY TI Importance of the accretion process in asteroid thermal evolution: 6 Hebe as an example SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID EARLY SOLAR-SYSTEM; PARENT BODY; ORDINARY CHONDRITES; TERRESTRIAL PLANETS; GIANT PLANETS; METEORITES; AL-26; PLANETESIMALS; CONSTRAINTS; CHONDRULES AB Widespread evidence exists for heating that caused melting, thermal metamorphism, and aqueous alteration in meteorite parent bodies. Previous simulations of asteroid heat transfer have assumed that accretion was instantaneous. For the first time, we present a thermal model that assumes a realistic (incremental) accretion scenario and takes into account the heat budget produced by decay of Al-26 during the accretion process. By modeling 6 Hebe (assumed to be the H chondrite parent body), we show that, in contrast to results from instantaneous accretion models, an asteroid may reach its peak temperature during accretion, the time at which different depth zones within the asteroid attain peak metamorphic temperatures may increase from the center to the surface, and the volume of high-grade material in the interior may be significantly less than that of unmetamorphosed material surrounding the metamorphic core. We show that different times of initiation and duration of accretion produce a spectrum of evolutionary possibilities, and thereby, highlight the importance of the accretion process in shaping an asteroid's thermal history. Incremental accretion models provide a means of linking theoretical models of accretion to measurable quantities (peak temperatures, cooling rates, radioisotope closure times) in meteorites that were determined by their thermal histories. C1 Univ Tennessee, Dept Geol Sci, Knoxville, TN 37996 USA. Univ Tennessee, Planetary Geosci Inst, Knoxville, TN 37996 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Planetary Sci Inst, Tucson, AZ 85705 USA. RP Ghosh, A (reprint author), Univ Tennessee, Dept Geol Sci, Knoxville, TN 37996 USA. NR 45 TC 38 Z9 38 U1 0 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 MAY PY 2003 VL 38 IS 5 BP 711 EP 724 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 721WW UT WOS:000185342300003 ER PT J AU Ivanov, AV Kononkova, NN Yang, SV Zolensky, ME AF Ivanov, AV Kononkova, NN Yang, SV Zolensky, ME TI The Kaidun meteorite: Clasts of alkaline-rich fractionated materials SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID NEW-SOUTH-WALES; CRYSTALLIZATION; SHERGOTTITE; MINERALOGY; METAMORPHISM; AENIGMATITE; PETROLOGY; AUSTRALIA; SYENITES; VOLCANO AB Clasts of alkaline (the second find in meteorites) and subalkaline rocks were found in the Kaidun meteorite. One of them (#d4A) is a large crystal of albite with inclusions of fluorapatite, arfvedsonite, aenigmatite, and wilkinsonite. The two latter minerals were previously unknown in meteorites. Another clast (#d[3-5]D) has a melt crystallization texture of mainly feldspar (oligoclase) composition and contains relict grains of both high-Ca and low-Ca pyroxene and fluorapatite. The mineralogical characteristics of these clasts suggest a genetic relationship and an origin from the same parent body. The textural and mineralogical characteristics of the clasts indicate origin by extensive igneous differentiation. Such processes most likely took place in a rather large differentiated body. The material of clast #d(3-5)D is similar in some mineralogical respects to basaltic shergottites. C1 VI Vernadskii Inst Geochem & Analyt Chem, Moscow 117975, Russia. Lockheed Engn & Sci Co, Houston, TX 77258 USA. NASA, Lyndon B Johnson Space Ctr, SN2, Houston, TX 77058 USA. RP Ivanov, AV (reprint author), VI Vernadskii Inst Geochem & Analyt Chem, Moscow 117975, Russia. NR 31 TC 11 Z9 12 U1 0 U2 0 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 2003 VL 38 IS 5 BP 725 EP 737 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 721WW UT WOS:000185342300004 ER PT J AU Ghaffarian, R AF Ghaffarian, R TI Qualification approaches and thermal cycle test results for CSP/BGA/FCBGA SO MICROELECTRONICS RELIABILITY LA English DT Article AB Qualification of newly developed multifunctional electronic packages, e.g. system in a package (SIP), are becoming complex at the package level and even more at the assembly and system levels. After many years of data collection, just recently industry agreed to release an industry-wide specification for single die area array package assembly qualification. Probability risk assessment, being implemented by NASA for space flight missions, may be narrowed at the element level for advanced electronic systems and SIP, and further narrowed at the electronic subsystem level. This paper will review the key elements of an industry-wide specification recently published by the IPC (association connecting electronics industries). It will report on a few other unique qualification approaches that are currently being either implemented or developed for risk reduction in high reliability applications. Risk level assessment based 2-P, 3-P, and LogNormal distributions will be compared for plastic ball grid array (PBGA) and flip chip BGA (FCBGA). For this case, risks are compared using cycles-to-failures (CTFs) test results for temperature ranges of -30 to 100 degreesC and 0 to 100 degreesC (two profiles). In addition, CTFs up to 1,500 cycles in the range of -55 to 125 degreesC for a 784 I/O FCBGA (flip chip BGA, a 175 I/O FPBGA (fine pitch BGA)), and a 313 I/O PBGA (plastic BGA) are compared. Inspection results along with scanning electron microscopy and optical cross-sectional photos revealing damage and failure mechanisms are also included. (C) 2003 Elsevier Science. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91100 USA. RP Ghaffarian, R (reprint author), CALTECH, Jet Prop Lab, MS 125-152 4800 Oak Grove Dr, Pasadena, CA 91100 USA. EM reza.ghaffrian@jpl.nasa.gov NR 13 TC 15 Z9 15 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0026-2714 J9 MICROELECTRON RELIAB JI Microelectron. Reliab. PD MAY PY 2003 VL 43 IS 5 BP 695 EP 706 DI 10.1016/S0026-2714(03)00053-2 PG 12 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 680GA UT WOS:000182966900002 ER PT J AU Mapes, BE Warner, TT Xu, M Negri, AJ AF Mapes, BE Warner, TT Xu, M Negri, AJ TI Diurnal patterns of rainfall in northwestern South America. Part I: Observations and context SO MONTHLY WEATHER REVIEW LA English DT Article ID CONVECTIVE CLOUDINESS; TROPICAL RAINFALL; LIFE-CYCLE; WARM POOL; PRECIPITATION; SATELLITE; SYSTEMS; COAST AB One of the rainiest areas on earth, the Panama Bight and Pacific (western) littoral of Colombia, is the focal point for a regional modeling study utilizing the fifth-generation Pennsylvania State University-NCAR Mesoscale Model (MM5) with nested grids. In this first of three parts, the observed climatology of the region is presented. The seasonal march of rainfall has a northwest-southeast axis, with western Colombia near the center, receiving rain throughout the year. This study focuses on the August-September season. The diurnal cycle of rainfall over land exhibits an afternoon maximum over most of South and Central America, typically composed of relatively small convective cloud systems. Over some large valleys in the Andes, and over Lake Maracaibo, a nocturnal maximum of rainfall is observed. A strong night/morning maximum of rainfall prevails over the coastal ocean, propagating offshore and westward with time. This offshore convection often takes the form of mesoscale convective systems with sizes comparable to the region's coastal concavities and other geographical features. The 10-day period of these model studies (28 August-7 September 1998) is shown to be a period of unusually active weather, but with a time-mean rainfall pattern similar to longer-term climatology. It is concluded that the rain-producing processes during this time period are likely to be typical of those that shape the seasonal climatology. C1 Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Climate Diagnost Ctr,UCB 216, Boulder, CO 80309 USA. Univ Colorado, Program Atmospher & Ocean Sci, Boulder, CO 80309 USA. Natl Ctr Atmospher Res, Res Applicat Program, Boulder, CO 80307 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Mapes, BE (reprint author), Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Climate Diagnost Ctr,UCB 216, Boulder, CO 80309 USA. RI Mapes, Brian/A-5647-2010 NR 44 TC 79 Z9 87 U1 3 U2 13 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 2003 VL 131 IS 5 BP 799 EP 812 DI 10.1175/1520-0493(2003)131<0799:DPORIN>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 666HQ UT WOS:000182172000004 ER PT J AU Ferreira, RN Rickenbach, TM Herdies, DL Carvalho, LMV AF Ferreira, RN Rickenbach, TM Herdies, DL Carvalho, LMV TI Variability of South American convective cloud systems and tropospheric circulation during January-March 1998 and 1999 SO MONTHLY WEATHER REVIEW LA English DT Article ID UNITED-STATES; EL-NINO; GLOBAL PRECIPITATION; LIFE-CYCLE; COMPLEXES; RAINFALL; SUMMER; OSCILLATION; CLIMATE; MODEL AB A comparison of the submonthly variability of atmospheric circulation and organization of convection in South America during January-February-March of 1998 (JFM98) and January-February-March of 1999 (JFM99) is presented. According to the National Centers for Environmental Prediction reanalysis, the South American low-level jet (SALLJ) was about twice as strong during JFM of the 1998 El Nino episode than during JFM of the 1999 La Nina episode. The difference in SALLJ strength between these two years translated into stronger transport of moist tropical air into the subtropics during JFM98 than during JFM99. An objective tracking technique was used to identify large, long-lived convective cloud systems in infrared imagery. The stronger SALLJ was accompanied by larger and more numerous long-lived convective cloud systems and nearly twice as much rainfall in subtropical South America (parts of southern Brazil, Uruguay, and Argentina) during JFM98 than during JFM99. The difference between JFM98 and JFM99 SALLJ strength in Bolivia is in part explained by submonthly variability associated with the South Atlantic convergence zone (SACZ). Periods when the SACZ is present are marked by southerly or weak northerly winds in Bolivia. The South Atlantic convergence zone was more prominent during JFM99 than during JFM98 contributing to a weaker SALLJ during JFM99. Large, long-lived convective cloud systems in subtropical South America tended to occur during times when the SACZ was absent and the SALLJ was strong over Bolivia. Interannual variability associated with the El Nino-Southern Oscillation also contributed to the observed interannual variability of the SALLJ in Bolivia. In the tropical portions of South America nearly 6 times more large, long-lived convective cloud systems were observed during JFM99 than during JFM98. This was accompanied by more plentiful precipitation in portions of the Amazon basin and in the Bolivian Altiplano during JFM99 than during JFM98. Interannual variability associated with the El Nino-Southern Oscillation was an important contributor to the observed convective cloud system and precipitation differences in tropical South America. C1 NASA, Goddard Space Flight Ctr, Seasonal Interannual Predict Project, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Mesoscale Proc Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. Univ Calif Santa Barbara, Inst Computat Earth Syst Sci, Santa Barbara, CA 93106 USA. RP Ferreira, RN (reprint author), NASA, Goddard Space Flight Ctr, Seasonal Interannual Predict Project, Code 913, Greenbelt, MD 20771 USA. RI Carvalho, Leila/I-5027-2012; Herdies, Dirceu/C-6675-2013 OI Herdies, Dirceu/0000-0002-2872-8453 NR 42 TC 28 Z9 30 U1 0 U2 0 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 2003 VL 131 IS 5 BP 961 EP 973 DI 10.1175/1520-0493(2003)131<0961:VOSACC>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 666HQ UT WOS:000182172000013 ER PT J AU Li, J Ng, HT Cassell, A Fan, W Chen, H Ye, Q Koehne, J Han, J Meyyappan, M AF Li, J Ng, HT Cassell, A Fan, W Chen, H Ye, Q Koehne, J Han, J Meyyappan, M TI Carbon nanotube nanoelectrode array for ultrasensitive DNA detection SO NANO LETTERS LA English DT Article ID ELECTRON-TRANSFER; ELECTROCHEMISTRY; FABRICATION AB A nanoelectrode array based on vertically aligned multiwalled carbon nanotubes (MWNTs) embedded in SiO2 is used for ultrasensitive DNA detection. Characteristic electrochemical behaviors are observed for measuring bulk and surface-immobilized redox species. Sensitivity is dramatically improved by lowering the nanotube density. Oligonucleotide probes are selectively functionalized to the open ends of nanotubes. The hybridization of subattomole DNA targets can be detected by combining such electrodes with Ru(bpy)(3)(2+) mediated guanine oxidation. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Li, J (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RI Li, Jun/H-7771-2013 OI Li, Jun/0000-0002-3689-8946 NR 22 TC 489 Z9 498 U1 8 U2 106 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 2003 VL 3 IS 5 BP 597 EP 602 DI 10.1021/nl0340677 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 681MN UT WOS:000183040100007 ER PT J AU Khare, B Meyyappan, M Moore, MH Wilhite, P Imanaka, H Chen, B AF Khare, B Meyyappan, M Moore, MH Wilhite, P Imanaka, H Chen, B TI Proton irradiation of carbon nanotubes SO NANO LETTERS LA English DT Article ID ION-IRRADIATION; RADIATION; DEFECTS AB Single-walled carbon nanotubes (SWNTs) were irradiated with 1 MeV protons and the samples were analyzed using Fourier transform infrared spectroscopy, UV-vis-NIR spectroscopy, Raman spectroscopy, and secondary ion mass spectrometry. There is clear evidence that the irradiated sample contains C-H bonds. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. ELORET Corp, Sunnyvale, CA 94087 USA. RP Meyyappan, M (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RI Imanaka, Hiroshi/E-7816-2012 NR 17 TC 53 Z9 53 U1 0 U2 15 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 2003 VL 3 IS 5 BP 643 EP 646 DI 10.1021/nl034058y PG 4 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 681MN UT WOS:000183040100016 ER PT J AU Zhao, JJ Buia, CL Han, J Lu, JP AF Zhao, JJ Buia, CL Han, J Lu, JP TI Quantum transport properties of ultrathin silver nanowires SO NANOTECHNOLOGY LA English DT Article ID ELECTRON-MICROSCOPIC CHARACTERIZATION; TOTAL-ENERGY CALCULATIONS; SCALE METALLIC CONTACTS; WAVE BASIS-SET; CARBON NANOTUBES; CONDUCTANCE QUANTIZATION; MOLECULAR-DYNAMICS; POINT-CONTACT; GOLD ATOMS; SINGLE AB The quantum transport properties of ultrathin silver nanowires are investigated. For a perfect crystalline nanowire with four atoms per unit cell, three conduction channels are found, corresponding to three s bands crossing the Fermi level. One conductance channel is disrupted by a single-atom defect. either adding or removing one atom. The quantum interference effect leads to oscillation of conductance versus the inter-defect distance. In the presence of a multiple-atom defect, one conduction channel remains robust at the Fermi level regardless the details of defect configuration. The histogram of conductance calculated for a finite nanowire (seven atoms per cross section) with a large number of random defect configurations agrees well with recent experiments. C1 Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. NASA, Eloret Corp, Ames Res Ctr, Santa Clara, CA 95051 USA. RP Lu, JP (reprint author), Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. RI Zhao, Jijun/I-6030-2015 NR 39 TC 63 Z9 65 U1 3 U2 23 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 2003 VL 14 IS 5 BP 501 EP 504 AR PII S0957-4484(03)56786-1 DI 10.1088/0957-4484/14/5/304 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Science & Technology - Other Topics; Materials Science; Physics GA 688CC UT WOS:000183414000005 ER PT J AU Levine, JS AF Levine, JS TI Atmospheric chemistry: Burning domestic issues SO NATURE LA English DT Editorial Material C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Levine, JS (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 5 TC 7 Z9 7 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 MAY 1 PY 2003 VL 423 IS 6935 BP 28 EP 29 DI 10.1038/423028a PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 673CG UT WOS:000182561600028 PM 12721613 ER PT J AU Gallaway, BJ Cole, JG Martin, LR Nance, JM Longnecker, M AF Gallaway, BJ Cole, JG Martin, LR Nance, JM Longnecker, M TI Description of a simple electronic logbook designed to measure effort in the Gulf Of Mexico shrimp fishery SO NORTH AMERICAN JOURNAL OF FISHERIES MANAGEMENT LA English DT Article AB The magnitude and spatial distribution of fishing effort in the Gulf of Mexico penaeid shrimp fishery has been the subject of great contention. Here, we describe a simple and inexpensive electronic logbook (ELB) and algorithms tested to describe the temporal and spatial patterns of fishing effort, based on nothing more than the position of the vessel at 10-min intervals; these algorithms were tested with 788 tows (4,558 h of trawling). On average, the difference between ELB estimates and recorded levels of effort were less than 1%; spatial agreement was also good. On a spatial basis, ELB estimates accounted for more than 84-97% of the variance observed in recorded effort, depending on the grid size used in the analysis. Further, analysis of data from more than 18,000 tows yielded a strong within-trip relationship between catch and effort. This relationship enables accurate allocation of the total landings from a trip to the subareas fished, based on nothing more than trawling times within each subarea fished. Because National Marine Fisheries Service port agents already collect landings on a trip total basis, a large-scale installation of inexpensive (2.0.CO;2 PG 9 WC Fisheries SC Fisheries GA 686UG UT WOS:000183338900022 ER PT J AU Beiersdorfer, P Behar, E Boyce, KR Brown, GV Chen, H Gendreau, KC Graf, A Gu, MF Harris, CL Kahn, SM Kelley, RL Lepson, JK May, MJ Neill, PA Pinnington, EH Porter, FS Smith, AJ Stahle, CK Szymkowiak, AE Tillotson, A Thorn, DB Trabert, E Wargelin, BJ AF Beiersdorfer, P Behar, E Boyce, KR Brown, GV Chen, H Gendreau, KC Graf, A Gu, MF Harris, CL Kahn, SM Kelley, RL Lepson, JK May, MJ Neill, PA Pinnington, EH Porter, FS Smith, AJ Stahle, CK Szymkowiak, AE Tillotson, A Thorn, DB Trabert, E Wargelin, BJ TI Overview of the Livermore electron beam ion trap project SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 11th International Conference on the Physics of Highly Charged Ions (HCI 2002) CY SEP 01-06, 2002 CL CAEN, FRANCE DE electron beam ion trap; SuperEBIT; microcalorimeter; spectroscopy (X-ray and optical) ID M1 TRANSITION RATES; HIGH-RESOLUTION; FE-XVII; LINES; MICROCALORIMETER; SPECTROMETER; INTENSITY AB The Livermore electron beam ion trap facility has recently been moved to a new location within LLNL, and new instrumentation was added, including a 32-pixel microcalorimeter. The move was accompanied by a shift of focus toward in situ measurements of highly charged ions, which continue with increased vigor. Overviews of the facility, which includes EBIT-I and SuperEBIT, and the research projects are given, including results from optical spectroscopy, QED, and X-ray line excitation measurements. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Columbia Univ, New York, NY 10027 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Davis, Davis, CA 95616 USA. MIT, Cambridge, MA 02139 USA. Univ Nevada, Reno, NV 89557 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Univ Alberta, Edmonton, AB T6G 2J1, Canada. Morehouse Coll, Atlanta, GA 30314 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Beiersdorfer, P (reprint author), Lawrence Livermore Natl Lab, L-260, Livermore, CA 94550 USA. RI Porter, Frederick/D-3501-2012; Kelley, Richard/K-4474-2012 OI Porter, Frederick/0000-0002-6374-1119; NR 31 TC 11 Z9 11 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 2003 VL 205 BP 173 EP 177 DI 10.1016/S0168-583X(03)00941-8 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 684MM UT WOS:000183211200032 ER PT J AU Mackey, JR Salari, E Tin, P AF Mackey, JR Salari, E Tin, P TI Modulation, alignment, and calibration methods for phase-modulated optical polarimeters SO OPTICAL ENGINEERING LA English DT Article DE polarization; calibration; phase retardance; modulation ID CRYSTAL AB We have studied, assembled, and tested several different types of phase-modulated optical polarimeters capable of transient stress and molecular orientation angle measurements in complex optically anisotropic fluids and materials. The main difference in the instrumentation lies in the applied modulation technique. Three different phase modulation techniques are studied in this paper: the photoelastic effect, the transverse electro-optic effect, and liquid-crystal variable retardation modulation schemes. The precise measurement of a material's retardance and average molecular orientation angle depends on an accurate alignment and calibration within the range of the chosen modulator. Therefore, we address some of the issues associated with the choice of phase modulator as well as applicable alignment and calibration techniques. We also study and test several methods that may be used to ameliorate these issues. (C) 2003 Society of Photo-Optical Instrumentation Engineers. C1 MK Opt Inc, Concord Township, OH 44077 USA. Univ Toledo, Dept Elect Engn & Comp Sci, Toledo, OH 43606 USA. NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. RP Mackey, JR (reprint author), MK Opt Inc, 10473 Misty Ridge, Concord Township, OH 44077 USA. NR 12 TC 2 Z9 3 U1 0 U2 2 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 2003 VL 42 IS 5 BP 1460 EP 1466 DI 10.1117/1.1563234 PG 7 WC Optics SC Optics GA 680PE UT WOS:000182985900040 ER PT J AU Rudnick, J Barmatz, M Zhong, F AF Rudnick, J Barmatz, M Zhong, F TI Test of a new field-theoretical crossover equation of state SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 23rd International Conference on Low Temperature Physics (LT23) CY AUG 20-27, 2002 CL HIROSHIMA, JAPAN SP Int Union Pure & Appl Phys, Sci Council Japan, Phys Soc Japan, Japan Soc Appl Phys, Cryogen Assoc Japan DE equation of state; critical phenomena; liquid-gas critical point; He-3 thermodynamic properties ID CRITICAL-POINT; HE-3 AB A new field-theoretical crossover equation-of-state model provides a bridge between the asymptotic behavior close to a liquid gas critical point and the expected mean field behavior farther away. The crossover is based on the beta function for the renormalized fourth-order coupling constant and incorporates the correct asymptotic, crossover, and mean field exponents. Experimental measurements of the isothermal susceptibility, coexistence curve, and heat capacity at constant volume near the He-3 critical point compare well with the predictions of this model. (C) 2003 Elsevier Science B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. RP Barmatz, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 1 Z9 1 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD MAY PY 2003 VL 329 BP 110 EP 111 DI 10.1016/S0921-4526(02)01908-7 PG 2 WC Physics, Condensed Matter SC Physics GA 684UC UT WOS:000183224100047 ER PT J AU Nash, A Larson, M Panek, J Mulders, N AF Nash, A Larson, M Panek, J Mulders, N TI Phase separation study near the tricritical point in He-3-He-4 mixtures SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 23rd International Conference on Low Temperature Physics (LT23) CY AUG 20-27, 2002 CL HIROSHIMA, JAPAN SP Int Union Pure & Appl Phys, Sci Council Japan, Phys Soc Japan, Japan Soc Appl Phys, Cryogen Assoc Japan DE He-3-He-4 mixtures; tricritical point AB We are studying phase separation in He-3-He-4 mixtures using inter-digital capacitor (IDC) sensors located on the top of our cell. The IDCs measure the phase separation by probing the local concentration near each sensor. The IDCs were developed as part of our effort to eventually perform similar measurements on the International Space Station, in the absence of the stabilizing influence of gravity. The IDCs appear to be well suited for making measurements of the phase separation on both sides of the tricritical point, including on the He-3 rich side of the phase diagram where they observe the minority He-4 rich phase forming a macroscopic thick film at phase separation. (C) 2003 Elsevier Science B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Delaware, Newark, DE 19716 USA. RP Nash, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 79-24, Pasadena, CA 91109 USA. NR 7 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD MAY PY 2003 VL 329 BP 160 EP 161 DI 10.1016/S0921-4526(02)01951-8 PG 2 WC Physics, Condensed Matter SC Physics GA 684UC UT WOS:000183224100069 ER PT J AU Limketkai, B Granger, J Weilert, M Hahn, I AF Limketkai, B Granger, J Weilert, M Hahn, I TI A digital SQUID controller SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 23rd International Conference on Low Temperature Physics (LT23) CY AUG 20-27, 2002 CL HIROSHIMA, JAPAN SP Int Union Pure & Appl Phys, Sci Council Japan, Phys Soc Japan, Japan Soc Appl Phys, Cryogen Assoc Japan DE SQUID; DSP; flux-locked loop AB We describe the performance of an improved DC SQUID controller base upon a PC data acquisition board with a single digital signal processor (DSP). The main DSP algorithm, which handles the flux-locked-loop, is optimally written in assembly language. To improve the performance of the controller, we have added a custom built frequency converter circuit that matches the modulation frequency of the DSP system to that of a commercial SQUID sensor and preamplifier. The noise level of the DC SQUID controller system is comparable with a commercial analog system, similar to4muPhi(0)/rootHz at 100 Hz. The current system could control up to 5 SQUID channels. (C) 2003 Elsevier Science B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hahn, I (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM inseob.hahn@jpl.nasa.gov NR 3 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD MAY PY 2003 VL 329 BP 1506 EP 1507 DI 10.1016/S0921-4526(02)02412-2 PN 2 PG 2 WC Physics, Condensed Matter SC Physics GA 694YK UT WOS:000183802700503 ER PT J AU Larson, M Croonquist, A Dick, GJ Liu, YM AF Larson, M Croonquist, A Dick, GJ Liu, YM TI The science capability of the Low Temperature Microgravity Physics Facility SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 23rd International Conference on Low Temperature Physics (LT23) CY AUG 20-27, 2002 CL HIROSHIMA, JAPAN SP Int Union Pure & Appl Phys, Sci Council Japan, Phys Soc Japan, Japan Soc Appl Phys, Cryogen Assoc Japan DE superfluid; dewar; space-based experiment; He-4 ID LAMBDA-POINT; HELIUM; HEAT AB The Low Temperature Microgravity Physics Facility (LTMPF) is a multiple user and multiple-flight NASA facility that will provide a low temperature environment for about 4.5 months on board the International Space Station (ISS). The LTMPF will be attached to the Japanese Experiment Module (KIBO) Exposed Facility of the ISS. The Jet Propulsion Laboratory is developing the Facility for its initial flight in late 2005. The LTMPF will provide a reusable platform to enable state of the art experiments requiring both low temperatures and microgravity conditions. During each mission, two distinct primary experiments will be accommodated, as well as secondary experiments that can utilize the as built hardware. (C) 2003 Elsevier Science B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Larson, M (reprint author), CALTECH, Jet Prop Lab, Mail Stop 79-24,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD MAY PY 2003 VL 329 BP 1588 EP 1589 DI 10.1016/S0921-4526(02)02304-9 PN 2 PG 2 WC Physics, Condensed Matter SC Physics GA 694YK UT WOS:000183802700538 ER PT J AU Kamiya, K Warner, BA DiPirro, MJ Numazawa, T AF Kamiya, K Warner, BA DiPirro, MJ Numazawa, T TI Passive magnetic shielding for the submillimeter and far infrared experiment SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 23rd International Conference on Low Temperature Physics (LT23) CY AUG 20-27, 2002 CL HIROSHIMA, JAPAN SP Int Union Pure & Appl Phys, Sci Council Japan, Phys Soc Japan, Japan Soc Appl Phys, Cryogen Assoc Japan DE SQUID; ADR; passive shielding; salt pill AB Goddard Space Flight Center is developing the submillimeter and far infrared experiment (SAFIRE). SAFIRE will use SQUIDs as amplifiers for detectors, which must be shielded from the magnet cooling system, an adiabatic demagnetization refrigerator (ADR). The magnetic field at the detector package must remain at or below the 10(-7) tesla level while the detectors are operating. We discuss laboratory tests of the passive shielding and simulations. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Natl Inst Mat Sci, Tsukuba Magnet Lab, Tsukuba, Ibaraki 3050003, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kamiya, K (reprint author), Natl Inst Mat Sci, Tsukuba Magnet Lab, 3-13 Sakura, Tsukuba, Ibaraki 3050003, Japan. NR 2 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD MAY PY 2003 VL 329 BP 1627 EP 1628 DI 10.1016/s0921-4526(02)02432-8 PN 2 PG 2 WC Physics, Condensed Matter SC Physics GA 694YK UT WOS:000183802700557 ER PT J AU Lee, MC Israelsson, UE AF Lee, MC Israelsson, UE TI Fundamental physics research aboard the international space station SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 23rd International Conference on Low Temperature Physics (LT23) CY AUG 20-27, 2002 CL HIROSHIMA, JAPAN SP Int Union Pure & Appl Phys, Sci Council Japan, Phys Soc Japan, Japan Soc Appl Phys, Cryogen Assoc Japan DE space station experiments; low temperature physics; laser cooling; atomic clock AB NASAs research plans aboard the International Space Station (ISS) are discussed. Experiments in low temperature physics and atomic physics are planned to commence in late 2005. Experiments in gravitational physics are planned to begin in 2007. A low temperature microgravity physics facility is under development for the low temperature and gravitation experiments. The facility provides a 2 K environment for two instruments and an experimental lifetime of 4.5 months. Each instrument will be capable of accomplishing a primary investigation and one or more guest investigations. Experiments on the first flight will study non-equilibrium phenomena near the superfluid 4He transition and measure scaling parameters near the 3He critical point. Experiments on the second flight will investigate boundary effects near the superfluid 4He transition and perform a red-shift test of Einstein's theory of general relativity. Follow-on flights of the facility will occur at 16 to 22-month intervals. The first couple of atomic physics experiments will take advantage of the free-fall environment to operate laser cooled atomic fountain clocks with 10-100 times better performance than any Earth based clock. These clocks will be used for experimental studies in General and Special Relativity. Flight definition experiment studies are underway by investigators studying Bose Einstein Condensates and use of atom interferometers as potential future flight candidates. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, Washington, DC 20546 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, MC (reprint author), NASA, Code UG, Washington, DC 20546 USA. NR 0 TC 2 Z9 4 U1 2 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD MAY PY 2003 VL 329 BP 1649 EP 1650 DI 10.1016/S0921-4526(02)02441-9 PN 2 PG 2 WC Physics, Condensed Matter SC Physics GA 694YK UT WOS:000183802700566 ER PT J AU Beacom, JF Palomares-Ruiz, S AF Beacom, JF Palomares-Ruiz, S TI Neutral-current atmospheric neutrino flux measurement using neutrino-proton elastic scattering in Super-Kamiokande SO PHYSICAL REVIEW D LA English DT Article ID NUCLEAR DECAY SIGNATURES; OSCILLATION SOLUTIONS; TAU-APPEARANCE; FORM-FACTOR; RATIO; DETECTOR; ENERGY; EVENTS; MUONS; WEAK AB Recent results show that atmospheric nu(mu) oscillate with deltam(2) similar or equal to 3x10(-3) eV(2) and sin(2)2theta(atm)similar or equal to1, and that conversion into nu(e) is strongly disfavored. The Super-Kamiokande (SK) Collaboration, using a combination of three techniques, reports that their data favor nu(mu) --> nu(tau) over nu(mu) --> nu(sterile). This distinction is extremely important for both four-neutrino models and cosmology. We propose that neutrino-proton elastic scattering (nu+p --> nu+p) in water Cerenkov detectors can also distinguish between active and sterile oscillations. This was not previously recognized as a useful channel since only about 2% of struck protons are above the Cerenkov threshold. Nevertheless, in the present SK data there should be about 40 identifiable events. We show that these events have unique particle identification characteristics, point in the direction of the incoming neutrinos, and correspond to a narrow range of neutrino energies (1-3 GeV, oscillating near the horizon). This channel will be particularly important in Hyper-Kamiokande, with similar to40 times higher rate. Our results have other important applications. First, for a similarly small fraction of atmospheric neutrino quasielastic events, the proton is relativistic. This uniquely selects nu(mu) (not (nu) over bar (mu)) events, useful for understanding matter effects, and allows determination of the neutrino energy and direction, useful for the L/E dependence of oscillations. Second, using accelerator neutrinos, both elastic and quasielastic events with relativistic protons can be seen in the K2K 1-kton near detector and MiniBooNE. C1 Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Univ Valencia, Dept Fis Teor, E-46100 Valencia, Spain. RP Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, POB 500, Batavia, IL 60510 USA. EM beacom@fnal.gov; Sergio.Palomares@uv.es RI Palomares-Ruiz, Sergio/K-8048-2014; OI Palomares-Ruiz, Sergio/0000-0001-9049-2288; Beacom, John/0000-0002-0005-2631 NR 68 TC 10 Z9 10 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 1 PY 2003 VL 67 IS 9 AR 093001 DI 10.1103/PhysRevD.67.093001 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 686GL UT WOS:000183313000011 ER PT J AU Yong, WA Luo, LS AF Yong, WA Luo, LS TI Nonexistence of H theorems for the athermal lattice Boltzmann models with polynomial equilibria SO PHYSICAL REVIEW E LA English DT Article ID NAVIER-STOKES EQUATION; NUMERICAL SIMULATIONS; NONPERTURBATIVE EQUILIBRIA; PARTICULATE SUSPENSIONS; KINETIC-EQUATIONS; NONIDEAL GASES; AUTOMATA; FLOWS AB We prove that no H theorem exists for the athermal lattice Boltzmann equation with polynomial equilibria satisfying the conservation laws exactly and explicitly. The proof is demonstrated by using the seven-velocity model in a triangular lattice in two dimensions, and can be readily extended to other lattice Boltzmann models in two and three dimensions. Some issues pertinent to the numerical instabilities of the lattice Boltzmann method are disscussed. C1 Univ Heidelberg, IWR, D-69120 Heidelberg, Germany. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Yong, WA (reprint author), Univ Heidelberg, IWR, Neuenheimer Feld 294, D-69120 Heidelberg, Germany. EM yong.wen-an@iwr.uni-heidelberg.de; luo@nianet.org RI yong, wen-an/H-7601-2012; Luo, Li-Shi/A-4561-2011 OI yong, wen-an/0000-0003-4440-128X; Luo, Li-Shi/0000-0003-1215-7892 NR 41 TC 21 Z9 21 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 2003 VL 67 IS 5 AR 051105 DI 10.1103/PhysRevE.67.051105 PN 1 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 689GA UT WOS:000183482200014 PM 12786132 ER PT J AU Stern, DP AF Stern, DP TI Nearest star: The surprising science of our Sun SO PHYSICS IN PERSPECTIVE LA English DT Book Review C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Stern, DP (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 695, Greenbelt, MD 20771 USA. NR 1 TC 0 Z9 0 U1 0 U2 2 PU BIRKHAUSER VERLAG AG PI BASEL PA VIADUKSTRASSE 40-44, PO BOX 133, CH-4010 BASEL, SWITZERLAND SN 1422-6944 J9 PHYS PERSPECT JI Phys. Perspect. PD MAY PY 2003 VL 5 IS 2 BP 238 EP 239 PG 2 WC History & Philosophy Of Science SC History & Philosophy of Science GA 691BN UT WOS:000183585100008 ER PT J AU Mather, JC Page, L Peebles, PJE AF Mather, JC Page, L Peebles, PJE TI David Todd Wilkinson - Obituary SO PHYSICS TODAY LA English DT Biographical-Item C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Princeton Univ, Princeton, NJ 08544 USA. RP Mather, JC (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 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 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAY PY 2003 VL 56 IS 5 BP 76 EP 77 DI 10.1063/1.1583543 PG 2 WC Physics, Multidisciplinary SC Physics GA 673JE UT WOS:000182576300023 ER PT J AU Grande, M Browning, R Waltham, N Parker, D Dunkin, SK Kent, B Kellett, B Perry, CH Swinyard, B Perry, A Feraday, J Howe, C McBride, G Phillips, K Huovelin, J Muhli, P Hakala, PJ Vilhu, O Laukkanen, J Thomas, N Hughes, D Alleyne, H Grady, M Lundin, R Barabash, S Baker, D Clark, PE Murray, CD Guest, J Casanova, I d'Uston, LC Maurice, S Foing, B Heather, DJ Fernandes, V Muinonen, K Russell, SS Christou, A Owen, C Charles, P Koskinen, H Kato, M Sipila, K Nenonen, S Holmstrom, M Bhandari, N Elphic, R Lawrence, D AF Grande, M Browning, R Waltham, N Parker, D Dunkin, SK Kent, B Kellett, B Perry, CH Swinyard, B Perry, A Feraday, J Howe, C McBride, G Phillips, K Huovelin, J Muhli, P Hakala, PJ Vilhu, O Laukkanen, J Thomas, N Hughes, D Alleyne, H Grady, M Lundin, R Barabash, S Baker, D Clark, PE Murray, CD Guest, J Casanova, I d'Uston, LC Maurice, S Foing, B Heather, DJ Fernandes, V Muinonen, K Russell, SS Christou, A Owen, C Charles, P Koskinen, H Kato, M Sipila, K Nenonen, S Holmstrom, M Bhandari, N Elphic, R Lawrence, D TI The D-CIXS X-ray mapping spectrometer on SMART-1 SO PLANETARY AND SPACE SCIENCE LA English DT Article AB The D-CIXS Compact X-ray Spectrometer will provide high quality spectroscopic mapping of the Moon, the primary science target of the ESA SMART-1 mission. D-CIXS consists of a high throughput spectrometer, which will perform spatially localised X-ray fluorescence spectroscopy. It will also carry a solar monitor, to provide the direct calibration needed to produce a global map of absolute lunar elemental abundances, the first time this has been done. Thus it will achieve ground breaking science within a resource envelope far smaller than previously thought possible for this type of instrument, by exploiting two new technologies, swept charge devices and micro-structure collimators. The new technology does not require cold running, with its associated overheads to the spacecraft. At the same time it will demonstrate a radically novel approach to building a type of instrument essential for the BepiColombo mission and potential future planetary science targets. (C) 2003 Published by Elsevier Science Ltd. C1 Rutherford Appleton Lab, Space Sci & Technol Dept, Didcot OX11 0QX, Oxon, England. UCL, Dept Earth Sci, London WC1E 6BT, England. UCL, Dept Phys & Astron, London WC1E 6BT, England. Univ Helsinki Observ, FIN-00014 Helsinki, Finland. Tuorla Observ, FIN-21500 Piikkio, Finland. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Univ Sheffield, Dept Phys & Astron, Sheffield S10 2TN, S Yorkshire, England. Univ Sheffield, Dept Automat Control & Syst Engn, Western Bank, Sheffield S10 2TN, S Yorkshire, England. Nat Hist Museum, London SW7 5BD, England. Swedish Inst Space Phys, SE-98128 Kiruna, Sweden. Atmospher & Space Phys Lab, Boulder, CO 80303 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ London Queen Mary Coll, London E1 4NS, England. Univ Politecn Cataluna, Barcelona 08034, Spain. Ctr Etud Spatiale Rayonnements, F-31028 Toulouse 4, France. Observ Midi Pyrenees, F-31400 Toulouse, France. ESA, Res & Sci Support Dept, Estec, SCI SR, NL-2200 AG Noordwijk, Netherlands. Univ Manchester, Manchester M13 9PL, Lancs, England. Armagh Observ, Armagh BT61 9DG, North Ireland. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. Metorex Int Oy, FIN-02631 Espoo, Finland. Phys Res Lab, Planetary & Geosci Grp, Ahmadabad 380009, Gujarat, India. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. EM m.grande@rl.ac.uk RI Owen, Christopher/C-2999-2008; McBride, Geoff/A-5899-2010; Fernandes, Vera/B-4653-2013; Lawrence, David/E-7463-2015; Grande, Manuel/C-2242-2013; Koskinen, Hannu/B-4971-2017; OI Grady, Monica/0000-0002-4055-533X; Owen, Christopher/0000-0002-5982-4667; Fernandes, Vera/0000-0003-0848-9229; Lawrence, David/0000-0002-7696-6667; Grande, Manuel/0000-0002-2233-2618; Koskinen, Hannu/0000-0003-3839-6461; Casanova, Ignasi/0000-0003-0462-4147; Huovelin, Juhani/0000-0002-6276-5776 NR 9 TC 48 Z9 48 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD MAY PY 2003 VL 51 IS 6 BP 427 EP 433 DI 10.1016/S0032-0633(03)00020-5 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 682JK UT WOS:000183088200009 ER PT J AU Dunkin, SK Grande, M Casanova, I Fernandes, V Heather, DJ Kellett, B Muinonen, K Russell, SS Browning, R Waltham, N Parker, D Kent, B Perry, CH Swinyard, B Perry, A Feraday, J Howe, C Phillips, K McBride, G Huovelin, J Muhli, P Hakala, PJ Vilhu, O Thomas, N Hughes, D Alleyne, H Grady, M Lundin, R Barabash, S Baker, D Clark, PE Murray, CD Guest, J d'Uston, LC Maurice, S Foing, B Christou, A Owen, C Charles, P Laukkanen, J Koskinen, H Kato, M Sipila, K Nenonen, S Holmstrom, M Bhandari, N Elphic, R Lawrence, D AF Dunkin, SK Grande, M Casanova, I Fernandes, V Heather, DJ Kellett, B Muinonen, K Russell, SS Browning, R Waltham, N Parker, D Kent, B Perry, CH Swinyard, B Perry, A Feraday, J Howe, C Phillips, K McBride, G Huovelin, J Muhli, P Hakala, PJ Vilhu, O Thomas, N Hughes, D Alleyne, H Grady, M Lundin, R Barabash, S Baker, D Clark, PE Murray, CD Guest, J d'Uston, LC Maurice, S Foing, B Christou, A Owen, C Charles, P Laukkanen, J Koskinen, H Kato, M Sipila, K Nenonen, S Holmstrom, M Bhandari, N Elphic, R Lawrence, D TI Scientific rationale for the D-CIXS X-ray spectrometer on board ESA's SMART-1 mission to the Moon SO PLANETARY AND SPACE SCIENCE LA English DT Article DE SMART-1; D-CIXS; Moon; X-ray spectroscopy; lunar origin ID POLE AITKEN BASIN; LUNAR; ORIENTALE; MANTLE AB The D-CIXS X-ray spectrometer on ESA's SMART-1 mission will provide the first global coverage of the lunar surface in X-rays, providing absolute measurements of elemental abundances. The instrument will be able to detect elemental Fe, Mg, Al and Si under normal solar conditions and several other elements during solar flare events. These data will allow for advances in several areas of lunar science, including an improved estimate of the bulk composition of the Moon, detailed observations of the lateral and vertical nature of the crust, chemical observations of the maria, investigations into the lunar regolith, and mapping of potential lunar resources. In combination with information to be obtained by the other instruments on SMART-1 and the data already provided by the Clementine and Lunar Prospector missions, this information will allow for a more detailed look at some of the fundamental questions that remain regarding the origin and evolution of the Moon. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Rutherford Appleton Lab, Space Sci & Technol Dept, Didcot OX11 0QX, Oxon, England. UCL, Dept Earth Sci, London WC1E 6BT, England. UCL, Dept Phys & Astron, London WC1E 6BT, England. Univ Politecn Cataluna, Barcelona 08034, Spain. Univ Manchester, Manchester M13 9PL, Lancs, England. ESA, Res & Sci Support Dept, Estec, SCI SR, NL-2200 AG Noordwijk, Netherlands. Univ Helsinki, Univ Helsinki Observ, FIN-00014 Helsinki, Finland. Nat Hist Museum, London SW7 5BD, England. Tuorla Observ, FIN-21500 Piikkio, Finland. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Univ Sheffield, Dept Phys & Astron, Sheffield S10 2TN, S Yorkshire, England. Univ Sheffield, Dept Automat Control & Syst Engn, Sheffield S10 2TN, S Yorkshire, England. Swedish Inst Space Phys, SE-98128 Kiruna, Sweden. Atmospher & Space Phys Lab, Boulder, CO 80303 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Queen Mary Univ London, London E1 4NS, England. Ctr Etud Spatiale Rayonnements, F-31028 Toulouse 4, France. Observ Midi Pyrenees, F-31400 Toulouse, France. Armagh Observ, Armagh BT61 9DG, North Ireland. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. Metorex Int Oy, FIN-02631 Espoo, Finland. Phys Res Lab, Planetary & Geosci Grp, Ahmadabad 380009, Gujarat, India. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Dunkin, SK (reprint author), Rutherford Appleton Lab, Space Sci & Technol Dept, Didcot OX11 0QX, Oxon, England. EM s.k.dunkin@rl.ac.uk RI Owen, Christopher/C-2999-2008; McBride, Geoff/A-5899-2010; Fernandes, Vera/B-4653-2013; Lawrence, David/E-7463-2015; Grande, Manuel/C-2242-2013; Koskinen, Hannu/B-4971-2017; OI Owen, Christopher/0000-0002-5982-4667; Fernandes, Vera/0000-0003-0848-9229; Lawrence, David/0000-0002-7696-6667; Grande, Manuel/0000-0002-2233-2618; Koskinen, Hannu/0000-0003-3839-6461; Huovelin, Juhani/0000-0002-6276-5776 NR 46 TC 18 Z9 18 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD MAY PY 2003 VL 51 IS 6 BP 435 EP 442 DI 10.1016/S0032-0633(03)00019-9 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 682JK UT WOS:000183088200010 ER PT J AU Meyyappan, M Delzeit, L Cassell, A Hash, D AF Meyyappan, M Delzeit, L Cassell, A Hash, D TI Carbon nanotube growth by PECVD: a review SO PLASMA SOURCES SCIENCE & TECHNOLOGY LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; MULTILAYERED METAL-CATALYSTS; SCANNING PROBE MICROSCOPY; SINGLE-WALL; GRAPHITIC NANOFIBERS; PATTERNED GROWTH; GLASS SUBSTRATE; LOW-TEMPERATURE; PLASMA; NUCLEATION AB Carbon nanotubes (CNTs), due to their unique electronic and extraordinary mechanical properties, have been receiving much attention for a wide variety of applications. Recently, plasma enhanced chemical vapour deposition (PECVD) has emerged as a key growth technique to produce vertically-aligned nanotubes. This paper reviews various plasma sources currently used in CNT growth, catalyst preparation and growth results. Since the technology is in its early stages, there is a general lack of understanding of growth mechanisms, the role of the plasma itself, and the identity of key species responsible for growth. This review is aimed at the low temperature plasma research community that has successfully addressed such issues, through plasma and surface diagnostics and modelling, in semiconductor processing and diamond thin film growth. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM meyya@orbit.arc.nasa.gov NR 65 TC 473 Z9 478 U1 22 U2 235 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0963-0252 EI 1361-6595 J9 PLASMA SOURCES SCI T JI Plasma Sources Sci. Technol. PD MAY PY 2003 VL 12 IS 2 BP 205 EP 216 AR PII S0963-0252(03)60688-2 DI 10.1088/0963-0252/12/2/312 PG 12 WC Physics, Fluids & Plasmas SC Physics GA 688XE UT WOS:000183461900012 ER PT J AU Bose, D Rao, MVVS Govindan, TR Meyyappan, M AF Bose, D Rao, MVVS Govindan, TR Meyyappan, M TI Uncertainty and sensitivity, analysis of gas-phase chemistry in a CHF3 plasma SO PLASMA SOURCES SCIENCE & TECHNOLOGY LA English DT Article ID ELECTRON-IMPACT-IONIZATION; 2-DIMENSIONAL FLUID MODEL; CROSS-SECTION SET; DISSOCIATIVE RECOMBINATION; COUPLED PLASMA; C2F6; DISCHARGES; CF4; ION; ATOMS AB A global uncertainty and sensitivity analysis is performed for a detailed gas-phase reaction set in a CHF3 plasma. The goal of this paper is to ascertain the uncertainties in plasma reactor model results (plasma and radical densities) that originate from the uncertainties in the gas-phase chemistry database. We discuss the rates of reactions and their uncertainties. Comparisons with experimental data show that gas-phase rate uncertainties do not explain the disagreements at higher pressures (>30 mTorr). We also find that electron impact dissociation reactions of dominant neutrals are the largest sources of uncertainties. HF kinetics are also found to be critical in determining radical and feedstock gas densities. Relative ion densities are uncertain due to poor understanding of charge transfer mechanisms. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM bose@dm2.arc.nasa.gov NR 46 TC 23 Z9 23 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0963-0252 J9 PLASMA SOURCES SCI T JI Plasma Sources Sci. Technol. PD MAY PY 2003 VL 12 IS 2 BP 225 EP 234 AR PII S0963-0252(03)60938-2 DI 10.1088/0963-0252/12/2/314 PG 10 WC Physics, Fluids & Plasmas SC Physics GA 688XE UT WOS:000183461900014 ER PT J AU Ting, DZY Cartoixa, X Chow, DH Moon, JS Smith, DL McGill, TC Schulman, JN AF Ting, DZY Cartoixa, X Chow, DH Moon, JS Smith, DL McGill, TC Schulman, JN TI Rashba effect resonant tunneling spin filters SO PROCEEDINGS OF THE IEEE LA English DT Article DE interband tunneling; Rashba effect; resonant tunneling; spin filter ID QUANTUM-WELLS; SEMICONDUCTOR HETEROSTRUCTURES; INVERSION ASYMMETRY; INJECTION; RELAXATION; EFFICIENT; TRANSPORT; DYNAMICS AB We propose an InAs/GaSb/AlSb-based asymmetric resonant interband tunneling diode (a-RITD) as a spin filter The device exploits the Rashba effect to achieve spin polarization under zero magnetic field using nonmagnetic III-V semiconductor heterostructures. We discuss the basic principles of the interband tunneling spin filter and present modeling results that demonstrate its advantage. We also propose an implementation procedure for realizing device structure. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Dept Appl Phys, Pasadena, CA 91125 USA. HRL Labs LLC, Malibu, CA 90265 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Ting, DZY (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 32 TC 4 Z9 4 U1 1 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9219 J9 P IEEE JI Proc. IEEE PD MAY PY 2003 VL 91 IS 5 BP 741 EP 751 DI 10.1109/JPROC.2003.811801 PG 11 WC Engineering, Electrical & Electronic SC Engineering GA 681LQ UT WOS:000183038000009 ER PT J AU Giometti, CS Khare, T Tollaksen, SL Tsapin, A Zhu, WH Yates, JR Nealson, KH AF Giometti, CS Khare, T Tollaksen, SL Tsapin, A Zhu, WH Yates, JR Nealson, KH TI Analysis of the Shewanella oneidensis proteome by two-dimensional gel electrophoresis under nondenaturing conditions SO PROTEOMICS LA English DT Article DE electrophoresis; protein; proteome; Shewanella oneidensis ID MALATE-DEHYDROGENASE; PROTEINS; LIPOPROTEINS; METABOLISM; SERUM AB Proteomes are dynamic, i.e., the protein components of living cells change in response to various stimuli. Protein changes can involve shifts in the abundance of protein components, in the interactions of protein components, and in the activity of protein components. Two-dimensional gel electrophoresis (2-DE) coupled with peptide mass spectrometry is useful for the analysis of relative protein abundance, but the denaturing conditions of classical 2-DE do not allow analysis of protein interactions or protein function. We have developed a nondenaturing 2-DE method that allows analysis of protein interactions and protein functions, as demonstrated in our analysis of the cytosol and crude membrane fractions of the facultative anaerobe Shewanella oneidensis MR-1. Our experiments demonstrate that enzymatic activity is retained under the sample and protein separation methods described, as shown by positive malate dehydrogenase activity results. We have also found protein interactions within both the soluble and membrane fractions. The method described will be useful for the characterization of the functional proteomes of microbial systems. C1 Argonne Natl Lab, Biosci Div, Argonne, IL 60439 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Univ So Calif, Los Angeles, CA USA. RP Giometti, CS (reprint author), Argonne Natl Lab, Biosci Div, 9700 S Cass Ave, Argonne, IL 60439 USA. EM csgiometti@anl.gov NR 24 TC 33 Z9 34 U1 0 U2 2 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1615-9853 EI 1615-9861 J9 PROTEOMICS JI Proteomics PD MAY PY 2003 VL 3 IS 5 BP 777 EP 785 DI 10.1002/pmic.200300406 PG 9 WC Biochemical Research Methods; Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 679TA UT WOS:000182937000019 PM 12748955 ER PT J AU Kawata, T Ito, H George, K Wu, HL Uno, T Isobe, K Cucinotta, FA AF Kawata, T Ito, H George, K Wu, HL Uno, T Isobe, K Cucinotta, FA TI Radiation-induced chromosome aberrations in ataxia telangiectasia cells: High frequency of deletions and misrejoining detected by fluorescence in situ hybridization SO RADIATION RESEARCH LA English DT Article ID DOUBLE-STRAND BREAKS; POTENTIALLY LETHAL DAMAGE; NORMAL HUMAN-FIBROBLASTS; IONIZING-RADIATION; DNA-DAMAGE; CHECKPOINT DEFECTS; HUMAN-LYMPHOCYTES; SKIN FIBROBLASTS; GENE-PRODUCT; HEAVY-IONS AB The mechanisms underlying the hyper-radiosensitivity of AT cells were investigated by analyzing chromosome aberrations in the G, and M phases of the cell cycle using a combination of chemically induced premature chromosome condensation (PCC) and fluorescence in situ hybridization (FISH) with chromosome painting probes. Confluent cultures of normal fibroblast cells (AG1522) and fibroblast cells derived from an individual with AT (GM02052) were exposed toy rays and allowed to repair at 37degreesC for 24 h. At doses that resulted in 10% survival, GM02052 cells were approximately five times more sensitive to gamma rays than AG1522 cells. For a given dose, GM02052 cells contained a much higher frequency of deletions and misrejoining than AG1522 cells. For both cell types, a good correlation was found between the percentage of aberrant cells and cell survival. The average number of color junctions, which represent the frequency of chromosome misrejoining, was also found to correlate well with survival. However, in a similar surviving population of GM02052 and AG1522 cells, induced by 1 Gy and 6 Gy, respectively, AG1522 cells contained four times more color junctions and half as many deletions as GM02052 cells. These results indicate that both repair deficiency and misrepair may be involved in the hyper-radiosensitivity of AT cells. (C) 2003 by Radiation Research Society. C1 Chiba Univ, Dept Radiobiol L1, Grad Sch Med, Chuo Ku, Chiba 2608670, Japan. Wyle Lab, Houston, TX USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Kawata, T (reprint author), Chiba Univ, Dept Radiobiol L1, Grad Sch Med, Chuo Ku, 1-8-1 Inohana, Chiba 2608670, Japan. NR 52 TC 14 Z9 19 U1 0 U2 1 PU RADIATION RESEARCH SOC PI OAK BROOK PA 820 JORIE BOULEVARD, OAK BROOK, IL 60523 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD MAY PY 2003 VL 159 IS 5 BP 597 EP 603 DI 10.1667/0033-7587(2003)159[0597:RCAIAT]2.0.CO;2 PG 7 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 674GQ UT WOS:000182629400003 PM 12710870 ER PT J AU Orient, OJ Chutjian, A AF Orient, OJ Chutjian, A TI Baseline resolution of H-1,H-2 and He-3,He-4 isotope mixtures with a Paul ion trap mass spectrometer SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB A Paul ion trap mass spectrometer with fractional resolution of m/Deltam=1565 was constructed and tested. The major improvement in this new trap over that previously reported with m/Deltam=324 [Rev. Sci. Instrum. 73, 2157 (2002)] was due to tighter machining tolerances of the hyperboloidal surfaces, with minor improvement due to better stability of the amplitude of the radio frequency trapping voltage. The present resolution is shown to be sufficient to separate clearly (to baseline) the following masses: He-4(+) and D2+ (0.0256 u separation), He-3(+) and H-3(+) (0.0074 u), He-3(+) and HD+ (0.0059 u), and He-4(2+) and H-2(+) (0.0143 u separation). Resolution of He-4(+) and HT+ (0.0043 u separation) should also be possible, but was not carried out. Resolution of H-3(+) and HD+ (0.0015 u separation) is possible with peaks of comparable intensity, or with deconvolution. (C) 2003 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Orient, OJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 5 Z9 5 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 2003 VL 74 IS 5 BP 2936 EP 2938 DI 10.1063/1.1564277 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 673GB UT WOS:000182570900044 ER PT J AU Rango, A Foster, J Josberger, EG Erbe, EF Pooley, C Wergin, WP AF Rango, A Foster, J Josberger, EG Erbe, EF Pooley, C Wergin, WP TI Rime and graupel: Description and characterization as revealed by low-temperature scanning electron microscopy SO SCANNING LA English DT Article DE field-emission scanning electron microscopy; low-temperature scanning electron microscopy; snow crystals; snowflakes; rime; graupel ID SNOW CRYSTALS; ICE CRYSTALS AB Snow crystals, which form by vapor deposition, occasionally come in contact with supercooled cloud droplets during their formation and descent. When this occurs, the droplets adhere and freeze to the snow crystals in a process known as accretion. During the early stages of accretion, discrete snow crystals exhibiting frozen cloud droplets are referred to as rime. If this process continues, the snow crystal may become completely engulfed in frozen cloud droplets. The resulting particle is known as graupel. Light microscopic investigations have studied rime and graupel for nearly 100 years. However, the limiting resolution and depth of field associated with the light microscope have prevented detailed descriptions of the microscopic cloud droplets and the three-dimensional topography of the rime and graupel particles. This study uses low-temperature scanning electron microscopy to characterize the frozen precipitates that are commonly known as rime and graupel. Rime, consisting of frozen cloud droplets, is observed on all types of snow crystals including needles, columns, plates, and dendrites. The droplets, which vary in size from 10 to 100 mum, frequently accumulate along one face of a single snow crystal, but are found more randomly distributed on aggregations consisting of two or more snow crystals (snowflakes). The early stages of riming are characterized by the presence of frozen cloud droplets that appear as a layer of flattened hemispheres on the surface of the snow crystal. As this process continues, the cloud droplets appear more sinuous and elongate as they contact and freeze to the rimed crystals. The advanced stages of this process result in graupel, a particle 1 to 3 mm across, composed of hundreds of frozen cloud droplets interspersed with considerable air spaces; the original snow crystal is no longer discernible. This study increases our knowledge about the process and characteristics of riming and suggests that the initial appearance of the flattened hemispheres may result from impact of the leading face of the snow crystal with cloud droplets. The elongated and sinuous configurations of frozen cloud droplets that are encountered on the more advanced stages suggest that aerodynamic forces propel cloud droplets to the trailing face of the descending crystal where they make contact and freeze. C1 USDA ARS, Soybean Genom & Improvement Lab, Beltsville, MD 20705 USA. New Mexico State Univ, USDA ARS, Las Cruces, NM 88003 USA. NASA, Goddard Space Flight Ctr, Lab Hydrol Sci, Greenbelt, MD 20771 USA. US Geol Survey, Washington Water Sci Ctr, Tacoma, WA USA. USDA ARS, Hydrol & Remote Sensing Lab, Beltsville, MD USA. RP Wergin, WP (reprint author), USDA ARS, Soybean Genom & Improvement Lab, Beltsville, MD 20705 USA. NR 32 TC 8 Z9 8 U1 1 U2 7 PU FAMS INC PI MAHWAH PA BOX 832, MAHWAH, NJ 07430-0832 USA SN 0161-0457 J9 SCANNING JI Scanning PD MAY-JUN PY 2003 VL 25 IS 3 BP 121 EP 131 PG 11 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA 694WW UT WOS:000183799000003 PM 12866645 ER PT J AU Murray, SL Newman, FD Murray, CS Wilt, DM Wanlass, MW Ahrenkiel, P Messham, R Siergiej, RR AF Murray, SL Newman, FD Murray, CS Wilt, DM Wanlass, MW Ahrenkiel, P Messham, R Siergiej, RR TI MOCVD growth of lattice-matched and mismatched InGaAs materials for thermophotovoltaic energy conversion SO SEMICONDUCTOR SCIENCE AND TECHNOLOGY LA English DT Article AB The details of MOCVD growth of lattice-matched (0.74 eV) and lattice-mismatched (0.55 eV and 0.6 eV) InGaAs-based thermophotovoltaic (TPV) devices on InP substrates are discussed. The optimization of growth conditions, structural parameters and run-to-run consistency have played a key role in the development of high quality TPV devices, particularly in the development of lattice-mismatched materials. C1 Emcore Photovolta, Albuquerque, NM USA. NASA Glenn Res Ctr, Cleveland, OH USA. NREL, Golden, CO USA. Bechtel Bettis Inc, Pittsburgh, PA USA. RP Murray, SL (reprint author), Emcore Photovolta, Albuquerque, NM USA. NR 18 TC 24 Z9 27 U1 0 U2 7 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0268-1242 J9 SEMICOND SCI TECH JI Semicond. Sci. Technol. PD MAY PY 2003 VL 18 IS 5 BP S202 EP S208 AR PII S0268-1242(03)58904-0 DI 10.1088/0268-1242/18/5/309 PG 7 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Condensed Matter SC Engineering; Materials Science; Physics GA 683QK UT WOS:000183160500010 ER PT J AU Wilt, D Wehrer, R Palmisiano, M Wanlass, M Murray, C AF Wilt, D Wehrer, R Palmisiano, M Wanlass, M Murray, C TI Monolithic interconnected modules (MIMs) for thermophotovoltaic energy conversion SO SEMICONDUCTOR SCIENCE AND TECHNOLOGY LA English DT Article AB Monolithic interconnected modules (MIMs) are under development for thermophotovoltaic (TPV) energy conversion applications. MIM devices are typified by series-interconnected photovoltaic cells on a common, semi-insulating substrate and generally include rear-surface infrared (IR) reflectors. The MIM architecture is being implemented in InGaAsSb materials without semi-insulating substrates through the development of alternative isolation methodologies. Motivations for developing the MIM structure include: reduced resistive losses, higher output power density than for systems utilizing front surface spectral control, improved thermal coupling and ultimately higher system efficiency. Numerous design and material changes have been investigated since the introduction of the MIM concept in 1994. These developments as well as the current design strategies are addressed. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Bechtel Bettis Inc, W Mifflin, PA USA. NREL, Golden, CO USA. Emcore Photovolta, Albuquerque, NM USA. RP Wilt, D (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 25 TC 25 Z9 25 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0268-1242 J9 SEMICOND SCI TECH JI Semicond. Sci. Technol. PD MAY PY 2003 VL 18 IS 5 BP S209 EP S215 AR PII S0268-1242(03)60134-3 DI 10.1088/0268-1242/18/5/310 PG 7 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Condensed Matter SC Engineering; Materials Science; Physics GA 683QK UT WOS:000183160500011 ER PT J AU Torsti, J Kocharov, L Laivola, J Chertok, I Thompson, BJ AF Torsti, J Kocharov, L Laivola, J Chertok, I Thompson, BJ TI High-energy He-3-rich solar particle events SO SOLAR PHYSICS LA English DT Article ID CORONAL MASS EJECTIONS; MARCH 1991; FLARES; ACCELERATION; HE-3; SOHO; ABUNDANCES; ELECTRONS; NUCLEON; MISSION AB Energetic particle observations of the ERNE instrument on board SOHO enable measurements of He-3 and He-4 fluxes beyond 15 MeV nucleon(-1) with good statistical resolution. We report results of a survey of the ERNE observations covering the period from 8 February 1999 to 6 December 2000. We find 10 and 5 days during which the He-3-to-He-4 ratio exceeds the levels of 20% and 50%, respectively. Those periods include, in particular, four He-3-rich events that are sufficiently strong for a reasonably accurate estimate of the time-intensity profiles. We analyze the history of solar and interplanetary phenomena associated with these high-energy He-3-rich events. Basic properties of such events and significant solar and interplanetary factors are formulated. The significant factors comprise, in particular, a strong, impulsive flare, typically observed about 2/3 day before the He-3 onset, and an interplanetary shock wave or magnetic field enhancement arriving at 1 AU about 4/3 day after the He-3 onset. The high-energy He-3-rich events make up a new kind of hybrid events, possessing the impulsive-type composition and the gradual-type time-profiles. We emphasize a dependence of the resultant particle event on the history of the particular solar eruption comprising coronal mass ejection (CME) and the flare associated with the CME. C1 Univ Turku, Dept Phys, FIN-20014 Turku, Finland. Univ Turku, Vaisala Inst Space Phys & Astron, FIN-20014 Turku, Finland. IZMIRAN, Troitsk 142190, Moscow Region, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Torsti, J (reprint author), Univ Turku, Dept Phys, FIN-20014 Turku, Finland. RI Thompson, Barbara/C-9429-2012 NR 41 TC 4 Z9 4 U1 0 U2 1 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 2003 VL 214 IS 1 BP 177 EP 193 DI 10.1023/A:1024091002078 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 686MG UT WOS:000183325100011 ER PT J AU Davis, LM AF Davis, LM TI Unspun: Key concepts for understanding the World Wide Web SO TECHNICAL COMMUNICATION LA English DT Book Review C1 NASA, Jet Propuls Lab, IT Serv, Washington, DC 20546 USA. RP Davis, LM (reprint author), NASA, Jet Propuls Lab, IT Serv, Washington, DC 20546 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU SOC TECHNICAL COMMUNICATION PI ARLINGTON PA 901 NORTH STUART ST, STE 904, ARLINGTON, VA 22203 USA SN 0049-3155 J9 TECH COMMUN JI Tech. Commun. PD MAY PY 2003 VL 50 IS 2 BP 278 EP 280 PG 3 WC Communication SC Communication GA 679ZH UT WOS:000182951500029 ER PT J AU Hollingsworth, JA Banger, KK Jin, MHC Harris, JD Cowen, JE Bohannan, EW Switzer, JA Buhro, W Hepp, AF AF Hollingsworth, JA Banger, KK Jin, MHC Harris, JD Cowen, JE Bohannan, EW Switzer, JA Buhro, W Hepp, AF TI Single source precursors for fabrication of I-III-VI2 thin-film solar cells via spray CVD SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT Spring Meeting of the European-Materials-Research-Society (E-MRS) CY JUN 18-21, 2002 CL STRASBOURG, FRANCE SP European Mat Res Soc DE chemical vapour deposition; chalcopyrite; thin-film technology; solar cells ID MICROSTRUCTURE; SEMICONDUCTORS; CUGAS2 AB The development of thin-film solar cells on flexible, lightweight, space-qualified substrates provides an attractive cost solution to fabricating solar arrays with high specific power (W/kg). Thin-film fabrication studies demonstrate that ternary single source precursors can be used in either a hot, or cold-wall spray chemical vapour deposition reactor, for depositing CuInS2, CuGaS2 and CuGaInS2 at reduced temperatures (400-450 degreesC), which display good electrical and optical properties suitable for photovoltaic devices. X-ray diffraction studies, energy dispersive spectroscopy and scanning electron microscopy confirmed the formation of the single phase CIS, CGS, CIGS thin-films on various substrates at reduced temperatures. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, Glenn Res Ctr, Photovolta & Space Environm Branch, Cleveland, OH 44135 USA. Washington Univ, Dept Chem, St Louis, MO 63130 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. Cleveland State Univ, Dept Chem, Cleveland, OH 44115 USA. Univ Missouri, Dept Chem, Rolla, MO 65409 USA. RP Buhro, W (reprint author), NASA, Glenn Res Ctr, Photovolta & Space Environm Branch, 21000 Brookpk Rd,Mail Stop 302-1, Cleveland, OH 44135 USA. NR 22 TC 61 Z9 63 U1 4 U2 21 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD MAY 1 PY 2003 VL 431 BP 63 EP 67 DI 10.1016/S0040-6090(03)00196-2 PG 5 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 692VG UT WOS:000183680500014 ER PT J AU Wong, AS Yung, YL Friedson, AJ AF Wong, AS Yung, YL Friedson, AJ TI Benzene and haze formation in the polar atmosphere of Jupiter SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID HYDROCARBON IONS; CHEMISTRY; IONOSPHERE; PHOTOCHEMISTRY; H-2 AB [1] Jupiter has a large magnetosphere that episodically precipitates large amounts of energy into the polar atmosphere, giving rise to intense auroras [Clarke et al., 1996; Grodent et al., 2000]. An important consequence of this energy influx is the production of a dark haze [Pryor and Hord, 1991], the formation mechanism of which was hitherto poorly known. Recent observations of benzene on Jupiter [Bezard et al., 2001; Flasar, 2002] provide new clues for a chemical and aerosol model for the formation of heavy hydrocarbon aerosols. The chemistry begins with the destruction of methane by energetic particles, followed by neutral and ion reactions, ultimately leading to the formation of benzene and other complex hydrocarbons, including multi-ring compounds which subsequently condense. High temperatures and effective eddy mixing engendered by the auroras enhance the formation of heavy hydrocarbons and aerosols. This mechanism may be relevant in the atmospheres of Saturn and extrasolar giant planets, and is an example of how a planetary magnetosphere may influence the chemical composition and climate forcing of the upper atmosphere. C1 Univ Michigan, Ann Arbor, MI 48104 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. RP Wong, AS (reprint author), Univ Michigan, Ann Arbor, MI 48104 USA. NR 29 TC 41 Z9 41 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 APR 30 PY 2003 VL 30 IS 8 AR 1447 DI 10.1029/2002GL016661 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 678GH UT WOS:000182857800001 ER PT J AU Michalsky, J Min, Q Barnard, J Marchand, R Pilewskie, P AF Michalsky, J Min, Q Barnard, J Marchand, R Pilewskie, P TI Simultaneous spectral albedo measurements near the Atmospheric Radiation Measurement Southern Great Plains (ARM SGP) central facility SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE spectral albedo; downwelling spectral and broadband diffuse irradiance models; aircraft and ground-based spectral albedo comparisons; inhomogeneous spectral albedo AB [1] During the second Atmospheric Radiation Measurement ( ARM) Enhanced Shortwave Experiment (ARESE II), measurements were obtained during low-altitude passes of the Twin Otter aircraft directly over the central facility of the ARM Southern Great Plains (SGP) site. One set of measurements taken from this platform was the spectral irradiance pointing in the nadir and in the zenith with moderate spectral resolution from about 350 to 1670 nm using the NASA Ames solar spectral flux radiometer (SSFR). Routine measurements are made at the central facility (CF) of the ARM SGP site using two multifilter radiometer (MFR) heads with six narrowband filters covering portions of the spectrum between 415 and 940 nm. One measures upwelling spectral irradiance above an ungrazed pasture, and the other measures that above a wheat field. In addition, on one of the cloudy days during ARESE II ( 3 March 2000), measurements were made with a hand-held, commercial spectrometer above wheat, pasture, and dry corn stalks in and around the CF site between the wavelengths of 350 and 2340 nm. A needed input to radiation modeling at the top of the atmosphere and at the surface is the effective spectral surface albedo. In the calculation of downwelling radiation at the surface it is important to correctly specify surface albedo in overcast and clear conditions. This paper will examine the level of agreement among different spectral albedo measurements. The effect of the differences on calculated downwelling surface irradiance will be analyzed for thin and heavy overcast. Finally, the importance of spectral albedo versus a single-valued broadband albedo on modeled, clear-sky diffuse irradiance is demonstrated. C1 SUNY Albany, Atmospher Sci Res Ctr, Albany, NY USA. Pacific NW Natl Lab, Richland, WA 99352 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Michalsky, J (reprint author), SUNY Albany, Atmospher Sci Res Ctr, 251 Fuller Rd, Albany, NY USA. EM joe@asrc.cestm.albany.edu; min@asrc.cestm.albany.edu; james.barnard@pnl.gov; roger.marchand@pnl.gov; ppilewskie@mail.arc.nasa.gov NR 5 TC 23 Z9 23 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 30 PY 2003 VL 108 IS D8 AR 4254 DI 10.1029/2002JD002906 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 678HJ UT WOS:000182860800002 ER PT J AU Bougamont, M Tulaczyk, S Joughin, I AF Bougamont, M Tulaczyk, S Joughin, I TI Response of subglacial sediments to basal freeze-on - 2. Application in numerical modeling of the recent stoppage of Ice Stream C, West Antarctica SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Review DE ice stream; ice dynamics; till; stoppage; ice modeling ID SEA-LEVEL RISE; PLEISTOCENE-HOLOCENE RETREAT; SURFACE MASS-BALANCE; SHEET COLLAPSE; FORCE BUDGET; ROSS SEA; MARGIN MIGRATION; WATER-PIRACY; SIPLE DOME; BENEATH AB [1] Ross ice streams supply over 90% of the ice volume flowing out of the Ross sector of the West Antarctic ice sheet (WAIS). Stoppage of Ice Stream C (ISC) ca. 150 years ago appears to have pushed this sector of WAIS from negative into positive mass balance [Joughin and Tulaczyk, 2002]. We propose an explanation for the unsteady behavior of ISC using a new numerical ice-stream model, which includes an explicit treatment of a subglacial till layer. When constrained by initial conditions emulating prestoppage geometry, dynamics, and mass balance of ISC, the model yields a rapid (similar to100 years) stoppage of the main ice-stream trunk. The stoppage is triggered by basal freeze-on, which consolidates and strengthens the subglacial till. Our numerical simulations produce results consistent with a number of existing observations, for example, continuing activity of the two tributaries of ISC. The model always yields rapid stoppage unless we specify ice-stream width that is smaller than its prestoppage values (maximum of similar to80 km). We conjecture that if ISC was active for at least a few thousand years before slowdown, its width was significantly smaller than today to sustain the long active phase. Ice-stream width is a key control that helps determine whether ice-stream flow is sustainable over a long term. Our work indicates that the recent stoppage of Ice Stream C could have been part of inherent ice-stream cyclicity, and it leaves open the possibility that other active ice streams may evolve in the future toward rapid shutdowns. C1 Univ Calif Santa Cruz, Dept Earth Sci, Santa Cruz, CA 95064 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bougamont, M (reprint author), Univ Calif Santa Cruz, Dept Earth Sci, Earth & Marine Sci Bldg, Santa Cruz, CA 95064 USA. EM tulaczyk@es.ucsc.edu; ian@radar-sci.jpl.nasa.gov RI Joughin, Ian/A-2998-2008 OI Joughin, Ian/0000-0001-6229-679X NR 100 TC 44 Z9 44 U1 0 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD APR 30 PY 2003 VL 108 IS B4 AR 2223 DI 10.1029/2002JB001936 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 678JK UT WOS:000182863600002 ER PT J AU Zhou, XY Strangeway, RJ Anderson, PC Sibeck, DG Tsurutani, BT Haerendel, G Frey, HU Arballo, JK AF Zhou, XY Strangeway, RJ Anderson, PC Sibeck, DG Tsurutani, BT Haerendel, G Frey, HU Arballo, JK TI Shock aurora: FAST and DMSP observations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE solar wind-magnetosphere-ionosphere interaction; auroras; particle precipitation ID INTERPLANETARY MAGNETIC-FIELD; KELVIN-HELMHOLTZ INSTABILITY; PLASMA-WAVE TURBULENCE; WIND DYNAMIC PRESSURE; CAP BOUNDARY-LAYER; SOLAR-WIND; POLAR-CAP; B-Y; MAGNETOSPHERIC RESPONSE; SUDDEN-COMMENCEMENT AB [1] Global signatures of the aurora caused by interplanetary shocks/pressure pulses have been studied in recent years using ultraviolet imager data from polar orbiting spacecraft. The signatures include the occurrence of the aurora first near local noon and then propagation antisunward along the auroral oval at very high speeds. To better understand the mechanisms of particle precipitation, in this paper we study shock auroras using near-Earth observations of the FAST and DMSP satellites. We have studied the events that occurred during 1996-2000 where FAST and/or DMSP crossed the dawnside or duskside auroral zone within 10 min after shocks/pressure pulses arrived at the nose of the magnetopause. It is found that the electron precipitation increased significantly above the dawnside and duskside auroral oval zone after the shock/pressure pulse arrivals. The precipitation structure is low-energy electrons (5 Dobson units (DU)) when the anomalies above 20 hPa and from 50 to 20 hPa reinforce. There were four such cases at 20degreesN and at 20degreesS in 1985-1991, but five at 20degreesN and only one at 20degreesS in 1993-1999. About 70% of these cases are associated with strong shear at 25-35 hPa in late fall/early winter. There is a weak subtropical anomaly in column ozone when the ozone anomalies above and below 20 hPa are of opposite sign, or one of them is very weak. Over half of these cases are associated with strong wind shear in late fall/early winter in the middle stratosphere at 12.5 hPa. In the southern subtropics, there is strong shear at 12.5 hPa and a weak column ozone anomaly for 5 of 6 years from 1994 to 1999. Near 20degreesN the seasonal cycle contributes more to the ozone variance above 20 hPa than does the QBO, but the reverse appears true near 20degreesS. The seasonal cycle dominates the variance in ozone below 40 hPa at 20degreesS. The effects of ENSO are more important for ozone than those of the QBO below 60 hPa at 20degreesN. C1 Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. NOAA, Climate & Diagnost Lab, Boulder, CO 80303 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Kenya Meteorol Dept, Nairobi, Kenya. NASA, Observat Sci Branch, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Logan, JA (reprint author), Harvard Univ, Dept Earth & Planetary Sci, 29 Oxford St, Cambridge, MA 02138 USA. EM jal@io.harvard.edu RI Randel, William/K-3267-2016; Jones, Dylan/O-2475-2014 OI Randel, William/0000-0002-5999-7162; Jones, Dylan/0000-0002-1935-3725 NR 43 TC 38 Z9 39 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 23 PY 2003 VL 108 IS D8 AR 4244 DI 10.1029/2002JD002170 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 678AK UT WOS:000182842400001 ER PT J AU Weaver, CJ Joiner, J Ginoux, P AF Weaver, CJ Joiner, J Ginoux, P TI Mineral aerosol contamination of TIROS Operational Vertical Sounder (TOVS) temperature and moisture retrievals SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE TOVS; dust; mineral; aerosol; temperature; retrievals ID SEA-SURFACE TEMPERATURE; GOCART MODEL; SAHARAN DUST; SYSTEM; UV AB Since mineral aerosols absorb significant amounts of infrared radiation, they may contribute to errors in the retrievals of atmospheric and surface parameters from the TIROS Operational Vertical Sounder (TOVS) High-Resolution Infrared Radiation Sounder (HIRS) if the atmosphere is assumed clear. TOVS is an operational sounder on NOAA polar satellites. To see if observed brightness temperatures are reduced by mineral aerosol, we analyzed results from the Data Assimilation Office (DAO) Finite Volume Data Assimilation System (fvDAS). Every 6 hours the assimilated temperature and moisture profiles are used as a first guess in the DAO interactive cloud-clearing TOVS retrieval system. The observed minus the forecast (O-F) brightness temperature, which is a measure of the accuracy of the first guess and radiative transfer parameters, becomes more negative with increasing dust concentrations. Dust concentrations are from the Goddard Ozone Chemistry Aerosol Radiation Transport (GOCART) model. Since there was no account of dust during this fvDAS run, the dependence of O-F on the estimated atmospheric dust concentrations from GOCART indicates that the dust is affecting the TOVS brightness temperatures. HIRS channels that are sensitive to the surface temperature, lower tropospheric temperature, and moisture are subject to a 0.5 K or more reduction in the brightness temperature during heavy dust loading conditions. The radiative transfer module used in the TOVS retrieval system was modified to account for dust assuming a composition of illite, and the fvDAS run was repeated. Accounting for dust absorption in the retrieval system yields warmer surface temperatures (0.4 K) and warmer lower tropospheric temperatures in regions of moderate dust loading over the tropical Atlantic. C1 Univ Maryland Baltimore Cty, GEST, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. RP Weaver, CJ (reprint author), Univ Maryland Baltimore Cty, GEST, NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA. EM weaver@demeter.gsfc.nasa.gov; joiner@dao.gsfx.nasa.gov; ginoux@rondo.gsfc.nasa.gov RI Joiner, Joanna/D-6264-2012; Ginoux, Paul/C-2326-2008 OI Ginoux, Paul/0000-0003-3642-2988 NR 23 TC 7 Z9 7 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 23 PY 2003 VL 108 IS D8 AR 4246 DI 10.1029/2002JD002571 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 678AK UT WOS:000182842400002 ER PT J AU Anjali, T Scoglio, C Uhl, G AF Anjali, T Scoglio, C Uhl, G TI A new scheme for traffic estimation and resource allocation for bandwidth brokers SO COMPUTER NETWORKS LA English DT Article DE bandwidth broker; resource allocation; resource provisioning; capacity reservation; traffic estimation; bandwidth usage ID VBR VIDEO AB This paper is motivated by the concern of a multi-service network provider who plans to offer quality of service guarantees to users. A bandwidth broker acts as the resource manager for each network provider. Neighboring bandwidth brokers communicate with each other to establish inter-domain resource reservation agreements. Conventional approaches for resource allocation rely on pre-determined traffic characteristics. If allocation follows the traffic demand very tightly, the resource usage is efficient but leads to frequent modifications of the reservations. This would lead to increased inter-bandwidth-broker signaling in order to propagate the changes to all the concerned networks. Contrarily, if large cushions are allowed in the reservations, the modifications are far spaced in time but the resource usage becomes highly inefficient. In this paper, a new scheme for estimating the traffic on an inter-domain link and forecasting its capacity requirement, based on a measurement of the current usage, is proposed. The method allows an efficient resource utilization while keeping the number of reservation modifications to low values. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Georgia Inst Technol, Sch Elect & Comp Engn, Broadband & Wireless Networking Lab, Atlanta, GA 30332 USA. Swales Aerosp, Beltsville, MD 20705 USA. NASA Goddard, Beltsville, MD 20705 USA. RP Georgia Inst Technol, Sch Elect & Comp Engn, Broadband & Wireless Networking Lab, Atlanta, GA 30332 USA. EM tricha@ece.gatech.edu; caterina@ece.gatech.edu; uhl@rattler.gsfc.nasa.gov NR 24 TC 12 Z9 12 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1389-1286 EI 1872-7069 J9 COMPUT NETW JI Comput. Netw. PD APR 22 PY 2003 VL 41 IS 6 BP 761 EP 777 DI 10.1016/S1389-1286(02)00438-3 PG 17 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 659PZ UT WOS:000181787100005 ER PT J AU Steele, HM Eldering, A Sen, B Toon, GC Mills, FP Kahn, BH AF Steele, HM Eldering, A Sen, B Toon, GC Mills, FP Kahn, BH TI Retrieval of stratospheric aerosol size and composition information from solar infrared transmission spectra SO APPLIED OPTICS LA English DT Article; Proceedings Paper CT 8th Topical Meeting on Laser Applications to Chemical and Environmental Analysis (8th LACEA) CY FEB 07-10, 2002 CL BOULDER, CO SP Opt Soc Amer ID HALOGEN OCCULTATION EXPERIMENT; PINATUBO VOLCANIC AEROSOL; SAGE-II; EXTINCTION MEASUREMENTS; SURFACE-AREA; INVERSION ALGORITHM; REFRACTIVE-INDEX; POLAR OZONE; POAM II; ABSORPTION-SPECTRA AB Infrared transmission spectra were recorded by the Jet Propulsion Laboratory MkIV interferometer during flights aboard the NASA DC-8 aircraft as part of the Airborne Arctic Stratospheric Expedition II (AASE II) mission in the early months of 1992. In our research, we infer the properties of the stratospheric aerosols from these spectra. The MkIV instrument employs two different detectors, a HgCdTe photoconductor for 650-1850 cm(-1) and an InSb photodiode for 1850-5650 cm(-1), to simultaneously record the solar intensity throughout the mid-infrared. These spectra have been used. to retrieve the concentrations of a large number of gases, including chlorofluorocarbons, NOy species, O-3, and ozone-depleting gases. We demonstrate how the residual continua spectra, obtained after accounting for the absorbing gases, can be used to obtain information about the stratospheric aerosols. Infrared extinction spectra are calculated for a range of modeled aerosol size distributions and compositions with Mie theory and fitted to the measured residual spectra. By varying the size distribution parameters and sulfate weight percent, we obtain the microphysical properties of the aerosols that best fit the observations. The effective radius of the aerosols is found to be between 0.4 and 0.6 mum, consistent with that derived from a large number of instruments in this post-Pinatubo period. We demonstrate how different parts of the spectral range can be used to constrain the range of possible values of this size parameter and show how the broad spectral bandpass of the MkIV instrument presents a great advantage for retrieval of both aerosol size and composition over instruments with a more limited spectral range. The aerosol composition that provides the best fit to the measured spectra is a 70-75% sulfuric acid solution, in good agreement with that obtained from thermodynamic considerations. (C) 2003 Optical Society of America. C1 Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90095 USA. Calif State Univ Northridge, Dept Geog, Northridge, CA 91330 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Steele, HM (reprint author), Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90095 USA. EM cox@atmos.ucla.edu NR 60 TC 6 Z9 7 U1 1 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD APR 20 PY 2003 VL 42 IS 12 BP 2140 EP 2154 DI 10.1364/AO.42.002140 PG 15 WC Optics SC Optics GA 670BD UT WOS:000182386600016 PM 12716156 ER PT J AU Mennella, V Baratta, GA Esposito, A Ferini, G Pendleton, YJ AF Mennella, V Baratta, GA Esposito, A Ferini, G Pendleton, YJ TI The effects of ion irradiation on the evolution of the carrier of the 3.4 micron interstellar absorption band SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; cosmic rays; dust, extinction; infrared : ISM ID AMORPHOUS-CARBON FILMS; MU-M FEATURE; H2O ICE BANDS; LINE-OF-SIGHT; GALACTIC-CENTER; C-H; INFRARED-SPECTROSCOPY; ASTROPHYSICAL INTEREST; UV PHOTODESTRUCTION; OPTICAL-PROPERTIES AB Carbon grains in the interstellar medium evolve through exposure to UV photons, heat, gas, and cosmic rays. Understanding their formation, evolution, and destruction is an essential component of evaluating the composition of the dust available for newly forming planetary systems. The 3.4 mum absorption band, attributed to the aliphatic C-H stretch vibration, is a useful probe of the degree to which energetic processing affects hydrogenated carbon grains. Here we report on the effects of ion bombardment of two different kinds of nano-size hydrogenated carbon grains with different hydrogen content. Grain samples, both with and without a mantle of H(2)O ice, were irradiated with 30 keV He(+) to simulate cosmic-ray processing in both diffuse and dense interstellar medium conditions. The ion fluences ranged between 1.5 x 10(13) and 7.9 x 10(15) ions cm(-2). Infrared and Raman spectroscopy were used to study the effects of ion irradiation on grains. In both the dense and diffuse interstellar medium simulations, ion bombardment led to a reduction of the 3.4 mum band intensity. To discuss the effects of cosmic-ray irradiation of interstellar hydrogenated carbon materials we adopt the approximation of 1 MeV monoenergetic protons. An estimate of the C-H bond destruction cross section by 1 MeV protons was made based on experiments using 30 keV He(+) ions and model calculations. In combination with results from our previous studies, which focused on UV irradiation and thermal H atom bombardment, the present results indicate that the C-H bond destruction by fast-colliding charged particles is negligible with respect to that of UV photons in the diffuse ISM. However, in dense cloud regions, cosmic-ray bombardment is the most significant C-H bond destruction mechanism when the optical depth corresponds to values of the visual extinction larger than similar to5 mag. The results presented here strengthen the new interpretation of the evolution of the interstellar aliphatic component (i.e., the C-H bonds in the CH(2) and CH(3) groups) as evidenced by the presence of the 3.4 mum absorption band in the diffuse medium and the absence of such a signature in the dense cloud environment. The evolutionary transformation of carbon grains, induced by H atoms, UV photons, and cosmic rays, indicates that C-H bonds are readily formed, in situ, in the diffuse interstellar medium and are destroyed in the dense cloud environment. C1 Osserv Astron Capodimonte, Ist Nazl Astrofis, I-80131 Naples, Italy. Osserv Astrofis Catania, Ist Nazl Astrofis, I-95123 Catania, Italy. Univ Studi Napoli Parthenope, I-80133 Naples, Italy. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Mennella, V (reprint author), Osserv Astron Capodimonte, Ist Nazl Astrofis, Via Moiariello 16, I-80131 Naples, Italy. NR 77 TC 78 Z9 78 U1 0 U2 7 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 2003 VL 587 IS 2 BP 727 EP 738 DI 10.1086/368342 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 666CR UT WOS:000182159400024 ER PT J AU Lenters, GT Woods, PM Goupell, JE Kouveliotou, C Gogus, E Hurley, K Frederiks, D Golenetskii, S Swank, J AF Lenters, GT Woods, PM Goupell, JE Kouveliotou, C Gogus, E Hurley, K Frederiks, D Golenetskii, S Swank, J TI An extended burst tail from SGR 1900+14 with a thermal X-ray spectrum SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : individual (SGR 1900+14); stars : neutron; X-rays : bursts ID GAMMA-REPEATER SGR-1900+14; MAGNETIZED NEUTRON-STARS; VARIABLE SPIN-DOWN; AUGUST 27; EMISSION; BEPPOSAX; SGR-1806-20; DISCOVERY; MAGNETARS; OUTBURST AB The soft gamma repeater SGR 1900+14 entered a new phase of activity in 2001 April initiated by the intermediate. are recorded on April 18. Ten days following this. are, we discovered an abrupt increase in the source flux between consecutive Rossi X-Ray Timing Explorer (RXTE) orbits. This X-ray flux excess decayed over the next several minutes and was subsequently linked to a high fluence burst from SGR 1900+14 recorded by other spacecraft (Ulysses and Wind/Konus) while the SGR was Earth-occulted for RXTE. We present here spectral and temporal analysis of both the burst of April 28 and the long X-ray tail following it. We find strong evidence of an exclusively thermal X-ray tail in this event and bring this evidence to bear on other bursts and flares from SGR 1900+14 that have shown extended X-ray excesses (e.g., 1998 August 29). We include in this comparison a discussion of the physical origins of SGR bursts and extended X-ray tails. C1 Calvin Coll, Dept Phys & Astron, Grand Rapids, MI 49546 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Hope Coll, Dept Phys & Engn, Holland, MI 49422 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Calvin Coll, Dept Phys & Astron, Grand Rapids, MI 49546 USA. RI Swank, Jean/F-2693-2012; Frederiks, Dmitry/C-7612-2014; Golenetskii, Sergey/B-3818-2015; OI Frederiks, Dmitry/0000-0002-1153-6340 NR 34 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 APR 20 PY 2003 VL 587 IS 2 BP 761 EP 770 DI 10.1086/368343 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 666CR UT WOS:000182159400027 ER PT J AU McAteer, RTJ Gallagher, PT Williams, DR Mathioudakis, M Bloomfield, DS Phillips, KJH Keenan, FP AF McAteer, RTJ Gallagher, PT Williams, DR Mathioudakis, M Bloomfield, DS Phillips, KJH Keenan, FP TI Observational evidence for mode coupling in the chromospheric network SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; Sun : chromosphere; Sun : magnetic fields; Sun : oscillations; Sun : photosphere ID MAGNETIC-FLUX TUBES; LONGITUDINAL-TRANSVERSE WAVES; SOLAR CHROMOSPHERE; BRIGHT POINTS; OSCILLATIONS; ATMOSPHERE; SUN; PROPAGATION; CORONA; QUIET AB Oscillations in network bright points (NBPs) are studied at a variety of chromospheric heights. In particular, the three-dimensional variation of NBP oscillations is studied using image segmentation and cross-correlation analysis between images taken in light of Ca II K-3, Halpha core, Mg I b(2), and Mg I b(1) - 0.4 Angstrom. Wavelet analysis is used to isolate wave packets in time and to search for height-dependent time delays that result from upward- or downward-directed traveling waves. In each NBP studied, we find evidence for kink-mode waves (1.3, 1.9 mHz), traveling up through the chromosphere and coupling with sausage-mode waves (2.6, 3.8 mHz). This provides a means for depositing energy in the upper chromosphere. We also find evidence for other upward- and downward-propagating waves in the 1.3-4.6 mHz range. Some oscillations do not correspond to traveling waves, and we attribute these to waves generated in neighboring regions. C1 Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. NASA, Goddard Space Flight Ctr, L3 Commun EER Syst Inc, Greenbelt, MD 20771 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. RP Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. RI McAteer, R. T. James/D-3736-2011; Williams, David/E-6676-2011; Bloomfield, Shaun/G-5809-2011; Gallagher, Peter/C-7717-2011 OI Williams, David/0000-0001-9922-8117; Bloomfield, Shaun/0000-0002-4183-9895; Gallagher, Peter/0000-0001-9745-0400 NR 36 TC 44 Z9 44 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 20 PY 2003 VL 587 IS 2 BP 806 EP 817 DI 10.1086/368304 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 666CR UT WOS:000182159400032 ER PT J AU Ichoku, C Kaufman, YJ Giglio, L Li, Z Fraser, RH Jin, JZ Park, WM AF Ichoku, C Kaufman, YJ Giglio, L Li, Z Fraser, RH Jin, JZ Park, WM TI Comparative analysis of daytime fire detection algorithms using AVHRR data for the 1995 fire season in Canada: perspective for MODIS SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article; Proceedings Paper CT 3rd International Workshop on Remote Sensing and GIS Application to Forest Fire Management CY MAY, 2001 CL PARIS, FRANCE SP European Assoc Remote Sensing Lab, Special Interest Grp Forest Fire ID HIGH-RESOLUTION RADIOMETER; BOREAL FOREST-FIRES; CONTEXTUAL ALGORITHM; WEST-AFRICA; CALIBRATION; CHANNELS AB Two fixed-threshold (CCRS and ESA) and three contextual (GIGLIO, IGBP, and MODIS) algorithms were used for fire detection with Advanced Very High Resolution Radiometer (AVHRR) data acquired over Canada during the 1995 fire season. The CCRS algorithm was developed for the boreal ecosystem, while the other four are for global application. The MODIS algorithm, although developed specifically for use with the MODIS sensor data, was applied to AVHRR in this study for comparative purposes. Fire detection accuracy assessment for the algorithms was based on comparisons with available 1995 burned area ground survey maps covering five Canadian provinces. Overall accuracy estimations in terms of omission (CCRS=46%, ESA=81%, GIGLIO=75%, IGBP=51%, MODIS=81%) and commission (CCRS=0.35%, ESA=0.08%, GIGLIO=0.56%, IGBP=0.75%, MODIS=0.08%) errors over forested areas revealed large differences in performance between the algorithms, with no relevance to type (fixed-threshold or contextual). CCRS performed best in detecting real forest fires, with the least omission error, while ESA and MODIS produced the highest omission error, probably because of their relatively high threshold values designed for global application. The commission error values appear small because the area of pixels falsely identified by each algorithm was expressed as a ratio of the vast unburned forest area. More detailed study shows that most commission errors in all the algorithms were incurred in non-forest agricultural areas, especially on days with very high surface temperatures. The advantage of the high thresholds in ESA and MODIS was that they incurred the least commission errors. The poor performance of the algorithms (in terms of omission errors) is not only due to their quality but also to cloud cover, low satellite overpass frequency, and the saturation of AVHRR channel 3 at about 321 K. Great improvement in global fire detection can probably be achieved by exploring the use of a wide variety of channel combinations from the data-rich MODIS instruments. More sophisticated algorithms should be designed to accomplish this. C1 NASA, Sci Syst & Applicat Inc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Res Council Canada, Canada Ctr Remote Sensing, Ottawa, ON K1A OY7, Canada. RP Ichoku, C (reprint author), NASA, Sci Syst & Applicat Inc, Goddard Space Flight Ctr, Code 913, Greenbelt, MD 20771 USA. EM ichoku@climate.gsfc.nasa.gov RI Ichoku, Charles/E-1857-2012; Li, Zhanqing/F-4424-2010 OI Ichoku, Charles/0000-0003-3244-4549; Li, Zhanqing/0000-0001-6737-382X NR 32 TC 44 Z9 47 U1 0 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 APR 20 PY 2003 VL 24 IS 8 BP 1669 EP 1690 DI 10.1080/01431160210144697 PG 22 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 667LM UT WOS:000182233700006 ER PT J AU Kaufman, YJ Ichoku, C Giglio, L Korontzi, S Chu, DA Hao, WM Li, RR Justice, CO AF Kaufman, YJ Ichoku, C Giglio, L Korontzi, S Chu, DA Hao, WM Li, RR Justice, CO TI Fire and smoke observed from the Earth Observing System MODIS instrument - products, validation, and operational use SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article; Proceedings Paper CT 3rd International Workshop on Remote Sensing and GIS Application to Forest Fire Management CY MAY, 2001 CL PARIS, FRANCE SP European Assoc Remote Sensing Lab, Special Interest Grp Forest Fire ID BOREAL FOREST-FIRES; SCAR-B; SOUTH-AMERICA; EOS-MODIS; AEROSOL; EMISSIONS; TROPICS; RADIOMETER; PARTICLES; AIRBORNE AB The Moderate Resolution Imaging Spectrorachometer (MODIS) sensor, launched on the National Aeronautics and Space Administration Terra satellite at the end of 1999, was designed with 36 spectral channels for a wide array of land, ocean, and atmospheric investigations. MODIS has a unique ability to observe fires, smoke, and burn scars globally. Its main fire detection channels saturate at high brightness temperatures: 500 K at 4 mum and 400 K at 11 mum, which can only be attained in rare circumstances at the 1 km fire detection spatial resolution. Thus, unlike other polar orbiting satellite sensors with similar thermal and spatial resolutions, but much lower saturation temperatures (e.g. Advanced Very High Resolution Radiometer and Along Track Scanning Radiometer), MODIS can distinguish between low intensity ground surface fires and high intensity crown forest fires. Smoke column concentration over land is for the first time being derived from the MODIS solar channels, extending from 0.41 mum to 2.1 mum. The smoke product has been provisionally validated both globally and regionally over southern Africa and central and south America. Burn scars are observed from MODIS even in the presence of smoke, using the 1.2 to 2.1 mum channels. MODIS burned area information is used to estimate pyrogenic emissions. A wide range of these fire and related products and validation are demonstrated for the wild fires that occurred in northwestern USA in Summer 2000. The MODIS rapid response system and direct broadcast capability is being developed to enable users to obtain and generate data in near real-time. It is expected that health and land management organizations will use these systems for monitoring the occurrence of fires and the dispersion of smoke within two to six hours after data acquisition. C1 NASA, Goddard Space Flight Ctr, Lab Atmospheres 913, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Lab Terr Phys 923, Greenbelt, MD 20771 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. Univ Virginia, Dept Environm Sci, Charlottesville, VA 22903 USA. USDA, Rocky Mt Res Stn, Forest Serv, Missoula, MT 59807 USA. RP Kaufman, YJ (reprint author), NASA, Goddard Space Flight Ctr, Lab Atmospheres 913, Greenbelt, MD 20771 USA. EM kaufman@climate.gsfc.nasa.gov RI Ichoku, Charles/E-1857-2012 OI Ichoku, Charles/0000-0003-3244-4549 NR 42 TC 63 Z9 66 U1 2 U2 13 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 APR 20 PY 2003 VL 24 IS 8 BP 1765 EP 1781 DI 10.1080/01431160210144741 PG 17 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 667LM UT WOS:000182233700011 ER PT J AU Thornton, BF Toohey, DW Avallone, LM Harder, H Martinez, M Simpas, JB Brune, WH Avery, MA AF Thornton, BF Toohey, DW Avallone, LM Harder, H Martinez, M Simpas, JB Brune, WH Avery, MA TI In situ observations of ClO near the winter polar tropopause SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE Arctic; ozone; chlorine; bromine; tropopause; cirrus ID MIDLATITUDE OZONE LOSS; HETEROGENEOUS CHEMISTRY; LOWER STRATOSPHERE; INSITU OBSERVATIONS; CIRRUS CLOUDS; REGION; CHLORINE; PHOTOCHEMISTRY; TROPOSPHERE; INSTRUMENT AB Significant abundances of chlorine oxide (ClO) were observed throughout the lowermost stratosphere at high latitudes during winter from the NASA DC-8 aircraft during the SAGE III-Ozone Loss and Validation Experiment and Third European Stratospheric Experiment on Ozone 2000 (SOLVE/THESEO 2000) campaign. Mixing ratios of ClO averaging 15-20 parts per trillion by volume (pptv) were observed near the tropopause, a region where ClO abundances are usually only a pptv or less at lower latitudes. The ratio of ClO to inferred inorganic chlorine ([ClO]/[Cl-y]) was found to be largest (similar to7%) in air characterized by low abundances of ozone (similar to100-250 parts per billion by volume (ppbv)). This was the region where cirrus clouds were also observed occasionally during the measurement period, although abundances of ClO directly within cirrus clouds were not significantly different than background abundances. Nonzero instrument signals during darkness are attributed to detection of similar to5-15 pptv of OClO. BrO mixing ratios between 2 and 4 pptv are sufficient to produce these amounts of OClO, assuming daytime mixing ratios of ClO between 15 and 20 pptv. At these levels of ClO and BrO, approximately 10% of the ozone at these altitudes is chemically destroyed per month in springtime by reactions of ClO and BrO, representing an effective loss process for ozone near the high-latitude tropopause. C1 Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ Colorado, Program Atmospher & Ocean Sci, Boulder, CO 80309 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Avallone, LM (reprint author), Univ Colorado, Dept Chem, Campus Box 215, Boulder, CO 80309 USA. EM brett.thornton@colorado.edu; Darin.Toohey@colorado.edu; avallone@lasp.colorado.edu; harder@mpch-mainz.mpg.de; martinez@mpch-mainz.mpg.de; jbsimpas@essc.psu.edu; brune@essc.psu.edu; m.a.avery@larc.nasa.gov RI Toohey, Darin/A-4267-2008; Harder, Hartwig/L-2511-2014 OI Toohey, Darin/0000-0003-2853-1068; Harder, Hartwig/0000-0002-6868-714X NR 36 TC 17 Z9 17 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 19 PY 2003 VL 108 IS D8 AR 8333 DI 10.1029/2002JD002839 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 673RL UT WOS:000182593900001 ER PT J AU Korotaev, G Oguz, T Nikiforov, A Koblinsky, C AF Korotaev, G Oguz, T Nikiforov, A Koblinsky, C TI Seasonal, interannual, and mesoscale variability of the Black Sea upper layer circulation derived from altimeter data SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE Black Sea; circulation; sea level variation; altimeter data; data assimilation ID MODEL; SURFACE; OCEAN; ASSIMILATION; SATELLITE; LEVEL; TRANSPORT AB TOPEX/Poseidon and ERS altimeter data comprising the period from May 1992 to May 1999 are assimilated into a shallow water model for providing a dynamically consistent interpretation of the sea surface height variations and estimation of the temporal and spatial characteristics of the upper layer circulation in the Black Sea. These 7-year-long observations offer a new capability for interpretation of major transient and quasi-permanent features of the upper layer circulation. The instantaneous flow fields involve a complex, eddy-dominated system with different types of structural organizations in which the eddies and the gyres of the interior cyclonic cell interact continuously among themselves and with meanders, and filaments of the Rim Current. The circulation possesses a distinct seasonal cycle whose major characteristic features repeat every year with some year-to-year variability. An organized two-gyre winter circulation system disintegrates gradually into a series of interconnecting eddies in the summer and autumn months, which are also characterized by more pronounced and complex mesoscale activity in the peripheral flow system. Our analyses suggest a revised schematic circulation picture of the major quasi-permanent and recurrent elements of the Black Sea. C1 Natl Acad Sci Ukraine, Inst Marine Hydrophys, UA-225000 Sevastopol, Crimea, Ukraine. Middle E Tech Univ, Inst Marine Sci, TR-33731 Erdemli, Mersin, Turkey. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Korotaev, G (reprint author), Natl Acad Sci Ukraine, Inst Marine Hydrophys, 2 Kapitanskaya St, UA-225000 Sevastopol, Crimea, Ukraine. NR 33 TC 62 Z9 66 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD APR 19 PY 2003 VL 108 IS C4 AR 3122 DI 10.1029/2002JC001508 PG 16 WC Oceanography SC Oceanography GA 673RT UT WOS:000182594500001 ER PT J AU Cane, HV Richardson, IG AF Cane, HV Richardson, IG TI Interplanetary coronal mass ejections in the near-Earth solar wind during 1996-2002 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE interplanetary coronal mass ejections; coronal mass ejections; solar wind; magnetic clouds; solar cycle variation ID COSMIC-RAY DECREASES; MAGNETIC-FIELD STRUCTURE; ENERGETIC PARTICLES; GEOMAGNETIC STORMS; PROTON TEMPERATURE; SHOCK-WAVES; HEAVY-IONS; EVENTS; CLOUDS; LASCO AB [1] We summarize the occurrence of interplanetary coronal mass ejections (ICMEs) in the near-Earth solar wind during 1996 - 2002, corresponding to the increasing and maximum phases of solar cycle 23. In particular, we give a detailed list of such events. This list, based on in situ observations, is not confined to subsets of ICMEs, such as "magnetic clouds'' or those preceded by "halo'' coronal mass injections (CMEs) observed by the Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph, and provides an overview of 214 ICMEs in the near-Earth solar wind during this period. The ICME rate increases by about an order of magnitude from solar minimum to solar maximum ( when the rate is similar to3 ICMEs per solar rotation period). The rate also shows a temporary reduction during 1999 and another brief, deeper reduction in late 2000 to early 2001, which only approximately track variations in the solar 10-cm flux. In addition, there are occasional periods of several rotations duration when the ICME rate is enhanced in association with high solar activity levels. We find an indication of a periodic variation in the ICME rate, with a prominent period of similar to165 days similar to that previously reported in various solar phenomena. It is found that the fraction of ICMEs that are magnetic clouds has a solar cycle variation, the fraction being larger near solar minimum. For the subset of events that we could associate with a CME at the Sun the transit speeds from the Sun to the Earth were highest after solar maximum. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Tasmania, Sch Math & Phys, Hobart, Tas, Australia. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Cane, HV (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 661, Greenbelt, MD 20771 USA. NR 68 TC 47 Z9 47 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 18 PY 2003 VL 108 IS A4 AR 1156 DI 10.1029/2002JA009817 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 673TC UT WOS:000182595400001 ER PT J AU Jordan, CE Dibb, JE Finkel, RC AF Jordan, CE Dibb, JE Finkel, RC TI Be-10/Be-7 tracer of atmospheric transport and stratosphere-troposphere exchange SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosols; radioisotopes; beryllium; stratosphere-troposphere exchange ID INSITU MEASUREMENTS; TROPOPAUSE; OZONE; BE-7; BERYLLIUM-7; LEAD-210; OZONESONDES; LATITUDES; AEROSOLS; PACIFIC AB [1] The Be-10/Be-7 ratio is a sensitive tracer of atmospheric transport and stratosphere-troposphere exchange (STE). Data from five NASA aircraft field missions (PEM: West A and B, Tropics A; SONEX; and SUCCESS) have been assembled to produce the largest data set of Be-10, Be-7, and their ratio collected to date (> 300 samples). Ratios near 0.60 are indicative of tropospheric air with little stratospheric influence, while higher ratios are found in stratospheric air. Samples from the lower stratosphere were all collected within 2.5 km of the tropopause and had ratios >1.27. Of these lower stratosphere samples only 16% had ratios in excess of 3.0, suggesting that higher ratio air resides away from the tropopause. Seasonality observed in the Be-10/Be-7 ratios results from the downwelling of air with elevated ratios from higher in the stratosphere in the spring and summer (midlatitudes) and from the decay of Be-7 during descent in the winter polar vortex ( high latitudes). Our results illustrate the complexity of STE and some of the mechanisms through which it occurs, including tropopause folding, mixing associated with subtropical jets, and the effect of synoptic systems such as hurricanes and northeasters. The Be-10/Be-7 ratio provides important information beyond that which can be derived from studies that rely on chemical mixing ratios alone. C1 NASA, Langley Res Ctr, Natl Res Council, Hampton, VA 23681 USA. Univ New Hampshire, Climate Change Res Ctr, Durham, NH 03824 USA. Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94550 USA. RP Jordan, CE (reprint author), NASA, Langley Res Ctr, Natl Res Council, Bldg 1250,MS 483, Hampton, VA 23681 USA. EM c.e.jordan@larc.nasa.gov; Jack.Dibb@unh.edu; Finkell@lllnl.gov NR 29 TC 35 Z9 39 U1 1 U2 6 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 2003 VL 108 IS D8 AR 4234 DI 10.1029/2002JD002395 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 677ZQ UT WOS:000182840200003 ER PT J AU Nefedov, AP Morfill, GE Fortov, VE Thomas, HM Rothermel, H Hagl, T Ivlev, AV Zuzic, M Klumov, BA Lipaev, AM Molotkov, VI Petrov, OF Gidzenko, YP Krikalev, SK Shepherd, W Ivanov, AI Roth, M Binnenbruck, H Goree, JA Semenov, YP AF Nefedov, AP Morfill, GE Fortov, VE Thomas, HM Rothermel, H Hagl, T Ivlev, AV Zuzic, M Klumov, BA Lipaev, AM Molotkov, VI Petrov, OF Gidzenko, YP Krikalev, SK Shepherd, W Ivanov, AI Roth, M Binnenbruck, H Goree, JA Semenov, YP TI PKE-Nefedov: plasma crystal experiments on the International Space Station SO NEW JOURNAL OF PHYSICS LA English DT Article ID YUKAWA SYSTEMS AB The plasma crystal experiment PKE-Nefedov, the first basic science experiment on the International Space Station (ISS), was installed in February 2001 by the first permanent crew. It is designed for long-term investigations of complex plasmas under microgravity conditions. 'Complex plasmas' contain ions, electrons, neutrals and small solid particles-normally in the micrometre range. These microparticles obtain thousands of elementary charges and interact with each other via a 'screened' Coulomb potential. Complex plasmas are of special interest, because they can form liquid and crystalline states ( Thomas et al 1994 Phys. Rev. Lett. 73 652-5, Chu and I 1994 Phys. Rev. Lett. 72 4009-12) and are observable at the kinetic level. In experiments on Earth the microparticles are usually suspended against gravity in strong electric fields. This creates asymmetries, stresses and pseudo-equilibrium states with sufficient free energy to readily become unstable. Under microgravity conditions the microparticles move into the bulk of the plasma (Morfill et al 1999 Phys. Rev. Lett. 83 1598), experiencing much weaker volume forces than on Earth. This allows investigations of the thermodynamics of strongly coupled plasma states under substantially stress-free conditions. In this first paper we report our results on plasma crystals, in particular the first experimental observations of bcc lattice structures. C1 Max Planck Inst Extraterr Phys, Ctr Interdisciplinary Plasma Sci, D-85740 Garching, Germany. Russian Acad Sci, Inst High Energy Dens, Moscow 127412, Russia. Y Gagarin Cosmonauts Training Ctr, Star 141160, Moscow Region, Russia. SP Korolev RSC Energia, Korolev 141070, Moscow Region, Russia. Deutsch Zentrum Luft & Raumfahrt, D-53227 Bonn, Germany. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. NASA, Washington, DC 20546 USA. RP Morfill, GE (reprint author), Max Planck Inst Extraterr Phys, Ctr Interdisciplinary Plasma Sci, D-85740 Garching, Germany. RI Klumov, Boris/K-7735-2012; Petrov, Oleg/G-7235-2014 OI Klumov, Boris/0000-0003-4896-3925; NR 15 TC 152 Z9 154 U1 2 U2 22 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 1367-2630 J9 NEW J PHYS JI New J. Phys. PD APR 17 PY 2003 VL 5 AR 33 DI 10.1088/1367-2630/5/1/333 PG 10 WC Physics, Multidisciplinary SC Physics GA 669GG UT WOS:000182343100001 ER PT J AU Xu, XH Shi, Y Kwak, D Chang, SG Fisher, JW Pisharody, S Moran, MJ Wignarajah, K AF Xu, XH Shi, Y Kwak, D Chang, SG Fisher, JW Pisharody, S Moran, MJ Wignarajah, K TI The use of rice hulls for sustainable control of NQ(x) emissions in deep space missions SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID FLUE-GAS; ELEMENTAL SULFUR; REMOVAL; SO2; OXIDE; NOX; REDUCTION; THIOCHELATE; PHOSPHORUS; ABSORPTION AB The use of the activated carbon produced from rice hulls to control NO,, emissions for future deep space missions has been demonstrated. The optimal carbonization temperature range was found to be between 600 and 750 degreesC. A burnoff of 61.8% was found at 700 degreesC in pyrolysis and 750 degreesC in activation. The BET surface area of the activated carbon from rice hulls was determined to be 172 m(2)/g when prepared at 700 degreesC. The presence of oxygen in flue gas is essential for effective adsorption of NO by activated carbon. On the contrary, water vapor inhibits the adsorption efficiency of NO. Consequently, water vapor in flue gas should be removed by drying agents before adsorption to ensure high NO adsorption efficiency. All of the NO in the flue gas was removed for more than 1.5 h when 10% oxygen was present and the ratio of the carbon weight to the flue gas flow rate (W/F) was 15.4 g.min/L. Reduction of the adsorbed NO to form N-2 could be effectively accomplished under anaerobic conditions at 550 T. The adsorption capacity of NO on the activated carbon was found to be 5.02 mg of NO/g of carbon. The loss of carbon mass was determined to be about 0.16% of the activated carbon per cycle of regeneration if the regeneration occurred when the NO in the flue gas after the carbon bed reached 4.8 ppm, the space maximum allowable concentration. The reduction of the adsorbed NO also regenerated the activated carbon, and the regenerated activated carbon exhibited an improved NO adsorption efficiency. C1 Lawrence Berkeley Natl Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. NASA, Ames Res Ctr, Astrobiol Technol Branch, Moffett Field, CA 94035 USA. RP Chang, SG (reprint author), Lawrence Berkeley Natl Lab, Environm Energy Technol Div, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 28 TC 5 Z9 6 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD APR 16 PY 2003 VL 42 IS 8 BP 1813 EP 1820 DI 10.1021/ie020273y PG 8 WC Engineering, Chemical SC Engineering GA 667HW UT WOS:000182226500032 PM 14672085 ER PT J AU Dong, D Yunck, T Heflin, M AF Dong, D Yunck, T Heflin, M TI Origin of the international Terrestrial Reference Frame SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE origin; Terrestrial Reference Frame; GPS ID GEOCENTER VARIATIONS; PLATE MOTIONS; ROTATION; EARTH; DEFORMATION; GEODESY; SYSTEM; MODE; GPS AB [1] With recent improvements in space geodesy, the Earth's center of mass ( CM) and center of figure (CF) are no longer indistinguishable. The current origin of the International Terrestrial Reference Frame (ITRF) is defined as the CM, which shows measured seasonal variations of several millimeters to 1 cm with respect to true CM. As scientists study Earth's dynamic deformations on seasonal and shorter timescales and begin to compare observed geocenter motion with predictions from geophysical models, the reference frame origin presents significant error due to missing the geocenter motion. This paper discusses the nature of the origin of the ITRF and explores the sensitivity of GPS measurements to geocenter motion. We find that since the values of nonlinear geocenter motion are not included in the positions of the ITRF sites, the behavior of the current ITRF origin reflects CM on secular timescale but reflects CF on seasonal and short timescales. The nature of the ITRF origin depends on both the adopted kinematic model and unmodeled network motion. The realized ITRF origin should be defined by a new nomenclature to reflect its nature accurately. By the new nomenclature, the origin will maintain its current long-term stability, while improving its stability on seasonal timescales to the submillimeter level. With the degree-1 deformation approach, GPS measurements are able to provide potentially valuable information on geocenter variations on seasonal and short timescales. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dong, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Danan.Dong@jpl.nasa.gov; Thomas.P.Yunck@jpl.nasa.gov; Michael.B.Heflin@jpl.nasa.gov NR 30 TC 69 Z9 79 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD APR 16 PY 2003 VL 108 IS B4 AR 2200 DI 10.1029/2002JB002035 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 673RX UT WOS:000182594900001 ER PT J AU Beard, BL Johnson, CM Skulan, JL Nealson, KH Cox, L Sun, H AF Beard, BL Johnson, CM Skulan, JL Nealson, KH Cox, L Sun, H TI Application of Fe isotopes to tracing the geochemical and biological cycling of Fe SO CHEMICAL GEOLOGY LA English DT Article DE Fe isotopes; isotope fractionation; microbiology; banded iron formations ID PROTEROZOIC TRANSVAAL SUPERGROUP; IONIZATION MASS-SPECTROMETRY; IRON-FORMATION DEPOSITION; MANOP SITE-H; MARINE-PHYTOPLANKTON; SOUTH-AFRICA; MOSSBAUER-SPECTROSCOPY; FACIES TRANSITION; SECULAR VARIATION; FRACTIONATION AB Over 100 high-precision Fe isotope analyses of rocks and minerals are now available, which constrain the range in delta(56)Fe values (per mil deviations in Fe-56/Fe-54 ratios) in nature from -2.50parts per thousand to +1.5parts per thousand. Re-assessment of the range of delta(56)Fe values for igneous rocks, using new ultra-high-precision analytical methods discussed here, indicate that igneous Fe is isotopically homogeneous to +/-0.05parts per thousand, which represents an unparalleled baseline with which to interpret Fe isotope variations in nature. All of the isotopic variability in nature lies in fluids, rocks, and minerals that formed at low temperature. Equilibrium ("abiotic") isotopic fractionations at low temperatures may explain the range in delta(56)Fe values; experimental measurements indicate that there is a large isotopic fractionation between aqueous Fe(III) and Fe(II) (Delta(Fe(111)-Fe(11)) = 2.75parts per thousand). However, many of the natural samples that have been analyzed have an unquestionable biologic component to their genesis, and the range in delta(56)Fe values are also consistent with the experimentally measured isotopic fractionations produced by Fe-reducing bacteria. In this work, we touch on a number of aspects of Fe isotope geochemistry that bear on its application to geochemical problems in general, and biological cycling of metals in particular. We report on new state-of-the-art Fe isotope analytical, (procedures, which allow precisions of +/-0.05parts per thousand, Fe-56/Fe-54) on samples <300 ng in size. In addition, we discuss the implications of experimental work on Fe isotope fractionations during metabolic processing of Fe by bacteria and the need to take a "mechanistic" approach to understanding the pathways in which Fe isotopes may be uniquely fractionated by biology. Additionally, we discuss experimental methods, such as the use of enriched isotope tracers that are necessary to evaluate if experimental isotope exchange reactions are transient kinetic fractionations, equilibrium isotopic exchange reactions, or a combination of both, which can be caused by the complexities of multiple isotope exchange reactions taking place in an experimental system. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Univ Wisconsin, Dept Geol & Geophys, Madison, WI 53706 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Beard, BL (reprint author), Univ Wisconsin, Dept Geol & Geophys, 1215 W Dayton St, Madison, WI 53706 USA. NR 92 TC 331 Z9 358 U1 9 U2 125 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2541 J9 CHEM GEOL JI Chem. Geol. PD APR 15 PY 2003 VL 195 IS 1-4 BP 87 EP 117 DI 10.1016/S0009-2541(02)00390-X PG 31 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 666LX UT WOS:000182179700007 ER PT J AU Galeazzi, M McCammon, D AF Galeazzi, M McCammon, D TI Microcalorimeter and bolometer model SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID DOPED SILICON THERMISTORS; SUPERCONDUCTING BOLOMETERS; NOISE; CALORIMETERS; OPTIMIZATION; SENSITIVITY; DETECTORS; FEEDBACK; GE AB The standard nonequilibrium theory of noise in ideal bolometers and microcalorimeters fails to predict the performance of real devices due to additional effects that become important at low temperature. In this paper we extend the theory to include the most important of these effects and find that the performance of microcalorimeters operating at 60 mK can be quantitatively predicted. We give a simple method for doing the necessary calculations, borrowing the block diagram formalism from electronic control theory. (C) 2003 American Institute of Physics. C1 Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Galeazzi, M (reprint author), Univ Miami, Dept Phys, POB 248046, Coral Gables, FL 33124 USA. NR 20 TC 60 Z9 60 U1 0 U2 10 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 2003 VL 93 IS 8 BP 4856 EP 4869 DI 10.1063/1.1559000 PG 14 WC Physics, Applied SC Physics GA 660YL UT WOS:000181863100076 ER PT J AU Roy, S Raju, R Chuang, HF Cruden, BA Meyyappan, M AF Roy, S Raju, R Chuang, HF Cruden, BA Meyyappan, M TI Modeling gas flow through microchannels and nanopores SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SIMULATION MONTE-CARLO; NAVIER-STOKES; ZEOLITE MEMBRANES; CARBON NANOTUBES; ANODIC ALUMINA; SINGLE-FILE; DIFFUSION; MIXTURES; DYNAMICS; DEVICES AB Microchannel based systems have emerged as a critical design trend in development of precise control and maneuvering of small devices. In microelectronics, space propulsion and biomedical areas, these systems are especially useful. Nanoscale pores are recently becoming of great interest due to their beneficial drag and heat transfer properties. However it is difficult to predict the flow performance of these microsystems and nanosystems numerically since the standard assumptions of using Navier-Stokes equations break down at micrometer scales, while the computational times of applicable molecular-dynamics codes become exorbitant. A two-dimensional finite-element based microscale flow model is developed to efficiently predict the overall flow characteristics up to the transition regime for reasonably high Knudsen number flow inside microchannels and nanopores. Presented two-dimensional numerical results for Poiseuille flow of a simple fluid through the microchannel are comparable to the numerical and experimental data published in the literature. The nanopore solutions are also validated with presented experimental data. (C) 2003 American Institute of Physics. C1 Kettering Univ, Dept Mech Engn, Computat Plasma Dynam Lab, Flint, MI 48504 USA. NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Roy, S (reprint author), Kettering Univ, Dept Mech Engn, Computat Plasma Dynam Lab, Flint, MI 48504 USA. RI Roy, Subrata/A-7493-2009 NR 46 TC 178 Z9 201 U1 12 U2 76 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 APR 15 PY 2003 VL 93 IS 8 BP 4870 EP 4879 DI 10.1063/1.1559936 PG 10 WC Physics, Applied SC Physics GA 660YL UT WOS:000181863100077 ER PT J AU Schwenke, DW AF Schwenke, DW TI First principles prediction of isotopic shifts in H2O SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID BORN-OPPENHEIMER APPROXIMATION; POTENTIAL-ENERGY SURFACE; VIBRATION-ROTATION LEVELS; GROUND-STATE; WATER; MOLECULES; INTENSITIES; (D2O)-O-16; STRENGTHS; CM(-1) AB We compute isotope-independent first- and second-order corrections to the Born-Oppenheimer approximation for water and use them to predict isotopic shifts. For the diagonal correction, we use internally contracted multireference configuration interaction wave functions and derivatives with respect to mass-dependent internal coordinates to generate the mass-independent correction functions. For the nonadiabatic correction, we use a self-consistent field wave function for the ground electronic state and single excitation configuration interaction wave functions for the excited states and a generalization of the Handy, Yamaguchi, and Schaefer method to obtain mass-independent correction functions. We find that including the nonadiabatic correction gives significantly improved results compared to just including the diagonal correction when the Born-Oppenheimer potential energy surface is optimized for (H2O)-O-16. The agreement with experimental results for deuterium- and tritium-containing isotopes is nearly as good as our best empirical correction, however, the present correction is expected to be more reliable for higher, uncharacterized, levels. (C) 2003 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Schwenke, DW (reprint author), NASA, Ames Res Ctr, MS T27B-1, Moffett Field, CA 94035 USA. RI schwenke, david/I-3564-2013 NR 28 TC 27 Z9 27 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 2003 VL 118 IS 15 BP 6898 EP 6904 DI 10.1063/1.1561053 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 662KE UT WOS:000181945200021 ER PT J AU Dingemans, T Photinos, DJ Samulski, ET Terzis, AF Wutz, C AF Dingemans, T Photinos, DJ Samulski, ET Terzis, AF Wutz, C TI Ordering of apolar and polar solutes in nematic solvents SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID LIQUID-CRYSTALLINE MATERIALS; ELECTRIC-DIPOLE INTERACTIONS; NUCLEAR MAGNETIC-RESONANCE; MAGIC-ANGLE; ORIENTATIONAL ORDER; POLYMER SURFACES; NMR; MOLECULES; PHASE; SIMULATIONS AB The quadrupolar splittings of deuteriated para- and ortho-dichlorobenzene (1,4-DCB and 1,2-DCB, respectively) are measured by nuclear magnetic resonance (NMR) in the nematic solvents hexyl- and pentyloxy-substituted diphenyl diacetylene (DPDA-C6 and DPDA-OC5, respectively). Measurements are taken for all four combinations of the nominally apolar (1,4-DCB) and polar (1,2-DCB) solutes in the apolar (DPDA-C6) and polar (DPDA-OC5) solvents, and throughout the entire nematic temperature range of the solutions. The temperature dependence of the second-rank orientational order parameters of the solutes are obtained from these measurements and the respective order parameters of the mesogenic cores of solvent molecules are obtained independently from carbon-13 NMR measurements. The order parameter profiles of the two solutes are found to be very different but show little variation from one solvent to the other. The results are analyzed and interpreted in terms of the underlying molecular interactions using atomistic solvent-solute potentials. The influence of electrostatic interactions on solute ordering is directly evaluated by computing the order parameters with and without the electrostatic component of the atomistic potential. It is observed to be small. It is also found that the important interactions in these solvent-solute systems are operative over short intermolecular distances for which the representation of the partial charge distributions in terms of overall molecular dipole and quadrupole moments is not valid. (C) 2003 American Institute of Physics. C1 Univ Patras, Dept Phys, Patras 26500, Greece. NASA, ICASE Struct & Mat, Langley Res Ctr, Hampton, VA 23681 USA. Univ Patras, Dept Mat Sci, Patras 26500, Greece. Univ N Carolina, Dept Chem, Chapel Hill, NC 27599 USA. Inst Tech & Makromol Chem, D-20146 Hamburg, Germany. RP Terzis, AF (reprint author), Univ Patras, Dept Phys, Patras 26500, Greece. RI Dingemans, Theo/E-3532-2017 NR 47 TC 25 Z9 26 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 2003 VL 118 IS 15 BP 7046 EP 7061 DI 10.1063/1.1560941 PG 16 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 662KE UT WOS:000181945200035 ER PT J AU Lee, KM Park, JH Kim, Y Choi, W Cho, HK Massie, ST Sasano, Y Yokota, T AF Lee, KM Park, JH Kim, Y Choi, W Cho, HK Massie, ST Sasano, Y Yokota, T TI Properties of polar stratospheric clouds observed by ILAS in early 1997 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE PSCs; aerosols; remote sensing; nitric acid trihydrates ID LIMB-ATMOSPHERIC-SPECTROMETER; AIRBORNE LIDAR OBSERVATIONS; COMPLEX REFRACTIVE-INDEXES; INFRARED OPTICAL-CONSTANTS; NITRIC-ACID TRIHYDRATE; ABSORPTION-SPECTRA; PARTICLES; AEROSOL; TEMPERATURES; GROWTH AB [1] The relative extinction coefficients for Arctic polar stratospheric clouds (PSCs) are determined using a transmittance-ratio technique from spectral data observed in early 1997 by the Improved Limb Atmospheric Spectrometer (ILAS). The observed relative extinction coefficients are compared with theoretical coefficients calculated by the Mie theory for single mode lognormal size distributions of PSCs. The observed PSCs are then classified into three types: nitric acid droplets (HNO3/H2O), and nitric acid trihydrate (NAT) solid particles in the form of alpha-NAT and beta-NAT. However, the definitive detection of alpha-NAT is difficult due to uncertainties of atmospheric temperature measurements and laboratory determination of refractive indices. C1 Kyungpook Natl Univ, Dept Astron & Atmospher Sci, Taegu 702701, South Korea. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Seoul Natl Univ, Sch Earth & Environm Sci, Seoul 151742, South Korea. Natl Inst Environm Studies, Div Atmospher Environm, Tsukuba, Ibaraki 3058506, Japan. Yonsei Univ, Dept Atmospher Sci, Global Environm Res Lab, Seoul 120749, South Korea. RP Lee, KM (reprint author), Kyungpook Natl Univ, Dept Astron & Atmospher Sci, 1370 Sankyuck Dong, Taegu 702701, South Korea. EM kmlee@bh.knu.ac.kr; yoonjae@strat.snu.ac.kr; wchoi@plaza.snu.ac.kr; chk@atmos.yonsei.ac.kr; massie@acd.ucar.edu; sasano@nies.go.jp; yoko@nies.go.jp RI Sasano, Yasuhiro/C-2927-2009 OI Sasano, Yasuhiro/0000-0001-7470-5642 NR 41 TC 5 Z9 5 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 15 PY 2003 VL 108 IS D7 AR 4228 DI 10.1029/2002JD002854 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 677ZJ UT WOS:000182839600012 ER PT J AU Colaprete, A Toon, OB AF Colaprete, A Toon, OB TI Carbon dioxide clouds in an early dense Martian atmosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars; carbon dioxide clouds; greenhouse warming ID EARLY MARS; EARLY EARTH; ICE CLOUDS; CO2; CLIMATE; CONDENSATION; ABSORPTION; NUCLEATION AB We use a time-dependent, microphysical cloud model to study the formation of carbon dioxide clouds in the Martian atmosphere. Laboratory studies by Glandorf et al. [2002] show that high critical supersaturations are required for CO2 cloud particle nucleation and that surface kinetic growth is not limited. These conditions, which are similar to those for cirrus clouds on Earth, lead to the formation of carbon dioxide ice particles with radii greater than 500 mm and concentrations less than 0.1 cm(-3) for typical atmospheric conditions. Within the current Martian atmosphere, CO2 cloud formation is possible at the poles during winter and possibly at high altitudes in the tropics. In both cases, temperature perturbations of several degrees below the CO2 saturation temperature are required to nucleate new cloud particles, suggesting that dynamical processes are the most common initiators of carbon dioxide clouds rather than diabatic cooling. The microphysical cloud model, coupled to a two-stream radiative transfer model, is used to reexamine the impact of CO2 clouds on the surface temperature within a dense CO2 atmosphere. The formation of carbon dioxide clouds leads to a warmer surface than what would be expected for clear sky conditions, but it also warms the atmosphere. The amount of surface warming is sensitive to the presence of dust and water vapor in the atmosphere, both of which act to dampen cloud effects. The radiative warming of the atmosphere associated with cloud formation, as well as latent heating, work to dissipate the clouds when present. In these simulations, clouds never last for periods much longer than several days, limiting their overall effectiveness for warming the surface. The time average cloud optical depth is approximately unity leading to a 5-10 K surface warming, depending on the surface pressure. The surface temperature does not rise above the freezing point of liquid water even for pressures as high as 5 bars, at a solar luminosity of 75% the current value. Our model shows that warming of the surface-atmosphere system by carbon dioxide clouds is self-limiting, since by heating the air the clouds cause themselves to dissipate. However, further analysis of the climatic effects of carbon dioxide clouds considering their global distribution and properties is warranted. C1 NASA, Natl Res Council, Atmospher & Space Phys Lab, Ames Res Ctr, Mountain View, CA 94035 USA. Univ Colorado, Atmospher & Space Phys Lab, Program Atmospher & Ocean Sci, Boulder, CO 80309 USA. RP Colaprete, A (reprint author), NASA, Natl Res Council, Atmospher & Space Phys Lab, Ames Res Ctr, Moffett Field,MS 245-3, Mountain View, CA 94035 USA. NR 22 TC 56 Z9 56 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 15 PY 2003 VL 108 IS E4 AR 5025 DI 10.1029/2002JE001967 PG 23 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 673RU UT WOS:000182594600002 ER PT J AU Rinsland, CP Goldman, A Stephen, TM Chiou, LS Mahieu, E Zander, R AF Rinsland, CP Goldman, A Stephen, TM Chiou, LS Mahieu, E Zander, R TI SF6 ground-based infrared solar absorption measurements: long-term trend, pollution events, and a search for SF5CF3 absorption SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID SULFUR-HEXAFLUORIDE; SPECTROSCOPIC MEASUREMENTS; ERROR ANALYSIS; OZONE; COEFFICIENTS; SINKS AB Infrared solar spectra recorded with the Fourier transform spectrometer in the McMath solar telescope complex on Kitt Peak (31.9degreesN latitude, 111.6degreesW, 2.09 km altitude), southwest of Tucson, Arizona, have been analyzed to retrieve average SF6 tropospheric mixing ratios over a two-decade time span. The analysis is based primarily on spectral fits to absorption by the intense, unresolved nu(3) band Q branch at 947.9 cm(-1). A best fit to measurements recorded with SF6 near typical background concentrations yields a SF6 increase in the average tropospheric mixing ratio from 1.13 pptv (10(-12) per unit volume) in March 1982 to 3.77 pptv in March 2002. The long-term increase by a factor of 3.34 over the time span is consistent with the rapid growth of surface mixing ratios measured in situ at Northern Hemisphere remote stations, though the infrared measurements show a large scatter. Average tropospheric mixing ratio enhancements above background by 2-3 orders of magnitude have been identified in spectra recorded on 5 days between November 1988 and April 1997. These spectra were individually analyzed in an attempt to detect the strongest 8-12 mum band of SF5CF3, a molecule recently identified with an atmospheric growth that has closely paralleled the rise in SF6 during the past three decades. Absorption by the strongest SF5CF3 band was predicted to be above the noise level in the Kitt Peak spectrum with the highest average mean tropospheric SF6 mixing ratio, assuming the reported atmospheric SF5CF3/SF6 ratio and a room temperature absorption cross sections reported for the SF5CF3 903-cm(-1) band. An upper limit of 8 x 10(15) molecules cm(-2) for the SF5CF3 total column was estimated for this case. We hypothesize that the highly elevated SF6 levels above Kitt Peak resulted from a local release experiment rather than production via electrochemical fluoridation of intermediate products, the proposed source of atmospheric SF5CF3. The absence of the SF5CF3 feature in the spectra with elevated SF6 is consistent with the absence of SF5CF3 reported in a pure SF6 sample. Published by Elsevier Science Ltd. C1 NASA, Div Atmospher Sci, Langley Res Ctr, Hampton, VA 23681 USA. Univ Denver, Dept Phys, Denver, CO 80208 USA. Wyle Labs, Hampton, VA 23698 USA. Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium. RP Rinsland, CP (reprint author), NASA, Div Atmospher Sci, Langley Res Ctr, Mail Stop 401A,21 Langley Blvd, Hampton, VA 23681 USA. OI Mahieu, Emmanuel/0000-0002-5251-0286 NR 29 TC 12 Z9 13 U1 0 U2 6 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 APR 15 PY 2003 VL 78 IS 1 BP 41 EP 53 AR PII S0022-4073(02)00177-2 DI 10.1016/S0022-4073(02)00177-2 PG 13 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 649TL UT WOS:000181224000003 ER PT J AU Savchenkov, AA Ilchenko, VS Handley, T Maleki, L AF Savchenkov, AA Ilchenko, VS Handley, T Maleki, L TI Ultraviolet-assisted frequency trimming of optical microsphere resonators SO OPTICS LETTERS LA English DT Article ID WHISPERING-GALLERY MODES; STRAIN AB We have demonstrated the engineering of a precise shift in the resonance frequency of high-Q (101) whispering-gallery modes in microspheres of germanium-doped silica with UV irradiation. With 600 mW of 351-nm radiation from an Ar-ion laser, 18-GHz permanent frequency shifts were obtained for modes of 1550-nm wavelength, enough to tune a resonance over a full free spectral range. (C) 2003 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Savchenkov, AA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 9 Z9 9 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD APR 15 PY 2003 VL 28 IS 8 BP 649 EP 650 DI 10.1364/OL.28.000649 PG 2 WC Optics SC Optics GA 663CR UT WOS:000181989100021 PM 12703929 ER PT J AU Chung, DJH AF Chung, DJH TI Classical inflaton field induced creation of superheavy dark matter SO PHYSICAL REVIEW D LA English DT Article ID ENERGY COSMIC-RAYS; PARTICLE-PRODUCTION; INFLATIONARY UNIVERSE; ADIABATIC REGULARIZATION; SUPERSYMMETRY BREAKING; GRAVITINO PRODUCTION; DECAY; BARYOGENESIS; COSMOLOGY; RESONANCE AB We calculate analytically and numerically the production of superheavy dark matter (scalar field X) when it is coupled to the inflaton field phi within the context of a slow-roll m(phi)(2)phi(2)/2 inflationary model with coupling g(2)X(2)phi(2)/2. We find that X particles with a mass as large as 1000H(i), where H-i is the value of the Hubble expansion rate at the end of inflation, can be produced in sufficient abundance to be cosmologically significant today. This means that superheavy dark matter may have a mass of up to 10(-3)M(Pl). We also derive a simple formula that can be used to estimate particle production as a result of a quantum field's interaction with a general class of homogeneous classical fields. Finally, we note that the combined effect of the inflaton field and the gravitational field on the X field causes the production to be a nonmonotonic function of g(2). C1 Univ Chicago, Dept Phys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Univ Chicago, Dept Phys, Chicago, IL 60637 USA. EM djchung@feynman.physics.lsa.umich.edu NR 75 TC 42 Z9 42 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 APR 15 PY 2003 VL 67 IS 8 AR 083514 DI 10.1103/PhysRevD.67.083514 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 675ZV UT WOS:000182728200028 ER PT J AU Frieman, JA Huterer, D Linder, EV Turner, MS AF Frieman, JA Huterer, D Linder, EV Turner, MS TI Probing dark energy with supernovae: Exploiting complementarity with the cosmic microwave background SO PHYSICAL REVIEW D LA English DT Article ID EQUATION-OF-STATE; COSMOLOGICAL CONSTANT; IA SUPERNOVAE; GOLDSTONE BOSONS; POWER SPECTRUM; CONSTRAINTS; UNIVERSE; ANISOTROPIES; PARAMETERS; DENSITY AB A primary goal for cosmology and particle physics over the coming decade will be to unravel the nature of the dark energy that drives the accelerated expansion of the Universe. In particular, the determination of the equation-of-state of dark energy wequivalent top/rho and its time variation dw/dz will be critical for developing a theoretical understanding of the new physics behind this phenomenon. Type Ia supernovae (SNe) and cosmic microwave background (CMB) anisotropy are each sensitive to the dark energy equation of state. SNe alone can determine w(z) with some precision, while CMB anisotropy alone cannot because of a strong degeneracy between the matter density Omega(M) and w. However, we show that the Planck CMB mission can significantly improve the power of a deep SNe survey to probe w and especially dw/dz. Because CMB constraints are nearly orthogonal to SNe constraints in the Omega(M)-w plane, for constraining w(z) Planck is more useful than precise determination of Omega(M). We discuss how the CMB/SNe complementarity impacts strategies for the redshift distribution of a supernova survey to determine w(z) and conclude that a well-designed sample should include a substantial number of supernovae out to redshifts zsimilar to2. C1 Univ Chicago, Dept Astron & Astrophys, Ctr Cosmol Phys, Chicago, IL 60637 USA. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Case Western Reserve Univ, Dept Phys, Cleveland, OH 44106 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Berkeley, CA 94720 USA. Univ Chicago, Enrico Fermi Inst, Dept Phys, Chicago, IL 60637 USA. RP Univ Chicago, Dept Astron & Astrophys, Ctr Cosmol Phys, 5640 S Ellis Ave, Chicago, IL 60637 USA. NR 51 TC 60 Z9 60 U1 0 U2 1 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 2003 VL 67 IS 8 AR 083505 DI 10.1103/PhysRevD.67.083505 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 675ZV UT WOS:000182728200019 ER PT J AU Li, J Ye, Q Cassell, A Ng, HT Stevens, R Han, J Meyyappan, M AF Li, J Ye, Q Cassell, A Ng, HT Stevens, R Han, J Meyyappan, M TI Bottom-up approach for carbon nanotube interconnects SO APPLIED PHYSICS LETTERS LA English DT Article ID CONDUCTIVITY AB We report a bottom-up approach to integrate multiwalled carbon nanotubes (MWNTs) into multilevel interconnects in silicon integrated-circuit manufacturing. MWNTs are grown vertically from patterned catalyst spots using plasma-enhanced chemical vapor deposition. We demonstrate the capability to grow aligned structures ranging from a single tube to forest-like arrays at desired locations. SiO2 is deposited to encapsulate each nanotube and the substrate, followed by a mechanical polishing process for planarization. MWNTs retain their integrity and demonstrate electrical properties consistent with their original structure. (C) 2003 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Li, J (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RI Li, Jun/H-7771-2013 OI Li, Jun/0000-0002-3689-8946 NR 20 TC 361 Z9 367 U1 5 U2 65 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 14 PY 2003 VL 82 IS 15 BP 2491 EP 2493 DI 10.1063/1.1566791 PG 3 WC Physics, Applied SC Physics GA 665DT UT WOS:000182104900041 ER PT J AU Wei, CY Cho, K Srivastava, D AF Wei, CY Cho, K Srivastava, D TI Tensile yielding of multiwall carbon nanotubes SO APPLIED PHYSICS LETTERS LA English DT Article ID STRENGTH; ROPES AB The tensile yielding of multiwall carbon nanotubes (MWCNTs) has been studied using molecular-dynamics simulations and a transition state theory based model. We find a strong dependence of the yielding on the strain rate. A critical strain rate has been predicted above/below which yielding strain of a MWCNT is larger/smaller than that of the corresponding single-wall carbon nanotubes (CNTs). At an experimentally feasible strain rate of 1%/h and T=300 K, the yield strain of a MWCNT is estimated to be about 3%-4% higher than that of an equivalent single-wall CNT. This is in good agreement with recent experimental observations. (C) 2003 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Stanford Univ, Dept Mech Engn, Stanford, CA 94305 USA. RP Wei, CY (reprint author), NASA, Ames Res Ctr, MS 229-1, Moffett Field, CA 94035 USA. NR 13 TC 34 Z9 36 U1 1 U2 6 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 14 PY 2003 VL 82 IS 15 BP 2512 EP 2514 DI 10.1063/1.1567041 PG 3 WC Physics, Applied SC Physics GA 665DT UT WOS:000182104900048 ER PT J AU Aviles, H Belay, T Sonnenfeld, G Girten, B Dalton, BP Barrett, J AF Aviles, H Belay, T Sonnenfeld, G Girten, B Dalton, BP Barrett, J TI Induction of tumor necrosis factor-alpha in mice fed a unique foodbar diet SO FASEB JOURNAL LA English DT Meeting Abstract CT 90th Annual Meeting of the American-Association-for-Immunologists CY MAY 06-10, 2003 CL DENVER, COLORADO SP American Assoc Immunologists C1 Morehouse Sch Med, Atlanta, GA 30310 USA. NASA, Ames Res Ctr, Life Sci, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD APR 14 PY 2003 VL 17 IS 7 SU S BP C54 EP C54 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 669TR UT WOS:000182367000251 ER PT J AU Mareth, DR Yamauchi, K Ramji, B Sundaresan, A Pellis, NR Kulkarni, AD AF Mareth, DR Yamauchi, K Ramji, B Sundaresan, A Pellis, NR Kulkarni, AD TI Lymphocyte activation in microgravity and nutritional countermeasure SO FASEB JOURNAL LA English DT Meeting Abstract CT 90th Annual Meeting of the American-Association-for-Immunologists CY MAY 06-10, 2003 CL DENVER, COLORADO SP American Assoc Immunologists C1 Univ Texas, Hlth Sci Ctr, Houston, TX 77030 USA. USRS NASA, Houston, TX USA. JSC NASA, Houston, TX USA. GSBS Houston, Houston, TX USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD APR 14 PY 2003 VL 17 IS 7 SU S BP C230 EP C230 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 669TR UT WOS:000182367001068 ER PT J AU Olsen, MA Douglass, AR Schoeberl, MR AF Olsen, MA Douglass, AR Schoeberl, MR TI A comparison of Northern and Southern Hemisphere cross-tropopause ozone flux SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STRATOSPHERE-TROPOSPHERE EXCHANGE; POTENTIAL VORTICITY; MASS-EXCHANGE; TRANSPORT; CHEMISTRY; BUDGET; MODELS; O-3 AB [1] The downward flux of ozone across the midlatitude (30degrees-60degrees) tropopause is calculated using changes in potential vorticity (PV) and a statistical relationship between the PV changes and ozone flux. This approach separates dynamical aspects of transport from the seasonal cycle of ozone in the lowermost stratosphere. The Northern Hemisphere (NH) ozone flux is larger ( similar to24%) than that calculated in the Southern Hemisphere (SH) during the year 2000. The midlatitude SH total horizontal area of exchange is equal to or slightly greater than the area of exchange in the NH throughout an annual cycle. The mean changes in potential vorticity of parcels near the tropopause are also similar or slightly greater in the SH, suggesting that NH and SH downward air mass transport to the troposphere are comparable. These results show that the greater NH midlatitude ozone flux is mostly due to the amount of ozone available for exchange rather than dynamical differences near the tropopause level at these latitudes. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Olsen, MA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Douglass, Anne/D-4655-2012 NR 24 TC 13 Z9 14 U1 0 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 12 PY 2003 VL 30 IS 7 AR 1412 DI 10.1029/2002GL016538 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 669JR UT WOS:000182348600001 ER PT J AU Cosma-Averseng, S Flamant, C Pelon, J Palm, SP Schwemmer, GK AF Cosma-Averseng, S Flamant, C Pelon, J Palm, SP Schwemmer, GK TI The cloudy atmospheric boundary layer over the subtropical South Atlantic Ocean: Airborne-spaceborne lidar observations and numerical simulations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE atmospheric boundary layer; subtropical South Atlantic Ocean; lidar; meso-NH numerical simulations; Lidar In-Space Technology Experiment ID TECHNOLOGY EXPERIMENT; CORRELATIVE MEASUREMENTS; WIND-SPEED; PARAMETERIZATION; TRANSITION; MODELS; SYSTEM; ASTEX; LITE; STRATOCUMULUS AB [1] This paper focuses on the structure of the marine boundary layer in an convergence region between easterly ( trade winds) and westerly flows, over the Subtropical South Atlantic Ocean on 15 September 1994 using an unprecedented combination of spaceborne and airborne lidar observations, airborne Radar Ocean Wave Spectrometer and dropsondes system, and three-dimensional modeling. Methodologies previously developed to determine the marine atmospheric boundary layer (MABL) depth and cloud top heights from airborne lidar measurements are successfully applied to spaceborne measurements. Nested numerical simulations have been performed in this case study. It is shown that the MABL structure in this region ( observed with lidar and simulated) collapsed dramatically in connection with a marked decrease of wind speed and near-zero turbulent kinetic energy due to specific synoptic conditions. C1 Univ Paris 06, Inst Pierre Simon Laplace, Serv Aeron, F-75252 Paris, France. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Cosma-Averseng, S (reprint author), Univ Paris 06, Inst Pierre Simon Laplace, Serv Aeron, Boite 102,4 Pl Jussieu, F-75252 Paris, France. EM cosma@aero.jussieu.fr; cyf@aero.jussieu.fr; jpe@aero.jussieu.fr; spp@virl.gsfcl.nasa.gov; geary.k.schwemmer@nasa.gov NR 41 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 APR 12 PY 2003 VL 108 IS D7 AR 4220 DI 10.1029/2002JD002368 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 669KH UT WOS:000182350100001 ER PT J AU Ichoku, C Remer, LA Kaufman, YJ Levy, R Chu, DA Tanre, D Holben, BN AF Ichoku, C Remer, LA Kaufman, YJ Levy, R Chu, DA Tanre, D Holben, BN TI MODIS observation of aerosols and estimation of aerosol radiative forcing over southern Africa during SAFARI 2000 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE MODIS; aerosol; radiative forcing; atmosphere; SAFARI; southern Africa ID OPTICAL-THICKNESS; TRACE-A; TROPOSPHERIC AEROSOL; AIRBORNE SIMULATOR; INITIATIVE SAFARI; SATELLITE; AERONET; ATMOSPHERE; RETRIEVALS; TRANSPORT AB [1] MODIS provides almost complete global coverage daily. Aerosol optical thickness (AOT or tau(alambda)) and other aerosol parameters are retrieved over land and ocean at a spatial scale of 10 km ( level 2), then aggregated to a global grid of 1degrees spatial resolution on daily, weekly, and monthly time scales ( level 3). The SAFARI 2000 ground-based measurements of AOT from the Aerosol Robotic Network (AERONET) group of Sun photometers were used to compare MODIS over-land AOT based on a spatiotemporal statistical technique. At low aerosol loading (when tau(a470) < 0.6), MODIS tau(a lambda) values agree with those of AERONET at the blue wavelength (lambda = 440, 470 nm). But, at higher wavelengths and with increasing aerosol loading, MODIS AOT values underestimate those of AERONET. There are also regional variations in validation accuracy. This AOT underestimation by MODIS during SAFARI 2000 is attributed to the application of a constant single-scattering-albedo (SSA or omega(0)) value of 0.90 globally for smoke aerosol retrieval. Recent studies based on long-term observations with AERONET Sun photometers suggest that lower omega(0) values of 0.88 and 0.84 at 440 nm and 670 nm wavelengths respectively would be more applicable over southern Africa ( particularly over Zambia, where most of the measurements were based). A column climate model, with MODIS aerosol information as input, is used to calculate aerosol radiative forcing over the ( southern Atlantic) Ocean part of the SAFARI 2000 region. For September 2000, the results show a forcing of -10 W/m(2) at the top of the atmosphere and approximately -26 W/m(2) at the terrestrial surface. C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Atmospheres Lab, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. Univ Sci & Technol Lille, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. CNRS, Opt Atmospher Lab, Villeneuve Dascq, France. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Ichoku, C (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Atmospheres Lab, Code 913, Greenbelt, MD 20771 USA. EM ichoku@climate.gsfc.nasa.gov; Lorraine.A.Remer@nasa.gov; yoram.j.kaufman@nasa.gov; levy@climate.gsfc.nasa.gov; achu@climate.gsfc.nasa.gov; Didier.Tanre@univ-lille1.fr; Brent.N.Holben@nasa.gov RI Ichoku, Charles/E-1857-2012; Levy, Robert/M-7764-2013 OI Ichoku, Charles/0000-0003-3244-4549; Levy, Robert/0000-0002-8933-5303 NR 41 TC 77 Z9 78 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 12 PY 2003 VL 108 IS D13 AR 8499 DI 10.1029/2002JD002366 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 669KU UT WOS:000182351100002 ER PT J AU Dye, DG Tucker, CJ AF Dye, DG Tucker, CJ TI Seasonality and trends of snow-cover, vegetation index, and temperature in northern Eurasia SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATMOSPHERIC CO2; HEMISPHERE; CYCLE AB [1] We examine seasonal variability in snow-cover, normalized difference vegetation index (NDVI), and temperature in a broad region of northern Eurasia, and the spatial and temporal correspondence among trends in these variables between 1982 and 1999. Our results support the contention that the previously reported springtime "greening'' trend in northern Eurasian land areas arises from a combination of: (1) the direct effects of declining snow-cover on surface spectral reflectance and NDVI, and (2) enhanced vegetation growth and green biomass stimulated by warmer air temperatures and potentially greater vegetation absorption of photosynthetically active radiation (PAR) during the period of annual peak solar irradiance. C1 FRSGC, Kanazawa Ku, Ecosyst Change Res Program, Kanagawa 2360001, Japan. NASA, Terr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Dye, DG (reprint author), FRSGC, Kanazawa Ku, Ecosyst Change Res Program, 3173-25 Showa Machi, Kanagawa 2360001, Japan. EM dye@jamstec.go.jp NR 13 TC 64 Z9 64 U1 1 U2 19 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 11 PY 2003 VL 30 IS 7 AR 1405 DI 10.1029/2002GL016384 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 669JP UT WOS:000182348400003 ER PT J AU Yoder, CF Konopliv, AS Yuan, DN Standish, EM Folkner, WM AF Yoder, CF Konopliv, AS Yuan, DN Standish, EM Folkner, WM TI Fluid core size of mars from detection of the solar tide SO SCIENCE LA English DT Article ID INTERIOR STRUCTURE; GRAVITY-FIELD; MODEL; PATHFINDER; TRACKING AB The solar tidal deformation of Mars, measured by its k(2) potential Love number, has been obtained from an analysis of Mars Global Surveyor radio tracking. The observed k(2) of 0.153 +/- 0.017 is large enough to rule out a solid iron core and so indicates that at least the outer part of the core is liquid. The inferred core radius is between 1520 and 1840 kilometers and is independent of many interior properties, although partial melt of the mantle is one factor that could reduce core size. Ice-cap mass changes can be deduced from the seasonal variations in air pressure and the odd gravity harmonic J(3), given knowledge of cap mass distribution with latitude. The south cap seasonal mass change is about 30 to 40% larger than that of the north cap. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Charles.F.Yoder@jpl.nasa.gov; Alex.Konopliv@jpl.nasa.gov NR 22 TC 164 Z9 171 U1 3 U2 16 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 11 PY 2003 VL 300 IS 5617 BP 299 EP 303 DI 10.1126/science.1079645 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 665RQ UT WOS:000182135400048 PM 12624177 ER PT J AU Notholt, J Kuang, ZM Rinsland, CP Toon, GC Rex, M Jones, N Albrecht, T Deckelmann, H Krieg, J Weinzierl, C Bingemer, H Weller, R Schrems, O AF Notholt, J Kuang, ZM Rinsland, CP Toon, GC Rex, M Jones, N Albrecht, T Deckelmann, H Krieg, J Weinzierl, C Bingemer, H Weller, R Schrems, O TI Enhanced upper tropical tropospheric COS: Impact on the stratospheric aerosol layer SO SCIENCE LA English DT Article ID CARBONYL SULFIDE; ATMOSPHERIC CHEMISTRY; TRANSPORT; EMISSION; PACIFIC; PROJECT; GASES; OZONE; MODEL; NO AB Carbonyl sulfide (COS) is considered to be a major source of the stratospheric sulfate aerosol during periods of volcanic quiescence. We measured COS at the tropical tropopause and find mixing ratios to be 20 to 50% larger than are assumed in models. The enhanced COS levels are correlated with high concentrations of biomass-burning pollutants like carbon monoxide ( CO) and hydrogen cyanide (HCN). The analysis of backward trajectories and global maps of. re statistics suggest that biomass-burning emissions transported upward by deep convection are the source of the enhanced COS in the upper tropical troposphere. C1 Univ Bremen, D-28334 Bremen, Germany. CALTECH, Pasadena, CA 91125 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Alfred Wegener Inst Polar & Marine Res, D-14473 Potsdam, Germany. Univ Wollongong, Wollongong, NSW 2522, Australia. Goethe Univ Frankfurt, D-60325 Frankfurt, Germany. Alfred Wegener Inst Polar & Marine Res, D-27568 Bremerhaven, Germany. RP Notholt, J (reprint author), Univ Bremen, D-28334 Bremen, Germany. EM jnotholt@iup.physik.uni-bremen.de RI Rex, Markus/A-6054-2009; Jones, Nicholas/G-5575-2011; Notholt, Justus/P-4520-2016 OI Rex, Markus/0000-0001-7847-8221; Jones, Nicholas/0000-0002-0111-2368; Notholt, Justus/0000-0002-3324-885X NR 32 TC 55 Z9 55 U1 3 U2 17 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 11 PY 2003 VL 300 IS 5617 BP 307 EP 310 DI 10.1126/science.1080320 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 665RQ UT WOS:000182135400050 PM 12690193 ER PT J AU Xu, CK Lonsdale, CJ Shupe, DL Franceschini, A Martin, C Schiminovich, D AF Xu, CK Lonsdale, CJ Shupe, DL Franceschini, A Martin, C Schiminovich, D TI Models for evolution of dusty and E/S0 galaxies seen in multiband surveys SO ASTROPHYSICAL JOURNAL LA English DT Review DE galaxies : luminosity function, mass function; galaxies : Seyfert; galaxies : starburst; infrared : galaxies ID HUBBLE-DEEP-FIELD; STAR-FORMATION RATE; SPECTRAL ENERGY-DISTRIBUTIONS; EXTRAGALACTIC SOURCE COUNTS; AREA ISO SURVEY; ULTRALUMINOUS INFRARED GALAXIES; ALPHA LUMINOSITY FUNCTION; HIGH-REDSHIFT GALAXIES; K-BAND; FORMATION HISTORY AB Phenomenological models for evolution of dusty and E/S0 galaxies, respectively, are developed to address two major questions concerning galaxy populations in deep infrared (IR) surveys: (1) Do normal late-type galaxies or starburst galaxies ( including galaxies with obscured active galactic nuclei) dominate among sources in deep IR surveys? (2) How much do E/S0 galaxies contribute to the counts in deep mid-infrared (MIR: 3-20 mum) surveys? Among three new models for evolution of dusty galaxies, it is assumed in model S1 that starburst galaxies are the dominant population and in model S2 that normal galaxies dominate. Model S3 is an intermediate model. Comparing the model predictions with a wide range of observational data collected from the literature, we find that none of these models can be ruled out, given the uncertainties of the data. We show that the most direct method to distinguish these models is to compare the predicted color distributions of IR galaxies with observations, which will soon be available from the SIRTF Wide-Area Infrared Extragalactic (SWIRE) survey. The models for E/S0 galaxies follow a simple passive evolution approach. Among the three E/S0 models (E1, E2, and E3) investigated in this paper, model E2, which is specified by a peak formation redshift z(peak) = 2 and an e-folding formation timescale omega = 2 Gyr, fits the data best. This suggests a synchronization between the evolution of E/S0 galaxies and that of starburst galaxies, in the sense that the peak of the formation function of E/S0 galaxies (z(peak) = 2) is close to the peak of the evolution functions of starburst galaxies (z(peak) = 1.4). We find that E/S0 galaxies contribute about 10%-30% of the counts in the MIR bands of less than 10 mum and up to 30%-50% of the optical/near-IR counts in the bright end. Their contributions to counts in the UV (2000 Angstrom) and in the longer wavelength IR (greater than or equal to12 mum) bands are negligible. Taking into account this contribution, new predictions for counts and confusion limits in the SIRTF bands are presented. C1 CALTECH, Ctr Infrared Proc & Anal, Jet Propuls Lab, Pasadena, CA 91125 USA. Univ Padua, Dipartimento Astron, I-35122 Padua, Italy. RP CALTECH, Ctr Infrared Proc & Anal, Jet Propuls Lab, MS 100-22, Pasadena, CA 91125 USA. NR 119 TC 48 Z9 48 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 2003 VL 587 IS 1 BP 90 EP 116 DI 10.1086/368069 PN 1 PG 27 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 665EA UT WOS:000182105600008 ER PT J AU Galama, TJ Reichart, D Brown, TM Kimble, RA Price, PA Berger, E Frail, DA Kulkarni, SR Yost, SA Gal-Yam, A Bloom, JS Harrison, FA Sari, R Fox, D Djorgovski, SG AF Galama, TJ Reichart, D Brown, TM Kimble, RA Price, PA Berger, E Frail, DA Kulkarni, SR Yost, SA Gal-Yam, A Bloom, JS Harrison, FA Sari, R Fox, D Djorgovski, SG TI Hubble Space Telescope and ground-based optical and ultraviolet observations of GRB 010222 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID GAMMA-RAY BURST; 25 APRIL 1998; AFTERGLOW EMISSION; UNUSUAL SUPERNOVA; LIGHT CURVES; HOST GALAXY; GRB 970228; FOLLOW-UP; DUST; JETS AB We report on Hubble Space Telescope (HST) Wide Field Planetary Camera 2 optical and Space Telescope Imaging Spectrograph (STIS) near-ultraviolet MAMA observations and ground-based optical observations of GRB 010222, spanning 15 hr to 71 days. The observations are well described by a relativistic blast wave model with a hard electron energy distribution, p = 1.57(-0.03)(+0.04) and a jet transition at t(*) = 0.93(-0.06)(+0.15) days. These values are slightly larger than previously found as a result of a correction for the contribution from the host galaxy to the late-time ground-based observations and the larger temporal baseline provided by the HST observations. The host galaxy is found to contain a very compact core ( size <0.&DPRIME;25), which coincides with the position of the optical transient. The STIS near-ultraviolet MAMA observations allow for an investigation of the extinction properties along the line of sight to GRB 010222. We find that the far-ultraviolet curvature component c(4) is rather large. In combination with the low optical extinction, A(V) = 0.110(-0.021)(+0.010) mag, when compared with the hydrogen column inferred from X- ray observations, we suggest that this is evidence for dust destruction. C1 CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. RP Galama, TJ (reprint author), CALTECH, Div Phys Math & Astron, MS 105-24, Pasadena, CA 91125 USA. RI Kimble, Randy/D-5317-2012; Galama, Titus/D-1429-2014; OI Galama, Titus/0000-0002-1036-396X; Brown, Thomas/0000-0002-1793-9968 NR 67 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 2003 VL 587 IS 1 BP 135 EP 142 DI 10.1086/368123 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 665EA UT WOS:000182105600012 ER PT J AU Ward, JS Zmuidzinas, J Harris, AI Isaak, KG AF Ward, JS Zmuidzinas, J Harris, AI Isaak, KG TI A (CO)-C-12 J=6-5 map of M82: The significance of warm molecular gas SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (M82); galaxies : ISM; galaxies : starburst; submillimeter ID FAR-INFRARED SPECTROSCOPY; STARBURST NUCLEUS; CARBON-MONOXIDE; CLOUDS; SUBMILLIMETER; CO; EMISSION; LINES; EXCITATION; GALAXIES AB We present a (CO)-C-12 J = 6-5 map of the nuclear regions of the starburst galaxy M82 at a resolution of 14" taken at the Caltech Submillimeter Observatory (CSO). Hot spots were found on either side of the dynamical center. We compare our results with a high-resolution (CO)-C-12 J = 2-1 interferometer map, and present a (CO)-C-12 J = 6-5/(CO)-C-12 J = 2-1 line ratio map obtained using a novel deconvolution technique. This line ratio is highest at the two J = 6-5 integrated intensity peaks, reaching 0.4 and 0.5 in the northeast and southwest peaks, respectively, and is typically 0.2 elsewhere in the nuclear region. We also present measurements of (CO)-C-12 J = 4-3, (CO)-C-12 J = 3-2, and (CO)-C-13 J = 3-2, and an upper limit for (CO)-C-13 J = 6-5. We analyze these observations in the context of a two-component large velocity gradient (LVG) excitation model. Likelihood density curves were calculated for each of the model parameters and a variety of related physical quantities for the northeast and southwest peaks based on the measured line intensities and their associated uncertainties. This approach reveals in an unbiased way how well various quantities can be constrained by the CO observations. We find that the beam-averaged (CO)-C-12 and (CO)-C-13 column densities, the isotopomer abundance ratio, and the area filling factors are among the best constrained quantities, while the cool component H-2 density and pressure are less well constrained. The results of this analysis suggest that the warm gas is less dense than the cool gas, and that over half of the total molecular gas mass in these nuclear regions is warmer than 50 K. C1 CALTECH, Dept Phys, Pasadena, CA 91125 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Ward, JS (reprint author), Jet Prop Lab, Mail Stop 168-314,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM john.ward@jpl.nasa.gov; jonas@submm.caltech.edu; harris@astro.umd.edu; isaak@mrao.cam.ac.uk NR 28 TC 61 Z9 61 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 2003 VL 587 IS 1 BP 171 EP 185 DI 10.1086/368175 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 665EA UT WOS:000182105600015 ER PT J AU Weisman, JL Lee, TJ Salama, F Head-Gordon, M AF Weisman, JL Lee, TJ Salama, F Head-Gordon, M TI Time-dependent density functional theory calculations of large compact polycyclic aromatic hydrocarbon cations: Implications for the diffuse interstellar bands SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; ISM : molecules; methods : analytical ID EXCITATION-ENERGIES; ELECTRONIC-SPECTRA; SPECTROSCOPY; CARRIERS; APPROXIMATION; EQUILIBRIA; ABSORPTION; PERYLENE; STATES; PAHS AB We investigate the electronic absorption spectra of several maximally pericondensed polycyclic aromatic hydrocarbon radical cations with time-dependent density functional theory calculations. We find interesting trends in the vertical excitation energies and oscillator strengths for this series containing pyrene through circumcircumcoronene, the largest species containing close to 100 carbon atoms. We discuss the implications of these new results for the size and structure distribution of the diffuse interstellar band carriers. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Weisman, JL (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Lee, Timothy/K-2838-2012; Salama, Farid/A-8787-2009 OI Salama, Farid/0000-0002-6064-4401 NR 29 TC 54 Z9 54 U1 1 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 APR 10 PY 2003 VL 587 IS 1 BP 256 EP 261 DI 10.1086/368103 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 665EA UT WOS:000182105600021 ER PT J AU Wolfire, MG McKee, CF Hollenbach, D Tielens, AGGM AF Wolfire, MG McKee, CF Hollenbach, D Tielens, AGGM TI Neutral atomic phases of the interstellar medium in the Galaxy SO ASTROPHYSICAL JOURNAL LA English DT Review DE ISM : clouds; ISM : general; ISM : structure ID H-II REGIONS; POLYCYCLIC AROMATIC-HYDROCARBONS; INTER-STELLAR MEDIUM; WARM IONIZED MEDIUM; FINE-STRUCTURE EXCITATION; 21 CENTIMETER ABSORPTION; THERMALLY BISTABLE FLOW; HIGH-VELOCITY CLOUDS; SOUTHERN MILKY-WAY; GAMMA-RAY EMISSION AB Much of the interstellar medium in disk galaxies is in the form of neutral atomic hydrogen, H I. This gas can be in thermal equilibrium at relatively low temperatures, T less than or similar to 300 K (the cold neutral medium [CNM]), or at temperatures somewhat less than 104 K (the warm neutral medium [WNM]). These two phases can coexist over a narrow range of pressures, P(min) less than or equal to P less than or equal to P(max). We determine P(min) and P(max) in the plane of the Galaxy as a function of Galactocentric radius R using recent determinations of the gas heating rate and the gas-phase abundances of interstellar gas. We provide an analytic approximation for P(min) as a function of metallicity, far-ultraviolet radiation field, and the ionization rate of atomic hydrogen. Our analytic results show that the existence of P(min), or the possibility of a two-phase equilibrium, generally requires that H(+) exceed C(+) in abundance at P(min). The abundance of H(+) is set by EUV/soft X-ray photoionization and by recombination with negatively charged polycyclic aromatic hydrocarbons. In order to assess whether thermal or pressure equilibrium is a realistic assumption, we de. ne a parameter Y = t(cool)/t(shock), where t(cool) is the gas cooling time and t(shock) is the characteristic shock time or "time between shocks in a turbulent medium.'' For Y < 1 gas has time to reach thermal balance between supernova-induced shocks. We find that this condition is satisfied in the Galactic disk, and thus the two-phase description of the interstellar H I is approximately valid even in the presence of interstellar turbulence. Observationally, the mean density [n(HI)] is often better determined than the local density, and we cast our results in terms of [nHI] as well. Over most of the disk of the Galaxy, the H I must be in two phases: the weight of the H I in the gravitational potential of the Galaxy is large enough to generate thermal pressures exceeding Pmin, so that turbulent pressure fluctuations can produce cold gas that is thermally stable; and the mean density of the H I is too low for the gas to be all CNM. Our models predict the presence of CNM gas to R similar or equal to 16-18 kpc, somewhat farther than previous estimates. An estimate for the typical thermal pressure in the Galactic plane for 3 kpc less than or similar to R less than or similar to 18 kpc is P(th)/k similar or equal to 1.4 x 10(4) expd(-R/5.5 kpc) K cm(-3). At the solar circle, this gives P(th)/k similar or equal to 3000 K cm(-3). We show that this pressure is consistent with the C I*/C I(tot) ratio observed by Jenkins & Tripp and the CNM temperature found by Heiles & Troland. We also examine the potential impact of turbulent heating on our results and provide parameterized expressions for the heating rate as a function of Galactic radius. Although the uncertainties are large, our models predict that including turbulent heating does not significantly change our results and that thermal pressures remain above P(min) to R similar or equal to 18 kpc. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. RP Wolfire, MG (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. EM mwolfire@astro.umd.edu; cmckee@astron.berkeley.edu; hollenbach@ism.arc.nasa.gov; tielens@astro.rug.nl NR 202 TC 466 Z9 467 U1 3 U2 11 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 2003 VL 587 IS 1 BP 278 EP 311 DI 10.1086/368016 PN 1 PG 34 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 665EA UT WOS:000182105600023 ER PT J AU Patel, SK Kouveliotou, C Woods, PM Tennant, AF Weisskopf, MC Finger, MH Wilson, CA Gogus, E van der Klis, M Belloni, T AF Patel, SK Kouveliotou, C Woods, PM Tennant, AF Weisskopf, MC Finger, MH Wilson, CA Gogus, E van der Klis, M Belloni, T TI Chandra observations of the anomalous X-ray pulsar 4U 0142+61 SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : individual (4U 0142+61); stars : neutron; X-rays : stars ID 4U-0142+61; COUNTERPART; SYSTEM AB We present X-ray imaging, timing, and phase-resolved spectroscopy of the anomalous X-ray pulsar 4U 0142+61 using the Chandra X-Ray Observatory. The spectrum is well described by a power-law plus black-body model with Gamma = 3.35(2), kT(BB) = 0.458(3) keV, and N-H = 0.91(2) x 10(22) cm(-2); we find no significant evidence for spectral features (0.5-7.0 keV). Time-resolved X-ray spectroscopy shows evidence for evolution in phase in either Gamma, kT(BB), or some combination thereof as a function of pulse phase. We derive a precise X-ray position for the source and determine its spin period, P = 8.68866(30) s. We have detected emission beyond 4" from the central source and extending beyond 100", likely due to dust scattering in the interstellar medium. C1 Natl Acad Sci, NRC, NSSTC, Huntsville, AL 35805 USA. Univ Space Res Assoc, NSSTC, Huntsville, AL 35805 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Dept Phys, NSSTC SD50, Huntsville, AL 35805 USA. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Natl Inst Nucl & High Energy Phys, Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. Osserv Astron Brera, I-23807 Merate, Lc, Italy. RP Patel, SK (reprint author), Natl Acad Sci, NRC, NSSTC, SD-50, Huntsville, AL 35805 USA. NR 19 TC 40 Z9 41 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 2003 VL 587 IS 1 BP 367 EP 372 DI 10.1086/368072 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 665EA UT WOS:000182105600029 ER PT J AU Harra, LK Sterling, AC AF Harra, LK Sterling, AC TI Imaging and spectroscopic investigations of a solar coronal wave: Properties of the wave front and associated erupting material SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona; Sun : coronal mass ejections (CMEs); Sun : transition region; Sun : UV radiation ID MASS EJECTION; MORETON WAVES; EIT; FLARE; SOHO AB Using spectral data from the Coronal Diagnostic Spectrometer (CDS) instrument on the Solar and Heliospheric Observatory spacecraft, we observe a coronal wave feature (often referred to as an EIT wave) that occurred in association with a solar eruption and. are on 1998 June 13. EUV images from the Transition Region and Coronal Explorer (TRACE) satellite show that the coronal wave consists of two aspects: (1) a "bright wave,'' which shows up prominently in the TRACE difference images, moves with a velocity of approximately 200 km s(-1), and is followed by a strong dimming region behind it and (2) a "weak wave,'' which is faint in the TRACE images, has a velocity of about 500 km s(-1), and appears to disperse out of the bright wave. The weak wave passes through the CDS field of view but shows little or no line-of-sight motions in CDS spectra (velocities less than about 10 km s(-1)). Only a small portion of the bright wave passes the CDS field of view, with the spectral lines showing insignificant shifts. A high-velocity CDS feature, however, occurs after the weak wave passes, which appears to correspond to ejection of cool, filament-like material in TRACE images. Our observations have similarities with a numerical simulation model of coronal waves presented by Chen et al., who suggest that coronal waves consist of a faster propagating, piston-driven portion and a more slowly propagating portion due to the opening of field lines associated with an erupting filament. C1 UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. RP Harra, LK (reprint author), UCL, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England. OI Harra, Louise/0000-0001-9457-6200 NR 21 TC 66 Z9 66 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2003 VL 587 IS 1 BP 429 EP 438 DI 10.1086/368079 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 665EA UT WOS:000182105600036 ER PT J AU Ho, LC Terashima, Y Okajima, T AF Ho, LC Terashima, Y Okajima, T TI A stringent limit on the accretion luminosity of the possible central black hole in the globular cluster M15 SO ASTROPHYSICAL JOURNAL LA English DT Article DE black hole physics; globular clusters : individual (M15); X-rays : general ID HUBBLE-SPACE-TELESCOPE; X-RAY SOURCES; CENTRAL DENSITY CUSP; ENERGY-DISTRIBUTIONS; STAR DISTRIBUTION; GALACTIC NUCLEI; IONIZED-GAS; FLOWS; DYNAMICS; CORE AB The globular cluster M15 has recently been found to host a possible central black hole with a mass of similar to2000 M.. A deep, high-resolution Chandra image failed to detect the "nucleus" of the cluster in X-rays. The upper limit on the X-ray luminosity (L(x) less than or similar to 5.6 x 10(32) ergs s(-1)) corresponds to a bolometric Eddington ratio of L(bol)/L(Edd) less than or similar to (2-4) x 10(-8). Combining this limit with an estimate of the electron density of the intracluster ionized plasma derived from pulsar dispersion measures, we show that the radiative efficiency of the accretion flow, if it accretes at the Bondi rate, must be much lower than that of a standard optically thick, geometrically thin disk. C1 Observ Carnegie Inst Washington, Pasadena, CA 91101 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ho, LC (reprint author), Observ Carnegie Inst Washington, 813 Santa Barbara St, Pasadena, CA 91101 USA. NR 53 TC 26 Z9 26 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2003 VL 587 IS 1 BP L35 EP L38 DI 10.1086/375042 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 665EB UT WOS:000182105700009 ER PT J AU Tsuboi, Y Maeda, Y Feigelson, ED Garmire, GP Chartas, G Mori, K Pravdo, SH AF Tsuboi, Y Maeda, Y Feigelson, ED Garmire, GP Chartas, G Mori, K Pravdo, SH TI Coronal X-ray emission from an intermediate-age brown dwarf SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : coronae; stars : individual (CD-33 degrees 7795B, TWA 5B); stars : low-mass, brown dwarfs; X-rays : stars ID SPLIT-PIXEL EVENTS; LOW-MASS STARS; SPATIAL-RESOLUTION; CLUSTER IC-348; ORION-NEBULA; ASSOCIATION; IMPROVEMENT; NANOFLARES; LP-944-20; REGION AB We report the X-ray detection of the brown dwarf (BD) companion TWA 5B in an similar or equal to12 Myr old pre-main-sequence binary system. We clearly resolve the faint companion (35 photons) separated from the X-ray luminous primary by 2" in a Chandra ACIS image. TWA 5B shows a soft X-ray spectrum with a low plasma temperature of only 0.3 keV and a constant flux during the 3 hr observation, of which the characteristics are commonly seen in the solar corona. The X-ray luminosity is 4 x 10(27) ergs s(-1) (0.1-10 keV band) or log (L-x/L-bol) = -3.4 Comparing these properties to both younger and older BDs, we discuss the evolution of the X- ray emission in BDs. During their first few megayears, they exhibit high levels of X-ray activity, as seen in higher mass pre-main-sequence stars. The level in TWA 5B is still high at t similar or equal to 12 Myr in log L-x/L-bol, while kT has already substantially cooled. C1 Chuo Univ, Dept Sci & Engn, Bunkyo Ku, Tokyo 1128551, Japan. Inst Space & Astronaut Sci, High Energy Astrophys Div, Kanagawa 2298510, Japan. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tsuboi, Y (reprint author), Chuo Univ, Dept Sci & Engn, Bunkyo Ku, Kasuga 1-13-27, Tokyo 1128551, Japan. NR 39 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 2003 VL 587 IS 1 BP L51 EP L54 DI 10.1086/375017 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 665EB UT WOS:000182105700013 ER PT J AU Boy, JP Llubes, M Hinderer, J Florsch, N AF Boy, JP Llubes, M Hinderer, J Florsch, N TI A comparison of tidal ocean loading models using superconducting gravimeter data SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE ocean tidal loading; superconducting gravimeters; Green's functions ID EARTH MODEL; GRAVITY; TIDES; EUROPE AB [1] Errors in global ocean models have been shown to be larger than the accuracy of surface gravity measurements [Baker and Bos, 2001] and also new space gravity missions [Ray et al., 2001]. In this paper, we compare the tidal loading estimated using 10 different ocean tide models to the surface gravity variations observed with 12 superconducting gravimeters (SG) belonging to the Global Geodynamics Project [Crossley et al., 1999] worldwide network. Ocean tidal gravity variations are shown to be mostly dependent on tidal sea height variations within a radius of similar to5000 km. Precise surface gravity measurements are therefore another tool for validating ocean tidal models from short to long wavelengths in addition, for example, to tide gauge data. In this study we also compute the tidal loading using several different available computer codes. As for ocean tidal models, we show that the differences between tidal loading programs are frequently larger than the error estimates of SG measurements. Compared to previous models, both recent hydrodynamical and TOPEX-Poseidon derived tidal models allow a significant reduction of discrepancies between ocean tidal observations using SG and tidal loading estimates. There still remains, however, a nonnegligible in-phase discrepancy between ocean tidal loading estimates and surface gravity observations, whereas the out-of-phase component is much smaller. We have shown that the in-phase disagreement does not seem to be caused by an inaccurate determination of the SG calibration. C1 NASA, Goddard Space Flight Ctr, Space Geodesy Branch, Greenbelt, MD 20771 USA. Univ Paris 06, UMR Sisyphe, F-75252 Paris 5, France. ULP, CNRS, IPGS EOST, F-67084 Strasbourg, France. CNRS, CNES, LEGOS, F-31401 Toulouse, France. RP Boy, JP (reprint author), NASA, Goddard Space Flight Ctr, Space Geodesy Branch, Code 926, Greenbelt, MD 20771 USA. EM boy@bowie.gsfc.nasa.gov; llubes@notos.cst.cnes.fr; Jacques.Hinderer@eost.u-strasbg.fr; florsch@ccr.jussieu.fr RI Boy, Jean-Paul/E-6677-2017 OI Boy, Jean-Paul/0000-0003-0259-209X NR 39 TC 32 Z9 33 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD APR 10 PY 2003 VL 108 IS B4 AR 2193 DI 10.1029/2002JB002050 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 669ML UT WOS:000182355000003 ER EF